LANDTYPE ASSOCIATIONS

 OF THE

 NORTHERN REGION,

 A FIRST APPROXIMATION

 COMPILED BY

 GARY L. FORD

 C. LEE MAYNARD

 JOHN A. NESSER

 DEBORAH S. PAGE -DUMROESE

 PREPARED IN COOPERATION WITH THE

 SOIL SCIENTISTS OF THE NORTHERN REGION

 USDA FOREST SERVICE

 September 8, 1997

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 1
COMPILERS/EDITORS

Gary L. Ford is a soil scientist with the Idaho Panhandle National Forests in

Coeur d'Alene, Idaho. During this project he was Regional Soil Management

Specialist with the Forest Service Northern Region. He holds a B.S. and M.S.

in Earth Sciences and a Ph.D. in Soil Science from Montana State University.

His primary responsibilities while working for the Regional Office included

soil/Ecological Unit Inventory correlation and Regional coordination of soil

management and monitoring activities.

C. Lee Maynard is a Soil Scientist/GIS Analyst with the Natural Resources

Conservation Service, Helena, Montana. She holds a B.S. in Forest Ecology from

Utah State University and an M.S. in Forest Ecology/Soils from the University

of Montana. During this project she was the East Zone Ecological Mapping

Coordinator for the Northern Region and was responsible for coordinating the

production of the electronic mapping and publication.

John A. Nesser is Regional Soil Scientist with the Forest Service Northern

Region in Missoula, Montana. He holds a B.S. in Geography and an M.S. in

Resource Management (Soils) from the University of Wisconsin -Stevens Point.

His primary responsibilities include management of the Regional soils program

and ECOMAP/Ecological Unit Inventory coordination.

Deborah S. Page-Dumroese is a Research Soil Scientist with the Intermountain

Research Station in Moscow, Idaho. She holds a B.S. in Natural Resource

Management from Grand Valley State University, an M.S. in Forest Soils from

Michigan Technological University, and Ph.D. in Forest Soils from the

University of Idaho. Her main research focus is on maintaining long-term soil

productivity after timber harvesting and site preparation.

ABSTRACT

This document describes the Landtype Associations that have been developed for

National Forest land in the Northern Region. Map units were delineated at a

scale of 1:100,000 and are differentiated by dominant categories of landforms

and geologic materials. Descriptions of the seventy one Landtype Associations

were prepared for the nineteen Sections that occur in Region 1 using the

National Hierarchy of Ecological Units. A total of 40,392,207 acres were

mapped. Examples of applications using landtype associations are also

presented. These landtype associations were developed primarily for use in

landscape and watershed characterization. A geo-referenced, electronic version

of the mapping was prepared as a component of this mapping project.

Key Words: landtype associations, National Hierarchy of Ecological Units,

landforms, geologic materials

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 2
PREFACE

Acknowledgments

Many people contributed their knowledge to this project. Their names are

listed below with their area of expertise.

 Mapping and Map Unit Descriptions

 Skip Barndt, Soil Scientist, Lolo NF

 Bill Basko, Soil Scientist, Flathead NF

 Jeff DiBenedetto, Ecologist, Custer NF

 Pat Green, Soil Scientist/Ecologist, Nez Perce NF

 Annie Greene, Soil Scientist, Beaverhead-Deerlodge NF

 Frank Heisner, Soil Scientist, Custer NF

 Lou Kuennen, Soil Scientist, Kootenai NF

 Larry Laing, Zone Soil Scientist, Helena and Lewis and Clark NFs

 John Lane, Soil Scientist, Custer NF

 Ken McBride, Soil Scientist, Bitterroot NF

 Lee McConnel, Soil Scientist, Custer NF

 Jim Mital, Soil Scientist/Ecologist, Clearwater NF

 Jerry Niehoff, Soil Scientist, Idaho Panhandle NFs

 Barbara Pitman, Geologist, Custer NF

 Dave Ruppert, Soil Scientist, Beaverhead-Deerlodge NF

 Richard Saunders, Soil Scientist, Lewis and Clark NF

 Neal Svendsen, Soil Scientist, NRCS

 Dean Sirucek, Soil Scientist, Flathead NF

 Henry Shovic, Soil Scientist, Gallatin NF

 Bob Spokas, Soil Scientist, NRCS

 Robin Strathy, Geologist, Lewis and Clark NF

 Bo Stuart, Hydrologist, Helena NF

 Dan Svoboda, Soil Scientist/Ecologist, Beaverhead-Deerlodge NF

 Dale Wilson, Soil Scientist, Clearwater NF (retired)

 Geographic Information Systems:

 The Natural Resources Information System

 of the Montana State Library, Helena

 

 Duane Lund

 Peter Langen

 Fred Gifford

 Geomorphic Overview and Geologic Materials

 Jim Shelden, Regional Geologist, R-1

 Jeff Silkwood, Geologist, R-1

 Cartography

 Ted Nyquest, Idaho Panhandle NFs

 Photograph Credits

 Robin Strathy, Larry Laing, Jerry Niehoff, Gary Ford, Ken McBride,

 Pete Bengeyfield, Pat Green, Dean Sirucek, Dan Svoboda, John Lane, 

 and Jack Coyner.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 3
 TABLE OF CONTENTS

 

Chapter 1

 Purpose, Applications, Mapping Methodology, and Limitations of the 

 Landtype Association Mapping

Chapter 2

 Mapping Differentia and Legend

Chapter 3

 LTA Descriptions for Section 331A Palouse Prairie

Chapter 4

 LTA Descriptions for Section M331A Yellowstone Highlands

Chapter 5

 LTA Descriptions for Section M332A Idaho Batholith

Chapter 6

 LTA Descriptions for Section M332B Bitterroot Valley

Chapter 7

 LTA Descriptions for Section M332C Rocky Mountain Front

Chapter 8

 LTA Descriptions for Section M332D Belt Mountains

Chapter 9

 LTA Descriptions for Section M332E Beaverhead Mountains

Chapter 10

 LTA Descriptions for Section M332G Blue Mountains

Chapter 11

 LTA Descriptions for Section M333A Okanogan Highlands

Chapter 12

 LTA Descriptions for Section M333B Flathead Valley

Chapter 13

 LTA Descriptions for Section M333C Northern Rockies

Chapter 14

 LTA Descriptions for Section M333D Bitterroot Mountains

Chapter 15

 LTA Descriptions For Sections With Limited Acreages Of National Forest 

 Land

 251A Red River Valley

 251B North Central Glaciated Plains

 331D Northwestern Glaciated Plains

 331E Northern Glaciated Plains

 331F Northwestern Great Plains

 331G Powder River Basin

 M331B Big Horn Mountains 

 342A Bighorn Basin

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 4
Appendices

 Appendix A: The National Hierarchy of Ecological Units

 Appendix B: Geomorphic Overview of the Northern Region

 Appendix C: Acreage by Landform Groups

 Appendix D: Acreage by Geologic Material Group

 Appendix E: Acreage of Landtype Associations for entire mapping area

 Appendix F: Acreage and proportionate extent of LTAs by Section

 Appendix G: Legend by geologic material and landforms

 Appendix H: List of common and scientific names for vegetation

 Appendix I: Glossary

 Appendix J: References

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 5
List of Figures

 1 Map showing Northern Region and areas for which LTAs were mapped

 2 Map showing abundance of major landform groups

 3 Map showing abundance of major geologic material groups

 4 Map showing zones of metamorphism for Belt Series

 5 Map showing location of 331A within the Northern Region

 6 Landscape photograph Section 331A, Clearwater NF

 7 Map showing distribution of LTAs within 331A

 8 Bar chart showing abundance of landform groups within 331A

 9 Bar chart showing abundance of geologic material groups within 331A

 10 Map showing location of M331A within the Northern Region

 11 Landscape photograph Section M331A, Yellowstone NP

 12 Map showing distribution of LTAs within M331A

 13 Bar chart showing abundance of landform groups within M331A

 14 Bar chart showing abundance of geologic material groups within M331A

 15 Map showing location of M332A within the Northern Region

 16 Landscape photograph M332A, Bitterroot NF

 17 Map showing distribution of LTAs within M332A

 18 Bar chart showing abundance of landform groups within M332A

 19 Bar chart showing abundance of geologic material groups within M332A

 20 Map showing location of M332B within the Northern Region

 21 Landscape photograph Section M332B, Bitterroot NF

 22 Map showing distribution of LTAs within M332B

 23 Bar chart showing abundance of landform groups within M332B

 24 Bar chart showing abundance of geologic material groups within M332B

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 6
 25 Map showing location of M332C within the Northern Region

 26 Landscape photograph Section M332C, Glacier NP

 27 Map showing distribution of LTAs within M332C

 28 Bar chart showing abundance of landform groups within M332C

 29 Bar chart showing abundance of geologic material groups within M332C

 30 Map showing location of M332D within the Northern Region

 31 Landscape photograph Section M332D, Helena NF

 32 Map showing distribution of LTAs within M332D

 33 Bar chart showing abundance of landform groups within M332D

 34 Bar chart showing abundance of geologic material groups within M332D

 35 Map showing location of M332E within the Northern Region

 36 Landscape photograph Section M332E, Deer Lodge-Beaverhead NF

 37 Map showing distribution of LTAs within M332E

 38 Bar chart showing abundance of landform groups within M332E

 39 Bar chart showing abundance of geologic material groups within M332E

 40 Map showing location of M332G within the Northern Region

 41 Landscape photograph Sectin M332G, Nez Perce NF

 42 Map showing distribution of LTAs within M332G

 43 Bar chart showing abundance of landform groups within M332G

 44 Bar chart showing abundance of geologic material groups within M332G

 45 Map showing location of M333A within the Northern Region

 46 Landscape photograph Section M333A, Idaho Panhandle Forests

 47 Map showing distribution of LTAs within M333A

 48 Bar chart showing abundance of landform groups within M333A

 49 Bar chart showing abundance of geologic material groups within M333A

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 7
 50 Map showing location of M333B within the Northern Region

 51 Landscape photograph Section M333B, Flathead NF

 52 Map showing distribution of LTAs within M333B

 53 Bar chart showing abundance of landform groups within M333B

 54 Bar chart showing abundance of geologic material groups within M333B

 55 Map showing location of M333C within the Northern Region

 56 Landscape photograph Section M333C, Flathead NF

 57 Map showing distribution of LTAs within M333C

 58 Bar chart showing abundance of landform groups within M333C

 59 Bar chart showing abundance of geologic material groups within M333C

 60 Map showing location of M333D within the Northern Region

 61 Landscape photograph Section M333D, Idaho Panhandle NFs

 62 Map showing distribution of LTAs within M333D

 63 Bar chart showing abundance of landform groups within M333D

 64 Bar chart showing abundance of geologic material groups within M333D

 65 Landscape photograph Section 251A, Custer NF

 66 Bar chart showing abundance of landform groups within 251A

 67 Bar chart showing abundance of geologic material groups within 251A

 68 Bar chart showing abundance of landform groups within 251B

 69 Map showing location of Great Plains minor units

 70 Bar chart showing abundance of geologic material groups within 251B

 71 Map showing location of Section 331D within the Northern Region 

 72 Bar chart showing abundance of landform groups within 331D

 73 Bar chart showing abundance of geologic material groups within 331D

 74 Map showing location of Section 331F within the Northern Region

 75 Landscape photograph Section 331F, Custer NF

 76 Bar chart showing abundance of landform groups within 331F

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 8
 77 Bar chart showing abundance of geologic material groups within 331F

 78 Map showing location of Section 331G within the Northern Region 

 79 Landscape photograph Section 331G, Custer NF

 80 Bar chart showing abundance of landform groups within 331G

 81 Bar chart showing abundance of geologic material groups within 331G

 82 Map showing location of M331B within the Northern Region

 83 Landtype Association Legend (Part A)

 84 Landtype Association Legend (Part B)

 85 Index Map of 1:100,000 scale quadrange maps

 86 Landscape photograph Section M331B, Custer NF

 87 Bar chart showing abundance of landform groups within M331B

 88 Bar chart showing abundance of geologic material groups within M331B

 89 Map showing location of 342A within the Northern Region

 90 Bar chart showing abundance of landform groups within 342A

 91 Bar chart showing abundance of geologic material within 342A

 92 Map showing geomorphic overview of Northern Region

 93 Map showing Subsection Level of Ecological Units for Region 1

 94 Map showing Colored Relief, Sections and Subsections for Region 1 

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 9
Chapter 1

 

PURPOSE, APPLICATIONS, METHODS AND LIMITATIONS

PURPOSE:

The intent of this project was to develop a set of 1:100,000 scale maps

differentiating the dominant combinations of landforms and geologic materials

(bedrock and surficial) that occur on Forest Service lands throughout northern

Idaho, Montana, and North Dakota (Figure 1). Some areas of other ownership are

included. Map unit delineations were based on a uniform legend and map unit

descriptions were prepared for each of the landtype associations (LTAs)

accounting for variability between Sections. The project also incorporated the

use of a Geographic Information System to develop a continuous, geo-referenced

electronic version of the mapping.

This report reflects our first attempt to translate on-the-ground knowledge

into the landscape scale of the National Hierarchical Framework of Ecological

Units (ECOMAP, 1993). (See Appendix A for a summary of this hierarchy). These

maps and descriptions are a first approximation of the landtype associations

of the Northern Region. Each time the landtype association maps and

descriptions are refined the quality of these products will be enhanced.

Previous ecological unit mapping has been completed at the Section (Bailey and

others 1994a) and Subsection levels ( N esser and others 1997) for the Northern

Region. It is recommended that the reader be familiar with these documents

before using this one. Landtype associations further refine the

characterization of landscapes from Sections and Subsections into units that

describe the composition of landscapes by similarities and repeatable patterns

in landforms, their dominant formative processes, and underlying geologic

materials.

The display of mapped information is not inclusive of all known geomorphic

categories, nor (due to the mapping scale) is it precisely site specific. The

incorporation of a conceptual ecological hierarchy into geo-referenced

delineations requires many interpretive iterations; each at a more refined

scale and level of resolution.

A decision was made to limit this report to the mapping and characterizations

of the LTAs. Interpretations evolve and change, which can make documents such

as this obsolete in a short period of time. For this reason, this report will

only briefly discuss some of the general interpretations and applications

which are appropriate to make using this information. For a more detailed

discussion of site specific interpretations for LTAs and local soil monitoring

results refer to Forest level landscape assessment documents or SOLO (Rice,et

al.1997).

APPLICATIONS OF THE LANDTYPE ASSOCIATION MAPPING:

This mapping is the best single source of information on the soils of the

Northern Region. It can be used by itself to gain an understanding of

landforms and geologic materials throughout the Northern Region, or in

combination with other landscape attributes such as vegetation to support a

wide range of landscape level characterizations. The inherent features of map

units such as the LTAs, which depict the geomorphic environment, generally do

not change with management activities so they can be used as a template for

examining the existing conditions of the land (vegetation, wildlife, etc)

which are subject to change by management or by natural disturbances (Bailey

1994b).

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 10
Landtype associations can be developed for a variety of interpretive purposes.

These Regional LTAs were developed primarily to support landscape level

characterization of watershed properties important to management. The use of

landforms and geologic materials as mapping differentia for this purpose is

based on the assumption that these are features which can be mapped

consistently at the landscape level, and that closely predict significant

differences in watershed, stream, and riparian properties. In addition to

watershed characterization, the LTA’s can be appropriately used to assist with

a variety of landscape level analyses and interpretations. 

The primary utility of this mapping is its use as a stratification tool for

analyzing locations with similar geomorphic attributes and the landscape

properties that these attributes control and influence. When used in

conjunction with the Section and Subsection levels of the ecological mapping

hierarchy, LTA information can also display the distribution and extent of

landform/geologic material groups within regionally specific climatic and

geographic zones.

Fundamental to the appropriate use of the LTA’s is an understanding of the

ecological processes controlled and influenced by geomorphic properties. 

These include: the physical and chemical properties of soils (ie. soil texture

and nutrient status); erosional characteristics; and hydrologic basin

morphometrics. As more is learned about biophysical influences on ecological

processes other relationships will undoubtedly emerge.

Geologic material plays a dominant role in controlling topographic relief, the

development of landforms, and their distribution across landscapes. Landforms,

combined with surficial parent material and other environmental factors such

as climate, greatly influence the textural classes and nutrient status of the

soils that develop. Knowledge of the dominant textural class of soils is

necessary for predicting erosional and depositional characteristics. The

extent and distribution of various kinds of soils influences the extent and

distribution of vegetation. The nutrient status of the soil plays a

significant role in influencing the growth rates and vigor of vegetation.

The distribution and extent of dominant landforms greatly determines the

physiographic features of hydrologic basins. Basin morphology influences the

distribution and extent of unique valley types, riparian and wetland

characteristics, and stream channel properties. The extent and distribution of

unique stream types within any watershed (classified by width/depth ratios, 

particle size distribution, cobble embeddedness, etc.) are closely correlated

with the unique landform/geologic material combinations that are expressed.

Using a Geographic Information System (GIS) and the knowledge of inherent

biophysical landscape relationships, a variety of models have been developed

to provide additional attributes to portions of the LTA map theme. The

inherent and derived attributes have been used to characterize and classify

landscape level ecological units and watersheds throughout the Region. The

following examples are included to illustrate some of these applications for

specific projects throughout the Region:

Mass Wasting/Erosion Potential: To develop this interpretation, each LTA

polygon is further attributed with a minimum, maximum, and mean slope value

from 30 meter resolution Digital Elevation Models (DEMs). In addition, each

LTA map unit is assigned a value for erodability based on research results for

each dominant parent material/soil category. The range of slope attributes

combined with dominant surface and subsurface soil texture values within

unique precipitation zones are then evaluated for potential surface erosion

and mass wasting.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 11
Valley/Stream Type: Delineations of dominant valley types are inherent in the

mapping. Other less prominent valleys and drainages are included as components

or inclusions of many other LTA’s. These can be identified using the LTA map

unit descriptions and can also be displayed visually by using thestreams data

and DEMS for any given location. The composition of valley bottom types within

each LTA is commonly within a fairly narrow range, controlled by the climatic

zone and structural properties of the unit. More refined distinctions of

valley and stream types within each map unit delineation can be derived by

developing distinct slope categories (based on the DEMs) and assigning those

to each stream segment. Stream segments, when assigned an LTA attribute to

assist with the characterization of dominant width/depth ratios, particle size

distribution and other parameters controlled by landform/geologic material can

be more readily classified. Reasonable predictions for stream sinuosity and

Rosgen stream type can also be derived for streams within each LTA map unit

using calculations that combine attributes of the topography and drainage

patterns.

Stream Density/Dissection: A drainage density attribute can be calculated for

each LTA by dividing the sum of the length of all streams per LTA polygon by

the total area per LTA to derive stream miles per square mile of map unit. 

This drainage density ratio can be used to evaluate landscapes for sediment

delivery potential to streams in varying geographic locations.

Sediment Production and Delivery: Using the slope, dominant surface texture

and stream density variable for each LTA polygon, an interpretation can be

made for predicting a generalized range of values for inherent sediment

production and delivery potential for each map unit or combinations of units

within a watershed. To compare existing watershed sedimentation conditions

with natural sedimentation, additional information representing vegetation and

disturbance patterns must be included as steps in the analysis.

MAPPING METHODS:

The geo-referenced electronic data to accompany this mapping project was

created using two primary techniques. In the first, each Forest Soil Scientist

drafted landfom/geologic material delineations on 1:100,000 scale stable base

contour maps. A professional cartographer then transferred these delineations

onto a mylar base registered to the stable contour base map. Each 1:100,000

quadrangle was edge-matched with the adjacent quads during the drafting

procedure. The archival mylar base maps were then electronically scanned at

400 dpi to create a geo-referenced digital file. This drawing was then

transferred into the appropriate coordinate system (Albers Equal Area

Projection) for the 1:100,000 scale quadrangles. A registration error of .007

was accepted as a maximum. Polygon topology was built for each coverage and a

Landtype Association attribute assigned to each polygon. Individual quads were

then electronically edge-matched and joined into draft coverages for larger

geographic areas. This method was employed for those Forests that did not have

complete landtype level mapping available. These included the Idaho Panhandle,

Bitterroot, and Deerlodge Forests.

The second technique used for creating the LTA coverage was applied to those

locations where existing electronic coverage of the 1:24,00 scale Landtype

(Order 3 Soil Survey) mapping was available. In this situation, an LTA

attribute was added to the coverage and each landtype polygon was assigned to

the appropriate landform/geologic material category of the Region 1 legend.

The resulting polygon coverages were then dissolved on the LTA attribute to

display the broader delineations, and were ultimately joined with mapping for

the adjacent Forests.

In both situations, numerous iterations of draft plots of the linework were

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 12
sent to the mappers for review, corrections and additional edge matching. A

final correlation of the mapping was then conducted using final draft maps,

tables of acreages calculating the extent and distribution of all units, and

accessory attribute information. The final resulting coverage was then

associated with the electronic version of the Section and Subsection mapping

to assign the appropriate upper level identifier to each LTA polygon. The

electronic coverage now available represents the last corrected update of this

mapping. The final Regional LTA coverage contains over 33,415 LTA polygons

covering an area of 40,392,207 acres.

Hard copy versions of the mapping for each 1:100,000 scale quadrangle

can be plotted using the map compositions that are included on this CD.

Throughout the Landtype Association mapping project, Geographic Information

System (GIS) hardware, software, and technical expertise were provided through

a cooperative agreement with the Natural Resource Information System (NRIS) of

the Montana State Library. Digital data were processed using a SPARC 20 UNIX

workstation running Version 7.04 of the ARC-INFO program. The LTA coverage

can be retrieved from the Management Systems Group of Region 1.

LIMITATIONS OF THE MAPPING

As with any map product, the basic principles of scale apply to the LTA

mapping. The Landtype Associations provided in this publication were compiled

at a scale of 1:100,000 and should be used for stratification purposes only at

larger scales such as 1:24,000.

The Sections were mapped at 1:1,000,000; the Subsections at 1:500,000. For

this reason when displayed in relationship to the LTA’s their boundaries are

only approximately located. Section and Subsection delineations were

electronically incorporated into the LTA coverage for referencing and

attributing purposes only. The upper level delineations were not adjusted to

the 1:100,000 map scale in the GIS processing resulting in ‘slivers’ that are

artifacts of combining information generated at different scales. 

Consequently, data summaries may show some LTAs as occurring in one Section or

Subsection which may actually occur in the adjacent unit. Future refinements

of all levels of the ecological mapping will provide the opportunity to adjust

these delineations. Time constraints prohibited that from occurring in this

first approximation.

 

At the present time, geologic mapping is incomplete in some areas. While this

LTA mapping used the best available geologic information, it will be possible

to improve the landtype associations as new geologic maps become available.

This project was initiated to map Landtype Associations on National Forest

land and is not intended to be the primary source of information for other

ownerships. Readers desiring information on private land should consult their

local Natural Resource Conservation Service office. Where Bureau of Land

Management, National Park Service, or Tribal lands are of interest, contact

their nearest office for information.

The authors of this document and compilers of the map series realize that

there may be errors due to time or information constraints that we have failed

to recognize and correct. Users of this information are encouraged to submit

corrections to the Regional Soil Scientist for incorporation into the second

approximation.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 13
Chapter 2

MAPPING DIFFERENTIA AND LEGEND

Map Unit Differentia:

At the Landtype Association level, ecological units delineations incorporate

the intended use of the map; features used to delineate polygons are referred

to as the differentiating criteria. The differentiating criteria for the LTA

mapping were the dominant types of landforms and geologic materials that occur

on National Forest lands in the Northern Region. The landform and geologic

material groups that were used in the mapping are described in the following

sections.

Other attributes (accessory characteristics) are also described for each map

unit, but were not used as delineation criteria. Accessory characteristics

described for the LTA's include: elevation range, slope range, average annual

precipitation, surface and subsoil textures and rock fragment contents, stream

pattern and density, soil taxa at the subgroup level, and potential vegetation

at the series level.

The legend that was developed for the LTA mapping project was designed to

cover the major types of landforms and geologic materials that occur

throughout the Northern Region. Where differences in landform or geologic

materials occurred, they were separated into the landform groups, rock types,

or weathering classes listed in the legend. 

In some areas, such as the continentally glaciated Belt rocks, the geology is

relatively simple and it was possible to prepare a single map unit description

for each LTA that occurred in a Section. Where the geology is more complex, it

was not possible to do this. In these cases, Subsections were used as the

basic template for separating differences in LTAs. If a Section had

occurrences of the same general landform and geologic type but with very

different accessory characteristics (soils, climate, potential vegetation). 

the preferred way of addressing these differences was to separate the Map Unit

Descriptions (MUD’s) by Subsection.

General Discussion of the Landform Groups

The following fifteen major landform groups were used in the mapping of LTAs.

See Figure 2 for a display of their general occurrence throughout the Region.

Appendix C contains the acreage figures for landform groups.

 Valleys

 Breaks

 High Relief Mountain Slopes

 Steep Glaciated Mountain Slopes

 Glaciated Mountain Slopes

 Mountain Slopes and Ridges

 Frost Shattered Mountain Ridge Tops

 Low Relief Hills

 Mass Wasted and Colluvial Slopes

 Glaciated Plains

 Sedimentary Plains

 Badlands

 Glaciolacustrine Plains

 Erosional Plateaus and Buttes

 Hills and Plateaus

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 14
 Eroded Uplands

These landform groups are described below using the following criteria:

 1) Primary landforms

 2) Process of development

 3) Slope gradient

 4) Surface shape

 5) Associated landforms

VALLEYS: The primary landforms included in this unit are floodplains,

terraces, and alluvial basins formed by recent streams or by glacial

meltwater. A variety of water-deposited sediments occur in these valleys. The

alluvial deposits vary from poorly sorted and stratified to well sorted and

stratified; some dune deposits also occur. These units typically have straight

or convex slopes that range in gradient from 0 to 30 percent. They may also

contains narrow terrace escarpments which can be much steeper. The surface

shape typically is level to very gently rolling. Associated landforms include

both glaciated and unglaciated mountains slopes and gently to moderately

sloping hills. Due to the scale of the mapping only major valleys are

delineated. Smaller valleys and drainages are described as components of other

map units.

BREAKS: In the Northern Region these are frequently referred to as

breaklands. The more commonly accepted term of Breaks is used in this

publication. The two main types mapped were structural breaks and stream

breaks. The primary landforms included in this unit are breaks and

escarpments. These generally have straight slopes in excess of 60 percent,

with a slope range from 50 to greater than 100 percent. Breaks typically have

abrupt changes to gentler slopes with the adjacent landforms. These landforms

have developed by tectonic activity and/or rapid stream downcutting processes.

In some places they have been modified by glacial action. Associated landforms

include mountain slopes and ridges, and alluvial valley floors. These units

occur primarily in western Montana and north Idaho.

HIGH RELIEF MOUNTAIN SLOPES: Unglaciated mountain slopes of high relief. In

general, an elevational change of greater than 244 meters (800 feet) is common

to these units. Slope gradients are greater than 40 percent. These units were

primarily mapped east of the Continental Divide.

STEEP GLACIATED MOUNTAIN SLOPES: The primary landforms included in this unit

include cirque headwalls, glacial troughwalls, alpine ridges and cirque

basins. These landforms are predominantly formed by alpine glacial erosion

processes but include areas of glacial deposition. Due to the scale of the

mapping and the close physical association of these landforms, they were

combined into a single map unit. Cirque headwalls and glacial troughs

typically have straight or concave slopes that range in gradient from 50 to

greater than 100 percent. Alpine ridges have convex slopes ranging from 10 to

40 percent. Cirque basins are typically bowl-shaped landforms with gradients

from 0 to 30 percent.

Associated landforms include gentle to moderately sloping glaciated lands,

mountain ridge tops, and valley floors. This steep glaciated map unit has

characteristics similar to the gentle to moderately sloping glaciated land

produced by continental glaciation; however that unit typically has more

subdued topography and occurs at lower elevations. This unit also includes

broad, ice-cap ridges having less than 40 percent slopes and equal amounts of

subdued glacial erosion and deposition. These units were mapped throughout the

mountainous areas of the Region.

GLACIATED MOUNTAIN SLOPES: The dominant landforms include glacial moraines,

glaciated mountain slopes, and glaciated mountain ridetops. These landforms

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 15
represent depositional and erosional surfaces formed primarily by continental

glaciation with some areas modifed by alpine glaciers. These surfaces have

subdued relief with rolling topography. They are a combination of eroded,

convex ridges, glacial deposits on slightly concave valley sideslopes, and

deep glacial deposits on valley floors. Slope gradients range from 15 to 50

percent. Associated landforms include gentle to moderately sloping frost

shattered ridges and sideslopes, steep glaciated lands, and glacial outwash

and glaciolacustrine landforms. These were mapped primarily in northwest

Montana and north Idaho.

MOUNTAIN SLOPES AND RIDGES: The primary landforms are ridges and sideslopes

that have formed by fluvial and colluvial processes. The ridges are generally

convex and the sideslopes are straight. Slope gradients generally range from

20 to 65 percent with 35 to 60 percent being dominant. A variety of

weathering classes are expressed. Infrequent small nivational basins are

included. Associated landforms are valley floors, and steep glaciated lands

where alpine glaciers have been active at higher elevations. Some broader

ridges may also occur where frost action has occurred. These were mapped

throughout the Region south of the continentally glaciated areas.

FROST SHATTERED MOUNTAIN RIDGETOPS: The mountain ridge top is a broad convex

landform that commonly occurs above mountain slopes and adjacent to steep

glaciated lands. They have formed mainly by physical weathering and

periglacial frost shattering. They are usually undissected. Slope gradients

range from 5 to 40 percent. As mapped, these landforms can include small

areas of weak glacial erosion and deposition. The geologic materials commonly

have a high rock fragment content which has been loosened and mixed by frost

action and other weathering processes. Rock outcrops are infrequent. Frost

shattered mountain ridge tops were mapped primarily at higher elevations in

western Montana and north Idaho.

LOW RELIEF HILLS: This group consists primarily of low relief hills (less than

100 meters) with lesser amounts of alluvial fans, terrace remnants and

colluvial slopes. These landforms are the result of shallow stream dissection

of deeply weathered surfaces. They are frequently protected from deep

dissection by nick points. Slope gradients are generally less than 45 percent

with a typical range of 20 to 40 percent. Surface shape consists of simple to

complex slopes of all shapes. Associated landforms are recent terraces and

fans, hills and mountain slopes, deep frost shattered ridges, and slopes.

MASS WASTED AND COLLUVIAL DEPOSITS: The dominant landforms are rotational and

translational failures. Included are a variety of types of failures, such as

debris avalanches, slumps, and deep mantle failures. Slope gradients for the

translational failures are generally greater than 50 percent and commonly

occur on the steep mountain sideslope units, either glaciated or unglaciated.

Rotational failures generally occur on lower slope gradients on the gently to

moderately sloping mountain sideslope units, either glaciated or unglaciated.

Associated landforms, in addition to the mountain sideslope units, are ridge

tops at higher elevations and valley floors at lower elevations. Generally

small in size (less than 50 acres), these units may also occur as inclusions

in other landform groups.

GLACIATED PLAINS: The primary landforms in this unit include glaciated

rolling plains and glaciated dissected plains. These landforms resulted from

the deposition of glacial till from continental glaciation, and also by

lacustrine and deltaic sediments from glacial lakes. Glaciated rolling plains

consist of hills and swales or slightly dissected, slightly entrenched

drainageways. Slopes are usually less than 15 percent and relief is less than

200 feet. Glaciated dissected plains consist of hills and moderately to

strongly dissected and entrenched drainageways. Slopes are usually

15 to greater than 40 percent and relief is usually greater than 60 meters

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 16
(200 feet). Associated landforms include sedimentary rolling and dissected

plains, breaks, and valleys. Glaciated plains were mapped on the Custer

National Forest.

SEDIMENTARY PLAINS: The primary landforms in this unit include rolling plains

and dissected plains. These units have formed in sandstone and shale sediments

as a result of chemical and physical weathering, fluvial and colluvial

processes. Rolling plains consist of hills and swales or slightly dissected,

slightly entrenched drainageways. Slopes are usually less than 15 percent and

relief is less than 60 meters (200 feet). Dissected plains consist of hills

and moderately to strongly dissected and entrenched drainageways. Slopes are

usually 15 to greater than 40 percent and relief is usually greater than 200

feet. The surfaces are level to steep with slopes usually less than 45

percent. Associated landforms include glaciated rolling plains, glaciated

dissected plains, badlands, breaks and valleys. Sedimentary plains were mapped

on the Custer National Forest.

BADLANDS: The primary landforms in this unit include hills, knobs, alluvial

fans, ridges and drainageways. These landforms have developed from erosion

caused by infrequent heavy showers on sparsely vegetated landscapes. This has

resulted in rough, narrowly and steeply gullied topography where soft bedrock

of shale and sandstone are widely exposed. Runoff is very rapid and

permeability is very slow. Little true soil development has taken place and

erosion is active. Vegetation is limited to bottoms of draws, smooth benchl ike 

areas, or gentle slopes where soil can form or has not been eroded. The

surfaces are sloping to steep. Slope gradients range from 5 to greater than

45 percent. Associated landforms include rolling plains, dissected plains, and

valleys. Badlands were mapped on the Custer National Forest.

GLACIOLACUSTRINE PLAINS (Deltaic Plains/Eolian Deposits): The primary

landforms include glacial lake deltaic deposits, sandhills and dunes. These

landforms developed from the deposition of sediments at the mouth of the

Sheyenne River as it discharged into glacial Lake Agassiz which filled the Red

River Valley of North Dakota and Minnesota. The deltaic deposits consist of

very fine to fine grained sand, a transition zone of interbedded silt and sand

and silt and clay. The sands were then redistributed and moved by the wind

into the dunelike topography presently in the area. Glacial lake deltaic

deposits consist of nearly level hills and swales. Slopes are usually less

than 5 percent and relief is less than 3 meters (10 feet). Sandhills and

dunes consist of hills, dunes and hummocks that are slightly dissected, and

slightly entrenched. Slopes are usually 5 to 20 percent and relief is usually

less than 25 feet. Associated landforms include valleys. Glaciolacustrine

deltaic plains and eolian deposits were mapped on the Custer National Forest.

EROSIONAL PLATEAUS AND BUTTES: The primary landforms in this unit include

nearly level to flat topped summits and relatively steep slopes or cliffs.

These landforms were formed as a result of erosion by water. The landforms are

a remnant of a higher surface and are typically capped with erosion resistant

rocks. The summits are nearly level to flat with slopes from 0 to 12 percent.

The steep slopes often contain rubble and talus and slope gradients are 25 to

greater than 90 percent. Associated landforms are rolling and dissected

plains, badlands, and valleys.

HILLS AND PLATEAUS: The plateaus are associated with flows of Columbia River

basalt. The hills are usually associated with deposits of wind blown loess.

Hills and plateaus were mapped on the Clearwater National Forest.

ERODED UPLANDS: These areas are transitional between higher elevation

plateaus and lower elevation plains. They are not as gullied, can have more

relief, and have more vegetation than the badlands. The primary landforms in

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 17
this unit include ridges, plateau remnants, hills, and drainages. These

landforms were formed by stream erosion. Plateau remnants are nearly level to

flat. Ridges and hills have straight to concave steep slopes. Slopes generally

range from 15 to 60 percent. Associated landforms are plateaus, dissected

plains, and valleys. Eroded uplands were mapped on the Custer National Forest.

General Discussion of Geologic Material Groups:

Twelve geologic material groups were used for the Landtype Association mapping

and are listed below:

 Schists and Gneisses (usually weakly or moderately weathered)

 Metasedimentary (Belt) (vary with degree of metamorphism)

 Quartzites (frequently mapped with schists and gneisses)

 Sandstones and Shales

 Carbonates

 Granitics (weakly, moderately and highly weathered classes)

 Volcanics

 Calc-silicates

 Loose Sediments

 Fine Sediments: lacustrine, ash and loess

 Coarse Sediments: till, wind deposited sand, talus

These groups are briefly summarized below. See Figure 3 for a small scale map

showing their distribution throughout the Region. Appendix D contains the

acreage figures for the geologic material groups.

SCHIST AND GNEISS: This includes all schists and gneisses in the Region

regardless of age or origin. Included are the Archean basement rocks (about

2.8 billion years old) exposed in the Beartooths, the metamorphosed Belt rocks

of Zone 3 (described in the Belt section which follows) and the rocks which

occur in the Western Idaho Suture Zone (WISZ). This is a zone of intensely

metamorphosed rocks that started as Belt or granitics and are now gneisses and

schists. During this process the rocks were mechanically abused as well,

resulting in a weak broken material subject to deep chemical weathering, shot

through with planes of failure and resulting in erosive weathering products

such as grus or fine micaceous sand. The old term for this area was `Border

Zone’, when it was thought to be the result of intrusion of the Idaho

Batholith. The change to WISZ reflects a newer understanding that in addition

to the effects of the batholith, this is the collision zone where Washington

and Oregon docked when they were added to the Idaho coast. Throughout this

area schists, gneisses and quartzites are mapped together.

METASEDIMENTARY (Belt): The Belt Supergroup is the bedrock of about 65

percent of the Northern Region. Because of its complex history these rocks

assume a wide variety of lithologies and appearances. Many of these are

described here under other categories, such as calc-silicates, WISZ, schists

and gneisses depending on their metamorphic grade. For this document, Belt is

defined as that portion of the Belt lithology that is dominated by alternating

thin beds of argillite, siltite, and quartzite. It includes thick carbonate

units at the bottom and in the middle. It also includes large dark colored

intrusives shot in along bedding planes. This occurs most commonly in the

lower, older rocks. The Region is divided into three zones based on

metamorphic grade (see Figure 4).

In the extreme east is Zone One, extending from the Little Belts east and

northward. This is the least metamorphosed area of the Belt basin with the

rocks being only slightly altered and much more like sedimentary rocks.

Zone Two makes up the bulk of the Region extending to the Idaho line near

Missoula to Coeur d'Alene and northward. In this zone the rocks are harder.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 18
Slaty cleavage shows but they are still recognizable as sediments.

Zone Three extends to near Orofino, Idaho where it merges into the Western

Idaho Suture Zone (WISZ) explained below. These rocks are where sediments

begin to turn into schist and gneiss and become increasingly hard to recognize

as sediments. Belt time spans the period of 2.2 billion to about 850 million

years ago.

QUARTZITES: Refers to the Flathead Formation where it is a quartzite, and the

Quadrant Formation. The Flathead lies atop the Belt rocks on a regional scale

unconformity. It is early Cambrian in age spanning the time 570 to 550 million

years. The Quadrant is Pennsylvanian (about 4000 feet above the Flathead)

spanning 320 to 290 million years. Both formations have blocky outcrops, low

fertility, and excessively drained sites. They both tend to be resistant

ridge formers and nickpoints in the landscape.

SANDSTONES AND SHALES: Refers to all sedimentary strata above the Cambrian

not dominated by carbonates, or large quartzite units. This does not include

the unindurated Tertiary Sediments. These are the less resistant clastics that

underlie rounded hills or are swales in the landscape. Some of the larger

sandstones are ridge formers and moderately resistant. These span from 600

million to 1.7 million years. Sandstones and shales occur mostly in central

and eastern Montana and in North Dakota.

CARBONATES: Refers to all carbonates, including dolomites, above the

Cambrian. The most prominent formations are paleozoic in age including

Cambrian Meagher and Pilgrim Formations, and the Devonian aged Three Forks

Formation. The largest is the Mississippian Madison Group. These units tend

to be resistant ridgeformers. This position in the landscape allows the

chemically reactive erosion products to move downslope with gravity, mixing

with and adding lime to all the soils below them. Structurally controlled

drainages and stable drainageways are features of landscapes in these units.

Water chemistry is dominated by carbonate influence. Karst and dramatic water

loss from perennial streams is common as are large volume springs. Many

thermal springs originate from these formations.

GRANITICS: Refers to all light colored intrusive rocks of any age. Most of

these masses date from late Cretaceous to early Tertiary (70 to 55 million). 

Important properties stem from the fact that they occur as large homogenous

masses of equagranular rock made up of minerals with different properties. In

moist regimes exposed to soil acids they are very reactive to chemical

weathering, while in dry or nonacid regimes are very resistant. This leads to

landforms at the ends of the spectrum being made of the same material. Where

covered with soil and vegetation, it makes weak, gentle, rounded landforms and

is erosive, while where bare it is resistant, fresh, and rugged. This also

affects the nature of sediments produced. The weathering product- grus is

equagranular, noncohesive, and very erodible and is primarily in the medium to

coarse sand range. Fresh material makes cobbles and boulders that persist and

are resistant in running water. The granitics occur in north Idaho and western

Montana as a number of igneous bodies such as the Idaho, Boulder an Kaniksu d

Batholiths along with related intrusives.

To maintain uniformity between forests in mapping granitic weathering classes,

the system developed by Clayton and Arnold (1972) was used and should be

consulted for more information. In the LTA map unit descriptions if granite is

listed without a weathering class it is described as unweathered or weakly

weathered. Moderate and highly weathered modifiers are used where these

classes occur. A brief summary of weathering classes defined in this

publication is given below. These definitions were used to classify

the degree of weathering of the granitic materials.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 19
 Unweathered: This corresponds to class 1 being fresh unweathered

material. It is most common in glacially scoured landscapes where it has been

protected from vegetation by slope, altitude, or running water. Cracks are

fresh and sharp, it rings when hit with a hammer, and crystals are sharp and

fresh including the black mica.

 Weakly weathered: This corresponds to Classes 2 and 3. It represents the

first stages of weathering including features like weak iron stains emanating

from the black mica, and the feldspars turning from fresh white or transparent

to a cloudy white condition. It gives a duller sound when struck with a

hammer.

 Moderately weathered: This corresponds to classes 4 and 5 including

material that spalls (crumbles) and gives a dull thud when hammered. This

material requires a hammer to break and does not generally go directly to

grus.

 Highly weathered: This corresponds to classes 6 and 7. This covers

materials that extend from that which goes directly to grus and can be broken

by hand, up to material where feldspars have gone to clay and material that is

plastic when wet.

VOLCANICS: Refers to all extrusive rocks regardless of age or composition.

The region is bimodal having a lot of lava with minimal silica in it (basalt),

containing little ash, scoria or welded material in far ranging flows, or

having a lot of ashy welded rocks with abundant silica with short trashy flows

intermixed. This leads to the two class definitions:

 Basalt dominated: These are the great flood basalts of the Columbia River

Plateau. They typically have the flat upper surface of a fluid lava flow. They

are deeply dissected by the main trunk streams forming the characteristic

stepped breaks controlled by resistant flows. These units also include

paleosols and gravel interbeds that are locally important in controlling

stability and groundwater. The resistant beds are nickpoints in many

drainages. These rocks are alkaline and the groundwater and surface water

reflect this. They are Miocene (17 million to 8 million years) in age. The

basalts are most abundant in Idaho.

 Intermediate composition (andesite-rhyolite) dominated: These rocks are

piles of siliceous volcanic rocks that fell out of the air or slid down the

sides and were welded into rock by their remaining heat, mixed with lava

flows, mudflows, mass failures, and ash falls. They tend toward rounded gentle

landforms until flow or solidly welded material approaches 50 percent of the

pile; these act as resistant units. The ash typically weathers rapidly to

clays. These layers greatly affect stability and act as aquatards for perched

aquifers and determine seep horizons. Slumps and landslides are common, even

pervasive in many landscapes dominated by these rocks. The andesites and

rhyolites are most abundant in Montana.

CALC-SILICATES: These are the mid-Belt carbonates where they have been

subjected to metamorphism such that little carbonate remains (Middle Wallace

Formation of the Belt Supergroup). Where referred to as dirty carbonates, the

carbonate has reacted with soil to become calcium aluminum, or calcium

magnesium silicates. There are often zones of schist or gneissic rocks

included. The calc-silicates were mapped mostly on the Bitterroot National

Forest.

LOOSE SEDIMENTS: This refers to all unindurated material. This is Quaternary

to Recent material spanning the last 1.7 million years. This material tends to

be bimodal, either predominantly coarse or fine.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 20
 Fine grained: (<.25 mm or <60 mesh) This is predominantly sediment

deposited in ponded water (lacustrine sediments) or wind deposited ash and

loess. The largest expanses are from lakes ponded by ice during the ice ages,

or mass failure dams in smaller drainages. This includes fine colluvial

material or mass failures in any of this fine grained material. The loess

occurs mostly in Idaho, while the volcanic ash occurs in both north Idaho and

western Montana. Glacial lake deposits occur in north Idaho and western

Montana.

 Coarse grained: (>.25 mm or >60 mesh) This includes coarse material

deposited by modern streams, glacial meltwater, glacial till and wind

deposited sand. Also included are gravity deposits, such as talus or mass

failure in coarse materials. An unusual occurrence is that of coarse delta

deposits into Lake Missoula in western Montana. The continental till occurs in

north Idaho and northwest Montana. Alpine till occurs many high elevation

mountainous areas throughout the Region. Areas which were occupied by ice caps

or piedmont glaciers occur in western Montana. The sandhills and sand dunes

are most abundant on the Custer National Forest.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 21
THE MAP LEGEND

Listed below is the legend used for the mapping. It is organized with the

first subdivision being landform and the second being geologic material. The

number given is the LTA identifier. For the convenience of the user, Appendix

H contains a second version of the legend which is arranged by geologic

material first and landform second. Figures 83 and 84 display the legend

categories with the colors used on all maps showing the LTAs.

Plains

 1 Shales, Siltstones and Sandstones

Glaciated Plains

 2 Shales, Siltstones and Sandstones

Dissected Plains

 3 Shales, Siltstones and Sandstones

Glaciated Dissected Plains

 4 Shales, Siltstones and Sandstones

Badlands

 5 Shales, Siltstones and Sandstones

Eroded Uplands

 6 Volcanic Tuffs, Shales, Siltstones, and Sandstones

Erosional Plateaus and Buttes

 7 Shales, Siltstones and Sandstones

Glaciolacustrine Plains

 8 Glacial Lake Deltaic Sediments

 9 Sandhills and Sand Dunes

Valleys

 10 Recent Coarse Alluvium

 11 Lacustrine Sediments

 12 Outwash and Other Older Coarse Alluvial Deposits

 13 Fine Glacial Sediments

 14 Recent Fine Alluvium

Hills and Plateaus

 17 Loess

Breaks

 20 Metasedimentary (Belts)

 21 Granitics, Highly Weathered

 22 Granitics, Weakly Weathered

 23 Schists and Gneisses

 24 Volcanics

 25 Sandstones and Shales

 26 Gneisses, Quartzites, SchistS, Moderately Weathered

 27 Carbonates

 28 Metasedimentary (Dissected Belt Breaks)

 29 Quartzites and Calc-silicates

High Relief Mountain Slopes

 34 Volcanics

 36 Sandstones and Shales

 37 Carbonates

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 22
Steep Glaciated Mountain Slopes

 39 Gneisses, Schists and Associated Metamorphics

 40 Metasedimentary (Belt)

 41 Granitics and Other Coarse Grained Intrusive Rocks

 42 Volcanics

 43 Carbonates

 44 Sandstones and Shales

 46 Alpine Troughs and Troughwalls, Granitics

 47 Alpine Troughs and Troughwalls, Belts

Glaciated Mountain Slopes

 35 Weakly Glaciated Mountain Slopes and Ridges,

Calci-silicates

 and Quartzites

 45 Weakly Glaciated Mountain Slopes and Ridges, Granitics

 50 Metasedimentary (Belts)

 51 Granitics

 53 Sandstones and Shales

 54 Volcanics

 57 Gneisses, Schists and Associated Metamorphic Rocks

 58 Highly Weathered Belt Till

Mountain Slopes and Ridges

 59 Gneisses, Quartzites, Schists, Moderately Weathered

 60 Metasedimentary (Belt)

 61 Granitics, Highly Weathered

 62 Granitics, Weakly Weathered

 63 Schists, Gneisses and Associated Metamorphics

 64 Volcanics

 65 Soft Sedimentary Rocks

 66 Carbonates

 67 Quartzites and Calci-silicates

 68 Sandstones and Shales

 69 Pediment, Mixed Geology

Frost Shattered Mountain Ridge Tops

 70 Metasedimentary (Belt)

 71 Granitics, Highly Weathered

 72 Granitics, Weakly Weathered

 73 Volcanics

 74 Sandstones and Shales

 75 Calc-silicates and Quartzites

 77 Gneisses, Quartzites, Schists, Moderately Weathered

Low Relief Hills

 80 Metasedimentary (Belt)

 81 Granitics, Highly Weathered

 82 Volcanics

 83 Fine Tertiary Sediments

 84 Schists, Highly Weathered

 85 Gneisses, Quartzites, Schists, Moderately Weathered

 88 Coarse Tertiary Sediments

Mass Wasted Slopes

 90 Mixed Geology

Colluvial Slopes

 92 Mixed Geology

Water

 99 Lakes and Reservoirs

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 23
OVERVIEW OF THE LANDTYPE ASSOCIATION DESCRIPTIONS:

The seventeen landform groups and twelve geologic materials groups were

combined to produce seventy one Landtype Associations for the Northern Region.

Some of these LTAs occur across very large areas and therefore have many

differences in accessory characteristics (soils, climate, potential

vegetation) which are addressed by identifying and describing each LTA based

on the Section in which it occurs.

When an LTA occurred in more than one Section, a separate MUD was prepared for

each Section. The exception to this was if an LTA occurred in adjacent

Sections and the two occurrences were considered to have similar enough

characteristics that one MUD could be prepared to address both Sections. In

this case a single MUD was prepared for multiple sections-each identified at

the beginning of the MUD. One of the reasons it was possible to write a single

MUD to cover the occurrence of an LTA in several Sections is that the higher

levels of soil taxonomy (subgroup) and PNV classification (series) were used

for the landtype association characterization.

Some Sections have a few landtype associations which occupy large acreages and

are clearly the major units; other LTAs in each Section are of lesser acreage

and can be considered minor units. LTAs which have very limited acreage may be

considered incidental. An LTA can be a major unit in some Sections, a minor

unit in others, and incidental or not present in other Sections. The

geomorphic complexity of some Sections in the Northern Region is evident when

evaluating the composition by LTA. For example, the Yellowstone Highlands

(Section M331A) has occurrences of thirty different LTAs. As an interpretation

aid, bar charts summarizing the LTA information into landform and geologic

material groups by Section are included in each chapter.

In cases where the same LTA occurred in different Subsections of the same

Section and had very different accessory characteristics in each location,

MUDs were prepared for these LTAs distinguished and characterized by

Subsection. In the map unit descriptions which follow, the MUDs that were

prepared for single subsections are listed first, and are followed by the MUDs

for the rest of that LTA in the Section.

The map unit descriptions for the landtype associations are presented in the

following chapters. Preceding the map unit descriptions for each Section is a

map showing the location of that Section within the Region, a landscape

photograph from that Section, a map showing the distribution of LTAs within

that Section and bar charts showing the distribution of major landform groups

and geologic material groups. The map unit descriptions have the following

format.

LTA symbol: The LTA identifier is hyphenated to include the Section label.

Landform name; type of geologic material. If the LTA description is for a

single Section, the identifier at the top of the description would follow the

format of LTA number then Section Symbol, such as LTA 20-M331A. If one MUD

covers two Sections, the identifiers are written as LTA10-M332A, LTA10-M332B.

Location: River drainage, Mountain Ranges, National Forest

Acreage by Section: number of acres of this LTA which occur in each Section

(or subsections in some cases) covered by this map unit description.

LTA Setting and General Characteristics

Differentiating Characteristics: Geologic materials and landforms used to

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 24
differentiate this unit from the others.

Accessory Characteristics: General soil characteristics, general type of

vegetation, mean annual precipitation range, elevation range, dominant slope

gradient, stream pattern and density

LTA Components: Identification of major landscape components described in the

following paragraphs.

Description of landforms, geologic materials, soil characteristics, slope

gradients, soil classification at subgroup level, potential natural vegetation

at series level, and percent of the LTA that is occupied by this landscape

component.

Compiled by: The name of person who prepared this map unit description and

their home unit.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 25
CHAPTER 3

LTA Descriptions

Section 331A Palouse Prairie

This Section occurs in west central Idaho and includes portions of the Columbia

River Basalt and Idaho Canyonland geomorphic areas previously described. 

LTA Summary: 19 LTAs were mapped in this Section. Nearly half (45%) of the

Palouse Prairie that occurs within the Northern Region is dominated by loess

covered hills and plateaus (LTA17). Volcanic breaklands (LTA29),

metasedimentary mountain slopes and ridges (LTA60), and low hills underlain by

Tertiary sediment deposits (LTA83) occupy most of the remaining landscape.

River valleys account for less than 2% of the mapped area ( LTA's 10 and 12).

Map unit descriptions are preceded by the following illustrations:

 Figure 5: Map showing location of 331A within the Northern Region

 Figure 6: Section 331A Palouse Prairie landscape photograph.

 Clearwater National Forest 

 Figure 7: Map showing distribution of LTAS within 331A

 Figure 8: Bar chart showing abundance of landform groups within 331A

 Figure 9: Bar chart showing abundance of geologic material groups

 within 331A

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 26
LTA10-331A

VALLEYS: RECENT COARSE ALLUVIUM

Location: This unit is located in the Potlatch and Clearwater River Basins of

north-central Idaho.

 Acreage by Section

 10-331A 11,035

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a valley bottom

landscape setting, which is typically composed of floodplains, alluvial

basins, and stream terraces. Parent materials are recent, coarse alluvial

deposits primarily underlain by Columbia flood basalts.

Accessory Characteristics: The primary soils are deep to very deep loams or

silt loams over gravelly or cobbly sand or loamy sand substrata. The

vegetation is a mosaic of deciduous and coniferous forest, riparian shrub

communities, and mesic to wet meadows. Mean annual precipitation ranges from 33

to 76 cms. (13 to 30 inches). The elevation range is 244 to 366 meters (800 to

1200 feet). The dominant slopes have gradients of 0 to 10 percent. This unit

is moderately dissected by streams, with the dominate stream pattern being

dendritic. Wetlands and ponds are a major component of this unit.

LTA Components: This landtype association consists of floodplains, alluvial

basins, and stream terraces.

Floodplains and alluvial basins are formed in moderately coarse textured recent

alluvium. Slope gradients range from 0 to 3 percent. Soils on these landforms

are deep, weakly to moderately developed, and consist mostly of cobbles,

gravel, and sands. These soils are classified as Aquic Haploxerolls and Aquic

Xerofluvents. Rock outcrop occurs on less than 1 percent of this landscape

component. The dominant potential natural vegetation is mesic to wet

grass/sedge associations, willow/alder associations, and Ponderosa

pine/Douglas-fir series. This component represents 75 percent of this unit.

Stream terraces are formed in mixed, coarse textured alluvium. Slope gradients

range from 2 to 10 percent. Soils on these landforms are deep, weakly

developed, and consist mostly of medium to moderately fine textures over sand,

gravel, and cobble sized rocks. These soils are classified as Fluvaquentic

Haploxerolls and Fluventic Eutrochrepts. Rock outcrop occurs on less than 1

percent of this landscape component. The dominant potential natural vegetation

series are ponderosa pine, Douglas-fir, and willow/cottonwood associations.

This component represents 20 percent of this unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 27
LTA12-331A

VALLEYS: OUTWASH AND OLDER COARSE ALLUVIUM

Location: This unit is located in the Clearwater River Basin in north central

Idaho.

 Acreage by Section

 12-331A 4,483

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs on valley bottoms of

canyon breaklands and is dominated by old high terraces. These occur with low

flood plains and alluvial fans. Parent materials are mixed alluvium underlain

by undifferentiated lithology.

Accessory Characteristics: The primary soils are very deep sands, sandy loams,

and loams over cobbles and gravels. The vegetation is a mosaic of grassland

and coniferous forest with some unvegetated cobble and sand bars. Mean annual

precipitation ranges from 51 to 64 centimeters (20 to 25 inches). The

elevation range is 366 to 458 meters (1200 to 1500 feet). The dominant slopes

have gradients of 1 to 20 percent. This unit is adjacent to large rivers and

may be dissected by smaller streams. In low floodplains and fans, wetlands and

cobble and sand bars are numerous. 

LTA Components: This landtype association consists of older terraces and

floodplains.

Old terraces are formed in old alluvium and loess. Slope gradients range from 1

percent on terrace floors to near vertical on truncated terrace faces. Soils on

these landforms are very deep, moderately developed sandy loams and loams with

loamy substrata. These soils are classified as Typic Haploxerolls. Rock

outcrop is uncommon. The dominant potential natural vegetation series are

bluebunch wheatgrass and ponderosa pine. This component represents 65 percent

of this unit.

Floodplains are formed in ecent alluvium of mixed lithology. Slope gradients

range from 1 to 3 percent. Soils on these landforms are deep to very deep,

poorly developed stratified sands, gravels, cobbles and some fine material.

These soils are classified as cobbly Typic Xerofluvents. Rock outcrop is

uncommon. The dominant potential natural vegetation series are bluebunch

wheatgrass and ponderosa pine. This component represents 30 percent of this

unit.

Compiled by: Pat Green, Nez Perce National Forest, and Jim Mital, Clearwater

National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 28
LTA14-331A

VALLEYS: RECENT FINE ALLUVIUM

Location: This unit is located in the Palouse and Weippe Prairies of

north-central Idaho in the Clearwater, Palouse, and Hangman River Basins.

 Acreage by Section:

 14-331A 20,245

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a valley bottom

landscape setting, which is typically composed of floodplains, alluvial

basins, and stream terraces. Parent materials are recent, fine, alluvial

deposits primarily underlain by Columbia flood basalts and Belt metasediments.

Accessory Characteristics: The primary soils are deep to very deep with

moderately fine to fine textures. The vegetation is a mosaic of dry to moist

coniferous forest, riparian shrub communities, and mesic to wet meadows. Mean

annual precipitation ranges from 51 to 102 cms. (20 to 40 inches). The

elevation range is 762 to 1067 meters (2500 to 3500 feet). The dominant slopes

have gradients of 0 to 10 percent. This unit is moderately dissected by

streams, with the dominate stream pattern being dendritic. Wetlands and ponds

are a major component of this unit.

LTA Components: This landtype association consists of flood plains, alluvial

basins, and stream terraces.

Flood plains and alluvial basins are formed in moderately fine -textured recent

alluvium. Slope gradients range from 0 to 3 percent. Soils on these landforms

are deep, weakly to moderately developed, and consist mostly of silt loam and

silty clay loam textures. These soils are classified as Aquic Haploxerolls and

Aquic Xerofluvents. Rock outcrop occurs on less than 1 percent of this

landscape component. The dominant potential natural vegetation are mesic to

wet grass/sedge associations, willow/alder associations, and Douglas

fir/grand fir series. This component represents 80 percent of this unit.

Stream terraces are formed in mixed alluvium. Slope gradients range from 2 to

10 percent. Soils on these landforms are deep, weakly developed, and consist

mostly of medium to moderately fine textures. These soils are classified as

Fluvaquentic Haploxerolls and Fluventic Eutrochrepts. Rock outcrop occurs on

less than 1 percent of this landscape component. The dominant potential

natural vegetation series are ponderosa pine, Douglas -fir, and

willow/cottonwood associations. This component represents 20 percent of this

unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 29
LTA17-331A

HILLS AND PLATEAUS: LOESS

Location: This unit is located in west-central Idaho on the Palouse and Camas

Prairies.

 Acreage by Section:

 17-331A 855,787

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a low to mid

elevation, gently to moderately sloping landscape setting which is typically

composed of low relief rolling hills and plateaus. Parent materials are a

thick layer 2 to 81 meters (6 to 300 feet) thick of wind -blown loess underlain

primarily by Columbia flood basalts.

Accessory Characteristics: The primary soils are deep to very deep with silt

loam surface textures and silt loam to silty clay loam subsurface textures.

The vegetation is a mosaic of prairie grasslands with forest vegetation at the

higher elevations. Mean annual precipitation ranges from 38 to 76 cms. (15 to

30 inches). The elevation range is 305 to 914 meters (1000 to 3000 feet). The

dominant slopes have gradients of 0 to 30 percent. This unit is slightly to

moderately dissected by streams, with the dominate stream pattern being

dendritic. Wetlands are a minor component of this unit.

LTA Components: This landtype association consists of low relief rolling

hills, and plateaus.

Low relief rolling hills are formed in wind-blown loess exhibiting dune

formations, primarily in the Palouse Prairie near Moscow. Slope gradients

range from 5 to 30 percent. Soils on these landforms are deep to very deep,

highly developed, and consist of silt loam surface textures and silt loam and

silty clay loam subsurface textures. These soils are classified as Ultic

Argixerolls, Ultic Haploxeralfs, and Pachic Ultic Haploxerolls. Rock outcrop

are uncommon on this landscape component. The dominant potential natural

vegetation is bluebunch wheatgrass and Idaho fescue in the prairie grasslands

and ponderosa pine, Douglas-fir, and grand fir in forested areas. This

component represents 50 percent of this unit.

Plateaus are formed in wind-blown loess overlying volcanic residuum, primarily

in the Camas Prairie near Grangeville. Slope gradients range from 0 to 15

percent. Soils on these landforms are deep to very deep, highly developed, and

consist of silt loam surface textures and silt loam and silty clay loam

subsurface textures. These soils are classified as Ultic Argixerolls, Typic

Haploxeralfs, and Ultic Haploxerolls. Rock outcrop are uncommon on this

landscape component. The dominant potential natural vegetation isbluebunch

wheatgrass and Idaho fescue in the prairie grasslands and ponderosa pine and

Douglas-fir in forested areas. This component represents 50 percent of this

unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 30
LTA23-331A

BREAKS: SCHISTS AND GNEISSES

Location: This unit is located in the mainstem Clearwater River Valley of

Idaho, cutting through the foothills of the Clearwater Mountains near Orofino.

 Acreage by Section:

 23-331A 6,961

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a very steep, deeply

eroded landscape setting which is typically composed of stream or structural

breaks. Parent materials are moderately weathered gneisses and schists with a

variable thickness of wind-blown loess.

Accessory Characteristics: The primary soils are shallow to moderately deep

with textures ranging from silt loams to very gravelly loams. The vegetation

is a mosaic of coniferous forest with numerous rock outcrops and grassy

openings. Mean annual precipitation ranges from 64 to 89 cms (25 to 35

inches). The elevation range is 305 to 762 meters (1000 to 2500 feet). The

dominant slopes have gradients of 60 to 80 percent. This unit is moderately

dissected by streams, with the dominate stream pattern being parallel.

Wetlands are generally not present in this unit.

LTA Components: This landtype association consists primarily of stream breaks,

that sometimes formed along structural breaks.

Stream breaks are formed in colluvial materials from moderately weathered

gneisses and schists with a variable layer of loess mixed in the surface layer.

Slope gradients range from 60 to 80 percent. Soils on these landforms are

shallow to moderately deep, weakly developed with silt loam to loam surface

textures and very gravelly to cobbly subsurface textures. These soils are

classified as Typic Haploxerolls, Typic Xerochrepts, and Ultic Haploxerolls.

Rock outcrop occurs on 20 to 40 percent of this landscape component. The

dominant potential natural vegetation series are ponderosa pine, Douglas-fir,

and Idaho fescue. This component represents 100 percent of this unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 31
LTA24-331A

BREAKS: VOLCANICS

Location: This unit is located along the Potlatch and lower Clearwater River

Basins of west-central Idaho.

 Acreage by Section:

 24-331A 210,704

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a very steep, deeply

eroded landscape setting which is typically composed of stream breaks. Parent

materials are weakly to moderately weathered Columbia flood basalts overlain

with a variable thickness of wind-blown loess.

Accessory Characteristics: The primary soils are shallow to moderately deep

with textures ranging from silt loams to very cobbly loams. The vegetation is

a mosaic of grasslands with some shrubland inclusions. Mean annual

precipitation ranges from 33 to 64 cms. (13 to 25 inches). The elevation range

is 244 to 914 meters (800 to 3000 feet). The dominant slopes have gradients of

60 to 80 percent. This unit is moderately dissected by streams, with the

dominate stream pattern being parallel. Wetlands are generally not present in

this unit.

LTA Components: This landtype association consists primarily of stream breaks.

Stream breaks are formed in colluvial materials from weakly to moderately

weathered Columbia flood basalts with a variable layer of loess mixed in the

surface layer. Slope gradients range from 60 to 80 percent. Soils on these

landforms are shallow to moderately deep, weakly developed with silt loam to

loam surface textures and very gravelly to cobbly subsurface textures. These

soils are classified as Typic Haploxerolls, Lithic Argixerolls, and Ultic

Argixerolls. Rock outcrop occurs on 20 to 40 percent of this landscape

component. The dominant potential natural vegetation series are Idaho fescue,

bluebunch wheatgrass, and ponderosa pine in the moister settings. This

component represents 100 percent of this unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 32
LTA59-331A

MOUNTAIN SLOPES AND RIDGES: MODERATELY WEATHERED GNEISSES,

QUARTZITES AND SCHISTS

Location: This unit is located in mountains and canyons of north central Idaho

and central Idaho in the Clearwater River Basin.

 Acreage by Section:

 59-331A 2,671

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is colluvial mountain slopes.

Parent materials are moderately weathered gneiss, schist and quartzite

associated with the Idaho batholith.

Accessory Characteristics: The primary soils are deep to very deep silt loams,

loams and sandy loams. The vegetation is dominantly coniferous forest, with

some grassland at low elevations on south aspects. Mean annual precipitation

ranges from 64 to 114 centimeters (25 to 45 inches). The elevation range is

900 to 1500 meters (3000 to 5000 feet). The dominant slopes have gradients of

35 to 55 percent. This unit is moderately dissected by streams, with the

dominant stream pattern being parallel. 

LTA Components: This landtype association consists of mountain slopes.

Mountain slopes are formed in volcanic ash influenced loess, residuum and

colluvium of felsic lithology. Soils on these landforms are deep to very deep,

moderately developed silt loams, loams and sandy loams with sandy or loamy

substrata. Soils on low elevations on south aspects are Ultic Haploxerolls.

At mid elevations soils are classified as Andic Dystrochrepts and Typic

Dystrochrepts. Rock outcrop is less than 25 percent of the unit. The dominant

potential natural vegetation at low elevations is bluebunch wheatgrass, at mid

elevations, Douglas-fir and grand fir, and at high elevations subalpine fir.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 33
 LTA60-331A

MOUNTAIN SLOPES AND RIDGES: METASEDIMENTARY (BELT)

Location: This unit is located in the Palouse Prairie region and Hangman Creek

Basin of north Idaho.

 Acreage by Section

 60-331A 79,300

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a moderately sloping

mountain slope and ridge landscape setting, which is typically composed of

moderately dissected mountain slopes and ridgetops. Parent materials are a

mixed surface layer of Palouse loess and Mazama volcanic ash underlain by

colluvium and residuum of Precambrian Belt rocks such as argillite, quartzite,

and siltite.

Accessory Characteristics: The primary soils are moderately deep to deep with

silt loam to loam surface textures and very gravelly to cobbly loam subsurface

layers. The vegetation is a mosaic of prairie and coniferous forest. Mean

annual precipitation ranges from 64 to 102 cms (25 to 40 inches). The

elevation range is 914 to 1371 meters (3000 to 4500 feet). The dominant slopes

have gradients of 30 to 60 percent. This unit is moderately to highly

dissected by streams, with the stream pattern being dendritic to trellis.

Wetlands and moist seeps are a minor component of this unit.

LTA Components: This landtype association consists of steep mountain slopes,

and ridge tops.

Steep mountain slopes are formed in Belt colluvium overlain by a mixture of

Palouse loess and Mazama volcanic ash. Slope gradients range from 30 to 60

percent. Soils on these landforms are moderately deep to very deep, moderately

to highly developed, and consist of silt loam to loam surface textures with

gravelly loam subsurface textures. These soils are classified as Ultic

Haploxerolls, Typic Argixeralfs, and Andic Xerochrepts. Rock outcrop occurs on

about 5 percent of this landscape component. The dominant potential natural

vegetation is bluebunch wheatgrass and Idaho fescue in prairie areas and

ponderosa pine, Douglas-fir, and grand fir in forested settings. This

component represents 75 percent of this unit.

Ridgetops are formed in Belt residuum and colluvium overlain by a mixed layer

of Palouse loess and Mazama volcanic ash in some locations. Slope gradients

range from 15 to 40 percent. Soils on these landforms are shallow to deep,

moderately developed, and consist of silt loam to loam surface textures with

gravelly to cobbly loam subsurface textures. These soils are classified as

Typic Haploxerolls, Andic Xerochrepts, and Typic Argixeralfs. Rock outcrop

occurs on about 10 percent of this landscape component. The dominant potential

natural vegetation is bluebunch wheatgrass and Idaho fescue in prairie areas

and ponderosa pine, Douglas-fir, and grand fir in forested settings. This

component represents 20 percent of this unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 34
LTA61-331A

MOUNTAIN SLOPES AND RIDGES: HIGHLY WEATHERED GRANITICS

Location: This unit is located in the Palouse Prairie region of north Idaho.

 Acreage by Section

 61-331A 3,275

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a moderately sloping

mountain slope and ridge landscape setting, which is typically composed of

moderately dissected mountain slopes and ridgetops. Parent materials are a

mixed surface layer of Palouse loess and Mazama volcanic ash underlain by

highly weathered granitics of the Idaho Batholith.

Accessory Characteristics: The primary soils are moderately deep to deep with

silt loam to loam surface textures and very gravelly to cobbly loam subsurface

layers. The vegetation is a mosaic of prairie and coniferous forest. Mean

annual precipitation ranges from 64 to 102 cms. (25 to 40 inches). The

elevation range is 914 to 1158 meters (3000 to 3800 feet). The dominant slopes

have gradients of 30 to 60 percent. This unit is moderately to highly dissected

by streams, with the stream pattern being dendritic to trellis. Wetlands and

moist seeps are a common component of this unit.

LTA Components: This landtype association consists of steep mountain slopes,

and ridge tops.

Steep mountain slopes are formed in granitic colluvium overlain by Palouse

loess. Slope gradients range from 30 to 60 percent. Soils on these landforms

are moderately deep to very deep, moderately to highly developed, and consist

of silt loam to loam surface textures with gravelly loam subsurface textures.

These soils are classified as Ultic Haploxerolls, Typic Argixeralfs, and Typic

Xerochrepts. Rock outcrop occurs on about 5 percent of this landscape

component. The dominant potential natural vegetation is bluebunch wheatgrass

and Idaho fescue in prairie areas and ponderosa pine and Douglas-fir in

forested settings. This component represents 75 percent of this unit.

Ridgetops are formed in granitic residuum and colluvium overlain by a mixed

layer of Palouse loess. Slope gradients range from 15 to 40 percent. Soils on

these landforms are shallow to deep, moderately developed, and consist of silt

loam to loam surface textures with gravelly to cobbly loam subsurface

textures. These soils are classified as Typic Haploxerolls, Typic Xerochrepts,

and Typic Argixeralfs. Rock outcrop occurs on about 10 percent of this

landscape component. The dominant potential natural vegetation is bluebunch

wheatgrass and Idaho fescue in prairie areas and ponderosa pine and Douglas-fir

in forested settings. This component represents 20 percent of this unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 35
LTA62-331A

MOUNTAIN SLOPES AND RIDGES: WEAKLY WEATHERED GRANITICS

Location: This unit is located in the Clearwater Mountains of north central

Idaho in the Clearwater River Basin.

 Acreage by Section:

 62-331A 1,073

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a non-glaciated steep

mountain slope landscape setting, below the zone of strong frost shattering,

and is typically composed of moderately dissected mountain slopes, ridge tops,

and minor amounts of narrow valley bottoms. Parent materials are colluvium and

residuum underlain by weakly weathered granitic and gneissic bedrock.

Accessory Characteristics: The primary soils are deep, moderately coarse

textured, and have numerous rock fragments throughout the profile. The

vegetation is coniferous forest, with minor native grasslands on low elevation

south aspects. Annual precipitation ranges from 64 to 102 centimeters (25 to

40 inches). The elevation range is 750 to 1600 meters (2500 to 5300 feet).

The dominant slopes have gradients of 20 to 55 percent. This unit is

moderately dissected by streams. Low order streams are parallel and higher

order streams are dendritic in pattern. Wetlands are a minor component of this

unit.

LTA Components: This landtype association consists of mountain slopes and

ridge tops.

Mountain slopes are formed in colluvium and residuum. Slope gradients range

from 35 to 55 percent. Soils on this landform are moderately deep to deep and

well drained. These soils are moderately developed. On south aspects soils

have a loam or sandy loam surface layer that overlies very gravelly or very

cobbly sandy loam or loamy sand substrata. The dominant soils are classified

as Ultic Haploxerolls and Typic Dystrochrepts. On north aspects soils have a

thin surface layer of volcanic ash influenced loess. They are Andic

Dystrochrepts. Rock outcrop occurs on about 10 percent of this landscape

component. The dominant potential natural vegetation is Douglas-fir and grand

fir series and bluebunch wheatgrass. This component represents 80 percent of

this unit.

Mountain ridge tops are formed in residuum. Slope gradients range from 20 to

35 percent. Soils on this landform are moderately deep to deep and well

drained. Soil textures and degree of soil development are similar to those

listed above for south aspects. These soils are Ultic Haploxerolls and Typic

Dystrochrepts. Rock outcrop occurs on about 10 percent of this landscape

component. The dominant potential natural vegetation series are Douglas-fir

and grand fir. This component represents 15 percent of this unit.

Compiled by: Pat Green, Nez Perce National Forest, and Jim Mital, Clearwater

National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 36
LTA63-331A

 MOUNTAIN SLOPES AND RIDGES: SCHIST AND GNEISS

Location: This unit is located in the Clearwater Mountains of Idaho in the

Orofino and South Fork Clearwater River Basins.

 Acreage by Section

 63-331A 7,634

LTA Unit Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a moderately sloping

mountain slope and ridge landscape setting, which is typically composed of

moderately dissected mountain slopes and ridgetops. Parent materials are a

surface layer of Mazama volcanic ash underlain by schist and gneiss with high

amounts of mica.

Accessory Characteristics: The primary soils are moderately deep to very deep

with silt loam to loam surface textures and gravelly loam subsurface layers.

The vegetation is a mosaic of coniferous forest. Mean annual precipitation

ranges from 64 to 102 cms. (25 to 40 inches). The elevation range is 762 to

1068 meters (2500 to 3500 feet). The dominant slopes have gradients of 30 to

60 percent. This unit is moderately to highly dissected by streams, with the

stream pattern being dendritic to trellis. Wetlands and moist seeps are a

common component of this unit.

LTA Components: This landtype association consists of steep mountain slopes,

and ridge tops.

Steep mountain slopes are formed in schist and gneiss colluvium overlain by

Mazama volcanic ash. Slope gradients range from 30 to 60 percent. Soils on

these landforms are moderately deep to very deep, highly developed, and consist

of silt loam to loam surface textures with gravelly loam subsurface textures.

These soils are classified as Andic Dystrochrepts, Andic Xerochrepts, and

Vitric Hapludands. Rock outcrop occurs on about 5 per cent of this landscape

component. The dominant potential natural vegetation is western redcedar and

grand fir. This component represents 80 percent of this unit.

Ridgetops are formed in gneiss and schist residuum and colluvium overlain by a

mixed layer of Mazama volcanic ash. Slope gradients range from 15 to 50

percent. Soils on these landforms are shallow to deep, moderately to highly

developed, and consist of silt loam to loam surface textures with gravelly to

cobbly loam subsurface textures. These soils are classified as Andic

Dystrochrepts, Andic Xerochrepts, and Vitric Hapludands. Rock outcrop occurs

on about 10 percent of this landscape component. The dominant potential

natural vegetation is western redcedar, grand fir, and Douglas-fir. This

component represents 20 percent of this unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 37
LTA64-331A

MOUNTAIN SLOPES AND RIDGES: VOLCANICS

Location: This unit is located along streams and rivers, and adjacent to

basalt plateaus in west central Idaho in the Clearwater River Basin.

 Acreage by Section:

 64-331A 263,297

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is colluvial mountain slopes

and is usually is adjacent to steam breaklands or plateaus. Parent materials

are poorly to moderately weathered Columbia River basalt.

Accessory Characteristics: The primary soils are moderately deep to deep loams

and cobbly loams. The vegetation is a mosaic of grassland and coniferous

forest. Mean annual precipitation ranges from 30 to 89 centimeters (12 to 35

inches). The elevation range is 275 to 1700 meters (700 to 5800 feet). The

dominant slopes have gradients of 35 to 50 percent. This unit is moderately

dissected by streams, with the dominant stream pattern being parallel. 

LTA Components: This landtype association consists of mountain slopes.

Mountain slopes are formed in thin or mixed influenced loess, residuum and

colluvium of basalt lithology. Slope gradients range from 35 to 50 percent.

Soils on these landforms are moderately deep to deep, moderately developed

cobbly loams and loams with very cobbly loamy or clayey substrata. These soils

are classified as Ultic Argixerolls, with Andeptic Cryoboralfs at higher

elevations. Rock outcrop is less than 25 percent of the unit. The dominant

potential natural vegetation at low elevations is bluebunch wheatgrass series,

and at mid elevations Douglas-fir and grand fir series.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 38
LTA80-331A

LOW RELIEF HILLS: METASEDIMENTARY (BELT)

Location: This unit is located in the Clearwater Mountains of Idaho in the

Palouse River Basin.

 Acreage by Section

 80-331A 11,266

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a low to mid

elevation, gentle to moderately sloping, mountain sideslope and ridge landscape

setting, which is composed of highly dissected mountain slopes and associated

ridges comprised deeply weathered residuum. Parent materials are a mixture of

Palouse loess and Mazama volcanic ash overlying moderately to highly weathered

quartzites, and siltites from Precambrian metasedimentary bedrock.

Accessory Characteristics: The primary soils are deep silt loams and loams.

The vegetation is a mosaic of coniferous forest. Mean annual precipitation

ranges from 64 to 114 centimeters (25 to 45 inches). The elevation range of

this unit is 763 to 1220 meters (2500 to 4000 feet). The dominant slopes have

gradients of 10 to 30 percent. This unit is highly dissected, but many of the

dissections do not have live stream channels. The stream pattern is strongly

dendritic.

LTA Components: This landtype association consists of low relief rolling

hills.

Low relief rolling hills with gentle to moderately steep slopes and are formed

in metasediments that consist of quartzites, siltites and inclusions of schists

overlain by a mixture of Palouse loess and Mazama volcanic ash. The slope

gradients range from 10 to 40 percent. Soils on these landforms are deep,

moderately to highly weathered and medium textured. The major soils on the

well drained sites are classified as Ultic Haploxeralfs, Typic Udivitrands, and

Alfic Udivitrands. The dominant potential natural vegetation on the well

drained sites are western redcedar and grand fir. This component represents 90

percent of this unit.

Compiled by: Jim Mital, Clearwater National Forest and Jerry Niehoff, Idaho

Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 39
LTA81-331A

LOW RELIEF HILLS: HIGHLY WEATHERED GRANITICS

Location: This unit is located in the Clearwater Mountains of north central

Idaho in the Clearwater River Basin.

 Acreage by Section:

 81-331A 427

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a moderately steep,

highly dissected mountain slope landscape setting which is typically composed

of dissected slopes, ridge tops, and noses of spur ridges. Parent materials

are colluvium and residuum underlain by highly weathered granitic bedrock.

Accessory Characteristics: The primary soils are moderately deep to very deep

silt loams and fine sandy loams with sandy substrata. The vegetation is

coniferous forest. Mean annual precipitation ranges from 76 to 102 centimeters

(30 to 40 inches). The elevation range is 1250 to 1600 meters (4170 to 5300

feet). The dominant slopes have gradients of 10 to 45 percent. This unit is

highly dissected by streams, with the dominant stream pattern being dendritic.

Wetlands are a minor component of this unit.

LTA Components: This landtype association consists of dissected mountain

slopes.

Dissected mountain slopes are formed in residuum and colluvium derived from

highly weathered granitics. Slope gradients range from 10 to 45 percent.

Soils on this landform are moderately deep to deep and somewhat excessively to

well drained. These soils are poorly developed to moderately well developed

and consist of silt loam and fine sandy loam volcanic ash influenced loess

surface layers that overlie gravelly sandy loam to loamy sand or sand

substrata. The dominant soils are classified as Andic Dystrochrepts and Typic

Udivitrands. Rock outcrop occurs on about 5 percent of this landscape

component. The dominant potential natural vegetation is grand fir and western

redcedar series. This component represents 90 percent of this unit.

Compiled by: Pat Green, Nez Perce National Forest, and Jim Mital, Clearwater

National Forest.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 40
LTA82-331A

LOW RELIEF HILLS: VOLCANICS

Location: This unit is located in west-central Idaho in the Lower Salmon,

Snake, Lolo, and Orofino River Basins.

 Acreage by Section:

 

 82-331A 233,530

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a low to mid

elevation, gently to moderately sloping landscape setting which is typically

composed of low relief rolling hills and low mountains. Parent materials are

wind-blown loess and Mazama volcanic ash underlain by Columbia flood basalts.

Accessory Characteristics: The primary soils are deep to very deep with silt

loam and loam surface textures and gravelly silt loam to silty clay subsurface

textures. The vegetation is a mosaic of coniferous forest. Mean annual

precipitation ranges from 51 to 89 cms (20 to 35 inches). The elevation range

is 762 to 1372 meters (2500 to 4500 feet). The dominant slopes have gradients

of 5 to 30 percent. This unit is highly dissected by streams, with the

dominate stream pattern being dendritic. Wetlands are a minor component of

this unit.

LTA Components: This landtype association consists of low relief rolling

hills.

Low relief rolling hills are formed in Columbia flood basalt residuum overlain

by wind-blown loess and Mazama volcanic ash. Slope gradients range from 5 to

30 percent. Soils on these landforms are deep to very deep, highly developed,

and consist of silt loam and loam surface textures and silt loam to gravelly

silt loam and silty clay subsurface textures. These soils are classified as

Ultic Argixerolls, Ultic Haploxeralfs, and Andic Xerochrepts. Rock outcrop are

uncommon on this landscape component. The dominant potential natural

vegetation is grand fir, Douglas-fir, and western redcedar in the Lolo and

Orofino Creek Basins.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 41
LTA83-331A

LOW RELIEF HILLS: FINE TERTIARY SEDIMENTS

Location: This unit is located in west-central Idaho in the Lolo and Orofino

Creek Basins.

 Acreage by Section:

 83-331A 167,138

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a low to mid

elevation, gently to moderately sloping landscape setting which is typically

composed of low relief rolling hills and low mountains. Parent materials are

Mazama volcanic ash and wind-blown loess underlain by Tertiary alluvial

deposits.

Accessory Characteristics: The primary soils are deep to very deep with silt

loam surface textures and silt loam to silty clay subsurface textures. The

vegetation is a mosaic of coniferous forest. Mean annual precipitation ranges

from 64 to 89 cms. (25 to 35 inches). The elevation range is 762 to 1372 meters

(2500 to 4500 feet). The dominant slopes have gradients of 5 to 30 percent.

This unit is highly dissected by streams, with the dominant stream pattern

being dendritic. Wetlands are a minor component of this unit.

LTA Components: This landtype association consists of low relief rolling

hills.

Low relief rolling hills are formed in Tertiary alluvium overlain by Mazama

volcanic ash and wind-blown loess. Slope gradients range from 5 to 30

percent. Soils on these landforms are deep to very deep, highly developed, and

consist of silt loam surface textures and silt loam to silty clay subsurface

textures. These soils are classified as Ultic Haploxeralfs, Typic

Eutroboralfs, and Andic Xerochrepts. Rock outcrops are uncommon on this

landscape component. The dominant potential natural vegetation is grand fir,

Douglas-fir, and western redcedar.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 42
LTA84-331A

LOW RELIEF HILLS: HIGHLY WEATHERED SCHISTS

Location: This unit is located at middle elevations in north central Idaho in

the Clearwater River basin.

 Acreage by Section:

 84-331A 24,608

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is rolling uplands developed

in volcanic ash influenced loess and highly weathered residuum of Precambrian

schist.

Accessory Characteristics: The primary soils are very deep silt loams. The

vegetation is dominantly coniferous forest. Mean annual precipitation ranges

from 97 to 127 centimeters (38 to 45 inches). The elevation range is 1250 to

1600 meters (4167 to 5000 feet). The dominant slopes have gradients of 20 to

50 percent. This unit is highly dissected by streams, with the dominant stream

pattern being dendritic. Wetlands are a minor component of this map unit.

LTA Components: This landtype association consists of rolling hills.

Rolling hills are formed in volcanic ash influenced loess and schist

residuum. Soils on these landforms are very deep, moderately developed silt

loams with gravelly sandy loam substrata. These soils are classified a s Typic

Udivitrands. Rock outcrop is less than 10 percent of the unit. The dominant

potential natural vegetation is western red cedar and grand fir, with Sitka

alder communities in moist openings.

Compiled by: Pat Green, Nez Perce National Forest, and Jim Mital, Clearwater

National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 43
LTA90-331A

MASS WASTED SLOPES: MIXED GEOLOGY

Location: This unit is located in west-central Idaho in the South Fork

Clearwater River Basin.

 Acreage by Section:

 90-331A 2,621

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is mass wasted slopes. Parent

materials can be of any lithology, but in this Section they are dominantly

volcanics (Columbia flood basalts) overlain with a variable thickness of Mazama

volcanic ash.

Accessory Characteristics: The primary soils are deep to very deep silt loams

to cobbly loams. The vegetation is a mosaic of coniferous forest. Mean annual

precipitation ranges from 51 to 89 cms (20 to 35 inches). The elevation range

is 610 to 1219 meters (2000 to 4000 feet). The dominant slopes have gradients

of 30 to 60 percent. This unit is moderately dissected by streams, with the

dominant stream pattern being parallel to dendritic. Wetlands are a minor

component of this unit, but moist seeps can be locally common.

LTA Components: This landtype association consists of mass wasted slopes.

Mass wasted slopes are formed in mixed Mazama volcanic ash overlying Columbia

flood basalts. Slope gradients range from 30 to 60 percent. Soils on these

landforms are deep to very deep, weakly to moderately developed loams to cobbly

loams, sometimes with a clayey substrata. These soils are classified as Typic

Dystrocrepts, Ultic Argixerolls, and Andic Xerochrepts. Rock outcrops occurs

on less than 10 percent of this unit. The dominant potential natural

vegetation is ponderosa pine, Douglas-fir, and grand fir.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 44
CHAPTER 4

LTA Descriptions

Section M331A Yellowstone Highlands

This Section occurs in south-central Montana and northwest Wyoming. It

generally coincides with the Yellowstone Volcanic Plateau geomorphic area

previously described. Nineteen LTAs were mapped in this Section. See Appendix

F for a complete list of the LTAs and their acreages. The map unit descriptions

are preceded by the following illustrations.

 Figure 10: Map showing location of M331A within the Northern Region

 Figure 11: Section M331A landscape photograph.

 Northern Yellowstone National Park

 Figure 12: Map showing distribution of LTAS within M331A

 Figure 13: Bar chart showing abundance of landform groups within M331A

 Figure 14: Bar chart showing abundance of geologic groups within M331A

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 45
LTA10-M331Am

LTA10-M331Ap

LTA10-M332E

VALLEYS: RECENT COARSE ALLUVIUM

Location: This LTA is located in the Beaverhead, Anaconda Pintlar, Fleecer,

Pioneer, Lima, Tendoy, and Madison Ranges. These are in southwest Montana in

the Jefferson and Madison Basins.

 Acreage by Subsection/Section

 10-M331Am 5,925

 10-M331Ap 6,935

 10-M332E 88,247 (all of Section except M332En)

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a valley bottom and

alluvial fan landscape setting, which is typically composed of glaci al outwash

plains, stream terraces, and alluvial fans. Parent materials are

undifferentiated deposits of silts, sands, gravels, and cobble, which can be

underlain by any bedrock.

Accessory Characteristics: The primary soils are shallow to moderately deep,

gravelly loamy sands. The vegetation is a mosaic of deciduous shrubs,

deciduous forest, coniferous forest, upland grasslands, and wet meadow. Mean

annual precipitation ranges from 41 to 102 centimeters (16 to 40 inches). The

elevation range of this LTA is 1951 to 2804 meters (6400 to 9200 feet. The

dominant slope gradients are 0 to 15 percent. This LTA is slightly dissected

by streams, with the dominant stream pattern being dendritic. Wetlands are a

major component of this LTA.

LTA Components: This landtype association consists of glacial outwash plains,

stream terraces, and alluvial fans.

Glacial outwash fans are formed in relatively coarse alluvium. Slope gradients

range from 0 to 10 percent. Soils on these landforms are shallow to moderately

deep, poorly developed, well to excessively drained gravelly loamy sands and

sandy loams. Predominant soils are classified as Typic Cryochrepts. Rock

outcrop occurs on less than one percent of this landscape component. The

dominant potential natural vegetation is mountain big sagebrush and Idaho

fescue series. This component represents sixty percent of this land type

association. 

Stream terraces are formed in mixed alluvium and reworked glacial outwash.

Slope gradients range from 0 to 5 percent. Soils on these landforms are

shallow to moderately deep, poorly developed, well-drained gravelly loams and

sandy loams. Predominant soils are classified as Typic Cryorthents, and Typic

Cryochrepts. Rock outcrop does not occur in this unit. The dominant

potential natural vegetation is Douglas-fir and mountain big sage series. This

component represents 20 percent of this land type association.

Alluvial fans are formed in alluvium. Slope gradients range from 5 to 15

percent. Soils on these landforms are shallow, poorly developed, well drained

gravelly sandy loams. Predominant soils are classified as Typic Cryochrepts,

and Typic Cryoborolls. Rock outcrop does not occur in this unit. The dominant

potential natural vegetation is mountain big sage. This component represents

20 percent of this LTA.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 46
LTA10-M331A

VALLEYS: RECENT COARSE ALLUVIUM

Location: This unit is located in valley bottoms throughout the Gallatin

Forest and the Beartooth Mountains in the Custer National Forest in

southwestern Montana.

 Acreage by Section:

 10-M331A 31,149 (Section except M331Am and M331Ap)

LTA Setting and General Characteristics:

Differentiating Characteristics: This map unit consists of glacial outwash and

stream terraces, flood plains, alluvial fans, and bars in valley bottoms.

Parent material is relatively coarse textured stream alluvium.

Accessory Characteristics: Vegetation is sparse to dense Douglas-fir forest,

lower subalpine forest, grassland, meadow, and hardwood riparian communities.

Elevation ranges from 1525 to 2438 meters (5000 to 8000 feet). Mean annual

precipitation is 50 to 102 centimeters (20 to 40 inches). Slopes range from 0

to 10 percent.

LTA Components: This landtype association consists of two components:

Where vegetation is Douglas-fir forest, grassland, and hardwood riparian

communities, soils are Cryoborolls, Cryofluvents, and Cryaquolls. These soils

are moderately coarse textured, rocky, and have moderate fertility and water

holding capacity. Common potential vegetation includes Idaho fescue, big

sagebrush and Douglas-fir series along with various aspen, willow, and grass

communities in wet areas. This component makes up 70 percent of this LTA.

Where vegetation is lower subalpine forest, meadows, and hardwood riparian

communities, soils are Cryoborolls and Cryoboralfs. These soils are moderately

coarse to medium textured, rocky, and have moderate to high fertility and water

holding capacity. Common potential vegetation is subalpine fir and spruce.

This component makes up 30 percent of this LTA.

Compiled by: Henry Shovic, Gallatin National Forest and John R. Lane, Custer

National Forest.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 47
LTA12-M331A

LTA12-M332Db

LTA12-M332Dk

VALLEYS: OUTWASH AND OTHER OLDER COARSE ALLUVIAL

DEPOSITS

Location: This unit is located mostly in the Beartooth, southern Gallatin, and

Madison mountain ranges in southwestern Montana with smaller amounts in the

Bridger and Crazy Mountains.

 Acreage by Section:

 12-M331A 59,997

 12-M332Db 8,115

 12-M332Dk 41,445

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit consists of gently sloping

glacial outwash plains, alluvial fans, and terraces, with some landflows.

Parent material is coarse textured glaciofluvial deposits with some mixed loess

(wind blown silt) in the soils' surface layer.

Accessory Characteristics: Vegetation is dense lodgepole pine forest,

scattered Douglas-fir forest, or mountain grassland. Elevation ranges from

1560 to 2438 meters (5200 to 8000 feet). Mean annual precipitation is 38 to 81

centimeters (15 to 32 inches). Slope ranges from 0 to 40 percent.

LTA Components: This landtype association consists of two components:

Where vegetation is grassland, soils are Typic and Aridic Argiborolls with some

carbonatic soils such as Typic Cryoborolls, Calcic Cryoborolls, and Ustollic

Haplargids. These soils are deep, moderately coarse to medium textured, rocky,

and have moderate fertility and water holding capacity. Common potential

vegetation is big sagebrush and Idaho fescue series. This component makes up

40 percent of the LTA.

Where vegetation is lodgepole pine forest or Douglas-fir forest, soils are

Typic Cryochrepts or Typic Cryoboralfs. These soils are moderately coarse to

medium textured, rocky, and have very low to moderate fertility and water

holding capacity. A common potential vegetation is lodgepole pine near Hebgen

Lake in the Gallatin Range. This component makes up 60 percent of the LTA.

Compiled by: Henry Shovic, Gallatin National Forest and John R. Lane, Custer

National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 48
LTA14-M331A

LTA14-M332E

VALLEYS: RECENT FINE ALLUVIUM

Location: This LTA is located in the Beaverhead, Anaconda-Pintlar, Fleecer,

Pioneer, Lima, Tendoy, Gravelly, and Madison Ranges in southwest Montana in the

Jefferson and Madison Basins.

 Acreage by Section:

 14-M331A 12,271

 14-M332E 94,932

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in the larger valley bottoms,

which is typically composed of floodplains, glacio-fluvial wetlands, and

outwash alluvium. Parent materials are recent alluvium and glacio-fluvial

outwash deposits.

Accessory Characteristics: The primary soils are deep with fine textures and

organics. The vegetation is a mosaic of riparian deciduous and coniferous

forest, riparian shrub meadows and sedge meadows. Mean annual precipitation

ranges from 50 to 102 centimeters (20 to 40 inches). The elevation range of

this LTA is 2073 to 2896 meters (6800 to 9500 feet). The dominant slopes have

gradients of 0 to 10 percent.

This LTA is highly dissected by streams, with the dominant stream pattern being

dendritic. Wetlands are a major component of this LTA.

LTA Components: This landtype association consists of floodplains,

glaciofluvial wetlands, and outwash alluvium.

The floodplains are formed in variable alluvium, typically finer and/or organic

nearer the surface. Slope gradients range from less than one to four percent.

Soils on these landforms are typically deep, weakly to moderately developed,

poorly drained sands to silt, often with organic surface soils. These soils

are classified as Histic Cryaquolls and Aquic Cryoborolls. Rock outcrop does

not occur. The potential natural vegetation is a variety of riparian/wetland

communities such as willows and sedges. This component represents about 50

percent of this LTA.

Alluvial wetlands are formed in relatively fine glacial outwash and sediments,

in glaciofluvial valley fill deposits. Slope gradients range from 1 to 10

percent. Soils on these landforms are deep, poorly drained, weakly to

moderately developed, silt loams and silty clay loams, often with organic

surface soils. These soils are classified as Histic Cryaquolls and Aquic

Cumulic Cryoborolls. Rock out crop does not occur in these wetlands, but do

occur in the intermingled uplands. The dominant potential natural vegetation

is tufted hairgrass. This component represents about 30 percent of this LTA. 

Outwash alluvium is formed in glacial outwash and mixed alluvium and glacial

outwash. Slope gradients range from 1 to 15 percent. Soils on these landforms

are deep organic soils and deep, poorly drained silt loams and sandy loams.

These soils are classified as Sapric Terric Medihemists and Oxyaquic

Cryoborolls. Rock outcrop does not occur in this unit. The dominant potential

natural vegetation is comprised of various willow and wet meadow communities

such as willows and sedges. This component represents about 20 percent of this

LTA.

Compiled by: Dan Svoboda, Beaverhead-DeerLodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 49
LTA23-M331A

LTA23-M332E

BREAKS: SCHISTS AND GNEISSES

Location: This LTA is located in the Lima Peaks, Tendoy, Tobacco Root,

Gravelly, and Madison mountain ranges of the Beaverhead National Forest. It

occurs in southwest Montana in the Jefferson and Madison Basins.

 Acreage by Section:

 23-M331A 25,231

 23-M332E 23,278

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a steep, deeply eroded

(rejuvenated), or faulted mountainous landscape settings which is typically

composed of structural and stream breaklands. Parent materials are colluvium

and residuum derived from Pre-Belt crystalline metamorphic rocks consisting of

hornblende gneiss, quartzite, meta-diabase, sillimanite schist, quartz-feldspar

gneiss, metamorphosed granite and migmatite, including the Dillon

Granite-Gneiss in the Tendoy Mountains.

Accessory Characteristics: The primary soils are very shallow to moderately

deep, well drained, channery sandy loams and loams. The vegetation is a mosaic

of coniferous forest and mountain grasslands. Mean annual precipitation ranges

from 41 to 102 centimeters (16 to 40 inches). The elevation range of this LTA

is 2012 to 3048 meters (6600 to 10000 feet). The dominant slopes have

gradients of 40 to 75 percent. This LTA is highly to moderately dissected by

streams, with the dominant stream pattern being dendritic to parallel.

Wetlands, lakes, and ponds are not a component of this LTA. 

LTA Components: This landtype association consists of breaks.

Breaks are formed in colluvium and residuum. Slope gradients range from 40 to

75 percent. Soils on these landforms are very shallow to moderately deep,

well-drained, weakly developed channery sandy loams to loams. These soils are

classified as Lithic and Typic Cryorthents, and Lithic and Typic Cryochrepts.

Rock outcrop occurs on about 25 percent of this landscape component. The

dominant potential natural vegetation is Douglas-fir, big sagebrush, subalpine

fir and whitebark pine series. This component represents 100 percent of LTA.

Compiled by: Dan Svoboda, Beaverhead/Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 50
LTA25-M331A

LTA25-M332D

BREAKS: SANDSTONES AND SHALES

Location: This unit is located in the Beartooth, Bridger, Crazy, Gallatin and

Madison mountain ranges in southwestern Montana.

 Acreage by Section:

 25-M331A 69,798

 25-M332D 20,570

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit consists of steep to moderately

steep ridges and slopes whose shape is controlled by underlying bedrock

structure. Soil parent material is colluvium and residuum derived from thickly

interbedded limestone, sandstone, and shale.

Accessory Characteristics: Vegetation is sparse to dense forest with some

meadows and grassland. Elevation ranges from 1830 to 2640 meters (6000 to 8800

feet). Mean annual precipitation is 58 to 127 cms. (23 to 50 inches). Slopes

are greater than 40 percent.

LTA Components: This landtype association consists of two components:

Where vegetation is sparse Douglas-fir forest and grasslands, soils are Argic

Cryoborolls and Mollic Cryoboralfs. These soils are medium to moderately fine

textured, rocky or non-rocky, with moderate to high fertility and water holding

capacity. Where bedrock is limestone, soils are Lithic and Typic Calciborolls,

and Calcic Cryoborolls. Rock outcrop makes up 10 to 25 percent of this

component. Common potential vegetation includes Douglas-fir, Idaho fescue, and

big sagebrush series. This component makes up 50 percent of this LTA.

Where vegetation is dense forest and meadows, soils are Mollic and Typic

Cryoboralfs, Typic Cryochrepts, and Argic Cryoborolls. These soils are medium

to moderately fine textured, rocky or non-rocky, and have moderate fertility

and water holding capacity. Rock outcrop makes up 10 to 25 percent of this

component. Common potential vegetation includes Douglas-fir, subalpine fir,

Idaho fescue and subalpine fir-whitebark pine series. This component makes up

50 percent of this LTA.

Compiled by: Henry Shovic, Gallatin National Forest and John R. Lane, Custer

National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 51
LTA27-M331A

LTA27-M332E

 BREAKS: CARBONATES

Location: This LTA is located in the Lima Peaks, Tendoy, Pioneer, Fleecer,

Tobacco Root, Gravelly, and Madison mountain ranges in the Beaverhead National

Forest. It occurs in southwest Montana in the Jefferson and Madison Basins.

 Acreage by Section:

 27-M331A 6,506

 27-M332E 62,706

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a steep, deeply eroded

(rejuvenated), or faulted mountainous landscape setting which is typically

composed of structural and stream breaklands. Parent materials are collumium

and residuum derived largely from volcanics and limestone rocks of various

ages.

Accessory Characteristics: The primary soils are shallow to moderately deep,

well-drained channery loams. The vegetation is a mosaic of mountain grasslands

and open coniferous forest. Mean annual precipitation ranges from 41 to 102

centimeters (16 to 40 inches). The elevation range of this LTA is (2012 to

2591 meters (6600 to 8500 feet). The dominant slopes have gradients of 55 to

75 percent. This LTA is moderately to highly dissected by streams, with the

dominant stream pattern being dendritic to parallel. Wetlands and seeps are a

minor component of this LTA.

LTA Components: This landtype association consists of breaks. 

Breaks are formed in colluvium and residuum. Slope gradients range from 45 to

85 percent. Soils on these landforms are shallow, well drained, weakly

developed, channery loams. These soils are classified as Lithic and Typic

Cryochrepts. Rock outcrop occurs on about one third of this landscape

component. The dominant potential natural vegetation is low sagebrush,

curlleaf mountain mahogany, and Douglas-fir series. This component represents

100 percent of this LTA.

Compiled by: Dan Svoboda, Beaverhead/DeerLodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 52
LTA34-M331A

HIGH RELIEF MOUNTAIN SLOPES: VOLCANICS

Location: This unit is located in the Gallatin and Madison mountain ranges in

southwestern Montana.

 Acreage by Section:

 34-M331A 93,405

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit consists of steep mountain

slopes and ridges. Soil parent material is colluvium and residuum derived from

andesitic volcanic rocks.

Accessory Characteristics: Vegetation is dense to sparse lower subalpine

forest, Douglas-fir forest, or mountain grassland. Elevation ranges from 1981

to 2591 meters (6500 to 8500 feet). Mean annual precipitation is 75 to 100

centimeters (30 to 40 inches). Slopes range from 30 to 60 percent.

LTA Components: This landtype association consists of two components.

Soils in sparse to dense lower subalpine forest with some Douglas-fir forest

are Mollic Cryoboralfs. They are deep to moderately shallow, medium to

moderately fine textured, rocky, and have moderate to high fertility and water

holding capacity. Rock outcrop makes up 10 to 40 percent of this component.

Common potential vegetation includes subalpine fir and Douglas-fir series.

This component makes up 60 percent of this LTA.

Soils in sparse to dense Douglas-fir forest and grasslands are Pachic

Argiborolls, Mollic Eutroboralfs, and Typic Argiborolls. They are deep,

moderately coarse to moderately fine textured, rocky, and have moderate to high

fertility and water holding capacity. Rock outcrop makes of 15 percent of this

component. Common potential vegetation includes Douglas-fir, big sagebrush,

and Idaho fescue series. This component makes up 40 percent of this LTA.

Compiled by: Henry Shovic, Gallatin National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 53
LTA36-M331A

HIGH RELIEF MOUNTAIN SLOPES: SANDSTONES AND SHALES

Location: This unit is located in the Beartooth, Gallatin, Bridger, and

Madison mountain ranges in southwestern Montana.

 Acreage by Section:

 36-M331A 75,189

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit consists of steep mountain

slopes and ridges. Soil parent material is colluvium and residuum derived from

relatively soft interbedded sandstone and shale and lahars of the Livingston

Group.

Accessory Characteristics: Vegetation is dense to sparse lower subalpine

forest, Douglas-fir forest, or mountain grassland. Elevation ranges from 1676

to 2438 meters (5500 to 8000 feet). Mean annual precipitation is 53 to 69 cm.

(21 to 27 inches). Slopes range from 20 to 90 percent.

LTA Components: This landtype association has two components:

Soils in sparse to dense lower subalpine forest are Cryoboralfs and

Cryochrepts. They are deep to moderately shallow, moderately coarse to

moderately fine textured, rocky, and have low to moderate fertility and water

holding capacity. Rock outcrop makes up 15 percent of this component. A

common potential vegetation is the subalpine fir series. This component makes

up 70 percent of this LTA.

Soils in sparse to dense Douglas-fir forest and grasslands are Lithic

Haploborolls, Typic Ustochrepts, and Typic Argiborolls. They are deep,

moderately coarse to moderately fine textured, rocky or non-rocky, and have low

to moderate fertility and water holding capacity. Rock outcrop makes of 15

percent of this component. Common potential vegetation includes Douglas-fir

and Idaho fescue series. This component makes up 30 percent of this LTA.

Compiled by: Henry Shovic, Gallatin National Forest and John R. Lane, Custer

National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 54
LTA37-M331A

HIGH RELIEF MOUNTAIN SLOPES: CARBONATES

Location: This LTA is located in the Beartooth Mountains of southwest Montana.

 Acreage by Section:

 37-M331A 33,733

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a mountain landscape

setting dissected by streams, which is typically composed of mountain slopes

and dipslopes. Parent materials are gravelly and cobbly residuum and colluvium

underlain by limestone and some sandstone and shale.

Accessory Characteristics: The primary soils are shallow to deep, with cobbly

and channery medium and moderately coarse textures. The vegetation is a mosaic

of coniferous forest, and mountain grasslands. Mean annual precipitation

ranges from 58 to 89 cms (23 to 35 inches). The elevation range is 1830 to

2500 meters (6000 to 8200 feet). The dominant slopes have gradients of 40 to

90 percent. This unit is moderately dissected by streams, with the dominant

stream pattern being dendritic. 

LTA Components: This landtype association consists of mountain slopes and

dipslopes.

Mountain slopes are formed in colluvial and residual limestone material. Slope

gradients range from 20 to 90 percent. Soils on these landforms are shallow to

deep, weakly developed, channery medium textures. These soils are classified

as Lithic Calciborolls, Typic Calciborolls, and Calcic Cryoborolls. Rock

outcrop occurs on about 30 percent of this landscape component. The dominant

potential natural vegetation is subalpine fir and Douglas-fir series. This

component represents 60 percent of this unit.

Dipslopes are formes in colluvial and residual limestone material. slope

gradients range from 20 to 90 percent. Soils on these landforms are shallow to

deep, moderately developed, medium and moderately fine textured. These soils

are classified as Calcic Cryoborolls, Lithic Calciborolls, and Argic

Cryoborolls. Rock outcrop occurs on about 10 percent of this landscape

component. The dominant potential natural vegetation is limber pine, subalpine

fir and Douglas-fir series. This component represents 40 percent of this unit.

Compiled by: John R. Lane, Custer National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 55
LTA39-M331A

STEEP GLACIATED MOUNTAIN SLOPES: GNEISSES AND SCHISTS

Location: This LTA is located in the Beartooth Mountains of southwest Montana.

 Acreage by Section:

 39-M331A 150,081

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a glaciated mountain

landscape setting, which is typically composed of cirques, and troughs. Parent

materials are gravelly and cobbly residuum and colluvium underlain by gneiss

and schist bedrock.

Accessory Characteristics: The primary soils are shallow to deep, with medium

and coarse textures. The vegetation is a mosaic of coniferous forest. Mean

annual precipitation ranges from 53 to 140 cms. (21 to 55 inches). The

elevation range is 1675 to 3200 meters (5500 to 10500 feet). The dominant

slopes have gradients of 40 to greater than 90 percent. This unit is

moderately dissected by streams, with the dominant stream pattern being

dendritic. 

LTA Components: This landtype association consists of cirques and troughs.

Cirques are formed in colluvial and residual gneiss and schist material. Slope

gradients range from 70 to greater than 100 percent. Soils on these landforms

are shallow to deep, weakly developed, coarse textured. These soils are

classified as Typic Cryorthents, Lithic Cryorthents, and Typic Cryochrepts.

Rock outcrop occurs on about 60 percent of this landscape component. The

dominant potential natural vegetation is subalpine fir and Douglas-fir series.

Tree canopies are often stunted and deformed, existing as Krummholz pattern

above 8800 feet. This component represents 50 percent of this unit.

Troughs are formed in colluvial and residual gneiss and schist material. Slope

gradients range from 50 to 90 percent. Soils on these landforms are shallow to

deep, weakly developed, medium and coarse textured. These soils are classified

as Typic Cryorthents, Lithic Cryorthents, and Lithic Cryochrepts. Rock outcrop

occurs on about 50 percent of this landscape component. The dominant potential

natural vegetation is Douglas-fir, limber pine and subalpine fir. Tree

canopies are often stunted and deformed, existing as Krummholz pattern above

8800 feet. This component represents 50 percent of this unit.

Compiled by: John R. Lane, Custer National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 56
LTA40-M331A

LTA40-M332E

STEEP GLACIATED MOUNTAIN SLOPES: METASEDIMENTARY (BELT)

Location: This LTA is located in the Lima Peaks, Pioneers, Beaverhead, and

Madison mountain ranges in the Beaverhead National Forest in southwest Montana

in the Jefferson and Madison Basins.

 Acreage by Section:

 40-M331A 626

 40-M332E 100,569

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a steep, glacial

landscape setting which is typically composed of glacial headwalls and

troughwalls. Narrow, V-shaped trough valley bottoms and cirque basins are

described under LTA 50. Parent materials are metamorphosed sediments of the

Precambrian Y Belt Supergroup undifferentiated, consisting of fine to coarse

grained quartzite, siltite, argillite, carbonate, and sandstone.

Accessory Characteristics: The primary soils are shallow, flaggy, cobbly, or

gravelly loamy sands and sandy loams. The vegetation is a mosaic of coniferous

forest, alpine turf, and rockland. Mean annual precipitation ranges from 41 to

102 centimeters (16 to 40 inches). The elevation range of this LTA is 2256 to

3231 meters (7400 to 10600 feet). The dominant slopes have gradients of 50 to

70 percent. This LTA is highly to moderately dissected with the dominant

pattern being parallel. Wetlands/seeps are a minor component of this LTA.

LTA Components: This landtype association consists of cirque headwalls and

troughwalls. 

Headwalls are formed in metasediment bedrock. They usually have well developed

avalanche chutes and rock glaciers/scree. Slope gradients range from 50 to 90

percent. Soils on these landforms are very shallow, weakly developed, flaggy

loamy sands and loams. These soils are classified as Lithic and Typic

Cryorthents, and Lithic and Typic Cryochrepts. Rock outcrop occurs on about 75

percent of this landscape component. The dominant potential natural vegetation

is whitebark pine, and whitebark pine-subalpine fir series. This landform

component represents about 15 percent of this LTA.

Troughwalls are formed in metasediment bedrock. They have thin to thick till

deposits, and often have developed avalanche chutes. S lope gradients range from

45 to 70 percent. Soils on these landforms are shallow to moderately deep,

weakly to moderately developed, gravelly and cobbly loamy sands, sandy loams,

and loams. These soils are classified as Lithic and Typic Cryochrepts, and

Entic and Typic Cryumbrepts. Rock outcrop occurs on about 35 percent of this

landscape component. The dominant potential natural vegetation is whitebark

pine-subalpine fir, and subalpine fir series. This landform component

represents about 85 percent of this LTA.

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 57
LTA41-M331A

LTA41-M332Dc

STEEP GLACIATED MOUNTAIN SLOPES: GRANITICS

Location: This unit is located in the Gallatin and Crazy mountain ranges in

southwestern Montana.

 Acreage by Section:

 41-M331A 117,326

 41-M332Dc 72,095

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit consists of steep glacial

troughwalls with weak stream dissection. Included are some talus slopes and

rock glaciers. Soil parent material is colluvium and glacial till derived from

shallow, coarse grained, hard intrusive rocks.

Accessory Characteristics: Vegetation is sparse to dense upper subalpine,

lower subalpine, or Douglas-fir forest. Elevation ranges from 1768 to 2743

meters (5800 to 9000 feet). Mean annual precipitation is 63 to greater than

125 centimeters (25 to greater than 50 inches). Slopes are greater than 40

percent.

LTA Components: This landtype association has two components:

Soils where vegetation is either Douglas-fir or lower subalpine forest are Udic

Ustochrepts or Dystric Cryochrepts. These soils are deep, moderately coarse to

coarse textured, rocky, and have low fertility and water holding capacity.

Rock outcrop makes up 20 to 30 percent of this component. Common potential

vegetation includes subalpine fir and Douglas-fir series. This component makes

up 35 percent of this LTA.

Soils where vegetation is sparse upper subalpine forest or nearly absent are

Cryochrepts. They are deep to shallow, and generally coarse textured with very

low fertility and water holding capacity. Rock outcrop makes up 50 to 90

percent of this component. Where forested, a common potential vegetation is

subalpine fir-whitebark pine series. This component makes up 65 percent of this

LTA.

Compiled by: Henry Shovic, Gallatin National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 58
LTA42-M331A

STEEP GLACIATED MOUNTAIN SLOPES: VOLCANICS

Location: This unit is located in the Gallatin and Absaroka-Beartooth mountain

ranges in southwestern Montana.

 Acreage by Section:

 42-M331A 60,666

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit consists of steep glacial

troughwalls with weak stream dissection. Soil parent material is colluvium and

glacial till derived from andesitic volcanic rocks.

Accessory Characteristics: Vegetation is sparse to dense lower subalpine or

Douglas-fir forest intermixed with meadows. Elevation ranges from 2316 to 2591

meters (7600 to 8500 feet). Mean annual precipitation is 75 to greater than

125 centimeters (30 to greater than 50 inches). Slopes are greater than 40

percent.

LTA Components: This landtype association has one component:

Soils are Typic Cryochrepts. These soils are deep, moderately coarse textured,

rocky, and have low fertility and water holding capacity. Rock outcrop makes

up 25 percent of this component. Common potential vegetation includes

subalpine fir and Douglas-fir series.

Compiled by: Henry Shovic, Gallatin National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 59
LTA43-M331A

STEEP GLACIATED MOUNTAIN SLOPES: CARBONATES

Location: This unit is located in the Bridger, Gallatin and Madison mountain

ranges in southwestern Montana.

 Acreage by Section:

 43-M331A 42,458

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit consists of steep glacial

troughwalls and hogback ridges with weak stream dissection. Soil parent

material is colluvium and glacial till derived from limestone with some

interbedded sandstone and shale.

Accessory Characteristics: Vegetation is sparse to dense forest with some

meadows and grassland. Elevation ranges from 1768 to 2682 meters (5800 to 8800

feet). Mean annual precipitation is 75 to 125 centimeters (30 to 50 inches).

Slope is greater than 40 percent.

LTA Components: This landtype association has one component:

Soils are Typic Argiborolls, Typic Calciborolls, Typic Cryochrepts, Typic

Cryoboralfs, and other Cryochrepts and Cryoborolls. These soils are medium to

moderately coarse textured, rocky, and have medium to low fertility and water

holding capacity. Rock outcrop makes up 15 to 60 percent of this component.

Common potential vegetation includes Idaho fescue, big sagebrush, subalpine

fir, and subalpine fir-whitebark pine series.

Compiled by: Henry Shovic, Gallatin National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 60
LTA44-M331A

STEEP GLACIATED MOUNTAIN SLOPES: SANDSTONE AND SHALE

Location: This unit is located in the Gallatin and Madison mountain ranges in

southwestern Montana.

 Acreage by Section:

 44-M331A 17,976

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit consists of steep glacial

troughwalls with weak stream dissection. Soil parent material is colluvium and

glacial till derived from interbedded sandstone and shale.

Accessory Characteristics: Vegetation is dense lower subalpine forest

intermixed with meadows. Elevation ranges from 2316 to 2591 meters (7600 to

8500 feet). Mean annual precipitation is 75 to greater than 125 centimeters

(30 to greater than 50 inches). Slopes are greater than 40 percent.

LTA Components: This landtype association has one component:

Soils are Typic Cryoboralfs and Typic Cryochrepts. These soils are moderately

fine to moderately coarse textured, rocky or non-rocky, and have medium to low

fertility and water holding capacity. Rock outcrop makes up 20 percent of this

component. Common potential vegetation includes subalpine fir and Idaho fescue

series.

Compiled by: Henry Shovic, Gallatin National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 61
LTA51-M331A

LTA51-M332D

LTA51-M332E

GLACIATED MOUNTAIN SLOPES: GRANITICS

Location: This unit is located in the Gallatin, Madison, Crazy, and

Absaroka-Beartooth mountain ranges in southwestern Montana.

 Acreage by Section:

 51-M331A 760

 51-M332D 98,809

 51-M332E 125,884

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit consists of gently to

moderately steep glacial moraine. Soil parent material is glacial till derived

from coarse grained, shallow, hard intrusive rocks.

Accessory Characteristics: Vegetation is sparse to dense upper to lower

subalpine forest, Douglas-fir forest, or mountain grassland. Elevation ranges

from 1981 to 2743 meters (6500 to 9000 feet). Mean annual precipitation is 50

to greater than 125 centimeters (20 to greater than 50 inches). Slopes range

from 0 to 40 percent.

LTA Components: This landtype association has three components:

Where vegetation is grassland, soils are Typic Cryoborolls and Argic

Cryoborolls. These soils are deep, moderately coarse to medium textured,

rocky, and have moderate fertility and water holding capacity. Rock outcrop

makes up five percent of this component. Common potential vegetation includes

big sagebrush and Douglas-fir. This component makes up 15 percent of the LTA.

Where vegetation is lower subalpine forest with some Douglas-fir forest, soils

are Typic Cryochrepts. These soils are moderately coarse texture, rock, and

have low fertility and water holding capacity. Rock outcrop makes up 10

percent of this component. Common potential vegetation includes subalpine fir

with some Douglas-fir. This component makes up 50 percent of the LTA.

Where vegetation is upper subalpine forest, soils are Cryochrepts intermixed

with some Cryumbrepts. These soils are deep to moderately shallow, rocky, and

have low fertility and water holding capacity. Rock outcrop makes up 20 to 40

percent of this component. Common potential vegetation includessubalpine

fir-whitebark pine, and Idaho fescue series. This component makes up 35

percent of the LTA.

Compiled by: Henry Shovic, Gallatin National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 62
LTA53-M331A

GLACIATED MOUNTAIN SLOPES: SANDSTONES AND SHALES

Location: This unit is located in the Madison and Absaroka-Beartooth mountain

ranges in southwestern Montana.

 Acreage by Section:

 53-M331A 76,853

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit consists of gently to

moderately steep glacial moraine. Soil parent material is glacial till derived

from interbedded sandstone and shale.

Accessory Characteristics: Vegetation is sparse to dense upper to lower

subalpine forest or mountain grassland. Elevations range from 2134 to 2591

meters (7000 to 8500 feet). Mean annual precipitation is 75 to 100 centimeters

(30 to 40 inches). Slopes range from 0 to 40 percent.

LTA Components: This landtype association has two components:

Where vegetation is grassland, soils are Argic Cryoborolls. These soils are

deep, medium to moderately fine textured, rocky, and have moderate to high

fertility and water holding capacity. Rock outcrop makes up zero to five

percent of this component. Common potential vegetation includes big sagebrush

and Idaho fescue series. This component makes up 40 percent of the LTA.

Where vegetation is upper or lower subalpine forest, soils are Typic and Mollic

Cryoboralfs. These soils are medium textured, rocky, and have moderate

fertility and water holding capacity. Rock outcrop makes up zero to five

percent of this component. Common potential vegetation includes subalpine fir,

and subalpine fir-whitebark pine series. This component makes up 60 percent of

the LTA. This component makes up 60 percent of the LTA.

Compiled by: Henry Shovic, Gallatin National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 63
LTA54-M331A

GLACIATED MOUNTAIN SLOPES: VOLCANICS

Location: This unit is located in the Gallatin and Absaroka-Beartooth mountain

ranges in southwestern Montana.

 Acreage by Section:

 54-M331A 87,011

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit consists of gently to

moderately steep glacial moraine. Soil parent material is glacial till derived

from andesitic or rhyolitic volcanic rocks.

Accessory Characteristics: Vegetation is sparse to dense upper subalpine or

lower subalpine forest. Elevation ranges from 2195 to 2743 meters (7200 to

9000 feet). Mean annual precipitation is 75 to greater than 125 centimeters

(30 to greater than 50 inches). Slopes range from 0 to 40 percent.

LTA Components: This landtype association has two components:

Where glacial till is derived from andesitic rock types, soils are Mollic

Cryoboralfs. These soils are deep, medium textured, rocky, and have moderate

fertility and water holding capacity. Rock outcrop makes up from 10 to 25

percent of this component. Common potential vegetation includes subalpine fir,

subalpine fir-whitebark pine, and Idaho fescue series. This component makes up

40 percent of the LTA.

Where glacial till is derived from rhyolitic rock types, soils are Typic

Cryochrepts. There is a thin layer of loess (wind blown silt) mixed in with the

surface layer of these soils. These soils are deep, moderately coarse

textured, rocky, and have low to moderate fertility and water holding

capacity. Rock outcrop makes up from 0 to 5 percent of this component. A

common potential vegetation series is subalpine fir. This component makes up

60 percent of the LTA.

Compiled by: Henry Shovic, Gallatin National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 64
LTA57-M331A

LTA57-M332D

GLACIATED MOUNTAIN SLOPES: GNEISSES AND SCHISTS

Location: This LTA is located mostly in the Beartooth Mountains of southwest

Montana. A very small acreage occurs in the Bridger Range.

 Acreage by Section:

 57-M331A 177,582

 57-M332D 569

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a glaciated mountain

landscape setting, which is typically composed of moraines. Parent materials

are very bouldery glacial till underlain by weakly metamorphosed gneiss and

schist bedrock. In the Bridger Range this unit consists mostly of weakly

metamorphosed granite.

Accessory Characteristics: The primary soils are deep, with very bouldery

medium to moderately coarse textures. The vegetation is a mosaic of coniferous

forest. Mean annual precipitation ranges from 55 to 114 cms. (22 to 50

inches). The elevation range is 1675 to 2743 meters (5500 to 9000 feet). The

dominant slopes have gradients of 0 to 80 percent.

LTA Components: This landtype association consists of ground moraines in

grassland, ground moraine in forest, and lateral moraines.

Ground moraines are formed in glacial till developed from gneiss and schist

material. Slope gradients range from 5 to 20 percent. Forested soils on these

landforms are shallow to deep, weakly developed, and very bouldery medium to

moderately coarse textured. These soils are classified as Typic Cryumbrepts,

Typic Cryochrepts, Typic Cryofluvents, and Lithic Cryorthents. The dominant

potential natural vegetation is Douglas-fir, limber pine and subalpine fir.

This component represents 70 percent of this unit.

Ground moraines in grassland are formed in glacial till developed from gneiss

and schist with some probable addition of loess. Soils are Typic Cryoborolls,

and Argic Cryoborolls. They are moderately coarse to medium textured, deep,

and moderately fertile. The dominant potential natural vegetation is Idaho

fescue and bluebunch wheatgrass. Rock outcrop makes up 5 percent of the unit.

This component represents 15 percent of this unit.

Lateral moraines are formed in glacial till developed from gneiss and schist

material. Slope gradients range from 50 to 80 percent. Soils on these

landforms are shallow to deep, moderately developed, medium and moderately fine

textured. These soils are classified as Typic Cryoborolls, Typic Cryochrepts,

and Typic Cryoboralfs. Rock outcrop occurs on about 10 percent of this

landscape component. The dominant potential natural vegetation is Douglas-fir

and subalpine fir. This component represents 15 percent of this unit.

Compiled by: John R. Lane, Custer National Forest and Henry Shovic, Gallatin

National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 65
LTA62-M331A

MOUNTAIN SLOPES AND RIDGES: WEAKLY WEATHERED GRANITICS

Location: This unit is located in the Gallatin, Madison, and

Absaroka-Beartooth mountain ranges in southwestern Montana.

 Acreage by Section:

 62-M331A 15,110

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit consists of a complex of

mountain slopes and ridges. Soil parent material is colluvium and residuum

derived from hard crystalline rocks such as granite.

Accessory Characteristics: Vegetation is dense lower subalpine forest or

mountain grassland. Elevation ranges from 1981 to 1987 meters (6500 to 9800

feet). Mean annual precipitation is 50 to greater than 125 centimeters (20 to

greater than 50 inches). Slopes range from 0 to 20 percent.

LTA Components: This landtype association has two components:

Soils in mountain grasslands are Typic and Argic Cryoborolls. They are deep,

medium textured, rocky, and have moderate fertility and water holding

capacity. Rock outcrop makes up 15 percent of this component. Common

potential vegetation includes Idaho fescue and big sagebrush series. This

component makes up 50 percent of this LTA.

Soils in forest are Typic Cryochrepts. They are deep, moderately coarse to

medium textured, rocky, and have moderate fertility and water holding

capacity. Rock outcrop makes of five percent of this component. Common

potential vegetation includes the subalpine fir series. This component makes

up 50 percent of this LTA.

Compiled by: Henry Shovic, Gallatin National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 66
LTA63-M331Ah

MOUNTAIN SLOPES AND RIDGES: GNEISSES AND SCHISTS

Location: This LTA is located in the Beartooth Mountains of southwest Montana.

 Acreage by Section:

 63-M331Ah 20,784

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a dissected mountain

landscape setting, which is typically composed of mountain slopes. Parent

materials are residuum underlain by gneiss and schist bedrock.

Accessory Characteristics: The primary soils are shallow to deep, with

moderately fine to coarse textures. The vegetation is a mosaic of coniferous

forest and mountain grassland. Mean annual precipitation ranges from 55 to 114

cms. (22 to 45 inches). The elevation range is 1981 to 2743 meters (6500 to

9000 feet). The dominant slopes have gradients of 30 to 60 percent. This unit

is slightly dissected by streams, with the dominant stream pattern being

dendritic. 

LTA Components: This landtype association consists of mountain slopes.

Mountain slopes are formed in residual gneiss and schist material. Slope

gradients range from 30 to 60 percent. Soils on these landforms are shallow to

deep, weakly developed, moderately fine to coarse textured. These soils are

classified as Typic Cryorthents, Typic Cryochrepts, and Typic Cryoboralfs.

Rock outcrop occurs on about 10 percent of this landscape component. The

dominant potential natural vegetation is Douglas-fir and subalpine fir. This

component represents 100 percent of this unit.

Compiled by: John R. Lane, Custer National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 67
LTA63-M331A

LTA63-M332E

MOUNTAIN SLOPES AND RIDGES: GNEISSES AND SCHISTS

Location: This LTA is located in the Tendoys, Gravellys, Tobacco Roots and

Madison Ranges in southwest Montana. Major drainages are the Red Rock,

Beaverhead, Ruby and Madison Rivers in the Jefferson Basin and Madison Basins.

 Acreage by Section:

 63-M331A 158,933 (Section except M331Ah)

 63-M332E 110,855

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in an unglaciated, mountain

slope landscape setting, below the elevational zone of strong and moderate

frost shattering. This unit is typically composed of dissected slopes with

ridges and narrow, mostly ephemeral, bottoms. Parent materials are colluvium

and residuum derived from Pre-Belt crystalline metamorphic rocks consisting of

hornblende gneiss, quartzite, meta-diabase, sillimanite schist, quartz-feldspar

gneiss, metamorphosed granite, and migmatite, including the Dillon

Granite-Gneiss in the Tendoy Mountains.

Accessory Characteristics: The primary soils are moderately deep, well

drained, dark colored, channery loams and fine sandy loams. The vegetation is

a mosaic of coniferous forest and mountain grassland. Mean annual precipitation

ranges from 36 to 102 centimeters (14 to 40 inches). The elevation range of

this LTA is 2042 to 2652 meters (6700 to 8700 feet). The dominant slopes have

gradients of 25 to 50 percent.

This LTA is moderately to highly dissected by streams, with the dominant stream

pattern being dendritic. Wetlands, lakes, and ponds are a minor component of

this LTA. 

LTA Components: This landtype association consists of slopes with rounded

ridges and narrow, steep, mostly ephemeral valley bottoms.

Mountain slopes and ridges are formed in colluvium and residuum. Slope

gradients range from 25 to 50 percent. Soils on these landforms are moderately

deep, weakly to moderately developed, channery loams and fine sandy loams.

These soils are classified as Typic Cryochrepts and Typic Cryoborolls. Rock

outcrop occurs on about 5 percent of this landscape component. The dominant

potential natural vegetation is big sagebrush, Douglas-fir, and subalpine fir

series. This landscape component represents about 98 percent of this LTA. 

Compiled by: Dan Svoboda, Beaverhead/Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 68
LTA64-M331A

LTA64-M332E

LTA64-M332D

MOUNTAIN SLOPES AND RIDGES: VOLCANICS

Location: This LTA is located in the Boulder, Elkhorn, Fleecer, Anaconda,

Pintlar, Beaverhead, Madison, Pioneer, Lima Peaks, Gravelly, Tendoy, and

Gallatin Mountains on the Beaverhead-Deerlodge, Helena, and Gallatin National

Forests. These occur in southwest Montana in the upper Missouri River Basin

and the upper Little Blackfoot drainage.

 Acreage by Section:

 64-M331A 21,460

 64-M332E 215,232

 64-M332D 197,349

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of stream dissected mountain slopes and

mountain ridges. Parent materials are residuum underlain by Tertiary and

Cretaceous volcanic bedrock, including andesite, dacite, rhyolite, welded and

non-welded rhyolite and felsic tuffs, and locally basalt and minor metagrabbro

dikes.

Accessory Characteristics: The primary soils are shallow, moderately deep and

deep loamy soils often with high cobble contents. The vegetation is a mosaic

of coniferous forest and shrubland/grassland, coniferous forest or shrubland

/grassland. Mean annual precipitation ranges from 38 to 75 centimeters (15 to 30

inches). The elevation range of this LTA is 1525 to 2378 meters (5000 to 7800

feet). The dominant slopes have gradients of 5 to 60 percent.

The mountain slopes component of this LTA is moderately dissected by streams

with the dominant stream patterns being parallel or dendritic. The mountain

ridges are generally undissected. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of stream dissected

mountain slopes, and mountain ridges.

Stream dissected mountain slopes are formed in colluvium and residuum over a

variety of volcanic bedrock. Some high elevation areas are influenced by

volcanic ash loess deposits. Slope gradients range from 25 to 60 percent.

Soils on these landforms are shallow, moderately deep and deep to bedrock.

They are moderately and weakly developed with cobbly and very cobbly loam

surface textures. The subsurface layers are very cobbly and extremely cobbly

loams. These soils are classified as Typic and Lithic Cryochrepts and

Cryoborolls, and Typic and Mollic Cryoboralfs. Rock outcrop occurs on about 10

percent of this landscape component. The dominant potential natural vegetation

is Douglas-fir and subalpine fir series. This component represents 50 percent

of this LTA.

Mountain ridges are formed in residuum and colluvium over a variety of volcanic

bedrock. Some high elevation areas are influenced by volcanic ash loess

deposits. Included in this component is rolling uplands found in the eastern

portion of the Elkhorns. Slope gradients range from 10 to 40 percent. Soils

on these landforms are mostly moderately deep and shallow to bedrock. They are

moderately and weakly developed with cobbly, stony and very cobbly loam or loam

surface textures. The subsurface layers are very cobbly, very stony, extremely

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 69
cobbly and extremely stony loams and clay loams. These soils are mostly

classified as Typic and Lithic Cryochrepts on forested sites and Argic and

Lithic Cryoborolls on grassland/shrublands. Rock outcrop occurs on about 10

percent of this landscape component. The dominant potential natural vegetation

is rough fescue, big sagebrush, Douglas-fir, and subalpine fir series. This

component represents 50 percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest; Larry Laing,

Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 70
LTA68-M331Ah

MOUNTAIN SLOPES AND RIDGES: SANDSTONES AND SHALES

Location: This LTA is located in the Beartooth Mountains of southwest Montana.

 Acreage by Subsection:

 68-M331Ah 3,211

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a dissected mountain

landscape setting, which is typically composed of mountain slopes. Parent

materials are residuum underlain by sandstone and shale bedrock.

Accessory Characteristics: The primary soils are shallow to moderately deep,

with channery moderately fine to coarse textures. The vegetation is a mosaic

of coniferous forest and mountain grassland. Mean annual precipitation ranges

from 51 to 69 cms. (20 to 27 inches). The elevation range is 1525 to 2195

meters (5000 to 7200 feet). The dominant slopes have gradients of 30 to 60

percent. This unit is slightly dissected by streams, with thedominant stream

pattern being dendritic. 

LTA Components: This landtype association consists of mountain slopes.

Mountain slopes are formed in residual sandstone and shale material. Slope

gradients range from 10 to 50 percent. Soils on these landforms are shallow to

moderately deep, moderately developed, channery moderately fine to coarse

textured. These soils are classified as Typic Argiborolls, Lithic

Haploborolls, and Typic Cryoboralfs. Rock outcrop occurs on about 20 percent

of this landscape component. The dominant potential natural vegetation is

subalpine fir, Douglas-fir, Idaho fescue and bluebunch wheatgrass. This

component represents 100 percent of this unit.

Compiled by: John R. Lane, Custer National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 71
LTA68-M331Aa

LTA68-M331Ap

LTA68-M332Dp

MOUNTAIN SLOPES AND RIDGES: SANDSTONES AND SHALES

Location: This unit is located in the Bridger, Gallatin, and Madison Mountain

Ranges in southwestern Montana.

 

 Acreage by Section:

 68-M331Aa 20,334

 68-M331Ap 79,259

 68-M332Dp 81,951

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit consists of a complex of

mountain slopes and ridges, with overall shapes controlled by underlying

bedrock structure. Soil parent material is colluvium and residuum derived from

thinly to thickly interbedded sandstone and shale with some limestone.

Accessory Characteristics: Vegetation is dense lower subalpine forest or

mountain grassland. Elevation ranges from 1981 to 2377 meters (6500 to 7800

feet). Mean annual precipitation is 75 to 100 centimeters (30 to 40 inches).

Slope ranges from 0 to 40 percent.

LTA Components: This landtype association has four components:

Soils in mountain grasslands are Typic Cryoborolls and Argic Cryoborolls. They

are deep, medium to moderately fine textured, rocky in some areas, and have

moderate to high fertility and water holding capacity. Rock outcrop makes up 5

percent of this component. Common potential vegetation includes Idah o fescue 

and big sagebrush series. This component makes up 20 percent of this LTA.

Where rock types are thinly interbedded sandstone and shale and vegetation is

densely or sparsely forested, soils are Typic and Mollic Cryoboralfs and Argic

Cryoborolls. They are deep, medium textured, rocky, and have moderate

fertility and water holding capacity. Rock outcrop makes of 5 to 20 percent of

this component. Common potential vegetation includes Douglas-fir, subalpine

fir, Idaho fescue and big sagebrush series. This component makes up 40 percent

of this LTA.

Where rock types are thickly interbedded sandstone and shale, and vegetation is

densely or sparsely forested, soils are Typic and Mollic Cryoboralfs, Argic

Cryoborolls, and Typic Argiborolls. They are deep, medium to moderately fine

textured, non-rocky, and have high fertility and water holding capacity. Rock

outcrop makes of 5 to 20 percent of this component. Common potential

vegetation includes subalpine fir, subalpine fir-whitebark pine, Douglas-fir,

Idaho fescue and big sagebrush series. This component makes up 20 percent of

this LTA.

Where rock types are limestone, sandstone, and shale, soils are Typic

Ustochrepts, Typic Calciborolls, Cryoboralfs and Cryochrepts. These soils are

deep to moderately shallow, moderately coarse to moderately fine textured,

rocky, and have low to moderate fertility and water holding capacity. Rock

outcrop makes up 15 to 25 percent of this component. Common potential

vegetation includes subalpine fir and Douglas-fir series. This component makes

up 20 percent of this LTA.

Compiled by: Henry Shovic, Gallatin National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 72
LTA68-M331A

LTA68-M332E

MOUNTAIN SLOPES AND RIDGES: SANDSTONES AND SHALES

Location: This LTA is located in the Lima Peaks (portion of Beaverhead Range),

Tendoy, Pioneers, Tobacco Roots, Gravellys, and Madison Range in southwest

Montana in the Jefferson and Madison Basins.

 Acreage by Subsection:

 68-M331A 49,804 (Section except M331Ah,M331Aa,M331Ap)

 68-M332E 262,471

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in an unglaciated, mountain

slope landscape setting below the elevational zone of strong and moderate frost

churning. This unit is typically composed of dissected slopes with ridges and

narrow, mostly ephemeral, bottoms. Parent materials are Tertiary to Cambrian

sediments undifferentiated, consisting of shale, siltstone, sandstone,

limestone, and calcareous clays. Minor gypsum, chert, and volcanic rock

occurs.

Accessory Characteristics: The primary soils are moderately deep, loams, clay

loams and silty clays. The vegetation is a mosaic of mountain grasslands and

coniferous forests. Mean annual precipitation ranges from 41 to 91 centimeters

(16 to 36 inches). The elevation range of this LTA is 2042 to 2682 meters (6700

to 8800 feet). The dominant slopes have gradients of 15 to 50 percent. This

LTA is moderately to highly dissected by streams, with the dominant stream

pattern being dendritic, but deranged in secondary mass wasting areas.

Wetlands, lakes, and ponds are a minor component of this LTA. 

LTA Components: This landtype association consists of slopes with rounded

ridges and narrow, steep, mostly ephemeral valley bottoms.

Mountain slopes and ridges are formed in colluvium-alluvium and residuum of

shale and sandstone parent materials. Slope gradients range from 15 to 50

percent. Soils on these landforms are moderately deep, moderately to highly

developed, dark colored, clay loams, silty clays, and sandy loams and loams.

These soils are classified as Argic Pachic Cryoborolls, Typic Cryoborolls, and

Mollic and Typic Cryoboralfs. Rock outcrop occurs on less than 5 percent of

this landscape component. The dominant potential natural vegetation is big

sagebrush, Idaho fescue and Douglas-fir series. This component represents

about 95 percent of this LTA. 

Compiled by: Dan Svoboda, Beaverhead/Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 73
LTA69-M331A

LTA69-M332E

PEDIMENTS: MIXED GEOLOGY

Location: This LTA is located the Lima Peaks (Beaverhead Mountains), Tendoys,

Gravellys, and southern Madison Range in southwest Montana in the Jefferson and

Madison Basins.

 Acreage by Section:

 69-M331A 412

 69-M332E 2,408

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in an unglaciated, mountain

slope landscape setting below the elevational zone of strong and moderate frost

churning. This unit is typically comprised of relatively undissected sloping

and gently sloping straight to slightly concave slopes, often with a thin

veneer of colluvium. Parent materials are mixed sedimentary, predominantly

Cretaceous sediments consisting of shale, siltstone, sandstone, and subordinate

conglomerate, limestone, and carbonaceous material, and including minor

volcanic rock. The colluvial veneer is apparently Quaternary aged deposits.

Accessory Characteristics: The primary soils are shallow, well drained,

gravelly loams. The vegetation is a mosaic of mountain grassland and

coniferous forest. Mean annual precipitation ranges from 36 to 61 centimeters

(14 to 24 inches). The elevation range of this LTA is 2042 to 2347 meters

(6700 to 7700 feet). The dominant slopes have gradients of less than 20

percent. This LTA is weakly dissected by streams, with the dominant stream

pattern being parallel. Wetlands, lakes, and ponds are absent in this LTA. 

LTA Components: This landtype association consists of relatively long, smooth,

straight to slightly concave slopes.

Pediment slopes are formed in residuum of shale, sandstone, and limestone

parent material. Slope gradients range from less than 10 to 20 percent.

Soils on these landforms are shallow, moderately developed, gravel ly loams.

These soils are classified as Lithic Calciborolls and Typic Calciborolls. Rock

outcrop typically does not occur on this landscape component. The dominant

potential natural vegetation is the big sagebrush series. This component

represents 100 percent of this LTA.

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 74
LTA72-M331A

LTA72-M332Dc

LTA72-M332Cp

LTA72-M332E

FROST SHATTERED MOUNTAIN RIDGE TOPS:

WEAKLY WEATHERED GRANITICS

Location: This unit is located in the Gallatin, Madison, Absaroka-Beartooth

mountain ranges in southwestern Montana. Included is the Crazy Mountains,

Bridger Mountains, Anaconda Mountains, and Continental Divide Uplands.

 Acreage by Section:

 72-M331A 25,079

 72-M332Dc 1,571

 72-M332Dp 106

 72-M332E 838

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit consists of rounded ridgetops

with weak stream dissection. Soil parent material is frost shattered glacial

till and colluvium derived from hard crystalline rocks such as granite.

Accessory Characteristics: Vegetation is alpine turf or sparse to dense upper

subalpine and lower subalpine forest. Elevation ranges from 1981 to 2987

meters (6500 to 9800 feet). Mean annual precipitation is greater than 125

centimeters (50 inches). Slopes range from 0 to 20 percent.

LTA Components: This landtype association has two components:

Soils on rounded ridgetops in forest are Typic and Dystric Cryochrepts. They

are deep, moderately coarse textured, rocky, and have low fertility and water

holding capacity. Rock outcrop makes up five percent of this component. The

dominant potential natural vegetation is the subalpine fir, and subalpine

fir-whitebark pine series. This component makes up 70 percent of this LTA.

Soils on rounded ridgetops with alpine turf are Dystric Cryochrepts. They are

moderately deep, coarse textured, rocky, and have low fertility and water

holding capacity. Rock outcrop makes up 20 percent of this component. A

common potential natural vegetation series is Idaho fescue. This component

makes up 30 percent of this LTA.

Compiled by: Henry Shovic, Gallatin National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 75
LTA73-M331A

FROST SHATTERED MOUNTAIN RIDGE TOPS: VOLCANICS

Location: This unit is located in the Gallatin and Absaroka-Beartooth mountain

ranges in southwestern Montana.

 Acreage by Section:

 73-M331A 16,886

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit consists of rounded ridgetops

with weak stream dissection. Soil parent material is frost shattered glacial

till and colluvium derived from andesitic volcanic rocks.

Accessory Characteristics: Vegetation is alpine turf or sparse to dense upper

subalpine and lower subalpine forest interspersed with mountain meadows.

Elevation ranges from 2195 to 2987 meters (7200 to 9800 feet). Mean annual

precipitation is 75 to greater than 125 centimeters (30 to greater than 50

inches). Slope ranges from 0 to 20 percent.

LTA components: This landtype association has two components:

Soils on rounded ridgetops in forest are Mollic Cryoboralfs. They are deep,

medium textured, rocky, and have moderate fertility and water holding

capacity. Rock outcrop makes up five percent of this component. Common

potential natural vegetation is the Idaho fescue, subalpine fir, and subalpine

fir-whitebark pine series. This component makes up 70 percent of this LTA.

Soils on rounded ridgetops with alpine turf are Argic Cryoborolls and Typic

Cryochrepts. They are deep to shallow, medium textured, rocky and have low to

moderate fertility and water holding capacity. Rock outcrop makes up five

percent of this component. A common potential natural vegetation is the Idaho

fescue series. This component makes up 30 percent of this LTA.

Compiled by: Henry Shovic, Gallatin National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 76
LTA74-M331A

LTA74-M332D

LTA74-M332E

FROST SHATTERED MOUNTAIN RIDGE TOPS:

SANDSTONES AND SHALES

Location: This LTA is located in the Pioneers, Fleecers, Beaverhead Mountains,

(south), Tendoys, Tobacco Roots, Gravellys, and Madison Ranges. These occur in

southwest Montana on the Beaverhead-Deerlodge National Forest in the Jefferson

and Madison Basins.

 Acreage by Section:

 

 74-M331A 10,729

 74-M332D 859

 74-M332E 70,884

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a relatively high

elevation, gently to moderately sloping mountain landscape setting, at or above

the zone of moderate and strong frost shattered. The unit is typically

composed of frost shattered ridges and slopes, ranging from patterned ground to

soil heaving. Parent materials are colluvium and residuum from Tertiary

sediments consisting of shale, siltstone, sandstone, limestone, and calcareous

clays. Minor gypsum, chert, and volcanic rocks occur.

Accessory Characteristics: The primary soils are very shallow to moderately

deep silt loams, loams and clay loams. The vegetation is a mosaic of alpine

turf, alpine and subalpine coniferous forest, and mountain grasslands. Mean

annual precipitation ranges from 41 to 127 centimeters (16 to 50 inches). The

elevation range of this LTA is 2195 to 3048 meters (7200 to 10000 feet). The

dominant slopes have gradients of 10 to 40 percent. This LTA is slightly

dissected by streams, with the dominant stream pattern being dendritic.

Wetlands, lakes, and ponds are a minor component of this LTA.

LTA Components: This landtype association consists of frost shattered ridges

and slopes. 

Frost shattered ridges and slopes are formed in colluvium and residuum derived

from sandstones and shales. Slope gradients range from 10 to 50 percent.

Soils on these landforms are very shallow to moderately deep, weakly to

moderately well developed, silt loams, loams, and clay loams. The surface

soils can be highly organic above 9000 feet (2743 meters). These soils are

classified as Lithic Cryoborolls and Typic Cryoborolls, Typic Cryochrepts, and

Mollic Cryoboralfs. Rock outcrop occurs on about 5 percent of this landscape

component. The dominant potential natural vegetation is Idaho fescue,

subalpine fir, Douglas-fir, and subalpine fir-whitebark pine series with sedges

and rushes. This component represents 95 percent of this LTA.

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 77
LTA77-M331Ah

FROST SHATTERED MOUNTAIN RIDGE TOPS: GNEISSES AND SCHISTS

Location: This LTA is located in the Beartooth Mountains of southwest Montana.

 Acreage by Subsection:

 77-M331Ah 44,401

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a high elevation

mountain landscape setting, typically composed of frost shattered ridge tops.

Parent materials are residuum underlain by weakly metamorphosed, gneiss and

schist bedrock with some loess (wind blown silt) on the surface.

Accessory Characteristics: The primary soils are shallow, with medium

textures. The vegetation is a mosaic of alpine turfs and scattered whitebark

pine stands. Mean annual precipitation ranges from 89 to 152 cms. (35 to 60

inches). The elevation range is 2743 to 3292 meters (9000 to 10800 feet . The )

dominant slopes have gradients of 0 to 20 percent.

LTA Components: This landtype association consists of frost shattered ridge

tops.

Frost shattered ridges tops are formed in residual gneiss and schist material.

Slope gradients range from 0 to 20 percent. Soils on these landforms are

shallow, weakly developed, medium textured. These soils are classified as

Lithic Cryochrepts. Rock outcrop occurs on about 20 percent of this landscape

component. The dominant potential natural vegetation is alpine turf consisting

of tufted hairgrass, fescues, bluegrass and sedges. This component

represents 100 percent of this unit.

Compiled by: John R. Lane, Custer National Forest and Henry Shovic, Gallatin

National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 78
LTA77-M331A

LTA77-M332E

FROST SHATTERED MOUNTAIN RIDGE TOPS: GNEISSES AND SCHISTS

Location: This LTA is located the Tobacco Root and Madison Ranges in southwest

Montana in the Jefferson and Madison Basins.

 Acreage by Section:

 77-M331A 18,510 (Section except M331Ah)

 77-M332E 18,667

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a relatively high

elevation gently to moderately sloping mountain landscape setting, at or above

the zone of moderate and strong frost shattering. The unit is typically

composed of frost shattered ridges and slopes, ranging from patterned ground to

soil heaving. Parent materials are colluvium and residuum from Pre-Belt

crystalline metamorphic rocks consisting of hornblende gneiss, quartzite,

meta-diabase, sillimanite schist, quartz-feldspar gneiss, metamorphosed

granite, and migmatite.

Accessory Characteristics: The primary soils are shallow to moderately deep,

channery loams and sandy loams. The vegetation is a mosaic of alpine turf,

talus, subalpine and montane coniferous forest, and mountain grasslands. Mean

annual precipitation ranges from 41 to 91 centimeters (16 to 36 inches). The

elevation range of this LTA is 2134 to 2743 meters (7000 to 9000 feet). The

dominant slopes have gradients of 20 to 40 percent. This LTA is weakly

dissected by streams, with the dominant stream pattern being dendritic.

Wetlands, lakes, and ponds are a minor component of this LTA. 

LTA Components: This landtype association consists of frost shattered ridges

and slopes. 

Frost shattered ridges and slopes are formed in colluvium and residuum derived

from gneiss/schist. Slope gradients range from 15 to 40 percent. Soils on

these landforms are moderately deep, well drained, weakly to moderately

developed, channery sandy loams. These soils are classified as Lithic and

Typic Cryoborolls, and Lithic and Typic Cryochrepts. Rock outcrop occurs on

about 10 percent of this landscape component. The dominant potential natural

vegetation is whitebark pine-subalpine fir, subalpine fir and Douglas-fir

series with several sedges. This component represents 98 percent of this LTA.

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 79
LTA90-M331Am

LTA90-M331Ap

LTA90-M332E

MASS WASTED SLOPES: MIXED GEOLOGY

Location: This LTA is located in the Madison, Tobacco Root, Fleecer, Pioneer,

Anaconda Pintlar, Beaverhead, Lima Peaks, and Tendoy Mountains of southwest

Montana in the Jefferson and Madison Basins.

 Acreage by Section:

 90-M331Am 11,231

 90-M331Ap 55,734

 90-M332E 25,903 (Section except M332Ea,M332Eb,M332En)

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a foothills to mountain

landscape setting which is typically composed of deep bedrock (hundreds of feet

thick) and surficial (tens of feet thick) mass failures, both translational and

rotational. Parent materials are landslide deposits, colluvium, and residuum

derived mostly from Cretaceous and Tertiary shales and sandstones.

Accessory Characteristics: The primary soils are deep, silty clay loams, silty

clays, and clays. The vegetation is a mosaic of subalpine coniferous forest,

montane coniferous forest, and subalpine and mountain grasslands. Mean annual

precipitation ranges from 36 to 102 centimeters (14 to 40 inches). The

elevation range of this LTA is 2012 to 2804 meters (6600 to 9200 feet). The

dominant slopes have gradients of 20 to 35 percent. This LTA is moderately

dissected by streams, with the dominant stream pattern being deranged to

dendritic. Wetlands and small ponds are a major component of this LTA. 

LTA Components: This landtype association consists of scarp slopes and

landslide deposits.

Scarp slopes are formed in colluvium, residuum, and sometimes old glacial

deposits. Slope gradients range from 20 to 70 percent. Soils on these

landforms are very shallow to shallow, weakly developed, channery and flaggy

sandy loams, loamy fine sands, clay loams, and silty clays, and clays. These

soils are classified as Typic Cryorthents and Typic Cryochrepts. Rock outcrop

occurs on about 15 percent of this landscape component. The dominant potential

natural vegetation is whitebark pine-subalpine fir and tufted hairgrass series

with numerous early successional forb communities and primary succession. This

component represents 10 percent of this LTA.

Landslide deposits and mountain slopes are formed in colluvium, residuum, old

landslide deposits, and sometimes old glacial deposits (Bull Lake). Slope

gradients range from 10 to 50 percent. Soils on these landforms are deep,

moderately well developed, silty clay loams, silty clays and clays. These

soils are classified as Aquic, Mollic, and Typic Cryoboralfs, Typic

Argiborolls, and Argic Pachic Cryoborolls. Rock outcrop occurs on about 5

percent of this landscape component. The dominant potential vegetation is

tufted hairgrass, whitebark pine, spruce, subalpine fir, aspen and Idaho fescue

series. This component represents 85 percent of this landscape component.

Compiled by: Dan Svoboda, Beaverhead/Deer Lodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 80
LTA90-M331A

MASS WASTED SLOPES: MIXED GEOLOGY

Location: This map unit occurs throughout the Gallatin National Forest, in

southwestern Montana and in the Beartooth Mountains on the Custer National

Forest.

 Acreage by Section:

 90-M331A 46,492 (rest of Section except M331Am,M331Ap)

LTA Setting and General Characteristics:

Differentiating Characteristics: This map unit consists of large earthflows.

Parent material is landslide deposits derived from interbedded sandstone,

limestone, and shale; or andesitic volcanic rocks.

Accessory Characteristics: Vegetation is dense upper or lower subalpine

forest, dense to sparse Douglas-fir forest, mountain grasslands, and meadows.

Elevation ranges from 1676 to 2316 meters (5500 to 7600 feet). Mean annual

precipitation is 53 to 74 cms. (21 to 29 inches). Slope ranges from 0 to 60

percent.

LTA Components: This landtype association has two components:

Where forest is sparse to dense Douglas-fir forest and grasslands, soils are

Argic Cryoborolls, Mollic Cryoboralfs, and Argic Pachic Cryoborolls. These

soils are moderately fine to fine textured, rocky and non-rocky, and have

moderate to high fertility and water holding capacity. Some areas have Typic

Cryorthents, Lithic Cryorthents, or Vertic Haploborolls. Common potential

natural vegetation includes Idaho fescue, big sagebrush and Douglas-fir

series. This component makes up 20 percent of this LTA.

Where forest is dense upper or lower subalpine forest and meadows, soils are

Cryoboralfs and some Cryoborolls. These soils are moderately fine to fine

textured, rocky and non-rocky, and have moderate to high fertility and water

holding capacity. Common potential natural vegetation includes subalpine fir,

subalpine fir-whitebark pine, and Idaho fescue series. This component makes up

80 percent of this LTA.

Compiled by: Henry Shovic, Gallatin National Forest and John R. Lane, Custer

National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 81
CHAPTER 5

LTA Descriptions

Section M332A Idaho Batholith

This Section occurs mostly in central Idaho extending a short distance into

west central Montana. It generally coincides with the Idaho Batholith Uplands

geomorphic area previously described. Thirty two LTAs were mapped in this

Section. See Appendix F for a complete list of LTAs and their acreages.

The map unit descriptions are preceded by the following illustrations:

 Figure 15: Map showing location of M332A within the Northern Region

 Figure 16: M332A landscape photograph of Bitterroot Mountain Range,

 Bitterroot National Forest

 Figure 17: Map showing distribution of LTAS within M332A

 Figure 18: Bar chart showing abundance of major landform groups within M332A

 Figure 19: Bar chart showing abundance of major geologic material groups 

 within M332A

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 82
LTA10-M332A

VALLEYS: RECENT, COARSE ALLUVIUM

Location: This unit is located in valley bottoms along larger streams in north

central Idaho, in the Salmon and Clearwater River Basins.

 Acreage by Section

 10-M332A 9,587

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs on valley bottom

landscape settings and consists of floodplains and terraces. Parent materials

are recent alluvial deposits derived from granite, schist, quartzite, or

gneiss.

Accessory Characteristics: The primary soils are very deep loams or silt loams

over gravelly or cobbly sand or loamy sand substrata. The vegetation is a

mosaic of coniferous forest, wet meadows, and hardwood forest or shrubland.

Mean annual precipitation ranges from 50 to 100 centimeters (20 to 40 inches).

The elevation range is 550 to 1600 meters (1800 to 5300 feet). The dominant

slopes gradients are 0 to 10 percent. This unit is moderately dissected by

streams; the dominant stream pattern is dendritic. Wetlands are a major

component of this unit.

LTA Components: This landtype association consists of stream terraces and

floodplains.

Stream terraces are formed in mixed coarse textured alluvium. Slope gradients

range from 1 to 10 percent. Soils on this landform are very deep and

moderately well drained to somewhat poorly drained. These soils are weakly to

moderately developed loams and silt loams over sand and gravel to cobble-sized

rocks. The dominant soils are classified as Entic or Aquic Cryumbrepts, frigid

Haplumbrepts, and Andic Cryochrepts. Rock outcrops do not occur in this

landscape component. The dominant potential natural vegetation is mixed

hardwoods at low elevations, and subalpine fir at higher elevations. This

component represents about 50 percent of this unit.

Floodplains are formed in mixed volcanic ash influenced loess and gravelly or

cobbly, sandy recent alluvium. Slope gradients range from 1 to 3 percent.

Soils on this landform are very deep and poorly drained. These soils are

weakly developed and consist mostly of cobbles, gravels and sands. The

dominant soils are classified as Typic Fluvaquents and Humic Cryaquents. Rock

outcrop does not occur on this landscape component. Areas of cobbly to

gravelly riverwash make up about 10 percent of this unit. The dominant

vegetation is a complex of sedge meadow, willow, or subalpine fir. This

component represents about 40 percent of this unit.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 83
LTA12-M332A

VALLEYS: OUTWASH AND OTHER OLDER COARSE ALLUVIUM

Location: This unit is located in major river valleys in north central Idaho

in the Salmon and Clearwater River Basins.

 Acreage by Section

 12-M332A 10,308

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs on valley bottoms of

canyon breaklands and is dominated by old high terraces. These occur with low

flood plains and alluvial fans. Parent materials are mixed alluvium underlain

by undifferentiated lithology.

Accessory Characteristics: The primary soils are very deep sands, sandy loams,

and loams over cobbles and gravels. The vegetation is a mosaic of grassland

and coniferous forest with some unvegetated cobble and sand bars. Mean annual

precipitation ranges from 51 to 64 centimeters (15 to 25 inches). The

elevation range is 450 to 750 meters (1200 to 2500 feet). The dominant slopes

have gradients of 1 to 30 percent. This unit is adjacent to large rivers and

may be dissected by smaller streams. In low floodplains and fans, wetlands and

cobble and sand bars are numerous. 

LTA Components: This landtype association consists of floodplains, older

terraces, and alluvial fans.

Old terraces are formed in old alluvium and loess. Slope gradients range from 1

percent on terrace floors to near vertical on truncated terrace faces. Soils on

these landforms ae very deep, moderately developed sandy loams and loams with

loamy substrata. These soils are classified as Calcic Haploxerolls. Rock

outcrop is uncommon. The dominant potential natural vegetation is bluebunch

wheatgrass or ponderosa pine. This component represents 65 percent of this

unit.

Floodplains are formed in recent alluvium of mixed lithology. Slope gradients

range from 1 to 3 percent. Soils on these landforms are deep to very deep,

poorly developed stratified sands, gravels, cobbles and some fine material.

These soils are classified as cobbly Typic Xerofluvents. Rock outcrop is

uncommon. The dominant potential natural vegetation is bluebunch wheatgrass or

ponderosa pine. This component represents 20 percent of this unit.

Alluvial fans are formed in coarse Recent alluvium at the mouth of tributary

streams. Slope gradients range from 5 to 30 percent. Soils on these landforms

are very deep, poorly developed, poorly stratified sands, gravels, cobbles and

boulders. These soils are classified as cobbly Typic Xerofluvents and

Udifluvents. Rock outcrop is uncommon. Plant communities are often dominated

by willow, cottonwood, and white alder near streams and Douglas--fir or

ponderosa pine series on drier positions. This component represents 15 percent

of this unit.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 84
LTA14-M332A

VALLEYS: RECENT FINE ALLUVIUM

Location: This unit is located in the Bitterroot Mountains of Idaho west of

the Montana border in the upper Lochsa River Basin.

 Acreage by Section

 14-M332A 8,101

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a valley bottom

landscape setting, which is typically composed of floodplains, alluvial

basins, and stream terraces. Parent materials are recent, fine, alluvial

deposits primarily underlain by granitics of the Idaho Batholith

Accessory Characteristics: The primary soils are moderately deep to deep with

moderately fine to fine textures. The vegetation is a mosaic of moist to wet

coniferous forest, riparian shrub communities, and mesic to wet meadows. Mean

annual precipitation ranges from 89 to 114 cms. (35 to 45 inches). The

elevation range is 914 to 1372 meters (3500 to 4500 feet). The dominant slopes

have gradients of 0 to 10 percent. This unit is moderately dissected by

streams, with the dominant stream pattern being dendritic. Wetlands and ponds

are a major component of this unit.

LTA Components: This landtype association consists of flood plains, alluvial

basins, and stream terraces.

Flood plains and alluvial basins are formed in moderately fine-textured recent

alluvium. Slope gradients range from 0 to 3 percent. Soils on these landforms

are deep, weakly to moderately developed, and consist mostly of silt loam and

silty clay loam textures. These soils are classified as Typic Cryaquepts, Aquic

Cryochrepts, and Cumulic Cryaquolls. Rock outcrop occurs on less than 1

percent of this landscape component. The dominant potential natural vegetation

are mesic to wet grass/sedge associations, willow/alder associations, and

western redcedar/subalpine fir series. This component represents 80 percent of

this unit.

Stream terraces are formed in mixed alluvium. Slope gradients range from 2 to

10 percent. Soils on these landforms are deep, weakly developed, and consist

mostly of medium to moderately fine textures. These soils are classified as

Typic Eutrochrepts and Dystric Cryochrepts. Rock outcrop occurs on less than 1

percent of this landscape component. The dominant potential natural vegetation

series are western redcedar, grand fir, and subalpine fir. This component

represents 20 percent of this unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 85
LTA20-M332A

BREAKS: METASEDIMENTARY (BELT)

Location: This unit is located in the Bitterroot Mountains of Idaho west of

the Montana border in the upper Lochsa River Basin.

 Acreage by Section

 20-M332A 8,071

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a very steep, deeply

eroded landscape setting which is typically composed of stream or structural

breaks. Parent materials are mixed Mazama volcanic ash underlain by highly

metamorphosed metasediments of the Belt Series.

Accessory Characteristics: The primary soils are shallow to deep with textures

ranging from silt loams to very gravelly loams. The vegetation is primarily

coniferous forest with numerous rock outcrops. Mean annual precipitation

ranges from 89 to 114 cms. (35 to 45 inches). The elevation range is 1067 to

1676 meters (3500 to 5500 feet). The dominant slopes have gradients of 60 to

100 percent. This unit is moderately to highly dissected by streams, with the

dominant stream pattern being parallel. Wetlands are generally not present in

this unit.

LTA Components: This landtype association consists primarily of stream breaks,

some of which formed along structural breaks.

Stream breaks are formed in colluvial materials from highly weathered

metasedimentary Belt Series rocks with a mixed surface layer of Mazama volcanic

ash of varying thickness. Slope gradients range from 60 to 100 percent. Soils

on these landforms are shallow to moderately deep, weakly developed with silt

loam to loam surface textures and very gravelly to cobbly subsurface textures.

These soils are classified as Typic Dystrochrepts, Andic Dystrochrepts, and

Vitrandic Dystrochrepts. Rock outcrop occurs on 10 to 30 percent of this

landscape component. The dominant potential natural vegetation series are

western redcedar and grand fir. This component represents 100 percent of this

unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 86
LTA21-M332A

BREAKS: HIGHLY WEATHERED GRANITICS

Location: This unit is located in the Clearwater and Bitterroot Mountains of

north-central Idaho in the Lochsa, Selway, and Salmon River Basins.

 Acreage by Section

 21-M332A 209,877

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a very steep, deeply

eroded landscape setting which is typically composed of stream or structural

breaks. Parent materials are a mixed Mazama volcanic ashcap of variable

thickness underlain by highly weathered granitics of the Idaho Batholith.

Accessory Characteristics: The primary soils are shallow to and deep with

textures ranging from silt loams to extremely gravelly sandy loams and loamy

sands. The vegetation is primarily coniferous forest with numerous rock

outcrops. Mean annual precipitation ranges from 51 to 152 cms. (20 to 60

inches). The elevation range is 762 to 2286 meters (2500 to 7500 feet). The

dominant slopes have gradients of 60 to 100 percent. This unit is moderately

to highly dissected by streams, with the dominant stream pattern being

parallel. Wetlands are a minor component on valley floors.

LTA Components: This landtype association consists primarily of stream breaks,

some of which formed along structural breaks.

Stream breaks are formed in colluvial materials from highly weathered granitic

rocks of the Idaho Batholith with a mixed surface layer of Mazama volcanic ash

of varying thickness. Slope gradients range from 60 to 100 percent. Soils on

these landforms are shallow to deep, weakly developed with silt loam to

gravelly sandy loam surface textures and very gravelly to extremely gravelly or

cobbly to extremely cobbly loamy sand to sandy clay loam subsurface textures.

These soils are classified as Typic Dystrochrepts, Vitrandic Dystrochrepts,

Typic Ustochrepts, and Dystric Cryochrepts. Rock outcrop occurs on 20 to 40

percent of this landscape component. The dominant potential natural vegetation

series are western redcedar, grand fir, Douglas-fir, and subalpine fir. This

component represents 100 percent of this unit.

Compiled by: Jim Mital, Clearwater National Forest, and Ken McBride,

Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 87
LTA22-M332A

BREAKS: WEAKLY WEATHERED GRANITICS

Location: This unit is located in the Clearwater and Bitterroot Mountains and

of central Idaho in the Clearwater and Salmon River Basins.

 Acreage by Section

 22-M332A 283,624

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs on a very steep, deeply

eroded or faulted landscape setting which is typically composed of structural

and stream breaks. Parent material is colluvium and residuum derived from

weakly weathered granitic and gneissic bedrock.

Accessory Characteristics: The primary soils are shallow to very deep with

very gravelly, very cobbly or extremely gravelly coarse to medium textures.

The vegetation is a mosaic of grassland, shrublands, and dry coniferous

forest. Mean annual precipitation ranges from 51 to 76 cms. (15 to 45 inches).

The elevation range is 853 to 2134 meters (2500 to 7500 feet). The dominant

slopes have gradients greater than 60 percent. This unit is moderately to

highly dissected by streams, with the dominant stream pattern being parallel.

Rock outcrop, talus, and scree combined, are major components of this map

unit. Wetlands are a minor component of this unit. Wide valley bottoms occur

in this unit, but are generally considered only map unit inclusions.

LTA Components: This landtype association consists of structural and stream

breaks.

These landforms are formed in colluvium and residuum. Slope gradients range

from 60 to 90 percent. Soils on these landforms are shallow to very deep and

well drained. These soils are weakly developed and consist of loam to very

gravelly sandy loam surfaces overlying gravelly to extremely gravelly sandy

loam or loamy sand substrata. The dominant soils at low to mid- elevations are

classified as Typic and Lithic Ustochrepts, Ultic Haploxerolls, and Typic

Udivitrands. At high elevations, Dystric Cryochrepts occur. Rock outcrop,

talus and scree occupy up to about 25 percent of this map unit. The dominant

natural potential vegetation at low elevations includes Idaho fescue, bluebunch

wheatgrass or shrublands (generally found on shallow soils, rock outcrop,

talus, or scree) including curl-leaf mountain mahogany. The dry coniferous

forest plant associations are ponderosa pine and Douglas-fir. In moist

settings grand fir occurs. In the northwest part of this section, western

redcedar occurs and at high elevations, subalpine fir occurs.

Compiled by: Bob Spokas, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 88
LTA23-M332A

BREAKS: SCHISTS AND GNEISSES

Location: This unit is located in the Clearwater Mountains of north-central

Idaho in the lower Selway River Basin.

 Acreage by Section

 23-M332A 129,750

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a very steep, deeply

eroded landscape setting which is typically composed of stream or structural

breaks. Parent materials are moderately weathered gneisses and schists with a

variable thickness of Mazama volcanic ash.

Accessory Characteristics: The primary soils are shallow to moderately deep

with textures ranging from silt loams to very gravelly loams. The vegetation

is a mosaic of coniferous forest with numerous rock outcrops and grassy

openings. Mean annual precipitation ranges from 64 to 89 cms. (25 to 35

inches. The elevation range is 366 to 1524 meters (1200 to 5000 feet). The

dominant slopes have gradients of 60 to 100 percent. This unit is moderately

dissected by streams, with the dominant stream pattern being parallel.

Wetlands are generally not present in this unit.

LTA Components: This landtype association consists primarily of stream breaks,

some of which formed along structural breaks.

Stream breaks are formed in colluvial materials from moderately weathered

gneisses and schists with a variable thickness of Mazama volcanic ash mixed in

the surface layer. Slope gradients range from 60 to 100 percent. Soils on

these landforms are shallow to moderately deep, weakly developed with silt loam

to loam surface textures and very gravelly to cobbly subsurface textures.

These soils are classified as Ultic Haploxerolls, Typic Dystrochrepts, and

Andic Dystrochrepts. Rock outcrop occurs on 10 to 30 percent of this landscape

component. The dominant potential natural vegetation series areDouglas-fir,

grand fir, and Idaho fescue. This component represents 100 percent of this

unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 89
LTA24-M332A

BREAKS: VOLCANICS

Location: This unit is located in the Clearwater River Basin of west-central

Idaho.

 Acreage by Section

 24-M332A 11,592

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a very steep, deeply

eroded landscape setting which is typically composed of stream breaklands.

Parent materials are weakly to moderately weathered Columbia flood basalts

overlain with a variable thickness of wind-blown loess.

Accessory Characteristics: The primary soils are shallow to moderately deep

with textures ranging from silt loams to very cobbly loams. The vegetation is

a mosaic of grasslands with some shrubland inclusions. Mean annual

precipitation ranges from 51 to 76 cms. (20 to 30 inches). The elevation range

is 458 to 914 meters (1500 to 3000 feet). The dominant slopes have gradients

of 60 to 80 percent. This unit is moderately dissected by streams, with the

dominant stream pattern being parallel. Wetlands are generally not present in

this unit.

LTA Components: This landtype association consists primarily of stream breaks.

Stream breaks are formed in colluvial materials from weakly to moderately

weathered Columbia flood basalts with a variable layer of loess mixed in the

surface layer. Slope gradients range from 60 to 80 percent. Soils on these

landforms are shallow to moderately deep, weakly developed with silt loam to

loam surface textures and very gravelly to cobbly subsurface textures. These

soils are classified as Typic Haploxerolls, Lithic Argixerolls, and Ultic

Argixerolls. Rock outcrop occurs on 20 to 40 percent of this landscape

component. The dominant potential natural vegetation series are Idaho fescue,

bluebunch wheatgrass, with ponderosa pine and Douglas-fir present in the

moister settings. This component represents 90 percent of this unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 90
LTA26-M332A

BREAKS: MODERATELY WEATHERED GNEISSES, QUARTZITES AND SCHISTS

Location: This unit is located along streams and rivers in north central and

central Idaho.

 Acreage by Section

 26-M332A 215,945

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is composed of dissected

stream breaks. Parent materials are moderately weathered gneiss, quartzite,

and schist associated with the Idaho Batholith.

Accessory Characteristics: The primary soils are moderately deep to deep sandy

loams and loams. The vegetation is a mosaic of grassland and coniferous

forest. Mean annual precipitation ranges from 46 to 114 centimeters (18 to 45

inches). The elevation range is 550 to 2000 meters (1800 to 6600 feet). The

dominant slopes have gradients of 50 to 80 percent. This unit is moderately

dissected by streams, with the dominant stream pattern being parallel. 

LTA Components: This landtype association consists of dissected breaks.

Breaks are formed in mixed volcanic ash influenced loess, residuum and

colluvium of felsic metamorphic lithology. Soils on these landforms are

moderately deep to very deep, moderately developed loams and sandy loams with

sandy or loamy substrata. These soils are classified as Ultic Haploxerolls,

Typic Dystrochrepts, and Dystric Cryochrepts. Rock outcrop is less than 25

percent of the unit. The dominant potential natural vegetation at low

elevations is bluebunch wheatgrass and Idaho fescue, at mid-elevations

Douglas-fir and grand fir, and at high elevations, subalpine fir.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 91
LTA29-M332A

BREAKS: QUARTZITES AND CALC-SILICATES

Location: This unit is located in the Bitterroot Mountains and occurs in the

Selway River Basin of central Idaho.

 Acreage by Section

 29-M332A 10,533

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs on a very steep, deeply

eroded or faulted landscape setting which is typically composed of structural

and stream breaks. Parent material is colluvium and residuum derived from

weakly weathered quartzite and calc-silicates of the Belt Supergroup.

Accessory Characteristics: The primary soils are shallow to deep with very

gravelly, very cobbly or extremely gravelly coarse to medium textures. The

vegetation is a mosaic of dry to moist coniferous forest. Mean annual

precipitation ranges from 63 to 102 centimeters (25 to 40 inches). The

elevation range is 914 to 2073 meters (3000 to 6800 feet). The dominant slopes

have gradients greater than 60 percent. This unit is moderately to highly

dissected by streams, with the dominant stream pattern being parallel. Rock

outcrop, talus, and scree combined, are major components of this map unit.

Wetlands are a minor component of this unit. Wide valley bottoms occur in this

unit, but are generally considered only map unit inclusions.

LTA Components: This landtype association consists of structural and stream

breaks.

These landforms are formed in colluvium and residuum. Slope gradients range

from 50 to 90 percent. Soils on these landforms are shallow to deep and well

drained. These soils are weakly developed, and consist of very cobbly loam

surfaces overlying very cobbly sandy loam substrata. The dominant soils are

classified as: Typic and Lithic Ustochrepts, Typic Eutroboralfs, Lithic

Argiborolls, and Dystric and Lithic Cryochrepts. Rock outcrop, talus and scree

occupy about 20 percent of this map unit. On warmer, drier sites the dominant

natural vegetation is Douglas-fir series. On cool, mesic sites it is subalpine

fir series. Stream and structural breaks represent about 85 percent of this

unit.

Compiled by: Bob Spokas, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 92
LTA39-M332A

STEEP GLACIATED MOUNTAIN SLOPES: GNEISSES, QUARTZITES AND SCHISTS

Location: This unit is located in high elevation glaciated areas of north

central and central Idaho in the Salmon River and Selway River basin.

 Acreage by Section

 39-M332A 42,652

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is composed of steep glacial

trough walls and cirques. Parent materials are poorly weathered gneiss,

quartzite, and schist associated with the Idaho Batholith.

Accessory Characteristics: The primary soils are shallow to deep gravelly

sandy loams and loams. The vegetation is coniferous forest with inclusions of

shrub or herbaceous dominated openings. Mean annual precipitation ranges from

76 to 119 centimeters (30 to 47 inches). The elevation range is 1250 to 2500

meters (4100 to 8200 feet). The dominant slopes have gradients of 50 percent

to near vertical. This unit is moderately dissected by streams, with the

dominant stream pattern being parallel. Wetlands and lakes are significant

inclusions in basins and toeslopes.

LTA Components: This landtype association consists of dissected trough walls

and cirque headwalls.

Dissected troughwalls are formed in mixed volcanic ash influenced loess, till,

residuum and colluvium of felsic metamorphic lithology. Slope gradients range

from 50 to 80 percent. Soils on these landforms are moderately deep to deep,

weakly developed gravelly loams and sandy loams with cobbly sand substrata.

These soils are classified as Dystric Cryochrepts. Rock outcrop is less than

25 percent of the unit. The dominant potential natural vegetation at mid

elevations is grand fir, and at high elevations - subalpine fir.

Cirque headwalls are formed in till, residuum, and colluvium of acid

metamorphic lithology. Slope gradients range from 50 percent to near

vertical. Soils on these landforms are shallow to moderately deep, weakly

developed gravelly loams and sandy loams with cobbly sand substrata. These

soils are classified as Dystric Cryochrepts and Entic Cryumbrepts. Rock outcrop

may be 50 percent of the unit. The dominant potential natural vegetation is

subalpine fir, whitebark pine/subalpine fir, and herbaceous or shrub dominated

openings.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 93
LTA40-M332A

STEEP GLACIATED MOUNTAIN SLOPES: METASEDIMENTARY (BELT)

Location: This unit is located in the Bitterroot Mountains of Idaho west of

the Montana border in the upper Lochsa River Basin.

 Acreage by Section

 40-M332A 4,758

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a steep, alpine

glacial landscape setting, which is typically composed of steep glacial slopes

and headwalls. Parent materials are Mazama volcanic ash underlain by Belt

Series metasediments composed of quartizites, siltites, and argillites. 

Accessory Characteristics: The primary soils are shallow to moderately deep

with textures ranging from silt loam to loam surface textures and very gravelly

to cobbly loam subsurface layers. The vegetation is a mosaic of coniferous

forest, subalpine meadows, and rock outcrops. Mean annual precipitation ranges

from 102 to 165 cms. (40 to 65 inches). The elevation range is 1524 to 2134

meters (5000 to 7000 feet). The dominant slopes have gradients of 30 to 60

percent. This unit is moderate to highly dissected by streams, with the

dominant stream pattern being parallel. Wetlands and subalpine ponds are a

major component of this unit.

LTA Components: This landtype association consists of a complex of steep,

alpine glaciated slopes and headwalls intermixed across the landscape.

Steep, alpine, glaciated slopes and headwalls are formed in Belt Series

metasediments with a mixed surface layer of Mazama volcanic ash of varying

thickness. Slope gradients range from 30 to 60 percent. Soils on these

landforms are shallow to moderately deep, weakly to moderately developed, and

consist mostly of silt loam and loam surface textures and very gravelly,

cobbly, and bouldery loamy subsurface textures. These soils are classified as

Andic Cryochrepts, Dystric Cryochrepts, and Vitric Haplocryands. Rock outcrop

occurs on 20 to 50 percent of this landscape component. The dominant potential

natural vegetation are subalpine fir, whitebark pine, and wet grass/sedge

meadows.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 94
LTA41-M332A

STEEP GLACIATED MOUNTAIN SLOPES: GRANITICS

Location: This unit occurs in the Bitterroot Mountain Range, within the

Salmon and Clearwater River basins in central Idaho.

 Acreage by Section

 41-M332A 401,415

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs on steep and very steep

alpine glacial landscape settings. Parent material is colluvium, residuum, and

scattered alpine glacial till, derived from granitic sources.

Accessory Characteristics: The primary soils are shallow to deep, coarse

textured, and contain numerous rock fragments throughout the profile.

Additionally, avalanche chutes, rock outcrop, and rubble land are major

components to this map unit. The vegetation is a mosaic of closed to open

coniferous forest, and moist shrublands. Mean annual precipitation ranges from

46 to 178 cms. (18 to 70 inches). The elevation range is 1219 to 2896 meters

(4000 to 9500 feet). The dominant slopes have gradients of 15 to 100 percent.

This unit is moderately to highly dissected by streams, with the dominant

stream pattern being parallel. Wetlands (wet sidehills and avalanche chutes),

lakes, and ponds are major components of this unit.

LTA Components: This landtype association consists of glacial trough walls,

alpine ridges, and cirques (headwalls and basins).

Glacial trough walls were formed by alpine glacial scouring. After the

glaciers retreated the walls were further modified by avalanches creating

avalanche chutes. Slope gradients range from 50 to 100 percent and slope shape

is straight to concave. Soils on this landform are shallow to deep and poorly

to somewhat excessively drained. These soils are weakly developed, and consist

of very cobbly loam or gravelly sandy loam surfaces overlying very cobbly loamy

sand or very cobbly sandy loam substrata. The dominant soils are classified

as: Lithic Cryochrepts, Andic Cryochrepts, Dystric Cryochrepts, Lithic

Ustochrepts, and Typic Ustochrepts. Typic Cryaquands comprise extensive areas

on northerly aspects in the headwater portions of these troughs. Rock outcrop,

rubbleland, and avalanche chutes occupy about 45 percent of this component.

The most common potential natural vegetation series are Douglas-fir and grand

fir at moderate elevations, and subalpine fir and alpine larch-subalpine fir at

higher elevations. Avalanche chutes have a sitka alder community type. The

Typic Cryaquands soils that occur in the headwaters portion of trough walls

support sitka alder. This landform component represents about 60 percent of

this unit.

Cirque headwalls and basins were formed by alpine glacial erosion. Cirque

basins have slope gradients of 15 to 60 percent and slope shapes are convex to

concave. Cirque headwalls have slope gradients greater than 60 percent

(approaching vertical) and slope shapes are concave. Soils on this landform

are shallow to very deep, and very poorly drained to well drained. These soils

are weakly developed and consist of extremely bouldery silt loam volcanic ash

surfaces over very cobbly loamy sand substrata. The dominant soils on cirque

headwalls are classified as Andic Cryochrepts and Lithic Cryochrepts. Soils on

cirque basins are classified as Typic Cryandepts and Histic Cryaquepts. Rock

outcrop, talus, and scree occupy about 40 percent of this component. The

dominant natural vegetation series are: alpine larch-subalpine fir, whitebark

pine-subalpine fir, and subalpine fir. Holm's Rocky Mountain sedge and beaked

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 95
sedge occur on very poorly drained to ponded alluvial basins. This landform

represents about 25 percent of this unit.

Alpine ridges were formed by alpine glacial scouring and/or strong periglacial

frost shattering of exposed bedrock. Slope gradients range from 50 to 80

percent and slope shape is convex. Soils on this landform are shallow and

somewhat excessively drained. These soils are weakly developed and consist of

very stony sandy loam surfaces overlying extremely stony loamy sand substrata.

Bedrock occurs at a depth of less than 20 inches. The dominant soil is

classified as Lithic Cryorthents; however, only about 20 percent of this

landform has a soil cover. Rock outcrop, talus, and scree occupy about 80

percent of this component. The most common plant associations are alpine

larch-subalpine fir and whitebark pine-subalpine fir. This landform represents

about 15 percent of this unit.

Compiled by: Bob Spokas, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 96
LTA45-M332A

WEAKLY GLACIATED MOUNTAIN SLOPES AND RIDGES: GRANITICS

Location: This unit is located in the Bitterroot Mountain Range in the Upper

Selway River Basin of central Idaho.

 Acreage by Section

 45-M332A 71,072

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a high elevation

broad ridgetop position which is typically composed of weakly expressed

glaciated slopes and basins that were formed by ice cap glaciers, minor valley

glaciers, and strong periglacial frost shattering. Parent materials are a

complex of frost shattered residuum and colluvium, intermixed with glacial till

derived from moderately weathered granite.

Accessory Characteristics: The primary soils are shallow and very deep, coarse

soils with numerous rock fragments and have a volcanic ash surface layer. The

vegetation is a mosaic of coniferous forest, stunted, wind-deformed forest, and

occasional small wet meadows. Mean annual precipitation ranges from 102 to 140

centimeters (40 to 55 inches). The elevation range is 2073 to 2591 meters

(6800 to 8500 feet). The dominant slopes have gradients of 20 to 55 percent.

This unit is slightly dissected by streams, with the dominant stream pattern

being dendritic. Wetlands and ponds are a minor component of this unit.

LTA Components: This landtype association consists of weakly developed glacial

cirques, and frost shattered mountain ridgetops.

Weakly developed glacial cirques are formed in residuum, colluvium, and till

derived from a variety of rock types. Slope gradients range from 20 to 55

percent. Soils on this landform are shallow to very deep and somewhat

excessively drained. These soils are weakly developed and consist of extremely

bouldery loam volcanic ash surface layers overlying very stony loamy sand

substrata. The dominant soils are classified as Lithic and Andic Cryochrepts.

Rock outcrop occurs on about 10 percent of this landscape component. The

dominant potential natural vegetation is alpine larch-subalpine fir, whitebark

pine-subalpine fir, and subalpine fir series. This component represents 65

percent of this unit.

Frost shattered mountain ridgetops are formed in residuum and colluvium. Slope

gradients range from 20 to 50 percent. Soils on this landform are shallow to

very deep and somewhat excessively drained. These soils are weakly developed

and consist of very stony loam volcanic ash surface layers overlying very

cobbly coarse sandy loam substrata. The dominant soils are classified as

Lithic and Andic Cryochrepts. Rock outcrop occurs on about 15 percent of this

landscape component. The dominant potential natural vegetation is whitebark

pine-subalpine fir, alpine larch-subalpine fir, and subalpine fir series. This

component represents 35 percent of this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 97
LTA46-M332A

ALPINE TROUGHS AND TROUGHWALLS: GRANITIC

Location: This unit is located in the Bitterroot Mountains of Idaho in the

upper Lochsa and Selway River Basins.

 Acreage by Section

 46-M332A 35,567

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs at higher elevations,

in a gentle to steep, alpine glacial landscape setting, which is typically

composed of alpine trough bottoms and troughwalls. Parent materials are Mazama

volcanic ash overlying weakly weathered granitic tills and bedrock of the Idaho

Batholith.

Accessory Characteristics: The primary soils are shallow to moderately deep

with textures ranging from silt loam to loam surface textures and very gravelly

to cobbly loam subsurface layers. The vegetation is a mosaic of coniferous

forest and rock outcrops. Mean annual precipitation ranges from 127 to 203 cms

(50 to 80 inches). The elevation range is 1219 to 1981 meters (4000 to 6500

feet). The dominant slopes have range from 1 percent in the trough bottoms to

more than 60 percent on the troughwalls. This unit is moderate to highly

dissected by streams, with the dominant stream pattern being parallel.

Wetlands and moist seeps a major component of this unit.

LTA Components: This landtype association consists of glacial troughwalls, and

glacial trough bottoms.

The glacial troughwalls are formed in granitics of the Idaho Batholith with a

mixed surface layer of Mazama volcanic ash of varying thickness. Slope

gradients range from 40 to more than 60 percent. Soils on these landforms are

shallow to moderately deep, weakly to moderately developed, and consist mostly

of silt loam and loam surface textures and very gravelly, cobbly, and bouldery

loamy subsurface textures. These soils are classified as Andic Cryochrepts,

Typic Cryochrepts, and Dystric Cryochrepts. Rock outcrop occurs on 10 to 30

percent of this landscape component. The dominant potential natural vegetation

are subalpine fir, grand fir, and alder communities in moist seeps. This

component represents about 70 percent of this unit.

The trough bottoms consist of glacial tills and glacio-fluvial materials from

Idaho Batholith granitics with a mixed surface layer of Mazama volcanic ash of

varying thickness. Slope gradients range from 1 to 30 percent. Soils on these

landforms are moderately deep, weakly to moderately developed, and consist

mostly of silt loam and loam surface textures and mostly unstratified very

gravelly, and cobbly, loamy subsurface textures. These soils are classified as

Andic Cryochrepts, Dystric Cryochrepts, and Typic Haplocryands. Rock outcrops

are uncommon. The dominant potential natural vegetation are subalpine fir,

grass/sedge associations, and alder communities in moist seeps and wetlands.

This component represents about 30 percent of this unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 98
LTA47-M332A

ALPINE TROUGHS AND TROUGHWALLS: METASEDIMENTARY (BELT)

Location: This unit is located in the Bitterroot Mountains of Idaho in the

upper Lochsa River Basin.

 Acreage by Section

 47-M332A 6,809

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs at higher elevations,

in a gentle to steep, alpine glacial landscape setting, which is typically

composed of alpine trough bottoms and troughwalls. Parent materials are Mazama

volcanic ash overlying weakly weathered Belt series tills and bedrock.

Accessory Characteristics: The primary soils are shallow to moderately deep

with textures ranging from silt loam to loam surface textures and very gravelly

to cobbly loam subsurface layers. The vegetation is a mosaic of coniferous

forest and rock outcrops. Mean annual precipitation ranges from 127 to 203 cms.

(50 to 80 inches). The elevation range is 1219 to 1981 meters (4000 to 6500

feet). The dominant slopes have range from 1 percent in the trough bottoms to

more than 60 percent on the troughwalls. This unit is moderate to highly

dissected by streams, with the dominate stream pattern being parallel.

Wetlands and moist seeps are a major component of this unit.

LTA Components: This landtype association consists of glacial troughwalls, and

glacial trough bottoms.

The glacial troughwalls are formed in Belt metasediments with a mixed surface

layer of Mazama volcanic ash of varying thickness. Slope gradients range from

40 to more than 60 percent. Soils on these landforms are shallow to moderately

deep, weakly to moderately developed, and consist mostly of silt loam and loam

surface textures and very gravelly, cobbly, and bouldery loamy subsurface

textures. These soils are classified as Andic Cryochrepts, Typic Cryochrepts,

and Dystric Cryochrepts. Rock outcrop occurs on 10 to 30 per cent of this

landscape component. The dominant potential natural vegetationare subalpine

fir, grand fir, and alder communities in moist seeps. This component

represents about 65 percent of this unit.

The trough bottoms consist of glacial tills and glaciofluvial materials from

Belt metasediments with a mixed surface layer of Mazama volcanic ash of varying

thickness. Slope gradients range from 1 to 30 percent. Soils on these

landforms are moderately deep, weakly to moderately developed, and consist

mostly of silt loam and loam surface textures and mostly unstratified very

gravelly, and cobbly, loamy subsurface textures. These soils are classified as

Andic Cryochrepts, Dystric Cryochrepts, and Typic Haplocryands. Rock outcrops

are uncommon. The dominant potential natural vegetation are subalpine fir,

grass/sedge associations, and alder communities in moist seeps and wetlands.

This component represents about 25 percent of this unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 99
LTA51-M332A

GLACIATED MOUNTAIN SLOPES: GRANITICS

Location: This unit is located in the Bitterroot Mountain Range and occurs in

the Selway River Basin of central Idaho.

 Acreage by Section

 51-M332A 281,987

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs on gently to moderately

sloping glacial landscape settings. Parent material is alpine glacial till,

alluvium, and residuum derived from granitic sources.

Accessory Characteristics: The primary soils are deep and very deep with

coarse to moderately coarse textures. Small inclusions of shallow soils, rock

outcrop, and rubble land can also be found within this unit. The vegetation is

a mosaic of moderately dry, moist, and wet (riparian types) coniferous forest.

Mean annual precipitation ranges from 76 to 127 centimeters (30 to 50 inches).

The elevation range is 1372 to 2256 meters (4500 to 7400 feet). Slope

gradients range from 1 to 50 percent. This unit is slightly to moderately

dissected by streams, with the dominant stream pattern being parallel.

Wetlands, seeps, bogs and riparian zones are major components of this unit.

LTA Components: This landtype association consists of glacial moraines, and

floodplains.

Glacial moraines were formed by alpine glacial till. Slope gradients range

from 8 to 50 percent and slope shape is convex. Soils on this landform are

shallow to deep, and moderately well to somewhat excessively drained. These

soils are weakly developed and consist of bouldery loam volcanic ash surface

layers overlying very cobbly loamy sand substrata. The dominant soils are

classified as: Andic Cryochrepts, Lithic Cryochrepts, Lithic Ustochrepts, and

Typic Ustochrepts. Rock outcrop and rubble land occupy about 10 percent of

this component. The dominant potential natural vegetation are subalpine fir

and Douglas-fir series. This landform component represents about 75 percent of

this unit.

Floodplains were formed in coarse alluvium. Slope gradients range from 1 to 8

percent. Soils on this landform are very deep and moderately well to very

poorly drained. These soils are very weakly develop and consist of cobbly loam

surface layers overlying very cobbly loamy sand substrata. The dominant soils

are classified as Typic Cryaquents, Oxyaquic Cryofluvents, and Andic

Cryofluvents. Rock outcrop occurs on less than 5 percent of this component.

The dominant potential natural vegetation is wester redcedar, grand fir and

subalpine fir. This landform represents about 25 percent of this unit.

Compiled by: Bob Spokas, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 100
LTA57-M332A

LTA57-M333D

GLACIATED MOUNTAIN SLOPES:

GNEISSES, QUARTZITES, AND SCHISTS

Location: This unit is located in mid to high elevation glaciated areas of

north central Idaho in the Salmon and Clearwater River basins.

 Acreage by Section

 57-M332A 54,631

 57-M333D 9,130

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is composed of gently to

moderately sloping alpine glaciated lands, including moraines, cirque basins,

and trough bottoms. Parent materials are poorly weathered gneiss, quartzite,

and schist associated with the Idaho batholith.

Accessory Characteristics: The primary soils are deep to very deep silt loams,

loams and sandy loams. The vegetation is coniferous forest. Mean annual

precipitation ranges from 89 to 127 centimeters (35 to 50 inches). The

elevation range is 1700 to 2500 meters (5500 to 8200 feet). The dominant

slopes have gradients of 10 to 50 percent. This unit is moderately dissected

by streams, with the dominant stream pattern being pinnate. Wetlands and lakes

are significant inclusions in basins and depressions.

LTA Components: This landtype association consists of moraines, cirque basins,

and trough bottoms.

Moraines are formed in volcanic ash influenced loess and glacial till o f felsic

metamorphic lithology. Slope gradients range from 5 to 50 percent. Soils on

these landforms are moderately deep to very deep, weakly developed sil t loams

and gravelly sandy loams with cobbly loamy sand substrata. These soils are

classified as Andic Cryochrepts and Dystric Cryochrepts, and Andic

Cryumbrepts. Rock outcrop is less than 15 percent of the unit. The dominant

potential natural vegetation at mid elevations is grand fir, and at high

elevations subalpine fir. This component is 60 percent of the map unit.

Cirque basins are formed in volcanic ash influenced loess and glacial till of

felsic metamorphic lithology. Slope gradients range from 1 to 30 percent.

Soils on these landforms are moderately deep to very deep, weakly developed

silt loams and gravelly sandy loams with very cobbly loamy sand substrata.

These soils are classified as Andic Cryochrepts and Entic Cryumbrepts. Rock

outcrop is less than 10 percent of the unit. The dominant potential natural

vegetation is subalpine fir and sedge/shrub complexes. This component is 20

percent of the map unit.

Trough bottoms are formed in mixed volcanic ash influenced loess, glacial till

and stratified outwash of felsic metamorphic lithology. Slope gradients range

from 1 to 30 percent. Soils are these landforms are deep to very deep, weakly

developed silt loams, and gravelly sandy loams with very cobbly loamy sand or

sand substrata. These soils are classified as Andic Cryochrepts, Entic

Cryumbrepts, and Andic Cryaquepts. The dominant potential natural vegetation

is subalpine fir, grand fir and sedge/shrub complexes. This component is 20

percent of the map unit.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 101
LTA59-M332A

MOUNTAIN SLOPES AND RIDGES: GNEISSES, QUARTZITES AND SCHISTS

Location: This unit is located in mountains and canyons of north central Idaho

and central Idaho in the Salmon and Clearwater River basins.

 Acreage by Section

 59-M332A 129,742

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is colluvial mountain slopes.

Parent materials are moderately weathered gneiss, schist and quartzite

associated with the Idaho batholith.

Accessory Characteristics: The primary soils are deep to very deep silt loams,

loams and sandy loams. The vegetation is dominantly coniferous forest, with

some grassland at low elevations on south aspects. Mean annual precipitation

ranges from 64 to 114 centimeters (25 to 45 inches). The elevation range is

700 to 2000 meters (2300 to 6500 feet). The dominant slopes have gradients of

35 to 50 percent. This unit is moderately dissected by streams, with the

dominant stream pattern being parallel. 

LTA Components: This landtype association consists of mountain slopes.

Mountain slopes are formed in volcanic ash influenced loess, residuum and

colluvium of felsic lithology. Soils on these landforms are deep to very deep,

moderately developed silt loams, loams and sandy loams with sandy or

substrata. Soils on low elevations on south aspects are Ultic Haploxerolls.

At mid elevations soils are classified as Andic Dystrochrepts and Typic

Dystrochrepts, and at high elevations they are Andic Cryochrepts and Dystric

Cryochrepts. Rock outcrop is less than 25 percent of the unit. The dominant

potential natural vegetation at low elevations is bluebunch wheatgrass, at mid

elevations, Douglas-fir and grand fir, and at high elevations - subalpine fir.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 102
LTA60-M332A

MOUNTAIN SLOPES AND RIDGES: METASEDIMENTARY (BELT)

Location: This unit is located in the Bitterroot Mountain Range of central

Idaho in the Upper Salmon and Upper Selway River Basins.

 Acreage by Section

 60-M332A 63,800

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a non glaciated steep

mountain slope setting, below the zone of strong frost shattering, which is

typically composed of moderately dissected mountain slopes, ridge tops, and

narrow valley bottoms. Parent materials are colluvium and residuum underlain

by precambrian belt rocks such as argillite, quartzite, and siltite.

Accessory Characteristics: The primary soils are shallow to deep,

medium-textured, and have numerous rocks fragments throughout the profile. The

vegetation is a mosaic of coniferous forest and native grasslands. Mean annual

precipitation ranges from 64 to 89 centimeters (25 to 35 inches). The

elevation range is 1463 to 1951 meters (4800 to 6400 feet). The dominant

slopes have gradients of 10 to 55 percent. This unit is moderately dissected

by streams, with the dominant stream pattern being dendritic. Wetlands are a

minor component of this unit.

LTA Components: This landtype association consists of mountain slopes, and

ridge tops.

Mountain slopes are formed in colluvium and residuum. Slope gradients range

from 35 to 55 percent. Soils on this landform are shallow to very deep and

well drained. Soils are weakly developed in areas underlain by the

coarse-textured rock types, such as quartzite, and having cooler forested

habitat types. These soils have gravelly fine sandy loam surface layers and

extremely cobbly fine sandy loam substrata. Soils that formed in material

derived from fine-textured rocks, such as argillite, and having warmer forested

or grassland series are well developed. These soils have gravelly loam surface

layers and very cobbly sandy clay loam or clay loam substrata. The dominant

soils are classified as Typic and Lithic Ustochrepts, Dystric Cryochrepts,

Typic Eutroboralfs and Lithic Argiborolls. Rock outcrop occurs on about 5

percent of this landscape component. The dominant potential natural vegetation

is Douglas-fir, grand fir, Idaho fescue and subalpine fir. This component

represents 75 percent of this unit.

Mountain ridge tops are formed in residuum. Slope gradients range from 10 to

35 percent. Soils on this landform are shallow to deep and well drained.

These soils are similar to those described above for the mountain slopes

landscape component. Rock outcrop occurs on about 20 percent of this landscape

component. The dominant potential natural vegetation is Douglas-fir and Idaho

fesuce series. This component represents 20 percent of this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 103
LTA61-M332A

MOUNTAIN SLOPES AND RIDGES: HIGHLY WEATHERED GRANITICS

Location: This unit is located in the Clearwater and Bitterroot Mountains of

Idaho in the upper Selway and Lochsa River Basins.

 Acreage by Section

 61-M332A 95,759

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a moderately sloping

mountain slope and ridge landscape setting, which is typically composed of

moderately to highly dissected mountain slopes and ridgetops. Parent materials

are a surface layer of Mazama volcanic ash underlain by highly weathered

granitics of the Idaho Batholith.

Accessory Characteristics: The primary soils are moderately deep to deep with

silt loam to loam and sandy loam surface textures and very gravelly to cobbly

loam to sandy loam subsurface layers. The vegetation is a mosaic of coniferous

forest. Mean annual precipitation ranges from 64 to 178 cms (25 to 70 inches).

The elevation range is 1219 to 2134 meters (4000 to 7000 feet). The dominant

slopes have gradients of 30 to 60 percent. This unit is moderately to highly

dissected by streams, with the stream pattern being dendritic to trellis.

Wetlands and moist seeps are a common component of this unit.

LTA Components: This landtype association consists of steep mountain slopes,

and ridge tops.

Steep mountain slopes are formed in granitic colluvium overlain by Mazama

volcanic ash. In the southern portions of this Section many slopes, especially

those with southerly to westerly aspects, lack a volcanic ash surface layer.

Slope gradients range from 30 to 60 percent. Soils on these landforms are

moderately deep to very deep, moderately to highly developed, and consist of

silt loam, sandy loam and loam surface textures with gravelly loam to sandy

loam subsurface textures. These soils are classified as Andic Dystrochrepts,

Typic Dystrochrepts, and Typic Udivitrand. In the southern portion of this

Section, soils are colder and drier and have very gravelly to verycobbly loamy

sand textured substrata and are classified as Typic Ustochrepts and Dystric

Cryochrepts. Rock outcrop occurs on about 5 percent of this landscape

component. The dominant potential natural vegetation is western redcedar and

grand fir in moister climates and is moderately dry to dry Douglas-fir and

subalpine fir in the drier climates to the south. This component represents 80

percent of this unit.

Ridgetops are formed in granitic residuum and colluvium overlain by a mixed

layer of Mazama volcanic ash. Slope gradients range from 15 to 50 percent.

Soils on these landforms are shallow to deep, moderately developed, and consist

of silt loam, loam and gravelly sandy loam surface textures with gravelly to

cobbly loam or sandy loam subsurface textures. These soils are classified as

Andic Dystrochrepts, Typic Dystrochrepts, and Typic Udivitrand. In the

southern portions of this Section, the soils have very gravelly or very cobbly

loamy sand substrata and are classified as Typic Ustochrepts and Dystric

Cryochrepts. Rock outcrop occurs on about 10 percent of this landscape

component. The dominant potential natural vegetation is western redcedar,

grand fir, and Douglas-fir. The subalpine fir series also occurs in the

southern part of this Section. This component represents 20 percent of this

unit.

Compiled by: Jim Mital, Clearwater National Forest, and Ken McBride,

Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 104
LTA62-M332A

MOUNTAIN SLOPES AND RIDGES: WEAKLY WEATHERED GRANITICS

Location: This unit is located in the Clearwater and Bitterroot Mountain

Ranges of north central Idaho in the Clearwater and Salmon River basins.

 Acreage by Section

 62-M332A 129,836

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a nonglaciated steep

mountain slope landscape setting, below the zone of strong frost shattering,

and is typically composed of moderately dissected mountain slopes, ridge tops,

and minor amounts of narrow valley bottoms. Parent materials arecolluvium and

residuum underlain by weakly weathered granitic and gneissic bedrock.

Accessory Characteristics: The primary soils are shallow to very deep,

moderately coarse textured, and have numerous rock fragments throughout the

profile. The vegetation is a mosaic of coniferous forest, native grasslands,

and dry shrublands. Mean annual precipitation ranges from 64 to 114 cms (18 to

45 inches). The elevation range is 860 to 2073 meters (2300 to 6800 feet).

The dominant slopes have gradients of 20 to 55 percent. This unit is

moderately dissected by streams. Low order streams are parallel and higher

order streams are dendritic in pattern. Wetlands are a minor component of this

unit.

LTA Components: This landtype association consists of mountain slopes and

ridge tops.

Mountain slopes are formed in colluvium and residuum. Slope gradients range

from 35 to 55 percent. Soils on this landform are shallow to very deep and

somewhat excessively drained or well drained. These soils are weakly developed

except that on warm, southeast to west-facing slopes, soils have a more

developed, clay enriched subsoil. The weakly developed soils consist of

gravelly sandy loam surface layers overlying very cobbly sandy loam substrata.

The more developed soils have a gravelly sandy loam surface layer that overlies

very gravelly or very cobbly sandy clay loam substrata. The dominant soils are

classified as Typic and Lithic Ustochrepts; Ultic Haploxerolls; Typic

Dystrochrepts; Dystric Cryochrepts; Typic Eutroboralfs, and Lithic

Argiborolls. Rock outcrop occurs on about 10 percent of this landscape

component. The dominant potential natural vegetation is Douglas-fir, Idaho

fescue, grand fir and subalpine fir series. This component represents 80

percent of this unit.

Mountain ridge tops are formed in residuum. Slope gradients range from 20 to

35 percent. Soils on this landform are moderately deep to deep and well

drained. Soil textures and degree of soil development are similar to those

listed above for the mountain slopes landscape position. These soils are

Lithic Ustochrepts, Lithic Argiborolls, Andic Dystrochrepts, Andic Cryochrepts,

and Dystric Cryochrepts. Rock outcrop occurs on about 20 percent of this

landscape component. The dominant potential natural vegetation is Douglas-fir,

grand fir, subalpine fir, and Idaho fescue series. This component represents

15 percent of this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 105
LTA63-M332A

MOUNTAIN SLOPES AND RIDGES: SCHIST AND GNEISS

Location: This unit is located in the Clearwater Mountains of Idaho in the

lower Selway and Lochsa River Basins.

 Acreage by Section

 63-M332A 96,467

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a moderately sloping

mountain slope and ridge landscape setting, which is typically composed of

moderately dissected mountain slopes and ridgetops. Parent materials are a

surface layer of Mazama volcanic ash underlain by schist and gneiss with high

amounts of mica.

Accessory Characteristics: The primary soils are moderately deep to very deep

with silt loam to loam surface textures and gravelly loam subsurface layers.

The vegetation is a mosaic of coniferous forest. Mean annual precipitation

ranges from 30 to 50 inches (76 to 127 cms.) The elevation range is 2500 to

6000 feet (762 to 1829 meters). The dominant slopes have gradients of 30 to 60

percent. This unit is moderately to highly dissected by streams, with the

stream pattern being dendritic to trellis. Wetlands and moist seeps are a

common component of this unit.

LTA Components: This landtype association consists of steep mountain slopes,

and ridge tops.

Steep mountain slopes are formed in schist and gneiss colluvium overlain by

Mazama volcanic ash. Slope gradients range from 30 to 60 percent. Soils on

these landforms are moderately deep to very deep, highly developed, and consist

of silt loam to loam surface textures with gravelly loam subsurface textures.

These soils are classified as Andic Dystrochrepts, Andic Xerochrepts, and

Vitric Hapludands. Rock outcrop occurs on about 5 percent of this landscape

component. The dominant potential natural vegetation is western redcedar and

grand fir. This component represents 80 percent of this unit.

Ridgetops are formed in gneiss and schist residuum and colluvium overlain by a

mixed layer of Mazama volcanic ash. Slope gradients range from 15 to 50

percent. Soils on these landforms are shallow to deep, moderatelyto highly

developed, and consist of silt loam to loam surface textures with gravelly to

cobbly loam subsurface textures. These soils are classified as Andic

Dystrochrepts, Andic Xerochrepts, and Vitric Hapludands. Rock outcrop occurs

on about 10 percent of this landscape component. The dominant potential

natural vegetation is western redcedar, grand fir, and Douglas-fir. This

component represents 20 percent of this unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 106
LTA64-M332A

MOUNTAIN SLOPES AND RIDGES: VOLCANICS

Location: This unit is located in the Bitterroot Mountain Range of central

Idaho in the Selway River Basin.

 Acreage by Section

 64-M332A 18,316

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a non-glaciated steep

mountain slope landscape setting, below the zone of strong frost shattering,

which is typically composed of steep mountain slopes, moderately steep ridge

tops, and minor amounts of narrow valley bottoms. Parent materials are

colluvium and residuum underlain by volcanic andesites and rhyolites.

Accessory Characteristics: The primary soils are shallow to very deep with

loamy textures and numerous rock fragments throughout the profile. The

vegetation is a mosaic of coniferous forest and dry native grasslands. Mean

annual precipitation ranges from 51 to 102 centimeters (20 to 40 inches). The

elevation range is 1524 to 2012 meters (5000 to 6600 feet). The dominant

slopes have gradients of 20 to 55 percent. This unit is moderately dissected

by streams, with the dominant stream pattern being dendritic. Wetlands are a

minor component of this unit.

LTA Components: This landtype association consists of steep mountain slopes,

and moderately steep ridge tops.

Steep mountain slopes are formed in colluvium derived from andesite or

rhyolite. Slope gradients range from 30 to 55 percent. Soils on this landform

are deep and well drained. These soils mostly are well developed and consist

of gravelly loam or sandy loam surface layers overlying very gravelly or very

cobbly sandy clay loam substrata. Similar soils are less well developed and

generally have very cobbly sandy loam substrata. The dominant soils are

classified as Typic Cryoboralfs, Typic Eutroboralfs, Typic Ustochrepts, and

Lithic Argiborolls. Rock outcrop occurs on about 5 percent of this landscape

component. The dominant potential natural vegetation is subalpine fir,

Douglas-fir and Idaho fescue. This component represents 75 percent of this

unit.

Mountain ridge tops and associated spur ridges are formed in residuum and

colluvium derived from andesite or rhyolite. Slope gradients range from 20 to

30 percent. Soils on this landform are mostly shallow to moderately deep and

well drained. These soils are a mix of weakly developed and well developed

soils and consist of gravelly loam surface layers overlying very gravelly or

very cobbly sandy loam or sandy clay loam substrata. The dominant soils are

classified as Lithic Ustochrepts, Typic Cryoboralfs, and Typic Eutroboralfs.

Rock outcrop occurs on about 15 percent of this landscape component. The

dominant potential natural vegetation is Douglas-fir and subalpine fir

series. This component represents 15 percent of this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 107
LTA70-M332A

FROST SHATTERED MOUNTAIN RIDGE TOPS: METASEDIMENTARY (BELT)

Location: This unit is located in the Bitterroot Mountain Range of central

Idaho in the Selway River Basin.

 Acreage by Section

 70-M332A 1,385

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a high elevation

mountain ridge landscape setting which is typically composed of frost shattered

ridge tops and mountain slopes. Parent materials are colluvium and residuum

underlain by Precambrian sedimentary Belt rocks.

Accessory Characteristics: The primary soils are deep with fine sandy loam

textures that have numerous rock fragments in the profile. The vegetation is a

fairly uniform cover of coniferous forest. Mean annual precipitation ranges

from 114 to 152 centimeters (45 to 60 inches). The elevation range is 2012 to

2378 meters (6600 to 7800 feet). The dominant slopes have gradients of 10 to

50 percent. This unit is slightly dissected by streams, with the dominant

stream pattern being dendritic. Wetlands are a minor component of this unit.

Small areas of glaciation are also included in this unit.

LTA Components: This landtype association consists of frost shattered mountain

slopes, and ridge tops.

Frost shattered mountain slopes formed in colluvium derived from Belt rocks

such as quartzite, argillite, and siltite. A thin layer of volcanic ash

overlies this colluvium in most of the area. Slope gradients range from 35 to

50 percent. Soils on this landform are deep and well drained. These soils are

weakly developed and consist of gravelly or cobbly loam or silt loam surface

layers and very cobbly to extremely cobbly fine sandy loam substrata. The

dominant soils are classified as Andic Cryochrepts and Dystric Cryochrepts.

Rock outcrop occurs on about 10 percent of this landscape component. The

dominant potential natural vegetation includes subalpine fir and whitebark

pine-subalpine fir series. This component represents 60 percent of this unit.

Frost shattered ridge tops formed in residuum and colluvium from quartzite,

argillite, and siltite that also has a thin veneer of volcanic ash loess at the

surface. Slope gradients range from 10 to 30 percent. Soils on this landform

are deep and well drained. These soils are poorly developed and consist of

cobbly to extremely cobbly loam or silt loam surface layers that overlie

extremely cobbly fine sandy loam substrata. The dominant soils are classified

as Andic Cryochrepts and Dystric Cryochrepts. Rock outcrop occurs on about 5

percent of this landscape component. The dominant potential natural vegetation

includes subalpine fir and whitebark pine-subalpine fir series. This component

represents 30 percent of this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 108
LTA71-M332A

FROST SHATTERED MOUNTAIN RIDGE TOPS: HIGHLY WEATHERED GRANITICS

Location: This unit is located in the Bitterroot and Clearwater Mountain

Ranges of central Idaho in the Selway and Lochsa River Basins.

 Acreage by Section

 71-M332A 62,411

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a high elevation

mountain ridge landscape setting which is typically composed of frost shattered

ridge tops and mountain slopes. Parent materials are Mazama volcanic ash over

colluvium and residuum underlain by highly weathered granitic rocks.

Accessory Characteristics: The primary soils are moderately deep to deep with

loamy to sandy loam surface textures and gravelly loam and sandy subsurface

textures. There are numerous pea-sized and cobble-sized rock fragments in the

profile. The vegetation is a fairly uniform cover of coniferous forest. Mean

annual precipitation ranges from 76 to 152 cms. (30 to 60 inches). The

elevation range is 1372 to 2500 meters (4500 to 8200 feet). The dominant

slopes have gradients of 10 to 55 percent. This unit is slightly dissected by

streams, with the dominant stream pattern being dendritic. Wetlands are a

minor component of this unit. Small areas of glaciation are included.

LTA Components: This landtype association consists of frost shattered mountain

slopes, and ridge tops.

Frost shattered mountain slopes are formed in a layer of wind deposited

volcanic ash that overlies colluvium derived from highly weathered granitic

rocks. Slope gradients range from 30 to 55 percent. Soils on this landform

are deep and somewhat excessively drained. These soils are weakly developed

and consist of gravelly sandy loam, loam or silt loam surface layers and very

gravelly loamy sand or coarse sandy loam substrata. The dominant soils are

classified as Andic Cryochrepts, Dystric Cryochrepts, and Typic Haplocryands..

Bedrock is highly weathered granitics (grus). Rock outcrop varies from less

than 5 percent of this landscape component in the eastern part of the area to

around 10 percent in the western part. The dominant potential natural

vegetation is subalpine fir and whitebark pine-subalpine fir series. This

component represents 70 percent of this unit.

Frost shattered ridge tops are formed in residuum and colluvium derived from

highly weathered granitic rocks overlain by volcanic ash loess. Slope

gradients range from 10 to 40 percent. Soils on this landform are deep and

somewhat excessively drained. These soils are poorly developed and consist of

gravelly loam, sandy loam, or silt loam surface layers that overlie very

gravelly loamy sand or coarse sandy loam substrata. The dominant soils are

classified as Andic Cryochrepts, Dystric Cryochrepts and Typic Cryochrepts.

Bedrock is highly weathered granitics. Rock outcrop occurs on less than 5

percent of this landscape component in the eastern areas and up to 20 percent

in the west. The dominant potential natural vegetation is subalpine fir, and

whitebark pine-subalpine fir series. This component represents 25 percent of

this unit.

Compiled by: Ken McBride, Bitterroot National Forest, and Jim Mital,

Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 109
LTA72-M332A

FROST SHATTERED MOUNTAIN RIDGE TOPS: WEAKLY WEATHERED GRANITICS

Location: This unit is located in the Clearwater and Bitterroot Mountain

Ranges of central Idaho in the Clearwater and Salmon River basins.

 Acreage by Section

 72-M332A 177,263

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a high elevation

mountain ridge landscape setting which is typically composed of frost-churned

ridge tops and mountain slopes. Parent materials are colluvium and residuum

underlain by weakly weathered granitic rocks.

Accessory Characteristics: The primary soils are deep with silt loam to sandy

loam textures that have numerous rock fragments in the profile. The vegetation

is a fairly uniform cover of coniferous forest. Mean annual precipitation

ranges from 76 to 140 cms (30 to 55 inches). The elevation range is 5300 to

8300 feet (1600 to 2530 meters). The dominant slopes have gradients of 15 to

50 percent. This unit is slightly dissected by streams, with the dominant

stream pattern being parallel, but grading to weakly dendritic. Wetlands are a

minor component of this unit. Small areas of glaciation are included in this

map unit.

LTA Components: This landtype association consists of frost shattered mountain

slopes, and ridge tops.

Frost shattered mountain slopes are formed in a thin layer of wind- deposited

volcanic ash that overlies colluvium derived from weakly weathered granitic

rocks. Slope gradients range from 35 to 50 percent. Soils on this landform

are deep and well drained. These soils are weakly developed and consist of

gravelly loam or silt loam surface layers and very gravelly or very cobbly

sandy loam to sand substrata. The dominant soils are classified as Andic

Cryochrepts and Dystric Cryochrepts. Rock outcrop occurs on less than 5

percent of this landscape component. The dominant potential natural vegetation

at mid elevations is grand fir and at higher elevations is subalpine fir and

subalpine fir-whitebark pine. This component represents 75 percent of this

unit.

Frost shattered ridge tops are formed in residuum and colluvium derived from

weakly weathered granitic rocks that has a thin veneer of volcanic ash loess at

the surface. Slope gradients range from 15 to 30 percent. Soils on this

landform are deep and well drained. These soils are poorly developed and

consist of gravelly loam or silt loam surface layers that overlie very gravelly

or very cobbly sandy loam substrata. The dominant soils are classified as

Andic Cryochrepts and Dystric Cryochrepts. Rock outcrop occurs on less than 5

percent of this landscape component. The dominant potential natural vegetation

at mid elevations is grand fir and at higher elevations is subalpine fir and

whitebark pine-subalpine fir series. This component represents 20 percent of

this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 110
LTA73-M332A

FROST SHATTERED MOUNTAIN RIDGE TOPS: VOLCANICS

Location: This unit is located in the Clearwater Mountains of north central

Idaho in the Salmon River Basin.

 Acreage by Section

 73-M332A 4,171

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a high elevation

mountain ridge landscape setting which is typically composed of frost shattered

ridge tops and mountain slopes. Parent materials are colluvium and residuum

underlain by weakly weathered volcanic rocks, typically basalt.

Accessory Characteristics: The primary soils are deep with loam textures that

have numerous rock fragments in the profile. The vegetation is coniferous

forest. Mean annual precipitation ranges from 89 to 102 centimeters (35 to 40

inches). The elevation range is 1650 to 2000 meters (5500 to 6700 feet). The

dominant slopes have gradients of 10 to 30 percent. This unit is slightly

dissected by streams, with the dominant stream pattern being parallel.

Wetlands are a minor component of this unit.

LTA Components: This landtype association consists of frost shattered mountain

ridge tops.

Frost shattered ridge tops are formed in residuum and colluvium derived from

weakly weathered basalt that has a thin veneer of volcanic ash loess at the

surface. Slope gradients range from 10 to 30 percent. Soils on this landform

are deep and well drained. These soils are moderately developed and consist of

gravelly loam or silt loam surface layers that overlie very gravelly or very

cobbly loam or clay loam substrata. The dominant soils are classified as

Andeptic Cryoboralfs. Rock outcrop occurs on less than 5 percent of this

landscape component. The dominant potential natural vegetation is grand fir

and subalpine fir series. This component represents 85 percent of this unit.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 111
LTA77-M332A

FROST SHATTERED MOUNTAIN RIDGE TOPS:

GNEISSES, QUARTZITES, AND SCHISTS

Location: This unit is located on ridges in north central and central Idaho in

the Clearwater, Snake, and Salmon River basins.

 Acreage by Section

 77-M332A 159,797

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is convex frost shattered

ridges and sideslopes Soils form in volcanic ash influenced loess and poorly

to moderately weathered gneiss, schist, and quartzite associated with the Idaho

Batholith. 

Accessory Characteristics: The primary soils are deep to very deep silt loams

and sandy loams. The vegetation is coniferous forest and openings dominated by

herbaceous plant communities. Mean annual precipitation ranges from 89 to 127

centimeters (35 to 50 inches). The elevation range is 160 to 2300 meters (5200

to 7500 feet). The dominant slopes have gradients of 20 to 50 percent. This

unit is poorly to moderately dissected by streams, with the dominant stream

pattern being dendritic. Wetlands are a significant component of this unit.

LTA Components: This landtype association consists of convex ridges and

sideslopes.

Frost shattered convex ridges and slopes are formed in volcanic ash influenced

loess and residuum of felsic metamorphic lithology. Soils on these landforms

are deep to very deep, poorly developed silt loams or loams with very gravelly

or cobbly loamy sand substrata. These soils are classified as Andic

Cryochrepts, Vitric Haplocryands and Vitric Fulvicryands. Rock outcrop is less

than 10 percent of the unit. The dominant potential natural vegetation at mid

elevations is grand fir, and at high elevations subalpine fir and whitebark

pine/subalpine fir series.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 112
LTA80-M332A

LOW RELIEF HILLS: METASEDIMENTARY (BELT)

Location: This unit is located in the Clearwater Mountains of Idaho in the

upper Lochsa River Basin.

 Acreage by Section

 80-M332A 1,243

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a mid elevation,

gentle to moderately sloping, mountain sideslope and ridge landscape setting,

which is composed of highly dissected mountain slopes and associated ridges

comprised deeply weathered residuum. Parent materials are surface volcani c ash 

overlying moderately to highly weathered quartzites, and siltites from

Precambrian metasedimentary bedrock.

Accessory Characteristics: The primary soils are deep silt loams and loams.

The vegetation is a mosaic of coniferous forest. Mean annual precipitation

ranges from 89 to 127 centimeters (35 to 50 inches). The elevation range of

this unit is 1068 to 1373 meters (3500 to 4500 feet). The dominant slopes have

gradients of 10 to 30 percent. This unit is highly dissected by streams, with

the stream pattern being strongly dendritic. Wetlands and moist seeps are a

common component of this unit.

LTA Components: This landtype association consists of low relief rolling

hills.

Low relief rolling hills with gentle to moderately steep slopes and are formed

in metasediments that consist of quartzites, siltites and inclusions of schists

overlain by Mazama volcanic ash. The slope gradients range from 10 to 40

percent. Soils on these landforms are deep, moderately to highly weathered and

medium textured. The major soils on the well drained sites are classified as

Vitric Hapludands, Typic Udivitrands, and Alfic Udivitrands. The dominant

potential natural vegetation on the well drained sites are westernredcedar and

grand fir. This component represents 90 percent of this unit.

Compiled by: Jim Mital, Clearwater National Forest and Jerry Niehoff, Idaho

Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 113
LTA81-M332A

LOW RELIEF HILLS: HIGHLY WEATHERED GRANITICS

Location: This unit is located in the Bitterroot Mountain Range of central

Idaho in the Selway River Basin.

 Acreage by Section

 81-M332A 139,140

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a moderately steep,

highly dissected mountain slope landscape setting which is typically composed

of dissected slopes, ridge tops, and noses of spur ridges. Parent materials

are colluvium and residuum underlain by highly weathered granitic bedrock.

Accessory Characteristics: The primary soils are shallow to deep with loamy

sand to sandy clay loam textures and have numerous rock fragments throughout

the profile. The vegetation is a mosaic of dry shrublands, grasslands, and

coniferous forest. Mean annual precipitation ranges from 64 to 102 cms (25 to

40 inches). The elevation range is 1097 to 1890 meters (3600 to 6200 feet).

The dominant slopes have gradients of 10 to 45 percent. This unit is highly

dissected by streams, with the dominant stream pattern being dendritic.

Wetlands are a minor component of this unit.

LTA Components: This landtype association consists of dissected mountain

slopes, and ridge tops.

Dissected mountain slopes are formed in colluvium derived from highly weathered

granitics. Slope gradients range from 25 to 45 percent. Soils on this

landform are moderately deep to deep and somewhat excessively to well drained.

These soils are poorly developed to well developed and consist of gravelly

sandy loam surface layer that overlies very gravelly to very cobbly loamy sand

or sandy clay loam substrata. The dominant soils are classified as Dystric

Cryochrepts, Typic Ustochrepts, and Typic Eutroboralfs. Rock outcrop occurs on

about 5 percent of this landscape component. The dominant potential natural

vegetation is Douglas-fir and subalpine fir series. This component represents

60 percent of this unit.

Ridge tops and associated noses of spur ridges are formed in residuum and

colluvium derived from highly weathered granitics. Slope gradients range from

10 to 25 percent. Soils on this landform are shallow to moderately deep and

somewhat excessively drained. These soils are poorly developed to well

developed and consist of gravelly or very gravelly sandy loam or loam surface

layers over very gravelly or very cobbly loamy sand or sandy clay loam

substrata. The dominant soils are classified as Lithic Argiborolls, Typic

Eutroboralfs, Typic Ustochrepts, and Dystric Cryochrepts. Rock outcrop occurs

on about 10 percent of this landscape component. The dominant potential

natural vegetation is Idaho fescue, Douglas-fir, and subalpine fir series.

This component represents 20 percent of this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 114
LTA82-M332A

LOW RELIEF HILLS: VOLCANICS

Location: This unit is located on isolated plateaus and broadridgetops above

granitic slopes and canyonlands in west central Idaho.

 Acreage by Section

 82-M332A 26,996

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is usually isolated plateaus

developed primarily in loess and moderately weathered residuum of Columbia

River basalt, in a landscape dominated by granitic lithology.

Accessory Characteristics: The primary soils are deep to very deep silt loams

and loams. The vegetation is dominantly coniferous forest. Mean annual

precipitation ranges from 76 to 127 centimeters (30 to 50 inches). The

elevation range is 1070 to 1800 meters (3500 to 5900 feet). The dominant

slopes have gradients of 5 to 30 percent. This unit is slightly to moderately

dissected by streams with the dominant stream pattern being dendritic. 

LTA Components: This landtype association consists of plateaus.

Plateaus are formed in loess and residuum of volcanic lithology. Slope

gradients range from 5 to 30 percent. Soils on these landforms are deep to

very deep, moderately developed silt loams with clay or silty clay substrata.

These soils are classified as Ultic Argixerolls and Andeptic Cryoboralfs. Rock

outcrop is less than 10 percent of the unit. The dominant potential natural

vegetation is Douglas-fir and grand fir series. Western red cedar is dominant

in the north part of the Clearwater basin.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 115
LTA83-M332A

LOW RELIEF HILLS: FINE TERTIARY SEDIMENTS

Location: This unit is located in west-central Idaho in the South Fork of the

Clearwater River Basin.

 Acreage by Section

 83-M332A 27,852

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a low to mid

elevation, gently to moderately sloping landscape setting which is typically

composed of low relief rolling hills and low mountains. Parent materials are

Mazama volcanic ash and wind-blown loess underlain by Tertiary alluvial

deposits.

Accessory Characteristics: The primary soils are deep to very deep with silt

loam surface textures and silt loam to silty clay subsurface textures. The

vegetation is a mosaic of coniferous forest. Mean annual precipitation ranges

from 64 to 102 cms. (25 to 40 inches). The elevation range is 762 to 1524

meters (2500 to 5000 feet). The dominant slopes have gradients of 5 to 30

percent. This unit is highly dissected by streams, with the dominant stream

pattern being dendritic. Wetlands are a minor component of this unit.

LTA Components: This landtype association consists of low relief rolling

hills.

Low relief rolling hills are formed in Tertiary alluvium overlain by Mazama 

volcanic ash and wind-blown loess. Slope gradients range from 5 to 30

percent. Soils on these landforms are deep to very deep, highly developed, and

consist of silt loam surface textures and silt loam to silty clay subsurface

textures. These soils are classified as Ultic Haploxeralfs, Typic

Eutroboralfs, and Andic Argixerolls. Rock outcrops are uncommon on this

landscape component. The dominant potential natural vegetation is grand fir

and Douglas-fir.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 116
LTA84-M332A

LOW RELIEF HILLS: HIGHLY WEATHERED SCHISTS

Location: This unit is located at middle elevations in north central Idaho in

the Clearwater River basin.

 Acreage by Section

 84-M332A 20,976

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is rolling uplands developed

in volcanic ash influenced loess and highly weathered residuum of Precambrian

schist.

Accessory Characteristics: The primary soils are very deep silt loams. The

vegetation is dominantly coniferous forest. Mean annual precipitation ranges

from 97 to 127 centimeters (38 to 50 inches). The elevation range is 1000 to

1800 meters (3000 to 5900 feet). The dominant slopes have gradients of 20 to

50 percent. This unit is highly dissected by streams, with the dominant stream

pattern being dendritic. Wetlands are a minor component of this map unit.

LTA Components: This landtype association consists of rolling hills.

Rolling hills are formed in volcanic ash influenced loess and schist

residuum. Soils on these landforms are very deep, moderately developed silt

loams with gravelly sandy loam substrata. These soils are classified a s Typic 

Udivitrands. Rock outcrop is less than 10 percent of the unit. The dominant

potential natural vegetation is western red cedar and grand fir, wit h Sitka 

alder communities in moist openings.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 117
LTA85-M332A

LOW RELIEF HILLS: MODERATELY WEATHERED GNEISSES,

QUARTZITES AND SCHISTS

Location: This unit is located at middle elevations in north central Idaho in

the Salmon River and Clearwater River basins.

 Acreage by Section

 85-M332A 180,023

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is rolling uplands developed

in volcanic ash influenced loess and moderately weathered residuum of gneiss,

schist, and quartzite associated with the Idaho batholith.

Accessory Characteristics: The primary soils are deep to very deep silt

loams. The vegetation is dominantly coniferous forest. Mean annual

precipitation ranges from 76 to 127 centimeters (30 to 50 inches). The

elevation range is 750 to 2000 meters (2500 to 6600 feet). The dominant slopes

have gradients of 20 to 50 percent. This unit is moderately to highly

dissected by streams, with the dominant stream pattern bein g dendritic.

Wetlands are a minor component of this map unit.

LTA Components: This landtype association consists of rolling hills.

Rolling hills are formed in volcanic ash influenced loess and quartzite,

gneiss, and schist residuum. Soils on these landforms are very deep,

moderately developed silt loams with gravelly sandy loam substrata. These

soils are classified as Andic Dystrochrepts. Rock outcrop is less than 10

percent of the unit. The dominant potential natural vegetation at mid

elevations is grand fir series, and at upper elevations subalpine fir series.

Western red cedar and alder communities in moist openings are common near the

north part of the Clearwater River basin.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 118
LTA90-M332A

MASS WASTED SLOPES: MIXED GEOLOGY

Location: This unit is located in west-central Idaho in the South Fork

Clearwater River and Selway River Basins.

 Acreage by Section

 90-M332A 29,413

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is mass wasted slopes. Parent

materials are can be of any lithology, but in this Section they are dominantly

volcanics (Columbia flood basalts) and gneisses and schists overlain with a

variable thickness of Mazama volcanic ash.

Accessory Characteristics: The primary soils are deep to very deep silt loams

to cobbly loams. The vegetation is a mosaic of coniferous forest. Mean annual

precipitation ranges from 51 to 102 cms (20 to 40 inches). The elevation range

is 610 to 1524 meters (2000 to 5000 feet). The dominant slopes have gradients

of 30 to 80 percent. This unit is moderately dissected by streams, with the

dominant stream pattern being parallel to dendritic. Wetlands are a minor

component of this unit, but moist seeps can be locally common.

LTA Components: This landtype association consists of mass wasted slopes.

Mass wasted slopes are formed in mixed Mazama volcanic ash overlying Columbia

River flood basalts and gneisses and schists. Slope gradients range from 30 to

80 percent. Soils on these landforms are deep to very deep, weakly to

moderately developed loams to cobbly loams, sometimes with a clayey substrata.

These soils are classified as Dystric Xerochrepts, Typic Dystrocrepts, and

Vitrandic Dystrochrepts. Rock outcrops occurs on less than 10 percent of this

unit. The dominant potential natural vegetation is ponderosa pine,

Douglas-fir, and grand fir.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 119
CHAPTER 6

LTA Descriptions

Section M332B Bitterroot Valley

This Section occurs in west central Montana. It is a portion of the Southwest

Montana Mountain and Valley area previously described. Forty eight LTAs were

mapped in this Section. See Appendix F for a complete list of LTAs and their

acreages. Map unit descriptions are preceded by the following illustrations:

 Figure 20: Map showing location of M332B within the Northern Region

 Figure 21: M332B landscape photograph

 Bitterroot National Forest

 Figure 22: Map showing distribution of LTAS within M332B

 Figure 23: Bar chart showing abundance of landform groups within M332B

 Figure 24: Bar chart showing abundance of geologic material groups within

 M332B

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 120
LTA10-M332Bd

VALLEYS: RECENT COARSE ALLUVIUM

Location: This LTA is located in the Sapphire Mountains, Flint Range, and the

Pintler Range on the Beaverhead-Deerlodge National Forest in the upper Clark

Fork River Basin in southwest Montana.

Acreage by Subsection

 10-M332Bd 27,680 

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a valley bottom landscape

setting, which is typically composed of floodplains and terraces. Parent

material is alluvium deposited over a variety of bedrock types.

Accessory Characteristics: The primary soils are deep with cobbly sandy and

loamy textures. The vegetation is a mosaic of grasslands, shrublands, and

coniferous forest. Mean annual precipitation ranges from 41 to 102 centimeters

(16 to 40 inches). The elevation range of this LTA is 1524 to 1829 meters

(5000 to 6000 feet). The dominant slopes have gradients of 0 to 20 percent.

This LTA is slightly dissected by streams, with the dominant stream pattern

being parallel. Wetlands are a major component of this LTA.

LTA Components: This landtype association consists of floodplains and

terraces.

Floodplains are formed in coarse alluvium. Slope gradients range from 0 to 10

percent. Soils on these landforms are deep, weakly developed, with cobbly

sandy and loamy textures. These soils are classified as Typic Cryaquepts and

Cryaquolls, and Typic and Oxyaquic Cryochrepts and Cryoborolls. Rock outcrop

does not occur on this landscape component. The dominant potential natural

vegetation is willow, sedge, spruce, and subalpine fir series. This component

represents 40 percent of this LTA.

Terraces are formed in coarse alluvium. Slope gradients range from 0 to 20

percent. Soils on these landforms are deep, weakly developed, with cobbly

sandy and loamy textures. These soils are classified as Typic Cryoboralfs,

Cryochrepts and Cryoborolls. Rock outcrop does not occur on this landscape

component. The dominant potential natural vegetation is Idaho fescue,

sagebrush, Douglas-fir, and subalpine fir series. This component represents 60

percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 121
LTA10-M332B

VALLEYS: RECENT COARSE ALLUVIUM

Location: This unit is located in the major valley bottoms of west-central

Montana and is in the Bitterroot, Blackfoot, and Upper Clark Fork River Basins.

 Acreage by Section

 10-M332B 174,283 (Section except M332Bd)

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a major valley

bottom landscape setting which is typically composed of floodplains, terraces,

and alluvial basins. Parent materials are recent alluvial deposits and older

outwash deposits.

Accessory Characteristics: The primary soils are very deep with coarse to

medium textures. The vegetation is a mosaic of dry coniferous forest, riparian

deciduous forest, and wet meadows. Mean annual precipitation ranges from 28 to

46 centimeters (11 to 18 inches). The elevation range is 975 to 1677 meters

(3200 to 5500 feet). The dominant slopes gradients are 0 to 6 percent. This

unit is moderately dissected by streams; the dominant stream pattern is

dendritic. Wetlands are a major component of this unit.

LTA Components: This landtype association consists of stream terraces,

floodplains, and alluvial basins.

Stream terraces are formed in mixed alluvium and glacial outwash. Slope

gradients range from 2 to 6 percent. Soils on this landform are very deep and

somewhat excessively to somewhat poorly drained. These soils are weakly

developed and consist of thin layer of loamy material over sand and gravel to

cobble-sized rocks. The dominant soils are classified as Fluvaquentic

Haploborolls and Typic Ustorthents. Rock outcrops do not occur in this

landscape component. The dominant potential natural vegetation is ponderosa

pine series. This component represents about 40 percent of this unit.

Floodplains are formed in extremely gravelly and cobbly, recent alluvium. Slope

gradients range from 1 to 3 percent. Soils on this landform are very deep and

poorly drained. These soils are weakly developed and consist mostly of

cobbles, gravels and sands. The dominant soils are classified as Typic

Fluvaquents. Rock outcrop does not occur on this landscape component. Areas

of cobbly to gravelly riverwash make up about 10 percent of this unit. The

dominant vegetation is a black cottonwood community type. The potential

natural vegetation is not certain. This component represents about 35 percent

of this unit.

Alluvial basins are formed in medium textured recent alluvium. Slope gradients

range from 0 to 2 percent. Soils on this landform are very deep and very

poorly drained. These soils are weakly developed and consist of several feet

of loamy and mucky alluvium over coarser sands and gravels. These soils are

classified as Fluvaquentic Endoaquolls. Rock outcrop does not occur on this

landform. The dominant potential natural vegetation is a complex of common

cattail and water sedge plant associations and Nebraska sedge community type.

Mountain alder community type occupies many areas of this component. This

component represents 25 percent of this unit.

Compiled by: Bob Spokas, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 122
LTA11-M332B

VALLEYS: LACUSTRINE DEPOSITS

Location: This unit is located primarily in the Upper Clark Fork River Basin

of northwestern Montana.

 Acreage by Section

 11-M332B 117,468

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a valley terrace

landscape setting, which is typically composed of Glacial Lake Missoula

lacustrine deposits on terraces and benches that have slightly undulating

surfaces. Parent materials consist of stratified lacustrine deposits of very

fine sand, silt and clay materials underlain by alluvial valley materials.

Accessory Characteristics: The primary soils are deep, layered, very fine

sand, silt and clay textured. Historically the vegetation was a continuous cover

of open grown coniferous forest. Today home developments and farmland cover many

of the acres of this LTA. Mean annual precipitation ranges from 33 to 51

centimeters (13 to 20 inches). The elevation range of this LTA is 616 to 1354

meters (2000 to 4400 feet). The dominant slopes have gradients of 0 to 25

percent except along incised draws. This unit is slightly dissected by

streams, where present, with the dominant stream pattern being dendritic.

These are very dry landscapes and typically do not contain wetland features.

LTA Components: This landtype association consists of lacustrine terraces.

Lacustrine terraces are formed in fine stratified materials. These terraces

have slope gradients ranging from 0 to 25 percent. Soils on these landforms

are deep, poorly developed and consist mostly of very fine sand, silt and

clay. The major soils are classified as Typic Eutroboralfs. Rock outcrop

occurs on less than 2 percent of this landscape component except as the

lacustrine material was deposited around scoured landscapes. The dominant

potential natural vegetation is the Douglas-fir series.

Compiled by: Skip Barndt, Lolo National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 123
LTA12-M332B

VALLEYS: OUTWASH AND OTHER OLDER COARSE ALLUVIUM

Location: This unit is located in the major river valleys of west-central

Montana which includes the Bitterroot, Blackfoot, and Upper Clark Fork River

basins.

 Acreage by Section

 

 12-M332B 292,138

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a major river valley

setting which is typically composed of coalescing glacial outwash fans and

stream terraces and of lesser amounts of associated glacial moraines. Parent

materials are coarse glacial outwash deposits that have high amounts of cobble,

gravel overlain by finer alluvium and coarse, bouldery glacial till.

Accessory Characteristics: The primary soils are very deep with coarse

textures and numerous rock fragments. The vegetation is a mosaic of coniferous

forest, savannahs, and dry grassland. Mean annual precipitation ranges from 28

to 51 centimeters (11 to 20 inches). The elevation range is 914 to 1585 meters

(3000 to 5200 feet). The dominant slopes have gradients of 2 to 30 percent.

This unit is slightly dissected by streams, with the dominant stream pattern

being parallel on fans and terraces and deranged on rolling moraines. Wetlands

and ponds are a minor component of this unit.

LTA Components: This landtype association consists of coalescing fans and

terraces, and rolling glacial moraines.

Coalescing fans and terraces are formed in coarse glacial outwash that is

overlain by a thin layer of medium textured alluvium. Slope gradients range

from 2 to 20 percent. Soils on this landform are very deep and somewhat

excessively drained. These soils are weakly developed and consist of dark,

gravelly loam about 15 inches thick overlying extremely cobbly sand outwash.

The dominant soils are classified as Typic Haploborolls and Aridic

Ustochrepts. Rock outcrop does not occur in this landscape component. The

dominant potential natural vegetation is a complex of ponderosa pine, rough

fescue and Douglas-fir series. This component represents 70 percent of this

unit.

Glacial moraines are formed in coarse, stony to bouldery glacial till. Slope

gradients range from 5 to 30 percent. Soils on this landform are very deep and

somewhat excessively drained. These soils are weakly developed and consist of

extremely bouldery sandy loam surface layers overlying extremely cobbly loamy

sand substrata. The dominant soils are classified as Typic Ustochrepts. Rock

outcrop occurs on less than 5 percent of this landscape component. The

dominant potential natural vegetation is Douglas-fir series. This component

represents 20 percent of this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 124
LTA14-M332B

VALLEYS: RECENT FINE ALLUVIUM

Location: This unit is located in the Sapphire Mountain Range of west-central

Montana and is in the Bitterroot River Basin.

 Acreage by Section

 14-M332B 33,479

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a major valley

bottom landscape setting which is typically composed of floodplains, stream

terraces, and alluvial basins. Parent materials are recent alluvial deposits.

Accessory Characteristics: The primary soils are very deep with moderately

fine to fine textures. The vegetation is a mosaic of dry coniferous forest,

riparian deciduous forest, and wet meadows. Mean annual precipitation ranges

from 46 to 61 centimeters (18 to 24 inches). The elevation range is 1341 to

1524 (4400 to 5000 feet). The dominant slopes have gradients of 0 to 8

percent. This unit is moderately dissected by streams, with the dominant

stream pattern being dendritic. Wetlands are a major component of this unit.

LTA Components: This landtype association consists of alluvial basins, stream

terraces, and floodplains.

Alluvial basins are formed in moderately fine textured recent alluvium.

Slope gradients range from 0 to 3 percent. Soils on this landform are very

deep and poorly or very poorly drained. These soils are weakly developed and

consist of several feet of moderately fine and mucky alluvium over coarser

sands and gravels. The dominant soils are classified as Cumulic Cryaquolls and

Histic Cryaquolls. Rock outcrop does not occur on this landscape component.

The dominant potential natural vegetation is a common cattail and water sedge

plant associations and Nebraska sedge community type. This component

represents about 35 percent of this unit.

Stream terraces are formed in mixed alluvium and glacial outwash. Slope

gradients range from 2 to 8 percent. Soils on this landform are very deep and

somewhat poorly to well drained. These soils are weakly developed and consist

of several feet of medium to moderately fine sediment over sands an d gravels. 

The dominant soils are classified as Oxyaquic Cryoborolls, and Cumulic

Cryoborolls. Rock outcrop does not occur on this component. The vegetation on

this component has all been converted to hay meadows and the potential natural

vegetation is uncertain. This component represents about 30 percent of this

unit.

Floodplains are formed in extremely gravelly and cobbly, recent alluvium.

Slope gradients range from 1 to 4 percent. Soils on this landform are very

deep and poorly drained. These soils are weakly developed and consist of

cobbles, gravels, and sands. The dominant soils are classified as Typic

Cryaquents. Areas of cobbly to gravelly riverwash also occur within this

component. Rock outcrop does not occur on this component. The dominant

vegetation is a black cottonwood community type. The potential natural

vegetation is uncertain. This component represents about 20 percent of this

unit.

Compiled by: Bob Spokas, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 125
LTA20-M332B

 BREAKS: METASEDIMENTARY (BELT)

Location: This unit is located in the Sapphire and Bitterroot Mountains of

west-central Montana and occurs in the Bitterroot, Blackfoot, and upper Clark

Fork River Basins.

 Acreage by Section

 20-M332B 360,304

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs on a very steep, deeply

eroded or faulted landscape setting which is typically composed of structural

or stream breaks. Parent material is colluvium and residuum derived from

metamorphosed Precambrian sedimentary bedrock and from small areas of volcanic

bedrock (mostly rhyolite and andesite).

Accessory Characteristics: The primary soils are shallow to very deep with

very gravelly to very cobbly medium textures. The vegetation is a mosaic of

dry to moist coniferous forest. Mean annual precipitation ranges from 46 to 102

centimeters (18 to 40 inches). The elevation range is 1219 to 2134 meters

(4000 to 7000 feet). The dominant slopes have gradients greater than 60

percent. This unit is moderately to highly dissected by streams, with the

dominant stream pattern being parallel. Wetlands are a minor component of this

unit. Wide valley bottoms occur at the base of this unit, but are generally

considered as map unit inclusions.

LTA Components: This landtype association consists of structural and stream

breaks:

These landforms are formed in colluvium and residuum. Slope gradients range

from 50 to 90 percent. Soils on these landforms are shallow to very deep and

well drained. These soils are weakly developed, and consist of very gravelly

sandy loam surfaces overlying extremely gravelly sandy loam substrata. The

dominant soils are classified as: Dystric and Lithic Cryochrepts, and Typic

and Lithic Ustochrepts. Rock outcrop and talus occupy about 15 percent of this

landscape. On cool, mesic sites the dominant potential natural vegetation is

subalpine fir series. On warmer, drier sites the dominant natural vegetation

is Douglas-fir series. Stream and/or structural breaklands represent about 85

percent of this unit.

Compiled by: Bob Spokas, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 126
LTA21-M332B

BREAKS: HIGHLY WEATHERED GRANITICS

Location: This unit is located in the southern end of the Bitterroot Mountains

and occurs in the Bitterroot River Basin of west-central Montana.

 Acreage by Section

 21-M332B 18,000

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs on a very steep, deeply

eroded landscape setting which is typically composed of stream breaks. Parent

material is colluvium and residuum derived from highly weathered granitic

bedrock.

Accessory Characteristics: The primary soils are shallow to deep, with very

gravelly to extremely gravelly coarse, sandy textures. The vegetation is a

mosaic of dry to moist coniferous forest. Mean annual precipitation ranges

from 41 to 102 centimeters (16 to 40 inches). The elevation range is 1280 to

2073 meters (4200 to 6800 feet). The dominant slopes have gradients greater

than 60 percent. This unit is moderately to highly dissected by streams, with

the dominant stream pattern being parallel. Talus and areas of rock outcrop

are major components of this map unit. Wetlands are a minor component of this

unit. Wide valley bottoms occur in this unit but are generally considered map

unit inclusions.

LTA Components: This landtype association consists of stream breaks.

These landforms formed in colluvium and residuum. Slope gradients range from

50 to 90 percent. Soils on these landforms are shallow to very deep and

somewhat excessively drained. These soils are weakly developed and consist of

very gravelly sandy loam surfaces overlying extremely gravelly loamy coarse

sand substrata. The dominant soils are classified as: Dystric and Lithic

Cryochrepts, and Typic and Lithic Ustochrepts. Rock outcrop and talus occupy

about 20 percent of this unit. On warmer, drier sites the dominant natural

vegetation is Douglas-fir series. On cool, mesic sites the dominant potential

natural vegetation is subalpine fir series. Stream breaklands represent about

85 percent of this unit.

Compiled by: Bob Spokas, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 127
LTA22-M332B

BREAKS: WEAKLY WEATHERED GRANITICS

Location: This unit is located in the lower Bitterroot Mountains which is in

the Upper Clark Fork River Basin of northwest Montana.

 Acreage by Section

 22-M332B 59,119

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs on mountain sideslope

landscape settings, which are composed of structural or stream breaks. Parent

materials are weakly weathered granitics. The landscape is dotted with

granitic tors, towers and rock outcrops due to the hardness of the material.

Accessory Characteristics: The primary soils are shallow extremely gravelly

sandy loams. The vegetation is a mosaic of coniferous forest and scree. Mean

annual precipitation ranges from 76 to 190 centimeters (30 to 75 inches). The

elevation range of this LTA is 985 to 2031 meters (3200 to 6600 feet). The

dominant slopes have gradients are greater than 60 percent. This unit is

moderately to highly dissected by streams, with the dominant stream pattern

being parallel. Talus, tors, towers, and rock outcrops are major components of

this map unit.

LTA Components: This landtype association consists of structural and stream

break components.

These landforms are developing on the steep mountain slopes adjacent to

drainage bottoms. The slope gradients range from 50 to 100 percent. Soils on

these landforms are shallow with minimal development. The major soils are

classified as Dystric Eutrochrepts and Andic Cryochrepts. Rock outcrops occupy

less than 15 to over 50 percent of the area. The dominant potential natural

vegetation is Douglas-fir and subalpine fir series.

Compiled by: Skip Barndt, Lolo National Forest.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 128
LTA24-M332B

BREAKS: VOLCANICS

Location: This unit is located in the Sapphire and Bitterroot Mountains and

occurs within the Bitterroot River Basin of west-central Montana.

 Acreage by Section

 24-M332B 14,377

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs on a very steep, deeply

eroded or faulted landscape setting which is typically composed of structural

and stream breaks. Parent material is colluvium and residuum derived from

volcanic bedrock (mostly rhyolite and andesite).

Accessory Characteristics: The primary soils are shallow to very deep with

very gravelly medium to moderately fine textures. The vegetation is a mosaic

of dry to moist coniferous forest. Mean annual precipitation ranges from 46 to

76 cms. (18 to 30 inches). The elevation range is 1219 to 2012 meters (4000 to

6600 feet). The dominant slopes have gradients greater than 60 percent. This

unit is moderately to highly dissected by streams, with the dominant stream

pattern being parallel. Combined, rock outcrop and talus are major components

of this map unit. Wetlands are a minor component of this unit. Wide valley

bottoms occur in this unit, but are generally considered only map unit

inclusions.

LTA Components: This map unit consists of structural and stream breaks.

These landforms are formed in colluvium and residuum. Slope gradients range

from 50 to 90 percent. Soils on these landforms are shallow to very deep and

well drained. These soils are weakly to moderately weathered, and consist of

gravelly loam surfaces overlying very gravelly clay loam or very gravelly loam

substrata. The dominant soils are classified as: Typic Ustochrepts, Typic

Eutroboralfs, Lithic Argiborolls, and Dystric and Lithic Cryochrepts. Rock

outcrop and talus occupy about 15 percent of this map unit. On cool, mesic

sites the dominant potential natural vegetation is subalpine fir series. On

warmer, drier sites the dominant natural vegetation is Douglas-fir series.

Stream and structural breaklands represent about 85 percent of this unit.

Compiled by: Bob Spokas, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 129
LTA25-M332B

BREAKS: SANDSTONES AND SHALES

Location: This LTA is located in the Flint Range on the Beaverhead-Deerlodge

National Forest in the upper Clark Fork River Basin in southwest Montana.

 Acreage by Section

 

 25-M332B 13,741

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of stream breaks. Parent materials are

residuum underlain by sandstone, shale and other mixed sedimentary bedrock.

Accessory Characteristics: The primary soils are shallow and moderately deep

with cobbly loamy textures. The vegetation is a mosaic of coniferous forest

and rock. Mean annual precipitation ranges from 41 to 51 centimeters (16 to 20

inches). The elevation range of this LTA is 1463 to 1982 meters (4800 to 6500

feet). The dominant slopes have gradients of 60 to 100 percent. This LTA is

moderately dissected by streams, with the dominant stream pattern being

parallel. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of stream breaks.

Stream breaks are formed in very steep, stream dissected sandstone, shale, and

other mixed sedimentary bedrock. Slope gradients range from 45 to 75 percent.

Soils on these landforms are shallow and moderately deep, weakly developed,

with cobbly loamy textures. These soils are classified as Lithic and Typic

Cryochrepts and Cryorthents, and includes some Lithic and Typic Cryoboralfs.

Rock outcrop occurs on 10 to 30 percent of this landscape component, depending

on rock type. The dominant potential natural vegetation is the Douglas-fir

series. This component represents 100 percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 130
LTA27-M332B

BREAKS: CARBONATES

Location: This LTA is located in the Flint Range on the Beaverhead-Deerlodge

National Forest in the upper Clark Fork River Basin in southwest Montana.

 Acreage by Section

 27-M332B 9,864

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of stream breaks. Parent materials are

residuum underlain by limestone bedrock.

Accessory Characteristics: The primary soils are shallow and moderately deep

with cobbly loamy textures. The vegetation is a mosaic of coniferous forest

and rock. Mean annual precipitation ranges from 41 to 51 centimeters (16 to 20

inches). The elevation range of this LTA is 1524 to 1982 meters (5000 to 6500

feet). The dominant slopes have gradients of 45 to 80 percent. This LTA is

moderately dissected by streams, with the dominant stream pattern being

trellis. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of stream breaks.

Stream breaks are formed in very steep, stream dissected limestone bedrock.

Slope gradients range from 45 to 75 percent. Soils on these landforms are

shallow and moderately deep, weakly developed, with cobbly loamy textures.

These soils are classified as Lithic and Typic Cryochrepts. Rock outcrop

occurs on about 15 percent of this landscape component. The dominant potential

natural vegetation is Douglas-fir. This component represents 100 percent of

this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 131
LTA29-M332B

BREAKS: QUARTZITES AND CALC-SILICATES

Location: This unit is located in the Sapphire Mountains and occurs in the

Bitterroot River Basin of west-central Montana.

 Acreage by Section

 29-M332B 5,637

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs on a very steep, deeply

eroded landscape setting which is typically composed of stream breaks. Parent

material is colluvium and residuum derived from weakly weathered quartzite and

calc-silicates of the Belt Supergroup.

Accessory Characteristics: The primary soils are shallow to deep with very

gravelly, very cobbly or extremely cobbly coarse to medium textures. The

vegetation is a mosaic of dry to moist coniferous forest. Mean annual

precipitation ranges from 46 to 89 cms. (18 to 35 inches). The elevation range

is 1219 to 2134 meters (4000 to 7000 feet). The dominant slopes have gradients

greater than 60 percent. This unit is moderately to highly dissected by

streams, with the dominant stream pattern being parallel. Rock outcrop, talus,

and scree combined, are major components of this map unit. Wetlands are a

minor component of this unit. Relatively wide valley bottoms occur in this

unit, but are generally considered only map unit inclusions.

LTA Components: This landtype association consists of stream breaks.

These landforms are formed in colluvium and residuum. Slope gradients range

from 50 to 90 percent. Soils on these landforms are shallow to deep and well

drained. These soils are weakly to moderately developed, and consist of very

cobbly loam surfaces overlying extremely cobbly fine sandy loam substrata. The

dominant soils are classified as: Typic and Lithic Ustochrepts, Typic

Eutroboralfs, Lithic Argiborolls, plus Dystric and Lithic Cryochrepts, Rock

outcrop, talus and scree occupy about 25 percent of this map unit. On warmer,

drier sites the dominant natural vegetation is Douglas -fir series. On cool,

mesic sites the dominant potential natural vegetation is subalpine fir series.

Stream breaklands represent about 85 percent of this unit.

Compiled by: Bob Spokas, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 132
LTA34-M332B

HIGH RELIEF MOUNTAIN SLOPES: VOLCANICS

Location: This LTA is located in the Blackfoot River drainage.

 Acreage by Section

 34-M332B 46,982

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountainous landscape

setting which is typically composed of steep mountain slopes. Parent material

is colluvium and residuum underlain by weakly weathered andesite and other

volcanic rocks. In some areas the parent material is influenced by a complex

of volcanic and metasedimentary Belt Series rocks.

Accessory Characteristics: The primary soils are moderately deep or deeper and

are medium to moderately fine textured. The vegetation is coniferous forest.

Mean annual precipitation ranges from 50 to 75 centimeters (20 to 30 inches).

The elevation range of this LTA is 1464 to 2135 meters (4800 to 7000 feet).

The dominant slopes have gradients of 25 to 60 percent. This LTA is moderately

dissected (moderately to widely spaced drainages) and deeply incised by streams

with the dominant stream pattern being dendritic. Small wetlands are sometimes

associated with slumpy areas.

LTA Components: This landtype association consists of high relief mountain

slopes.

High relief mountain slopes are mostly formed in andesite and other volcanic

rock. In some areas they are influenced by a complex of volcanic and

metasedimentary Belt Series rocks. Slope gradients range from 25 to 60

percent. Soils on these landforms are moderately deep to very deep, moderately

developed, and have very gravelly or gravelly loam, cobbly loam and stony loam

surfaces. Subsurface textures include very and extremely stony clay loam, very

and extremely cobbly loams, very gravelly clay loam and extremely gravelly

loam. These soils are classified as Typic Cryoboralfs, Typic Eutroboralfs, and

Typic Argiborolls. Rock outcrop occurs on less than 5 percent of this

landscape component. Small landslides are associated with basaltic and

andesitic dikes and sills or local ash/tuff deposits. The dominant potential

natural vegetation series are Douglas-fir and subalpine fir. This component

represents 100 percent of this LTA.

Compiled by: Larry Laing, Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 133
LTA35-M332B

WEAKLY GLACIATED MOUNTAIN SLOPES AND RIDGES:

CALC-SILICATES AND QUARTZITES

Location: This unit is located in the Bitterroot and Sapphire mountain ranges

of western Montana in the Bitterroot and Upper Clark Fork River Basins

 Acreage by Section

 35-M332B 27,909

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a high elevation

broad ridgetop position which is typically composed of weakly expressed

glaciated slopes and basins that were formed by ice -cap glaciers, minor valley

glaciers, and periglacial frost shattering. Parent materials are a complex of

frost shattered residuum and colluvium intermixed with glacial till derived

from Precambrian calc-silicate and quartzitic rocks.

Accessory Characteristics: The primary soils are shallow to deep, medium

textured soils with numerous rock fragments and have a volcanic ash surface

layer. The vegetation is a mosaic of coniferous forest, stunted wind-deformed

forest, and occasional small wet meadows. Mean annual precipitation ranges

from 102 to 140 centimeters (40 to 55 inches). The elevation range is 1951 to

2683 meters (6500 to 8800 feet). The dominant slopes have gradients of 20 to

55 percent. This unit is slightly dissected by streams, with the dominant

stream pattern being dendritic. Wetlands and ponds are a minor component of

this unit.

LTA Components: This landtype association consists of weakly developed glacial

cirques, and frost shattered mountain ridge tops.

Weakly developed glacial cirques are formed in residuum, colluvium, and till.

Slope gradients range from 20 to 55 percent. Soils on this landform are

shallow to deep and well drained. These soils are weakly developed and consist

of extremely bouldery loam volcanic ash surface layers overlying very stony

sandy loam substrata. The dominant soils are classified as Lithic and Andic

Cryochrepts. Rock outcrop occurs in about 10 percent of this landscape

component. The dominant potential natural vegetation is alpine larch-subalpine

fir, whitebark pine-subalpine fir, and subalpine fir series. This component

represents 65 percent of this unit.

Frost shattered mountain ridge tops are formed in residuum andcolluvium.

Slope gradients range from 20 to 50 percent. Soils on this landform are

shallow to deep and somewhat excessively drained. These soils are weakly

developed and consist of very stony loam volcanic ash surface layers overlying

very cobbly coarse sandy loam substrata. The dominant soils are classified as

Lithic and Andic Cryochrepts. Rock outcrop occurs on about 15 percent of this

landscape component. The dominant potential natural vegetation is whitebark

pine-subalpine fir, alpine larch-subalpine fir, and subalpine fir series. This

component represents 35 percent of this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 134
LTA37-M332B

HIGH RELIEF MOUNTAIN SLOPES: CARBONATES

Location: This LTA is located in the Alice/Nevada Mountains within the Clark

Fork basin.

 Acreage by Section

 37-M332B 6,635

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountainous landscape

setting which is typically composed of mountain slopes and narrow ridges.

Parent materials are colluvium and residuum underlain by limestones and

calcareous argillite.

Accessory Characteristics: The primary soils are moderately deep and shallow

with extremely limey and rocky subsurface layers. The vegetation is a mosaic

of coniferous forest with scattered grasslands and shrublands. Mean annual

precipitation ranges from 38 to 75 centimeters (15 to 30 inches). The

elevation range of this LTA is 1739 to 2288 meters (5700 to 7500 feet). The

dominant slopes have gradients of 40 to 60 percent. This LTA is moderately to

slightly (moderately to widely spaced) dissected and weakly incised by streams,

with the dominant stream patterns being subparallel and dendritic.

LTA Components: This landtype association consists of mountain slopes.

Mountain slopes are formed in limestone or calcareous argillite colluvium and

residuum. Slope gradients range from 40 to 60 percent. Soils on these

landforms are mostly moderately deep and shallow, weakly developed and are

loamy. These soils are classified as Typic and Lithic Ustochrepts, and Typic

and Lithic Cryochrepts. Rock outcrop occurs on about 15 percent of this

landscape component. The dominant potential natural vegetation is Douglas-fir

series. Subalpine fir series dominates on northerly aspects.

Compiled by: Larry Laing, Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 135
LTA40-M332B

STEEP GLACIATED MOUNTAIN SLOPES: METASEDIMENTARY (BELT)

Location: This unit is located in the Lower Bitterroot Garnet, Sapphire and

Swan Mountains of the Upper Clark Fork River basin of northwest Montana.

 Acreage by Section

 40-M332B 401,649

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a steep, alpine

glacial landscape setting. Parent materials are metasediments composed of

argillites, siltites and quartzites with alpine glacial till scattered

throughout; which is typically, medium textures.

Accessory Characteristics: The primary soils are shallow to moderately deep

moderately coarse to medium textured. The vegetation is a mosaic of coniferous

forest, avalanche chutes, and rock outcrops. Mean annual precipitation ranges

from 102 to 254 centimeters (40 to 100 inches). The elevation range of this

unit is 1785 to 2923 meters (5800 to 9500 feet). The dominant slopes have

gradients greater than 60 percent. This map unit is moderately to highly

dissected by streams, with the dominant stream pattern being parallel. Wet

sidehill areas and grassy parks are a major component of this unit.

LTA Components: This landtype association consists of steep, glaciated

mountain slopes, and narrow valley trains.

Steep, glaciated mountain slopes are formed in metasediments that consist of

argillites, siltites and quartzites. Glacial trough walls, headwalls and ridge

systems are formed in the underlying bedrock. The convex uplands and side

slopes have been strongly scoured and contain shallow soils. The lower slopes

have glacial till accumulations. These areas have slopes that range from 45

to 100 percent. Soils on the upper part of the landform are shallow to

moderately deep residuals and consist of rock and medium textured materials.

The lower portion of the landform has deep soils, formed in the glacial till

material. The major soils are classified as Cryandepts, Entic Cryandepts, and

Andic Cryochrepts. Rock outcrops occupy more than 40 percent of the area. The

dominant potential natural vegetation is subalpine fir. This landform

component makes up 80 percent of the unit.

The narrow valley train glacial till is developed on valley bottoms landforms.

Slope gradients range from 5 to 35 percent. Soils on these landforms are deep,

moderately developed and consist mostly of loamy glacial till. The major soils

are classified as Entic Cryandepts. The dominant potential natural vegetation

is subalpine fir. This landform component represents 20 percent of the unit.

Compiled by: Skip Barndt, Lolo National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 136
LTA41-M332B

STEEP GLACIATED MOUNTAIN SLOPES: GRANITICS

Location: This unit is located in the Bitterroot and Anaconda Mountain Ranges

of west-central Montana in the Bitterroot and Upper Clark Fork River Basins.

 Acreage by Section

 41-M332B 338,618

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs on steep and very steep

alpine glacial landscape settings. Parent material is colluvium, residuum, and

scattered alpine glacial till, derived from granitic sources.

Accessory Characteristics: The primary soils are shallow to deep, coarse

textured, and contain numerous rock fragments throughout the profile.

Additionally, avalanche chutes, rock outcrop, and rubble land are major

components to this map unit. The vegetation is a mosaic of closed to open

coniferous forest, and moist shrublands. Mean annual precipitation ranges from

46 to 254 cms. (18 to 100 inches). The elevation range is 1219 to 3110 meters

(4000 to 10200 feet). The dominant slopes have gradients of 15 to 100

percent. This unit is moderately to highly dissected by streams, with the

dominant stream pattern being parallel. Wetlands (wet side hills and avalanche

chutes), lakes, and ponds are major components of this unit.

LTA Components: This landtype association consists of glacial trough walls,

alpine ridges, and cirques (headwalls and basins).

Glacial trough walls were formed by alpine glacial scouring. After the

glaciers retreated the walls were further modified by landslides and avalanches

creating avalanche chutes. Slope gradients range from 50 to 100 percent and

slope shape is straight to concave. Soils on this landform are shallow to deep

and very poorly to somewhat excessively drained. These soils are weakly

developed, and consist of very cobbly loam surfaces overlying very cobbly loamy

sand or very cobbly sandy loam substrata. The dominant soils are classified

as: Lithic Cryochrepts, Andic Cryochrepts, Lithic Ustochrepts, and Typic

Ustochrepts. Typic Cryaquands occur extensively on northerly aspects in the

headwaters portion of these troughs. Rock outcrop, rubbleland, and avalanche

chutes occupy about 45 percent of this component. The most common potential

natural vegetation is subalpine fir, alpine larch-subalpine fir, and

Douglas-fir. Avalanche chutes have a sitka alder community type. The Typic

Cryaquands soils that occur in the headwater portions of trough walls support

a sitka alder habitat type. This landform component represents about 60

percent of this unit.

Cirque headwalls and basins were formed by alpine glacial erosion. Cirque

basins have slope gradients of 15 to 50 percent. Cirque headwalls have slope

gradients greater than 60 percent (approaching vertical). Soils on this

landform are shallow to very deep, and very poorly drained to well drained.

These soils are weakly developed and consist of very cobbly or extremely

bouldery silt loam volcanic ash surfaces over very cobbly or very bouldery

loamy sand substrata. The dominant soils on cirque headwalls are classified as

Andic Cryochrepts and Lithic Cryochrepts. Soils in cirque basins are

classified as Typic Cryandepts and Histic Cryaquepts. Rock outcrop, talus, and

scree occupy about 40 percent of this component. The dominant natural

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 137
vegetation is alpine larch-subalpine fir, whitebark pine-subalpine fir, and

subalpine fir on cirque headwalls and basins. The basins also contain Holm's

Rocky Mountain sedge, and beaked sedge. This landform represents about 25

percent of this unit.

Alpine ridges were formed by alpine glacial scouring and/or strong periglacial

frost shattering of exposed bedrock. Slope gradients range from 50 to 80

percent. Soils on this landform are shallow and somewhat excessively drained.

These soils are weakly developed and consist of very stony sandy loam surfaces

overlying extremely stony loamy sand substrata. Bedrock occurs at a depth of

less than 20 inches. The dominant soil is classified as Lithic Cryorthents;

however, only about 20 percent of this landform has a soil cover. Rock outcrop,

talus, and scree occupy about 80 percent of this component. The most common

potential natural vegetation is alpine larch -alpine fir, whitebark

pine-subalpine fir, and subalpine fir series. This landform represents about

15 percent of this unit.

Compiled by: Bob Spokas, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 138
 LTA43-M332Bd

LTA43-M332Eb

STEEP GLACIATED MOUNTAIN SLOPES: CARBONATES

Location: This LTA is located in the Anaconda and Flint Ranges, and Fleecer

Mountains on the Beaverhead-Deerlodge National Forest in the upper Clark Fork

River Basin of southwest Montana.

 Acreage by Subsection

 43-M332Bd 77,602

 43-M332Eb 2,698

LTA Setting and General Characteristics: 

Differentiating Characteristics: This LTA occurs in a glaciated mountain

landscape setting, which is typically composed of cirques, troughs, and

moraines. Parent materials are residuum underlain by limestone and glacial

moraines deposited on limestone and a variety of other bedrock types.

Accessory Characteristics: The primary soils are shallow to deep with cobbly

loamy textures. The vegetation is a mosaic of grasslands, shrublands, and

coniferous forest. Mean annual precipitation ranges from 51 to 127 centimeters

(20 to 50 inches). The elevation range of this LTA is 1829 to 3049 meters

(6000 to 10000 feet). The dominant slopes have gradients of 25 to 80 percent.

This LTA is moderately dissected by streams, with the dominant stream pattern

being parallel. Wetlands are a major component of this LTA.

LTA Components: This landtype association consists of cirques and troughs, and

moraines.

Cirques and troughs are formed in limestone bedrock. Slope gradients range

from 45 to 100 percent. Soils on these landforms are shallow and moderately

deep, weakly developed, with cobbly loamy textures. These soils are

classified as Typic and Lithic Cryorthents and Cryochrepts. Rock outcrop

occurs on 30 to 90 percent of this landscape component. The dominant potential

natural vegetation is Douglas-fir and subalpine fir series. This component

represents 40 percent of this LTA.

Moraines are composed of glacial deposits. Slope gradients range from 0 to 35

percent. Soils on these landforms are deep, moderately developed, with cobbly

loamy textures. These soils are classified as Typic Cryochrepts and

Cryoboralfs. Rock outcrop does not occur on this landscape component. The

dominant potential natural vegetation is sagebrush, Douglas -fir and subalpine

fir series. The dominant vegetation in wetlands is willows, sedge, and

subalpine fir. This component represents 60 percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 139
LTA44-M332B

STEEP GLACIATED MOUNTAIN SLOPES: SANDSTONES AND SHALES

Location: This LTA is located in the Flint Range on the Beaverhead-Deerlodge

National Forest in the upper Clark Fork River basin in southwest Montana.

 Acreage by Subsection

 44-M332B 18,787

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a glaciated mountain

landscape setting, which is typically composed of cirques, troughs, and

moraines. Parent materials are residuum underlain by sandstone and shale

bedrock, and moraines deposited on sandstone and shale and a variety of other

bedrock types.

Accessory Characteristics: The primary soils are shallow to deep with cobbly

loamy textures. The vegetation is coniferous forest. Mean annual

precipitation ranges from 46 to 127 centimeters (18 to 50 inches). The

elevation range of this LTA is 1768 to 2988 meters (5800 to 9800 feet). The

dominant slopes have gradients of 25 to 100 percent. This LTA is moderately

dissected by streams, with the dominant stream pattern being parallel. Wetlands

are a major component of this LTA.

LTA Components: This landtype association consists of cirques and troughs, and

moraines.

Cirques and troughs are formed in sandstone and shale bedrock. Slope gradients

range from 45 to 100 percent. Soils on these landforms are shallow and

moderately deep, weakly developed, and have cobbly loamy textures. These

soils are classified as Typic and Lithic Cryorthents and Cryochrepts. Rock

outcrop and scree occurs on 30-90 percent of this landscape component. The

dominant potential natural vegetation is subalpine fir series. This component

represents 60 percent of this LTA.

Moraines are composed of glacial deposits. Slope gradients range from 0 to 35

percent. Soils on these landforms are deep, moderately developed, with cobbly

loamy textures. These soils are classified as Typic Cryochrepts and

Cryoboralfs. Rock outcrop does not occur on this landscape component. The

dominant potential natural vegetation is Douglas-fir and subalpine fir series.

This component represents 40 percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 140
LTA45-M332B

LTA45-M332E

LTA45-M333D

WEAKLY GLACIATED MOUNTAIN SLOPES AND RIDGES: GRANITE

Location: This unit is located in the Bitterroot and Sapphire mountain ranges

of western Montana in the Bitterroot and Upper Clark Fork River Basins.

 Acreage by Section

 45-M332B 83,690

 45-M332E 2,112

 45-M333D 3,610

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a high elevation

broad ridgetop position which is typically composed of weakly expressed

glaciated slopes and basins that were formed by ice cap glaciers, minor valley

glaciers, and strong periglacial frost shattering. Parent materials are a

complex of frost shattered residuum and colluvium, intermixed with glacial till

derived from moderately weathered granite.

Accessory Characteristics: The primary soils are shallow to deep, coarse soils

with numerous rock fragments and have a volcanic ash surface layer. The

vegetation is a mosaic of coniferous forest, stunted wind-deformed forest, and

occasional small wet meadows. Mean annual precipitation ranges from 102 to 140

centimeters (40 to 55 inches). The elevation range is 2073 to 2743 meters

(6800 to 9000 feet). The dominant slopes have gradients of 20 to 55 percent.

This unit is slightly dissected by streams, with the dominant stream pattern

being dendritic. Wetlands and ponds are a minor component of this unit.

LTA Components: This landtype association consists of weakly developed glacial

cirques, and frost shattered mountain ridge tops.

Weakly developed glacial cirques are formed in residuum, colluvium, and till

derived from a variety of rock types. Slope gradients range from 20 to 55

percent. Soils on this landform are shallow to deep and somewhat excessively

drained. These soils are weakly developed and consist of extremely bouldery

loam volcanic ash surface layers overlying very stony loamy sand substrata.

The dominant soils are classified as Lithic and Andic Cryochrepts. Rock

outcrop occurs on about 10 percent of this landscape component. The dominant

potential natural vegetation is alpine larch -subalpine fir, whitebark

pine-subalpine fir, and subalpine fir series. This component represents 65

percent of this unit.

Frost shattered mountain ridge tops are formed in residuum and colluvium.

Slope gradients range from 20 to 50 percent. Soils on this landform are

shallow to deep and somewhat excessively drained. These soils are weakly

developed and consist of very stony loam volcanic ash surface layers overlying

very cobbly coarse sandy loam substrata. The dominant soils are classified as

Lithic and Andic Cryochrepts. Rock outcrop occurs on about 15 percent of this

landscape component. The dominant potential natural vegetation is whitebark

pine-subalpine fir, alpine larch-subalpine fir, and subalpine fir series. This

component represents 35 percent of this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 141
LTA50-M332B

GLACIATED MOUNTAIN SLOPES: METASEDIMENTARY (BELT)

Location: This unit is located in the lower Bitterroot, Garnet, Sapphire and

Swan Mountains of the Upper Clark Fork River basin of northwest Montana.

 Acreage by Section

 50-M332B 312,518

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs on gently to moderately

sloping glacial landscape settings. Parent materials are undifferentiated

glacial drift composed of argillites, siltites and quartzites. Small areas of

residual materials and rock outcrop are also included. These are medium

textured.

Accessory Characteristics: The primary soils are deep, moderately coarse to

medium textured. The vegetation is, typically, a mosaic of coniferous forest

and wetlands. Mean annual precipitation ranges from 64 to 127 centimeters (25

to 50 inches). The elevation range of this unit is 1077 to 1692 meters (3500

to 5500 feet). The dominant slopes have gradients less than 60 percent and,

typically, range from 10 to 35 percent. This map unit is slightly dissected by

streams, with the dominant stream pattern being dendritic. Wetlands, seeps,

bogs and riparian zones are common components of this unit.

LTA Components: This landtype association consists of gently to moderately

sloping glacial moraine.

Gently to moderately sloping glacial moraines are formed in the

undifferentiated belt materials, both till and outwash. The rolling plains are

dotted with wetlands, seeps, bogs and riparian zones. These areas have slopes

that range from 0 to less than 60 percent with moderately coarse to medium

textured materials. The major soils are classified as Andic Dystric

Eutrochrepts and Andic Cryochrepts. The dominant potential natural vegetation

is subalpine fir, grand fir, Douglas-fir and spruce.

Compiled by: Skip Barndt, Lolo National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 142
LTA51-M332B

GLACIATED MOUNTAIN SLOPES: GRANITIC

Location: This unit is located in the Bitterroot, Sapphire and Anaconda

Mountain Ranges of western Montana and occurs in the Bitteroot, Upper Clark

Fork, and the Blackfoot River Basins of western Montana.

 Acreage by Section

 51-M332B 197,817

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs on gently to moderately

sloping glacial landscape settings. Parent material is alpine glacial till,

alluvium, and residuum derived from granitic sources.

Accessory Characteristics: The primary soils are deep and very deep with

coarse to moderately coarse textures. Small inclusions of shallow soils, rock

outcrop, and rubble land can also be found within this unit. The vegetation is

a mosaic of moderately dry, moist, and wet coniferous forest. Mean annual

precipitation ranges from 41 to 102 centimeters (16 to 40 inches). The

elevation range is 1158 to 2134 meters (3800 to 7000 feet). Slope gradients

range from 1 to 60 percent. This unit is slightly to moderately dissected by

streams, with the dominant stream pattern being parallel. Wetlands, seeps,

bogs and riparian zones are major components of this unit.

LTA Components: This landtype association consists of glacial moraines, and

floodplains.

Glacial moraines were formed in alpine glacial till. Slope gradients range

from 8 to 60 percent and slope shape is convex. Soils on this landform are

shallow to deep, and moderately well to somewhat excessively drained. These

soils are weakly developed and consist of bouldery loam volcanic ash surface

layers overlying very cobbly loamy sand substrata. The dominant soils are

classified as: Andic Cryochrepts, Lithic Cryochrepts, Lithic Ustochrepts, and

Typic Ustochrepts. Rock outcrop and rubble land occupy about 10 percent of

this component. The dominant potential natural vegetation is subalpine fir and

Douglas-fir series. This landform component represents about 75 percent of

this unit.

Floodplains were formed in coarse alluvium. Slope gradients range from 1 to 8

percent. Soils on this landform are very deep and moderately well to very

poorly drained. These soils are very weakly develop and consist of cobbly loam 

surface layers overlying very gravelly loamy sand substrata. The dominant

soils are classified as: Typic Cryaquents, Oxyaquic Cryofluvents, and Andic

Cryofluvents. Rock outcrop occurs on less than 5 percent of this component.

The dominant natural vegetation is western redcedar, grand fir, and subalpine

fir series. This landform represents about 25 percent of this unit.

Compiled by: Bob Spokas, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 143
LTA53-M332B

LTA53-M333B

LTA53-M333C

GLACIATED MOUNTAIN SLOPES: SANDSTONES, SHALES, AND

CARBONATES

Location: This map unit is located in the Swan, Mission, Flathead, and

Whitefish mountain ranges of the Flathead, Clearwater, and Blackfoot River

basins in northwest Montana.

 Acreage by Section

 53-M332B 6,926

 53-M333C 100,613

 53-M333B 8,091

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in both valley bottom

and upland landscape settings, which are primarily composed of glacial moraine

landforms. Parent materials are continental or alpine glacial debris with or

without volcanic ash surface layers; underlain by Paleozoic and Mesozoic

sandstone, shale, and limestone bedrocks. In the North Fork of the Flathead

River areas of Tertiary siltstone are included in this map unit.

Accessory Characteristics: The primary soils are moderately deep to very deep,

with gravelly medium and moderately fine textures. The major vegetative cover

is a dense coniferous forest with occasional meadow openings. Mean annual

precipitation ranges from 51 to 178 centimeters (20 to 70 inches). The

elevation range is 1,036 to 2,316 meters (3400 to 7600 feet). The dominant

slopes range from 5 to 50 percent. This map unit is moderately to highly

dissected by streams, with the dominant stream pattern being dendritic.

Wetlands are a minor component of this unit.

LTA Components: This landtype association consists primarily of glacial

moraine landforms. Glacially scoured ridge tops are a minor component.

On the valley bottom landscape setting the glacial moraines occur on rolling

hummocky topography, with slopes that range from 5 to 30 percent slope. On the

upland landscape setting the glacial moraines occur on straight to slightly

concave slopes, with range from 20 to 55 percent in gradient. These glacial

moraines typically occur as the toe-slope associated with glacial troughwalls.

Soils on these landforms are moderately deep to very deep, and are moderate to

highly developed, with gravelly moderately-fine or fine textures. The major

soils are classified as Typic Eutrochrepts and Andeptic Cryoboralfs. Rock

outcrops occupy less than 15 percent of the area. The dominant potential

natural vegetation is Douglas-fir and subalpine fir.

A minor component of this map unit is glacially scoured ridge tops. Slope

gradients range from 5 to 20 percent. Soils on these landforms are shallow to

moderately deep, moderately developed, with gravelly medium textures. The

major soils are classified as Andic Cryochrepts. Rock outcrops occupy less

than 15 percent of the area. The dominant potential natural vegetation is

subalpine fir and Douglas-fir.This component represents 15 percent of this

map unit.

Compiled by: Dean Sirucek, Flathead National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 144
LTA57-M332B

GLACIATED MOUNTAIN SLOPES: SCHISTS

Location: This unit is located in the Bitterroot Mountain Range of western

Montana in the Bitteroot River basin.

 Acreage by Section

 57-M332B 9,352

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in the lower to middle

elevation portions of glaciated valleys. Parent material is alpine glacial

till, alluvium, and colluvium derived from schist.

Accessory Characteristics: The primary soils are deep and very deep with

coarse to moderately coarse textures. Inclusions of shallow soils, rock

outcrop, and rubble land occur within this unit. The vegetation is a mosaic of

moderately dry, moist, and wet coniferous forest. Mean annual precipitation

ranges from 41 to 102 centimeters (16 to 40 inches). The elevation range is

1280 to 2317 meters (4200 to 7600 feet). Slope gradients range from 5 to 60

percent. This unit is slightly to moderately dissected by streams, with the

dominant stream pattern being trellis. Wetlands, seeps, bogs and riparian

zones are major components of this unit.

LTA Components: This landtype association consists of lateral moraines and

footslopes, terraces and ground moraines, and floodplains.

Lateral moraines were formed in alpine glacial till. Footslopes consist of

colluvium from trough walls. Slope gradients range from 30 to 60 percent.

Soils on this landform are deep and moderately well to somewhat excessively

drained. These soils are weakly developed and consist of cobbly loam to sandy

loam surface layers overlying very cobbly sandy loam substrata. North-facing

slopes have a cobbly loam volcanic ash surface layer. The dominant soils are

classified as: Andic Cryochrepts, Dystric Cryochrepts, and Typic Ustochrepts.

Shallow soils, rock outcrop and rubble land occupy about 15 percent of this

component. The most common potential vegetation is the subalpine fir and

Douglas-fir series. This component represents about 60 percent of this unit.

Ground moraines formed in moderately coarse glacial till on valley floors.

Terraces formed in coarse outwash and alluvium and represent former

floodplains. Slope gradients range from 8 to 35 percent. Soils on this

landform are very deep and well drained to excessively drained. These soils

are weakly developed and consist of cobbly to bouldery loam surface layers

overlying very cobbly to very bouldery sandy loam or loamy sand substrata. The

dominant soils are classified as Andic Cryochrepts, Dystric Cryochrepts, and

Oxyaquic Cryofluvents. Rock outcrop occurs on about 10 percent of this

component. The dominant potential natural vegetation is the grand fir and

subalpine fir series. This component comprises about 25 percent of this unit.

Floodplains were formed in coarse alluvium. Slope gradients range from 5 to 10

percent. Soils on this landform are very deep and poorly to very poorly

drained. These soils are very weakly developed and consist of cobbly loam

surface layers overlying very gravelly to extremely cobbly loamy sand

substrata. The dominant soils are classified as: Typic Cryaquents, Typic

Cryaquepts, and Oxyaquic Cryofluvents. Rock outcrop occurs on less than 5

percent of this component. The dominant natural vegetation is the western

redcedar, grand fir, and subalpine fir series. Included in this component are

areas of silty wet soils in alluvial basins. These soils support alder,

willow, and sedge plant communities. Floodplains represents about 15 percent

of this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 145
LTA60-M332B

MOUNTAIN SLOPES AND RIDGES: METASEDIMENTARY (BELT)

Location: This unit is located in the Bitterroot, Sapphire, and Anaconda

mountain ranges of western Montana. It occurs in the Middle and Upper Clark

Fork River Basin which includes the Bitterroot, Blackfoot, Flint Creek, and

Clark Fork drainages.

 Acreage by Section

 60-M332B 767,352

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a nonglaciated steep

mountain slope setting, below the zone of strong frost shattering, which is

typically composed of moderately dissected mountain slopes, ridge tops, and

narrow valley bottoms. Parent materials are colluvium and residuum underlain

by Precambrian Belt rocks such as argillite, quartzite, and siltite.

Accessory Characteristics: The primary soils are shallow to deep,

medium-textured, and have numerous rocks fragments throughout the profile. The

vegetation is a mosaic of coniferous forest and native grasslands. Mean annual

precipitation ranges from 36 to 89 centimeters (14 to 35 inches). The

elevation range is 945 to 2073 meters (3100 to 6800 feet). The dominant slopes

have gradients of 10 to 55 percent. This unit is moderately dissected by

streams, with the dominant stream pattern being dendritic. Wetlands are a

minor component of this unit.

LTA Components: This landtype association consists of mountain slopes, and

ridge tops.

Mountain slopes are formed in colluvium and residuum. Slope gradients range

from 35 to 55 percent. Soils on this landform are shallow to deep and well

drained. Soils are weakly developed in areas underlain by the coarse-textured

rock types, such as quartzite, and having cooler forested habitat types. These

soils have gravelly fine sandy loam surface layers and extremely cobbly fine

sandy loam substrata. Soils that formed in material derived from fine-textured

rocks, such as argillite, and having warmer forested or grassland habitat types

are well developed. These soils have gravelly loam surface layers and very

cobbly sandy clay loam or clay loam substrata. The dominant soils are

classified as Typic and Lithic Ustochrepts, Dystric Cryochrepts, Typic

Eutroboralfs, and Lithic Argiborolls. Rock outcrop occurs on about 5 percent

of this landscape component. The dominant potential natural vegetation is

Douglas-fir, Idaho fescue and subalpine fir series. This component represents

75 percent of this unit.

Mountain ridge tops are formed in residuum. Slope gradients range from 10 to

35 percent. Soils on this landform are shallow to deep and well drained.

These soils are similar to those described above for the mountain slopes

landscape component. Rock outcrop occurs on about 20 percent of this landscape

component. The dominant potential natural vegetation is Douglas-fir and Idaho

fescue series. This component represents 20 percent of this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 146
LTA61-M332B

MOUNTAIN SLOPES AND RIDGES: HIGHLY WEATHERED GRANITICS

Location: This unit is located in the Bitterroot and Sapphire Mountains of

west-central Montana in the Bitterroot River Basin

 Acreage by Section

 61-M332B 92,627

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a non-glaciated,

dissected mountain slope setting, below the zone of strong frost shattering,

which is typically composed of steep mountain slopes, ridge tops, and narrow

valley bottoms. Parent materials are colluvium and residuum underlain by

highly weathered granitic bedrock.

Accessory Characteristics: The primary soils are deep, coarse, sandy soils

that have numerous rock fragments in the form of weathered gravels and

cobbles. The vegetation is a mosaic of coniferous forest and native

grasslands. Mean annual precipitation ranges from 41 to 102 centimeters (16 to

40 inches). The elevation range is 1158 to 2073 meters (3800 to 6800 feet).

The dominant slopes have gradients of 10 to 55 percent. This unit is highly

dissected by streams, with the dominant stream pattern being dendritic.

Wetlands are a minor component of this unit.

LTA Components: This landtype association consists of steep mountain slopes,

and ridge tops.

Steep mountain slopes are formed in colluvium. Slope gradients range from 30

to 55 percent. Soils on this landform are deep and excessively drained. These

soils are weakly developed and consist of gravelly sandy loam surface layers

overlying very gravelly or very cobbly loamy sand substrata. The dominant

soils are classified as Typic Ustochrepts and Dystric Cryochrepts. Rock

outcrop occurs on about 5 percent of this landscape component. The dominant

potential natural vegetation is Douglas-fir and subalpine fir series. This

component represents 80 percent of this unit.

Ridge tops formed in residuum and colluvium. Slope gradients range from 10 to

35 percent. Soils on this landform are shallow to deep and excessively

drained. These soils are weakly developed and consist of gravelly or very

gravelly sandy loam surface layers overlying very gravelly or very cobbly loamy

sand substrata. The dominant soils are classified as Lithic Ustochrepts, Typic

Ustochrepts, Dystric Cryochrepts, and Typic Haploborolls. Rock outcrop occurs

on about 10 percent of this landscape component. The dominant potential

natural vegetation is Douglas-fir and Idaho fescue series. This component

represents 15 percent of this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 147
LTA62-M332B

MOUNTAIN SLOPES AND RIDGES: WEAKLY WEATHERED GRANITICS

Location: This unit is located in the Bitterroot, Sapphire, and Anaconda

mountain ranges of western Montana and occurs in the Bitterroot, Blackfoot, and

Upper Clark Fork River basins.

 Acreage by Section

 62-M332B 152,086

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a non-glaciated steep

mountain slope landscape setting, below the zone of strong frost shattering,

and is typically composed of moderately dissected mountain slopes, ridge tops,

and minor amounts of narrow valley bottoms. Parent materials are colluvium and

residuum underlain by weakly weathered granitic bedrock.

Accessory Characteristics: The primary soils are shallow to deep, moderately

coarse-textured, and have numerous rock fragments throughout the profile. The

vegetation is a mosaic of coniferous forest, native grasslands, and at the

lowest elevations of the unit, dry shrublands. Mean annual precipitation

ranges from 41 to 89 centimeters (16 to 35 inches). The elevation range is

1220 to 2012 meters (4000 to 6600 feet). The dominant slopes have gradients of

10 to 55 percent. This unit is moderately dissected by streams, with the

dominant stream pattern being dendritic. Wetlands are a minor component of

this unit.

LTA Components: This landtype association consists of mountain slopes, and

ridge tops.

Mountain slopes are formed in colluvium and residuum. Slope gradients range

from 35 to 55 percent. Soils on this landform are shallow to deep and well

drained. These soils are weakly developed except that on warm, southeast to

west-facing slopes, soils are more developed. The weakly developed soils

consist of gravelly sandy loam surface layers overlying very cobbly sandy loam

substrata. The more developed soils have a gravelly sandy loam surface layer

that overlies very gravelly or very cobbly sandy clay loam or clay loam

substrata. The dominant soils are classified as Typic and Lithic Ustochrepts,

Dystric Cryochrepts, Typic Eutroboralfs, and Lithic Argiborolls. Rock outcrop

occurs on about 5 percent of this landscape component. The dominant potential

natural vegetation is Douglas-fir, Idaho fescue, bitterbrush, and subalpine fir

series. This component represents 75 percent of this unit.

Mountain ridge tops are formed in residuum. Slope gradients range from 10 to

35 percent. Soils on this landform are shallow to deep and well drained.

These soils are similar to those described above for the mountain slopes

landscape component. Rock outcrop occurs on about 20 percent of this landscape

component. The dominant potential natural vegetation is Douglas-fir,

bitterbrush, and Idaho fescue series. This component represents 20 percent of

this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 148
LTA63-M332B

MOUNTAIN SLOPES AND RIDGES: SCHISTS AND GNEISSESS

Location: This unit is located in the Bitterroot Mountain Range of

west-central Montana in the Bitterroot and Clark Fork River Basins.

 Acreage by Section

 

 63-M332B 5,513

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a non-glaciated steep

mountain slope landscape setting which is typically composed of steep mountain

slopes, ridge tops, and minor amounts of landslides and narrow valley bottoms.

These are mostly below the zone of strong frost shattering, but because of

limited acres, areas of high elevation frost shattered ridges were included in

the mapping of this unit. Parent materials are colluvium underlain by schist

and gneiss with high amounts of mica.

Accessory Characteristics: The primary soils are deep with sandy loam textures

and numerous rock fragments in the profile. The vegetation is a mosaic of

coniferous forest with minor amounts of dry, coniferous savannah. Mean annual

precipitation ranges from 64 to 178 centimeters (25 to 70 inches). The

elevation range is 1524 to 2439 meters (5000 to 8000 feet). The dominant

slopes have gradients of 25 to 55 percent. This unit is moderately dissected

by streams, with the dominant stream pattern being dendritic. Wetlands are a

minor component of this unit.

LTA Components: This landtype association consists of steep mountain slopes,

and moderately steep ridge tops.

Steep mountain slopes are formed in colluvium derived from schist and gneiss.

A thin layer of volcanic ash occurs at the surface on slopes with northerly

aspects. Slope gradients range from 40 to 55 percent. Soils on this landform

are deep and well drained. On southerly aspects, these soils are weakly

developed and consist of gravelly sandy loam surface layers overlying very

cobbly fine sandy loam substrata. On northerly aspects the surface layer is

silt loam derived from volcanic ash that overlies very gravelly to ver y cobbly 

loam or silt loam substrata. The dominant soils are classified as Dystric

Cryochrepts, Andic Cryochrepts, and Typic Ustochrepts. Rock outcrop occurs on

about 5 percent of this landscape component. The dominant potential natural

vegetation is subalpine fir and Douglas-fir series. This component represents

80 percent of this unit.

Mountain ridge tops and associated spur ridges are formed in residuum and

colluvium derived from schist or gneiss. Slope gradients range from 25 to 40

percent. Soils on this landform are shallow to moderately deep and well

drained. These soils are weakly developed and consist of gravelly sandy loam

surface layers that overlie very cobbly to very flaggy fine sandy loam

substrata. The dominant soils are classified as Lithic Argiborolls and Dystric

Cryochrepts. Rock outcrop occurs on about 10 percent of this landscape

component. The dominant potential natural vegetation is Douglas -fir and

subalpine fir series. This component represents 15 percent of this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 149
LTA64-M332Be

LTA64-M332Bk

LTA64-M332De

MOUNTAIN SLOPES AND RIDGES: VOLCANICS

Location: This LTA is located in the Sapphire and Boulder Mountains on the

Beaverhead-Deerlodge and Helena National Forests in the upper Clark Fork River

Basin in southwest Montana. It also occurs along the Continental Divide in the

Alice-Nevada Mountains.

 Acreage by Subsection

 64-M332Be 12,983

 64-M332Bk 7,098

 64-M332De 6,116

Map Unit Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a landscape setting which

is typically composed of mountain slopes and ridges. Parent materials are

residuum and colluvium underlain by rhyolite and tuff. Some ridges have ash

influenced soils.

Accessory Characteristics: The primary soils are shallow to moderately deep.

The primary soils have medium textured to moderately coarse textured surfaces

and moderately coarse to coarse textured subsurface layers. The vegetation is

a mosaic of coniferous forest and mountain grasslands. Mean annual

precipitation ranges from 46 to 75 centimeters (18 to 30 inches). The

elevation range of this LTA is 1677 to 2195 meters (5500 to 7200 feet). The

dominant slopes have gradients of 10 to 60 percent. This LTA is poorly to

moderately dissected by streams. Ridges are mostly undissected. Wetlands are a

minor component of this LTA.

Landscape Components: This map unit consists of mountain slopes and ridges.

Mountain slopes and ridges are formed in volcanic bedrock. Slope gradients

range from 10 to 60 percent. Soils on these landforms are shallow to

moderately deep and weakly to moderately developed. Surface textures range

from very gravelly sandy loam on steeper slopes to loams on volcanic ash

influenced ridges. Subsurface textures are often very cobbly coarse sandy loam

or extremely cobbly loamy sand. These soils are classified as Typic, Dystric,

Andic, and Lithic Cryochrepts, Typic and Lithic Cryoboralfs, and Argic and

Lithic Cryoborolls. Rock outcrop occurs on 5 to 15 percent of this landscape

component. The dominant potential natural vegetation is roughfescue,

Douglas-fir and subalpine fir series. This component represents 100 percent of

this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest, and Larry

Laing, Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 150
LTA64-M332B

MOUNTAIN SLOPES AND RIDGES: VOLCANICS

Location: This unit is located in the Bitterroot and Sapphire Mountain Ranges

of west-central Montana in the Bitterroot, Blackfoot, and Clark Fork River

Basins.

 Acreage by Section

 64-M332B 103,689 (Section except for M332Be and M332Bk)

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a non-glaciated steep

mountain slope landscape setting, below the zone of strong frost shattering,

which is typically composed of steep mountain slopes, moderately steep ridge

tops, and minor amounts of narrow valley bottoms. Parent materials are

colluvium and residuum underlain by volcanic andesites and rhyolites.

Accessory Characteristics: The primary soils are shallow to deep with loamy

textures and numerous rock fragments throughout the profile. The vegetation

is a mosaic of coniferous forest and dry native grasslands. Mean annual

precipitation ranges from 51 to 102 centimeters (20 to 40 inches). The

elevation range is 1524 to 2012 meters (5000 to 6600 feet). The dominant

slopes have gradients of 20 to 55 percent. This unit is moderately dissected

by streams, with the dominant stream pattern being dendritic. Wetlands are a

minor component of this unit.

LTA Components: This landtype association consists of steep mountain slopes,

and moderately steep ridge tops.

Steep mountain slopes are formed in colluvium derived from andesite or

rhyolite. Slope gradients range from 30 to 55 percent. Soils on this landform

are deep and well drained. These soils mostly are well developed and consist

of gravelly loam or sandy loam surface layers overlying very gravelly or very

cobbly sandy clay loam or clay loam substrata. Similar soils are less well

developed and generally have very cobbly sandy loam substrata. The dominant

soils are classified as Typic Cryoboralfs, Typic Eutroboralfs, Typic

Ustochrepts, and Lithic Argiborolls. Rock outcrop occurs on about 5 percent of

this landscape component. The dominant potential natural vegetation is

subalpine fir, Douglas-fir, and Idaho fescue series. This component represents

70 percent of this unit.

Mountain ridge tops and associated spur ridges are formed in residuum and

colluvium derived from andesite or rhyolite. Slope gradients range from 20 to

30 percent. Soils on this landform are mostly shallow to moderately deep and

well drained. These soils are well developed and consist of gravelly loam

surface layers overlying very gravelly or very cobbly sandy clay loam or clay

loam substrata. The dominant soils are classified as Lithic Argiborolls, Typic

Cryoboralfs, and Typic Eutroboralfs. Rock outcrop occurs on about 20 percent

of this landscape component. The dominant potential natural vegetation is

Idaho fescue, Douglas-fir and subalpine fir series. This component represents

20 percent of this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 151
LTA65-M332B

MOUNTAIN SLOPES AND RIDGES: SOFT SEDIMENTARY ROCKS

Location: This LTA is located in the Flint Range in the upper Clark Fork River

Basin in southwest Montana.

 Acreage by Section

 65-M332B 30,430

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of stream dissected mountain slopes.

Parent materials are residuum underlain by soft sedimentary rocks.

Accessory Characteristics: The primary soils are shallow and moderately deep

with cobbly loamy textures. The vegetation is a mosaic of coniferous forest

and mountain grasslands. Mean annual precipitation ranges from 41 to 76

centimeters (16 to 30 inches). The elevation range of this LTA is 1372 to 1829

meters (4500 to 6000 feet). The dominant slopes have gradients of 10 to 40

percent. This LTA is moderately dissected by streams, with the dominant stream

pattern being parallel. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of stream dissected

mountain slopes.

Stream dissected mountain slopes are formed in soft sedimentary rocks. Slope

gradients range from 10 to 50 percent. Soils on these landforms are shallow

and moderately deep, moderately developed, with cobbly loamy textures. These

soils are classified as Typic Cryochrepts and Cryoboralfs, and Typic and Argic

Cryoborolls. Rock outcrop occurs on about 5 percent of this landscape

component. The dominant potential natural vegetation is Idaho fescue and

Douglas-fir series. This component represents 100 percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 152
LTA66-M332B

MOUNTAIN SLOPES AND RIDGES: CARBONATES

Location: This LTA is located in the Flint Range on the Beaverhead-Deerlodge

National Forest in the upper Clark Fork River Basin in southwest Montana.

 Acreage by Section

 66-M332B 78,732

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of stream dissected mountain slopes.

Parent materials are residuum and colluvium underlain by limestone bedrock.

Accessory Characteristics: The primary soils are shallow and moderately deep

with cobbly loamy textures. The vegetation is a mosaic of coniferous forest

and mountain grasslands. Mean annual precipitation ranges from 41 to 64

centimeters (16 to 25 inches). The elevation range of this LTA is 1677 to 2439

meters (5500 to 8000 feet). The dominant slopes have gradients of 10 to 50

percent. This LTA is moderately dissected by streams, with the dominant stream

pattern being parallel. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of stream dissected

mountain slopes.

Stream dissected mountain slopes are formed in limestone bedrock. Slope

gradients range from 10 to 50 percent. Soils on these landforms are shallow

and moderately deep, moderately developed, with cobbly loamy textures. These

soils are classified as Argic and Typic Cryoborolls, and Lithic and Typic

Cryochrepts and Cryoboralfs. Rock outcrop occurs on about 10 percent of this

landscape component. The dominant potential natural vegetation is rough

fescue, Idaho fescue, Douglas-fir, and subalpine fir/grouse series. This

component represents 100 percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 153
LTA67-M332B

MOUNTAIN SLOPES AND RIDGES: CALC-SILICATES

Location: This unit is located in the Lower Bitterroot, Garnet, Sapphire and

Swan Mountains which is in the Upper Clark Fork River Basin of northwest

Montana.

 Acreage by Section

 67-M332B 72,462

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs on mountain sideslope

and ridge landscape settings, which are composed of structural mountain lands.

Parent materials are moderately weathered calc-silicate belt materials. Rock

outcrop is a common feature in this unit.

Accessory Characteristics: The primary soils are shallow to moderately deep

loams and sandy loams. The vegetation is a mosaic of coniferous forest and

parklands with small amounts of scree. Mean annual precipitation ranges from

51 to 152 centimeters (20 to 60 inches). The elevation range of this unit is

985 to 2031 meters (3200 to 6600 feet). The dominant slopes have gradients of

less than 60 percent. This unit is moderately to highly dissected by streams,

with the dominant stream pattern being parallel. Talus and rock outcrops are

major components of this map unit.

LTA Components: This landtype association consists of structural mountain

slopes and ridges.

These landforms are developing on moderately steep mountain slopes and ridges.

The slope gradients range from 35 to 60 percent. Soils on these landforms are

shallow to moderately deep and are medium textured. The major soils are

classified as Andic Dystric Eutrochrepts, Andic Cryochrepts, Typic

Eutroboralfs, Typic Ustochrepts, and Calcixerollic Xerochrepts. Rock outcrops

occupy less than 15 to over 50 percent of the area. The dominant potential

natural vegetation is Douglas-fir, western red cedar, grand fir and subalpine

fir series.

Compiled by: Skip Barndt, Lolo National Forest.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 154
LTA68-M332B

MOUNTAIN SLOPES AND RIDGES: SANDSTONES AND SHALES

Location: This LTA is located in the Flint Range on the Beaverhead-Deerlodge

National Forest in southwest Montana in the upper Clark Fork River Basin.

 Acreage by Section

 68-M332B 84,764

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of stream dissected mountain slopes.

Parent materials are residuum underlain by sandstone and shale bedrock.

Accessory Characteristics: The primary soils are shallow and moderately deep

with cobbly loamy textures. The vegetation is a mosaic of coniferous forest

and grasslands. Mean annual precipitation ranges from 41 to 76 centimeters (16

to 30 inches). The elevation range of this LTA is 1524 to 2134 meters (5000 to

7000 feet). The dominant slopes have gradients of 10 to 50 percent. This LTA

is moderately dissected by streams, with the dominant stream pattern being

parallel. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of stream dissected

mountain slopes.

Stream dissected mountain slopes are formed in sandstone and shale bedrock.

Slope gradients range from 10 to 50 percent. Soils on these landforms are

shallow and moderately deep, moderately developed, and have cobbly loamy

textures. These soils are classified as Typic and Lithic Cryochrepts and

Cryoboralfs; and Argic and Lithic Cryoborolls. Rock outcrop occurs on about 10

percent of this landscape component. The dominant potential natural vegetation

is rough fescue, Douglas-fir and subalpine fir series. This component

represents 100 percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 155
LTA70-M332B

FROST SHATTERED MOUNTAIN RIDGE TOPS: METASEDIMENTARY (BELT)

Location: This unit is located in the Bitterroot, Sapphire, and Anaconda

Mountain Ranges of western Montana and occurs in the Bitterroot and Upper Clark

Fork River Basins.

 Acreage by Section

 

 70-M332B 137,464

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a high elevation

mountain ridge landscape setting which is typically composed of frost shattered

ridge tops and mountain slopes. Parent materials are colluvium and residuum

underlain by Precambrian sedimentary Belt rocks.

Accessory Characteristics: The primary soils are deep with fine sandy loam

textures that have numerous rock fragments in the profile. The vegetation is a

fairly uniform cover of coniferous forest. Mean annual precipitation ranges

from 89 to 152 centimeters (35 to 60 inches). The elevation range is 2012 to

2500 meters (6600 to 8200 feet). The dominant slopes have gradients of 10 to

50 percent. This unit is slightly dissected by streams, with the dominant

stream pattern being parallel, but as mapped, areas of dendritic drainage

pattern also occur in about 30 percent of the unit. Wetlands are a minor

component of this unit.

LTA Components: This landtype association consists of frost shattered mountain

slopes, and ridge tops.

Frost shattered mountain slopes are formed in a thin layer of wind-deposited

volcanic ash that overlies colluvium derived from Belt rocks such as quartzite,

argillite, and siltite. Slope gradients range from 35 to 50 percent. Soils on

this landform are deep and well drained. These soils are weakly developed and

consist of gravelly or cobbly loam or silt loam surface layers and very cobbly

to extremely cobbly fine sandy loam substrata. The dominant soils are

classified as Andic Cryochrepts and Dystric Cryochrepts. Rock outcrop occurs

on about 10 percent of this landscape component. The dominant potential

natural vegetation is subalpine fir and whitebark pine-subalpine fir series.

This component represents 60 percent of this unit.

Frost shattered ridge tops are formed in residuum and colluvium from quartzite,

argillite, and siltite that has a thin veneer of volcanic ash loess at the

surface. Slope gradients range from 10 to 30 percent. Soils on this landform

are deep and well drained. These soils are poorly developed and consist of

cobbly to extremely cobbly loam or silt loam surface layers that overlie

extremely cobbly fine sandy loam substrata. The dominant soils are classified

as Andic Cryochrepts and Dystric Cryochrepts. Rock outcrop occurs on about 5

percent of this landscape component. The dominant potential natural vegetation

is subalpine fir and whitebark pine-subalpine fir series. This component

represents 30 percent of this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 156
LTA71-M332B

FROST SHATTERED MOUNTAIN RIDGE TOPS: HIGHLY WEATHERED GRANITICS

Location: This unit is located in the Bitterroot and Anaconda Mountain Ranges

of western Montana in the Bitterroot River Basin.

 Acreage by Section

 71-M332B 17,683

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a high elevation

mountain ridge landscape setting which is typically composed of frost shattered

ridge tops and mountain slopes. Parent materials are colluvium and residuum

underlain by highly weathered granitic rocks.

Accessory Characteristics: The primary soils are deep with loamy sand

textures that have numerous pea-sized and cobble-sized rock fragments in the

profile. The vegetation is a fairly uniform cover of coniferous forest. Mean

annual precipitation ranges from 76 to 152 centimeters (30 to 60 inches). The

elevation range is 1951 to 2439 meters (6400 to 8000 feet). The dominant

slopes have gradients of 10 to 40 percent. This unit is slightly dissected by

streams, with the dominant stream pattern being dendritic. Wetlands are a

minor component of this unit. Small areas of glaciation are included in this

map unit.

LTA Components: This landtype association consists of frost shattered mountain

slopes, and ridge tops.

Frost shattered mountain slopes are formed in a thin layer of wind-deposited

volcanic ash that overlies colluvium derived from highly weathered granitic

rocks. Slope gradients range from 30 to 40 percent. Soils on this landform

are deep and somewhat excessively drained. These soils are weakly developed

and consist of gravelly loam or silt loam surface layers and very gravelly

loamy-sand or coarse sandy loam substrata. The dominant soils are classified

as Andic Cryochrepts and Dystric Cryochrepts. Similar soils with

loamy-skeletal, mixed substrata occur in this component. Bedrock is highly

weathered granitics (grus). Rock outcrop occurs on less than 5 percent of this

landscape component. The dominant potential natural vegetation is subalpine

fir, and whitebark pine-subalpine fir series. This component represents 70

percent of this unit.

Frost shattered ridge tops are formed in residuum and colluvium derived from

highly weathered granitic rocks that has a thin veneer of volcanic ash loess at

the surface. Slope gradients range from 10 to 30 percent. Soils on this

landform are deep and somewhat excessively drained. These soils are poorly

developed and consist of gravelly loam or silt loam surface layers that overlie

very gravelly loamy sand or coarse sandy loam substrata. The dominant soils

are classified as Andic Cryochrepts and Dystric Cryochrepts. Areas of soils

having loamy-skeletal, mixed substrata also occur in this component. Bedrock

is highly weathered granitics. Rock outcrop occurs on less than 5 percent of

this landscape component. The dominant potential natural vegetation is

subalpine fir and whitebark pine-subalpine fir series. This component

represents 25 percent of this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 157
LTA72-M332B

FROST SHATTERED MOUNTAIN RIDGE TOPS: WEAKLY WEATHERED GRANITICS

Location: This unit is located in the Bitterroot, Sapphire, and Anaconda

Mountain Ranges of western Montana in the Bitterroot and Upper Clark Fork River

Basins.

 Acreage by Section

 72-M332B 94,500

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a high elevation

mountain ridge landscape setting which is typically composed of frost shattered

ridge tops and mountain slopes. Parent materials are colluvium and residuum

underlain by weakly weathered granitic rocks.

Accessory Characteristics: The primary soils are deep with sandy loam textures

that have numerous rock fragments in the profile. The vegetation is a fairly

uniform cover of coniferous forest. Mean annual precipitation ranges from 76

to 152 centimeters (30 to 60 inches). The elevation range is 1676 to 2500

meters (5500 to 8200 feet). The dominant slopes have gradients of 10 to 50

percent. This unit is slightly dissected by streams, with the dominant stream

pattern being dendritic. Wetlands are a minor component of this unit. Small

areas of glaciation are included in this map unit.

LTA Components: This landtype association consists of frost shattered mountain

slopes, and ridge tops.

Frost shattered mountain slopes are formed in a thin layer of wind-deposited

volcanic ash that overlies colluvium derived from weakly weathered granitic

rocks. Slope gradients range from 30 to 40 percent. Soils on this landform

are deep and well drained. These soils are weakly developed and consist of

gravelly loam or silt loam surface layers and very gravelly or very cobbly

sandy loam substrata. The dominant soils are classified as Andic Cryochrepts

and Dystric Cryochrepts. Rock outcrop occurs on less than 5 percent of this

landscape component. The dominant potential natural vegetation is subalpine

fir, and whitebark pine-subalpine fir series. This component represents 70

percent of this unit.

Frost shattered ridge tops are formed in residuum and colluvium derived from

weakly weathered granitic rocks that has a thin veneer of volcanic ash loess at

the surface. Slope gradients range from 10 to 30 percent. Soils on this

landform are deep and well drained. These soils are poorly developed and

consist of gravelly loam or silt loam surface layers that overlie very gravelly

or very cobbly sandy loam substrata. The dominant soils are classified as

Andic Cryochrepts and Dystric Cryochrepts. Rock outcrop occurs on less than 5

percent of this landscape component. The dominant potential natural vegetation

is subalpine fir, and whitebark pine-subalpine fir plant associations. This

component represents 25 percent of this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 158
LTA73-M332B

FROST SHATTERED MOUNTAIN RIDGE TOPS: VOLCANICS

Location: This unit is located in the Bitterroot Mountain Range of western

Montana in the Bitterroot River Basin.

 Acreage by Section

 73-M332B 15,228

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a high elevation

mountain ridge landscape setting which is typically composed of frost shattered

ridge tops and mountain slopes. Parent materials are colluvium and residuum

underlain by weakly weathered volcanic rocks.

Accessory Characteristics: The primary soils are deep with sandy loam textures

that have numerous rock fragments in the profile. The vegetation is a fairly

uniform cover of coniferous forest. Mean annual precipitation ranges from 102

to 140 centimeters (40 to 55 inches). The elevation range is 1951 to 2439

meters (6400 to 8000 feet). The dominant slopes have gradients of 10 to 40

percent. This unit is slightly dissected by streams, with the dominant stream

pattern being parallel. Wetlands are a minor component of this unit.

LTA Components: This landtype association consists of frost shattered mountain

slopes, and ridge tops.

Frost shattered mountain slopes are formed in a thin layer of wind-deposited

volcanic ash that overlies colluvium derived from weakly weathered volcanic

rocks. Slope gradients range from 30 to 40 percent. Soils on this landform

are deep and well drained. These soils are weakly developed and consist of

gravelly loam or silt loam surface layers and very gravelly or very cobbly

sandy loam substrata. The dominant soils are classified as Andic Cryochrepts

and Dystric Cryochrepts. Rock outcrop occurs on less than 5 percent of this

landscape component. The dominant potential natural vegetation is subalpine

fir, and whitebark pine-subalpine fir series. This component represents 60

percent of this unit.

Frost shattered ridge tops are formed in residuum and colluvium derived from

weakly weathered volcanic rocks that has a thin veneer of volcanic ash loess at

the surface. Slope gradients range from 10 to 20 percent. Soils on this

landform are deep and well drained. These soils are poorly developed and

consist of gravelly to extremely cobbly loam or silt loam surface layers that

overlie very gravelly or very cobbly sandy loam substrata. The dominant soils

are classified as Andic Cryochrepts and Dystric Cryochrepts. Rock outcrop

occurs on less than 5 percent of this landscape component. The dominant

potential natural vegetation is subalpine fir, and whitebark pine-subalpine fir

series. This component represents 35 percent of this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 159
LTA74-M332B

FROST SHATTERED MOUNTAIN RIDGE TOPS: SANDSTONES AND SHALES

Location: This LTA is located in the Flint Range of the Beaverhead-Deerlodge

National Forest in the upper Clark Fork River Basin in southwest Montana.

 Acreage by Section

 74-M332B 6,428

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of frost shattered ridges and slopes.

Parent materials are residuum and colluvium underlain by sandstone shale, and

other mixed sedimentary bedrock.

Accessory Characteristics: The primary soils are shallow and moderately deep

with cobbly loamy textures. The vegetation is a mosaic of coniferous forest

and mountain grasslands. Mean annual precipitation ranges from 51 to 76

centimeters (20 to 30 inches). The elevation range of this LTA is 2134 to 2591

meters (7000 to 8500 feet). The dominant slopes have gradients of 20 to 60

percent. This LTA is slightly dissected by streams, with no apparent dominant

stream pattern. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of frost shattered ridges

and slopes.

Frost shattered ridges and slopes are formed in sandstone, shale and other

mixed sedimentary bedrock. Slope gradients range from 10 to 50 percent. Soils

on these landforms are shallow and moderately deep, weakly developed, with

cobbly loamy textures. These soils are classified as Lithic, Argic, and Typic

Cryoborolls, and Typic Cryochrepts and Cryorthents. Rock outcrop occurs on

about 5 percent of this landscape component and scree occupies an equal, and

sometimes larger, area. The dominant potential natural vegetation is rough

fescue and subalpine fir series. This component represents 100 percent of this

LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 160
LTA75-M332B

FROST SHATTERED MOUNTAIN RIDGE TOPS: CALC-SILICATES

Location: This unit is located in the Sapphire Mountain Range of west-central

Montana in the Bitterroot Basin.

 Acreage by Section

 75-M332B 15,252

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a high elevation

mountain ridge landscape setting which is typically composed of frost shattered

ridge tops and mountain slopes. Parent materials are colluvium and residuum

underlain by Precambrian calc-silicate (calcium-bearing) and quartzitic rocks.

Accessory Characteristics: The primary soils are deep with fine sandy loam to

clay loam textures that have numerous rock fragments in the profile. The

vegetation is a fairly uniform cover of coniferous forest. Mean annual

precipitation ranges from 89 to 127 centimeters (35 to 50 inches). The

elevation range is 1829 to 2439 meters (6000 to 8000 feet). The dominant

slopes have gradients of 20 to 50 percent. This unit is slightly dissected by

streams, with the dominant stream pattern being dendritic; but as mapped, areas

of parallel drainage pattern also occur in about 20 percent of the unit.

Wetlands are a minor component of this unit.

LTA Components: This landtype association consists of frost shattered mountain

slopes, and ridge tops.

Frost shattered mountain slopes are formed in a thin layer of wind-deposited

volcanic ash that overlies colluvium derived from calc-silicate and quartzitic

rocks. Slope gradients range from 35 to 50 percent. Soils on this landform

are deep and well drained. These soils are weakly developed and consist of

gravelly or cobbly loam or silt loam surface layers and very cobbly to

extremely cobbly fine sandy loam to clay loam substrata. The dominant soils

are classified as Andic Cryochrepts, Dystric Cryochrepts, and Typic

Cryoboralfs. Rock outcrop and scree occurs on about 5 percent of this

landscape component. The dominant potential natural vegetation is subalpine

fir and whitebark pine-subalpine fir series. This component represents 75

percent of this unit.

Frost shattered ridge tops are formed in residuum and colluvium from

calc-silicate and quartzitic rocks that has a thin veneer of volcanic ash loess

at the surface. Slope gradients range from 20 to 30 percent. Soils on this

landform are deep and well drained. These soils are poorly developed and

consist of cobbly to extremely cobbly loam or silt loam surface layers that

overlie very cobbly fine sandy loam to clay loam substrata. The dominant soils

are classified as Andic Cryochrepts, Dystric Cryochrepts, and Typic

Cryoboralfs. Rock outcrop and scree occurs on about 5 percent of this

landscape component. The dominant potential natural vegetation is subalpine

fir and whitebark pine-subalpine fir series. This component represents 20

percent of this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 161
LTA80-M332B

LOW RELIEF HILLS: METASEDIMENTARY (BELT)

Location: This unit is located in the Philipsburg valley in the vicinity of the

Beaverhead National Forest in southwest Montana. It occurs in the Upper Clark

Fork River basin in Subsection M33Be.

 Acreage by Section

 80-M332B 4,768

Map Unit Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a low relief mountain

setting and is typically composed of rolling hills. Parent materials are

weathered Belt residuum and colluvium.

Accessory Characteristics: The primary soils are deep and loamy. The

vegetation is a mosaic of coniferous forest. Mean annual precipitation

ranges from 46 to 64 centimeters (18 to 25 inches). The elevation range of

this unit is 1677 to 2134 meters (5500 to 7000 feet). The dominant slopes have

gradients of 10 to 30 percent. This unit is highly dissected by streams, with

the stream pattern being strongl dendritic.

Landscape Components: This map unit consists of low relief rolling hills.

Low relief rolling hills are formed in metasediments that consist of quartzites

and siltites. The slope gradients range from 10 to 30 percent. Soils on these

landforms are deep, moderately to highly weathered and medium textured. The

major soils on the well drained sites are classified as Typic and Lithic

Cryochrepts and Cryoboralfs. The dominant potential natural vegetation is

rough fescue, Douglas-fir and subalpine fir. This component represents 100

percent of this unit.

Compiled by: Dave Ruppert, Beaverhead-Deer Lodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 162
LTA81-M332B

LOW RELIEF HILLS: HIGHLY WEATHERED GRANITICS

Location: This unit is located in the Bitterroot and Sapphire Mountain Ranges

of west-central Montana in the Bitterroot River Basin.

 Acreage by Section

 81-M332B 105,939

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a moderately steep,

highly dissected mountain slope landscape setting which is typically composed

of dissected slopes, ridge tops, and noses of spur ridges. Parent materials

are colluvium and residuum underlain by highly weathered granitic bedrock.

Accessory Characteristics: The primary soils are shallow to deep with loamy

sand to sandy clay loam textures and have numerous rock fragments throughout

the profile. The vegetation is a mosaic of dry shrublands, grasslands, and

coniferous forest. Mean annual precipitation ranges from 41 to 127 centimeters

(16 to 50 inches). The elevation range is 1280 to 2348 meters (4200 to 7700

feet). The dominant slopes have gradients of 5 to 40 percent. This unit is

highly dissected by streams, with the dominant stream pattern being dendritic.

Wetlands are a minor component of this unit.

LTA Components: This landtype association consists of dissected mountain

slopes, and ridge tops.

Dissected mountain slopes are formed in colluvium derived from highly weathered

granite. Slope gradients range from 30 to 40 percent. Soils on this landform

are moderately deep to deep and somewhat excessively to well drained. These

soils are poorly developed to well developed and consist of gravelly sandy loam

surface layer that overlies very gravelly to very cobbly loamy sand or sandy

clay loam substrata. The dominant soils are classified as Dystric Cryochrepts,

sandy-skeletal, mixed; Typic Ustochrepts, Typic Eutroboralfs, and Andic

Cryochrepts. Rock outcrop occurs on about 5 percent of this landscape

component. The dominant potential natural vegetation is Idaho fescue,

Douglas-fir and subalpine fir series. This component represents 60 percent of

this unit.

Ridge tops and associated noses of spur ridges are formed in residuum and

colluvium derived from highly weathered granite. Slope gradients range from 5

to 20 percent. Soils on this landform are shallow to moderately deep and well

drained. These soils are poorly developed to well developed and consist of

gravelly or very gravelly sandy loam or loam surface layers over very gravelly

or very cobbly sandy loam or sandy clay loam substrata. The dominant soils are

classified as Lithic Argiborolls, Lithic Eutroboralfs, Typic Ustochrepts, and

Dystric Cryochrepts. Rock outcrop occurs on about 10 percent of this landscape

component. The dominant potential natural vegetation is bitterbrush, Idaho

fescue, Douglas-fir and subalpine fir. This component represents 35 percent of

this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 163
LTA82-M332B

LOW RELIEF HILLS: VOLCANICS

Location: This unit is located in the Bitterroot Mountain Range of

west-central Montana in the Bitterroot River Basin.

 Acreage by Section

 82-M332B 10,401

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a moderately steep,

highly dissected mountain slope landscape setting which is typically composed

of dissected slopes, ridge tops, and noses of spur ridges. Parent materials

are colluvium and residuum underlain by weakly weathered volcanic bedrock.

Accessory Characteristics: The primary soils are shallow to deep with loam to

clay textures; rock content is highly variable throughout the profile. The

vegetation is a mosaic of coniferous forest with scattered patches of

coniferous savannah. Mean annual precipitation ranges from 64 to 102

centimeters (25 to 40 inches). The elevation range is 1463 to 1951 meters

(4800 to 6400 feet). The dominant slopes have gradients of 10 to 40 percent.

This unit is highly dissected by streams, with the dominant stream pattern

being dendritic. Wetlands are a minor component of this unit.

LTA Components: This landtype association consists of dissected mountain

slopes, and ridge tops.

Dissected mountain slopes are formed in colluvium derived from weakly weathered

rhyolitic and andesitic volcanic rocks. Slope gradients range from 20 to 40

percent. Soils on this landform are moderately deep to deep and well drained.

These soils are mostly well developed and consist of gravelly loam surface

layer that overlies very gravelly to very cobbly sandy clay loam to clay

substrata. The dominant soils are classified as Typic Eutroboralfs, Typic

Eutroboralfs, and Typic Ustochrepts. Rock outcrop occurs on less than 5

percent of this landscape component. The dominant potential natural vegetation

is Douglas-fir and subalpine fir series. This component represents 70 percent

of this unit.

Ridge tops and associated noses of spur ridges are formed in residuum and

colluvium derived from weakly weathered rhyolitic and andesitic volcanic

rocks. Slope gradients range from 10 to 30 percent. Soils on this landform

are shallow to moderately deep and well drained. These soils are well

developed and consist of gravelly or very gravelly sandy loam or loam surface

layers over very gravelly or very cobbly clay loam or sandy clay loam

substrata. The dominant soils are classified as Lithic Argiborolls, Lithic

Eutroboralfs, and Typic Ustochrepts. Rock outcrop occurs on less 5 percent of

this landscape component. The dominant potential natural vegetation is

Douglas-fir series. This component represents 25 percent of this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 164
LTA83-M332B

LOW RELIEF HILLS: FINE TERTIARY SEDIMENTS

Location: This unit is located in the Bitterroot and Sapphire Mountain Ranges

of western Montana. It occurs in the Bitterroot, Blackfoot, and Upper Clark

Fork River Basins. On the Helena National Forest it occurs in the Avon Valley

and the Nevada Creek and Sturgeon Creek drainages.

 Acreage by Section

 83-M332B 295,900

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a moderately steep,

highly dissected Tertiary-age valley fill landscape setting which is typically

composed of dissected slopes, ridge tops, and planar terrace treads. Parent

material is old, weathered alluvium derived from mixed sources.

Accessory Characteristics: The primary soils are deep with loam to clay loam

textures; rock content is highly variable throughout the profile. The

vegetation is a mosaic of native grassland and coniferous forest. Mean annual

precipitation ranges from 30 to 76 centimeters (12 to 30 inches). The

elevation range is 1067 to 1829 meters (3500 to 6000 feet). The dominant

slopes have gradients of 5 to 50 percent. This unit is highly dissected by

streams, with the dominant stream pattern being dendritic. Wetlands are a

minor component of this unit.

LTA Components: This landtype association consists of dissected terrace scarp

slopes, and ridge tops/terrace treads.

Dissected terrace slopes are formed in alluvium derived from granitic, Belt,

and volcanic rocks. Slope gradients range from 25 to 50 percent. Soils on

this landform are deep and well drained. These soils are mostly well developed

and consist of a cobbly loam surface layer that overlies very cobbly loam or

clay loam substrata. The dominant soils are classified as Aridic and Typic

Argiborolls, Typic Haploborolls, and Typic Eutroboralfs. Rock outcrop occurs

on less than 1 percent of this landscape component. The dominant potential

natural vegetation is rough fescue, big sagebrush, Idaho fescue and Douglas-fir

series. This component represents 50 percent of this unit.

Ridge tops and terrace treads are formed in alluvium derived from mixed sources

such as granitic, volcanic, and Belt rocks. Slope gradients range from 5 to 25

percent. Soils on this landform are deep and well or moderately well drained.

These soils are well developed and consist of cobbly or very cobbly loam

surface layers over very cobbly clay loam or loam substrata. The dominant

soils are classified as Aridic and Typic Argiborolls, Typic Eutroboralfs, and

Typic Eutroboralfs. Rock outcrop occurs on less 1 percent of this landscape

component. The dominant potential natural vegetation is rough fescue, big

sagebrush, and Douglas-fir series. This component represents 45 percent of

this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 165
LTA90-M332Bk

MASS WASTED SLOPES: MIXED GEOLOGY

Location: This LTA is scattered throughout the Alice-Nevada Mountains within

the Clark Fork basin.

 Acreage by Subsection

 90-M332Bk 4,177

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountainous landscape

setting, which is typically composed of mountain slopes and ridges. Parent

materials are old landslide deposits underlain by well weathered volcanic and

metasedimentary rock.

Accessory Characteristics: The primary soils are very deep and have clayey

subsoils. The vegetation is coniferous forest. Mean annual precipitation

ranges from 50 to 63 centimeters (20 to 25 inches). The elevation range of

this LTA is 1373 to 2012 meters (4500 to 6600 feet). The dominant slopes have

gradients of 10 to 40 percent. This LTA is moderately to highly dissected by

streams, with the dominant stream pattern being deranged. Wetlands are a major

component of this LTA.

LTA Components: This landtype association consists of landslides.

Landslides are formed in landslide deposits associated with well weathered

volcanic and metasedimentary bedrock. Slope gradients range from 10 to 40

percent. Soils on these landforms are very deep and well developed. They have

moderately fine textured surface layers and strong subsoil clay accumulations.

They typically have silty clay loam surface textures. Subsoils are silty clay

loam and silty clay with 15 to more than 35 percent rock (mostly gravel and

cobble). These soils are classified as Mollic Cryoboralfs. Inclusions of

Typic Cryaquolls are in bogs. At lower elevations Typic Eutroboralfs are more

typical. The dominant potential natural vegetation is subalpine fir and

Douglas-fir.

Compiled by: Larry Laing, Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 166
LTA90-M332Bd

MASS WASTED SLOPES: MIXED GEOLOGY

Location: This LTA is located in the Flint Range on the Beaverhead-Deerlodge

National Forest in the upper Clark Fork River basin in southwest Montana.

 Acreage by Subsection

 90-M332Bd 17,222

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of slumps and landflows. Parent materials

are slump and landflow deposits underlain by glacial moraine and Tertiary

sedimentary rocks.

Accessory Characteristics: The primary soils are deep, with loamy and clayey

textures. The vegetation is a mosaic of mountain meadows and coniferous

forest. Mean annual precipitation ranges from 41 to 76 centimeters (16 to 30

inches). The elevation range of this LTA is 1677 to 2287 meters (5500 to 7500

feet). The dominant slopes have gradients of 10 to 35 percent. This LTA is

highly dissected by streams, with the dominant stream pattern being parallel

and deranged. Wetlands are a major component of this LTA.

LTA Components: This landtype association consists of a complex of slumps and

landflows.

Slumps and landlows are formed in glacial moraine and Tertiary sedimentary

rocks. Slope gradients range from 10 to 45 percent. Soils on these landforms

are deep, moderately developed, with loamy and clayey textures. These soils

are classified as Typic Cryoboralfs and Typic and Oxyaquic Cryochrepts. Rock

outcrop occurs on less than 1 percent of this landscape component. The

dominant potential natural vegetation is Douglas-fir and subalpine fir series

with inclusions of hairgrass, sedge, and willow. This component represents 100

percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 167
LTA90-M332B

MASS WASTED SLOPES: MIXED GEOLOGY

Location: This unit is located in the Bitterroot Mountain Range of

west-central Montana and occurs in the Bitterroot River Basin.

 Acreage by Section

 90-M332B 7,375 (rest of Section except M332Bk and M332Bd)

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a steep mountain

slope landscape setting, which is typically composed of moist to wet mass

wasting and colluvial mountain slopes. Parent materials are landslide deposits

and colluvium underlain by micaceous schist bedrock.

Accessory Characteristics: The primary soils are deep, loamy soils with high

content of schist rocks. The vegetation is a mosaic of moist to wet coniferous

forest. Mean annual precipitation ranges from 64 to 140 centimeters (25 to 55

inches). The elevation range is 1585 to 2317 meters (5200 to 7600 feet). The

dominant slopes have gradients of 25 to 50 percent. This unit is moderately

dissected by streams, with the dominant stream pattern being incipient

dendritic. Wetlands and ponds are a major component of this unit.

LTA Components: This landtype association consists of steep mountain slopes,

and landslides.

Steep mountain slopes are formed in colluvium derived from micaceous schist.

Slope gradients range from 35 to 50 percent. Soils on this landform are deep

and well or moderately well drained. These soils are poorly developed and

consist of loam or silt loam surface layers overlying sandy loam or fine sandy

loam substrata. The dominant soils are classified as Andic Cryochrepts and

Dystric Cryochrepts. Rock outcrop occurs on less than 5 percent of this

landscape component. The dominant potential natural vegetation is subalpine

fir series. This component represents 70 percent of this unit.

Landslides are formed in unconsolidated landslide debris. Slope gradients

range from 25 to 40 percent. Soils on this landform are deep and very poorly

to somewhat poorly drained. These soils are poorly developed and consist of

gravelly loam or silt loam surface layers that overlie very cobbly fine sandy

loam or sandy loam substrata. The dominant soils are classified as Typic

Cryaquepts, Andic Cryochrepts, and Dystric Cryochrepts. Rock outcrop occurs on

about 5 percent of this landscape component. About 20% of this component is

comprised of soils having seasonally high water tables within a foot of the

surface. The dominant potential natural vegetation is subalpine fir series.

This component represents 20 percent of this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 168
LTA92-M332B

LTA92-M332E

LTA92-M332D

COLLUVIAL DEPOSITS: MIXED GEOLOGY

Location: This LTA is located throughout the Helena National Forest.

 Acreage by Section

 92-M332B 6,383

 92-M332E 3,557

 92-M332D 12,928

Map Unit Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountainous landscape

setting, which is typically composed of mountain slopes and ridges. Parent

materials are colluvial deposits, in basins and on toeslopes, typically

influenced by metasedimentary and volcanic rocks.

Accessory Characteristics: The primary soils are very deep and have loamy or

clayey subsoils. The vegetation is coniferous forest. Mean annual

precipitation ranges from 38 to 75 centimeters (15 to 30 inches). The

elevation range of this LTA is 1464 to 2135 meters (4800 to 7000 feet). The

dominant slopes have gradients of 10 to 50 percent. This LTA is highly

dissected (but weakly incised) by streams, with the dominant stream pattern

being parallel or subparallel. Wetlands are a major inclusion in this LTA.

Landscape Components: This map unit consists of one component:

Colluvial deposits are derived from metasedimentary and volcanic rock. Some

areas are also influenced by limestone colluvium. Slope gradients range from

10 to 50 percent. Soils on these landforms are very deep and weakly to well

developed. They have moderately fine textured surface layers and high subsoil

clay accumulations. They typically have very cobbly loam or cobbly silt loam

surface textures. Subsoils are very cobbly loam, clay loam or silty clay

loam. These soils are classified as Typic Cryochrepts, Typic Cryoboralfs, and

Argic Cryoborolls. Inclusions of Aquic Cryoborolls, Aquic Cryoboralfs and

Typic Cryaquepts are associated with seeps and springs. The dominant potential

natural vegetation series are subalpine fir, spruce, and Douglas-fir.

Compiled by: Larry Laing, Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 169
CHAPTER 7

LTA Descriptions

Section M332C Rocky Mountain Front

This Section occurs in northwest Montana. It is a portion of the Rocky

Mountain/Beartooth Front major geomorphic area previously described. Twenty

three LTAs were mapped in this Section. See Appendix F for a complete list of

LTAs and their acreages. Map unit descriptions are preceded by the following

illustrations.

Figure 25: Map showing location of M332C within the Northern Region

Figure 26: M332C landscape photograph

 Lewis Range, Glacier National Park

Figure 27: Map showing distribution of LTAS within M332C

Figure 28: Bar chart showing abundance of landform groups within M332C

Figure 29: Bar chart showing abundance of geologic material groups within

M332C

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 170
LTA10-M332C

LTA10-M332D

LTA10-331D

VALLEYS: RECENT COARSE ALLUVIUM

Location: This LTA is located in all mountain ranges of the Lewis and Clark

and Helena National Forests.

 Acreage by Section

 10-M332C 17,094

 10-M332D 86,889

 10-331D 982

LTA Setting and General Characteristics

Differentiating characteristics: This LTA occurs in a valley bottom landscape

setting which is usually composed of stream terraces, floodplains, and alluvial

fans. Parent materials are stratified alluvial deposits of sands, silts and

gravels.

Accessory characteristics: The primary soils are deep gravelly to extremely

gravelly sandy loams and loams. The vegetation is a mosaic of deciduous forest,

coniferous forest, well drained grassland and wet meadow. Mean annual

precipitation ranges from 38 to 75 centimeters (15 to 30 inches). The

elevation range of this LTA is 1159 to 1983 meters (3800 to 6500 feet). The

dominant slopes are 0 to 4 percent. This LTA by nature has very high stream

densities. Wetlands are an important component of this LTA.

LTA Components: This landtype association consists of floodplains, and stream

terraces and alluvial fans.

Floodplains and lower terraces are formed in a variety of stratified alluvium.

These floodplains have slope gradients that range from 0 to 2 percent. Soils on

these landforms are very deep, poorly developed, and consist mainly of sand,

gravel and cobble. Silts and clays are found to a lesser extent in oxbow

positions and areas historically occupied by beaver dams. The major soils are

highly variable and include Fluvents, Aquepts, Aquepts, Aquolls and Borolls.

The dominant potential natural vegetation series are Englemann spruce and

subalpine fir with inclusions of black cottonwood. This component represents

60 percent of this LTA.

Higher terraces and included fans are formed in alluvium. These terraces have

slope gradients that range from 0 to 4 percent. The alluvial fans often have

slope gradients of 8 to 25 percent. Soils on these landforms are deep, poorly

to well developed, and consist mainly of gravelly to extremely gravelly sandy

loams and loams. Sand, gravel and/or cobble layers or lenses are often

present. Areas of silt and clay are present in old oxbow and beaver dam

locations as well as glacial ice dams. The major soils are classified as

Haploborolls and Cryoborolls. The dominant potential natural vegetation series

are Douglas-fir, rough fescue, and big sagebrush. This component represents 40

percent of this LTA.

Compiled by: Richard Saunders, Lewis and Clark National Forest

Revised by Larry Laing, Helena and Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 171
LTA12-M332C

VALLEYS: OUTWASH DEPOSITS

Location: This unit is located along the Rocky Mountain Front in northwest

Montana on the Lewis and Clark National Forest.

 Acreage by Section

 12-M332C 40,434

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a major river valley

setting which is typically composed of glacial ground and lateral moraines with

coalescing glacial outwash fans and stream terraces. Parent materials range

from silty old lake bed deposits to gravelly and sandy glacial outwash.

Accessory Characteristics: The primary soils are very deep with coarse

textures and numerous rock fragments. The vegetation is principally lodgepole

pine forest. Mean annual precipitation ranges from 50 to 127 centimeters (20

to 50 inches). The elevation range is 1402 to 2073 meters (4600 to 6800

feet). The dominant slopes have gradients of 25 to 60 percent. This unit is

slightly dissected to highly dissected by low order streams, with the dominant

stream pattern being parallel. Wetlands and ponds are a minor component of

this unit.

LTA Components: This landtype association consists of ground moraines, and

steep lateral moraines.

Forested glacial ground moraines form on hilly rolling valley floors containing

glacial drift deposits and glacially scoured low relief bedrock hills. Slope

gradients range from 2 to 20 percent. Soils are developed in parent material

ranging from silty old lake beds to gravelly and sandy glacial outwash. Soils

on this landform are very deep and can be poorly drained in some areas. They

have loamy topsoils underlain by clayey subsoils. The dominant soils are

classified as Typic and Andic Cryoboralfs. Rock outcrop does not occur in this

landscape component. The dominant potential natural vegetation is spruce and

subalpine fir. This component represents 40 percent of this unit.

Forested steep lateral moraines are formed in clayey, slowly permeable glacial

drift. Slope gradient range from 25 to 60 percent. Soils on this landform are

very deep and poorly drained. These soils are weakly developed in thick layers

of silty wind deposited volcanic ash overlying clayey, slowly permeable glacial

drift. They typically have loamy topsoils and clayey subsoils. The dominant

soils are classified as Andic Cryochrepts in a clayey skeletal family. Perched

watertables develop above clayey subsoils during snowmelt. Rock outcrop is

rare. The dominant potential natural vegetation is subalpine fir. This

component represents 60 percent of this unit.

Compiled by: Robin Strathy, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 172
LTA20-M332C

BREAKS: METASEDIMENTARY (BELT)

Location: This unit is located in the southern part of the Rocky Mountain

Front in northwest Montana. It occurs mostly on the Lewis and Clark National

Forest.

 Acreage by Section

 20-M332C 13,659

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs on a very steep slopes

or faulted landscape setting which is typically composed of structural or

stream breaks. Parent material is colluvium and residuum derived from

metamorphosed Precambrian sedimentary bedrock; mostly quartzites and siltites

with some limestone. Some areas are overlain by silty volcanic ash. 

Accessory Characteristics: The primary soils develop in very gravelly or

stoney colluvium. They are typically deep, loamy soils. The vegetation is

mixed open forest (60 percent), bunchgrass parks (20 percent), and dense

lodgepole pine forest (20 percent). Mean annual precipitation ranges from 51

to 152 centimeters (20 to 60 inches), 50 percent of which falls as snow. The

elevation range is 1805 to 2460 meters (4000 to 7000 feet). The dominant

slopes have gradients from 55 to 80 percent. This unit is moderately to highly

dissected by streams, with the dominant stream pattern being subparallel.

Wetlands are a minor component of this unit.

LTA Components: This landtype association consists of structural and stream

breaks.

These landforms are formed in colluvium and residuum. Slope gradients range

from 55 to 70 percent. Soils on these landforms are deep and well drained.

These soils are weakly developed, and consist of loamy textures, and hav e silty 

topsoils over stoney colluvium or stoney loamy subsoils. The dominant soils

are Typic and Andic Cryochrepts, Typic Ustochrepts, and Lithic Cryandepts.

Rock outcrop and talus occupy about 10 to 50 percent of this landscape. On

cool, mesic sites the dominant potential natural vegetation is lodgepole pine

or mixed spruce and subalpine fir. On warmer, drier sites the dominant natural

vegetation is Douglas-fir at lower elevations, and subalpine fir at upper

elevations. Stream and structural breaks represent 100 percent of this unit.

Compiled by: Robin Strathy, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 173
LTA25-M332C

BREAKS: SANDSTONES AND SHALES

Location: This LTA occurs on the Lewis and Clark National Forest.

 Acreage by Section

 25-M332C 4,114

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of structural and stream breaks. Parent

materials are residuum underlain by sandstone, shale and other mixed

sedimentary bedrock.

Accessory Characteristics: The primary soils are shallow to moderately deep

with gravelly textures. The vegetation is a mosaic of coniferous forest and

rock. Mean annual precipitation ranges from 51 to 152 centimeters (20 to 60

inches). The elevation range of this LTA is 1676 to 2286 meters (5500 to 7500

feet). The dominant slopes have gradients of 55 to 70 percent. This LTA is

moderately dissected by streams, with the dominant stream pattern being sub

parallel to parallel. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of structural and stream

breaks.

Structural breaks are formed in colluvial materials from weakly weathered

sandstone, shale, and other mixed sedimentary bedrock. Slope gradients range

from 50 to 90 percent. Soils on these landforms are shallow to moderately deep

with gravelly textures. These soils are classified as Typic Cryochrepts. Rock

outcrop occurs on between 10 to 50 percent of this landscape component. The

dominant potential natural vegetation at lower elevations is Douglas-fir and at

higher elevations subalpine fir, and whitebark pine-subalpine fir. This

component makes up 70 percent of this unit.

Stream breaks are formed in very steep, stream dissected sandstone, shale, and

other mixed sedimentary bedrock. Slope gradients range from 45 to 75 percent.

Soils on these landforms are shallow to moderately deep, weakly developed, with

gravelly textures. These soils are classified as Typic Cryochrepts and Typic

Ustochrepts. Rock outcrop occurs on 10 to 30 percent of this landscape

component, depending on rock type. The dominant potential natural vegetation

is the Douglas-fir series at lower elevations and subalpine fir at higher

elevations. This component represents 30 percent of this LTA.

Compiled by: Robin Strathy, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 174
LTA27-M332C

LTA27-M333C

LTA27-331D

BREAKS: CARBONATES

Location: This LTA is located in the Rocky Mountain Front in northwest Montana

on the Lewis and Clark National Forest.

 Acreage by Section

 

 27-M332C 97,585

 27-M333C 461

 27-331D 149

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of structural breaks. Parent materials

are residuum underlain by limestone bedrock.

Accessory Characteristics: The primary soils are shallow and moderately deep

with loamy skeletal textures. The vegetation is a mosaic of coniferous forest

and rock. Mean annual precipitation ranges from 51 to 54 centimeters (20 to 25

inches). The elevation range of this LTA is 1968 to 2460 meters (6000 to 7500

feet). The dominant slopes have gradients of 60 to 80 percent. This LTA is

moderately to highly dissected by streams, with the dominant stream pattern

being subparallel. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of structural breaks.

Structural breaks are formed by thrust faulting along the eastern edge of the

overthrust belt, and are most dramatic in limestone bedrock. Slope gradients

range from 60 to 80 percent. Soils on these landforms are shallow to

moderately deep, weakly developed, overlie calcareous, very stony colluvium,

and have loamy skeletal textures. These soils are classified as Lithic and

Typic Ustochrepts and Typic Cryochrepts. Rock outcrop occurs on 15 to 50

percent of this landscape component. The dominant potential natural vegetation

is subalpine fir. This component represents 100 percent of this LTA.

Compiled by: Robin Strathy, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 175
LTA29-M332C

BREAKS: QUARTZITES AND CALC-SILICATES

Location: This LTA occurs on the Lewis and Clark National Forest.

 Acreage by Section

 29-M332C 585

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs on a very steep, deeply

eroded landscape setting which is typically composed of stream breaks. Parent

material is colluvium and residuum derived from weakly weathered quartzite and

calc-silicates of the Belt Supergroup.

Accessory Characteristics: The primary soils are shallow to deep with very

gravelly, very cobbly or extremely cobbly coarse to medium textures. The

vegetation is a mosaic of dry to moist coniferous forest. Mean annual

precipitation ranges from 46 to 89 cms. (18 to 35 inches). The elevation range

is 1676 to 2286 meters (5500 to 7500 feet). The dominant slopes have gradients

greater than 60 percent. This unit is moderately to highly dissected by

streams, with the dominant stream pattern being parallel. Rock outcrop, talus,

and scree combined, are major components of this map unit. Wetlands are a

minor component of this unit. Relatively wide valley bottoms occur in this

unit, but are generally considered only map unit inclusions.

LTA Components: This landtype association consists of stream breaks.

These landforms are formed in colluvium and residuum. Slope gradients range

from 50 to 90 percent. Soils on these landforms are shallow to deep and well

drained. These soils are weakly to moderately developed, and consist of very

cobbly loam surfaces overlying extremely cobbly fine sandy loam substrata. The

dominant soils are classified as Typic Cryochrepts. Rock outcrop, talus and

scree occupy about 25 percent of this map unit. On warmer, drier sites the

dominant natural vegetation is Douglas-fir series. On cool, mesic sites the

dominant potential natural vegetation is subalpine fir series. Stream breaks

represent about 85 percent of this unit.

Compiled by: Robin Strathy, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 176
LTA34-M332C

LTA34-M332D

LTA34-331D

HIGH RELIEF MOUNTAIN SLOPES: VOLCANICS

Location: This LTA is located in the Highwood, Little Belt, and Crazy

Mountains.

 Acreage by Section

 

 34-M332C 233

 34-M332D 15,602

 34-331D 6,622

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs on very steep mountain slopes

composed of convex ridges and shoulders in complex with smooth surfaces. Parent

material is sandstone, granite, and basalt.

Accessory Characteristics: The primary soil is shallow to moderately deep

very gravelly or stony loam or sandy loam. The vegetation is coniferous forest.

Mean annual precipitation ranges from 46 to 76 centimeters (18 to 30 inches)

The elevation range is 1830 to 2288 meters (6,000 to 7,500 feet). The dominant

slopes have gradients of greater than 60 percent. This LTA is slightly

dissected by streams with the dominant stream pattern being dendritic. Wetlands

are a minor component of this LTA.

LTA Components: This landtype association consists of very steep mountain

slopes.

These mountain slopes are formed in sandstone, granite and basalt. Slope

gradient is greater than 60 percent. Soil on this landform is shallow to

moderately deep, weakly developed and consists mainly of very gravelly or stony

colluvial material. These soils are classified as Typic Cryochrepts. Typically

10 to 25 percent of this landtype consists of rock outcrop. The dominant

potential vegetation is subalpine fir series with some scree. This component

represents the entirety of this LTA.

Compiled by: Rich Saunders, Lewis and Clark National Forest

Revised by Larry Laing, Helena/Lewis and Clark National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 177
LTA36-M332C

LTA36-M332D

LTA36-331D

HIGH RELIEF MOUNTAIN SLOPES: SANDSTONES AND SHALES

Location: This LTA is located throughout the Lewis and Clark National Forest

except in the Little Snowy Mtns.

 Acreage by Section

 36-M332C 13,447

 36-M332D 12,447

 36-331D 764

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs on very steep unglaciated

mountain slopes typically composed of convex ridges and shoulders in complex

with smooth surfaces. Parent materials are non-carbonate and sedimentary.

Accessory Characteristics: The primary soils are shallow to moderately deep

extremely gravelly loams. The vegetation is coniferous forest. Mean annual

precipitation ranges from 51 to 102 centimeters (20 to 40 inches). The

elevation range of this LTA is 1829 to 2743 meters (6000 to 9000 feet). The

dominant slopes have gradients of greater than 60 percent. This LTA is slightly

dissected by streams with the dominant stream pattern being radial. Wetlands

and lakes are virtually non-existent in this LTA.

LTA Components: This landtype association consists of convex ridges and

shoulders in complex with smooth surfaces. All of these landforms occur on

non-carbonate sedimentary rocks.

The convex ridges and shoulders have slope gradient of 25 to greater than 60

percent. Soils on these landforms are shallow to moderately deep, poorly

developed, and consist mainly of extremely gravelly sandy loam. The major

soils are classified as Typic Cryochrepts. Rock outcrop and talus occur on 75

percent of this unit. The dominant potential natural vegetation series is

subalpine fir-whitebark pine.

Compiled by: Richard Saunders, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 178
LTA37-M332C

HIGH RELIEF MOUNTAIN SLOPES: CARBONATES

Location: This LTA occurs in the southern part of the Rocky Mountain front in

northwest Montana on the Lewis and Clark National Forest.

 Acreage by Section

 37-M332C 4,666

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountainous landscape

setting which is typically composed of mountain slopes and narrow ridges.

Parent materials are colluvium and residuum underlain by limestones and

calcareous argillite.

Accessory Characteristics: The primary soils are moderately deep and shallow

with extremely lime and rocky subsurface layers. The vegetation is a mosaic

of coniferous forest with scattered grasslands and shrublands. Mean annual

precipitation ranges from 38 to 75 centimeters (15 to 30 inches). The

elevation range of this LTA is 1739 to 2592 meters (5700 to 8500 feet). The

dominant slopes have gradients of 40 to 60 percent. This LTA is moderately to

slightly (moderately to widely spaced) dissected and weakly incised by streams,

with the dominant stream patterns being subparallel and parallel.

LTA Components: This landtype association consists of mountain slopes.

Mountain slopes are formed in limestone or calcareous argillite colluvium and

residuum. Slope gradients range from 25 to 90 percent. Soils on these

landforms are mostly moderately deep and shallow, weakly developed and are

loamy. These soils are classified as Typic and Lithic Cryoborolfs, and Typic

and Andic Cryochrepts. Rock outcrop occurs on about 30 percent of this

landscape component. The dominant potential natural vegetation is Douglas-fir

series. Subalpine fir series dominates on northerly aspects.

Compiled by: Robin Strathy, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 179
LTA40-M332C

STEEP GLACIATED MOUNTAIN SLOPES: METASEDIMENTARY (BELT)

Location: This unit is located in the northern and southern part of the Rocky

Mountain Front in northwest Montana on the Lewis and Clark National Forest.

 Acreage by Section

 40-M332C 242,389

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a steep, alpine

glacial landscape setting. Parent materials are alpine glacial debris and

colluvium derived from metasediments composed of argillites, siltites and

quartzites.

Accessory Characteristics: The primary soils are shallow to moderately deep

and cobbly or gravelly to very stoney. The vegetation is a mosaic of

coniferous forest and shrubland associated with avalanche chutes. Mean annual

precipitation ranges from 51 to 254 centimeters (20 to 100 inches). The

elevation range of this unit is 1676 to 3048 meters (5500 to 10,000 feet). The

dominant slopes have gradients greater than 60 percent. This map unit is

moderately to highly dissected by streams, with the dominant stream pattern

being parallel. Wet areas are associated with cirques basins and are a minor

component of this unit.

LTA Components: This landtype association consists of steep glaciated valley

sideslopes, and peaks and alpine ridges.

Steep glaciated valley sideslopes, including glacial troughwalls, are formed

glacial tills on lower elevations and colluvium on higher elevation slopes.

Slopes range from 25 to 80 percent. Soils on the upper part of the landform

are shallow to moderately deep residuals and consist of rock and medium

textured materials. Soils on the lower slopes are moderately deep to deep with

cobbly medium textures. The major soils are classified as Typic and Andic

Cryochrepts. Rock outcrops occupy up to 40 percent of the area. The dominant

potential natural vegetation is subalpine fir. This landform component makes

up 80 percent of the unit.

Peaks and alpine ridges include steep to very steep peaks, glacial cirque

headwalls, and fault escarpment landforms. Slope gradients range from 60 to

100 percent. Rockland talus makes up more than 70 percent on this unit. Less

than 30 percent of the unit has a soil mantle. Soils develop in ver y stoney 

colluvial deposits and are deep and loamy. Vegetation is sparse, but the

dominant potential natural vegetation is subalpine fir. This landform

component represents 20 percent of the unit.

Compiled by: Robin Strathy, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 180
LTA43-M332C

LTA43-M332D

LTA43-M333C

LTA43-331D

STEEP GLACIATED MOUNTAIN SLOPES: CARBONATES

Location: This LTA is located mostly on the Rocky Mountain Front on the Lewis

and Clark National Forest.

 Acreage by Section

 43-M332C 158,089

 43-M332D 12,878

 43-M333C 235

 43-331D 625

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occupies high elevation landscapes

where alpine glaciation has occurred. It is typically occupied by fault

escarpments (especially in M332C), cirques, troughwalls, and ridges. The parent

material is limestone.

Accessory Characteristics: The primary soils are Lithic Cryorthents and

Cryochrepts, loamy-skeletal, mixed, cryic. The vegetation is coniferous

forest. Mean annual precipitation ranges from 76 to 127 centimeters (30 to 50

inches). The elevation range of this LTA is 1524 to 2438 meters (5000 to 8000

feet). The dominant slope gradients are 70 to 90 percent. This LTA is

moderately dissected by streams and the dominant drainage pattern is dendritic.

Wetlands, lakes, and ponds are a minor component of this LTA.

LTA Components: This landtype association consists of steep west facing slopes,

very steep glacial breaks, and rockland/scree on fault escarpments.

The steep west facing slopes are formed in limestone. These slopes have

gradient ranging from 40 to 60 percent. Soils on these landscapes are shallow,

poorly developed, and consist mainly of loam and flaggy gravel. These soils are

classified as Lithic Cryorthents. Rock outcrop occurs on less than 15 percent

of this landscape component. The dominant potential vegetation is open growing

wind deformed Douglas-fir, limber pine, and spruce on scree. This component

represents 30 percent of this LTA.

The very steep glacial breaks are formed in limestone. Slope gradients are

mainly greater than 60 percent. The soils of this landscape are deep, poorly

developed, and consist mainly of sandy-loam and gravel. These soils are

classified as Typic Cryochrepts. Rock outcrop and talus occur on seventy-five

percent of this landscape component. The dominant potential vegetation is

Douglas-fir series. This component represents 30 percent of this LTA.

The rockland/scree component of this LTA occur on fault escarpments in

limestone. Slopes are mainly greater than 60 percent. Soil on this landscape

consists of sandy loam, loamy sand, gravel, and cobble. These materials are

classified as scree. The dominant potential vegetation is subalpine fir, and

whitebark pine-subalpine fir series. This component represents 40 percent of

this LTA.

Compiled by: Richard Saunders and Robin Strathy, Lewis and Clark National

Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 181
LTA44-M332C

LTA44-M332D

LTA44-331D

 STEEP GLACIATED MOUNTAIN SLOPES: SANDSTONES AND SHALES

Location: This LTA is extensive throughout the Rocky Mountain Division on the

Lewis and Clark Forest and in the Elkhorn Mountains on the Beaverhead-Deerlodge

Forest.

 Acreage by Section

 44-M332C 101,583

 44-M332D 15,947

 44-331D 98

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occupies high elevation landscapes

where alpine glaciation has occurred. It is typically composed of glacial cirque

headwalls and rockland/scree on fault escarpments in Section M332C, and glacial

cirques in Section M332D. The parent material is sandstone and/or shale.

Accessory Characteristics: The primary soils are deep extremely cobbly sandy

loams and loams. The vegetation is coniferous forest. Mean annual precipitation

ranges from 63 to 88 centimeters (25 to 35 inches). The elevation range of

this LTA is 1500 to 2896 meters (5000 to 9000 feet). The dominant slopes have

gradients of 40 to greater than 60 percent. This association is moderately

dissected by streams, with the dominant stream pattern being parallel. Wetlands

are a minor component of this LTA.

LTA Components: This landtype association consists of glacial cirques,

rockland, and scree on fault escarpments.

Glacial cirques are formed in sandstone and shale. Soils on these landforms are

from very shallow to moderately deep, poorly developed, and consist mainly of

sandy loam and angular cobble. The major soils are classified as Typic, Andic

and Lithic Cryochrepts. Rock outcrop occurs on 5 to 15 percent of this

landscape component. The dominant potential natural vegetation series are

subalpine fir and whitebark pine. This component represents 60 percent of this

unit.

Rockland occurs on a variety of non-carbonate rocks. This component is a

miscellaneous landtype and is classified as scree. It does support some alpine

fir and whitebark pine. This component represents 25 percent of this LTA.

Compiled by: Richard Saunders and Robin Strathy, Lewis and Clark National

Forest, and Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 182
LTA50-M332C

GLACIATED MOUNTAIN SLOPES: METASEDIMENTARY (BELT)

Location: This unit occurs mostly in the northern part of the Rocky Mountain

Front in northwest Montana on the Lewis and Clark National Forest.

 Acreage by Section

 50-M332C 36,540

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs on gently to moderately

sloping glacial landscape settings. Parent materials are undifferentiated

glacial drift underlain by Proterozoic argillites, siltites, limestones and

quartzites. 

Accessory Characteristics: The primary soils are deep, with very gravelly

moderately coarse and medium textures. The vegetation is dense coniferous

forest with occasional meadow openings. Mean annual precipitation ranges from

36 to 203 centimeters (40 to 80 inches). The elevation range of this unit is

853 to 2286 meters (2800 to 7500 feet). The dominant slopes have gradients from

20 to 50 percent. This map unit is slightly dissected by streams, with the

dominant stream pattern being dendritic. Wetlands, seeps, bogs and riparian

zones are minor components of this unit.

LTA Components: This landtype association consists of gently to moderately

sloping glacial moraines.

Gently to moderately sloping glacial moraines are formed in the

undifferentiated Proterozoic materials. In valley bottoms, they form a rolling,

hummocky topography with slopes that range from 5 to 30 percent. On upland

landscape settings, glacial moraines occur on straight to slightly concave

slopes which range from 20 to 55 percent in gradient. Soils are moderately

deep to very deep, moderately to highly developed, with gravelly medium

textures. The major soils are classified as Andic Dystric Eutrochrepts and

Andic Cryochrepts. The dominant potential natural vegetation is subalpine fir,

grand fir, Douglas-fir and spruce.

Compiled by: Robin Strathy, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 183
LTA53-M332C

LTA53-M332D

GLACIATED MOUNTAIN SLOPES: SANDSTONES AND SHALES

Location: This LTA is located throughout the Lewis and Clark National Forest.

 Acreage by Section

 53-M332C 164,005

 53-M332D 10,191

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs on an alpine glacial till

landform which is typically composed of outwash benches, drift plastered trough

walls, and hilly valley bottoms. Parent materials are sandstones and shales.

Accessory Characteristics: The primary soils are deep, very cobbly loams. The

vegetation is subalpine forest. Mean annual precipitation ranges from 63 to 88

centimeters (25 to 35 inches). The elevation range of this LTA is 1524 to 1981

meters (5000 to 6500 feet). The dominant slopes have gradients of 10 to 40

percent. This landtype association is moderately dissected by streams with the

dominant stream pattern being parallel. Wetlands are a minor component of this

LTA.

LTA Components: This landtype association consists of clayey glacial drift

deposits, drift plastered trough walls, hilly valley bottoms, and hilly

glaciated valleys.

The clayey glacial drift deposits are formed mainly in sandstone and shale

material. Slope gradients range from 25 to 40 percent. The soils on these

landforms are deep, weakly developed, and loamy-skeletal. These soils are

classified as Typic Cryochrepts. Rock outcrop occurs on about 10 percent of

this landscape. The dominant potential natural vegetation is the subalpine fir

series.

The drift plastered trough walls are formed mainly in sandstone and shale

material. Slope gradients range from 25 to 40 percent. The soils on these

landforms are deep, weakly developed, and loamy-skeletal. These soils are

classified as Typic Cryochrepts. Rock outcrop occurs on about 10 percent of

this landscape. The dominant potential natural vegetation is the Douglas-fir

series.

The hilly valley bottoms are formed mainly in sandstone and shale. Slope

gradients range from 10 to 25 percent. The soils on these landforms are

moderately deep, weakly developed, and loamy-skeletal. These soils are

classified as Andic Cryochrepts. Rock outcrop occurs on about 15 percent of

this landscape. The dominant natural vegetation is the Douglas -fir series.

The hilly glaciated valleys are formed mainly in sandstone and shale. Slope

gradients range from 10 to 25 percent. The soils on these landforms are

moderately deep, weakly developed, clay loams with 35 to 50 percent gravel.

These soils are classified as Argic Cryoborolls. Rock outcrop occurs on less

than 5 percent of this LTA. The dominant natural vegetation is the rough

fescue series.

Compiled by: Richard Saunders, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 184
LTA60-M332C

MOUNTAIN SLOPES AND RIDGES: METASEDIMENTARY (BELT)

Location: This unit is located in the southern part of the Rocky Mountain

Front in northwest Montana on the Lewis and Clark National Forest.

 Acreage by Section

 60-M332C 57,511

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is composed of dissected

mountain slopes, glaciated mountain slopes, and glacially scoured ridge top

landforms. Parent materials are colluvium and residuum underlain by

Proterozoic metasedimentary bedrock, composed of argillites, siltites,

quartzites, and limestone.

Accessory Characteristics: The primary soils are shallow to moderately deep,

with very gravelly medium textures. The vegetation is a mosaic of coniferous

forest and mountain shrub/grass lands. Mean annual precipitation ranges from

51 to 152 centimeters (20 to 60 inches). The elevation range is 1524 to 2438

meters (5000 to 8000 feet). The dominant slopes have gradients of 25 to 60

percent. This unit is moderately to strongly dissected by streams, with the

dominant stream patterns being dendritic and subparallel. Wetlands are a minor

component of this unit.

LTA Components: This landtype association consists of dissected mountain

slopes, and glacially scoured ridge tops.

Dissected mountain slopes are formed in colluvium and residuum. Slope

gradients range from 25 to 60 percent. Soils on this landform are shallow to

deep and well drained. Soils are weakly to moderately developed with medium

textures. These soils generally have silty topsoils overlying stoney, loamy

subsoils. The dominant soils are classified as Andic Cryochrepts, and Typic or

Lithic Cryoborolls. Rock outcrop occupy less than 10 percent of this landscape

component. The dominant potential natural vegetation is Douglas-fir and

subalpine fir series. This component represents 60 percent of this unit.

Glacially scoured ridge tops feature ridge tops and ridge noses in exposed

bedrock. Slope gradients range from 25 to 50 percent. Soils on this landform

are comprised of thin layers of volcanic ash overlying stoney loamy materials

weathered from underlying rock. Dominant soils are classified as Andic

Cryochrepts. Rock outcrop occurs on about 50 percent of this landscape

component. The dominant potential natural vegetation is subalpine

fir-whitebark pine. This component represents 40 percent of this unit.

Compiled by: Robin Strathy, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 185
LTA66-M332C

LTA66-M333C

MOUNTAIN SLOPES AND RIDGES: CARBONATES

Location: This LTA is located primarily in the middle and southern part of the

Rocky Mountain front in Northwest Montana.

 Acreage by Section

 66-M332C 37,295

 66-M333C 164

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs on ridgetops, plateaus, steep

valley slopes, and benchy lower valley slopes. Parent materials are Paleozoic

limestones.

Accessory Characteristics: The primary soils are moderately deep,

loamy-skeletal loams, silt loams, and clay loams. The vegetation is a

coniferous forest. Mean annual precipitation ranges from 50 to 127 centimeters

(20 to 50 inches). The elevation range of this LTA ranges from 1524 to 2896

meters (5000 to 9500 feet). The dominant slopes have gradients of 10to greater

than 60 percent.

LTA Components: This landtype association consists of ridge-tops, and steep

valley sideslopes. All of these landforms are typically formed on limestone.

Ridge tops typically have slopes of 10 to 25 percent. Soils on these landforms

are moderately-deep, weakly developed, and consist mainly of loamy-skeletal

silt loams, loams, and clay loams. The major soils are classified as Perelgic

and Typic Cryoborolls. The major potential natural vegetation is rough

fescue. Rock outcrop occurs on less than 15 percent of this LTA. This

component represents 30 percent of this LTA.

Steep valley sideslopes are on slopes of 25 to 60 percent. Soils on these

landforms are moderately deep, moderately well developed, Andic Cryochrepts in

the loamy skeletal families. The major potential natural vegetation is

subalpine fir. Rock outcrop occurs on less than 15 percent of this LTA. This

component represents 70 percent of this LTA.

Compiled by: Robin Strathy, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 186
LTA68-M332C

LTA68-M332D

LTA68-331D

MOUNTAIN SLOPES AND RIDGES: SANDSTONES AND SHALES

Location: This LTA is located in the Little Belt Mountains and along the Rocky

Mountain Front on the Lewis and Clark National Forest, and in the Elkhorn

Mountains on the Beaverhead-Deerlodge Forest.

 Acreage by Section

 68-M332C 80,557

 68-M332D 336,224

 68-331D 8,549

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountain slope or ridge

setting which is typically composed of stream-dissected mountain slopes and

ridges. Parent materials are sandstone and shale.

Accessory Characteristics: The primary soils are moderately deep, skeletal

loamy sands and loams. The vegetation is a mosaic of subalpine fir and rough

fescue series. Mean annual precipitation ranges from 36 to 89 centimeters (14

to 35 inches). The elevation range is from 1524 to 2438 meters (5000 to 8000

feet). The slope gradient is from 10 to 60 percent. This LTA is moderately

dissected by streams with the dominant pattern being parallel. Wetlands are a

minor component.

LTA Components: This landtype association consists of low relief ridges and

slopes, and steep valley sideslopes.

The low relief ridges and slopes are formed in sandstone and shale. Slope

gradients are from 10 to 40 percent. Soils on these landforms are moderately

deep to deep, moderately well developed, extremely gravelly loams. These soils

are classified as Typic and Argic Cryoborolls. Rock outcrop occurs on about 5

percent of this landscape component. The dominant potential natural vegetation

series are rough fescue, Douglas-fir and subalpine fir. This component

represents 55 percent of this LTA.

The steep valley sideslopes are formed in sandstone and shale. Slope gradients

are from 40 to 60 percent. Soils on these landforms are loamy or

sandy-skeletal. These soils are classified mostly as Typic and Andic

Cryochrepts with some Cryoboralfs. Rock outcrop occurs on about 10 percent of

this landscape component. The dominant potential natural vegetation series is

subalpine fir. This component represents 30 percent of this LTA.

Compiled by: Richard Saunders and Robin Strathy, Lewis and Clark National

Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 187
LTA70-M332C

FROST SHATTERED MOUNTAIN RIDGE TOPS: METASEDIMENTARY (BELT)

Location: This unit is located in the northern and southern part of the Rocky

Mountain front in northwestern Montana. It occurs on the Lewis and Clark

National Forest.

 Acreage by Section

 

 70- M332C 10,583

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a high elevation

mountain ridge landscape setting which is typically composed of frost shattered

ridge tops and adjacent steep mountain slopes. Parent materials are colluvium

and residuum underlain by Precambrian metasedimentary Belt rocks.

Accessory Characteristics: The primary soils are deep with very gravelly

medium textures. The vegetation is a mosaic of coniferous forest and

bunchgrass parks. Mean annual precipitation ranges from 50 to 152 centimeters

(20 to 60 inches). The elevation range is 1676 to 2590 meters (5500 to 8500

feet). The dominant slopes have gradients of 10 to 80 percent. This unit is

undivided to slightly dissected by streams, with the dominant stream pattern

being dendritic. Wetlands are a minor component of this unit.

LTA Components: This landtype association consists of frost shattered steep

mountain slopes, and ridge tops.

Frost shattered steep mountain slopes are formed in a thin layer of

wind-deposited volcanic ash that overlies colluvium derived from Belt rocks

such as quartzite, argillite, and siltite. Slope gradients range from 35 to 80

percent. Soils on this landform are deep and well drained. These soils are

weakly developed and consist of gravelly or cobbly loam or silt loam surface

layers and stony loamy subsoils. The dominant soils are classified as Typic

and Andic Cryochrepts. Rock outcrop occurs on 10 to 50 percent of this

landscape component. The dominant potential natural vegetation is subalpine

fir and whitebark pine-subalpine fir series. This component represents 70

percent of this unit.

Frost shattered ridge tops are formed in residuum and colluvium from quartzite,

argillite, and siltite that has a thin veneer of volcanic ash loess at the

surface. Slope gradients range from 10 to 30 percent. Soils on this landform

are deep and well drained. These soils are poorly developed in very gravelly

or stony colluvium The dominant soils are classified as Typic and Andic

Cryochrepts. Rock outcrop occurs on 10-40 percent of this landscape

component. The dominant potential natural vegetation is subalpine fir and

whitebark pine-subalpine fir series. This component represents 30 percent of

this unit.

Compiled by: Robin Strathy, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 188
LTA74-M332C

FROST SHATTERED MOUNTAIN RIDGE TOPS: SANDSTONES AND SHALES

Location: This LTA occurs on the Lewis and Clark National Forest.

 Acreage by Section

 74-M332C 3,827

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of frost shattered ridges and slopes.

Parent materials are residuum and colluvium underlain by sandstone shale, and

other mixed sedimentary bedrock.

Accessory Characteristics: The primary soils are shallow to moderately deep

with stoney loamy textures. The vegetation is a mosaic of coniferous forest

and mountain grasslands. Mean annual precipitation ranges from 51 to 152

centimeters (20 to 60 inches). The elevation range of this LTA is 1525 to 2074

meters (5000 to 6800 feet). The dominant slopes have gradients of 30 to 60

percent. This LTA is slightly dissected by streams, with no apparent dominant

stream pattern. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of frost shattered ridges

and slopes.

Frost shattered ridges and slopes are formed in sandstone, shale and other

mixed sedimentary bedrock. Slope gradients range from 25 to 60 percent. Soils

on these landforms are moderately deep, weakly developed, withstoney loamy

textures. These soils are classified as Lithic and Typic Cryoborolls, and

Typic and Andic Cryochrepts. Rock outcrop occurs on about 10 to 30 percent of

this landscape component and scree occupies an equal, and sometimes larger,

area. The dominant potential natural vegetation is subalpine fir series. This

component represents 100 percent of this LTA.

Compiled by: Robin Strathy, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 189
LTA83-M332C

LTA83-M332D

LOW RELIEF HILLS: FINE TERTIARY SEDIMENTS

Location: This LTA is located on gently to moderately sloping hills in the

Little Belt Mountains with minor amounts on the Rocky Mountain Front on the

Lewis and Clark National Forest.

 Acreage by Section

 83-M332C 329

 83-M332D 18,662

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a low relief hills

setting, which is typically composed of old clayey deposits. Parent materials

are residuum underlain by sedimentary rocks, usually sandstones and shales.

Accessory Characteristics: The primary soils are moderately deep with loamy

and clayey textures. The vegetation is coniferous forest. Mean annual

precipitation ranges from 51 to 76 centimeters (20 to 30 inches). The

elevation range of this LTA is 1676 to 2286 meters (5500 to 7500 feet). The

dominant slopes have gradients of 0 to 25 percent. This LTA is moderately

dissected by streams, with the dominant stream pattern being parallel. Wetlands

are a minor component of this LTA.

LTA Components: This landtype association consists of old clayey alluvial

deposits.

Old clayey alluvial deposits are formed in sandstone and shale sedimentary

rocks. Slope gradients range from 0 to 25 percent. Soils on these landforms

are moderately deep, strongly developed, with loamy and clayey textures. These

soils are classified as Aquic Cryoboralfs. Rock outcrop generally is not found

in this landscape component. The dominant potential natural vegetation is

alpine fir habitat types. This component represents 100 percent of this LTA.

Compiled by: Robin Strathy, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 190
LTA90-M332C

LTA90-M332D

LTA90-331D

MASS WASTED SLOPES: MIXED GEOLOGY

Location: This LTA is located primarily in the Little Belt and Big Snowy

Mountain Ranges.

 Acreage by Section

 90-M332C 67,272

 90-M332D 73,847

 90-331D 2,576

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountainous landscape

setting, which is typically composed of valley sideslopes and benchy lower

valley slopes. Parent material is shale.

Accessory Characteristics: The primary soils are deep, clayey and

loamy-skeletal silt loams and silty clay loams. The vegetation is coniferous

forest. Mean annual precipitation is 51 to 76 centimeters (20 to 30 inches).

The elevation range of this LTA is 1372 to 2134 meters (4500 to 7000 feet).

The dominant slopes have gradients of 10 to 40 percent. This LTA is moderately

dissected, with the dominant stream pattern being dendritic.

LTA Components: This landtype association consists of rotational slumps and

mud flows, benchy lower valley slopes, and upper valley sideslopes.

Rotational slumps and mud flows are formed in shale. Slope gradients range

from 10 to 40 percent. Soils on these landforms are moderately deep, weakly

developed, and consist of mainly of loam, silt loam, and cobbles. The major soils

are classified as Typic Cryochrepts. Rock outcrop occurs on less than 15

percent of this LTA. The dominant potential natural vegetation is subalpine

fir series. This component represents 55 percent of this LTA.

Benchy lower valley slopes are formed in shale. Slope gradients range from 10

to 40 percent. Soils on these landforms are moderately deep and deep, weakly

developed, and consist of loam, silt loam and gravel. The major soils are

classified as Typic Cryoboralfs. Rock outcrop occurs on less than 15 percent

of this LTA. The dominant potential natural vegetation is the Douglas-fir

series. This component represents 30 percent of this LTA.

Upper valley sideslopes are formed in shale. Slope gradients range from 10 to

25 percent. Soils on these landforms shallow, moderately developed and consist

mainly of loam and cobble. The major soils are classified as Mollic

Cryoboralfs. Rock outcrop occurs on less than 15 percent of this LTA. The

dominant potential natural vegetation is Douglas-fir series. This component

represents 15 percent of this LTA.

Compiled by: Richard Saunders, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 191
CHAPTER 8

LTA Descriptions

Section M332D Belt Mountains

This Section occurs in central Montana and generally coincides with the

Central Montana Island Mountains geomorphic area previously described. Forty

five LTAs were mapped in this Section. See Appendix F for a complete list of

the LTAs and their acreages. Map unit descriptions are preceded by the

following illustrations:

 Figure 30: Map showing location of M332D within the Northern Region

 Figure 31: Section M332D Moderately and Highly Weathered Granitic 

 Mountains, landscape photograph.

 Southwestern Elkhorn Mountains, Helena National Forest

 Figure 32: Map showing distribution of LTAS within M332D

 Figure 33: Bar chart showing abundance of landform groups within M332D

 Figure 34: Bar chart showing abundance of geologic material groups 

 within M332D

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 192
LTA10-M332Dj

VALLEYS: RECENT COARSE ALLUVIUM

Location: This LTA is located in the Boulder Mountains, Beaverhead-Deerlodge

National Forest, southwest Montana, in the upper Jefferson River Basin.

 Acreage by Subsection

 10-M332Dj 9,182

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a valley bottom landscape

setting, which is typically composed of floodplains and terraces. Parent

material is alluvium deposited on a variety of bedrock types.

Accessory Characteristics: The primary soils are deep with cobbly sandy and

loamy textures. The vegetation is a mosaic of grassland, shrublands, and

coniferous forest. Mean annual precipitation ranges from 36 to 51 centimeters

(14 to 20 inches). The elevation range of this LTA is 1677 to 1982 meters

(5500 to 6500 feet). The dominant slopes have gradients of 0 to 20 percent.

This LTA is slightly dissected by streams, with the dominant stream pattern

being NA. Wetlands are a major component of this LTA.

LTA Components: This landtype association consists of floodplains, and

terraces.

Floodplains are formed in coarse alluvium. Slope gradients range from 0 to 10

percent. Soils on these landforms are deep, weakly developed, with cobbly

sandy and loamy textures. These soils are classified as Typic Cryochrepts and

Cryaquolls, and Typic and Aquic Cryochrepts and Cryoborolls. Rock outcrop

does not occur on this landscape component. The dominant potential natural

vegetation is willow, sedge, spruce, and subalpine fir series. This component

represents 60 percent of this LTA.

Terraces are formed in coarse alluvium. Slope gradients range from 0 to 20

percent. Soils on these landforms are deep, weakly developed, with cobbly

sandy and loamy textures. These soils are classified as Typic Cryoboralfs,

Cryochrepts, and Cryoborolls. Rock outcrop does not occur on this landscape

component. The dominant potential natural vegetation is Idaho fescue,

sagebrush, Douglas-fir and subalpine fir series. This component represents 40

percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 193
LTA10-M332D

LTA10-M332C

LTA10-331D

VALLEYS: RECENT COARSE ALLUVIUM

Location: This LTA is located in all mountain ranges of the Lewis and Clark

and Helena National Forests.

 Acreage by Section

 10-M332D 77,706 (Section except for M332Dj)

 10-M332C 17,094

 10-331D 982

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a valley bottom landscape

setting which is usually composed of stream terraces, floodplains, and

alluvial fans. Parent materials are stratified alluvial deposits of sands,

silts and gravels.

Accessory Characteristics: The primary soils are deep gravelly to extremely

gravelly sandy loams and loams. The vegetation is a mosaic of deciduous

forest, coniferous forest, well drained grassland and wet meadow. Mean annual

precipitation ranges from 38 to 75 centimeters (15 to 30 inches). The

elevation range of this LTA is 1159 to 1983 meters (3800 to 6500 feet). The

dominant slopes are 0 to 4 percent. This LTA by nature has very high stream

densities. Wetlands are an important component of this LTA.

LTA Components: This landtype association consists of floodplains, and stream

terraces/and alluvial fans.

Floodplains and lower terraces are formed in a variety of stratifie d alluvium 

These floodplains have slope gradients that range from 0 to 2 percent. Soils

on these landforms are very deep, poorly developed, and consist mainly of

sand, gravel and cobble. Silts and clays are found to a lesser extent in oxbow

positions and areas historically occupied by beaver dams. The major soils are

highly variable and include Fluvents, Aquepts, Aquepts, Aquolls and Borolls.

The dominant potential natural vegetation is Englemann spruce and subalpine

fir series, with inclusions of black cottonwood. This component represents 60

percent of this LTA.

Higher terraces and included fans are formed in alluvium. These terraces have

slope gradients that range from 0 to 4 percent. The alluvial fans often have

slope gradients of 8 to 25 percent. Soils on these landforms are deep, poorly

to well developed, and consist mainly of gravelly to extremely gravelly sandy

loams and loams. Sand, gravel and/or cobble layers or lenses are often

present. Areas of silt and clay are present in old oxbow and beaver dam

locations as well as glacial ice dams. The major soils are classified as

Haploborolls and Cryoborolls. The dominant potential natural vegetation is

Douglas-fir, rough fescue, and big sagebrush series. This component represents

40 percent of this LTA.

Compiled by: Richard Saunders, Lewis and Clark National Forest

Revised by Larry Laing, Helena and Lewis and Clark National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 194
LTA12-M332D

VALLEYS:ALLUVIAL FANS,GLACIAL TERRACES

COARSE ALLUVIAL AND GLACIOFLUVIAL DEPOSITS

Location: This LTA is located in foothills near the Boulder, Highland, and

Tobacco Root Mountains on the Beaverhead-Deerlodge National Forest in

southwest Montana. It occurs in the upper Boulder and Jefferson River basins.

 Acreage by Subsection

 12-M332D 60,591 (Section except M332Db)

 

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a valley landscape

setting, which is typically composed of alluvial fans and glacial terraces.

Parent materials are coarse alluvium and glacial outwash over undifferentiated

bedrock.

Accessory Characteristics: The primary soils are deep with cobbly and

gravelly sandy and loamy textures. The vegetation is a mosaic of shrublands

and grasslands with minor inclusions of coniferous forest. Mean annual

precipitation ranges from 23 to 46 centimeters (9 to 18 inches). The elevation

range of this LTA is 1373 to 1951 meters (4500 to 6400 feet). The dominant

slopes have gradients of 5 to 15 percent. This LTA is moderately to highly

dissected by intermittent streams, with the dominant stream pattern being

parallel. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of two landform

components: alluvial fans and glacial terraces.

Alluvial fans are formed in coarse alluvial and glaciofluvial deposits

originating from a variety of bedrock types. The majority of this LTA consists

of a series of coalescing alluvial fans. Slope gradients range from 1 to 15

percent. Soils on these landforms are moderately deep to deep, are weakly to

moderately developed; and have cobbly and gravelly sandy loam and loam surface

soils. The subsurface layers are cobbly sandy loams and loams in the less

developed soils and cobbly sandy clay loams and clay loams where subsoil clay

accumulation occurs. These soils are classified as Ustochrepts, Argiborolls,

and Haploborolls. Rock outcrop occurs on less than 1 percent of this landscape

component. The dominant potential natural vegetation is needle-andthread/bluegrama; bluebunch wheatgrass/blue grama, and sagebrush/bluebunch

wheatgrass habitat types. This component represents 95 percent of this LTA.

Glacial terraces are formed in coarse glaciofluvial deposits. This component

is represented by one mapping unit at the mouth of Rock Creek in the upper

Boulder River. Slope gradients range from 0 to 20 percent. Soils on this

landform are deep, weakly to moderately developed; with cobbly sandy and loamy

textures. They are classified as Typic Cryochrepts and Cryoboralfs, and Argic

and Typic Cryoborolls. Rock outcrop does not occur in this landform component.

The dominant potential natural vegetation is a mosiac of Douglas

fir/twinflower; dwarf huckleberry/pinegrass; sagebrush/rough fescue or rough

fescue/Idaho fescue habitat types. This component represents 5 percent of this

LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 195
LTA12-M332Db

LTA12-M331A

VALLEYS: OUTWASH AND OTHER OLDER COARSE

ALLUVIAL DEPOSITS

Location: This unit is located mostly in the Beartooth, Madison and southern

Gallatin mountain ranges in southwestern Montana with some delineations in the

Bridger and Crazy Mountains.

 Acreage by Subsection

 12-M332Db 8,115

 12-M331A 59,997

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit consists of gently sloping

glacial outwash plains, alluvial fans, and terraces with some landflows.

Parent material is coarse textured glaciofluvial deposits with some mixed

loess (wind blown silt) in the soils' surface layer.

Accessory Characteristics: Vegetation is dense lodgepole pine forest,

scattered Douglas-fir forest, or mountain grassland. Elevation ranges from

1560 to 2438 meters (5200 to 8000 feet). Mean annual precipitation is 38 to

81 centimeters (15 to 32 inches). Slopes range from 0 to 40 percent.

LTA Components: This LTA has two components depending upon the vegetation.

Where vegetation is grassland, soils are Typic and Aridic Argiborolls with

some carbonatic soils such as Typic Cryoborolls, Calcic Cryoborolls, and

Ustollic Haplargids. These soils are deep, moderately coarse to medium

textured, rocky, and have moderate fertility and water holding capacity. 

Common potential vegetation is big sagebrush and Idaho fescue series. This

component makes up 40 percent of the LTA.

Where vegetation is lodgepole pine forest or Douglas-fir forest, soils are

Typic Cryochrepts or Typic Cryoboralfs. These soils are moderately coarse to

medium textured, rocky, and have very low to moderate fertility and water

holding capacity. A common potential vegetation is lodgepole pine near Hebgen

Lake in the Gallatin Range. This component makes up 60 percent of the LTA.

Compiled by: Henry Shovic, Gallatin National Forest and John R. Lane, Custer

National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 196
LTA14-M332D

VALLEYS: FINE ALLUVIUM

Location: This LTA is located in the Whitetail Creek valley on the

Beaverhead-Deerlodge National Forest in southwest Montana. It occurs in the

Upper Jefferson River basin.

 Acreage by Section

 14-M332D 2,606

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in large valley bottoms

which are typically composed of flood plains and terraces. Parent materials

are recent alluvium.

Accessory Characteristics: The primary soils are deep with fine textures,

some with organic layers on and near the surface. The vegetation is a mosaic

of meadows and riparian shrubs, and deciduous tree species. Mean annual

precipitation is about 25 cms. (10 inches). The elevation range is 1310 to

1400 meters (4300 to 4600 feet). The dominant slopes have gradients of 0 to 10

percent. This LTA is highly dissected by streams, with the dominant stream

pattern being dendritic. Wetlands are a major component of this LTA.

LTA Components: This landtype association consists of two landform

components: flood plains and terraces.

Flood plains are formed in variable alluvium, typically finer and/or organic

near the surface. Slope gradients vary from 0 to 5 percent. Soils on these

landforms are deep, weakly to moderately developed, poorly drained sands and

silts, often with organic layers. Dominant soils are classified asAquolls and

Borolls. The potential natural vegetation is a variety of riparian

communities and habitat types. This component represents about 50 percent of

this LTA.

Terraces are formed in fine alluvium. Slope gradients range from 2 to 10

percent. Soils on this landform are deep, somewhat poorly to well drained, and

moderately developed. They are classified as Argiborolls and Ustochrepts. The

dominant vegetation is a variety of dry and moist grass and shrub habitat

types with significant areas converted to pastures and irrigated hay meadows.

 This component represents about 50 percent of this unit.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 197
LTA20-M332D

BREAKS: METASEDIMENTARY (BELT)

Location: This LTA is located in the Missouri River Basin in the Big Belt,

Elkhorn, and Alice Nevada Mountains.

 Acreage by Section

 20-M332D 13,713

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a very steep, deeply

eroded or faulted mountainous landscape setting, which is typically composed

of structural breaks. Parent materials are colluvium and residuum underlain by

metasedimentary (mainly argillite, siltite and quartzite) and volcanic bedrock

(basalts and andesites). They are medium textured with high rock contents

throughout.

Accessory Characteristics: The primary soils are shallow and moderately deep.

The vegetation is a mosaic of coniferous forest and forested scree, with

substantial rock outcrops. Mean annual precipitation ranges from 25 to 75

centimeters (10 to 30 inches). The elevation range of this LTA is 1220 to 2288

meters (4000 to 7500 feet). The dominant slopes have gradients of 60 to 90

percent. This LTA is highly to slightly dissected (closely to widely spaced

drainages) and weakly or moderately incised by streams, with the dominant

stream patterns being dendritic and sub-parallel.

LTA Components: This landtype association consists of structural breaks.

Structural breaks are formed in colluvium and residiuum. Slope gradients range

from 60 to 90 percent. Soils on these landforms are shallow and moderately

deep, weakly developed and are loams with high amounts of pebbles and channers

throughout. These soils are classified as Lithic Ustochrepts, and Lithic and

Typic Cryochrepts. Rock outcrop occurs on about 30 percent of this landscape

component. The dominant potential natural vegetation series are Douglas-fir,

subalpine fir, and limber pine on warmer aspects with subalpine fir and

Douglas-fir on more northerly aspects. This component represents 100 percent

of this LTA.

Compiled by: Larry Laing. Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 198
LTA21-M332D

LTA21-M332E

BREAKS: HIGHLY WEATHERED GRANITICS

Location: This LTA is located in the Anaconda-Pintlar, Fleecer, Pioneer,

Boulder, Bull, Highland, and Tobacco Root Mountains on the Beaverhead

/Deerlodge National Forest in the Jefferson and Madison River Basins in

southwest Montana.

 Acreage by Section

 

 21-M332D 8,423

 21-M332E 41,402

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in steep, deeply eroded

(rejuvenated), or faulted mountainous landscape settings which is typically

composed of structural and stream breaks. Parent materials are colluvium and

residuum derived from moderately to highly weathered Cretaceous to Tertiary

intrusive rocks undifferentiated, consisting mainly of granite, quartz

monzonite, and granodiorite.

Accessory Characteristics: The primary soils are shallow to moderately deep,

well drained, gravelly sandy loams. The vegetation is a mosaic of coniferous

forest and mountain grasslands. Mean annual precipitation ranges from 41 to

102 centimeters (16 to 40 inches). The elevation range of this LTA is 2012 to

3048 meters (6600 to 10000 feet). The dominant slopes have gradients of 40 to

75 percent. This LTA is highly to moderately dissected by streams, with the

dominant stream pattern being dendritic to parallel. 

LTA Components: This landtype association consists of breaks. 

Breaks are formed in colluvium and residuum. Slope gradients range from 40 to

75 percent. Soils on these landforms are shallow to moderately deep, weakly

developed, well drained, channery sandy loams and loams. These soils are

classified as Typic Cryorthents, and Lithic and Typic Cryochrepts. Rock

outcrop accounts for up to a quarter of this landscape component. The

dominant potential natural vegetation is Douglas-fir, big sagebrush, subalpine

fir and whitebark pine series. This component represents 100 percent of this

LTA.

Compiled by: Dan Svoboda and Dave Ruppert, Beaverhead-DeerLodge National

Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 199
LTA24-M332D

BREAKS: VOLCANICS

Location: This LTA is located in the Boulder Mountains of southwest Montana

in the Jefferson River basin. It occurs mostly on the Beaverhead-Deerlodge

National Forest.

 Acreage by Section

 24-M332D 4,485

LTA Setting and General Characteristics

Differentiating characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of stream breaks. Parent materials are

residuum underlain by volcanic bedrock.

Accessory characteristics: The primary soils are shallow and moderately deep

with cobbly loamy textures. The vegetation is a mosaic of grasslands,

shrublands, coniferous forest, and rock. Mean annual precipitation ranges from

41 to 51 centimeters (16 to 20 inches). The elevation range of this LTA is

1677 to 2134 meters (5500 to 7000 feet). The dominant slopes have gradients of

45 to 80 percent. This LTA is moderately dissected by streams, with the

dominant stream pattern being parallel. Wetlands are a minor component of

this LTA.

LTA Components: This landtype association consists of stream breaks.

Stream breaks are formed in volcanic bedrock. Slope gradients range from 45 to

80 percent. Soils on these landforms are shallow and moderately deep, weakly

developed, and have cobbly loamy textures. These soils are classified as Typic

and Lithic Cryochrepts and Cryorthents. Rock outcrop occurs on about 30

percent of this landscape component. The dominant potential natural vegetation

is forested scree, Idaho fescue, sagebrush, and Douglas-fir series. This

component represents 100 percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 200
LTA25-M332D

LTA25-M331A

BREAKS: SANDSTONES AND SHALES

Location: This unit is located in the Beartooth, Bridger, Crazy, Gallatin and

Madison mountain ranges in southwestern Montana.

 Acreage by Section

 25-M332D 20,570

 25-M331A 69,798

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit consists of steep to

moderately steep ridges and slopes whose shape is controlled by underlying

bedrock structure. Soil parent material is colluvium and residuum derived from

thickly interbedded limestone, sandstone, and shale.

Accessory Characteristics: Vegetation is sparse to dense forest with some

meadows and grassland. Elevation ranges from 1830 to 2640 meters (6000 to 8800

feet). Mean annual precipitation is 58 to 127 cms. (23 to 50 inches). Slopes

are greater than 40 percent.

LTA Components: This landtype association consists of two components.

Where vegetation is sparse Douglas-fir forest and grasslands, soils are Argic

Cryoborolls, and Mollic Cryoboralfs. These soils are medium to moderately fine

textured, rocky or non-rocky, with moderate to high fertility and water

holding capacity. Where bedrock is limestone, soils are Lithic and Typic

Calciborolls, and Calcic Cryoborolls. Rock outcrop makes up 10 to 25 percent

of this component. Common potential vegetation includes Douglas -fir, Idaho

fescue, and big sagebrush series. This component makes up 50 percent of this

LTA.

Where vegetation is dense forest and meadows, soils are Mollic and Typic

Cryoboralfs, Typic Cryochrepts, and Argic Cryoborolls. These soils are medium

to moderately fine textured, rocky or non-rocky, and have moderate fertility

and water holding capacity. Rock outcrop makes up 10 to 25 percent of this

component. Common potential vegetation includes Douglas-fir, subalpine fir,

Idaho fescue and subalpine fir-whitebark pine series. This component makes up

50 percent of this LTA.

Compiled by: Henry Shovic, Gallatin National Forest and John R. Lane, Custer

National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 201
LTA27-M332D

BREAKS: CARBONATES

Location: This LTA is located in the Big Belt, Little Belt, and Snowy

Mountains in the Missouri River basin.

 Acreage by Section

 27-M332D 235,563

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a very steep, deeply

eroded or faulted mountainous landscape setting, which is typically composed

of structural breaks. Parent materials are colluvium and residuum underlain

by limestone.

Accessory Characteristics: The primary soils are moderately deep or deeper.

They are medium textured with high rock contents throughout. The vegetation

is a mosaic of coniferous forest and forested scree, with substantial rock

outcrops. Mean annual precipitation ranges from 25 to 75 centimeters (10 to

30 inches). The elevation range of this LTA is 1159 to 2288 meters (3800 to

7500 feet). The dominant slopes have gradients of 60 to 90 percent. This LTA

is highly to slightly dissected (closely to widely spaced drainages) and

weakly or moderately incised by streams, with the dominant stream patterns

being subparallel.

LTA Components: This landtype association consists of structural breaks.

Structural breaks are formed in colluvium and residiuum. Slope gradients range

from 60 to 90 percent. Soils on these landforms are mostly moderately deep or

deeper to bedrock, weakly developed and are loams dominated by gravel size

rock fragments throughout. These soils are classified as Typic Ustochrepts

and Typic Cryochrepts. Rock outcrop and associated talus occurs on about 40 to

50 percent or more over much of this landscape component. The amount of rock

outcrop and scree is around 20 percent or less. The dominant potential natural

vegetation is Douglas-fir series on higher energy aspects and subalpine fir

and spruce series on more northerly aspects. Forested and nonforested scree

occur throughout. This component represents 100 percent of this LTA.

Compiled by: Larry Laing, Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 202
LTA34-M332Dj

LTA34-M332De

HIGH RELIEF MOUNTAIN SLOPES: VOLCANICS

Location: This LTA is located in the Blackfoot River Drainage.

 Acreage by Subsection

 34-M332Dj 2,786

 34-M332De 10,644

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a mountainous landscape

setting which is typically composed of steep mountain slopes. Parent material

is colluvium and residuum underlain by weakly weathered andesite and other

volcanic rocks. In some areas the parent material is influenced by a complex

of volcanic and metasedimentary Belt Series rocks.

Accessory Characteristics: The primary soils are moderately deep or deeper

and are medium to moderately fine textured. The vegetation is coniferous

forest. Mean annual precipitation ranges from 50 to 75 centimeters (20 to 30

inches). The elevation range of this LTA is 1464 to 2135 meters (4800 to 7000

feet). The dominant slopes have gradients of 25 to 60 percent. This LTA is

moderately dissected (moderately to widely spaced drainages) and deeply

incised by streams, with the dominant stream pattern being dendritic. Small

wetlands are sometimes associated with slumpy areas.

LTA Components: This landtype association consists of steep, mountain slopes.

Steep mountain slopes are mostly formed in andesite and other volcanic rock.

In some areas they are influenced by a complex of volcanic and metasedimentary

Belt Series rocks. Slope gradients range from 25 to 60 percent. Soils on

these landforms are moderately deep to very deep, moderately developed, and

have very gravelly or gravelly loam, cobbly loam and stony loam surfaces.

Subsurface textures include very and extremely stony clay loam, very and

extremely cobbly loams, very gravelly clay loam and extremely gravelly loam.

These soils are classified as Typic Cryoboralfs, Typic Eutroboralfs and Typic

Agriborolls. Rock outcrop occurs on less than 5 percent of this landscape

component. Small landslides are associated with basaltic and andesitic dikes

and sills or local ash/tuff deposits. The dominant potential natural

vegetation is Douglas-fir and subalpine fir series. This component represents

100 percent of this LTA.

Compiled by: Larry Laing, Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 203
LTA34-M332Db

LTA34-M332C

LTA34-331D

HIGH RELIEF MOUNTAIN SLOPES: VOLCANICS

Location: This LTA is located in the Highwood, Little Belt, and Crazy

Mountains.

 Acreage by Section

 34-M332Db 1,277

 34-M332C 233

 34-331D 6,622

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs on very steep mountain

slopes composed of convex ridges and shoulders in complex with smooth

surfaces. Parent material is sandstone, granite, and basalt.

Accessory Characteristics: The primary soil is shallow to moderately deep

very gravelly or stony loam or sandy loam. The vegetation is coniferous

forest. Mean annual precipitation ranges from 46 to 76 centimeters (18 to 30

inches). The elevation range is 1830 to 2288 meters (6,000 to 7,500 feet). The

dominant slopes have gradients of greater than 60 percent. This LTA is

slightly dissected by streams with the dominant stream pattern being

dendritic. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of very steep mountain

slopes.

These mountain slopes are formed in sandstone, granite and basalt. Slope

gradient is greater than 60 percent. Soil on this landform is shallow to

moderately deep, weakly developed and consists mainly of very gravelly or

stony colluvial material. These soils are classified as Typic Cryochrepts.

Typically 10 to 25 percent of this association consists of rock outcrop. The

dominant potential vegetation is subalpine fir series with some scree. This

component represents the entirety of this LTA.

Compiled by: Rich Saunders, Lewis and Clark National Forest

Revised by Larry Laing, Helena/Lewis and Clark National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 204
LTA36-M332D

LTA36-M332C

LTA36-331D

HIGH RELIEF MOUNTAIN SLOPES: SANDSTONES AND SHALES

Location: This LTA is located throughout the Lewis and Clark National Forest

except in the Little Snowy Mountains.

 Acreage by Section

 36-M332D 12,477

 36-M332C 13,447

 36-331D 764

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs on very steep unglaciated

mountain slopes typically composed of convex ridges and shoulders in complex

with smooth surfaces. Parent materials are non-carbonate and sedimentary.

Accessory Characteristics: The primary soils are shallow to moderately deep

extremely gravelly loams. The vegetation is coniferous forest. Mean annual

precipitation ranges from 51 to 102 centimeters (20 to 40 inches). The

elevation range of this LTA is 1829 to 2743 meters (6000 to 9000 feet). The

dominant slopes have gradients of greater than 60 percent. This LTA is

slightly dissected by streams with the dominant stream pattern being radial. 

Wetlands and lakes are virtually non-existent in this LTA.

LTA Components: This landtype association consists of convex ridges, and

shoulders in complex with smooth surfaces. All of these landforms occur on

non-carbonate sedimentary parent material.

The convex ridges and shoulders have slope gradient of 25 to greater than 60

percent. Soils on these landforms are shallow to moderately deep, poorly

developed, and consist mainly of extremely gravelly sandy loam. The major

soils are classified as Typic Cryochrepts. Rock outcrop and talus occur on 75

percent of this unit. The dominant potential natural vegetation series is

subalpine fir-whitebark pine.

Compiled by: Richard Saunders, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 205
LTA37-M332D

HIGH RELIEF MOUNTAIN SLOPES: CARBONATES

Location: This LTA is located in the Big Belt, Dry Range and South Elkhorn

Mountains, part of the Missouri River basin.

 Acreage by Section

 37-M332D 46,970

LTA Settings and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountainous landscape

setting, which is typically composed of mountain slopes and dipslopes. Parent

materials are colluvium and residuum underlain by limestone sometimes

associated with calcareous shales.

Accessory Characteristics: The primary soils are moderately deep and shallow

and have medium textured surfaces. The vegetation is coniferous forest with

inclusions of mountain grassland. Mean annual precipitation ranges from 38 to

76 centimeters (15 to 30 inches). The elevation range of this LTA is 1068 to

2196 meters (3500 to 7200 feet). The dominant slopes have gradients of 40 to

60 percent. This LTA is highly to slightly (widely to closely spaced

drainages) and has weakly to deeply incised drainages. The dominant stream

patterns are dendritic and subparallel.

LTA Components: This landtype association consists of mountain slopes, and

dipslopes.

Mountain slopes are formed in colluvium and residuum from limestone sometimes

with included calcareous shales and argillites. Slope gradients range from 40

to 60 percent. Soils on these landforms are moderately deep and shallow and

weakly developed, although some soils have thick dark surface layers. Surface

textures are very gravelly loams and gravelly, very gravelly and extremely

gravelly silt loams. Subsurface layers have extremely gravelly loam, extremely

gravelly silt loam, very gravelly silt loam, very gravelly loam and very,

gravelly silty clay loam textures. These soils are classified as Typic and

Lithic Ustochrepts, Typic Cryochrepts, Typic Calciborolls, Calcic Cryoborolls

and Lithic Ustochrepts. Rock outcrop occurs on about 10 percent of this

landscape component. The dominant potential natural vegetation series is

Douglas-fir with ponderosa pine at lower elevations on some steep southerly

aspects. Subalpine fir and spruce can occur on northerly aspects at higher

elevations. This component represents 76 percent of this LTA.

Dip slopes are formed in colluvium and residuum formed in limestone and

calcareous sandstone. Slope gradients range from 40 to 60 percent. Soils on

these landforms are moderately deep and shallow and are weakly developed.

Surface soils have extremely gravelly silt loam and gravelly silty clay loam

textures. The subsurface layers are typically very gravelly silty clay loam

and very gravelly silt loam. These soils are classified as Typic and Lithic

Cryochrepts. Rock outcrop occurs on about 30 percent of this landscape

component. The dominant potential natural vegetation series is Douglas-fir.

This component represents 24 percent of this LTA.

Compiled by: Larry Laing, Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 206
LTA39-M332D

STEEP GLACIATED MOUNTAIN SLOPES: GNEISSES AND SCHISTS

Location: This LTA is located in the Little Belt Mountains of the Lewis and

Clark National Forest in west-central Montana in the Missouri River Basin.

 Acreage by Section

 39-M332D 5,300

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a steep mountain

landscape setting, which is typically composed of rockland and scree. Parent

materials are residuum underlain by gneiss and schist bedrock.

Accessory Characteristics: Soils are weakly developed in very stoney

colluvium. Active movement of loose rock is common. The vegetation is a

mosaic of rock outcrop, scree, and coniferous forest. Mean annual

precipitation ranges from 64 to 89 centimeters (25 to 35 inches). The

elevation range of this LTA is 1829 to 2286 meters (6000 to 7500 feet). The

dominant slopes have gradients over 60 percent. This LTA is moderately

dissected by streams, with the dominant stream pattern being parallel.

Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of steep mountain slopes.

Mountain slopes are formed in gneiss and schist bedrock. Slope gradients range

from 60 to 100 percent. Soils on these landforms are shallow and moderately

deep, weakly developed, with stoney textures. These soils are classified as

Typic Cryochrepts. Rock outcrop and scree occur on 40 to 90 percent of this

landscape component. The dominant potential natural vegetation is subalpine

fir and scree. This component represents 100 percent of this LTA.

Compiled by: Robin Strathy, Lewis and Clark National Forest.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 207
LTA40-M332D

STEEP GLACIATED MOUNTAIN SLOPES: METASEDIMENTARY (BELT)

Location: This unit is located in the Big Belt Mountains of the Upper

Missouri River Basin of west central Montana.

 Acreage by Section

 

 40-M332D 7,828

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a steep, alpine

glaciated landscape setting. Parent materials are metasediments composed of

argillites, siltites and quartzites with alpine glacial till scattered

throughout, which is typically medium textured.

Accessory Characteristics: The primary soils are shallow to moderately deep.

They are moderately coarse to medium textured. The vegetation is a mosaic of

coniferous forest, avalanche chutes, and rock outcrops. Mean annual

precipitation ranges from 50 to 113 centimeters (20 to 45 inches). The

elevation range of this unit is 1846 to 2923 meters (6000 to 9500 feet). The

dominant slopes have gradients greater than 60 percent. This map unit is

moderately to highly dissected by streams, with the dominant stream pattern

being parallel. Wet sidehill areas are a major component of this unit.

LTA Components: This landtype association consists of steep glaciated

mountain slopes.

Steep glaciated mountain slopes are formed in metasediments that consist of

argillites, siltites and quartzites. The primary landforms include glacial

cirque basins and headwalls and glacial trough walls. They have been strongly

scoured and often contain shallow soils and rock outcrops. The lower slopes

can have glacial till depositions. Slopes range from 25 to 100 percent, but

the dominant slopes are greater than 60 percent. The major soils are

classified as Andic Cryochrepts in the cirque basins. The dominant potential

natural vegetation in the cirques is subalpine fir and whitebark pine

/subalpine fir habitat types. The major soils associated with the glacial

trough walls include Typic Ustochrepts, Andic Cryochrepts and Typic

Cryoboralfs. Rock outcrops also occur. The dominant potential natural

vegetation on the trough walls is Douglas-fir and subalpine fir series as well

as forested scree. The soils and vegetation associated with these extremely

steep slopes are strongly controlled by aspect.

Compiled by: Larry Laing, Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 208
LTA41-M332Dc

LTA41-M331A

STEEP GLACIATED MOUNTAIN SLOPES: GRANITICS

Location: This unit is located in the Gallatin and Crazy mountain ranges in

southwestern Montana.

 Acreage by Section

 41-M332Dc 72,095

 41-M331A 117,173

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit consists of steep glacial

troughwalls with weak stream dissection. Included are some talus slopes and

rock glaciers. Soil parent material is colluvium and glacial till derived

from coarse grained, shallow intrusive rocks.

Accessory Characteristics: Vegetation is sparse to dense upper subalpine,

lower subalpine, or Douglas-fir forest. Slopes are greater than 40 percent.

Elevation ranges from 1768 to 2743 meters (5800 to 9000 feet). Mean annual

precipitation is 63 to greater than 125 centimeters (25 to greater than 50

inches).

LTA Components: This LTA has two components:

Soils where vegetation is either Douglas-fir or lower subalpine forest are

Udic Ustochrepts or Dystric Cryochrepts. These soils are deep, moderately

coarse to coarse textured, rocky, and have low fertility and water holding

capacity. Rock outcrop makes up 20 to 30 percent of this component. Common

potential vegetation includes the subalpine fir and Douglas-fir series. This

component makes up 35 percent of this LTA.

Soils where vegetation is sparse upper subalpine forest or nearly absent are

Cryochrepts. They are deep to shallow, and generally coarse textured with very

low fertility and water holding capacity. Rock outcrop makes up 50 to 90

percent of this component. Where forested, a common potential vegetation is

the subalpine fir-whitebark pine series. This component makes up 65 percent of

this LTA.

Compiled by: Henry Shovic, Gallatin National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 209
LTA41-M332D

STEEP GLACIATED MOUNTAIN SLOPES: GRANITIC

Location: This LTA is located in the Big Belt Mountains, the upper Ten Mile

Creek drainage and the Elkhorn Mountains.

 Acreage by Section

 41-M332D 28,251 (Section except M332Dc)

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in an alpine glaciated

mountainous landscape setting which is typically composed of glacial trough

walls. Parent material is glacial till underlain by weakly weathered granite,

granite-diorite and diorites. Northerly aspects have volcanic ash influenced

surface soils.

Accessory Characteristics: The primary soils are deep and moderately coarse

textured. The vegetation is a mosaic of coniferous forest and foreste d scree 

Mean annual precipitation ranges from 50 to 100 centimeters (20 to 40 inches).

The elevation range of this LTA is 1678 to 2501 meters (5500 to 8200 feet).

The dominant slopes have gradients of 60 to 90 percent. This LTA is highly

dissected (closely spaced drainages) and weakly incised by streams, with the

dominant stream pattern being parallel.

LTA Components: This landtype association consists of glacial trough walls.

Glacial trough walls are formed in weakly weathered granite or granit-like e

rock. Slope gradients range from 60 to 90 percent. Soils on these landforms

are deep, weakly developed, and have sandy loam or loam surfaces and very to

extremely gravelly sandy loam subsurface. These soils are classified a s Typic 

Ustochrepts and Typic Cryochrepts. Rock outcrop occurs on about 40 percent of

this landscape component. The dominant potential natural vegetation series is

Douglas-fir with subalpine fir on some north facing slopes. This component

represents 100 percent of this LTA.

Compiled by: Larry Laing, Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 210
LTA42-M332D

STEEP GLACIATED MOUNTAIN SLOPES: VOLCANICS

Location: This LTA is located in the Elkhorn Mountains in southwest Montana.

 Acreage by Section

 42-M332D 23,865

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a glaciated mountain

landscape setting, which is typically composed of cirques. Parent materials

are residuum underlain by volcanic bedrock.

Accessory Characteristics: The primary soils are shallow and moderately deep

with cobbly loamy textures. The vegetation is a mosaic of coniferous forest

and rock. Mean annual precipitation ranges from 64 to 76 centimeters (25 to 30

inches). The elevation range of this LTA is 2134 to 2896 meters (7000 to 9500

feet). The dominant slopes have gradients of 60 to 100 percent. This LTA is

moderately dissected by streams, with the dominant stream pattern being

parallel. Wetlands are a major component of this LTA.

LTA Components: This landtype association consists of cirques.

Cirques are formed in volcanic bedrock. Slope gradients range from 60 to 100

percent. Soils on these landforms are shallow and moderately deep, weakly

developed, with cobbly loamy textures. These soils are classified as

Cryorthents and Cryochrepts. Rock outcrop occurs on about 50 to 90 percent of

this landscape component. The dominant potential natural vegetation is

subalpine fir series. This component represents 100 percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 211
LTA43-M332D

LTA43-M332C

LTA43-M333C

LTA43-331D

STEEP GLACIATED MOUNTAIN SLOPES: CARBONATES

Location: This LTA is located mostly on the Rocky Mountain Front and in

adjacent areas.

 Acreage by Section

 43-M332D 12,878

 43-M332C 158,089

 43-M333C 235

 43-331D 625

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occupies high elevation landscapes

where alpine glaciation has occurred. It is typically occupied by fault

escarpments (especially in M332C), cirques, troughwalls, and ridges. The

parent material is limestone.

Accessory Characteristics: The primary soils are Lithic Cryorthents and

Cryochrepts. The vegetation is coniferous forest. Mean annual precipitation

ranges from 76 to 127 centimeters (30 to 50 inches). The elevation range of

this LTA is 1524 to 2438 meters (5000 to 8000 feet). The dominant slope

gradients are 70 to 90 percent. This LTA is moderately dissected by streams

and the dominant drainage pattern is dendritic. Wetlands, lakes, and ponds are

a minor component of this LTA.

LTA Components: This landtype association consists of steep west facing

slopes, very steep glacial breaks, and rockland/scree on fault escarpments.

The steep west facing slopes are formed in limestone. These slopes have

gradient ranging from 40 to 60 percent. Soils on these landscapes are shallow,

poorly developed, and consist mainly of loam and flaggy gravel. These soils

are classified as Lithic Cryorthents. Rock outcrop occurs on less than 15

percent of this landscape component. The dominant potential vegetation series

are open growing wind deformed Douglas-fir, limber pine, and spruce on scree.

This component represents 30 percent of this LTA.

The very steep glacial breaks are formed in limestone. Slope gradients are

mainly greater than 60 percent. The soil on this landscape is deep, poorly

developed, and consist mainly of sandy-loam and gravel. These soils are

classified as Typic Cryochrepts. Rock outcrop and talus occur on seventy-five

percent of this landscape component. The dominant potential natural vegetation

series is Douglas-fir. This component represents 30 percent of this LTA.

The rockland/scree component of this LTA occur on fault escarpments in

limestone. Slopes are mainly greater than 60 percent. Soil on this landscape

consists of sandy loam, loamy sand, gravel, and cobble. These materials are

classified as scree. The dominant potential vegetation is subalpine

fir-whitebark pine. This component represents 40 percent of this LTA.

Compiled by: Richard Saunders and Robin Strathy, Lewis and Clark National

Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 212
LTA44-M332D

LTA44-M332C

LTA44-331D

STEEP GLACIATED MOUNTAIN SLOPES: SANDSTONES AND SHALES

Location: This LTA is extensive throughout the Rocky Mountain Division on the

Lewis and Clark Forest and in the Elkhorn Mountains on the

Beaverhead-Deerlodge Forest.

 Acreage by Section

 

 44-M332D 15,947

 44-M332C 101,583

 44-331D 98

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occupies high elevation landscapes

where alpine glaciation has occurred. It is typically composed of glacial

cirque headwalls, and rockland and scree on fault escarpments in Section

M332C, and glacial cirques in Section M332D. The parent material is sandstone

and/or shale. 

Accessory Characteristics: The primary soils are deep extremely cobbly sandy

loams and loams. The vegetation is coniferous forest. Mean annual

precipitation ranges from 63 to 88 centimeters (25 to 35 inches). The

elevation range of this LTA is 1500 to 2896 meters (5000 to 9000 feet). The

dominant slopes have gradients of 40 to greater than 60 percent. This landtype

is moderately dissected by streams, with the dominant stream pattern being

parallel. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of glacial cirques,

rockland, and scree on fault escarpments.

Glacial cirques are formed in sandstone and shale. Soils on these landforms

are from very shallow to moderately deep, poorly developed, and consist mainly

of sandy loam and angular cobble. The major soils are classified as Typic,

Andic and Lithic Cryochrepts. Rock outcrop occurs on 5 to 15 percent of this

landscape component. The dominant potential natural vegetation is subalpine

fir and whitebark pine series. This component represents 60 percent of this

unit.

Rockland occurs on a variety of non-carbonate rocks. This component is a

miscellaneous landtype and is classified as a scree habitat type. It does

support some alpine fir and whitebark pine. This component represents 25

percent of this LTA.

Compiled by: Richard Saunders and Robin Strathy, Lewis and Clark National

Forest, and Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 213
LTA50-M332D

GLACIATED MOUNTAIN SLOPES: METASEDIMENTARY (BELT)

Location: This unit is located in the Big Belt Mountains of the Upper

Missouri River basin of west central Montana.

 Acreage by Section

 50-M332D 5,840

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs on gently to moderately

sloping glacial landscape settings. Parent materials are undifferentiated

glacial drift composed of argillites, siltites and quartzites. Small areas of

residual materials and rock outcrop are also included. They are medium

textured.

Accessory Characteristics: The primary soils are deep, moderately coarse to

medium textured. The vegetation is, typically, a mosaic of coniferous forest

with some wetlands. Mean annual precipitation ranges from 50 to 88 centimeters

(20 to 35 inches). The elevation range of this unit is 1846 to 2461 meters

(6000 to 8000 feet). The dominant slopes range from 10 to 40 percent. This map

unit is slightly dissected by streams, with the dominant stream patterns being

deranged and dendritic. Wetlands, seeps, bogs and riparian zones are common

components of this unit.

LTA Components: This landtype association consists of gently to moderately

sloping glacial moraines and glaciated mountain slopes.

Gently to moderately sloping glacial moraines are formed in the

undifferentiated belt materials, both till and outwash. The moderately sloping

glaciated mountain topography is covered with till. These areas have slopes

that range from 10 to 40 percent. They have moderately coarse to medium

textured materials. The major soils are classified as Typic Cryochrepts and

Typic Cryoboralfs. They often have volcanic ash influence at higher

elevations. The dominant potential natural vegetation is subalpine fir and

Douglas-fir.

Compiled by: Larry Laing, Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 214
LTA51-M332Dh

LTA51-M332Dj

GLACIATED MOUNTAIN SLOPES: GRANITICS

Location: This LTA is located in the Boulder, Big Belt, and Elkhorn

Mountains; Beverhead-Deerlodge and Helena National Forests, southwest Montana,

in the upper Jefferson and Missouri River Basins.

 Acreage by Subsection

 51-M332Dh 10,705

 51-M332Dj 45,854

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a glaciated mountain

landscape setting, which is typically composed of glaciated mountain slopes,

ridges, and moraines. Parent materials are residuum and granitic glacial

moraine underlain by weathered granitic bedrock. The surface mineral horizon

is often influenced by wind blown volcanic ash.

Accessory Characteristics: The primary soils are shallow, moderately deep,

and deep with gravelly, cobbly and bouldery; sandy and loamy textures. The

vegetation is a mosaic of meadows and coniferous forest. Mean annual

precipitation ranges from 41 to 76 centimeters (16 to 30 inches). The

elevation range of this LTA is 1678 to 2591 meters (5500 to 8500 feet). The

dominant slopes have gradients of 20 to 50 percent. This LTA is highly

dissected by streams. The dominant stream pattern is rectangular with a

deranged pattern locally in glacial moraines. Wetlands are a major component

of this LTA.

LTA Components: This landtype association consists of glaciated mountain

slopes and ridges, and glacial moraines.

Glaciated mountain slopes and ridges are formed in weathered granitic bedrock.

Slope gradients range from 10 to 50 percent. Soils on these landforms are

shallow and moderately deep, weakly developed, with gravelly sandy and loamy

textures. These soils are classified as Typic and Lithic Cryochrepts and

Cryorthents with local areas of Typic Cryoboralfs. Rock outcrop occurs on

about 25 percent of this landscape component. The dominant potential natural

vegetation is subalpine fir series. This component represents 50 percent of

this LTA.

Moraines are formed in granitic glacial deposits. Slope gradients range from

0 to 35 percent. Soils on these landforms are deep, moderately developed, with

cobbly and bouldery loamy textures. Some areas have a surface mineral layer

with wind blown volcanic ash influence. These soils are classified as Typic

and Aquic Cryochrepts and Cryoboralfs. Rock outcrop is not associated with

this landscape component. The dominant potential natural vegetation is

Douglas-fir and subalpine fir series. Small meadows scattered throughout the

area contain Typic and Aquic Cryoborolls, and Typic Cryaquolls with willow,

sedge and hairgrass series. The moraine component represents 50 percent of

this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest and Larry

Laing, Helena National Forest.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 215
LTA51-M332D

LTA51-M332E

LTA51-M331A

GLACIATED MOUNTAIN SLOPES: HARD INTRUSIVE ROCKS

Location: This unit is located in the Gallatin, Madison, Crazy and

Absaroka-Beartooth mountain ranges in southwestern Montana.

 Acreage by Section

 51-M332D 42,250 (Section except M332Dh,M332Dj)

 51-M332E 125,884

 51-M331A 760

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit consists of gently to

moderately steep glacial moraine. Soil parent material is glacial till

derived from coarse grained, shallow intrusive rocks.

Accessory Characteristics: Vegetation is sparse to dense upper to lower

subalpine forest, Douglas-fir forest, or mountain grassland. Elevation ranges

from 1981 to 2743 meters (6500 to 9000 feet). Mean annual precipitation is

from 50 to over 125 centimeters (20 to greater than 50 inches). Slope

gradient ranges from 0 to 40 percent.

LTA Components: This landtype association consists of three components.

Where vegetation is grassland, soils are Typic Cryoborolls and Argic

Cryoborolls. These soils are deep, moderately coarse to medium textured,

rocky, and have moderate fertility and water holding capacity. Rock outcrop

makes up five percent of this component. Common potential natural vegetation

is big sagebrush and Douglas-fir series. This component makes up 15 percent of

the LTA.

Where vegetation is lower subalpine forest with some Douglas-fir forest, soils

are Typic Cryochrepts. These soils are moderately coarse texture, rock, and

have low fertility and water holding capacity. Rock outcrop makes up 10

percent of this component. Common potential natural vegetation is subalpine

fir with some Douglas-fir. This component makes up 50 percent of the LTA.

Where vegetation is upper subalpine forest, soils are Cryochrepts intermixed

with some Cryumbrepts. These soils are deep to moderately shallow, rocky, and

have low fertility and water holding capacity. Rock outcrop makes up 20 to 40

percent of this component. Common potential natural vegetation includes

subalpine fir, spruce and Idaho fescue series. This component makes up 35

percent of the LTA.

Compiled by: Henry Shovic, Gallatin National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 216
LTA53-M332D

LTA53-M332C

GLACIATED MOUNTAIN SLOPES: SANDSTONES AND SHALES

Location: This LTA is located throughout the Lewis and Clark Forest.

 Acreage by Section

 53-M332D 10,191

 53-M332C 165,005

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs on an alpine glacial till

landform which is typically composed of outwash benches, drift plastered

trough walls, and hilly valley bottoms. Parent materials are sandstones and

shales.

Accessory Characteristics: The primary soils are deep, very cobbly loams. The

vegetation is subalpine forest. Mean annual precipitation ranges from 63 to 88

centimeters (25 to 35 inches). The elevation range of this LTA is 1524 to 1981

meters (5000 to 6500 feet). The dominant slopes have gradients of 10 to 40

percent. This landtype is moderately dissected by streams with the dominant

stream pattern being parallel. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of clayey glacial drift

deposits, drift plastered trough walls, hilly valley bottoms, and hilly

glaciated valleys.

The clayey glacial drift deposits are formed mainly in sandstone and shale

material. Slope gradients range from 25 to 40 percent. The soils on these

landforms are deep, weakly developed, loamy-skeletal loams. These soils are

classified as Typic Cryochrepts. Rock outcrop occurs on about 10 percent of

this landscape. The dominant potential natural vegetation series is subalpine

fir.

The drift plastered trough walls are formed mainly in sandstone and shale

material. Slope gradients range from 25 to 40 percent. The soils on these

landforms are deep, weakly developed, and loamy-skeletal. These soils are

classified as Typic Cryochrepts. Rock outcrop occurs on about 10 percent of

this landscape. The dominant potential natural vegetation series is

Douglas-fir.

The hilly valley bottoms are formed mainly in sandstone and shale. Slope

gradients range from 10 to 25 percent. The soils on these landforms are

moderately deep, weakly developed, and loamy-skeletal. These soils are

classified as Andic Cryochrepts. Rock outcrop occurs on about 15 percent of

this landscape. The dominant natural vegetation series is Douglas-fir.

The hilly glaciated valleys are formed mainly in sandstone and shale. Slope

gradients range from 10 to 25 percent. The soils on these landforms are

moderately deep, weakly developed, clay loams with 35 to 50 percent gravel.

These soils are classified as Argic Cryoborolls. Rock outcrop occurs on less

than 5 percent of this LTA. The dominant natural vegetation series is rough

fescue.

Compiled by: Richard Saunders, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 217
LTA54-M332D

LTA54-M332E

GLACIATED MOUNTAIN SLOPES: VOLCANICS

Location: This LTA is located in southwest Montana in the Boulder Mountains

in the upper Jefferson River and upper Clark Fork River basins. It occurs on

the Beaverhead-Deerlodge National Forest and the Helena National Forest.

 Acreage by Subsection

 54-M332D 45,449 

 54-M332E 31,160

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a glaciated mountain

landscape setting, which is typically composed of glaciated mountain slopes

and moraines. Parent materials are glacial deposits and residuum underlain by

volcanic bedrock.

Accessory Characteristics: The primary soils range from very deep to shallow

to bedrock. They are loamy with high cobble contents especially in the

subsurface layers. The vegetation is a mosaic of coniferous forest and wet

meadows with the forest dominating. Mean annual precipitation ranges from 41

to 76 centimeters (16 to 30 inches). The elevation range of this LTA is 1677

to 2591 meters (5500 to 8500 feet). The dominant slopes have gradients of 10

to 50 percent. This LTA is highly dissected by streams, with the dominant

stream patterns being parallel or dendritic on sideslopes with a deranged

pattern locally in glacial moraines. Wetlands are a major component of this

LTA.

LTA Components: This landtype association consists of moraines and glaciated

mountain slopes.

Moraines are formed in volcanic glacial deposits. Volcanic ash effected loess

deposits often influence surface soil characteristics. Slope gradients range

from 0 to 35 percent. Soils on these landforms are very deep, moderately

developed, with cobbly loam, very cobbly loam and clay loam surface textures.

Very cobbly loams typify subsurface textures. These soils are classified as

Typic and Aquic Cryochrepts and Cryoboralfs. Rock outcrop does not occur in

this landscape component. The dominant potential natural vegetation is

Douglas-fir and subalpine fir series. Meadows in this component have soils

classified as Typic and Aquic Cryoborolls, and Typic Cryaquolls with willow,

sedge, and tufted hairgrass series. This component represents 70 percent of

this LTA.

Glaciated mountain slopes are formed in volcanic bedrock. Volcanic ash

affected loess deposits often influence surface soil characteristics. Slope

gradients range from 20 to 50 percent. Soils on these landforms are typically

shallow to moderately deep, weakly to moderately developed with cobbly loam or

loam surface textures. The subsurface layers are very or extremely cobbly

loams. These soils are classified as Typic and Lithic Cryochrepts and Typic

Cryoboralfs. Rock outcrop occurs on about 20 percent of this landscape

component. The dominant potential natural vegetation is subalpine fir series.

This component represents 30 percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest; Larry Laing,

Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 218
LTA57-M332D

LTA57-M331A

GLACIATED MOUNTAIN SLOPES: GNEISSES AND SCHISTS

Location: This LTA is located mostly in the Beartooth Mountains of southwest

Montana. A very small acreage occurs in the Bridger Range.

 Acreage by Section

 

 57-M332D 569

 57-M331A 177,582

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a glaciated mountain

landscape setting, which is typically composed of moraines. Parent materials

are very bouldery glacial till underlain by gneiss and schist bedrock. In the

Bridger Range this unit consists mostly of weakly metamorphosed granite.

Accessory Characteristics: The primary soils are deep, with very bouldery

medium to moderately coarse textures. The vegetation is a mosaic of coniferous

forest. Mean annual precipitation ranges from 55 to 114 cms. (22 to 50 inches).

The elevation range is 1675 to 2743 meters (5500 to 9000 feet). The dominant

slopes have gradients of 0 to 80 percent.

LTA Components: This landtype association consists of ground moraines in

grassland, ground moraine in forest, and lateral moraines.

Ground moraines are formed in glacial till developed from gneiss and schist

material. Slope gradients range from 5 to 20 percent. Forested soils on these

landforms are shallow to deep, weakly developed, and very bouldery medium to

moderately coarse textured. These soils are classified as Typic Cryumbrepts,

Typic Cryochrepts, Typic Cryofluvents, and Lithic Cryorthents. The dominant

potential natural vegetation is Douglas-fir, limber pine and subalpine fir.

This component represents 70 percent of this unit.

Ground moraines in grassland are formed in glacial till developed from gneiss

and schist with some probable addition of loess. Soils are Typic Cryoborolls,

and Argic Cryoborolls. They are moderately coarse to medium textured, deep,

and moderately fertile. The dominant potential natural vegetation is Idaho

fescue and bluebunch wheatgrass. Rock outcrop makes up 5 percent of the unit.

This component represents 15 percent of this unit.

Lateral moraines are formed in glacial till developed from gneiss and schist

material. Slope gradients range from 50 to 80 percent. Soils on these

landforms are shallow to deep, moderately developed, medium and moderately

fine textured. These soils are classified as Typic Cryoborolls, Typic

Cryochrepts, and Typic Cryoboralfs. Rock outcrop occurs on about 10 percent of

this landscape component. The dominant potential natural vegetation is

Douglas-fir and subalpine fir. This component represents 15 percent of this

unit.

Compiled by: John R. Lane, Custer National Forest and Henry Shovic, Gallatin

National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 219
LTA60-M332D

MOUNTAIN SLOPES AND RIDGES: METASEDIMENTARY (BELT)

Location: This LTA is located in the Big Belt and Elkhorn Mountains and the

Nevada-Alice Range within the Missouri River Basin.

 Acreage by Section

 

 60-M332D 310,782

LTA Settings and General Characteristics

Differentiating Characteristics: This LTA occurs in a mountainous landscape

setting, which is typically composed of mountain ridges, mountain slopes,

structural benches and rolling uplands. Parent materials are residuum and

colluvium underlain by argillite, siltite and quartzite with sandstone, shale

and andesitic dikes and sills in places. Belt rocks within this section tend

to be weakly metamorphosed and relatively thin bedded. They are often

shale-like in appearance.

Accessory Characteristics: The primary soils are shallow, moderately deep and

deep and are medium textured. The vegetation is a mosaic of coniferous

forest, shrublands and mountain grasslands. Mean annual precipitation ranges

from 25 to 75 centimeters (10 to 30 inches). The elevation range of this LTA

is 1068 to 2288 meters (3500 to 7500 feet). The dominant slopes have gradients

of 10 to 60 percent. This LTA is highly to slightly dissected (widely to

closely spaced drainages) by streams within the rolling upland, structural

bench and mountain slope components of this LTA. The rolling uplands and

structural benches tend to be moderately incised whereas the mountain slopes

are deeply incised by streams. The dominant stream pattern is dendritic. The

mountain ridge component of this LTA is undissected.

LTA Components: This landtype association consists of mountain slopes,

mountain ridges, structural benches, and rolling uplands.

Mountain slopes are formed in colluvium and residuum mostly derived from

argillite and siltite with sandstones, shales, and andesitic dikes and sills

in places. Slope gradients range from 25 to 60 percent. Soils on these

landforms are mostly deep and very deep. They tend to have moderate subsoil

clay accumulation, particularly on the moderate slopes. The weakly

metamorphosed zone within this section tends to have soils dominated by

gravelly and channery rock fragments. They typically have gravelly, very

gravelly, extremely gravelly, channery, very channery or extremely channery

silt loam, loam or sandy loam surface textures in forested areas. Cobbles or

flaggy material sometimes dominate in the more metamorphosed and thickly

bedded Belts in parts of subsection M332Di. They are shallow and moderately

deep, have modest development (dark surface layers and moderate clay subsoil

accumulation where the soils are deeper), and have loam surfaces on grassland

and shrubland potential sites. Subsurface textures (in both forested and

non-forested settings) include mostly very to extremely gravelly and channery

loams, clay loams and sandy loams. Some cobbly or flaggy material is

associated with the more thickly bedded Belt rocks near the Continental Divide

in subsection M332Di. Forested soils on moderate slopes are typically

classified as Typic and Mollic Cryoboralfs. The steeper slopes are often more

weakly developed Typic and Lithic Ustochrepts and Typic Cryochrepts. Lithic

and Argic Cryoborolls and Typic Haploborolls are associated with

grassland/shrubland potential sites. Rock outcrop occurs on about 5 percent of

this landscape component. The dominant potential natural vegetation is

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 220
subalpine fir and Douglas-fir series. Grassland/shrubland series include Idaho

fescue, big sagebrush, and rough fescue. This component represents 60 percent

of this LTA.

Mountain ridges are formed in residuum mostly derived from argillite and

siltite with sandstone and shales in places. Thin volcanic ash influenced

loess deposits affect the surface soils at higher elevations. Slope gradients

range from 10 to 40 percent. Grassland or shrubland soils on these landforms

are shallow and moderately deep, are moderately developed (thick dark surface

layers and subsoil clay accumulation where soils are deeper), and have loam or

channery loam surface textures. Forested soils are moderately deep and deep,

are weakly or moderately developed and have loam, channery loam, channery silt

loam. Subsurface textures for both forested and non-forested potential sites

include very channery and extremely channery loams. Very cobbly and extremely

cobbly loams and (in association with quartzite bedrock) extremely cobbly

sandy loam can occur in some areas within the more metamorphosed Belts in

subsection M332Di. These soils are classified as Lithic and Argic

Cryoborolls, Mollic Cryoboralfs and Typic Cryochrepts. Rock outcrop occurs on

about 5 percent of this landscape component. The dominant potential natural

vegetation is rough fescue, Idaho fescue, big sagebrush, limber pine,

Douglas-fir and subalpine fir series. This component represents 30 percent of

this LTA.

Structural benches are formed in colluvium and residuum derived from argillite

and siltite with sandstone and shale in places. Slope gradients range from 10

to 30 percent with inclusions of short 40 to 60 percent slopes near some

drainages. Soils on these landforms are shallow and moderately deep and

weakly developed at lower elevations. They are deep or very deep and better

developed at higher elevations. Surface textures are mostly very gravelly or

channery loam or extremely gravelly loam. Subsurface layers can have very to 

extremely gravelly or channery loam textures. Some very or extremely cobbly

loams or clay loams can occur, particularly in the more metamorphosed zones in

subsection M332Di. These soils are classified as Lithic and Typic Ustochrepts

at lower elevations and Typic Cryoboralfs and Typic Cryochrepts at higher

elevations. Rock outcrop occurs on about 5 percent of this landform. The

dominant potential natural vegetation includes Idaho fescue and bluebunch

wheatgrass series. Forested habitat types at low elevations include

Douglas-fir and ponderosa pine in some drainages and on some north aspects.

Subalpine fir and Douglas-fir series dominate at higher elevations. Tufted

hairgrass series occurs in depressions at higher elevations. This component

represents 8 percent of this LTA.

Rolling uplands are formed in residuum and colluvium derived from argillite

and siltite with sandstone, shale and basalt in places. Slope gradients range

from 10 to 25 percent. Soils on these landforms are shallow and moderately

developed (dark surface layers). They have silt loam and sandy clay loam

surface textures. Subsurface layers tend to be very stony sandy clay loam.

These soils are classified as Lithic Argiborolls . Rock outcrop occurs on

about 5 percent of this landscape component. The dominant potential natural

vegetation is Idaho fescue and bluebunch wheatgrass series. This inclusion

represents 2 percent of this LTA.

Compiled by: Larry Laing, Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 221
LTA61-M332D

LTA61-M332E

MOUNTAIN SLOPES AND RIDGES: HIGHLY WEATHERED GRANITICS

Location: This LTA is located in the Boulder, Elkhorn and Highland Mountains

on the Beaverhead-Deerlodge National Forest and the Helena National Forest in

southwest Montana. It occurs in the upper Jefferson River, Prickly Pear Creek,

10 Mile Creek and Clark Fork River Basins.

 Acreage by Subsection

 61-M332D 251,536

 61-M332E 308,903

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of stream dissected mountain slopes,

rolling uplands and alluvial flats. Parent materials are residuum underlain by

weathered granitic bedrock.

Accessory Characteristics: The primary soils are shallow to deep with

gravelly sandy and loamy textures. The vegetation is a mosaic of shrublands

and grasslands and coniferous forest. Small areas of aspen are common. Mean

annual precipitation ranges from 30 to 76 centimeters (12 to 30 inches). The

elevation range of this LTA is 1373 to 2591 meters (4500 to 8500 feet). The

dominant slopes have gradients of 10 to 50 percent. This LTA is moderately or

highly dissected by streams, with the dominant stream pattern being dendritic.

Wetlands are a major component in this LTA on the Deerlodge National Forest.

LTA Components: This landtype association consists of stream dissected

mountain slopes, rolling uplands, and alluvial flats.

Stream dissected mountain slopes are formed in weathered granitic bedrock.

Slope gradients range from 10 to 50 percent. Soils on these landforms are

shallow and moderately deep, weakly and moderately developed, with gravelly

sandy and loamy textures. These soils are classified as Typic and Lithic

Cryoborolls, Cryochrepts, Cryoboralfs, and Cryorthents. Rock outcrop occurs on

about 20 percent of this landscape component. The dominant potential natural

vegetation is sagebrush, Idaho fescue, Douglas-fir and subalpine fir series.

This component represents 55 percent of this LTA.

Rolling uplands are formed in moderately and weakly weathered granitics

granite-diorites and diorites. Slope gradients range from 10 to 40 percent.

Soils on these landforms are moderately deep and deep, are weakly and

moderately developed, and have sandy loam, gravelly sandy loam and loamy sand

surface soils. The subsurface layers are gravelly sandy loams, gravelly loamy

sands and loamy sands in the less developed soils and gravelly sandy clay

loams and sandy clay loams where subsoil clay accumulation occurs. 

Ustochrepts, Eutroboralfs and Haploborolls prevail at the lower elevations. 

Typic and Lithic Cryoboralfs and Cryoborolls dominate at the mid to high

elevations. Rock outcrop occurs on about 5 percent of this landscape

component. Boulders are scattered on the surface on parts of the unit. The

dominant potential natural vegetation is Douglas-fir series. The

grassland/shrublands are dominated by mountain big sagebrush and rough fescue

series. Spruce dominates the wet forest inclusions. This component represents

35 percent of this LTA.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 222
Alluvial flats are formed in weathered granitic bedrock. Slope gradients range

from 0 to 15 percent. Soils on these landforms are deep, weakly developed,

with gravelly loamy textures. These soils are classified as Oxyaquic and Typic

Cryochrepts and Cryoborolls. Rock outcrop does not occur on this landscape

component. The dominant potential natural vegetation is willow, sedge, spruce,

and subalpine fir series. This component represents 10 percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest; Larry Laing,

Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 223
LTA62-M332D

LTA62-M332E

MOUNTAIN SLOPES AND RIDGES: WEAKLY WEATHERED GRANITICS

Location: This LTA is located in the Ten Mile Creek basin, the Elkhorn

Mountains, the Big Belt Mountains, and the Continental Divide Uplands.

 Acreage by Section

 62-M332D 88,948

 62-M332E 949

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountainous landscape

setting, which is typically composed of mountain slopes and ridges. Parent

materials are residuum and colluvium underlain by granite, granitic diorite

and diorite.

Accessory Characteristics: The primary soils have medium or moderately coarse

textured surfaces and moderately coarse and coarse textured subsurface layers.

The vegetation is a mosaic of coniferous forest and forested scree. Mean

annual precipitation ranges from 50 to 75 centimeters (20 to 30 inches). The

elevation range of this LTA is 1554 to 2438 meters (5100 to 8000 feet). The

dominant slopes have gradients of 10 to 60 percent. This LTA is primarily

undissected.

LTA Components: This landtype association consists of mountain slopes and

ridges.

Mountain slopes and ridges are formed in weakly weathered granites,

granite-diorites, and diorites. Higher elevations can have volcanic ash

influenced surface soil. Slope gradients range from 10 to 60 percent. Soils

on these landforms are extremely variable in terms of depth to bedrock,

display little to no soil development and have cobbly loam, extremely cobbly

sandy loam and extremely bouldery sand surface soils. Subsurface soils vary

also and include extremely cobbly sandy loam, very cobbly sandy loam and

extremely bouldery sand textures. These soils are mostly classified as Typic

Cryochrepts and Typic Cryorthents. Boulders are scattered about the surface

in portions of the unit. Rock outcrop and scree occurs on about 45 percent of

this landscape component. The dominant potential natural vegetation is

subalpine fir-whitebark pine series at the higher elevations with subalpine

fir and Douglas-fir series on the lower slopes. This component represents 100

percent of this LTA.

Compiled by: Larry Laing, Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 224
LTA63-M332D

MOUNTAIN SLOPES AND RIDGES:

SCHISTS, GNEISSES AND ASSOCIATED METAMORPHICS

Location: This LTA occurs mainly in the Little Belt, Crazy and Castle

mountains. This unit includes high elevation ridges within the Big Belts

Mountains.

 Acreage by Section

 

 63-M332D 149,345

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs on ridges and steep valley

sideslopes. Parent materials are gneiss, sandstone, shale and granite.

Accessory Characteristics: The primary soils are moderately deep skeletal

loams and sandy loams. The vegetation is mostly grassland with some forested

areas. Mountain ridgetop alpine meadows dominate in the Big Belt Mountains.

Mean annual precipitation ranges from 50 to 100 centimeters (20 to 40 inches).

The elevation range of this LTA is 1524 to 2134 meters (5000 to 7000 feet) on

the Lewis and Clark National Forest and 2440 to 2898 meters (8000 to 9500

feet) on the Helena National Forest. The dominant slopes have gradients of 25

to 60 percent. This LTA is moderately dissected by streams, with the dominant

stream pattern being dendritic. Mountain ridges are often undissected.

LTA Components: This landtype association consists of steep valley sideslopes,

and ridges and lower valley slopes.

The steep valley sideslopes are formed in sandstone, basalt, and gneiss. Slope

gradients range from 25 to 60 percent. Soils on these landforms are moderately

deep, weakly developed, extremely cobbly sandy-loams. These soils are

classified as Typic Cryoboralfs and Typic Cryochrepts. Mollisolls are

scattered throughout the Little Belts and Highwood Mountains. The dominant

potential natural vegetation is a mosaic of subalpine fir and rough fescue. 

This component represents 35 percent of this LTA.

The ridges and lower valley slopes are formed in sandstone and shale. Slope

gradients are 10 to 40 percent. Soils on these landforms are deep to

moderately deep and moderately well developed. They have loam surfaces and

clay loam or clay subsoils These soils are classified as Boralfic Cryoborolls

and Aquic Cryoboralfs. Typic Cryumbrepts dominate in the Big Belts Mountains.

 They are mostly moderately deep with sandy loam surfaces and very gravelly

sandy loam subsurface layers. The dominant potential natural vegetation is

rough fescue and subalpine fir series on the Lewis and Clark National Forest

and Idaho fescue series in the Big Belt Mountains. This component represents

50 percent of this LTA. Small wetlands occur within this unit.

Compiled by: Richard Saunders, Lewis and Clark National Forest

Revised by Larry Laing, Helena/Lewis and Clark National Forests.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 225
LTA64-M332Db

LTA64-331D

MOUNTAIN SLOPES AND RIDGES: VOLCANICS

Location: This LTA is located mostly in the Highwood and Castle mountain

ranges in central Montana in the Missouri River Basin. Smaller amounts occur

in the Little Belt, Snowy and Judith Mountains subsection.

 Acreage by Subsection

 64-M332Db 3,240

 64-331D 26,813

LTA Setting and General Characteristics: 

Differentiating Characteristics: This LTA occurs in a mountain slope

landscape setting, which is typically composed of moderately steep to steep

mountain slopes and valley sideslopes. Parent materials are latite, rhyolites,

and shonkinites. 

Accessory Characteristics: The primary soils are well drained, 20 to 60

inches in depth, slightly acidic to neutral and loamy skeletal. Vegetation is

a complex of grassland and lodgepole pine forest. Mean annual precipitation

ranges from 51 to 76 centimeters (20 to 30 inches). The elevation range of

this LTA is 1371 to 1982 meters (4500 to 6500 feet). The dominant slopes have

gradients of 25 to 60 percent. This LTA is well dissected by streams, with the

dominant stream pattern being subparallel. Wetlands are a minor component of

this LTA.

LTA Components: This landtype association consists of stream dissected

mountain slopes.

Stream dissected mountain slopes are formed in colluvium derived from

rhyolite, latite, and shonkinite parent materials. Slope gradients range from

25 to 60 percent. Soils on these landforms are weakly developed, 20 to 60

inches in depth; loam topsoils are 4 to 10 inches thick, subsoils are brown

loam with 10 to 75 percent cobble. These soils are classified as Typic

Cryochrepts. Rock outcrop occurs on about 10 percent of this landscape

component. The dominant potential natural vegetation is Douglas-fir at lower

elevations, and subalpine fir at higher elevations. 

Compiled by: Robin Strathy, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 226
LTA64-M332De

LTA64-M332Be

LTA64-M332Bk

MOUNTAIN SLOPES AND RIDGES: VOLCANICS

Location: This LTA is located in the Sapphire and Boulder Mountains on the

Beaverhead-Deerlodge and Helena National Forests in the upper Clark Fork River

Basin in southwest Montana. It also occurs along the Continental Divide in

the Alice-Nevada Mountains.

 Acreage by Subsection

 64-M332De 6,116

 64-M332Be 12,963

 64-M332Bk 7,098

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a mountainous landscape

setting, which is typically composed of mountain slopes and ridges. Parent

materials are residuum and colluvium underlain by rhyolite and tuff. Ridges

often have ash influenced soil surfaces.

Accessory Characteristics: The primary soils have medium textured to

moderately coarse textured surfaces and moderately coarse to coarse textured

subsurface layers. The vegetation is coniferous forest. Mean annual

precipitation ranges from 50 to 75 centimeters (20 to 30 inches). The

elevation range of this LTA is 1676 to 2195 centimeters (5500 to 7200 feet).

The dominant slopes have gradients of 10 to 60 percent. The mountain slopes

within this LTA are poorly dissected by weakly incised streams. Ridges are

mostly undissected.

LTA Components: This landtype association consists of mountain slopes and

ridges.

Mountain slopes and ridges are formed in rhyolites and tuffs. Slope gradients

range from 10 to 60 percent. Soils on these landforms are moderately deep and

weakly developed. Surface textures range from very gravelly sandy loam on

steeper slopes to loams on volcanic ash influenced ridges. Subsurface textures

are often very cobbly coarse sandy loam or extremely cobbly loamy sand. These

soils are classified as Dystric Cryochrepts and Andic Cryochrepts. Rock

outcrop occurs on about 5 percent of this landscape component. The dominant

potential natural vegetation is subalpine fir. Small areas of subalpine

fir-whitebark pine series occur at high elevations. This component represents

100 percent of this LTA.

Compiled by: Larry Laing, Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 227
LTA64-M332D

LTA64-M332E

LTA64-M331A

MOUNTAIN SLOPES AND RIDGES: VOLCANICS

Location: This LTA is located in the Boulder, Elkhorn, Fleecer, Anaconda,

Pintlar, Beaverhead, Madison, Pioneer, Lima Peaks, Gravelly, Tendoy, and

Gallatin Mountains on the Beaverhead-Deerlodge, Helena, and Gallatin National

Forests. It occurs in the upper Missouri River Basin and the upper Little

Blackfoot drainage in southwest Montana.

 Acreage by Section

 M332D 190,576 (Section except for M332Db and M332De)

 M332E 216,157

 M331A 21,407

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of stream dissected mountain slopes and

mountain ridges. Parent materials are residuum underlain by Tertiary and

Cretaceous volcanic bedrock, including andesite, dacite, rhyolite, welded and

non-welded rhyolite and felsic tuffs, and locally basalt and minor metagrabbro

dikes.

Accessory Characteristics: The primary soils are shallow, moderately deep and

deep loamy soils often with high cobble contents. The vegetation is a mosaic

of coniferous forest and shrubland/grassland, coniferous forest or shrubland

/grassland. Mean annual precipitation ranges from 38 to 75 centimeters (15 to

30 inches). The elevation range of this LTA is 1525 to 2378 meters (5000 to

7800 feet). The dominant slopes have gradients of 5 to 60 percent. The

mountain slopes component of this LTA are moderately dissected by streams with

the dominant stream patterns being parallel or dendritic. The mountain ridges

are generally undissected. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of stream dissected

mountain slopes, and mountain ridges.

Stream dissected mountain slopes are formed in colluvium and residuum over a

variety of volcanic bedrock. Some high elevation areas are influenced by

volcanic ash loess deposits. Slope gradients range from 25 to 60 percent.

Soils on these landforms are shallow, moderately deep and deep to bedrock.

They are moderately and weakly developed with cobbly and very cobbly loam

surface textures. The subsurface layers are very cobbly and extremely cobbly

loams. These soils are classified as Typic and Lithic Cryochrepts and

Cryoborolls, and Typic and Mollic Cryoboralfs. Rock outcrop occurs on about 10

percent of this landscape component. The dominant potential natural vegetation

is Douglas-fir and subalpine fir series. This component represents 50 percent

of this LTA.

Mountain ridges are formed in residuum and colluvium over a variety of

volcanic bedrock. Some high elevation areas are influenced by volcanic ash

loess deposits. Included in this component is rolling uplands found in the

eastern portion of the Elkhorns. Slope gradients range from 10 to 40 percent.

Soils on these landforms are mostly moderately deep and shallow to bedrock. 

They are moderately and weakly developed with cobbly, stony and very cobbly

loam or loam surface textures. The subsurface layers are verycobbly, very

stony, extremely cobbly and extremely stony loams and clay loams. These soils

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 228
are mostly classified as Typic and Lithic Cryochrepts on forested sites and

Argic and Lithic Cryoborolls on grassland/shrublands. Rock outcrop occurs on

about 10 percent of this landscape component. The dominant potential natural

vegetation is rough fescue, big sagebrush, Douglas-fir, and subalpine fir

series. This component represents 50 percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest; Larry Laing,

Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 229
LTA65-M332D

LTA65-M332E

MOUNTAIN SLOPES AND RIDGES: SOFT SEDIMENTARY ROCKS

Location: This LTA is located in nearly all the mountain ranges on the Lewis

and Clark (Rocky Mountain Front, Big & Little Snowies, Crazies, Castles, and

Little Belt mountains). It also occurs in the Fleecer and Bull Mountains in

southwest Montana on the Beaverhead-Deerlodge Forest.

 Acreage by Section

 65-M332D 42,266

 65-M332E 17,413

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs on benches, basins, ridges,

and valley sideslopes. Parent materials are soft sandstones and shales.

Accessory Characteristics: The primary soils are shallow, moderately deep and

deep, skeletal, loams and sandy loams. The vegetation is coniferous forest and

fescue grassland. Mean annual precipitation ranges from 41 to 76 centimeters

(16 to 30 inches). The elevation range of this LTA is 1500 to 2439 meters

(5000 to 8000 feet). The dominant slopes have gradients of 10 to 60 percent. 

This LTA is moderately dissected with the dominant stream pattern being

dendritic. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of benches and lower

valley slopes, steep valley sideslopes, and ridges and upland flats and

basins.

Benches and lower valley slopes are formed in shale, sandstone, and alluvium.

These landforms have slope gradients that range from 0 to 25 percent. Soils on

these landforms are moderately deep and deep, well developed, and consist

mainly of clay loam and clay. The major soils are classified as Typic and

Vertic Cryoborolls. Rock outcrop occurs on 5 percent of this landscape

component. The dominant potential natural vegetation is rough fescue and

Douglas-fir. This component represents 30 percent of this LTA.

Steep valley sideslopes are formed in shale and sandstone. These landforms

have slope gradients that range from 25 to 60 percent. Soils on these

landforms are moderately deep, weakly developed, and consist mainly of very

gravelly and cobbly loams and sandy loams. The major soils are classified as

Typic Cryoborolls and Cryoboralfs. Rock outcrop makes up less than 15 percent

of this component. The dominant potential natural vegetation is rough fescue

subalpine fir, Douglas-fir, and limber pine. This component represents 35

percent of this LTA.

Ridges and upper slopes and basins are formed in sandstone and shale. These

landforms have slope gradients that range from 10 to 40 percent. Soils on

these landforms are extremely cobbly loams and sandy loams. The major soils

are classified as Typic and Andic Cryoborolls and Cryochrepts. Rock outcrop

makes up less than 15 percent of this LTA. The dominant potential natural

vegetation is Douglas-fir and rough fescue. This component represents 20

percent of this LTA.

Compiled by: Richard Saunders, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 230
LTA66-M332Dm

LTA66-M332Ea

MOUNTAIN SLOPES AND RIDGES: CARBONATES

Location: This LTA is located in the Elkhorn and Highland Mountains on the

Beaverhead-Deerlodge National Forest in southwest Montana in the Jefferson

River Basin.

 Acreage by Subsection

 66-M332Dm 19,493

 66-M332Ea 4,501

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of stream dissected mountain slopes.

Parent materials are residuum underlain by limestone bedrock.

Accessory Characteristics: The primary soils are shallow and moderately deep

with cobbly loamy textures. The vegetation is a mosaic of coniferous forest

and shrublands and grasslands. Mean annual precipitation ranges from 36 to 51

centimeters (14 to 20 inches). The elevation range of this LTA is 1677 to 2287

meters (5500 to 7500 feet). The dominant slopes have gradients of 10 to 50

percent. This LTA is moderately dissected by streams, with the dominant stream

pattern being parallel. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of stream dissected

mountain slopes.

Stream dissected mountain slopes are formed in limestone bedrock. Slope

gradients range from 10 to 50 percent. Soils on these landforms are shallow

and moderately deep, moderately developed, and have cobbly loamy textures.

These soils are classified as Typic and Lithic Cryochrepts and Cryoboralfs;

and Argic and Lithic Cryoborolls. Rock outcrop occurs on about 15 percent of

this landscape component. The dominant potential natural vegetation is Idaho

fescue, sagebrush, Douglas-fir and subalpine fir series. This component

represents 100 percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 231
LTA66-M332D

MOUNTAIN SLOPES AND RIDGES: CARBONATES

Location: This LTA is located primarily in the Little Belt, Big Belt and

Elkhorn Mountain Ranges.

 Acreage by Section

 66-M332D 360,264 (Section except M332Dm)

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs on ridgetops, plateaus or

dip slopes, steep valley slopes, and benchy lower valley slopes. Parent

materials are Paleozoic limestones.

Accessory Characteristics: The primary soils are moderately deep,

loamy-skeletal soils with loamy textures. The local vegetation can be

dominantly forest, a mosaic of grassland/shrubland and forest, or grassland

/shrubland. Mean annual precipitation ranges from 50 to 127 centimeters (15 to

50 inches). The elevation range of this LTA ranges from 1068 to 2878 meters

(3500 to 9500 feet). The dominant slopes have gradients of 10 to greater than

60 percent.

LTA Components: This landtype association consists of ridge tops, plateaus and

dip slopes, steep valley sideslopes, and benchy lower sideslopes. All of these

are typically formed in limestone.

Ridgetops typically have slopes of 10 to 25 percent. Soils on these landforms

are moderately deep and weakly to moderately developed. Surface textures are

silt loams or gravelly to very gravelly silt loams or silty clay loams.

Subsurface textures are generally very or extremely gravelly silt loams, clay

loams or silty clay loams. The major soils are classified as Typic Cryochrepts

in the Little Belt Mountains. Calcic Cryoborolls, Mollic Cryoboralfs and

Lithic Cryochrepts dominate in the other subsections. The major potential

natural vegetation is rough fescue, big sagebrush, Douglas-fir, whitebark

pine-subalpine fir and spruce series. Rock outcrop occurs on less than 15

percent of this LTA. This component represents 30 percent of this LTA.

Plateaus or dip slopes are typically on slopes of 10 to 25 percent. Soils on

these landforms are mostly moderately deep or shallow and weakly to moderately

developed. Surface textures are gravelly or very gravelly loams, silty clay

loams or silt loams. The subsurface layers are very or extremely gravelly

loams and silt loams. The major soils are classified as Typic Ustochrepts in

the Little Belts. Lithic Ustochrepts, Calcic Cryoborolls and Mollic

Cryoboralfs dominate in the other subsections. The major potential natural

vegetation is Douglas-fir, ponderosa pine, rough fescue, and big sagebrush

series. Rock outcrop occurs on less than 15 percent of this LTA. This

component represents 20 percent of this LTA.

Steep valley sideslopes are on slopes of 25 to 60 percent. Soils on these

landforms are moderately deep, moderately well developed, Typic Cryochrepts.

The major potential natural vegetation is Douglas-fir and subalpine fir.

Rock-outcrop occurs on less than 15 percent of this LTA. This component

represents 40 percent of this LTA.

Benchy lower sideslopes are on slopes of 10 to 25 percent. Soils on these

landforms are moderately deep and deep, weakly and moderately well developed.

They are mainly Typic Cryoboralfs and Cryoborolls, with considerable acreage

of Vertic Cryoborolls. The major potential natural vegetation is Douglas-fir.

Rock outcrop occurs on less than 15 percent of this LTA. This component

represents 10 percent of this LTA.

Compiled by: Richard Saunders, Lewis and Clark National Forest, and Larry

Laing Helena and Lewis and Clark National Forests.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 232
LTA67-M332D

MOUNTAIN SLOPES AND RIDGES: QUARTZITES

Location: This LTA is located primarily in the Little Belt Mountain Range.

 Acreage by Section

 67-M332D 41,037

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs on ridgetops and hilly valley

floors. Parent material is dominantly quartzite from Cambrian and Precambrian

formations.

Accessory Characteristics: The primary soils are deep, loamy-skeletal, stony

sandy-loams. The vegetation is coniferous forest. Mean annual precipitation is

64 to 76 centimeters (25 to 30 inches). The elevation range is 1981 to 2286

meters (6500 to 7500 feet). The dominant slopes have gradients of 0 to 10

percent.

LTA Components: This landtype association consists of ridge tops and hilly

valley floors.

These ridge tops and hilly valley floors have slopes of 0 to 10 percent. Soils

on these landforms are deep, weakly developed, Typic Cryochrepts. The major

potential natural vegetation series is Douglas-fir. Rock outcrop occurs on

less than 15 percent of this LTA. This component represents the entirety of

this LTA.

Compiled by: Richard Saunders, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 233
LTA68-M332Dm

MOUNTAIN SLOPES AND RIDGES: SANDSTONES AND SHALES

Location: This LTA is located in the Elkhorn Mountains, Beaverhead-Deerlodge

and Helena National Forests in the Jefferson River Basin in southwest Montana.

 Acreage by Subsection

 

 68-M332Dm 14,194

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of stream dissected mountain slopes.

Parent materials are residuum and colluvium underlain by sandstone and shale

bedrock.

Accessory Characteristics: The primary soils are shallow and moderately deep

with gravelly, channery and cobbly loamy textures. The vegetation is a mosaic

of coniferous forest, shrublands, and grasslands. Mean annual precipitation

ranges from 25 to 76 centimeters (10 to 30 inches). The elevation range of

this LTA is 1464 to 2439 meters(4800 to 8000 feet). The dominant slopes have

gradients of 10 to 50 percent. This LTA is moderately dissected by streams

with the dominant stream patterns being parallel and dendritic. Mountain

ridges tend to be undissected. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of stream dissected

mountain slopes.

Stream dissected mountain slopes are formed in sandstone and shale bedrock.

Some areas of mountain ridges and structural benches are included in this

component. Slope gradients range from 10 to 50 percent. Soils on these

landforms are shallow and moderately deep, moderately developed, with

gravelly, channery and cobbly loamy textures. These soils are classified as

Typic and Lithic Cryochrepts, Mollic and Typic Cryoboralfs, Typic

Eutroboralfs, Lithic and Typic Ustochrepts, and Lithic and Argic Cryoborolls.

Rock outcrop occurs on about 10 percent of this landscape component. The

dominant potential natural vegetation is Douglas-fir and subalpine fir series.

Grassland/shrubland series include Idaho fescue, rough fescue, and big

sagebrush. This component represents 100 percent of this LTA.

Compiled by: Dave Ruppert, Deerlodge National Forest; Larry Laing, Helena

National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 234
LTA68-M332Dp

LTA68-M331Aa

LTA68-M331Ap

MOUNTAIN SLOPES AND RIDGES: SANDSTONES AND SHALES

Location: This unit is located in the Bridger, Gallatin, and Madison Mountain

Ranges in southwestern Montana.

 Acreage by Section:

 68-M332Dp 81,951

 68-M331Aa 20,334

 68-M331Ap 79,259

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit consists of a complex of

mountain slopes and ridges, with overall shapes controlled by underlying

bedrock structure. Soil parent material is colluvium and residuum derived

from thinly to thickly interbedded sandstone and shale with some limestone.

Accessory Characteristics: Vegetation is dense lower subalpine forest or

mountain grassland. Elevation ranges from 1981 to 2377 meters (6500 to 7800

feet). Mean annual precipitation is 75 to 100 centimeters (30 to 40 inches).

Slope ranges from 0 to 40 percent.

LTA Components: This landtype association has four components:

Soils in mountain grasslands are Typic Cryoborolls and Argic Cryoborolls. 

They are deep, medium to moderately fine textured, rocky in some areas, and

have moderate to high fertility and water holding capacity. Rock outcrop makes

up 5 percent of this component. Common potential vegetation includes Idaho

fescue and big sagebrush series. This component makes up 20 percent of this

LTA.

Where rock types are thinly inter-bedded sandstone and shale and vegetation is

densely or sparsely forested, soils are Typic and Mollic Cryoboralfs and

Argic Cryoborolls. They are deep, medium textured, rocky, and have moderate

fertility and water holding capacity. Rock outcrop makes of 5 to 20 percent of

this component. Common potential vegetation includes Douglas-fir, subalpine

fir, Idaho fescue and big sagebrush series. This component makes up 40 percent

of this LTA.

Where rock types are thickly inter-bedded sandstone and shale, and vegetation

is densely or sparsely forested, soils are Typic and Mollic Cryoboralfs, Argic

Cryoborolls, and Typic Argiborolls. They are deep, medium to moderately fine

textured, non-rocky, and have high fertility and water holding capacity. Rock

outcrop makes of 5 to 20 percent of this component. Common potential

vegetation includes subalpine fir, subalpine fir-whitebark pine, Douglas-fir,

Idaho fescue and big sagebrush series. This component makes up 20 percent of

this LTA.

Where rock types are limestone, sandstone, and shale, soils are Typic

Ustochrepts, Typic Calciborolls, Cryoboralfs and Cryochrepts. These soils are

deep to moderately shallow, moderately coarse to moderately fine textured,

rocky, and have low to moderate fertility and water holding capacity. Rock

outcrop makes up 15 to 25 percent of this component. Common potential

vegetation includes subalpine fir and Douglas-fir series. This component makes

up 20 percent of this LTA.

Compiled by: Henry Shovic, Gallatin National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 235
LTA68-M332D

LTA68-M332C

LTA68-331D

MOUNTAIN SLOPES AND RIDGES: SANDSTONES AND SHALES

Location: This LTA is located in the Little Belt Mountains and along the Rocky

Mountain Front on the Lewis and Clark National Forest, and in the Elkhorn

Mountains on the Beaverhead-Deerlodge Forest.

 Acreage by Section

 68-M332D 240,099 (Section except for M332Dm and M332Dp)

 68-M332C 80,557

 68-331D 8,549

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a mountain slope or ridge

setting which is typically composed of stream-dissected mountain slopes and

ridges. Parent materials are sandstone and shale.

Accessory Characteristics: The primary soils are moderately deep,

loamy-skeletal loamy-sands and loams. The vegetation is a mosaic of subalpine

fir and rough fescue series. Mean annual precipitation ranges from 36 to 89

centimeters (14 to 35 inches). The elevation range of this LTA is 1524 to 2438

meters (5000 to 8000 feet). This LTA is moderately dissected by streams with

the dominant pattern being parallel. Wetlands are a minor component.

LTA Components: This landtype association consists of low relief ridges and

slopes, and steep valley sideslopes.

The low relief ridges and slopes are formed in sandstone and shale. Slope

gradients are from 10 to 40 percent. Soils on these landforms are moderately

deep to deep, moderately well developed, extremely gravelly loams. These soils

are classified as Typic and Argic Cryoborolls. Rock outcrop occurs on about 5

percent of this landscape component. The dominant potential natural vegetation

is rough fescue and subalpine fir. This component represents 55 percent of

this LTA.

The steep valley sideslopes are formed in sandstone and shale. Slope gradients

are from 40 to 60 percent. The soils are classified as Typic and Andic

Cryochrepts in Subsections M332Cb, M332Cd, M332Dc, and M332Dd; soils in

subsection M332Dm are Cryoboralfs. Rock outcrop occurs on about 10 percent of

this landscape component. The dominant potential natural vegetation is

subalpine fir. This component represents 30 percent of this LTA.

Compiled by: Richard Saunders and Robin Strathy, Lewis and Clark National

Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 236
LTA69-M332D

PEDIMENTS: GRAVEL MANTLED VOLCANICS AND TERTIARY SEDIMENTS

Location: This LTA is located in the foothills near the Bull Mountains and

Elkhorn Mountains in the vicinity of the Beaverhead-Deerlodge National Forest

in southwest Montana. It also occurs in the Boulder River basin in Subsection

M332Dk.

 Acreage by Section

 69-M332D 27,695

LTA Setting and General Characteristics

Differentiating characteristics: This LTA occurs in a valley landscapesetting

which is typically composed of pediments and alluvial fans. Parent materials

are coarse mantle deposits from a variety of sources, deposited over volcanic

and Tertiary sedimentary bedrock.

Accessory Characteristics: The primary soils are shallow and moderately deep,

cobbly and gravelly sandy loams and loams. The vegetation is a mosaic of

grasland and shrubland. Mean annual precipitation ranges from 25 to 36

centimeters (10 to 14 inches). The elevation range of this LTA is from 1372 to

1524 meters (4500 to 5000 feet). The dominant slopes have gradients of 5 to 10

percent. This LTA is moderately dissected by intermittent streams with the

dominant stream patterns being parallel. Wetlands are a minor component of

this unit.

LTA Components: This landtype association consists of two landform components:

pediments and alluvial fans.

Pediments are formed on volcanic and Tertiary sedimentary rocks with a mantle

of coarse debris from the adjoining uplands on the surface. Slope gradients

range from 5 to 10 percent. Soils on these landforms are moderately deep to

deep. They are moderately to weakly developed with cobbly and very cobbly

sandy and loamy surface textures. The subsurface layers are cobbly and very

cobbly loams and clay loams. These soils are classified as Ustochrepts,

Argiborolls and Haploborolls. Rock outcrop occurs on about ten percent of this

landscape component. The dominant potential natural vegetation is needle-andthread grass/blue grama; bluebunch wheatgrass/blue grama, and sagebrush

/bluebunch wheatgrass habitat types. This component represents 60 percent of

this LTA.

Alluvial fans are formed in coarse alluvial and glaciofluvial deposits

originating from a variety of bedrock types. Slope gradients range from 5 to

15 percent. Soils on these landforms are moderately deep to deep; are weakly

to moderately developed, and have cobbly and gravelly sandy loam and loam

surface soils. The subsurface layters are cobbly sandy loams and loams in the

less developed soils and cobbly sandy clay loams and clay loams where subsoil

clay accumulation occurs. These soils are classified as Ustochrepts,

Argiborolls and Haploborolls. Rock outcrop occurs on less than 1 percent of

this landscape component. The dominant potential natural vegetation is needleand-thread/blue grama, bluebunch wheatgrass/blue grama, and sagebrush

/bluebunch wheatgrass. This component represents 40 percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 237
LTA70-M332D

LTA70-M332E

FROST SHATTERED MOUNTAIN RIDGE TOPS: METASEDIMENTARY (BELT)

Location: This LTA is located in the Fleecer, Highlands, Anaconda-Pintlar,

Pioneer, Beaverhead, Tendoy, and Lima Peaks (Beaverhead Mountains) ranges of

the Beaverhead/Deerlodge National Forest. It occurs in the Jefferson and

Madison River Basins in southwest Montana.

 Acreage by Section

 70-M332D 419

 70-M332E 132,440

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a relatively high

elevation, gently to moderately sloping, mountain landscape setting, at or

above the zone of moderate and strong frost shattering. The unit is typically

composed of frost shattered ridges and slopes, ranging from patterned ground

to soil heaving. Parent materials are colluvium and residuum from

metamorphosed sediments of the Precambrian Belt Supergroup, undifferentiated,

consisting of fine to coarse grained quartzite, siltite, argillite, carbonate,

and sandstone.

Accessory Characteristics: The primary soils are very shallow to moderately

deep, channery and flaggy sandy loams and loams. The vegetation is a mosaic of

alpine turf, subalpine grasslands, subalpine forest, montane coniferous forest

and mountain grassland. Mean annual precipitation ranges from 36 to 127

centimeters (14 to 50 inches). The elevation range of this LTA is 2134 to 3353

meters (7000 to 11000 feet). The dominant slopes have gradients of 25 to 50

percent. This LTA is slightly dissected by streams, with the dominant stream

pattern being dendritic. Wetlands, lakes and ponds are a minor component of

this unit. Some glaciated areas are included in this unit, but frost

shattering has become a dominant landform process since glaciation. 

LTA Components: This landtype association consists of frost shattered slopes

and ridges. 

Frost shattered slopes and ridges are formed in colluvium and residuum derived

from metasediment rocks comprised mostly of quartzite, siltite, and argillite.

Slope gradients range from 5 to 70 percent. Soils on these landforms are very

shallow to moderately deep, weakly to moderately developed, stony loamy sands,

sandy loams, and loams. These soils are classified as Typic and Alfic

Cryorthents, and Alfic, Dystric, and Typic Cryochrepts. Rock outcrop occurs on

about 15 percent of this landscape component. In the Highland Mountains, up to

50 percent of the unit is scree. The dominant potential natural vegetation is

sedge, Idaho fescue, subalpine fir, whitebark pine-subalpine fir, and big

sagebrush series. This component represents 98 percent of this LTA.

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 238
LTA72-M332Db

FROST SHATTERED MOUNTAIN RIDGE TOPS: WEAKLY WEATHERED GRANITICS

Location: This unit is located in the Little Belt Mountains of west-central

Montana.

 Acreage by Section

 72-M332Db 1,687

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a high elevation

mountain ridge landscape setting which is typically composed of frost

shattered ridges and upper valley sideslopes. Parent materials are colluvium

and residuum underlain by weakly weathered granitic rocks.

Accessory Characteristics: The primary subsoils are deep with clay loam

textures and contain 35 to 50 percent rock fragments. The vegetation is

coniferous forest. Mean annual precipitation ranges from 76 to 89 centimeters

(30 to 35 inches). The elevation range is 2286 to 2590 meters (7500 to 8500

feet). The dominant slopes have gradients of 0 to 40 percent. This unit is

slightly dissected by streams, with the dominant stream pattern being

dendritic. Wetlands are a minor component of this unit. Small areas of

glaciation are included in this map unit.

LTA Components: This landtype association consists of ridge tops and upper

valley sideslopes.

Upper valley sideslopes are formed in a thin layer of wind-deposited silt that

underlain by weakly weathered granitic rocks. Slope gradients range from 20 to

40 percent. Soils on this landform are deep and well drained. These soils are

weakly developed and consist of silt loam surface layers and clay loam

substrata. The dominant soils are classified as Typic Cryochrepts. Rock

outcrop occurs on less than 5 percent of this landscape component. The

dominant potential natural vegetation is subalpine fir, and whitebark

pine-subalpine fir series. This component represents 70 percent of this unit.

Frost shattered ridge tops are formed in residuum and colluvium derived from

weakly weathered granitic rocks. Slope gradients range from 0 to 20 percent.

Soils on this landform are deep and well drained, and are simlar to those

described above. Rock outcrop occurs on less than 5 percent of this landscape

component. The dominant potential natural vegetation is subalpine fir, and

whitebark pine-subalpine fir plant associations. This component represents 30

percent of this unit.

Compiled by: Robin Strathy, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 239
LTA72-M332Dc

LTA72-M332Dp

LTA72-M332E

LTA72-M331A

FROST SHATTERED MOUNTAIN RIDGE TOPS: WEAKLY WEATHERED GRANITICS

Location: This unit is located in the Gallatin, Madison, Absaroka-Beartooth

Mountain Ranges in southwestern Montana. Included are the Crazy Mountains,

Bridger Mountains, Anaconda Mountains and Continental Divide Uplands.

 Acreage by Section:

 72-M332Dc 1,571

 72-M332Dp 106

 72-M332E 838

 72-M331A 25,079

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit consists of rounded ridgetops

with weak stream dissection. Soil parent material is frost shattered glacial

till and colluvium derived from hard crystalline rocks such as granite.

Accessory Characteristics: Vegetation is alpine turf or sparse to dense upper

subalpine and lower subalpine forest. Elevation ranges from 1981 to 2987

meters (6500 to 9800 feet). Mean annual precipitation is greater than 125

centimeters (50 inches). Slopes ranges from 0 to 20 percent.

LTA Components: This landtype association has two components:

Soils on rounded ridgetops in forest are Typic and Dystric Cryochrepts. They

are deep, moderately coarse textured, rocky, and have low fertility and water

holding capacity. Rock outcrop makes up five percent of this component. The

dominant potential natural vegetation is the subalpine fir, and subalpine

fir-whitebark pine series. This component makes up 70 percent of this LTA.

Soils on rounded ridgetops with alpine turf are Dystric Cryochrepts. They are

moderately deep, coarse textured, rocky, and have low fertility and water

holding capacity. Rock outcrop makes up 20 percent of this component. A

common potential natural vegetation series is Idaho fescue. This component

makes up 30 percent of this LTA.

Compiled by: Henry Shovic, Gallatin National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 240
LTA73-M332D

LTA73-M332E

FROST SHATTERED MOUNTAIN RIDGE TOPS, VOLCANICS

Location: This LTA is located in the Gravelly, Fleecer, Boulder, Elkhorn, and

Anaconda-Pintlar (Beaverhead Mountains) Ranges of southwest Montana, in the

Jefferson and Madison River basins on the Beaverhead-Deerlodge National

Forest.

 Acreage by Section

 73-M332D 23,449

 73-M332E 14,106

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a relatively high

elevation, gently to moderately sloping mountain landscape setting at or above

the zone of moderate and strong frost churning. The unit is typically composed

of frost shattered ridges and slopes, ranging from patterned ground to soil

heaving. Parent materials are colluvium and residuum from mostly Tertiary

volcanic rocks and volcaniclastic rocks, including andesite, dacite, and

rhyolite, welded and non-welded tuffs, and locally minor metagabbro dikes.

Accessory Characteristics: The primary soils are shallow to moderately deep,

channery loams and sandy loams. The vegetation is mostly subalpine coniferous

forest. Mean annual precipitation ranges from 41 to 76 centimeters (16 to 30

inches). The elevation range of this LTA is 2134 to 2896 meters (7000 to 9500

feet). The dominant slopes have gradients of 5 to 20 percent. This LTA is

weakly dissected by streams, with the dominant stream pattern being dendritic,

or is undissected. Wetlands, lakes, and ponds are a minor component of this

LTA. 

LTA Components: This landtype association consists of frost shattered slopes

and ridges.

Frost shattered slopes and ridges are formed in colluvium and residuum derived

from volcanic rocks comprised mostly of rhyolite, welded tuffs, and andesite.

Slope gradients range from 5 to 50 percent. Soils on these landforms are

shallow to moderately deep, weakly to moderately developed, well drained

channery loams and sandy loams and extremely cobbly loams. These soils are

classified as Lithic and Typic Cryoboralfs, Lithic and Typic Cryochrepts, and

Typic Cryoborolls. Rock outcrop occurs on about 10 percent of this landscape

component. On the Helena NF, up to 25 percent of the unit is scree. The

dominant potential natural vegetation is whitebark pine-subalpine fir, rough

fescue, and Idaho fescue series. This component represents 100 percent of this

LTA.

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 241
LTA74-M332D

LTA74-M332E

LTA74-M331A

FROST SHATTERED MOUNTAIN RIDGE TOPS: SANDSTONES AND SHALES

Location: This LTA is located in the Pioneers, Fleecers, Beaverhead

Mountains, (south), Tendoys, Tobacco Roots, Gravellys, and Madison Ranges in

southwest Montana in the Jefferson and Madison River Basins.

 Acreage by Section

 74-M332D 859

 74-M332E 70,884

 74-M331A 9,208

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a relatively high

elevation, gently to moderately sloping mountain landscape setting, at or

above the zone of moderate and strong frost shattering. The unit is typically

composed of frost churned ridges and slopes, ranging from patterned ground to

soil heaving. Parent materials are colluvium and residuum from Tertiary

sediments consisting of shale, siltstone, sandstone, limestone, and calcareous

clays. Minor gypsum, chert, and volcanic rocks occur.

Accessory Characteristics: The primary soils are very shallow to moderately

deep silt loams, loams and clay loams. The vegetation is a mosaic of alpine

turf, alpine and subalpine coniferous forest, and mountain grasslands. Mean

annual precipitation ranges from 41 to 127 centimeters (16 to 50 inches). The

elevation range of this LTA is 2286 to 3048 (7500 to 10000 feet). The

dominant slopes have gradients of 10 to 40 percent. This LTA is slightly

dissected by streams, with the dominant stream pattern being dendritic. 

Wetlands, lakes, and ponds are a minor component of this LTA.

LTA Components: This landtype association consists of frost shattered ridges

and slopes. 

Frost shattered ridges and slopes are formed in colluvium and residuum derived

from sandstones and shales. Slope gradients range from 10 to 50 percent.

Soils on these landforms are very shallow to moderately deep, weakly to

moderately well developed, silt loams, loams, and clay loams. The surface

soils can be highly organic above 9000 feet (2743 meters). These soils are

classified as Lithic Cryoborolls and Typic Cryoborolls, Typic Cryochrepts, and

Mollic Cryoboralfs. Rock outcrop occurs on about 5 percent of this landscape

component. The dominant potential natural vegetation is Idaho fescue, sedge,

whitebark pine-subalpine fir, and Douglas-fir series. This component

represents 95 percent of this LTA.

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 242
LTA75-M332D

FROST SHATTERED MOUNTAIN RIDGE TOP: CALC-SILICATES AND QUARTZITES

Location: This LTA is located in the Little Belt Mountains on the Lewis and

Clark Forest.

 Acreage by Subsection

 75-M332D 36,716

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs on mountain ridge top flats

and consists of very old, clayey alluvial or glacial deposits of unknown

origin overlying sandstone or quartzite beds. Soils may be wet for extended

periods of time and develop perched water tables. 

Accessory Characteristics: Primary soils are very strongly developed topsoils

12 to 20 inches deep and contain 15 to 35 percent angular quartzite cobbles.

Soils are underlain by confining quartzite bedrock at depths of 60 inches or

greater. Subsoils are heavy clay and slowly permeable to water. Mean annual

precipitation ranges from 64 to 76 centimeters (25 to 30 inches). The

elevation range of this LTA is 1676 to 2286 meters (5500 to 7500 feet). The

unit is only slightly dissected by streams with the dominant stream pattern

being dendritic. Wetlands are a major component of the unit.

LTA Components: This landtype association consists of mountain ridgetops.

Gently sloping mountain ridgetops parallel the dip of underlying sandstone or

quartzite beds. Landforms have slope gradients that range from 0 to 25

percent. Soils on these landforms are strongly developed and consist of loam

topsoils, 12 to 20 inches thick, with mottles of reddish-brown color. 

Subsoils are a dark brown clay. Soils are classified as Aquic Cryoboralfs. 

Rock outcrop ocurrs on 5 percent of this landscape component. The dominant

potential natural vegetation is subalpine fir and spruce series. This

component represents 100 percent of this LTA.

Compiled by: Robin Strathy, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 243
LTA81-M332D

LTA81-M332E

LOW RELIEF HILLS: WEATHERED GRANITICS

Location: This LTA is located in the Boulder and Highland Mountains on the

Beaverhead-Deerlodge National Forest in southwest Montana. It occurs in the

upper Jefferson River and Clark Fork River Basins.

Acreage by Section:

 M332D 106,587

 M332E 77,434

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of rolling uplands. Parent materials are

residuum and colluvium underlain by weathered granitic bedrock.

Accessory Characteristics: The primary soils are shallow to deep with

gravelly sandy and loamy textures. The vegetation is coniferous forest and a

mosaic of shrublands and grasslands and coniferous forest. Small areas of

aspen are common. Mean annual precipitation ranges from 30 to 76 cms. (12 to

30 inches). The elevation range of this LTA is 1373 to 2591 meters (4500 to

8500 feet). The dominant slopes have gradients of 5 to 30 percent. This LTA is

moderately or highly dissected by streams, with the dominant stream pattern

being parallel or dendritic. Wetlands are a major component in this LTA.

LTA Components: This landtype association consists of two landform

components: rolling uplands and alluvial flats.

Rolling uplands are formed in weathered quartz monzonite and similar

coarse-grained igneous rocks of the Boulder Batholith. Slope gradients range

from 0 to 40 percent. Soils on these landforms are shallow, moderately deep,

to deep; are weakly to moderately developed, and have sandy loam, gravelly

sandy loam and loamy sand surface soils. The subsurface layers are gravelly

sandy loams, gravelly loamy sands and loamy sands in the less developed soils;

and gravelly sandy clay loams and sandy clay loams where subsoil clay

accumulation occurs. Ustochrepts, Eutroboralfs and Haploborolls prevail at the

lower elevations. Typic and Lithic Cryochrepts, Cryoboralfs and Cryoborolls

dominate at the mid to high elevations. Rock outcrop occurs on 5 to 15 percent

of this landscape component. Boulders are scattered on the surface on parts of

the unit. The dominant potential natural vegetation is Idaho fescue,

sagebrush, Douglas-fir, and subalpine fir series. This component represents 80

percent of this LTA.

Alluvial flats are formed in granitic alluvium and weathered granitic bedrock.

Slope gradients range from 0 to 15 percent. Soils on these landforms are

deep, weakly developed, with gravelly loamy textures. These soils are

classified as Oxyaquic and Typic Cryochrepts and Cryoborolls. Rock outcrop

does not occur on this landscape component. The dominant potential natural

vegetation is willow, sedge, spruce, and subalpine fir series. This component

represents 20 percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 244
LTA82-M332D

LTA82-M332E

LOW RELIEF HILLS: VOLCANICS

Location: This LTA is located in the Boulder Mountains on the

Beaverhead-Deerlodge Forest in southwest Montana. It occurs in the upper Clark

Fork River basin.

 Acreage by Section

 82-M332D 13,249

 82-M332E 6,817

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of rolling hills. Parent materials are

residuum underlain by Tertiary and Cretaceous volcanic bedrock, including

andesite, rhyolite, and welded and non-welded rhyolite and felsic tuffs.

Accessory Characteristics: The primary soils are shallow, moderately deep and

deep loamy soils often with high cobble contents. The vegetation is coniferous

forest and a mosaic of coniferous forest and shrubland/grassland. Mean annual

precipitation ranges from 38 to 75 cms. 15 to 30). The elevation range of this

LTA is 1525 to 2135 meters (5000 to 7000). The dominant slopes have gradients

of 5 to 30 percent. This LTA is slightly to moderately dissected by streams

with the dominant stream patterns being parallel. Wetlands are a minor

component of this LTA.

LTA Components: This landtype association consists of one landform component:

rolling hills.

Rolling hills are formed in colluvium and residuum over a variety of volcanic

bedrock. Slope gradients range from 5 to 30 percent. Soils on these landforms

are shallow, moderately deep and deep to bedrock. They are moderately and

weakly developed with cobbly and very cobbly loam surface textures. The

subsurface layers are cobbly and very cobbly loams and clay loams. These soils

are classified as Typic and Lithic Cryochrepts and Cryoborolls, and Typic and

Mollic Cryoboralfs. Rock outcrop occurs on about 10 percent of this landscape

component. The dominant potential natural vegetation is Idaho fescue,

sagebrush, Douglas-fir, and subalpine fir series. This component represents

100 percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 245
LTA83-M332D

LTA83-M332C

LOW RELIEF HILLS: FINE TERTIARY SEDIMENTS

Location: This LTA is located on the Lewis and Clark National Forest. It

occurs mostly in the Little Belt Mountains with minor amounts in the Rocky

Mountain Front.

 Acreage by Section

 83-M332D 95,156

 83-M332C 329

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a low relief hills

setting, which is typically composed of old clayey deposits. Parent materials

are residuum underlain by sedimentary rocks, usually sandstones and shales.

Accessory Characteristics: The primary soils are moderately deep with loamy

and clayey textures. The vegetation is coniferous forest. Mean annual

precipitation ranges from 51 to 76 centimeters (20 to 30 inches). The

elevation range of this LTA is 1676 to 2286 meters (5500 to 7500 feet). The

dominant slopes have gradients of 0 to 25 percent. This LTA is moderately

dissected by streams, with the dominant stream pattern being parallel.

Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of old clayey alluvial

deposits.

Old clayey alluvial deposits are formed in sandstone and shale sedimentary

rocks. Slope gradients range from 0 to 25 percent. Soils on these landforms

are moderately deep, strongly developed, with loamy and clayey textures. 

These soils are classified as Aquic Cryoboralfs. Rock outcrop generally is not

found in this landscape component. The dominant potential natural vegetation

is alpine fir habitat types. This component represents 100 percent of this

LTA.

Compiled by: Robin Strathy, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 246
LTA90-M332Dg

LTA90-M332Dh

MASS WASTED SLOPES: MIXED GEOLOGY

Location: This LTA in the Big Belt Mountains of the Missouri River basin.

 Acreage by Subsection

 90-M332Dg 2,678

 90-M332Dh 6,222

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a mountainous landscape

setting, which is typically composed of mountain slopes and ridges. Parent

materials are old landslide deposits underlain by highly weathered volcanic,

limestone and/or metasedimentary rock.

Accessory Characteristics: The primary soils are very deep and have clayey

subsoils. The vegetation is coniferous forest and/or mountain grassland.

Mean annual precipitation ranges from 50 to 63 centimeters (20 to 25 inches).

The elevation range of this LTA is 1678 to 2012 meters (5500 to 6600 feet).

The dominant slopes have gradients of 10 to 40 percent. This LTA is moderately

to highly dissected by streams, with the dominant stream pattern being

deranged. Wetlands are a major component of this LTA.

LTA Components: This landtype association consists of landslides.

Landslides are formed in landslide deposits associated with highly weathered

volcanic, limestone and/or metasedimentary bedrock. Slope gradients range from

10 to 40 percent. Soils on these landforms are very deep and well developed.

They have moderately fine textured surface layers and high subsoil clay

accumulations. They typically have silty clay loam or silt loam surface

textures. Subsoils are silty clay loam and silty clay with more than 35

percent rock (mostly gravel and cobble). These soils are classified as Mollic

Cryoboralfs. Argic Cryoborolls are associated with mountain grasslands.

Inclusions of Typic Cryaquolls are in bogs. The dominant potential natural

vegetation is subalpine fir on northerly aspects. Douglas-fir and subalpine

fir series are often on warmer aspects. The dominant potential natural

vegetation in the grassland areas is rough fescue.

Compiled by: Larry Laing, Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 247
LTA90-M332D

LTA90-331D

LTA90-M332C

MASS WASTED SLOPES: MIXED GEOLOGY

Location: This LTA is located primarily in the Little Belt and Big Snowy

Mountain Ranges on the Lewis and Clark Forest.

 Acreage by Section

 90-M332D 64,947 (Section except for M332Dg and M332Dh)

 90-331D 2,563

 90-M332C 67,245

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountainous landscape

setting, which is typically composed of valley sideslopes and benchy lower

valley slopes. The primary parent material is shale, but some undifferentiated

material is also present. 

Accessory Characteristics: The primary soils are deep, clayey and

loamy-skeletal silt loams and silty clay loams. The vegetation is coniferous

forest. Mean annual precipitation is 51 to 76 centimeters (20 to 30 inches).

The elevation range of this LTA is 1350 to 2100 meters (4500 to 7000 feet).

The dominant slopes have gradients of 10 to 40 percent. This LTA is moderately

dissected, with the dominant stream pattern being dendritic.

LTA Components: This landtype association consists of rotational slumps and

mud flows, benchy lower valley slopes, and upper valley sideslopes.

Rotational slumps and mud flows are formed shale. Slope gradients range from

10 to 40 percent. Soils on these landforms are moderately deep, weakly 

developed, and consist of mainly of loam, silt loam, and cobble. The major

soils are classified as Typic Cryochrepts. Rock outcrop occurs on less than 15

percent of this LTA. The dominant potential natural vegetation is subalpine

fir. This component represents 55 percent of this LTA.

Benchy lower valley slopes are formed in shale. Slope gradients range from 10

to 40 percent. Soils on these landforms are moderately deep and deep, weakly

developed, and consist of loam, silt loam and gravel. The major soils are

classified as Typic Cryoboralfs. Rock outcrop occurs on less than 15 percent

of this LTA. The dominant potential natural vegetation is Douglas-fir. This

component represents 30 percent of this LTA.

Upper valley sideslopes are formed in shale. Slope gradients range from 10 to

25 percent. Soils on these landforms are shallow, moderately developed and consist

mainly of loam and cobble. The major soils are classified as Mollic

Cryoboralfs. Rock outcrop occurs on less than 15 percent of this LTA. The

dominant potential natural vegetation is Douglas-fir. This component

represents 15 percent of this LTA.

Compiled by: Richard Saunders and Robin Strathy, Lewis and Clark National

Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 248
LTA92-M332D

LTA92-M332B

LTA92-M332E

COLLUVIAL SLOPES: MIXED GEOLOGY

Location: This LTA is located throughout the Helena National Forest.

 Acreage by Section

 92-M332D 12,928

 92-M332B 6,383

 92-M332E 3,557

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a mountainous landscape

setting, which is typically composed of mountain slopes and ridges. Parent

materials are colluvial deposits, in basins and on toeslopes, typically

influenced by metasedimentary and volcanic rocks.

Accessory Characteristics: The primary soils are very deep and have loamy or

clayey subsoils. The vegetation is coniferous forest. Mean annual

precipitation ranges from 38 to 75 centimeters (15 to 30 inches). The

elevation range of this LTA is 1464 to 2135 meters (4800 to 7000 feet). The

dominant slopes have gradients of 10 to 50 percent. This LTA is highly

dissected but weakly incised by streams, with the dominant stream pattern

being parallel or subparallel. Wetlands are a major inclusion in this LTA.

LTA Components: This landtype association consists of colluvial deposits.

Colluvial deposits are derived from metasedimentary and volcanic rock. Some

areas are also influenced by limestone colluvium. Slope gradients range from

10 to 50 percent. Soils on these landforms are very deep and weakly to well

developed. They have moderately fine textured surface layers and high subsoil

clay accumulations. They typically have very cobbly loam or cobbly silt loam

surface textures. Subsoils are very cobbly loam, clay loam or silty clay

loam. These soils are classified as Typic Cryochrepts, Typic Cryoboralfs, and

Argic Cryoborolls. Inclusions of Aquic Cryoborolls, Aquic Cryoboralfs and

Typic Cryaquepts are associated with seeps and springs. The dominant potential

natural vegetation is subalpine fir, spruce and Douglas-fir.

Compiled by: Larry Laing, Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 249
CHAPTER 9

LTA Descriptions

Section M332E Beaverhead Mountains

This Section occurs in southwest Montana and east-central Idaho. It is part of

the Southwest Montana Mountains and Valleys geomorphic area previously

described. Forty seven LTAs were mapped in this Section. See Appendix F for a

complete list of LTAs and their acreages. The map unit descriptions are

preceded by the following illustrations:

 Figure 35: Map showing location of M332E within the Northern Region

 Figure 36: M332E landscape photograph, Tendoy Mountains

 Beaverhead-Deerlodge National Forest

 Figure 37: Map showing distribution of LTAs within M332E

 

 Figure 38 Bar chart showing abundance of landform groups within M332E

 Figure 39: Bar chart showing abundance of geologic material

 groups within M332E

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 250
LTA10-M332En

VALLEYS: RECENT COARSE ALLUVIUM

Location: This LTA is located throughout the Snowcrest, Greenhorn and Gravelly

mountain ranges and basins in southwest Montana which are drained by the Ruby

and Madison Rivers in the Jefferson River Basin.

 Acreage by Subsection

 10-M332En 3,699

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in valley bottoms and

alluvial basins. The coarse alluvium is derived gneiss, metasedimentary rocks,

sandstones and related rock types.

Accessory Characteristics: Dominant soils are deep to very deep coarse loams.

There are minor amounts of organic soils and soils with organic surfaces. The

vegetation varies from sedges, willows and wet forb types to conifers with

moist forb understories. Mean annual precipitation ranges from 41 to 76

centimeters (16 to 30 inches). The elevation range is 2012 to 1622 meters

(6600 to 8600 feet). The slope range is 0 to 20 percent, with dominant slopes

5 to 15 percent. This unit is slightly to moderately dissected by streams,

with the stream pattern being dendritic. 

 

LTA Components This landtype association consists of alluvial basins, and

valley bottoms.

Alluvial basins are wide openings in a valley bottom drained by a meandering

stream and underlain by sediments deposited by running water. Slopes range

from 0 to 20 percent with dominant slopes, 2 to 15 percent. Dominant soils

include Pachic Cryoborolls and Cryaquolls under mountain big sagebrush and

Idaho fescue series. Under carex, willow and moist forb series the soils are

Histic Cryaquolls or be Histisols. Under spruce and subalpine fir series,

soils are Typic Cryochrepts. Soils are well to excessively drained. This

component represents about 70 percent of the unit.

Valley bottoms are areas containing the present stream and built of sediment

deposited during overflows during flood stages of past and present stream

regimes. The slopes range 0 to 20 percent with dominant slopes, 2 to 15

percent. Soils are poorly developed and include Fluvents under carex and

willow series. Typic Cryoborolls and Cryaquolls occur under mountain big

sagebrush and Idaho fescue series. Under spruce and subalpine fir series,

Typic Cryochrepts occur. Mottles can be present throughout the soil profile

indicative of fluctuating water tables. Soils contain numerous rock fragments

and are very gravelly or very cobbly. Stones or boulders can be present at

depth in the soil. This component represents 30 percent of the unit.

Compiled by: Annie Greene, Beverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 251
LTA10-M332E

LTA10-M331Am

LTA10-M331Ap

VALLEYS: RECENT COARSE ALLUVIUM

Location: This LTA is located in the Beaverhead, Anaconda Pintlar, Fleecer,

Pioneer, Lima, Tendoy, and Madison Ranges. These are in southwest Montana in

the Jefferson and Madison Basins.

 Acreage by Section

 10-M332E 88,274 (Section except for M332En)

 10-M331Am 5,925

 10-M331Ap 6,935

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a valley bottom and

alluvial fan landscape setting, which is typically composed of glacial outwash

plains, stream terraces, and alluvial fans. Parent materials are

undifferentiated deposits of silts, sands, gravels, and cobbles, which can be

underlain by any bedrock.

Accessory Characteristics: The primary soils are shallow to moderately deep,

gravelly loamy sands. The vegetation is a mosaic of deciduous shrubs,

deciduous forest, coniferous forest, upland grasslands, and wet meadow. Mean

annual precipitation ranges from 41 to 102 centimeters (16 to 40 inches). The

elevation range of this LTA is 1951 to 2804 meters (6400 to 9200 feet. The

dominant slope gradients are 0 to 15 percent. This LTA is slightly dissected

by streams, with the dominant stream pattern being dendritic. Wetlands are a

major component of this LTA.

LTA Components: This landtype association consists of glacial outwash plains,

stream terraces, and alluvial fans.

Glacial outwash fans are formed in relatively coarse alluvium. Slope gradients

range from 0 to 10 percent. Soils on these landforms are shallow to moderately

deep, poorly developed, well to excessively drained gravelly loamy sands and

sandy loams. Predominant soils are classified as Typic Cryochrepts. Rock

outcrop occurs on less than one percent of this landscape component. The

dominant potential natural vegetation is mountain big sagebrush and Idaho

fescue series. This component represents sixty percent of this land type

association. 

Stream terraces are formed in mixed alluvium and reworked glacial outwash.

Slope gradients range from 0 to 5 percent. Soils on these landforms are

shallow to moderately deep, poorly developed, well-drained gravelly loams and

sandy loams. Predominant soils are classified as Typic Cryorthents, and Typic

Cryochrepts. Rock outcrop does not occur in this unit. The dominant

potential natural vegetation is Douglas-fir and mountain big sage series. 

This component represents 20 percent of this land type association.

Alluvial fans are formed in alluvium. Slope gradients range from 5 to 15

percent. Soils on these landforms are shallow, poorly developed, well-drained

gravelly sandy loams. Predominant soils are classified as Typic Cryochrepts,

and Typic Cryoborolls. Rock outcrop does not occur in this unit. The dominant

potential natural vegetation is mountain big sage. This component represents

20 percent of this LTA.

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 252
LTA12-M332E

VALLEYS: OUTWASH AND OTHER OLDER COARSE ALLUVIUM

Location: This LTA is located in foothills near the Boulder, Highland and

Tobacco Root Mountains on the Beaverhead-Deerlodge National Forest. It occurs

in the upper Boulder and Jefferson River basins.

 Acreage by Subsection

 12-M332E 50,641 (Section except for M332En)

 

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a valley landscape

setting, which is typically composed of alluvial fans and glacial terraces.

Parent materials are coarse alluvium and glacial outwash over undifferentiated

bedrock.

Accessory Characterisics: The primary soils are deep with cobbly sandy and

gravelly sandy and loamy textures. The vegetation is a mosaic of shublands and

grasslands with a minor inclusion of coniferous forest. Mean annual

precipitation ranges from 23 to 46 centimeters (9 to 18 inches). The elevation

range of this LTA is 1373 to 1951 meters (4500 to 6400 feet). The dominant

slopes have gradients of 5 to 15 percent. This LTA is moderately tohighly 

dissected by intermittent streams, with the dominant stream pattern being

parallel. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of alluvial fans and

glacial terraces.

Alluvial fans are formed in coarse alluvial and glacio-fluvial deposits

originating from a variety of bedrock types. The majority of this LTA consists

of a series of coalescing alluvial fans. Slope gradients range from 1 to 15

percent. Soils on these landforms are moderately deep to deep, weakly to

moderately developed, and have cobbly and gravelly sandy loam and loam surface

soils. The subsurface layers are cobbly sandy loams and loams in the less

developed soils and cobbly sandy clay loams and clay loams where subsoil clay

accumulation occurs, These soils are classified as Ustochrepts, Argiborolls,

and Haploborolls. Rock outcrop occurs on less than 1 percent of this landscape

component. The dominant potential natural vegetation is needle-and-thread

grass/blue grama; bluebunch wheatgrass/blue grama; and sagebrush/bluebunch

wheatgrass habitat types. This components represents 95 percent of this LTA.

Glacial terraces are formed in coarse glacio-fluvial deposits. This component

is represented by one mapping unit at the mouth of Rock Creek in the upper

Boulder River. Slope gradients range from 0 to 20 percent. Soils on this

landform are deep, weakly to moderately developed, with cobbly, sandy and loamy

textures. They are classified as Typic Cryochrepts and Cryoboralfs, and Argic

and Typic Cryoborolls. Rock outcrop does not occur in this landform component.

The dominant potential natural vegetation is a mosaic of Douglas fir

/twinflower, dwarf huckleberry, and pinegrass; sagebrush/rough fescue; and

rough fescue/Idaho fescue habitat types. This component represents 5 percent

of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 253
LTA12-M332En

VALLEYS: OUTWASH AND OTHER OLDER COARSE ALLUVIUM

Location: This LTA is located throughout the Greenhorn and Gravelly mountain

ranges and basins. These are in southwest Montana and are drained by the Ruby

and Madison rivers in the Jefferson Basin

 Acreage by Section

 12-M332En 10,365

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs on glacial outwash

plains and is comprised glacial till dominated by granite and gneiss. Other

undifferentiated competent rock types are present. This till was deposited by

meltwater streams beyond the extent of glacial ice.

Accessory Characteristics: The primary soils are moderately deep to very

deep, very cobbly to stony, coarse loams and sandy loams. Vegetation varies

from shrublands and grasslands to conifers. Minor areas of deciduous forests

occur. Elevation ranges from 1951 to 2560 meters (6400 to 8400 feet). Mean

annual precipitation is 40 to 75 centimeters (16 to 30 inches). Slopes range 0

to 20 percent, with dominant slopes 5 to 15 percent. This unit is slightly

dissected by streams with the stream pattern being dendritic.

LTA Components: This landtype association consists of glacial outwash plains.

Glacial outwash plains are dominated on the surface by undifferentiated stone

to boulder size glacial till. Granite and gneiss are the dominant parent

materials. Dominant soils are Typic Cryoborolls under mountain big sagebrush

and Idaho fescue series. Under Douglss-fir and subalpine fir series, Typic

Cryochrepts are present. Slopes range 0 to 20 percent with dominant slopes 5

to 15 percent.

Compiled by: Annie Greene, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 254
LTA13-M332En

VALLEYS: FINE GLACIAL SEDIMENTS

Location This LTA is located throughout the Snowcrest and Gravelly mountain

ranges and basins in southwest Montana. These are drained by the Ruby and

Madison Rivers in the Jefferson River Basin.

 Acreage by Subsection

 13-M332En 12,914

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs on glacial outwash

plains and is contains glacial till dominated by competent shales, limestones

and sandstones. This till was deposited by meltwater streams beyond the extent

of glacial ice.

Accessory Characteristics: The primary soils are moderately deep to very

deep, very gravelly to very stony loams. Vegetation varies from shrublands,

grasslands to conifers. The elevation range is 1951 to 2560 meters (6400 to

8400 feet). Mean annual precipitation is 40 to 76 centimeters (16 to 30

inches). Slope ranges from 0 to 20 percent with dominant slopes of 5 to 15

percent. The unit is moderately to highly dissected by streams with the

stream pattern being dendritic.

LTA Components: This landtype association consists of glacial outwash plains.

Glacial outwash plains are dominated on the surface by stone sized glacial

till derived from competent shales, limestones and sandstones. Dominant soils

are Pachic Cryoborolls and Typic Cryoborolls under mountain big sagebrush,

Idaho fescue and Douglas-fir series. Under subalpine fir series, Typic

Cryocrepts are present. Slopes range from 0 to 20 percent, with dominant

slopes of 5 to 15 percent.

Compiled by: Annie Greene, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 255
LTA14-M332En

VALLEYS: RECENT FINE ALLUVIUM

Location: This LTA is located throughout the Snowcrest and Gravelly mountain

ranges and basins in southwest Montana. These are drained by the Ruby and

Madison Rivers in the Jefferson River Basin.

 Acreage by Subsection

 14-M332En 11,728

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in valley bottoms and

alluvial basins. The fine alluvium is derived from shale, fine-grained

sandstone, limestone and related rocks.

Accessory Characteristics: Dominant soils are deep to very deep fine loams to

clays. There are minor amounts of organic soils and soils with organic

surfaces. The vegetation varies from sedges, willows and wet forb types to

conifers with moist undertory forbs. Mean annual precipitation ranges from 41

to 76 centimeters (16 to 30 inches). The elevation range is 1860 to 2317

meters (6100 to 7600 feet). The slope range is 0 to 20 percent, with dominant

slopes 5 to 15 percent. This LTA is highly dissected by streams, with dominant

stream patterns being dendritic.

LTA Components: This landtype association consists of alluvial basins, and

valley bottoms.

Alluvial basins are wide openings in a valley bottom drained by a meandering

stream and underlain by sediments deposited by running water. The slope range

is 0 to 20 percent, with dominant slopes 5 to 15 percent. Dominant soils

include Argic Cryoborolls and Argic Pachic Cryoborolls under mountain big

sagebrush, Idaho fescue, tufted hairgrass and Douglas-fir series. Under carex

and moist forb series soils are Histic Cryaquolls or Histosols. Under spruce

and subalpine fir series Typic Cryochrepts are present. All soils can have

mottles or gleying present indicating high water tables. This component

represent 60 percent of the unit.

Valley bottoms are areas containing the present stream and built of sediment

deposited during overflows during flood stages of past and present stream

regimes. Slopes range 0 to 20 percent, with dominant slopes 5 to 15 percent.

Soils can be poorly developed and include Fluvents and Cryaquolls under carex

and willow series. Under mountain big sagebrush, Idaho fescue, tufted

hairgrass, and Douglas-fir series; Calcic Pachic Cryoborolls and Typic

Cryoborolls are present. Typic Cryochrepts are present under spruce and

subalpine fir series. Soils contain numerous rock fragments and are very

gravelly to very cobbly. Stones or boulders can be present at depth in the

soils. This component represent 40 percent of the unit.

Compiled by: Annie Greene, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 256
LTA14-M332E

LTA14-M331A

VALLEYS: RECENT FINE ALLUVIUM

Location: This LTA is located in the Beaverhead, Anaconda-Pintlar, Fleecer,

Pioneer, Lima, Tendoy, and Madison Ranges. These are in southwest Montana in

the Jefferson and Madison Basins.

 Acreage by Section

 14-M332E 83,204 (all of Section except M332En)

 14-M331A 12,271

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in the larger valley

bottoms, which is typically composed of floodplains, glacio-fluvial wetlands,

and outwash alluvium. Parent materials are recent alluvium and glacio-fluvial

outwash deposits.

Accessory Characteristics: The primary soils are deep with fine textures and

organics. The vegetation is a mosaic of riparian deciduous and coniferous

forest, riparian shrub meadows and sedge meadows. Mean annual precipitation

ranges from 50 to 102 centimeters (20 to 40 inches). The elevation range of

this LTA is 2073 to 2896 meters (6800 to 9500 feet). The dominant slopes have

gradients of 0 to 10 percent. This LTA is highly dissected by streams, with

the dominant stream pattern being dendritic. Wetlands are a major component

of this LTA.

LTA Components: This landtype association consists of floodplains,

glacio-fluvial wetlands, and outwash alluvium.

The floodplains are formed in variable alluvium, typically finer and/or

organic nearer the surface. Slope gradients range from less than one to four

percent. Soils on these landforms are typically deep, weakly to moderately

developed, poorly drained sands to silt, often with organic surface soils. 

These soils are classified as Histic Cryaquolls and Aquic Cryoborolls. Rock

outcrop does not occur. The potential natural vegetation is a variety of

riparian/wetland communities, such as willow and sedge. This component

represents about 50 percent of this LTA.

Alluvial wetlands are formed in relatively fine glacial outwash and sediments,

in glaciofluvial valley fill deposits. Slope gradients range from 1 to 10

percent. Soils on these landforms are deep, poorly drained, weakly to

moderately developed, silt loams and silty clay loams, often with organic

surface soils. These soils are classified as Histic Cryaquolls and Aquic

Cumulic Cryoborolls. Rock out crop does not occur in these wetlands, but do

occur in the intermingled uplands. The dominant potential natural vegetation

is tufted hairgrass series. This component represents about 30 percent of this

LTA. 

Outwash alluvium is formed in glacial outwash and mixed alluvium and glacial

outwash. Slope gradients range from 1 to 15 percent. Soils on these landforms

are deep organic soils and deep, poorly drained silt loams and sandy loams.

These soils are classified as Sapric Terric Medihemists and Oxyaquic

Cryoborolls. Rock outcrop does not occur in this unit. The dominant potential

natural vegetation is comprised of various willow and wet meadow communities.

Typical potential vegetation is willow and sedges. This component represents

about 20 percent of this LTA.

Compiled by: Dan Svoboda, Beaverhead-DeerLodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 257
LTA20-M332E

BREAKS: METASEDIMENTARY (BELTS)

Location: This LTA is located in the Fleecer, Pioneer, Beaverhead, Lima, and

Tendoy Ranges. These occur in southwest Montana in the Jefferson and Madison

Basins.

 Acreage by Section

 20-M332E 72,264

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in steep, deeply eroded

(rejuvenated), or faulted mountainous landscape settings, which is typically

composed of structural and stream breaks. Parent materials are colluvium and

residuum underlain by metamorphosed sediments of the Precambrian Belt

Supergroup undifferentiated, consisting of fine to coarse grained quartzite,

siltite, argillite, and carbonate and sandstone.

Accessory Characteristics: The primary soils are very shallow to moderately

deep, channery and flaggy loamy sands to loams. The vegetation is a mosaic of

open, coniferous forest and mountain grassland. Mean annual precipitation

ranges from 41 to 102 centimeters (16 to 40 inches). The elevation range of

this LTA is 2012 to 3048 meters (6600 to 10000 feet). The dominant slopes have

gradients of 50 to 70 percent. This LTA is highly to moderately dissected by

streams, with the dominant stream pattern being dendritic and parallel. 

LTA Components: This landtype association consists of breaks.

Breaks are formed in colluvium and residuum. Slope gradients range from 40 to

75 percent. Soils on these landforms are very shallow to shallow, weakly

developed, well to excessively drained, channery and flaggy loamy sands to

loams. These soils are classified as Lithic and Typic Cryorthents, sandy

skeletal to loamy skeletal, mixed; and Lithic and Typic Cryochrepts, loamy

skeletal, mixed. Rock outcrop can account for up to a third of this landscape

component. The dominant potential natural vegetation is Douglas-fir, big

sagebrush, subalpine fir and whitebark pine series. This component represents

100 percent of this LTA.

Compiled by: Dan Svoboda, Beaverhead/Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 258
LTA21-M332E

LTA21-M332D

BREAKS: HIGHLY WEATHERED GRANITICS

Location: This LTA is located in the Anaconda-Pintlar, Fleecer, Pioneer,

Boulder, Bull, Highland, and Tobacco Root Mountains on the Beaverhead

-Deerlodge National Forest. These occur in southwest Montana in the Jefferson

and Madison River Basins.

 Acreage by Section

 21-M332E 41,402

 21-M332D 8,423

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in steep, deeply eroded

(rejuvenated), or faulted mountainous landscape settings which is typically

composed of structural and stream breaks. Parent materials are colluvium and

residuum derived from moderately to highly weathered Cretaceous to Tertiary

intrusive rocks undifferentiated, consisting mainly of granite, quartz

monzonite, and granodiorite.

Accessory Characteristics: The primary soils are shallow to moderately deep,

well drained, gravelly sandy loams. The vegetation is a mosaic of coniferous

forest and mountain grasslands. Mean annual precipitation ranges from 41 to

102 centimeters (16 to 40 inches). The elevation range of this LTA is 2012 to

3048 meters (6600 to 10000 feet). The dominant slopes have gradients of 40 to

75 percent. This LTA is highly to moderately dissected by streams, with the

dominant stream pattern being dendritic to parallel. 

LTA Components: This landtype association consists of breaks. 

Breaks are formed in colluvium and residuum. Slope gradients range from 40 to

75 percent. Soils on these landforms are shallow to moderately deep, weakly

developed, well drained, channery sandy loams and loams. These soils are

classified as Typic Cryorthents, and Lithic and Typic Cryochrepts. Rock

outcrop accounts for up to a quarter of this landscape component. The dominant

potential natural vegetation is Douglas-fir, big sagebrush, subalpine fir, and

whitebark pine series. This component represents 100 percent of this LTA.

Compiled by: Dan Svoboda and Dave Ruppert, Beaverhead-DeerLodge National

Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 259
LTA23-M332E

LTA23-M331A

BREAKS: SCHIST AND GNEISS

Location: This LTA is located in the Lima Peaks, Tendoy, Tobacco Root, and

Madison mountain ranges of the Beaverhead National Forest. These occur in

southwest Montana in the Jefferson and Madison Basins.

 Acreage by Section

 23-M332E 23,278

 23-M331A 25,213

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a steep, deeply eroded

(rejuvenated), or faulted mountainous landscape settings which is typically

composed of structural and stream breaks. Parent materials are colluvium and

residuum derived from Pre-Belt crystalline metamorphic rocks consisting of

hornblende gneiss, quartzite, meta-diabase, sillimanite schist,

quarts-feldspar gneiss, metamorphosed granite and migmatite, including the

Dillon Granite-Gneiss in the Tendoy Mountains.

Accessory Characteristics: The primary soils are very shallow to moderately

deep, well-drained, channery sandy loams and loams. The vegetation is a mosaic

of coniferous forest and mountain grasslands. Mean annual precipitation ranges

from 41 to 102 centimeters (16 to 40 inches). The elevation range of this LTA

is 2012 to 3048 meters (6600 to 10000 feet). The dominant slopes have

gradients of 40 to 75 percent. This LTA is highly to moderately dissected by

streams, with the dominant stream pattern being dendritic to parallel.

Wetlands, lakes, and ponds are not a component of this LTA. 

LTA Components: This landtype association consists of breaks.

Breaks are formed in colluvium and residuum. Slope gradients range from 40 to

75 percent. Soils on these landforms are very shallow to moderately deep,

well-drained, weakly developed channery sandy loams to loams. These soils are

classified as Lithic and Typic Cryorthents, and Lithic and Typic Cryochrepts.

Rock outcrop occurs on about 25 percent of this landscape component. The

dominant potential natural vegetation is Douglas-fir, big sagebrush, subalpine

fir and whitebark pine series. This component represents 100 percent of LTA.

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 260
LTA25-M332E

LTA25-M331A

BREAKS: SANDSTONES AND SHALES

Location: This LTA is located in the Lima Peaks, Tendoy, Pioneer, Fleecer,

and Madison mountains of the Beaverhead/Deerlodge National Forest. These

occur in southwest Montana in the Jefferson and Madison Basins.

 Acreage by Section

 25-M332E 45,709

 25-M331A 69,798

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a steep, deeply eroded

(rejuvenated), or faulted mountainous landscape settings which is typically

composed of structural and stream breaks. Parent materials ar e colluvium and

residuum derived from Tertiary to Cambrian sediments undifferentiated

consisting of shale, siltstone, sandstone, limestone and calcareous clays.

Minor gypsum, chert, and volcanic rock occurs. 

Accessory Characteristics: The primary soils are shallow to deep, well

drained, flaggy loams, clay loams, and sandy loams. The vegetation is a mosaic

of coniferous forest and mountain grasslands. Mean annual precipitation ranges

from 41 to 102 centimeters (16 to 40 inches). The elevation range of this LTA

is 1829 to 3048 meters (6000 to 10000 feet). The dominant slopes have

gradients of 35 to 75 percent. This LTA is highly to moderately dissected by

streams, with the dominant stream pattern being dendritic to parallel.

Wetlands, seeps are a minor component of this LTA. 

LTA Components: This landtype association consists of breaks.

Breaks are formed in colluvium and residuum. Slope gradients range from 20 to

65 percent. Soils on these landforms shallow to deep, well drained, weakly to

moderately developed, flaggy loams, clay loams, and sandy loams. These soils

are classified as Typic Cryochrepts and Typic Cryumbrepts. Rock outcrop occurs

on up to 20 percent of this landscape component. The dominant potential

natural vegetation is Douglas-fir, low sagebrush, big sagebrush, subalpine fir

and whitebark pine series. This component represents 100 percent of this LTA.

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 261
LTA27-M331A

BREAKS: VOLCANICS AND CARBONATES

Location: This LTA is located in the Lima Peaks, Tendoy, Pioneer, Fleecer,

Tobacco Root, and Madison mountain ranges in the Beaverhead National Forest.

These occur in southwest Montana in the Jefferson and Madison Basins.

 Acreage by Section

 27-M332E 62,706

 27-M331A 6,506

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a steep, deeply eroded

(rejuvenated), or faulted mountainous landscape setting which is typically

composed of structural and stream breaks. Parent materials ar e colluvium and

residuum derived largely from volcanics and limestone rocks of various ages.

Accessory Characteristics: The primary soils are shallow to moderately deep,

well-drained channery loams. The vegetation is a mosaic of mountain grasslands

and open coniferous forest. Mean annual precipitation ranges from 41 to 102

centimeters (16 to 40 inches). The elevation range of this LTA is 2012 to 2591

meters (6600 to 8500 feet). The dominant slopes have gradients of 55 to 75

percent. This LTA is moderately to highly dissected by streams, with the

dominant stream pattern being dendritic to parallel. Wetlands and seeps are a

minor component of this LTA.

LTA Components: This landtype association consists of breaks. 

Breaks are formed in colluvium and residuum. Slope gradients range from 45 to

85 percent. Soils on these landforms are shallow, well drained, weakly

developed, channery loams. These soils are classified as Lithic and Typic

Cryochrepts. Rock outcrop occurs on about one third of this landscape

component. The dominant potential natural vegetation is low sagebrush,

curlleaf mountain mahogany and Douglas-fir series. This component represents

100 percent of this LTA.

Compiled by: Dan Svoboda, Beaverhead-DeerLodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 262
LTA34-M332En

HIGH RELIEF MOUNTAIN SLOPES: VOLCANICS

Location: This LTA is located throughout the Snowcrest and Gravelly mountain

ranges which are drained by the Ruby and Madison Rivers in the Jefferson River

Basin

 Acreage by Subsection

 34-M332En 9,181

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in non-glacial mountain

slopes and is composed of colluvium derived from rhyolitic volcanic flows,

welded tuffs, and andesitic porphyry, and basalts.

Accessory Characteristics: Dominant soils are moderately deep to very deep

gravelly and very cobbly loams. Vegetation varies from shrublands and

grasslands to conifers. Mean annual precipitation is 51 to 102 centimeters (20

to 40 inches). Elevation ranges from 1951 to 2744 meters (6400 to 9000 feet).

Slopes range from 40 to greater than 70 percent, with dominant slopes being 40

to 60 percent. This LTA is moderately to highly dissected with streams

dominantly having a parallel stream pattern.

LTA Components: This landtype association consists of steep mountain slopes.

Steep mountain slopes are formed in colluvium derived from rhyolitic volcanic

flows, welded tuffs and andesites. Slopes range from 40 to over 70 percent,

with slopes of 40 to 60 percent predominating. Soils are moderately deep to

deep with numerous rock fragments. Dominant soils include Typic Cryoborolls

under mountain big sagebrush, Idaho fescue and Douglas-fir series and Typic

Cryochrepts under subalpine fir and whitebark pine series. Rock outcrop occurs

on 10 to 30 percent of this unit.

Compiled by: Annie Greene, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 263
LTA35-M332En

WEAKLY GLACIATED MOUNTAIN SLOPES AND RIDGES: QUARTZITES

Location: This LTA is located throughout the Snowcrest and Gravelly mountain

ranges which are drained by the Ruby and Madison Rivers in the Jefferson River

Basin

 Acreage by Subsection

 

 35-M332En 19,160

 

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in both glacial and

non-glacial mountain slopes and is composed of moderate to steep mountain

slopes, glacial trough walls and ridge tops. Soils formed in colluvium and

residuum derived from (non-Belt) Paleozoic quartzites. Minor amounts of

sandstone and associated cherts are included.

Accessory Characteristics: Dominant soils are shallow to deep coarse sandy to

loams with numerous rock fragments. Vegetation varies from shrublands and

grasslands to conifers. Mean annual precipitation ranges from 51 to 102

centimeters (20 to 40 inches). Elevation ranges 2134 to 2927 meters (7000 to

9600 feet). Slopes range from 20 to greater than 60 percent, with dominant

slopes 30 to 50 percent. This LTA is moderately to highly dissected with

streams dominantly having a parallel stream pattern.

LTA Components: This landtype association consists of moderate to steep

mountain slopes, ridge tops, and glacial trough walls.

Moderate to steep mountain slopes formed in colluvium derived from quartzites

and minor amounts sandstone and associated cherts. Slopes range 20 to +60

percent, with dominant slopes 30 to 50 percent. Soils are moderately deep on

steeper slope gradients. Dominant soils include Typic Cryoborolls under

mountain big sagebrush, Idaho fescue and tufted hairgrass. Typic Cryochrepts

occur under Douglas-fir, subalpine fir, and whitebark pine series. Dystric

Cryochrepts and Typic Cryumbrepts also occur under whitebark pine series. Rock

outcrop accounts for 5 to 20 percent of this component. This component

represents 50 percent of the map unit

Ridge tops are formed in residuum derived from quartzites, sandstones and

associated cherts. Soils are moderately deep to deep. There are minor amounts

of very shallow to shallow soils. Slopes range from 0 to 20 percent, with

dominant slopes 5 to 15 percent. Dominant soils include Typic Cryoborolls

under Idaho fescue and tufted hairgrass series. Typic Cryumbrepts occur under

alpine tundra and whitebark pine habitat types. Under subalpine fir series

there are Typic Cryochrepts. Rock outcrop accounts for 5 to 20 percent of this

component. This component represents 20 percent of the unit

Glacial trough walls are slopes of glacial eroded valleys. Soils are shallow

to moderately deep. Slopes range from 40 to +60 percent with dominant slopes 

40 to 60 percent. Dominant soils are Typic Cryochrepts under subalpine fir and

whitebark pine series. Rock outcrop and talus accounts for 20 to 40 percent of

this component. This component represents 20 percent of the map unit.

Compiled by: Annie Greene, Beaverhead-DeerLodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 264
LTA36-M332En

HIGH RELIEF MOUNTAIN SLOPES: SANDSTONES AND SHALES

Location: This LTA is located in the Snowcrest and Gravelly mountains in

southwest Montana which are drained by the Ruby and Madison Rivers in the

Jefferson River Basin.

 Acreage by Subsection

 36-M332En 6,646

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in non-glaciated steep

mountain slopes in colluvium derived from Mesozoic shales and siltstones with

minor amounts of interbedded sandstone.

Accessory Characteristics: Dominant soils are moderately deep to deep loams

to clays with numerous rock fragments. The vegetation varies from shrublands

and grasslands to conifers. Mean annual precipitation ranges from 51 to 76

centimeters (20 to 30 inches). Elevations range from 2256 to 2866 meters (7400

to 9400 feet). Slopes range 45 to greater than 80 percent, dominant slopes are

50 to 70 percent. This unit is highly dissected by streams, with dominant

stream patterns being parallel.

LTA Components: This landtype association consists of steep mountain slopes.

Steep mountain slopes formed in colluvium. Slopes range from 45 to +80

percent; dominant slopes are 50 to 70 percent. Soils are moderately deep to

deep. Dominant soils include Typic Cryoborolls and Argic Cryoborolls under

mountain big sagebrush, bluebunch wheatgrass, and Idaho fescue series. Typic

Cryochrepts occur under limber pine, Douglas-fir, subalpine fir and whitebark

pine series. Rock outcrops occur on 5 to 20 percent of this unit.

Compiled by: Annie Greene, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 265
LTA37-M332En

HIGH RELIEF MOUNTAIN SLOPES: CARBONATES

Location: This LTA is located throughout the Snowcrest, Gravelly and

Greenhorn mountains in southwest Montana which are drained by the Ruby and

Madison Rivers in the Jefferson River Basin.

 Acreage by Subsection

 37-M332En 33,777

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in non-glaciated

mountain slopes and is composed of steep mountain slopes and ridge tops.

Parent materials are colluvium derived from Cretaceous, Triassic, Paleozoic

limestones with minor amounts of interbedded calcareous shales, Archaen

marbles and dolomites.

Accessory Characteristics: Dominant soils are moderately deep to deep loamy

soils with numerous rock fragments. The vegetation varies from mountain

shrublands, grasslands, and conifers to alpine tundra. Mean annual

precipitation ranges from 51 to 102 centimeters (20 to 40 inches). Elevations

range 2134 to 2927 meters (7000 to 9600 feet). Slopes range from 45 to over 80

percent, with dominant slopes 50 to 70 percent. This unit is moderately to

highly dissected by streams, with dominant stream patterns being dendritic to

parallel.

LTA Components: This landtype association consists of steep mountain slopes,

and ridge tops.

Steep mountain slopes formed in colluvium. Slopes range from 45 to +80

percent, with dominant slopes 50 to 70 percent. Soils are moderately deep to

deep. Dominant soils include Calcic Cryoborolls and Argic Cryoborolls under

mountain big sagebrush, bluebunch wheatgrass, Idaho fescue, limber pine and

lower elevation Douglas-fir series. Under subalpine fir and white-bark pine

series the dominant soils are Typic Cryoboralfs and Typic Cryochrepts. Rock

outcrops occur on 5 to 20 percent of this component. This component represents

80 percent of this unit.

Ridge tops formed in residuum. Slope gradients range 2 to 30 percent. Soils

are shallow to deep. Dominant soils are Lithic Cryoborolls and Calcic

Cryoborolls under tufted hairgrass series and alpine tundra. Under whitebark

pine series, soils are Lithic Cryochrepts and Typic Cryochrepts. Rock outcrop

occurs on 5 to 20 percent of this component. This component represents 20

percent of this map unit.

Compiled by: Annie Greene, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 266
LTA39-M332E

STEEP GLACIATED MOUNTAIN SLOPES: GNEISSES AND SCHISTS

Location: This LTA is located in the Tobacco Root Mountains of the

Beaverhead-Deerlodge National Forest in southwest Montana in the Jefferson

River Basin.

 Acreage by Subsection

 39-M332E 27,957 (Section except for M332En)

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a glaciated mountain

landscape setting, which is typically composed of cirques and troughs. Parent

materials are residuum underlain by gneiss and schist bedrock.

Accessory Characteristics: The primary soils are shallow and moderately deep

with cobbly sandy textures. The vegetation is a mosaic of rock outcrop, scree,

and coniferous forest. Mean annual precipitation ranges from 46 to 127

centimeters (18 to 50 inches). The elevation range of this LTA is 1829 to 3232

meters (6000 to 10600 feet). The dominant slopes have gradients of 60 to 100

percent. This LTA is moderately dissected by streams, with the dominant stream

pattern being trellis. Wetlands are a major component of cirque basins and

trough bottoms which are inclusions within this LTA.

LTA Components: This landtype association consists of cirques and troughs.

Cirques are formed in gneiss and schist bedrock. Slope gradients range from 60

to 100 percent. Soils on these landforms are shallow and moderately deep,

weakly developed, with cobbly sandy textures. These soils are classified as

Lithic and Typic Cryorthents and Cryochrepts. Rock outcrop and scree occur on

40 to 90 percent of this landscape component. The dominant potential natural

vegetation is subalpine fir and whitebark pine series. This component

represents 20 percent of this LTA.

Troughs are formed in gneiss and schist bedrock. Slope gradients range from 60

to 100 percent. Soils on these landforms are shallow and moderately deep,

weakly developed, with cobbly sandy textures. These soils are classified as

Lithic and Typic Cryorthents and Cryochrepts. Rock outcrop and scree occurs on

30 to 75 percent of this landscape component. The dominant potential natural

vegetation is Douglas-fir, subalpine fir, and subalpine fir-whitebark pine

series. This component represents 80 percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 267
LTA39-M332En

STEEP GLACIATED MOUNTAIN SLOPES: GNEISS

Location: This LTA is located in the Snowcrest, Greenhorn and Gravelly

mountain ranges in southwest Montana. These are drained by the Ruby and

Madison Rivers in the Jefferson River Basin.

 Acreage by Subsection

 39-M332En 7,063

LTA Setting and Characteristics:

Differentiating Characteristics: This map unit occurs in steep glaciated

mountains and is composed of cirque headwalls and glacial trough walls. Parent

material is residuum and colluvium derived from Precambrian gneiss, schist,

phyllites, amphibolites, metasedimentary rocks and minor components of gabbro

sills and marble.

Accessory Characteristics: Dominant soils are shallow to deep course sandy

loams to loams with numerous rock fragments. The vegetation varies from

shrublands, grasslands to conifers. Mean annual precipitation ranges from 51

to 102 centimeters (20 to 40 inches). Elevation ranges from 2134 to 3201

meters (7000 to 10500 feet). Slopes range from 30 to greater than 70 percent.

This unit is highly dissected by streams, with dominant stream patterns being

parallel.

LTA components: This landtype association consists of cirque headwalls and

glacial trough walls.

Cirque headwalls are steep rocky walls around a cirque basin formed by glacial

erosion. Slopes range 40 to greater than 70 percent, with dominant slopes 45

to 60 percent. Soils are shallow to moderately deep with weak development.

Numerous rock fragments are present. Dominant soils under mountain big

sagebrush and Idaho fescue series are Typic Cryoborolls. Under Douglas-fir,

subalpine fir and whitebark series; Typic Cryochrepts occur. Typic Cryumbrepts

are present under whitebark pine series and alpine tundra.

Glacial trough walls slopes of glacially eroded valleys. Slopes range from 30

to over 70 percent. with dominant slopes 40 to 60 percent. Soils are shallow

to moderately deep on upper trough walls and moderately deep to deep on lower

troughwalls. Soils are weakly developed and have numerous rock fragments.

Dominant soils under mountain big sagebrush and Idaho fescue series are Typic

Cryoborolls. Under Douglas-fir, subalpine fir series and white-bark pine

habitat types; Typic Cryochrepts occur. Typic Cryumbrepts are present under

whitebark pine series and alpine tundra.

Compiled by: Annie Greene, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 268
LTA40-M332E

LTA40-M331A

STEEP GLACIATED MOUNTAIN SLOPES: METASEDIMENTARY (BELTS)

Location: This LTA is located in the Lima Peaks, Pioneers, Beaverhead, and

Madison mountain ranges in the Beaverhead National Forest. These are located

in southwest Montana in the Jefferson and Madison Basins.

 Acreage by Section

 40-M332E 100,569

 40-M331A 626

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a steep, glacial

landscape setting which is typically composed of glacial headwalls and

troughwalls. Narrow, V-shaped trough valley bottoms and cirque basins are

described under Glaciated Mountain Slopes, LTA 50. Parent materials are

metamorphosed sediments of the Precambrian Y Belt Supergroup undifferentiated,

consisting of fine to coarse grained quartzite, siltite, argillite, carbonate,

and sandstone.

Accessory Characteristics: The primary soils are shallow, flaggy, cobbly, or

gravelly loamy sands and sandy loams. The vegetation is a mosaic of coniferous

forest, alpine turf, and rockland. Mean annual precipitation ranges from 41 to

102 centimeters (16 to 40 inches). The elevation range of this LTA is 2256 to

3231 meters (7400 to 10600 feet). The dominant slopes have gradients of 50 to

70 percent. This LTA is highly to moderately dissected with the dominant

pattern being parallel. Wetlands/seeps are a minor component of this LTA.

LTA Components: This landtype association consists of cirque headwalls, and

troughwalls. 

Headwalls are formed in metasediment bedrock. They usually have well-developed

avalanche chutes and rock glaciers/scree. Slope gradients range from 50 to 90

percent. Soils on these landforms are very shallow, weakly developed, flaggy

loamy sands and loams. These soils are classified as Lithic and Typic

Cryorthents, and Lithic and Typic Cryochrepts. Rock outcrop occurs on about

75% percent of this landscape component. The dominant potential natural

vegetation is whitebark pine, and whitebark pine-subalpine fir series. This

landform component represents about 15 percent of this LTA.

Troughwalls are formed in metasediment bedrock. They have thin to thick till

deposits, and often have developed avalanche chutes. Slope gradients range

from 45 to 70 percent. Soils on these landforms are shallow to moderately

deep, weakly to moderately developed, gravelly and cobbly loamy sands, sandy

loams, and loams. These soils are classified as Lithic and Typic Cryochrepts,

and Entic and Typic Cryumbrepts. Rock outcrop occurs on about 35 percent of

this landscape component. The dominant potential natural vegetation is

whitebark pine-subalpine fir, and subalpine fir series. This landform

component represents about 85 percent of this LTA.

Compiled by: Daniel J. Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 269
LTA41-M332E

STEEP GLACIATED MOUNTAIN SLOPES: GRANITIC

Location: This LTA is located in the Anaconda-Pintlar, Fleecer, Pioneer, Lima

Peaks, and Tobacco Root mountains in the Beaverhead/Deerlodge National Forest

These occur in southwest Montana in the Jefferson and Madison Basins.

 Acreage by Section

 41-M332E 129,472

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a steep, glacial

landscape setting which is typically composed of glacial headwalls and

troughwalls. Narrow, V-shaped trough valley bottoms and cirque basins are

described under glaciated Mountain Slopes: Granitics, LTA 51. Parent

materials are Cretaceous to Tertiary plutonic intrusive undifferentiated,

consisting mainly of granite, quartz, monzonite, and granodiorite.

Accessory Characteristics: The primary soils are shallow to moderately deep,

stony, cobbly, and gravelly sandy loams and loams. The vegetation is a mosaic

of coniferous forest and mountain grasslands with open stands of coniferous

forest. Mean annual precipitation ranges from 46 to 102 centimeters (18 to 40

inches). The elevation range of this LTA is 2134 to 3048 meters (7000 to 10000

feet). The dominant slopes have gradients of 50 to 70 percent. This LTA is

highly to moderately dissected by streams, with the dominant pattern being

parallel. Wetlands and seeps are a minor component of this LTA. 

LTA Components: This landtype association consists of cirque headwalls and

troughwalls.

Headwalls are formed in granitic bedrock. They usually have well developed

avalanche chutes and rock glaciers/scree. Slope gradients range from 50 to 90

percent. Soils on these landforms are very shallow and shallow, weakly

developed, gravelly and cobbly loamy sands and loams. These soils are

classified as Lithic and Typic Cryorthents, and Lithic and Typic Cryochrepts.

Rock outcrop occurs on about 75 percent of this landscape component. The

dominant potential natural vegetation is whitebark pine-subalpine fir, and

subalpine fir series. This landform component represents about 15 percent of

this LTA.

Troughwalls are formed in granitic bedrock. They have thin to deep till

deposits, and often have well-developed avalanche chutes. Slope gradients

range from 45 to 70 percent. Soils on these landforms are shallow to

moderately deep, weakly to moderately developed, gravelly and cobbly loamy

sands, sandy loams, and loams. These soils are classified as Lithic and Typic

Cryochrepts. Rock outcrop occurs on about 35 percent of this landscape

component. The dominant potential natural vegetation is whitebark

pine-subalpine fir, and subalpine fir series. This landform component

represents about 85 percent of this LTA. 

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 270
LTA42-M332Ea

STEEP GLACIATED MOUNTAIN SLOPES: VOLCANICS

Location: This LTA is located in the Little Blackfoot River Drainage. This

unit serves to break out areas influenced by extrusive volcanics from those

affected by Belt Series rocks.

 Acreage by Subsection

 42-M332Ea 4,793

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in an alpine glaciated

mountainous landscape setting which is typically composed of glacial trough

walls and cirque basins and headwalls. Parent material is glacial till

underlain by weakly weathered andesite and other volcanic rocks.

Accessory Characteristics: Northerly aspects and high elevation cirques have

volcanic ash influenced surface soils. The primary soils are deep (except

where glacially scoured in the cirques) and medium to moderately fine

textured. The vegetation is a mosaic of coniferous forest and foreste d scree.

Mean annual precipitation ranges from 50 to 113 centimeters (20 to 45 inches).

The elevation range of this LTA is 1586 to 2898 meters (5200 to 9500 feet).

The dominant slopes have gradients of 25 to 90 percent. This LTA is moderately

dissected (moderately to widely spaced drainages) and weakly incised by

streams, with the dominant stream patterns being parallel and subparallel.

LTA Components: This landtype association consists of glacial trough walls,

and cirque basins and headwalls.

Glacial trough walls are formed in andesite and other volcanic rock. Slope

gradients range from 60 to 90 percent. Soils on these landforms are deep or

very deep, weakly to moderately developed, and have silt loam, cobbly silt

loam or cobbly loam surfaces and very cobbly loam subsurface layers. These

soils are classified as Typic Ustochrepts, Andic Cryochrepts and Typic

Cryoboralfs. Clay development is greater on the more moderate slopes and in

areas influenced by excess moisture. Rock outcrop occurs on about 30 percent

of this landscape component. The dominant potential natural vegetation is

Douglas-fir series on the south aspects, and subalpine fir series on north

aspects. This component represents 75 percent of this LTA.

Cirque basins and headwalls are formed in andesite and other volcanic rock.

Slope gradients range from 25 to greater than 60 percent. Soils on these

landforms range from very shallow to very deep, are weakly developed, and have

loamy surfaces and very cobbly or stony loam subsurface layers. These soils

are classified as Andic Cryochrepts and Cryoboralfs. Rock outcrop occurs on

about 65 percent of this landscape component. The dominant potential natural

vegetation in the cirque basins is subalpine fir series. The glacially scoured

headwalls are often barren or support grass/shrub vegetation. This component

represents 25 percent of this LTA.

Compiled by: Larry Laing, Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 271
LTA42-M332En

STEEP GLACIATED MOUNTAIN SLOPES: VOLCANICS

Location: This LTA is located throughout the Snowcrest and Gravelly mountain

ranges in southwest Montana. These are drained by the Ruby and Madison Rivers

in the Jefferson River Basin.

 Acreage by Subsection

 42-M332En 3,298

LTA Setting and General Characteristic:

Differentiating Characteristics: This map unit occurs in steep glaciated

mountains and is composed of cirque headwalls and glacial trough walls. Parent

material is residuum and colluvium derived from rhyolitic ash-flow tuffs,

welded tuffs, andesitic porphyry and basalts.

Accessory Characteristics: Dominant soils are shallow to deep loams with

numerous rock fragments. The vegetation varies from shrublands and grasslands

to conifers. Mean annual precipitation is 51 to 102 centimeters (20 to 40

inches). Elevation ranges from 2134 to 3201 meters (7000 to 10500 feet).

Slopes range from 30 to greater than 70 percent, with dominant slopes of 40 to

60 percent. This unit is highly dissected by streams, with dominant stream

patterns being parallel.

LTA Components: This landtype association consists of cirque headwalls, and

glacial trough walls.

Cirque headwalls are rocky steep walls around cirque basins formed by glacial

erosion. Slopes range 40 to greater than 70 percent with dominant ranges 45 to

60 percent. Soils are shallow to moderately deep with weak development.

Numerous rock fragments are present. Dominant soils are Typic Cryoborolls

under mountain big sagebrush and Idaho fescue series. Under Douglas-fir,

subalpine fir series and whitebark pine habitat types; Typic Cryochrepts are

present. Rock outcrop, rock glaciers and talus occur on 20 to 40 percent of

this component. This component represents 20 percent of this map unit.

Glacial troughwalls are formed in residuum and colluvium. Slopes range from 30

to greater than 70 percent, dominant slopes are 40 to 60 percent. Soils are

shallow to moderately deep on upper trough walls and moderately deep to deep

on lower trough walls. Soils are weakly developed and have numerousrock

fragments. Dominant soils are Typic Cryoborolls under mountain big sagebrush

and Idaho fescue series. Under Douglas-fir, subalpine fir, and white-bark pine

series Typic Cryochrepts occur. Rock outcrop, rock glaciers and talus occur on

20 percent of this component. This component represents 80 percent of the map

unit.

Compiled by: Annie Greene, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 272
LTA43-M332Eb

LTA43-M332B

STEEP GLACIATED MOUNTAIN SLOPES: CARBONATES

Location: This LTA is located in the Anaconda and Flint Ranges, and Fleecer

Mountains on the Beaverhead-Deerlodge National Forest, southwest Montana, in

the upper Clark Fork River Basin.

 Acreage by Subsection

 43-M332Eb 3,012

 43-M332B 77,618

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a glaciated mountain

landscape setting, which is typically composed of cirques, troughs, and

moraines. Parent materials are residuum underlain by limestone and glacial

moraines deposited on limestone and a variety of other bedrock types.

Accessory Characteristics: The primary soils are shallow to deep with cobbly

loamy textures. The vegetation is a mosaic of grasslands, shrublands, and

coniferous forest. Mean annual precipitation ranges from 51 to 127

centimeters (20 to 50 inches). The elevation range of this LTA is 1829 to 3049

meters (6000 to 10000 feet). The dominant slopes have gradients of 25 to 80

percent. This LTA is moderately dissected by streams, with the dominant stream

pattern being parallel. Wetlands are a major component of this LTA.

LTA Components: This landtype association consists of cirques and troughs,

and moraines.

Cirques and troughs are formed in limestone bedrock. Slope gradients range

from 45 to 100 percent. Soils on these landforms are shallow and moderately

deep, weakly developed, with cobbly loamy textures. These soils are

classified as Typic and Lithic Cryorthents and Cryochrepts. Rock outcrop

occurs on 30 to 90 percent of this landscape component. The dominant potential

natural vegetation is Douglas-fir and subalpine fir series. This component

represents 40 percent of this LTA.

Moraines are composed of glacial deposits Slope gradients range from 0 to 35

percent Soils on these landforms are deep, moderately developed, with cobbly

loamy textures. These soils are classified as Typic Cryochrepts and

Cryoboralfs Rock outcrop does not occur on this landscape component. The

dominant potential natural vegetation is sagebrush, Douglas-fir, and subalpine

fir series The dominant vegetation in wetlands is willow, sedge, and

subalpine fir series. This component represents 60 percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 273
LTA43-M332E

STEEP GLACIATED MOUNTAIN SLOPES: CARBONATES

Location: This LTA is located throughout the Snowcrest and Gravelly mountains

of southwest Montana. These are drained by the Ruby and Madison Rivers in the

Jefferson River Basin.

 Acreage by Subsection

 43-M332E 6,435 (Section except for M332Eb)

LTA Setting and General Characteristic:

Differentiating Characteristics: This map unit occurs in gentle to steeply

sloping glaciated mountains and is composed of cirque headwalls, glacial

trough walls, cirque basins, moraines and trough valley bottoms. Parent

material is residuum and colluvium derived from Cretaceous, Triassic, and

Paleozoic limestones with minor amounts of interbedded calcareous shales,

Archean marbles, dolomites and associated cherts.

Accessory Characteristics: Dominant soils are shallow to deep, loams to clay

loams. Numerous rock fragments are present with stone to boulder size glacial

till. Soils with organic surfaces and organics occur in depressional areas

under sedges and moist forbs. Vegetation varies from shrublands and grasslands

to conifers. Mean annual precipitation is 51 to 102 cms (20 to 40 inches).

Elevation ranges from 2134 to 2866 (7000 to 9400 feet). Slopes range from 0 to

greater than 70 percent, with dominant slopes of 10 to 60 percent. This unit

is moderately to highly dissected by streams. The dominant stream patterns are

dendritic to parallel, depending on slope.

LTA Components: This landtype association consists of cirque headwalls glacial

trough walls, cirque basins, moraines, and trough valley bottoms.

Cirque headwalls are steep rocky walls around a cirque basin formed by glacial

erosion. Slopes range 40 to greater than 70 percent with dominant ranges being

45 to 60 percent. Soils are shallow to moderately deep with weak development.

Numerous rock fragments are present. Dominant soils are Typic Cryoborolls and

Calcic Cryoborolls under mountain big sagebrush and Idaho fescue series. 

Under Douglas-fir, subalpine fir and white-bark pine series, Typic Cryochrepts

are present. Rock outcrop, rock glaciers and talus occur on 20 to 40 percent

of this component. This component represents 15 percent of this map unit.

Glacial trough walls are slopes of glacially eroded valleys. Slopes range from

from 30 to greater than 70 percent with the dominant slopes being 40 to 60

percent. Soils are shallow to moderately deep on upper trough walls and

moderately deep to deep on lower trough walls. Soils are weakly developed and

have numerous rock fragments. Dominant soils are Typic Cryoborolls and Calcic

Cryoborolls under mountain big sagebrush and Idaho fescue series. Under

Douglas-fir, subalpine fir and white-bark pine series, Typic Cryochrepts

occur. Rock outcrop, rock glaciers and talus occur on 20 percent of this

component. This component represents 30 percent of the map unit.

Cirque basins are large hollows scooped out at the head of valleys by glacial

erosion. Soils are moderately deep to deep. Slopes range from 0 to 30 percent

with dominant slopes being 5 to 20 percent. Dominant soils include Argic

Cryoborolls and Pachic Cryoborolls under mountain big sagebrush, Idaho fescue,

and tufted hairgrass series. Histic Cryaquolls and Histosols occur under

sedge, willow and moist forb series. Typic Cryoboralfs and Typic Cryochrepts

occur under Douglas-fir, subalpine fir and white-bark pine series. Stone to

boulder size glacial till is on the surface. Rock outcrop occupies 10 to 30

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 274
percent of this component. This component represents 15 percent of this map

unit.

Moraines are undulating areas formed by glacial drift. Soils are moderately

deep to deep. Slopes range from 0 to 50 percent with dominant slopes being 5

to 35 percent. Dominant soils include Argic Cryoborolls and Pachic Cryoborolls

under mountain big sagebrush, Idaho fescue and tufted hairgrass series. 

Histic Cryaquolls and Histosols occur under sedge, willow and moist forbs. 

Typic Cryoboralfs and Typic Cryochrepts occur under Douglas-fir, subalpine

fir, and white-bark pine series. Stone to boulder size glacial till is on the

surface. Rock outcrop occupies 10 to 30 percent of this component. This

component represents 25 percent of this map unit.

Trough valley bottoms formed in glacio-fluvial sediments. Soils are deep.

Slopes range from 0 to 20 percent with dominant slopes being 5 to 15 percent.

Dominant soils include Typic Cryoborolls, Typic Cryaquolls, and Fluvents under

mountain big sagebrush, Idaho fescue and tufted haigrass series. Histic

Cryaquolls and Histosols occur under sedge, willow and moist forbs. Typic

Cryochrepts and Fluvents occur under Douglas-fir, subalpine fir and white-bark

pine series. This component represents 15 percent of this map unit.

Compiled by: Annie Greene, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 275
LTA44-M332En

STEEP GLACIATED MOUNTAIN SLOPES: SANDSTONES AND SHALES

Location: This LTA is located in the Snowcrests and Gravelly mountain ranges

in southwest Montana. These are drained by the Ruby and Madison Rivers in the

Jefferson River Basin.

 Acreage by Subsection

 44-M332En 3,894

LTA Setting and General Characteristics:

Differentiating Characteristics: This map unit occurs in a steep glaciated

mountains and is composed of cirque headwalls and glacial trough walls. Parent

material is residuum and colluvium derived from Mesozoic shales and siltstones

with minor amounts of interbedded sandstone.

Accessory Characteristics: Dominant soils are shallow to deep loams to clay

loams with numerous rock fragments. The vegetation varies from shrublands and

grasslands to conifers. Mean annual precipitation ranges from 51 to 102

centimeters (20 to 40 inches). Elevations range from 2134 to 2927 meters (7000

to 9600 feet). Slopes range from 30 to greater than 70 percent, dominant

slopes are 40 to 60 percent. This unit is highly dissected by streams, with

dominant stream patterns being parallel.

LTA Components This landtype association consists of cirque headwalls, and

trough walls.

Cirque headwalls are walls around a cirque basin formed by glacial erosion.

Slopes range 40 to greater than 70 percent with dominant slopes 45 to 60

percent. Soils are shallow to moderately deep with weak development. Numerous

rock fragments are common. Dominant soils are Typic Cryoborolls under mountain

big sagebrush and Idaho fescue series. Under Douglas-fir, subalpine fir and

whitebark pine series Typic Cryochrepts occur. Rock outcrop, rock glaciers

and talus occur on 20 to 40 percent of this component. This component

represents 20 percent of this map unit.

Glacial trough walls are slopes of glacially eroded valleys. Slopes range

from 30 to over 70 percent; dominant slopes are 40 to 60 percent. Soils are

shallow to moderately deep on upper trough walls and moderately deep to deep

on lower trough walls. Soils are weakly developed and have numerous rock

fragments. Dominant soils are Typic Cryoborolls and Calcic Cryoborolls under

mountain big sagebrush and Idaho fescue series. Under Douglas-fir, subalpine

fir and whitebark pine series Typic Cryochrepts are present. Typic Cryumbrepts

are found under whitebark pine series and alpine tundra. Rock outcrop, rock

glaciers, and talus occur on 20 to 40 percent of this component. This

component represents 80 percent of this map unit.

Compiled by: Annie Greene, Beaverhead/Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 276
LTA44-M332E

LTA44-M331A

STEEP GLACIATED MOUNTAIN SLOPES: SANDSTONES AND SHALES

Location: This LTA is located in the Pioneer, Fleecer, Lima, Tendoy, Tobacco

Root, and Madison Ranges. These are drained by the Beaverhead, Big Hole, Red

Rock, Ruby, and Madison rivers in the Jefferson and Madison Basins.

 Acreage by Section

 44-M332E 29,909 (Section except for M332En)

 44-M331A 17,976

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a steep, glacial

landscape setting which is typically composed of glacial headwalls and

troughwalls. Narrow, V-shaped trough valley bottoms and cirque basins are

described under Glaciated Mountain Slopes, LTA 53. Parent materials are

Tertiary to Cambrian sediments undifferentiated, consisting of shale,

siltstone, sandstone, limestone, and calcareous clays. Minor gypsum, chert,

and volcanic rock occurs.

Accessory Characteristics: The primary soils are shallow to deep, stony,

loams to clay loams. The vegetation is a mosaic of mountain grassland and open

coniferous forest. Mean annual precipitation ranges from 41 to 102

centimeters (16 to 40 inches). The elevation range of this LTA is 2134 to 3231

meters (7000 to 10600 feet). The dominant slopes have gradients of 25 to 70

percent. This LTA is moderately to highly dissected by streams, with the

dominant stream pattern being parallel. Wetlands/seeps are a minor component

of this LTA.

LTA Components: This landtype association consists of headwalls and

troughwalls. 

Headwalls are formed in residuum. Slope gradients range from 45 to 70

percent. Soils on these landforms are shallow to moderately deep, weakly

developed, stony loams to clay loams. These soils are classified as Typic and

Alfic Cryochrepts. Rock outcrop occurs on about 25 percent of this landscape

component. The dominant potential natural vegetation is mountain big sage,

Douglas-fir, and whitebark pine-subalpine fir series. This component

represents 15 percent of this LTA.

Troughwalls are formed in residuum. Slope gradients range from 25 to 70

percent. Soils on these landforms are shallow to moderately deep, weakly to

moderately developed, cobbly loams and clay loams. These soils are classified

as Typic and Alfic Cryochrepts, and Lithic and Typic Cryoborolls. Rock outcrop

occurs on about 15 percent of this landscape component. The dominant potential

natural vegetation is mountain big sage, Douglas-fir, and subalpine fir

series. This component represents about 85 percent of this LTA.

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 277
LTA45-M332E

LTA45-M332B

LTA45-M333D

WEAKLY GLACIATED MOUNTAIN SLOPES AND RIDGES: GRANITE

Location: This unit is located in the Bitterroot and Sapphire mountain ranges

of western Montana in the Bitterroot and Upper Clark Fork River Basins.

 Acreage by Section

 45-M332E 2,117

 45-M332B 83,690

 45-M333D 3,610

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a high elevation

broad ridgetop position which is typically composed of weakly expressed

glaciated slopes and basins that were formed by ice cap glaciers, minor valley

glaciers, and strong periglacial frost shattering. Parent materials are a

complex of frost shattered residuum and colluvium, intermixed with glacial

till derived from moderately weathered granite.

Accessory Characteristics: The primary soils are shallow to deep, coarse

soils with numerous rock fragments and have a volcanic ash surface layer. The

vegetation is a mosaic of coniferous forest, stunted wind-deformed forest, and

occasional small wet meadows. Mean annual precipitation ranges from 102 to 140

centimeters (40 to 55 inches). The elevation range is 2073 to 2743 meters

(6800 to 9000 feet). The dominant slopes have gradients of 20 to 55 percent.

This unit is slightly dissected by streams, with the dominant stream pattern

being dendritic. Wetlands and ponds are a minor component of this unit.

LTA Components: This landtype association consists of weakly developed

glacial cirques and frost shattered mountain ridge tops.

Weakly developed glacial cirques are formed in residuum, colluvium, and till

derived from a variety of rock types. Slope gradients range from 20 to 55

percent. Soils on this landform are shallow to deep and somewhat excessively

drained. These soils are weakly developed and consist of extremely bouldery

loam volcanic ash surface layers overlying very stony loamy sand substrata.

The dominant soils are classified as Lithic and Andic Cryochrepts. Rock

outcrop occurs on about 10 percent of this landscape component. The dominant

potential natural vegetation is alpine larch-subalpine fir, whitebark

pine-subalpine fir, and subalpine fir series. This component represents 65

percent of this unit.

Frost shattered mountain ridge tops are formed in residuum and colluvium.

Slope gradients range from 20 to 50 percent. Soils on this landform are

shallow to deep and somewhat excessively drained. These soils are weakly

developed and consist of very stony loam volcanic ash surface layers overlying

very cobbly coarse sandy loam substrata. The dominant soils are classified as

Lithic and Andic Cryochrepts. Rock outcrop occurs on about 15 percent of this

landscape component. The dominant potential natural vegetation is whitebark

pine-subalpine fir, alpine larch-subalpine fir, and subalpine fir series. 

This component represents 35 percent of this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 278
LTA50-M332E

GLACIATED MOUNTAIN SLOPES: METASEDIMENTARY (BELT)

Location: This LTA is located in the Highland, Beaverhead and Pioneer Ranges

on the Beaverhead/Deerlodge National Forest. These are drained by the Big Hole

and Jefferson Rivers in the Jefferson Basin.

 Acreage by Section

 50-M332E 105,881

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a gently to moderately

sloping glaciated landscape setting, which is typically composed of cirque

basins and trough bottoms, glaciated slopes, and moraine. Parent materials are

undifferentiated glacial drift, colluvium and residuum comprised of

metamorphosed sediments of the Precambrian Y Belt Supergroup undifferentiated,

consisting of fine to coarse grained quartzite, siltite, argillite, carbonate,

and sandstone.

Accessory Characteristics: The primary soils are moderately deep, somewhat

poorly drained, loams and clay loams; and shallow to moderately deep, well

drained, gravelly and cobbly sandy loams. The vegetation is a mosaic of

coniferous forest, alpine and subalpine grassland and mountain grasslands.

Mean annual precipitation ranges from 36 to 102 centimeters (14 to 40 inches).

The elevation range of this LTA is 1981 to 2987 meters (6500 to 9800 feet).

The dominant slopes have gradients of 5 to 35 percent. This LTA is variably

dissected by streams, with the dominant stream pattern being dendritic across

the glaciated slopes, to deranged in the glacial till deposits. Wetlands,

seeps, and ponds are a major component of this LTA. 

LTA Components: This landtype association consists of cirque basins and

narrow trough bottoms, glaciated slopes, and moraine.

Cirque basins and narrow trough bottoms are formed in metasediment bedrock and

relatively thin glacial deposits. Slope gradients range from 5 to 35 percent.

Soils on these landforms are very shallow to moderately deep, weakly to

moderately well developed, rocky, well-drained sandy loams and loams on upland

positions, and somewhat poorly drained loams and clay loams on lower surfaces.

These soils are classified as Lithic and Typic Cryochrepts, and Aquic and

Oxyaquic Cryochrepts. Rock outcrop occurs on about 15 percent of this

landscape component. The dominant potential natural vegetation includes

subalpine fir and sedge series. This component represents about 20 percent of

this LTA. 

Glaciated slopes are formed in metasediment residuum and relatively thin

glacial till. Slope gradients range from 10 to 40 percent. Soils on these

landforms are moderately deep, weakly to moderately developed, loams and sandy

loams. These soils are classified as Typic Cryochrepts. Rock outcrop occurs

on up to 35 percent of this landscape component. The dominant potential

natural vegetation is Douglas-fir and subalpine fir series. This component

represents about 60 percent of this LTA.

Glacial moraine is composed of metasedimentary till deposits. Slope gradients

range from 0 to 35 percent. soils on these landforms are shallow to moderately

deep, weakly to moderately developed, gravelly and stony loams and sandy

loams. These soils are classified as Dystric and Typic Cryochrepts. Rock

outcrop occurs on about 5 percent of this landscape component. The dominant

potential natural vegetation is big sagebrush, Douglas-fir, and subalpine fir

series. This component represents about 20 percent of this LTA.

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 279
LTA51-M332E

LTA51-M332D

LTA51-M331A

GLACIATED MOUNTAIN SLOPES: HARD INTRUSIVE ROCKS

Location: This unit is located in the Gallatin, Madison, and Absaroka

-Beartooth mountain ranges in southwestern Montana.

 Acreage by Section

 51-M332Ea 11,348

 51-M332Ec 2,406

 51-M332Ej 5,779

 51-M332Er 546

 51-M332D 98,649

 51-M331A 760

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit consists of gently to

moderately steep glacial moraine. Soil parent material is glacial till derived

from coarse grained, shallow intrusive rocks.

Accessory Characteristics: Vegetation is sparse to dense upper to lower

subalpine forest, Douglas-fir forest, or mountain grassland. Elevation

ranges from 1981 to 2743 meters (6500 to 9000 feet). Mean annual precipitation

is 50 to greater than 125 centimeters (20 to greater than 50 inches). Slopes

range from 0 to 40 percent.

LTA Components: This landtype association has three components:

Where vegetation is grassland, soils are Typic Cryoborolls and Argic

Cryoborolls. These soils are deep, moderately coarse to medium textured,

rocky, and have moderate fertility and water holding capacity. Rock outcrop

makes up five percent of this component. Common potential natural vegetation

include big sagebrush and Douglas-fir series. This component makes up 15

percent of the LTA.

Where vegetation is lower subalpine forest with some Douglas-fir forest, soils

are Typic Cryochrepts. These soils are moderately coarse texture, rock, and

have low fertility and water holding capacity. Rock outcrop makes up 10

percent of this component. Common potential natural vegetation is subalpine

fir and Douglas-fir series. This component makes up 50 percent of the LTA.

Where vegetation is upper subalpine forest, soils are Cryochrepts intermixed

with some Cryumbrepts. These soils are deep to moderately shallow, rocky, and

have low fertility and water holding capacity. Rock outcrop makes up 20 to 40

percent of this component. Common potential natural vegetation is subalpine

fir, whitebark pine and Idaho fescue series. This component makes up 35

percent of the LTA.

Compiled by: Henry Shovic, Gallatin National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 280
LTA51-M332E

GLACIATED MOUNTAIN SLOPES: GRANITICS

Location: This LTA is located in the Anaconda-Pintlar, Fleecer, Pioneer, and

Tobacco Root Ranges, Boulder and Highland Mountains on the Beaverhead

/Deerlodge National Forest. These are drained by the Big Hole, Beaverhead,

Jefferson and Madison rivers in the Jefferson and Madison Basins.

 Acreage by Section/Subsection

 51-M332Eb 13,668

 51-M332Ee 39,685 

 51-M332Eg 44,130

 51-M332Ek 7,918

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a gently to moderately

sloping glaciated landscape setting, which is typically composed of cirque

basins and trough bottoms, glaciated slopes, and moraine. Parent materials are

undifferentiated glacial drift, colluvium and residuum comprised of Cretaceous

to Tertiary plutonic intrusives, undifferentiated, consisting mainly of

granite, quartz, monzonite, and granodiorite.

Accessory Characteristics: The primary soils are moderately deep, somewhat

poorly drained loams and clay loams; and shallow to moderately deep, well

drained gravelly and cobbly sandy loams. The vegetation is a mosaic of

coniferous forest, alpine and subalpine grassland, and mountain grassland.

Mean annual precipitation ranges from 36 to 102 centimeters (14 to 40 inches).

The elevation range of this LTA is 1829 to 2987 meters (6000 to 9800 feet).

The dominant slopes have gradients of 5 to 35 percent. This LTA is variably

dissected by streams, with the dominant stream pattern being dendritic across

the glaciated slopes, to deranged in the glacial till deposits. Wetlands,

seeps, and ponds are a major component of this LTA.

LTA Components: This landtype association consists of cirque basins and

narrow trough bottoms, glaciated slopes, and moraine.

Cirque basins and narrow trough bottoms are formed in granitic bedrock and

relatively thin glacial deposits. Slope gradients range from 5 to 60 percent.

Soils on these landforms are very shallow to moderately deep, weakly to

moderately well developed, well drained gravelly loamy sands, sandy loams,and

loams in upland positions, and somewhat poorly drained sandy loams and

loams in depressions and bottoms. These soils are classified as Lithic and

Typic Cryochrepts, and Aquic and Oxyaquic Cryochrepts. Rock outcrop occurs on

15 percent of this landscape component. The dominant potential natural

vegetation includes subalpine fir and spruce series. This component represents

about 20 percent of this LTA.

Glaciated slopes are formed in granitic residuum and relatively thin glacial

till. Slope gradients range from 10 to 60 percent. Soils on these slopes are

moderately deep, weakly to moderately developed sandy loams, loams, and clay

loams. These soils are classified as Typic Cryochrepts. Rock outcrop occurs

on about 35 percent of this landscape component. The dominant natural

potential vegetation is Douglas-fir, subalpine fir, and whitebark

pine-subalpine fir series. This landscape component represents about 60

percent of this LTA.

Glacial moraine is comprised of granitic till deposition. Slope gradients

range from less than 2 to 35 percent. Soils on these landforms are shallow to

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 281
moderately deep, weakly to moderately developed. gravelly and stony loamy

sands, sandy loams, and loams. These soils are classified as Dystric and Typic

Cryochrepts. Rock outcrop occurs on less than 1 percent of this landscape

component. The dominant potential natural vegetation is big sagebrush,

Douglas-fir, and subalpine fir series. This landscape component represents

about 20 percent of this LTA. 

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 282
LTA53-M332En

GLACIATED MOUNTAIN SLOPES: SANDSTONES AND SHALES

Location: This LTA is located throughout the Snowcrest and Gravelly mountain

ranges and basins in southwest Montana. These are drained by the Ruby and

Madison Rivers in the Jefferson River Basin.

 Acreage by Subsection

 53-M332En 6,396

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in gentle to moderately

sloping glaciated mountains. It is composed of cirque basins, moraines and

trough valley bottoms. Parent materials Mesozoic shales and siltstones with

minor interbedded sandstone, Proterozoic shale and inclusions of quartzite and

chert.

Accessory Characteristics: Dominant soils are moderately deep to deep loams

to clay loams. Numerous rock fragments are present with cobble to stone size

glacial till on the surface. Soils with organic surfaces and organics occur in

depressional areas under sedges and moist forbs. Vegetation varies from

shrublands and grasslands to conifers. Mean annual precipitation ranges from

51 to 76 centimeters (20 to 30 inches). Elevation ranges from 2134 to 2805

meters (7000 to 9200 feet). Slopes range from 0 to 50 percent; dominant slopes

are 10 to 30 percent. This unit is moderately to highly dissected by streams,

with dominant stream patterns being dendritic. 

LTA Components: This landtype association consists of cirque basins, moraines

and trough valley bottoms.

Cirque basins are large hollows scooped out of the heads of valleys by glacial

erosion. Soils are moderately deep to deep. Slopes range 0 to 30 percen;t

with dominant slopes 5 to 20 percent. Dominant soils include Argic Cryoborolls

and Pachic Cryoborolls under mountain big sagebrush, Idaho fescue and tufted

hairgrass series. Histic Cryaquolls and Histosols occur under sedge, willow

and moist forb series. Typic Cryoboralfs and Typic Cryochrepts occur under

Douglas-fir, subalpine fir and whitebark pine series. Cobble to stone size

glacial till is on the surface. Rock outcrop occupies 10 to 30 percent of this

component. This component represents 30 percent of this map unit.

Moraines are undulating areas formed by glacial till. Soils are moderately

deep to deep. Slopes range 0 to 50 percent; with dominant slopes 5 to 35

percent. Dominant soils include Argic Cryoborolls and Pachic Cryoborolls under

mountain big sagebrush, Idaho fescue, and tufted hairgrass series. Histic

Cryaquolls and Histosols occur under sedge, willow and moist forb series.

Typic Cryoboralfs and Typic Cryochrepts occur under Douglas-fir, subalpine fir

and whitebark pine series. Cobble to stone size glacial till is on the

surface. Rock outcrop occupies 10 to 30 percent of this component. This

component represents 40 percent of this map unit.

Trough valley bottoms formed in glacial-fluvial sediments. Soils are deep.

Slopes range 0 to 20 percent, with dominant slopes 5 to 15 percent. Dominant

soils include Typic Cryoborolls, Typic Cryaquolls, and Fluvents under mountain

big sagebrush, Idaho fescue and tufted hairgrass series. Histic Cryaquolls and

Histosols occur under sedge, willow and moist forb series. Typic Cryochrepts

and Fluvents occur under Douglas-fir, subalpine fir and whitebark series. 

This component represents 20 percent of this map unit.

Compiled by: Annie Greene, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 283
LTA53-M332E

GLACIATED MOUNTAIN SLOPES: SANDSTONES AND SHALES

Location: This LTA is located in the Lima Peaks (Bitterroot Range, Beaverhead

Mountains), and Fleecer Mountains of the Beaverhead/Deerlodge National Forest

in southwest Montana. These mountains are drained by Horse Prairie, Red Rock,

Beaverhead, Big Hole, Ruby, and Madison rivers in the Jefferson and Madison

Basins.

 Acreage by Section

 53-M332E 34,575 (Section except for M332En)

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a gently to moderately

sloping glaciated landscape setting, composed of cirque basins and trough

bottoms, glaciated slopes, and moraine. Parent materials are Tertiary to

Cambrian sediments undifferentiated, consisting of shale, siltstone,

sandstone, limestone, and calcareous clays. Minor gypsum, chert, and volcanic

rock occurs.

Accessory Characteristics: The primary soils are shallow, rocky loams on

ridges; moderately deep silt loams and silty clay loams in swales. The

vegetation is a mosaic of coniferous forest, alpine and subalpine grassland,

and mountain grasslands. Mean annual precipitation ranges from 36 to 102

centimeters (14 to 40 inches). The elevation range of this LTA is 1981 to 2987

meters (6500 to 9800 feet). The dominant slopes have gradients of 5 to 30

percent. This LTA is variably dissected by streams, with the dominant stream

pattern being dendritic across the glaciated slopes, to deranged in the

glacial till deposits. Wetlands, seeps, and ponds are a major component of

this LTA.

LTA Components: This landtype association consists of cirque basins and

narrow trough bottoms, glaciated slopes, and moraine.

Cirque basins and narrow trough bottoms are formed in sandstone/shale bedrock

and relatively thin glacial deposits. Slope gradients range from 5 to 40

percent. Soils on these landforms are very shallow to moderately deep,

moderately developed, well drained gravelly sandy loams, loams, and silt loams

in the upland positions, and somewhat poorly to poorly drained sandy loams,

silt loams, and silty clay loams in depressions and bottoms. These soils are

classified as Typic Cryochrepts, Alfic Cryochrepts, Oxyaquic Cryoborolls, and

Typic Cryoboralfs. Rock outcrop occurs on about 5 percent of this landscape

component. The dominant potential natural vegetation is slender wheatgrass,

tufted hairgrass, subalpine fir, and spruce series. This component represents

20 percent of this LTA.

Glaciated slopes occur on sandstone/shale residuum and relatively thin glacial

till. Slope gradients range from 10 to 40 percent. Soils on these slopes are

moderately deep, moderately developed sandy loams, loams, and clay loams.

These soils are classified as Typic Cryochrepts, Typic Cryoborolls, and Typic

Cryoboralfs. Rock outcrop occurs on about 5 percent of this landscape

component. The dominant natural potential vegetation is subalpine fir,

whitebark pine-subalpine fir, Douglas-fir, rough fescue and big sagebrush

series. This landscape component represents about 60 percent of this LTA.

Glacial moraine is comprised of sandstone/shale till deposition. Slope

gradients range from less than 2 to 35 percent. Soils on these landforms are

moderately deep to deep, moderately developed, gravelly and stony sandy loams,

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 284
silt loams, and clay loams. These soils are classified as Typic Cryochrepts

and Typic Cryoborolls. Rock outcrop occurs on about 5 percent of this

landscape component. The dominant potential natural vegetation is big

sagebrush, Douglas-fir, and subalpine fir series. This landscape component

represents about 20 percent of the LTA.

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 285
LTA54-M332En

GLACIATED MOUNTAIN SLOPES: VOLCANICS

Location: This LTA is located throughout the Snowcrest and Gravelly mountain

ranges and basins in southwest Montana. These are drained by the Ruby and

Madison Rivers in the Jefferson River Basin.

 Acreage by Subsection

 54-M332En 678

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in gentle to moderately

sloping glaciated mountains. It is composed of cirque basins, moraines and

trough valley bottoms. Parent materials include rhyolitic ash-flow tuffs,

welded tuffs and andesite porphyry and basalt.

Accessory Characteristics: Dominant soils are moderately deep to deep loams

to clay loams. Numerous rock fragments are present with stone to boulder size

glacial till on the surface. Soils with organic surfaces and organics occur in

depressional areas under sedges and moist forbs. Vegetation varies from

shrublands and grasslands to conifers. Mean annual precipitation ranges from

51 to 76 centimeters (20 to 30 inches). Elevation ranges from 2134 to 2561

meters (7000 to 8400 feet). Slopes range from 0 to 50 percent; dominant slopes

are 10 to 30 percent. This unit is moderately to highly dissected by streams,

with dominant stream patterns being dendritic.

LTA Components: This landtype association consists of cirque basins, moraines

and trough valley bottoms.

Cirque basins are large hollows scooped out of the heads of valleys by glacial

erosion. Soils are moderately deep to deep. Slopes range from 0 to 30

percent; with dominant slopes of 5 to 20 percent. Dominant soils include

Argic Cryoborolls and Pachic Cryoborolls under mountain big sagebrush, Idaho

fescue and tufted hairgrass series. Histic Cryaquolls and Histosols occur

under sedge, willow and moist forb series. Typic Cryoboralfs and Typic

Cryochrepts occur under Douglas-fir, subalpine fir and whitebark pine series.

 Stone to boulder size glacial till is on the surface. Rock outcrop occupies

10 to 30 percent of this component. This component represents 30 percent of

this map unit.

Moraines are undulating areas formed by glacial drift. Soils are moderately

deep to deep. Slopes range 0 to 50 percent; with dominant slopes 5 to 35

percent. Dominant soils include Argic Cryoborolls and Pachic Cryoborolls under

mountain big sagebrush, Idaho fescue and tufted hairgrass series. Histic

Cryaquolls and Histosols occur under sedge, willow and moist forb series.

Typic Cryoboralfs and Typic Cryochrepts occur under Douglas-fir, subalpine fir

and whitebark pine series. Stone to boulder size glacial till is on the

surface. Rock outcrop occupies 10 to 30 percent of this component. This

component represents 40 percent of this map unit.

Trough valley bottoms formed in glacial-fluvial sediments. Soils are deep.

Slopes range 0 to 20 percent, with dominant slopes 5 to 15 percent. Dominant

soils include Typic Cryoborolls, Typic Cryaquolls, and Fluvents under mountain

big sagebrush, Idaho fescue and tufted hairgrass series. Histic Cryaquolls and

Histosols occur under sedge, willow and moist forb series. Typic Cryochrepts

and Fluvents occur under Douglas-fir, subalpine fir and whitebark pine series.

This component represents 20 percent of this map unit.

Compiled by: Annie Greene, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 286
LTA54-M332E

LTA54-M332D

GLACIATED MOUNTAIN SLOPES: VOLCANICS

Location: This LTA is located in the Boulder Mountains on the

Beaverhead-Deerlodge National Forest and the Helena National Forest. These

occur in southwest Montana in the upper Jefferson River and upper Clark Fork

River Basins.

 Acreage by Section

 54-M332E 30,482 (Section except for M332En)

 54-M332D 45,449

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a glaciated mountain

landscape setting, which is typically composed of glaciated mountain slopes

and moraines. Parent materials are glacial deposits and residuum underlain by

volcanic bedrock.

Accessory Characteristics: The primary soils range from very deep to shallow

to bedrock. They are loamy with high cobble contents especially in the

subsurface layers. The vegetation is a mosaic of coniferous forest and wet

meadows with the forest dominating. Mean annual precipitation ranges from 41

to 76 centimeters (16 to 30 inches). The elevation range of this LTA is 1677

to 2591 meters (5500 to 8500 feet). The dominant slopes have gradients of 10

to 50 percent. This LTA is highly dissected by streams, with the dominant

stream patterns being parallel or dendritic on sideslopes with a deranged

pattern locally in glacial moraines. Wetlands are a major component of this

LTA.

LTA Components: This landtype association consists of moraines and glaciated

mountain slopes.

Moraines are formed in volcanic glacial deposits. Volcanic ash affected loess

deposits often influence surface soil characteristics. Slope gradients range

from 0 to 35 percent. Soils on these landforms are very deep, moderately

developed, with cobbly loam, very cobbly loam and clay loam surface textures.

Very cobbly loams typify subsurface textures. These soils are classified as

Typic and Aquic Cryochrepts and Cryoboralfs. Rock outcrop does not occur in

this landscape component. The dominant potential natural vegetation is

Douglas-fir and subalpine fir series. Meadows in this component have soils

classified as Typic and Aquic Cryoborolls, and Typic Cryaquoll with willow,

sedge, and tufted hairgrass. This component represents 70 percent of this LTA.

Glaciated mountain slopes are formed in volcanic bedrock. Volcanic ash

affected loess deposits often influence surface soil characteristics. Slope

gradients range from 20 to 50 percent. Soils on these landforms are typically

shallow to moderately deep, weakly to moderately developed with cobbly loam or

loam surface textures. The subsurface layers are very or extremely cobbly

loams. These soils are classified as Typic and Lithic Cryochrepts and Typic

Cryoboralfs. Rock outcrop occurs on about 20 percent of this landscape

component. The dominant potential natural vegetation is subalpine fir, and

subalpine fir-whitebark pine series. This component represents 30 percent of

this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest; Larry Laing,

Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 287
LTA57-M332Ek

GLACIATED MOUNTAIN SLOPES: GNEISSES & SCHISTS

Location: This LTA is located in the Tobacco Root mountains. It is drained by

the Ruby and Madison Rivers in the Jefferson and Madison Basins.

 Acreage by Subsection

 57-M332Ek 25,943

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a gently to moderately

sloping glaciated landscape setting, which is typically composed of cirque

basins an trough bottoms, glaciated slopes, and moraine. Parent materials are

undifferentiated glacial drift, colluvium, and residuum derived from Pre-Belt

crystalline metamorphic rocks consisting of hornblende gneiss, quartzite,

metadiabase, sillimanite schist, quartz feldspar gneiss, metamorphosed granite

and migmatite.

Accessory Characteristics: The primary soils are moderately deep, somewhat

poorly drained loams and clay loams; and shallow to moderately deep, well

drained, gravelly and cobbly sandy loams. The vegetation is a mosaic of

coniferous forest, alpine and subalpine grassland, and mountain grassland.

Mean annual precipitation ranges from 36 to 102 centimeters (14 to 40 inches).

The elevation range of this LTA is about 1981 to 2987 meters (6500 to 9800

feet). The dominant slope gradient are 5 to 30 percent. This LTA is variably

dissected by streams, with the dominant stream pattern being dendritic across

the glaciated slopes, to deranged in the glacial till deposits. Wetlands,

seeps, and ponds are a significant component of this LTA. 

LTA Components: This landtype association consists of cirque basins and

narrow trough bottoms, glaciated slopes, and moraine.

Cirque basins and narrow trough bottoms are formed in gneiss/schist bedrock

and relatively thin glacial deposits. Slope gradients range from 5 to 40

percent. Soils on these landforms are very shallow to moderately deep, weakly

to moderately developed, well drained gravelly loamy sands, sandy loams, and

loams in upland positions, and somewhat poorly to poorly drained sandy 

loams, and silt loams in depressions and bottoms. These soils are classified

as Lithic and Typic Cryochrepts, and Aquic and Oxyaquic Cryochrepts. Rock

outcrop occurs on about 5 percent of this landscape component. The dominant

potential natural vegetation is subalpine fir, spruce, and sedge series. This

component of the landscape represents about 20 percent of the LTA. 

Glaciated slopes occur on gneiss/schist residuum and relatively thin glacial

till. Slope gradients range from 10 to 40 percent. Soils on these slopes are

moderately deep, weakly to moderately developed sandy loams, loams, and clay

loams. These soils are classified as Typic Cryochrepts and Typic Cryumbrepts.

Rock outcrop occurs on about 5 percent of this landscape component. The

dominant natural potential vegetation is Douglas-fir, subalpine fir, and

whitebark pine-subalpine fir series. This landscape component represents about

60 percent of this LTA.

Glacial moraine is comprised of gneiss/schist till deposition. Slope gradients

range from less than 2 to 35 percent. Soils on these landforms are shallow to

moderately deep, weakly to moderately developed, gravelly and stony loamy

sands, sandy loams, and loams. These soils are classified as Dystric and Typic

Cryochrepts. Rock outcrop occurs on about 5 percent of this landscape

component. The dominant potential natural vegetation is big sagebrush,

Douglas-fir and subalpine fir series. This landscape component represents

about 20 percent of the LTA.

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 288
LTA57-M332En

GLACIATED MOUNTAIN SLOPES: GNEISS

Location: This LTA is located throughout the Greenhorn and Gravelly mountain

ranges and basins in southwest Montana. These are drained by the Ruby and

Madison Rivers in the Jefferson River Basin.

 Acreage by Subsection

 57-M332En 6,983

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in gentle to moderately

sloping glaciated mountains. It is composed of cirque basins, moraines and

trough valley bottoms. Parent materials include Precambrian gneiss, schist,

phyllites, amphibolites, metasedimentary rocks with minor amounts of gabbro

sills and marble.

Accessory Characteristics: Dominant soils are moderately deep to deep sandy

loams to loams. Numerous rock fragments are present with stone to boulder

size glacial till on the surface. Soils with organic surfaces and organics

throughout occur in depressional areas under sedges and moist forbs. 

Vegetation varies from shrublands and grasslands to conifers. Mean annual

precipitation ranges from 51 to 76 centimeters (20 to 30 inches). Elevation

ranges 2134 to 2439 meters (7000 to 8000 feet). Slopes range 0 to 50 percent;

dominant slopes are 10 to 30 percent. This unit is moderately to highly

dissected by streams, with dominant stream pattern being dendritic. 

LTA Components: This landtype association consists of cirque basins, moraines

and trough valley bottoms.

Cirque basins are large hollows scooped out of heads of valleys by glacial

erosion. Soils are moderately deep to deep. Slopes range 0 to 30 percen; with t

dominant slopes 5 to 20 percent. Dominant soils include Argic Cryoborolls and

Pachic Cryoborolls under mountain big sagebrush, Idaho fescue and tufted

hairgrass series. Histic Cryaquolls and Histosols occur under sedge, willow

and moist forb series. Typic Cryoboralfs and Typic Cryochrepts occur under

Douglas-fir, subalpine fir and whitebark pine series. Typic Cryumbrepts occur

under whitebark pine series and alpine tundra. Stone to boulder size glacial

till is on the surface. Rock outcrop occupies 10 to 30 percent of this

component. This component represents 30 percent of this map unit.

Moraines are undulating areas formed by glacial drift. Soils are moderately

deep to deep. Slopes range 0 to 50 percent; with dominant slopes 5 to 35

percent. Dominant soils include Typic Cryoborolls and Pachic Cryoborolls under

mountain big sagebrush, Idaho fescue and tufted hairgrass series. Histic

Cryaquolls and Histosols occur under sedge, willow and moist forb series.

Typic Cryochrepts occur under Douglas-fir, subalpine fir and whitebark pine

series. Stone to boulder size glacial till is on the surface. Rock outcrop

occupies 10 to 30 percent of this component. This component represents 40

percent of this map unit.

Trough valley bottoms formed in glacial-fluvial sediments. Soils are deep.

Slopes range 0 to 20 percent, with dominant slopes 5 to 15 percent. Dominant

soils include Typic Cryoborolls, Typic Cryaquolls, and Fluvents under mountain

big sagebrush, Idaho fescue and tufted hairgrass series. Histic Cryaquolls and

Histosols occur under sedge, willow and moist forb series. Typic Cryochrepts

and Fluvents occur under Douglas-fir, subalpine fir and white-bark pine

series. This component represents 20 percent of this map unit.

Compiled by: Annie Greene, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 289
LTA60-M332E

MOUNTAIN SLOPES AND RIDGES: METASEDIMENTARY (BELT)

Location: This LTA is located in the Anaconda Pintlar, Beaverhead Mountains,

Pioneers, Fleecers, Highlands, and Lima Peaks of southwest Montana on the

Beaverhead/Deerlodge National Forest. These mountains are drained by the Big

Hole, Jefferson, Beaverhead, Red Rock, and Horse Prairie in the Jefferson

Basin.

 Acreage by Section

 60-M332E 90,807

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in an unglaciated, mountain

slope landscape setting, below the elevational zone of strong and moderate

frost shattering. This unit is typically composed of dissected slopes with

ridges and narrow, mostly ephemeral, bottoms. Parent materials are colluvium

and residuum composed of and underlain by metamorphosed sediments of

Precambrian Y Belt Supergroup undifferentiated, consisting of fine to coarse

grained quartzite, siltite, argillite, carbonate, and sandstone.

Accessory Characteristics: The primary soils are moderately deep, well

drained, dark colored sandy loams, loams, and clay loams. The vegetation is a

mosaic of coniferous forest and mountain grasslands. Mean annual precipitation

ranges from 30 to 76 centimeters (12 to 30 inches). The elevation range of

this LTA is 1981 to 2682 meters (6500 to 8800 feet). The dominant slopes have

gradients of 20 to 40 percent. This LTA is moderately to highly dissected by

streams, with the dominant stream pattern being parallel. Wetlands, lakes, and

ponds are a minor component of this LTA. 

LTA Components: This landtype association consists of slopes with rounded

ridges and narrow, steep, mostly ephemeral valley bottoms. 

Mountain slopes and ridges are formed in colluvium and residuum. Slope

gradients range from 10 to 60 percent. Soils on these landforms are moderately

deep, moderately well developed sandy loams, loams, and clay loams. These

soils are classified as Typic Cryochrepts, Typic Cryoboralfs; and Typic

Cryoborolls. Rock outcrop occurs on about 10 percent of this landscape

component. The dominant potential natural vegetation is big sagebrush, low

sagebrush, Idaho fescue, Douglas-fir, and subalpine fir series. This

component represents 98 percent of this LTA.

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 290
LTA61-M332E

LTA61-M332D

MOUNTAIN SLOPES AND RIDGES: HIGHLY WEATHERED GRANITICS

Location: This LTA is located in the Boulder, Elkhorn and Highland Mountains

on the Beaverhead-Deerlodge National Forest and the Helena National Forest in

southwest Montana. These occur in the upper Jefferson River, Prickly Pear

Creek, 10 Mile Creek and Clark Fork River Basins.

 Acreage by Section

 61-M332E 308,903

 61-M332D 251.536

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of stream dissected mountain slopes,

rolling uplands and alluvial flats. Parent materials are residuum underlain by

weathered granitic bedrock.

Accessory Characteristics: The primary soils are shallow to deep with

gravelly sandy and loamy textures. The vegetation is a mosaic of shrublands

and grasslands and coniferous forest. Small areas of aspen are common. Mean

annual precipitation ranges from 30 to 76 centimeters (12 to 30 inches). The

elevation range of this LTA is 1373 to 2591 meters (4500 to 8500 feet). The

dominant slopes have gradients of 10 to 50 percent. This LTA is moderately or

highly dissected by streams, with the dominant stream pattern being dendritic.

Wetlands are a major component in this LTA on the Deerlodge National Forest.

LTA Components: This landtype association consists of stream dissected

mountain slopes, rolling uplands, and alluvial flats.

Stream dissected mountain slopes are formed in weathered granitic bedrock.

Slope gradients range from 10 to 50 percent. Soils on these landforms are

shallow and moderately deep, weakly and moderately developed, with gravelly

sandy and loamy textures. These soils are classified as Typic and Lithic

Cryoborolls, Cryochrepts, Cryoboralfs, and Cryorthents. Rock outcrop occurs on

about 20 percent of this landscape component. The dominant potential natural

vegetation is sagebrush, Idaho fescue, Douglas-fir and subalpine fir series.

This component represents 55 percent of this LTA.

Rolling uplands are formed in moderately and weakly weathered granitics

granite-diorites and diorites. Slope gradients range from 10 to 40 percent.

Soils on these landforms are moderately deep and deep, are weakly and

moderately developed, and have sandy loam, gravelly sandy loam and loamy sand

surface soils. The subsurface layers are gravelly sandy loams, gravelly loamy

sands and loamy sands in the less developed soils and gravelly sandy clay

loams and sandy clay loams where subsoil clay accumulation occurs. 

Ustochrepts, Eutroboralfs and Haploborolls prevail at the lower elevations. 

Typic and Lithic Cryoboralfs and Cryoborolls dominate at the mid to high

elevations. Rock outcrop occurs on about 5 percent of this landscape

component. Boulders are scattered on the surface on parts of the unit. The

dominant potential natural vegetation is Douglas-fir series. Cooler aspects at

higher elevations are dominated by Douglas-fir and subalpine fir series. The

grasslands and shrublands are dominated by mountain big sagebrush and rough

fescue series. Spruce series dominates the wet forest inclusions. This

component represents 35 percent of this LTA.

Alluvial flats are formed in weathered granitic bedrock. Slope gradients range

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 291
from 0 to 15 percent. Soils on these landforms are deep, weakly developed,

with gravelly loamy textures. These soils are classified as Oxyaquic and Typic

Cryochrepts and Cryoborolls. Rock outcrop does not occur on this landscape

component. The dominant potential natural vegetation is willow, sedge, spruce,

and subalpine fir series. This component represents 10 percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest; Larry Laing,

Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 292
LTA62-M332E

LTA62-M332D

MOUNTAIN SLOPES AND RIDGES: WEAKLY WEATHERED GRANITICS

Location: This LTA is located in the Ten Mile Creek basin, the Elkhorn

Mountains, the Big Belt Mountains, and the Continental Divide Uplands.

 Acreage by Subsection

 62-M332E 949

 62-M332D 88,948

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountainous landscape

setting, which is typically composed of mountain slopes and ridges. Parent

materials are residuum and colluvium underlain by granite, granitic diorite

and diorite.

Accessory Characteristics: The primary soils have medium or moderately coarse

textured surfaces and moderately coarse and coarse textured subsurface layers.

The vegetation is a mosaic of coniferous forest and forested scree. Mean

annual precipitation ranges from 50 to 75 centimeters (20 to 30 inches). The

elevation range of this LTA is 1554 to 2438 meters (5100 to 8000 feet). The

dominant slopes have gradients of 10 to 60 percent. This LTA is mostly

undissected.

LTA Components: This landtype association consists of mountain slopes and

ridges.

Mountain slopes and ridges are formed in weakly weathered granites,

granite-diorites, and diorites. Higher elevations can have volcanic ash

influenced surface soil. Slope gradients range from 10 to 60 percent. Soils

on these landforms are extremely variable in terms of depth to bedrock,

display little to no soil development and have cobbly loam, extremely cobbly

sandy loam and extremely bouldery sand surface soils. Subsurface soils vary

also and include extremely cobbly sandy loam, very cobbly sandy loam and

extremely bouldery sand textures. These soils are mostly classified as Typic

Cryochrepts and Typic Cryorthents. Boulders are scattered about the surface in

portions of the unit. Rock outcrop and scree occurs on about 45 percent of

this landscape component. The dominant potential natural vegetation is

subalpine fir-whitebark pine series at the higher elevations with subalpine

fir and Douglas-fir series on the lower slopes. This component represents 100

percent of this LTA.

Compiled by: Larry Laing, Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 293
LTA63-M332En

MOUNTAIN SLOPES AND RIDGES: GNEISS

Location: This LTA is located throughout the Snowcrest, Gravelly, and

Greenhorn mountains in southwest Montana. These are drained by the Ruby and

Madison Rivers in the Jefferson River Basin.

 Acreage by Subsection

 63-M332En 37,136

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in non-glaciated

mountain slopes and is composed of gentle to moderate slopes. Parent

materials are colluvium and residuum derived from Precambrian gneiss, schists,

phyllites, metasedimentary rocks and minor components of gabbro sills and

marble.

Accessory Characteristics: Dominant soils are deep to very deep sandy loams

to loams with numerous rock fragments. The vegetation varies from mountain

shrublands and grasslands to conifers. Mean annual precipitation ranges from

40 to 102 centimeters (16 to 40 inches). The elevation range is from 1951 to

2866 meters (6400 to 9400 feet). The slope range is from 0 to 50 percent with

dominant slope gradients of 10 to 40 percent. This unit is slightly to

moderately dissected by streams, with dominant stream patterns being dendritic

to subparallel.

LTA Components: This landtype association consists of mountain slopes.

Mountain slopes are formed in both colluvium and residuum. Slope gradients

range from 0 to 50 percent, with 10 to 40 percent being dominant. Soils are

deep to very deep and well developed. Dominant soils include Typic Cryoborolls

under mountain big sagebrush, Idaho fescue, bluebunch wheatgrass, subalpine

for meadows and lower elevation Douglas-fir series. Under higher elevation

Douglas-fir, subalpine fir and whitebark series the dominant soils include

Typic Cryochrepts.

Compiled by: Annie Greene, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 294
LTA63-M332E

LTA63-M331A

MOUNTAIN SLOPES AND RIDGES: GNEISSES AND SCHISTS

Location: This LTA is located in the Tendoys, Tobacco Roots and Madison

Ranges in southwest Montana. Major drainages are the Red Rock, Beaverhead,

Ruby and Madison Rivers in the Jefferson Basin and Madison Basins.

 Acreage by Section

 63-M332E 73,719 (Section except for M332En)

 63-M331A 179,717

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in an unglaciated, mountain

slope landscape setting, below the elevational zone of strong and moderate

frost shattering. This unit is typically composed of dissected slopes with

ridges and narrow, mostly ephemeral, bottoms. Parent materials are colluvium

and residuum derived from Pre-Belt crystalline metamorphic rocks consisting of

hornblende gneiss, quartzite, meta-diabase, sillimanite schist,

quartz-feldspar gneiss, metamorphosed granite, and migmatite, including the

Dillon Granite-Gneiss in the Tendoy Mountains.

Accessory Characteristics: The primary soils are moderately deep, well

drained, dark colored, channery loams and fine sandy loams. The vegetation is

a mosaic of coniferous forest and mountain grassland. Mean annual

precipitation ranges from 36 to 102 centimeters (14 to 40 inches). The

elevation range of this LTA is 2042 to 2652 meters (6700 to 8700 feet). The

dominant slopes have gradients of 25 to 50 percent. This LTA is moderately to

highly dissected by streams, with the dominant stream pattern being dendritic.

Wetlands, lakes, and ponds are a minor component of this LTA. 

LTA Components: This landtype association consists of slopes with rounded

ridges and narrow, steep, mostly ephemeral valley bottoms.

Mountain slopes and ridges are formed in colluvium and residuum. Slope

gradients range from 25 to 50 percent. Soils on these landforms are moderately

deep, weakly to moderately developed, channery loams and fine sandy loams.

These soils are classified as Typic Cryochrepts and Typic Cryoborolls. Rock

outcrop occurs on about 5 percent of this landscape component. The dominant

potential natural vegetation is big sagebrush, Douglas-fir and subalpine fir

series. This landscape component represents about 98 percent of this LTA. 

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 295
LTA64-M332E

LTA64-M332D

LTA64-M331A

MOUNTAIN SLOPES AND RIDGES: VOLCANICS

Location: This LTA is located in the Boulder, Elkhorn, Fleecer, Anaconda,

Pintlar, Beaverhead, Madison, Pioneer, Lima Peaks, Tendoy, and Gallatin

Mountains on the Beaverhead-Deerlodge, Helena, and Gallatin National Forests.

These occur in southwest Montana in the upper Missouri River Basin and the

upper Little Blackfoot drainage.

 Acreage by Section

 64-M332E 216,232

 64-M332D 197,349

 64-M331A 21,460

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of stream dissected mountain slopes and

mountain ridges. Parent materials are residuum underlain by Tertiary and

Cretaceous volcanic bedrock, including andesite, dacite, rhyolite, welded and

non-welded rhyolite and felsic tuffs, and locally basalt and minor metagrabbro

dikes.

Accessory Characteristics: The primary soils are shallow, moderately deep and

deep loamy soils often with high cobble contents. The vegetation is a mosaic

of coniferous forest and shrubland/grassland, coniferous forest or

shrubland/grassland. Mean annual precipitation ranges from 38 to 75

centimeters (15 to 30 inches). The elevation range of this LTA is 1525 to 2378

meters (5000 to 7800 feet). The dominant slopes have gradients of 5 to 60

percent. The mountain slopes component of this LTA is moderately dissected by

streams with the dominant stream patterns being parallel or dendritic. The

mountain ridges are generally undissected. Wetlands are a minor component of

this LTA.

LTA Components: This landtype association consists of stream dissected

mountain slopes and mountain ridges.

Stream dissected mountain slopes are formed in colluvium and residuum over a

variety of volcanic bedrock. Some high elevation areas are influenced by

volcanic ash loess deposits. Slope gradients range from 25 to 60 percent.

Soils on these landforms are shallow, moderately deep and deep to bedrock.

They are moderately and weakly developed with cobbly and very cobbly loam

surface textures. The subsurface layers are very cobbly and extremely cobbly

loams. These soils are classified as Typic and Lithic Cryochrepts and

Cryoborolls, and Typic and Mollic Cryoboralfs. Rock outcrop occurs on about 10

percent of this landscape component. The dominant potential natural vegetation

is Douglas-fir and subalpine fir series. This component represents 50 percent

of this LTA.

Mountain ridges are formed in residuum and colluvium over a variety of

volcanic bedrock. Some high elevation areas are influenced by volcanic ash

loess deposits. Included in this component is rolling uplands found in the

eastern portion of the Elkhorns. Slope gradients range from 10 to 40 percent.

 Soils on these landforms are mostly moderately deep and shallow to bedrock. 

They are moderately and weakly developed with cobbly, stony and very cobbly

loam or loam surface textures. The subsurface layers are very cobbly, very

stony, extremely cobbly and extremely stony loams and clay loams. These soils

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 296
are mostly classified as Typic and Lithic Cryochrepts on forested sites and

Argic and Lithic Cryoborolls on grassland/shrublands. Rock outcrop occurs on

about 10 percent of this landscape component. The dominant potential natural

vegetation is rough fescue, big sagebrush, Douglas-fir, and subalpine fir

series. This component represents 50 percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest; Larry Laing,

Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 297
LTA65-M332En

MOUNTAIN SLOPES AND RIDGES: SOFT SEDIMENTARY ROCKS

Location: This LTA is located throughout the Gravelly mountains in southwest

Montana which is drained by the Ruby and Madison Rivers in the Jefferson River

Basin.

 Acreage by Subsection

 65-M332En 15,877

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit exists adjacent and on top of

the Gravelly mountain range. The soils are formed in residuum derived from

Mesozoic and Paleozoic shales and interbedded sandstones. There are minor

amounts of limestone.

Accessory Characteristics: Dominant soils are deep to very deep fine loams to

clays. The vegetation varies from shrublands, grasslands, and subalpine

meadows to conifers. Mean annual precipitation ranges from 76 to 102

centimeters (30 to 40 inches). The elevation range is from 2621 to 2927 meters

(8600 to 9600 feet). The slope range is 0 to 30 percent, with dominant slopes

5 to 20 percent. This unit is slightly to moderately dissected by streams,

with a dendritic stream pattern.

LTA Components: This landtype association consists of gentle mountain slopes.

Gentle mountain slopes occur adjacent and on top of the mountain range. Soils

are formed in residuum derived from soft sedimentary shales and interbedded

sandstones, with minor components of limestone. Slopes range from 0 to 30

percent, with dominant slopes 5 to 20 percent. Dominant soils include Pachic

Cryoborolls and Argic Cryoborolls under mountain big sagebrush, Idaho fescue,

tufted hairgrass series and subalpine forbs. Minor amounts of Argiaquic

Cryoborolls and Histosols occur under carex series. Typic Cryoboralfs occur

under subalpine fir series and whitebark pine series. Mottles can be present

in the soil profile indicative of high water tables.

Compiled by: Annie Greene, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 298
LTA65-M332E

LTA65-M332D

MOUNTAIN SLOPES AND RIDGES: SOFT SEDIMENTARY ROCKS

Location: This LTA is located in nearly all the mountain ranges on the Lewis

and Clark (Rocky Mountain Front, Big & Little Snowies, Crazies, Castles, and

Little Belt mountains), as well as in the Fleecer and Bull Mountains in

southwest Montana on the Beaverhead-Deerlodge Forest.

 Acreage by Section

 65-M332E 17,413

 65-M332D 42,266

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs on benches, basins, ridges,

and valley sideslopes. Parent materials are soft sandstones and shales.

Accessory Characteristics: The primary soils are shallow, moderately deep and

deep, skeletal loams and sandy loams. The vegetation is coniferous forest and

fescue grassland. Mean annual precipitation ranges from 41 to 76 centimeters

(16 to 30 inches). The elevation range of this LTA is 1500 to 2439 meters

(5000 to 8000 feet). The dominant slopes have gradients of 10 to 60 percent. 

This LTA is moderately dissected with the dominant stream pattern being

dendritic. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of benches and lower

valley slopes, steep valley sideslopes, and ridges and upland flats and

basins.

Benches and lower valley slopes are formed in shale, sandstone, and alluvium.

These landforms have slope gradients that range from 0 to 25 percent. Soils on

these landforms are moderately deep and deep, well developed, and consist

mainly of clay loam and clay. The major soils are classified as Typic and

Vertic Cryoborolls. Rock outcrop occurs on 5 percent of this landscape

component. The dominant potential natural vegetation is rough fescue and

Douglas-fir series. This component represents 30 percent of this LTA.

Steep valley sideslopes are formed in shale and sandstone. These landforms

have slope gradients that range from 25 to 60 percent. Soils on these

landforms are moderately deep, weakly developed, and consist mainly of very

gravelly and cobbly loams and sandy loams. The major soils are classified as

Typic Cryoborolls and Cryoboralfs. Rock outcrop makes up less than 15 percent

of this component. The dominant potential natural vegetation is rough fescue,

subalpine fir, Douglas-fir and limber pine series. This component represents

35 percent of this LTA.

Ridges and upper slopes and basins are formed in sandstone and shale. These

landforms have slope gradients that range from 10 to 40 percent. Soils on

these landforms are extremely cobbly loams and sandy loams. The major soils

are classified as Typic and Andic Cryoborolls and Cryochrepts. Rock outcrop

makes up less than 15 percent of this LTA. The dominant potential natural

vegetation is Douglas-fir and rough fescue series. This component represents

20 percent of this LTA.

Compiled by: Richard Saunders, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 299
LTA66-M332Ea

LTA66-M332Dm

MOUNTAIN SLOPES AND RIDGES: CARBONATES

Location: This LTA is located in the Elkhorn and Highland Mountains on the

Beaverhead-Deerlodge National Forest. These are in the Jefferson River Basin

in southwest Montana.

 Acreage by Subsection

 66-M332Ea 4,501

 66-M332Dm 19,493

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of stream dissected mountain slopes.

Parent materials are residuum underlain by limestone bedrock.

Accessory Characteristics: The primary soils are shallow and moderately deep

with cobbly loamy textures. The vegetation is a mosaic of coniferous forest

and shrublands and grasslands. Mean annual precipitation ranges from 36 to 51

centimeters (14 to 20 inches). The elevation range of this LTA is 1677 to 2287

meters (5500 to 7500 feet). The dominant slopes have gradients of 10 to 50

percent. This LTA is moderately dissected by streams, with the dominant stream

pattern being parallel. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of stream dissected

mountain slopes.

Stream dissected mountain slopes are formed in limestone bedrock. Slope

gradients range from 10 to 50 percent. Soils on these landforms are shallow

and moderately deep, moderately developed, and have cobbly loamy textures.

These soils are classified as Typic and Lithic Cryochrepts and Cryoboralfs;

and Argic and Lithic Cryoborolls. Rock outcrop occurs on about 15 percent of

this landscape component. The dominant potential natural vegetation is Idaho

fescue, sagebrush, Douglas-fir, and subalpine fir series. This component

represents 100 percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 300
LTA66-M332En

MOUNTAIN SLOPES AND RIDGES: CARBONATES

Location: This LTA is located throughout the Snowcrest, Gravelly, and

Greenhorn mountains in southwest Montana. These are drained by the Ruby and

Madison Rivers in the Jefferson River Basin.

 Acreage by Subsection

 66-M332En 34,857

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in non-glaciated

mountain slopes and is composed of gentle to moderate slopes. Parent

materials are colluvium and residuum derived from Cretaceous, Triassic and

Paleozoic limestones with minor amounts of interbedded calcareous shales,

Archean marbles, dolomites and associated cherts.

Accessory Characteristics: Dominant soils are deep to very deep loams to clay

loams with numerous rock fragments. The vegetation varies from shrublands and

grasslands to conifers. Mean annual precipitation ranges from 40 to 76

centimeters (16 to 30 inches). Elevation ranges from 1951 to 2866 meters (6400

to 9400 feet). Slopes range from 0 to 50 percent with dominant slope gradients

10 to 40 percent. This unit is slightly to moderately dissected by streams,

with dominant stream patterns being dendritic to subparallel.

LTA Components: This landtype association consist of mountain slopes.

Mountain slopes formed in colluvium and residuum. Slopes range from 0 to 50

percent, with 10 to 40 percent being dominant. Soils are deep to very deep and

well developed. Dominant soils include Calcic Cryoborolls under mountain big

sagebrush, Idaho fescue, bluebunch wheatgrass and lower elevation Dougla-fir s

series. Under higher elevation Douglas-fir, subalpine fir and whitebark pine

series the dominant soils include Typic Cryochrepts. Argic Cryoborolls and

Pachic Cryoborolls occur under tufted hairgrass series and forb subalpine

meadows.

Compiled by: Annie Greene, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 301
LTA68-M332En

MOUNTAIN SLOPES AND RIDGES: SANDSTONES AND SHALES

Location This LTA is located throughout the Snowcrests and Gravelly Mountain

Ranges in southwest Montana. These are drained by the Ruby and Madison Rivers

in the Jefferson River Basin.

 Acreage by Subsection

 68-M332En 56,509

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in non-glaciated gentle

to moderate slopes. Parent material is colluvium and residuum derived from

Mesozoic shales and siltstones with minor amounts of interbedded sandstone,

Proterozoic shale and inclusions of quartzite and chert.

Accessory Characteristics: Dominant soils are deep to very deep loamy to fine

soils with minimal rock fragments. The vegetation varies from mountain

shrublands and grasslands to conifers. Mean annual precipitation ranges from

40 to 76 centimeters (16 to 30 inches). The elevation range is from 1890 to

2927 meters (6200 to 9600 feet). Slopes range from 0 to 50 percent, with

dominant slope gradients 10 to 40 percent. This unit is slightly to

moderately dissected by streams, with dominant stream patterns being

dendritic.

LTA Components: This landtype association consists of mountain slopes.

Mountain slopes are formed in both colluvium and residuum. Slope gradients

range from 0 to 50 percent, with dominant slope gradients 10 to 40 percent.

Soils are deep to very deep and well developed. Dominant soils include

Argic Cryoborolls, Typic Cryoborolls and Calcic Cryoborolls under mountain big

sagebrush, Idaho fescue, bluebunch wheatgrass, tufted hairgrass, limber pine

and Douglas-fir series. Dominant soils are Typic Cryochrepts under subalpine

fir and whitebark pine series.

Compiled by: Annie Greene Beaverhead-DeerLodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 302
LTA68-M332E

LTA68-M331A

MOUNTAIN SLOPES AND RIDGES: SANDSTONES AND SHALES

Location: This LTA is located in the Lima Peaks (portion of Beaverhead

Range), Tendoy, Pioneers, Fleecer, Tobacco Roots, and Madison Range in

southwest Montana. They occur on the Beaverhead-Deerlodge National Forest in

the Jefferson and Madison River Basins.

 Acreage by Section

 68-M332E 205,962 (Section except for M332En)

 68-M331A 152,581

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in an unglaciated, mountain

slope landscape setting below the elevational zone of strong and moderate

frost shattering. This unit is typically composed of dissected slopes with

ridges and narrow, mostly ephemeral, bottoms. Parent materials are Tertiary to

Cambrian sediments undifferentiated, consisting of shale, siltstone,

sandstone, limestone, and calcareous clays. Minor gypsum, chert, and volcanic

rock occurs.

Accessory Characteristics: The primary soils are moderately deep, loams, clay

loams and silty clays. The vegetation is a mosaic of mountain grasslands and

coniferous forests. Mean annual precipitation ranges from 41 to 91

centimeters (16 to 36 inches). The elevation range of this LTA is 1829 to 2682

meters (6000 to 8800 feet). The dominant slopes have gradients of 15 to 50

percent. This LTA is moderately to highly dissected by streams, with the

dominant stream pattern being parallel, but deranged in secondary mass wasting

areas. Wetlands are a major component of this LTA. 

LTA Components: This landtype association consists of slopes with rounded

ridges and narrow, steep, mostly ephemeral valley bottoms.

Mountain slopes and ridges are formed in colluvium-alluvium and residuum of

shale and sandstone parent materials. Slope gradients range from 15 to 50

percent. Soils on these landforms are moderately deep, moderately to highly

developed, dark colored, clay loams, silty clays, and sandy loams and loams.

These soils are classified as Argic Pachic Cryoborolls, Typic Cryoborolls, and

Mollic and Typic Cryoboralfs. Rock outcrop occurs on less than 5 percent of

this landscape component. The dominant potential natural vegetation is big

sagebrush, Idaho fescue, tufted hairgrass, and Douglas-fir series. This

component represents 100 percent of this LTA. 

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 303
LTA69-M332E

LTA69-M331A

PEDIMENTS: MIXED GEOLOGY

Location: This LTA is located in the Lima Peaks (Beaverhead Mountains),

Tendoys, and southern Madison Range in southwest Montana in the Jefferson and

Madison Basins.

 Acreage by Section

 69-M332E 2,408

 69-M331A 412

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in an unglaciated, mountain

slope landscape setting below the elevational zone of strong and moderate

frost shattering. This unit is typically comprised of relatively undissected

sloping and gently sloping straight to slightly concave slopes, often with a

thin veneer of colluvium. Parent materials are mixed sedimentary,

predominantly Cretaceous sediments consisting of shale, siltstone, sandstone,

and subordinate conglomerate, limestone, and carbonaceous material, and

including minor volcanic rock. The colluvial veneer is apparently Quaternary

aged deposits.

Accessory Characteristics: The primary soils are shallow, well drained,

gravelly loams. The vegetation is a mosaic of mountain grassland and

coniferous forest. Mean annual precipitation ranges from 36 to 61 centimeters

(14 to 24 inches). The elevation range of this LTA is 2042 to 2347 meters

(6700 to 7700 feet). The dominant slopes have gradients of less than 20

percent. This LTA is weakly dissected by streams, with the dominant stream

pattern being parallel. Wetlands, lakes, and ponds are absent in this LTA. 

LTA Components: This landtype association consists of relatively long,

smooth, straight to slightly concave slopes.

Pediment slopes are formed in residuum of shale, sandstone, and limestone

parent material. Slope gradients range from less than 10 to 20 percent.

Soils on these landforms are shallow, moderately developed, gravelly loams.

These soils are classified as Lithic Calciborolls and Typic Calciborolls. 

Rock outcrop typically does not occur on this landscape component. The

dominant potential natural vegetation is big sagebrush series. This component

represents 100 percent of this LTA.

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 304
LTA70-M332E

LTA70-M332D

FROST SHATTERED MOUNTAIN RIDGE TOPS: METASEDIMENTARY (BELT)

Location: This LTA is located in the Fleecer, Highlands, Anaconda-Pintlar,

Pioneer, Beaverhead, Tendoy, and Lima Peaks (Beaverhead Mountains) ranges.

These occur in southwest Montana on the Beaverhead/Deerlodge National Forest

in the Jefferson and Madison River Basins.

 Acreage by Section

 70-M332E 132,440

 70-M332D 419

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a relatively high

elevation, gently to moderately sloping, mountain landscape setting, at or

above the zone of moderate and strong frost shattering. The unit is typically

composed of frost shattered ridges and slopes, ranging from patterned ground

to soil heaving. Parent materials are colluvium and residuum from

metamorphosed sediments of the Precambrian Y Belt Supergroup,

undifferentiated, consisting of fine to coarse grained quartzite, siltite,

argillite, carbonate, and sandstone.

Accessory Characteristics: The primary soils are very shallow to moderately

deep, channery and flaggy sandy loams and loams. The vegetation is a mosaic of

alpine turf, subalpine grasslands, subalpine forest, montane coniferous

forest, and mountain grassland. Mean annual precipitation ranges from 36 to

127 centimeters (14 to 50 inches). The elevation range of this LTA is 2134 to

3353 meters (7000 to 11000 feet). The dominant slopes have gradients of 25 to

50 percent. This LTA is slightly dissected by streams, with the dominant

stream pattern being dendritic. Wetlands, lakes and ponds are a minor

component of this unit. Some glaciated areas are included in this unit, but

frost shattering has become a dominant landform process since glaciation. 

LTA Components: This landtype association consists of frost shattered slopes

and ridges. 

Frost shattered slopes and ridges are formed in colluvium and residuum derived

from metasediment rocks comprised mostly of quartzite, siltite, and argillite.

Slope gradients range from 5 to 70 percent. Soils on these landforms are very

shallow to moderately deep, weakly to moderately developed, stony loamy sands,

sandy loams, and loams. These soils are classified as Typic and Alfic

Cryorthents, and Alfic, Dystric, and Typic Cryochrepts. Rock outcrop occurs on

about 15 percent of this landscape component. In the Highland Mountains, up to

50 percent of the unit is scree. The dominant potential natural vegetation is

sedge, Idaho fescue, subalpine fir, whitebark pine-subalpine fir, and big

sagebrush series. This component represents 98 percent of this LTA.

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 305
LTA71-M332E

FROST SHATTERED MOUNTAIN RIDGE TOPS: HIGHLY WEATHERED GRANITICS

Location: This LTA is located in the Lima Peaks, Beaverhead (including

Anaconda-Pintlar), Pioneers, Fleecers, and Tobacco Root Mountains in southwest

Montana in the Jefferson and Madison River Basins.

 Acreage by Section

 71-M332E 82,959

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a relatively high

elevation, gently to moderately sloping mountain landscape setting, at or

above the zone of moderate and strong frost shattering. The unit is typically

composed of frost shattered ridges and slopes, ranging from patterned ground

to soil heaving. Parent materials are colluvium and residuum from granite,

quartz, monzonite, and granodiorite.

Accessory Characteristics: The primary soils are very shallow to moderately

deep, gravelly and stony loamy sands, sandy loams, and loams. The vegetation

is a mosaic of talus, alpine turf, alpine, subalpine and montane coniferous

forest, and some mountain grasslands. Mean annual precipitation ranges from 36

to 102 centimeters (14 to 40 inches). The elevation range of this LTA is 2134

to 3048 meters (7000 to 10000 feet). The dominant slopes have gradients of 20

to 40 percent. This LTA is slightly dissected by streams, with the dominant

stream pattern being dendritic. Wetlands, lakes and ponds are a minor

component of this LTA. 

LTA Components: This landtype association consists of frost shattered slopes

and ridges.

Frost shattered slopes and ridges are formed in colluvium and residuum derived

from granitic rocks. Slope gradients range from 5 to 50 percent. Soils on

these landforms are very shallow to moderately deep, weakly developed,

excessively to well drained, gravelly and channery loamy sands, sandy loams

and loams. These soils are classified as Lithic Cryorthents, Typic

Cryorthents, Lithic Cryochrepts, and Typic Cryochrepts. Rock outcrop occurs on

about 20 percent of this landscape component. The dominant potential natural

vegetation is white dryad, sedge, whitebark pine-subalpine fir, subalpine fir

series. This component represents 98 percent of this LTA.

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 306
LTA72-M332E

LTA72-M332D

LTA72-M331A

FROST SHATTERED MOUNTAIN RIDGE TOPS: WEAKLY WEATHERED GRANITICS

Location: This unit is located in the Gallatin, Madison, Absaroka-Beartooth

mountain ranges in southwestern Montana. Included are the Crazy Mountains,

Bridger Mountains, Anaconda Mountains and Continental Divide uplands.

 Acreage by Section/Subsection:

 

 72-M332E 838

 72-M331A 25,079

 72-M332Dc 1,571

 72-M332Dp 106

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit consists of rounded ridgetops

with weak stream dissection. Soil parent material is frost shattered glacial

till and colluvium derived from hard crystalline rocks such as granite.

Accessory Characteristics: Vegetation is alpine turf or sparse to dense upper

subalpine and lower subalpine forest. Elevation ranges from 1981 to 2987

meters (6500 to 9800 feet). Mean annual precipitation is greater than 125

centimeters (50 inches). Slope ranges from 0 to 20 percent.

LTA Components: This landtype association has two components:

Soils on rounded ridgetops in forest are Typic and Dystric Cryochrepts. They

are deep, moderately coarse textured, rocky, and have low fertility and water

holding capacity. Rock outcrop makes up five percent of this component. The

dominant potential natural vegetation is the subalpine fir, and subalpine

fir-whitebark pine series. his component makes up 70 percent of this LTA.

Soils on rounded ridgetops with alpine turf are Dystric Cryochrepts. They are

moderately deep, coarse textured, rocky, and have low fertility and water

holding capacity. Rock outcrop makes up 20 percent of this component. A

common potential natural vegetation series is Idaho fescue. This component

makes up 30 percent of this LTA.

Compiled by: Henry Shovic, Gallatin National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 307
LTA73-M332En

FROST SHATTERED MOUNTAIN RIDGE TOPS: VOLCANICS

Location: This LTA is located throughout the Snowcrest, Gravelly, and

Greenhorn mountains in southwest Montana. These are drained by the Ruby and

Madison Rivers in the Jefferson River Basin.

 Acreage by Subsection

 73-M332En 1,723

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in non-glaciated

mountain slopes and is composed of mountain ridge tops. Parent materials are

residuum derived from rhyolitic ash-flows tuffs, welded tuffs, andesitic

porphyry and basalt.

Accessory Characteristics: Dominant soils are shallow to moderately deep

loams to clay loams with numerous rock fragments. The vegetation varies from

subalpine meadows, conifers to alpine tundra. Mean annual precipitation

ranges from 51 to 76 centimeters (20 to 30 inches). The elevation range is

from 2134 to 2561 meters (7000 to 8400 feet). The slope range is from 0 to 20

percent with dominant slope gradients of 5 to 15 percent. This unit is

slightly dissected by streams, with dominant stream pattern being dendritic.

LTA Components: This landtype association consists of mountain ridge 

tops.

Mountain ridge tops are formed in residuum. Slope gradients range from 0 to 20

percent, with dominant slopes of 5 to 15 percent. Soils are shallow to

moderately

deep. Dominant soils include Typic Cryoborolls and Typic Cryochrepts under

tufted hairgrass series, subalpine forbs, alpine tundra and whitebark pine

series. Rock outcrop occurs on 5 to 20 percent of this unit.

Compiled by: Annie Greene. Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 308
LTA73-M332E

LTA73-M332D

FROST SHATTERED MOUNTAIN RIDGE TOPS: VOLCANICS

Location: This LTA is located in the Fleecer, Boulder, Elkhorn, and

Anaconda-Pintlar (Beaverhead Mountains) Ranges on the Beaverhead/Deerlodge

National Forest. These occur in southwest Montana in the Jefferson and

Madison

River Basins.

 Acreage by Section

 73-M332E 12,383 (Section except for M332En)

 73-M332D 23,449

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a relatively high

elevation, gently to moderately sloping mountain landscape setting at or above

the zone of moderate and strong frost shattering. The unit is typically

composed of frost shattered ridges and slopes, ranging from patterned ground

to soil heaving. Parent materials are colluvium and residuum from mostly

Tertiary volcanic rocks and volcaniclastic rocks, including andesite, dacite,

and rhyolite, welded and non-welded tuffs, and locally minor metagabbro dikes.

Accessory Characteristics: The primary soils are shallow to moderately deep,

channery loams and sandy loams. The vegetation is mostly subalpine coniferous

forest. Mean annual precipitation ranges from 41 to 76 centimeters (16 to 30

inches). The elevation range of this LTA is 2134 to 2896 meters (7000 to 9500

feet). The dominant slopes have gradients of 5 to 20 percent. This LTA is

weakly dissected by streams, with the dominant stream pattern being dendritic,

or is undissected. Wetlands, lakes, and ponds are a minor component of this

LTA. 

LTA Components: This landtype association consists of frost shattered slopes

and ridges.

Frost shattered slopes and ridges are formed in colluvium and residuum derived

from volcanic rocks comprised mostly of rhyolite, welded tuffs, and andesite.

Slope gradients range from 5 to 50 percent. Soils on these landforms are

shallow to moderately deep, weakly to moderately developed, well drained

channery loams and sandy loams and extremely cobbly loams. These soils are

classified as Lithic and Typic Cryoboralfs, Lithic and Typic Cryochrepts, and

Typic Cryoborolls. Rock outcrop occurs on about 10 percent of this landscape

component. On the Helena NF, up to 25 percent of the unit is scree. The

dominant potential natural vegetation is whitebark pine-subalpine fir,

subalpine fir, rough fescue, and Idaho fescue series. This component

represents 100 percentof this LTA.

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 309
LTA74-M332En

FROST SHATTERED MOUNTAIN RIDGE TOPS: SANDSTONES AND SHALES

Location: This LTA is located throughout the Snowcrest, Gravelly, and

Greenhorn mountains in southwest Montana. These are drained by the Ruby and

Madison Rivers in the Jefferson River Basin.

 Acreage by Subsection

 74-M332En 464

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in non-glaciated

mountain slopes and is composed of mountain ridge tops. Parent materials are

residuum derived from Mesozoic shales and siltstones with minor amounts of

interbedded sandstones.

Accessory Characteristics: Dominant soils are shallow to moderately deep

loams to clay loams with numerous rock fragments. The vegetation varies from

subalpine meadows, alpine tundra to conifers. Mean annual precipitation ranges

from 76 to 102 centimeters (30 to 40 inches). The elevation range is from 2561

to 2866 meters (8400 to 9400 feet. The slope range is from 0 to 20 percent

with dominant slope gradients of 5 to 15 percent. This unit is slightly 

dissected by streams, with dominant stream pattern being dendritic.

LTA Components: This landtype association consists of mountain ridge tops.

Mountain ridge tops are formed in residuum. Slope gradients range from 0 to 20

percent, with dominant slopes of 5 to 15 percent. Soils are shallow to

moderately

deep. Dominant soils include Typic Cryoborolls and Typic Cryochrepts under

tufted hairgrass series, subalpine forbs, alpine tundra and whitebark pine

series. Rock outcrop occurs on 5 to 20 percent of this unit.

Compiled by: Annie Greene, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 310
LTA74-M332E

LTA74-M332D

LTA74-M331A

FROST SHATTERED MOUNTAIN RIDGE TOPS: SANDSTONES AND SHALES

Location: This LTA is located in the Pioneers, Fleecers, Beaverhead

Mountains, Tendoys, Tobacco Root, and Madison Ranges in southwest Montana in

the Jefferson and Madison Basins.

 Acreage by Section

 74-M332E 70,884 (Section except for M332En)

 74-M332D 859

 74-M331A 10,729

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a relatively high

elevation, gently to moderately sloping mountain landscape setting, at or

above the zone of moderate and strong frost shattering. The unit is typically

composed of frost shattered ridges and slopes, ranging from patterned ground

to soil heaving. Parent materials are colluvium and residuum from Tertiary

sediments consisting of shale, siltstone, sandstone, limestone, and calcareous

clays. Minor gypsum, chert, and volcanic rocks occur.

Accessory Characteristics: The primary soils are very shallow to moderately

deep silt loams, loams and clay loams. The vegetation is a mosaic of alpine

turf, alpine and subalpine coniferous forest, and mountain grasslands. Mean

annual precipitation ranges from 41 to 127 centimeters (16 to 50 inches). The

elevation range of this LTA is 2286 to 3048 meters (7500 to 10000 feet). The

dominant slopes have gradients of 10 to 40 percent. This LTA is slightly

dissected by streams, with the dominant stream pattern being dendritic.

Wetlands, lakes, and ponds are a minor component of this LTA.

LTA Components: This landtype association consists of frost shattered ridges

and slopes. 

Frost shattered ridges and slopes are formed in colluvium and residuum derived

from sandstones and shales. Slope gradients range from 10 to 50 percent.

Soils on these landforms are very shallow to moderately deep, weakly to

moderately well developed, silt loams, loams, and clay loams. The surface

soils can be highly organic above 9000 feet (2743 meters). These soils are

classified as Lithic Cryoborolls and Typic Cryoborolls, Typic Cryochrepts, and

Mollic Cryoboralfs. Rock outcrop occurs on about 5 percent of this landscape

component. The dominant potential natural vegetation is Idaho fescue, sedge,

parry's rush, whitebark pine-subalpine fir, and Douglas-fir series. This

component represents 95 percent of this LTA.

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 311
LTA75-M332En

FROST SHATTERED MOUNTAIN RIDGE TOPS: QUARTZITES

Location: This LTA is located throughout the Snowcrest, Gravelly, and

Greenhorn mountains in southwest Montana. These are drained by the Ruby and

Madison Rivers in the Jefferson River Basin.

 Acreage by Subsection

 75-M332En 3,523

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in non-glaciated

mountain slopes and is composed of mountain ridge tops. Parent materials are

residuum derived from non-belt Paleozoic quartzites with minor amounts of

sandstone and associated cherts.

Accessory Characteristics: Dominant soils are shallow to moderately deep

course sandy loams to loams with numerous rock fragments. The vegetation

varies from subalpine meadows and conifers to alpine tundra. Mean annual

precipitation ranges from 76 to 102 centimeters (30 to 40 inches). Elevation

ranges from 2561 to 2866 meters (8400 to 9400 feet). The slope range is from 0

to 20 percent with dominant slopes 5 to 15 percent. This unit is slightly

dissected by streams, with dominant stream pattern being dendritic.

LTA components: This landtype association consists of mountain ridge tops.

Mountain ridge tops are formed in residuum. Slope gradients range from 0 to 20

percent, with dominant slopes 5 to 15 percent. Soils are shallow to moderately

deep. Dominant soils include Typic Cryumbrepts and Typic Cryochrepts under

tufted hairgrass series, subalpine forbs, alpine tundra and whitebark pine

series. Rock outcrop occurs on 5 to 20 percent of this unit.

Compiled by: Annie Greene, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 312
LTA77-M332En

FROST SHATTERED MOUNTAIN RIDGE TOPS: GNEISS

Location: This LTA is located throughout the Snowcrest, Gravelly, and

Greenhorn mountains in southwest Montana. These are drained by the Ruby and

Madison Rivers in the Jefferson River Basin.

 Acreage by Subsection

 77-M332En 222

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in non-glaciated

mountain slopes and is composed of mountain ridge tops. Parent materials are

residuum derived from Precambrian gneiss, schists, phyllites, amphibolites,

metasedimentary rocks and minor amounts of gabbro sills and marbles.

Accessory Characteristics: Dominant soils are shallow to moderately deep

course sandy loams to loams with numerous rock fragments. The vegetation

varies from subalpine meadows and conifers to alpine tundra. Mean annual

precipitation ranges from 76 to 102 centimeters (30 to 40 inches). The

elevation range is 2561 to 2866 meters (8400 to 9400 feet). The slope range is

from 0 to 20 percent with dominant slopes of 5 to 15 percent. This unit is

slightly dissected by streams, with dominant stream pattern being dendritic.

LTA components: This landtype association consists of mountain ridge tops.

Mountain ridge tops are formed in residuum. Slope gradients range from 0 to 20

percent, with dominant slopes of 5 to 15 percent. Soils are shallow to

moderately deep. Dominant soils include Typic Cryumbrepts and Typic

Cryochrepts under tufted hairgrass series, subalpine forbs, alpine tundra and

whitebark pine series. Rock outcrop occurs on 5 to 20 percent of this unit.

Compiled by: Annie Greene, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 313
LTA77-M332E

LTA77-M331A

FROST SHATTERED MOUNTAIN RIDGE TOPS: GNEISSES AND SCHISTS

Location: This LTA is located the Tobacco Root and Madison Ranges in

southwest Montana in the Jefferson and Madison Basins.

 Acreage by Section

 77-M332E 18,445 (Section except for M332En)

 77-M331A 62,911

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a relatively high

elevation gently to moderately sloping mountain landscape setting, at or above

the zone of moderate and strong frost shattering. The unit is typically

composed of frost shattered ridges and slopes, ranging from patterned ground

to soil heaving. Parent materials are colluvium and residuum from Pre-Belt

crystalline metamorphic rocks consisting of hornblende gneiss, quartzite,

meta-diabase, sillimanite schist, quartz-feldspar gneiss, metamorphosed

granite, and migmatite.

Accessory Characteristics: The primary soils are shallow to moderately deep,

channery loams and sandy loams. The vegetation is a mosaic of alpine turf,

talus, subalpine and montane coniferous forest, and mountain grasslands. Mean

annual precipitation ranges from 41 to 91 centimeters (16 to 36 inches). The

elevation range of this LTA is 2134 to 2743 meters (7000 to 9000 feet). The

dominant slopes have gradients of 20 to 40 percent. This LTA is weakly

dissected by streams, with the dominant stream pattern being dendritic.

Wetlands, lakes, and ponds are a minor component of this LTA. 

LTA Components: This landtype association consists of frost shattered ridges

and slopes. 

Frost shattered ridges and slopes are formed in colluvium and residuum derived

from gneisses and schists. Slope gradients range from 15 to 40 percent. Soils

on these landforms are moderately deep, well drained, weakly to moderately

developed, channery sandy loams. These soils are classified as Lithic and

Typic Cryoborolls, and Lithic and Typic Cryochrepts. Rock outcrop occurs on

about 10 percent of this landscape component. The dominant potential natural

vegetation is sedge, whitebark pine-subalpine fir, Douglas-fir, and subalpine

fir series. This component represents 98 percent of this LTA.

Compiled by: Dan Svoboda, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 314
LTA81-M332E

LTA81-M332D

ROLLING HILLS: WEATHERED GRANITICS

Location: This LTA is located in the Boulder and Highland Mountains on the

Beaverhead-Deerlodge National Forest in southwest Montana. It occurs in the

upper Jefferson River and Clark Fork River Basins.

 Acreage by Section:

 81-M332E 36,161 

 81-M332D 95,357

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of rolling uplands. Parent materials are

residuum and colluvium underlain by weathered granitic bedrock.

Accessory Characteristics: The primary soils are shallow to deep with

gravelly sandy and loamy textures. The vegetation is coniferous forest and a

mosaic of shrublands and grasslands and coniferous forest. Small areas of

aspen are common. Mean annual precipitation ranges from 30 to 76 cms.(12 to 30

inches). The elevation range of this LTA is 1373 to 2591 meters (4500 to 8500

feet). The dominant slopes have gradients of 5 to 30 percent. This LTA is

moderately or highly dissected by streams, with the dominant stream pattern

being parallel and dendritic. Wetlands are a major component in this LTA.

LTA Components: This landtype association consists of two landform

components: rolling uplands and alluvial flats.

Rolling uplands are formed in weathered quartz monzonite and similar

coarse-grained igneous rocks of the Boulder Batholith. Slope gradients range

from 0 to 40 percent. Soils on these landforms are shallow, moderately deep,

to deep, are weakly to moderately developed, and have sandy loam, gravelly

sandy loam and loamy sand surface soils. The subsurface layers are gravelly

sandy loams, gravelly loamy sands and loamy sands in the less developed soils

and gravelly sandy clay loams and sandy clay loams where subsoil clay

accumulation occurs. Ustochrepts, Eutroboralfs and Haploborolls prevail at the

lower elevations. Typic and Lithic Cryochrepts, Cryoboralfs and Cryoborolls

dominate at the mid to high elevations. Rock outcrop occurs on 5 to 15

percent of this landscape component. Boulders are scattered on the surface on

parts of the unit. The dominant potential natural vegetation is Idaho fescue,

sagebrush, Douglas-fir, and subalpine fir series. This component represents 80

percent of this LTA.

Alluvial flats are formed in granitic alluvium and weathered granitic bedrock.

Slope gradients range from 0 to 15 percent. Soils on these landforms are deep,

weakly developed, with gravelly loamy textures. These soils are classified as

Oxyaquic and Typic Cryochrepts and Cryoborolls. Rock outcrop does not occur

on this landscape component. The dominant potential natural vegetation is

willow, sedge, spruce, and subalpine fir series. This component represents 20

percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 315
LTA82-M332E

LTA82-M332D

ROLLING HILLS: VOLCANICS

Location: This LTA is located in the Boulder Mountains on the Beaverhead

-Deerlodge Forest in southwest Montana. It occurs in the upper Clark

Fork River basin.

 Acreage by Section

 82-M332E 6,817

 82-M332D 13,249

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of rolling hills. Parent materials are

residuum underlain by Tertiary and Cretaceous volcanic bedrock, including

andesite, rhyolite, and welded and non-welded rhyolite and felsic tuffs.

Accessory Characteristics: The primary soils are shallow, moderately deep and

deep loamy soils often with high cobble contents. The vegetation is coniferous

forest or a mosaic of coniferous forest and shrubland/grassland. Mean annual

precipitation ranges from 38 to 75 cms. (15 to 30 inches). The elevation range

of this LTA is 1525 to 2135 meters (5000 to 7000 feet). The dominant slopes

have gradients of 5 to 30 percent. This LTA is slightly to moderately

dissected by streams with the dominant stream patterns being parallel.

Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of one landform component:

rolling hills.

Rolling hills are formed in colluvium and residuum over a variety of volcanic

bedrock. Slope gradients range from 5 to 30 percent. Soils on these landforms

are shallow, moderately deep and deep to bedrock. They are moderately and

weakly developed with cobbly and very cobbly loam surface textures. The

subsurface layers are cobbly and very cobbly loams and clay loams. These

soils are classified as Typic and Lithic Cryochrepts and Cryoborolls, and

Typic and Mollic Cryoboralfs. Rock outcrop occurs on about 10 percent of this

landscape component. The dominant potential natural vegetation is Idaho

fescue, sagebrush, Douglas-fir, and subalpine fir series. This component

represents 100 percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 316
LTA83-M332En

LOW RELIEF HILLS: FINE TERTIARY SEDIMENTS

Location: This LTA is located throughout the Snowcrest and Gravelly mountain

ranges and basins. These are drained by the Ruby and Madison Rivers in the

Jefferson River Basin.

 Acreage by Subsection

 83-M332En 33,829

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in non-glaciated

mountain slopes and is composed of gentle to moderate slopes. Parent material

consists of poorly consolidated fluvial and lacustrine Tertiary sediments.

Accessory Characteristics: Dominant soils are deep to very deep, course to

fine loams. Textures are variable depending on parent material source. Rock

fragments are lacking. The vegetation varies from shrublands and grasslands to

conifers. Mean annual precipitation is from 51 to 76 centimeters (20 to 30

inches). Elevation range is from 1951 to 2561 meters (6400 to 8400 feet).

Slopes range from 5 to 50 percent with dominant slopes of 5 to 40 percent.

This unit is moderately to highly dissected by streams, with the dominant stream

pattern being dendritic to subparallel.

LTA components: This landtype association consists of mountain slopes.

Mountain slopes formed in residuum and colluvium derived from poorly

consolidated fluvial and lacustrine Tertiary sediments. Slopes range 5 to 50

percent, with dominant slopes of 5 to 40 percent. Dominant soils include Typic

Cryoborolls and Argic Cryoborolls under mountain big sagebrush, Idaho fescue

and Douglas-fir series. Under subalpine fir series there are Typic

Cryochrepts.

Compiled by: Annie Greene, Beaverhead-DeerLodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 317
LTA83-M332E

LOW RELIEF HILLS: FINE TERTIARY SEDIMENTS

Location: This LTA is located on foothills in the basin southwest of Butte

and in the Deer Lodge Valley on the Beaverhead-Deerlodge National Forest. It

occurs in southwest Montana in the upper Jefferson and Clark Fork River

Basins.

 Acreage by Section

 83-M332E 118,120 (Section except for M332En)

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a foothill landscape

setting, which is typically composed of old terraces. Parent materials are

residuum underlain by Tertiary sedimentary rocks.

Accessory Characteristics: The primary soils are moderately deep with loamy

and clayey textures. The vegetation is a mosaic of shrublands and grasslands.

Mean annual precipitation ranges from 41 to 46 centimeters (16 to 18 inches).

The elevation range of this LTA is 1768 to 1829 meters (5800 to 6000 feet).

The dominant slopes have gradients of 0 to 35 percent. This LTA is moderately

dissected by streams, with the dominant stream pattern being parallel.

Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of old terraces.

Old terraces are formed in Tertiary sedimentary rocks. Slope gradients range

from 0 to 35 percent. Soils on these landforms are moderately deep, well

developed, with loamy and clayey textures. These soils are classified as

Typic Argiborolls. Rock outcrop generally is not found in this landscape

component. The dominant potential natural vegetation is Idaho fescue, rough

fescue, and sagebrush series. This component represents 100 percent of this

LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 318
LTA88-M332En

LOW RELIEF HILLS: COARSE TERTIARY SEDIMENTS

Location: This LTA is located throughout the Snowcrest mountains and basins

in southwest Montana. This area is drained by the Ruby River in the Jefferson

River Basin.

 Acreage by Subsection

 88-M332En 22,697

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in non-glaciated

mountains composed of gentle to moderate slopes. Parent materials include

Tertiary conglomerates, with quartzite matrix and limestone, sedimentary and

undifferentiated clasts.

Accessory Characteristics: Dominant soils are deep to very deep coarse sandy

loams with numerous rock fragments. Vegetation varies from shrublands and

grasslands to conifers. Mean annual precipitation ranges from 51 to 102

centimeters (20 to 40 inches). Elevation ranges from 2992 to 4035 meters (7600

to 10200 feet). Slopes range from 20 to greater than 60 percent, with dominant

slopes 20 to 50 percent. This unit is moderately to highly dissected by

streams with the stream patterns being dendritic to subparallel.

LTA components: This landtype association consists of mountain slopes.

Mountain slopes formed in residuum and colluvium derived from Tertiary

conglomerates. Dominant soils include Calcic Cryoborolls and Typic Cryoborolls

under mountain big sagebrush and Idaho fescue series. Under Douglas-fir,

subalpine fir and whitebark pine series Typic Cryochrepts are present. Rock

outcrop occurs on 10 to 30 percent of this unit.

Compiled by: Annie Greene, Beaverhead-DeerLodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 319
LTA90-M332Ea

MASS WASTED SLOPES: MIXED GEOLOGY

Location: This LTA is located north of Electric Peak in the Little Blackfoot

drainage of the Clark Fork basin.

 Acreage by Subsection

 90-M332Ea 4,492

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a mountainous landscape

setting, which is typically composed of mountain slopes and ridges. Parent

materials are old landslide deposits underlain by volcanic rock.

Accessory Characteristics: The primary soils are very deep and have clayey

subsoils. The vegetation is coniferous forest. Mean annual precipitation

ranges from 50 to 63 centimeters (20 to 25 inches). The elevation range of

this LTA is 1799 to 2012 meters (5900 to 6600 feet). The dominant slopes have

gradients of 10 to 40 percent. This LTA is moderately to highly dissected by

streams, with the dominant stream pattern being deranged. Wetlands are a major

component of this LTA.

LTA Components: This landtype association consists of landslides.

Landslides are formed in landslide deposits associated with volcanic bedrock.

Slope gradients range from 10 to 40 percent. Soils on these landforms are very

deep and well developed. They have moderately fine textured surface layers

and high subsoil clay accumulations. They typically have silty clay loam

surface textures. Subsoils are silty clay loam and silty clay with more than

35 percent rock (mostly gravel and cobble). These soils are classified as

Mollic Cryoboralfs. Inclusions of Typic Cryaquolls are in bogs. The dominant

potential natural vegetation is subalpine fir, spruce and Douglas-fir.

Compiled by: Larry Laing, Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 320
LTA90-M332Eb

MASS WASTED SLOPES: MIXED GEOLOGY

Location: This LTA is located near Fleecer Ridge on the Beaverhead-Deerlodge

National Forest in southwest Montana in the upper Jefferson River Basin.

 Acreage by Subsection/Subsection

 90-M332Eb 3,901

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting and is composed of slumps and landflows. Parent materials are slump

and landflow deposits underlain by siltstone and shale bedrock.

Accessory Characteristics: The primary soils are deep with loamy and clayey

textures. The vegetation is a mosaic of mountain grasslands and coniferous

forest. Mean annual precipitation ranges from 46 to 51 centimeters (18 to 20

inches). The elevation range of this LTA is 1829 to 2287 meters (6000 to 7500

feet). The dominant slopes have gradients of 10 to 35 percent. This LTA is

moderately dissected by streams. The dominant stream pattern is parallel with

local deranged areas. Wetlands are a major component of this LTA.

LTA Components: This landtype association consists of slumps and landflows.

Slumps and landflows are formed in siltstone and shale bedrock. Slope

gradients range from 10 to 45 percent. Soils on these landforms are deep,

moderately developed, with loamy and clayey textures. These soils are

classified as Argic Cryoborolls and Typic Cryoboralfs. Rock outcrop occurs on

about 5 percent of this landscape component. The dominant potential natural

vegetation is Douglas-fir and subalpine fir series. This component represents

100 percent of this LTA.

Compiled by: Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 321
LTA90-M332En

MASS WASTED SLOPES: MIXED GEOLOGY

Location: This LTA is located throughout the Snowcrests and Gravelly mountains

and basins in southwest Montana. This area is drained by the Ruby and Madison

Rivers in the Jefferson River Basin.

 Acreage by Subsection

 90-M332En 73,061

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in both glaciated and

non-glaciated mountain areas. These units occur in soft sediments and also

include collapsed glacial deposits in soft sediments. Landflows are

characterized by undulating or steep micro-relief and indications of recent

movement, such as slip scars, cracks or leaning trees. Landflows have many

seeps, springs and depressions often containing small ponds or bogs. The

drainage pattern is deranged, so runoff and groundwater collect in

depressions.

Accessory Characteristics: Soils are deep to very deep coarse sandy loams to

clays depending on parent material. Course fragments can be present. The

vegetation is often mosaic with mixed grassland, shrubland and conifers.

Aspens, sedges, wet forbs and grasses are associated with the depressional

areas and high water tables. Mean annual precipitation ranges from 41 to 102

centimeters (16 to 40 inches). The elevation range is from 1951 to 2866 meters

(6400 to 9400 feet). Slopes range from 5 to 50 percent, dominant slopes are 10

to 30 percent.

LTA Components: This landtype association consists of landflows.

Landflows (landslide deposits) formed in residuum of varying parent materials.

On Cliff Lake bench, young Tertiary unconsolidated fluvial and lacustrine

silts and sands are collapsing under recent volcanic flows. On the east side

of the Ruby River, landslides are common in heavy clays from weathered shales.

In the southwest area of the Snowcrests a conglomerate is weathering into

coarse sands and collapsing with increased slope gradients. Other landslides

are evident throughout the area. Dominant soils include Argic Pachic

Cryoborolls under mountain big sage, Idaho fescue, tufted hairgrass and aspen

series. Under Douglas-fir and subalpine fir series Typic Cryoboralfs are

common. Minor amounts of Histic Cryaquolls and Histosols occur under sedge

and willow series. Coarse fragments are common in the conglomerates and areas

of collapsing glacial till.

Compiled by: Annie Greene, Beaverhead-DeerLodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 322
LTA90-M332E

LTA90-M331A

MASS WASTING: MIXED GEOLOGY

Location: This LTA is located in the Madison, Tobacco Root, Fleecer, Pioneer,

Anaconda Pintlar, Beaverhead, Lima Peaks, and Tendoy Mountains. These are in

southwest Montana in the Jefferson and Madison River Basins.

 Acreage by Section/Subsection

 90-M332E 25,903 (Section except for M332Ea, M332Eb, M332En)

 90-M331Am 11,231

 90-M332Ap 55,734

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a foothills to mountain

landscape setting which is typically composed of deep bedrock (hundreds of

feet thick) and surficial (tens of feet thick) mass failures, both

translational and rotational. Parent materials are landslide deposits,

colluvium, and residuum derived mostly from Cretaceous and Tertiary shales and

sandstones.

Accessory Characteristics: The primary soils are deep, silty clay loams,

silty clays, and clays. The vegetation is a mosaic of subalpine coniferous

forest, montane coniferous forest, and subalpine and mountain grasslands. 

Mean annual precipitation ranges from 36 to 102 centimeters (14 to 40 inches).

The elevation range of this LTA is 2012 to 2804 meters (6600 to 9200 feet).

The dominant slopes have gradients of 20 to 35 percent. This LTA is moderately

dissected by streams, with the dominant stream pattern being deranged to

dendritic. Wetlands and small ponds are a major component of this LTA. 

LTA Components: This landtype association consists of scarp slopes and

landslide deposits.

Scarp slopes are formed in colluvium, residuum, and sometimes old glacial

deposits. Slope gradients range from 20 to 70 percent. Soils on these

landforms are very shallow to shallow, weakly developed, channery and flaggy

sandy loams, loamy fine sands, clay loams, and silty clays, and clays. These

soils are classified as Typic Cryorthents and Typic Cryochrepts. Rock outcrop

occurs on about 15 percent of this landscape component. The dominant potential

natural vegetation is tufted hairgrass, and whitebark pine- subalpine fir

series; numerous early successional forb communities and primary succession.

This component represents 10 percent of this LTA.

Landslide deposits and mountain slopes are formed in colluvium, residuum, old

landslide deposits, and sometimes old glacial deposits (Bull Lake). Slope

gradients range from 10 to 50 percent. Soils on these landforms are deep,

moderately well developed, silty clay loams, silty clays and clays. These

soils are classified as Aquic, Mollic, and Typic Cryoboralfs, Typic

Argiborolls, and Argic Pachic Cryoborolls. Rock outcrop occurs on about 5

percent of this landscape component. The dominant potential vegetation is

tufted hairgrass, whitebark pine-subalpine fir, spruce, subalpine fir, aspen,

and Idaho Fescue series. This component represents 85 percent of this

landscape component.

Compiled by: Dan Svoboda, Beaverhead-Deer Lodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 323
LTA92-M332E

LTA92-M332B

LTA92-M332D

COLLUVIAL DEPOSITS: MIXED GEOLOGY

Location: This LTA is located throughout the Helena National Forest.

 Acreage by Section

 92-M332E 3,557

 92-M332B 6,383

 92-M332D 12,928

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a mountainous landscape

setting, which is typically composed of mountain slopes and ridges. Parent

materials are colluvial deposits, in basins and on toeslopes, typically

influenced by metasedimentary and volcanic rocks.

Accessory Characteristics: The primary soils are very deep and have loamy or

clayey subsoils. The vegetation is coniferous forest. Mean annual

precipitation ranges from 38 to 75 centimeters (15 to 30 inches). The

elevation range of this LTA is 1464 to 2135 meters (4800 to 7000 feet). The

dominant slopes have gradients of 10 to 50 percent. This LTA is highly

dissected (but weakly incised) by streams, with the dominant stream pattern

being parallel or subparallel. Wetlands are a major inclusion in this LTA.

LTA Components: This landtype association consists of colluvial deposits.

Colluvial deposits are derived from metasedimentary and volcanic rock. Some

areas are also influenced by limestone colluvium. Slope gradients range from

10 to 50 percent. Soils on these landforms are very deep and weakly to well

developed. They have moderately fine textured surface layers and high subsoil

clay accumulations. They typically have very cobbly loam or cobbly silt loam

surface textures. Subsoils are very cobbly loam, clay loam or silty clay loam.

These soils are classified as Typic Cryochrepts, Typic Cryoboralfs, and Argic

Cryoborolls. Inclusions of Aquic Cryoborolls, Aquic Cryoboralfs and Typic

Cryaquepts are associated with seeps and springs. The dominant potential

natural vegetation is subalpine fir, spruce and Douglas-fir.

Compiled by: Larry Laing, Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 324
CHAPTER 10

LTA Descriptions

Section M332G Blue Mountains

This Section occurs mostly in northeast Oregon, but extends a short distance

into the Northern Region in west central Idaho. Sixteen LTAs were mapped in

this Section. See Appendix F for a complete list of LTAs and their

acreages. Map unit descriptions are preceded by the following illustrations:

 Figure 40: Map showing location of M332G within the Northern Region

 

 Figure 41: M332G landscape photograph

 Near Pittsburgh Saddle, Nez Perce National Forest

 Figure 42: Map showing distribution of LTAS within M332G

 Figure 43: Bar chart showing abundance of landform groups in M332G

 Figure 44: Bar chart showing abundance of geologic material groups in 

 M332G

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 325
LTA10-M332G

VALLEYS: RECENT COARSE ALLUVIUM

Location: This unit is located in valley bottoms along larger streams in

north central Idaho, in the Snake and Salmon River Basins.

 Acreage by Section

 10-M332G 433

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs on valley bottom

landscape settings and consists of floodplains and low terraces. Parent

materials are recent alluvial deposits derived from granite, schist,

quartzite, gneiss, basalt, or volcanics.

Accessory Characteristics: The primary soils are very deep loams or silt

loams over gravelly or cobbly sand or loamy sand substrata. The vegetation is

a mosaic of shrubland and dry coniferous forest, and grassland. Mean annual

precipitation ranges from 40 to 65 centimeters (15 to 25 inches). The

elevation range is 350 to 550 meters (1200 to 2000 feet). The dominant slopes

gradients are 0 to 10 percent. This unit is moderately dissected by stream;s

the dominant stream pattern is dendritic. Wetlands are seldom a major

component of this unit.

LTA Components: This landtype association consists of low stream terraces and

floodplains.

Low terraces and floodplains are formed in mixed coarse textured alluvium.

Slope gradients range from 1 to 10 percent. Soils on this landform are very

deep and well to moderately well drained. These soils are weakly to moderately

developed loams and silt loams over sand and gravel to cobble-sized rocks. 

The dominant soils are classified as Typic Xerofluvents. Rock outcrops do not

occur in this landscape component. The dominant potential natural vegetation

is dry coniferous forest, shrubland, and grassland.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 326
LTA12-M332G

VALLEYS: OUTWASH AND OLDER COARSE ALLUVIUM

Location: This unit is located in major river valleys in west central Idaho

in the Salmon and Snake River Basins.

 Acreage by Section

 12-M332G 5,193

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs on valley bottoms of

canyon breaks and is dominated by old high terraces. These occur with low

flood plains and alluvial fans. Parent materials are mixed alluvium underlain

by undifferentiated lithology.

Accessory Characteristics: The primary soils are very deep sands, sandy

loams, and loams over cobbles and gravels. The vegetation is a mosaic of

grassland and coniferous forest with some unvegetated cobble and sand bars.

Mean annual precipitation ranges from 51 to 64 centimeters (15 to 25 inches).

 The elevation range is 450 to 750 meters (1200 to 2500 feet). The dominant

slopes have gradients of 1 to 30 percent. This unit is adjacent to large

rivers and may be dissected by smaller streams. In low floodplains and fans,

wetlands and cobble and sand bars are numerous. 

LTA Components: This landtype association consists of older terraces,

floodplains, and alluvial fans.

Old terraces are formed in old alluvium and loess. Slope gradients range from

1 percent on terrace floors to near vertical on truncated terrace faces. Soils

on these landforms are very deep, moderately developed sandy loams and loams

with loamy substrata. These soils are classified as Calcic Haploxerolls. Rock

outcrop is uncommon. The dominant potential natural vegetation series are

bluebunch wheatgrass and ponderosa pine. This component represents 65 percent

of this unit.

Floodplains are formed in recent alluvium of mixed lithology. Slope gradients

range from 1 to 3 percent. Soils on these landforms are deep to very deep,

poorly developed stratified sands, gravels, cobbles and some fine material.

These soils are classified as cobbly Typic Xerofluvents. Rock outcrop is

uncommon. The dominant potential natural vegetation series are bluebunch

wheatgrass and ponderosa pine. This component represents 20 percent of this

unit.

Alluvial fans are formed in coarse recent alluvium at the mouth of tributary

streams. Slope gradients range from 5 to 30 percent. Soils on these landforms

are very deep, poorly developed, poorly stratified sands, gravels, cobbles and

boulders. These soils are classified as cobbly Typic Xerofluvents and

Udifluvents. Rock outcrop is uncommon. Plant communities are often dominated

by willow, cottonwood, and white alder near streams and Douglas-fir or

ponderosa pine series on drier positions. This component represents 15 percent

of this unit.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 327
LTA17-M332G

HILLS AND PLATEAUS: LOESS

Location: This unit is located in west-central Idaho on the Palouse and Camas

Prairies.

 Acreage in Section

 17-M332G 9,801

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a low to mid

elevation, gently to moderately sloping landscape setting which is typically

composed of low relief rolling hills. Parent materials are a thick layer 6+

feet) of wind-blown loess underlain primarily by Columbia flood basalts.

Accessory Characteristics: The primary soils are deep to very deep with silt

loam surface textures and silt loam to silty clay loam subsurface textures.

The vegetation is a mosaic of prairie grasslands with forest vegetation at the

higher elevations. Mean annual precipitation ranges from 38 to 76 cms. (15 to

30 inches). The elevation range is 610 to 914 meters (2000 to 3000 feet). The

dominant slopes have gradients of 0 to 30 percent. This unit is slightly to

moderately dissected by streams, with the dominant stream pattern being

dendritic. Wetlands are a minor component of this unit.

LTA Components: This landtype association consists of low relief rolling

hills.

Low relief rolling hills are formed in wind-blown loess. Slope gradients range

from 5 to 30 percent. Soils on these landforms are deep to very deep, highly

developed, and consist of silt loam surface textures and silt loam and silty

clay loam subsurface textures. These soils are classified as Ultic

Argixerolls, Ultic Haploxeralfs, and Pachic Ultic Haploxerolls. Rock outcrop

are uncommon on this landscape component. The dominant potential natural

vegetation is bluebunch wheatgrass and Idaho fescue in the prairie grasslands

and ponderosa pine, Douglas-fir, and grand fir in forested areas. This

component represents 90 percent of this unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 328
LTA22-M332G

BREAKS: MODERATELY WEATHERED GRANITICS

Location: This unit is located along streams and rivers in west central Idaho

in the Snake River Basin.

 Acreage by Section

 22-M332G 18,597

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is canyon breaks and is

composed of dissected stream breaks. Parent materials are moderately weathered

Jurassic granodiorite.

Accessory Characteristics: The primary soils are moderately deep to deep

gravelly loams and sandy loams. The vegetation is a mosaic of grassland and

coniferous forest. Mean annual precipitation ranges from 38 to 127 centimeters

(15 to 50 inches). The elevation range is 450 to 2400 meters (1500 to 8000

feet). The dominant slopes have gradients of 50 to more than 80 percent. This

unit is moderately to highly dissected by streams, with the dominant stream

pattern being parallel.

LTA Components: This landtype association consists of dissected breaks.

Breaks are formed in residuum and colluvium of granitic lithology. Soils on

these landforms are shallow to very deep, moderately developed gravelly loams

and sandy loams with very gravelly or cobbly loamy or sandy substrata. These

soils are classified as Ultic Haploxerolls, Typic Dystrochrepts, and Dystric

Cryochrepts. Rock outcrop is less than 25 percent of the unit. The dominant

potential natural vegetation series at low elevations is bluebunch wheatgrass,

at mid elevations Douglas-fir and at high elevations subalpine fir.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 329
LTA24-M332G

BREAKS: VOLCANICS

Location: This unit is located along streams and rivers in west central

Idaho.

 Acreage by Section

 24-M332G 420,518

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is in canyons and is composed

of dissected stream breaks. Parent materials are poorly to moderately

weathered Miocene basalt, Seven Devils volcanics and included limestone.

Accessory Characteristics: The primary soils are moderately deep to deep

loams and cobbly loams. The vegetation is a mosaic of grassland and coniferous

forest. Mean annual precipitation ranges from 33 to 89 centimeters (13 to 35

inches). The elevation range is 275 to 1700 meters (900 to 5500 feet). The

dominant slopes have gradients of 50 to more than 80 percent. This unit is

moderately dissected by streams, with the dominant stream pattern being

parallel. 

LTA Components: This landtype association consists of dissected breaks.

Breaks are formed in mixed volcanic ash influenced loess, residuum and

colluvium of volcanic lithology. Soils on these landforms are moderately deep

to deep, moderately developed cobbly loams and loams with loamy or clayey

substrata. These soils are classified as Ultic Argixerolls and Dystric

Cryochrepts. Rock outcrop is less than 25 percent of the unit. The dominant

potential natural vegetation at low elevations is bluebunch wheatgrass, and at

mid elevations Douglas-fir and grand fir.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 330
LTA26-M332G

BREAKS: MODERATELY WEATHERED GNEISSES, QUARTZITES AND SCHISTS

Location: This unit is located along streams and rivers in the Seven Devils

Mountains of west central Idaho in the Snake and Salmon River Basins.

 Acreage by Section

 26-M332G 29,535

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is composed of dissected

stream breaks. Parent materials are moderately weathered gneiss, quartzite,

and schist associated with the West Idaho Suture Zone.

Accessory Characteristics: The primary soils are moderately deep to deep sandy

loams and loams. The vegetation is a mosaic of grassland and coniferous

forest. Mean annual precipitation ranges from 46 to 114 centimeters (17 to 50

inches). The elevation range is 500 to 2300 meters (1600 to 7700 feet). The

dominant slopes have gradients of 50 to 80 percent. This unit is moderately

dissected by streams, with the dominant stream pattern being parallel. 

LTA Components: This landtype association consists of dissected breaks.

Breaks are formed in mixed volcanic ash influenced loess, residuum and

colluvium of felsic metamorphic lithology. Soils on these landforms are

moderately deep to very deep, moderately developed loams and sandy loams with

sandy or loamy substrata. These soils are classified as Ultic Haploxerolls,

Typic Dystrochrepts, and Dystric Cryochrepts. Rock outcrop is less than 25

percent of the unit. The dominant potential natural vegetation series at low

elevations is bluebunch wheatgrass and Idaho fescue, at mid elevations

Douglas-fir and grand fir, and at high elevations subalpine fir.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 331
LTA42-M332G

STEEP GLACIATED MOUNTAIN SLOPES: VOLCANICS

Location: This unit is located in high elevation glaciated areas of the Seven

Devils Mountains of west central Idaho in the Salmon River and Snake river

basins.

 Acreage by Section

 42-M332G 21,164

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is composed of steep glacial

trough walls and cirques. Parent materials are poorly weathered andesite and

rhyolite associated with Seven Devil's volcanics, and included limestone of

the

Martin Bridge formation.

Accessory Characteristics: The primary soils are shallow to deep gravelly

loams. The vegetation is coniferous forest with inclusions of herbaceous

dominated openings. Mean annual precipitation ranges from 76 to 127

centimeters (30 to 50 inches). The elevation range is 1200 to 2600 meters

(4000 to 8600 feet). The dominant slopes have gradients of 50 percent to near

vertical. This unit is moderately dissected by streams, with the dominant

stream pattern being parallel. Wetlands and lakes are significant inclusions

in basins and toeslopes.

LTA Components: This landtype association consists of dissected trough walls

and cirque headwalls.

Dissected troughwalls are formed in mixed volcanic ash influenced loess, till,

residuum and colluvium of volcanic and metasedimentary lithology. Slope

gradients range from 50 to 80 percent. Soils on these landforms are moderately

deep to deep, weakly developed gravelly loams and sandy loams with very cobbly

loam substrata. These soils are classified as Dystric Cryochrepts. Rock

outcrop is less than 25 percent of the unit. The dominant potential natural

vegetation series at mid elevations is grand fir, and at high elevations

subalpine fir.

Cirque headwalls are formed in till, residuum, and colluvium of volcanic and

metasedimentary lithology. Slope gradients range from 50 percent to near

vertical. Soils on these landforms are shallow to moderately deep, weakly

developed gravelly loams with cobbly loam substrata. These soils are

classified as Dystric Cryochrepts and Entic Cryumbrepts. Rock outcrop may be

50

percent of the unit. The dominant potential natural vegetation is subalpine

fir, whitebark pine/subalpine fir, and herbaceous or shrub dominated openings.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 332
LTA51-M332G

GLACIATED MOUNTAIN SLOPES: GRANITIC

Location: This unit is located in mid to high elevation glaciated areas of

the Seven Devils Mountains of west central Idaho in the Salmon and Snake River

basins.

 Acreage by Section

 51-M332G 1,459

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is composed of gently to

moderately sloping alpine glaciated lands, comprising moraines. Parent

materials are poorly weathered till, residuum, and colluvium associated with

Jurassic granite.

Accessory Characteristics: The primary soils are deep to very deep loams and

sandy loams. The vegetation is coniferous forest. Mean annual precipitation

ranges from 89 to 114 centimeters (35 to 45 inches). The elevation range is

1600 to 2200 meters (5300 to 7200 feet). The dominant slopes have gradients of

10 to 50 percent. This unit is moderately dissected by streams, with the

dominant stream pattern being pinnate. Wetlands are minor inclusions in basins

and depressions.

LTA Components: This landtype association consists of moraines.

Moraines are formed in mixed volcanic ash influenced loess and glacial till of

granitic lithology. Slope gradients range from 5 to 50 percent. Soils on

these landforms are moderately deep to very deep, weakly developed loams and

sandy loams with cobbly, loamy sand and sand substrata. These soils are

classified as Dystric Cryochrepts. Rock outcrop is less than 15 percent of the

unit. The dominant potential natural vegetation series at mid elevations is

grand fir, and at high elevations subalpine fir.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 333
LTA54-M332G

GLACIATED MOUNTAIN SLOPES: VOLCANICS

Location: This unit is located in high elevation glaciated areas of west

central Idaho in the Snake and Salmon River basins.

 Acreage by Section

 54-M332G 16,458

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is composed of gently to

moderately sloping alpine glaciated lands, including moraines, cirque basins,

and trough bottoms. Parent materials are poorly weathered Seven Devils

volcanics and included limestone.

Accessory Characteristics: The primary soils are deep to very deep gravelly

loams, loams, and silt loams. The vegetation is coniferous forest. Mean

annual precipitation ranges from 76 to 114 centimeters (30 to 45 inches). The

elevation range is 1750 to 2500 meters (5700 to 8200 feet). The dominant

slopes have gradients of 10 to 50 percent. This unit is moderately dissected

by streams, with the dominant stream pattern being pinnate. Wetlands and lakes

are significant inclusions in basins and depressions.

LTA Components: This landtype association consists of moraines, cirque

basins, and trough bottoms.

Moraines are formed in mixed volcanic ash influenced loess and glacial till of

volcanic or limestone lithology. Slope gradients range from 5 to 50 percent.

Soils on these landforms are moderately deep to very deep, weakly developed

gravelly loams and silt loams with cobbly sandy loam substrata. These soils

are classified as Dystric Cryochrepts. Rock outcrop is less than 15 percent of

the unit. The dominant potential natural vegetation series at mid elevations

is grand fir and at high elevations subalpine fir. This component is 60

percent of the map unit.

Cirque basins are formed in volcanic ash influenced loess and glacial till of

volcanic or limestone lithology. Slope gradients range from 1 to 30 percent.

Soils on these landforms are moderately deep to very deep, weakly developed

gravelly loams and loams with very cobbly loam substrata. These soils are

classified as Dystric Cryochrepts. Rock outcrop is less than 10 percent of the

unit. The dominant potential natural vegetation series is subalpine fir. This

component is 20 percent of the map unit.

Trough bottoms are formed in mixed volcanic ash influenced loess, glacial till

and stratified outwash of volcanic or limestone lithology. Slope gradients

range from 1 to 30 percent. Soils in these landforms are very deep, weakly

developed gravelly loams and loams with very cobbly sandy loam or loam

substrata. These soils are classified as Dystric Cryochrepts and Entic

Cryumbrepts. The dominant potential natural vegetation series is subalpine

fir. This component is 20 percent of the map unit.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 334
LTA59-M332G

MOUNTAIN SLOPES AND RIDGES: GNEISSES, QUARTZITES AND SCHISTS

Location: This unit is located in mountains and canyons of north central

Idaho and central Idaho in the Salmon and Clearwater River basins.

 Acreage by Section

 59-M332G 6,706

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is colluvial mountain slopes.

Parent materials are moderately weathered gneiss, schist and quartzite

associated with the Idaho batholith.

Accessory Characteristics: The primary soils are deep to very deep silt

loams,

loams and sandy loams. The vegetation is dominantly coniferous forest, with

some grassland at low elevations on south aspects. Mean annual precipitation

ranges from 64 to 125 centimeters (25 to 50 inches). The elevation range is

700 to 2438 meters (2300 to 8000 feet). The dominant slopes have gradients of

35 to 50 percent. This unit is moderately dissected by streams, with the

dominant stream pattern being parallel. 

LTA Components: This landtype association consists of mountain slopes.

Mountain slopes are formed in volcanic ash influenced loess, residuum and

colluvium of felsic lithology. Soils on these landforms are deep to very

deep, moderately developed silt loams, loams and sandy loams with sandy or

substrata. Soils on low elevations on south aspects are Ultic Haploxerolls.

At mid elevations soils are classified as Andic Dystrochrepts and Typic

Dystrochrepts, and at high elevations they are Andic Cryochrepts and Dystric

Cryochrepts. Rock outcrop is less than 25 percent of the unit. The dominant

potential natural vegetation at low elevations is bluebunch wheatgrass, at mid

elevations, Douglas-fir and grand fir, and at high elevations, subalpine fir.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 335
LTA62-M332G

MOUNTAIN SLOPES AND RIDGES: WEAKLY WEATHERED GRANITICS

Location: This unit is located in the Seven Devils Mountains of west central

Idaho in the Snake River Basin.

 Acreage by Section

 62-M332G 2,305

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a nonglaciated steep

mountain slope landscape setting, below the zone of strong frost-churning, and

is typically composed of moderately dissected mountain slopes, ridge tops, and

minor amounts of narrow valley bottoms. Parent materials are colluvium and

residuum underlain by weakly weathered granitic bedrock.

Accessory Characteristics: The primary soils are moderately deep to deep loams

and sandy loams with very cobbly sandy loam, loamy sand or sand substrata. 

The vegetation is bunchgrass and coniferous forest. Mean annual precipitation

ranges from 64 to 114 centimeters (25 to 45 inches). The elevation range is

1200 to 2000 meters (4100 to 6700 feet). The dominant slopes have gradients of

20 to 55 percent. This unit is moderately dissected by streams, with the

dominant stream pattern being parallel. Wetlands are a minor component of

this unit.

LTA Components: This landtype association consists of mountain slopes and

ridge tops.

Soils are formed in colluvium and residuum. Slope gradients range from 35 to

55 percent. Soils on this landform are somewhat excessively drained or well

drained. The soils are weakly developed. The dominant soils are classified as

Ultic Haploxerolls, Typic Dystrochrepts, and Dystric Cryochrepts. Rock outcrop

occurs on about 10 percent of this component. The dominant potential natural

vegetation is Douglas-fir and Idaho fescue series, and at higher elevations,

grand fir and subalpine fir series.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 336
LTA64-M332G

MOUNTAIN SLOPES AND RIDGES: VOLCANICS

Location: This unit is located along streams and rivers, and adjacent to

basalt plateaus in west central Idaho.

 Acreage by Section

 64-M332G 133,556

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is colluvial mountain slopes

and usually is adjacent to steam breaks or plateaus. Parent materials are

poorly to moderately weathered Columbia River basalt, Seven Devils volcanics

and included limestone of the Martin Bridge formation.

Accessory Characteristics: The primary soils are moderately deep to deep loams

and cobbly loams. The vegetation is a mosaic of grassland and coniferous

forest. Mean annual precipitation ranges from 30 to 89 centimeters (12 to 35

inches). The elevation range is 240 to 2250 meters (800 to 7300 feet). The

dominant slopes have gradients of 35 to 50 percent. This unit is moderately

dissected by streams, with the dominant stream pattern being parallel. 

LTA Components: This landtype association consists of mountain slopes.

Mountain slopes are formed in mixed volcanic ash influenced loess, residuum

and colluvium of volcanic lithology. Slope gradients range from 35 to 50

percent. Soils on these landforms are moderately deep to deep, moderately

developed cobbly loams and loams with loamy or clayey substrata. These soils

are classified as Ultic Argixerolls and Dystric Cryochrepts. Rock outcrop is

less than 25 percent of the unit. The dominant potential natural vegetation

series at low elevations is bluebunch wheatgrass, at mid elevations

Douglas-fir and grand fir, and at high elevations subalpine fir/blue.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 337
LTA72-M332G

FROST SHATTERED MOUNTAIN RIDGE TOPS: WEAKLY WEATHERED GRANITICS

Location: This unit is located in the Seven Devils Mountain Range of west

central Idaho in the Snake and Salmon River Basins.

 Acreage by Section

 72-M332G 433

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs at high elevations in a

mountain ridge landscape setting which is typically composed of frost

shattered ridge tops and mountain slopes. Parent materials are colluvium and

residuum underlain by weakly weathered granitic rocks.

Accessory Characteristics: The primary soils are deep loams and sandy loams

with very cobbly loamy sand and sand substrata. The vegetation is coniferous

forest and montane parklands. Mean annual precipitation ranges from 76 to 102

centimeters (30 to 40 inches. The elevation range is from 1500 to 1800 meters

(5000 to 6000 feet). The dominant slopes have gradients of 15 to 50 percent.

This unit is slightly dissected by streams with the dominant stream pattern

being parallel, but grading to weakly dendritic. Wetlands are a minor

component of this unit. Small areas of glaciation are included in this map

unit.

LTA Components: This landtype association consists of frost shattered mountain

slopes and ridge tops.

Frost shattered convex ridges and slopes are formed in thin or mixed volcanic

ash influenced loess and residuum of granitic lithology. Soils on this

landform are deep and well drained, poorly developed gravelly loams or sandy

loams with very gravelly or cobbly loamy sand or sand substrata. These soils

are classified as Dystric Cryochrepts, Typic Dystrochrepts, and Entic

Cryumbrepts. Rock outcrop is less than 5 percent of this unit. The dominant

potential natural vegetation series at mid elevations is grand fir, and at

higher elevations subalpine fir and herbaceous openings. This component

represents 90 percent of this unit.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 338
LTA73-M332G

FROST SHATTERED MOUNTAIN RIDGE TOPS: VOLCANICS

Location: This unit is located in the Seven Devils Mountain Range of west

central Idaho in the Snake and Salmon River Basins

 Acreage by Section

 73-M332G 6,159

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs at high elevations in a

mountain ridge landscape setting which is typically composed of frost

shattered ridge tops and mountain slopes. Parent materials are colluvium and

residuum of andesite and rhyolite of the Seven Devils volcanics and included

limestone of the Martin Bridge formation.

Accessory Characteristics: The primary soils are deep loams and sandy loams

that have numerous angular rock fragments in the profile. The vegetation is

coniferous forest and montane parkland. Mean annual precipitation ranges from

76 to 140 centimeters (30 to 55 inches). The elevation range is 1500 to 2400

meters (5000 to 8000 feet). The dominant slopes have gradients of 15 to 50

percent. This unit is slightly dissected by streams, with the dominant stream

pattern being parallel, but grading to weakly dendritic. Wetlands are a minor

component of this unit. Small areas of glaciation are included.

LTA Components: This landtype association consists of frost shattered

mountain

slopes and ridge tops.

Frost shattered mountain slopes are formed in thin or mixed volcanic ash

influenced loess and residuum of volcanic and metasedimentary lithology.

Soils on this landform are deep and well drained, weakly developed gravelly

loams or silt loams with very gravelly or very cobbly loamy or sandy loam

substrata. The dominant soils are classified as Dystric Cryochrepts and Entic

Cryumbrepts. Rock outcrop occurs on less than 5 percent of this landscape

component. The dominant potential natural vegetation series at mid-elevations

is grand fir, and at higher elevations subalpine fir and herbaceous openings.

This component represents 90 percent of this unit.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 339
LTA82-M332G

LOW RELIEF HILLS: VOLCANICS

Location: This unit is located on plateaus and broad ridgetops above volcanic

canyonlands in west central Idaho, in the Snake and Salmon River Basins.

 Acreage by Section

 82-M332G 44,956

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is plateaus developed

primarily in loess and moderately weathered residuum of Columbia River basalt.

Accessory Characteristics: The primary soils are deep to very deep silt loams

and loams. The vegetation is dominantly grassland and minor coniferous forest.

Mean annual precipitation ranges from 30 to 127 centimeters (12 to 50 inches).

The elevation range is 240 to 1800 meters (800 to 5900 feet). The dominant

slopes have gradients of 5 to 30 percent. This unit is slightly to moderately

dissected by streams, with the dominant stream pattern being dendritic. 

LTA Components: This landtype association consists of plateaus.

Plateaus are formed in loess and residuum of volcanic lithology. Soils on

these landforms are deep to very deep, moderately developed silt loams with

clay or silty clay substrata. These soils are classified as Andeptic

Cryoboralfs. Rock outcrop is less than 10 percent of the unit. The dominant

potential natural vegetation series is bluebunch wheatgrass. At midelevations, Douglas-fir and grand fir are dominant. Western red cedar

occurs in the north part of the Clearwater River basin.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 340
LTA90-M332G

MASS WASTED SLOPES: MIXED GEOLOGY

Location: This unit is located in mountain slopes and canyonlands of west

central Idaho.

 Acreage by Section

 90-M332G 23,333

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is mass wasted slopes. They

are often adjacent to stream channels. Parent materials for this unit are

moderately to well weathered parent materials of any lithology, but in this

Section are dominantly volcanics.

Accessory Characteristics: The primary soils are deep to very deep loams and

cobbly loams. The vegetation is a mosaic of grassland and coniferous forest.

Mean annual precipitation ranges from 30 to 102 centimeters (12 to 40 inches).

The elevation range is 275 to 1500 meters (900 to 5000 feet). The dominant

slopes have gradients of 30 to 80 percent. This unit is poorly to moderately

dissected by streams, and while the dominant pattern is parallel, the stream

pattern may be deranged by slope movement. Wetlands are sometimes a minor

component.

LTA Components: This landtype association consists of mass wasted slopes,

including benches and scarps.

Mass wasted slopes are formed in mixed volcanic ash influenced loess, residuum

and colluvium of dominantly volcanic lithology. Soils on these landforms are

deep to very deep, moderately developed cobbly loams and loams with loamy or

clayey substrata. These soils are classified as Ultic Argixerolls and Typic

Dystrochrepts. Landslide scarps may have shallower soils. Rock outcrop is less

than 10 percent of the unit. The dominant potential natural vegetation series

at low elevations is bluebunch wheatgrass, and at mid elevations, Douglas-fir

and grand fir.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 341
CHAPTER 11 

LTA Descriptions 

Section M333A-Okanogan Highlands

This Section occurs in northeast Washington and northern Idaho and is

dominated by Continentally Glaciated Mountains. Nineteen LTAs were mapped in

this Section. See Appendix F for a complete list of LTAs and their acreages. 

Map unit descriptions are preceded by the following illustrations:

 Figure 45: Map showing location of M333A within the Northern Region

 Figure 46: M333A landscape photograph

 Selkirk Mountains, Idaho Panhandle National Forests

 Figure 47: Map showing distribution of LTAS within M333A

 Figure 48: Bar chart showing abundance of landform groups within M333A

 Figure 49: Bar chart showing abundance of geologic material groups within 

 M333A

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 342
LTA10-M333A

 VALLEYS: RECENT COARSE ALLUVIUM

Location: These units occur in the Selkirk Mountains of the Priest, Pend

Oreille, Kootenai and Spokane River basins of northwestern Idaho and northeast

Washington.

 Acreage by Section

 10-M333A 38,951

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a valley bottom

landscape setting at elevations that range from low to high. The unit is

typically composed of wide glacial trough bottoms. Parent materials are

surface volcanic ash overlying mostly outwash with a narrow deposit of recent

alluvium near the stream. These materials are usually derived fromgranitic

bedrock sources.

Accessory Characteristics: The primary soils are generally deep stratified

sands. The vegetation is a mosaic of mixed coniferous and alpine forest with

associated riparian plants. Mean annual precipitation ranges from 76 to 152

centimeters (30 to 60 inches). The elevation range of this unit is 610 to 1829

meters (2000 to 6000 feet). The dominant slopes have gradients of 2 to 15

percent.

LTA Components: This landtype association consists of toeslopes and stream

terraces, floodplains, and alluvial basins.

Toeslopes and stream terraces are formed in coarse alluvium, some stratified.

These toeslopes and terraces have slope gradients that range from 2 to 20

percent. Soils on these landforms are deep, poorly developed and consist

mostly of sand and gravel. The major soils are classified as Andic

Dystrochrepts and Andic Cryochrepts, along with Typic Udivitrands and Vitric

Haplocryands. The dominant potential natural vegetation series on the well

drained, high elevation sites are subalpine fir with western hemlock and

western redcedar occurring at low to mid-elevations. This component represents

about 60 percent of the map unit.

Floodplains and alluvial basins are formed in coarse, stratified and

unstratified alluvium. These areas have slope gradients that range from 0 to

10 percent. Soils on these landforms are deep, poorly developed and consist

mostly of sand and gravel. The major soils are classified as Humic

Udivitrands, Vitric Fulvicryands, Pachic Haplumbrepts and Typic Haplaquepts.

The dominant potential natural vegetation series are subalpine fir in the

higher elevations and cold air drainage areas, with western redcedar in the

low and mid-elevations.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 343
LTA11-M333A

VALLEYS: LACUSTRINE SEDIMENTS

Location: These units occur in the Selkirk Mountains of the Priest, Pend

Oreille, Kootenai and Spokane River basins of northwestern Idaho and northeast

Washington.

 Acreage by Section

 11-M333A 220,526

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a valley bottom

landscape setting at low elevations. The unit is typically composed of glacial

Lacustrine plains, benches and draws. Parent materials are surface volcanic

ash overlying silty lake sediments.

Accessory Characteristics: The primary soils are deep, silty, lacustrine

sediments from unnamed glacial lakes. The vegetation is a mosaic of mixed

coniferous forest. Mean annual precipitation ranges from 64 to 76 centimeters

(25 to 30 inches). The elevation range of this unit is 536 to 762 meters (1760

to 2500 feet). The dominant slopes have gradients of 0 to 55 percent.

LTA Components: This landtype association consists of flat plains, benches

and draws.

Flat plains, benches and draws are formed in mostly deep fine- silty or

coarse-silty lacustrine sediments. Some sandy and loamy sediments also occur.

Slope gradients range from 0 to 60 percent. Soils on these landforms are deep,

poorly developed and consist mostly of silt with some sands and loams. The

deposits found around Bonners Ferry are calcareous. The major soils are

classified as Typic Udivitrands. Other soils which occur are Andic

Eutrochrepts and Andic Fragixeralfs. The dominant potential natural vegetation

series are western redcedar, grand fir, and Douglas-fir.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 344
LTA12-M333A

VALLEYS: OUTWASH AND OTHER OLDER COARSE ALLUVIAL DEPOSITS

Location: These units occur in the Selkirk Mountains of the Priest, Pend

Oreille, and Spokane River basins of northwestern Idaho and northeast

Washington.

 Acreage by Section

 12-M333A 323,513

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a valley bottom

landscape setting at elevations that range from low to high. The unit is

typically composed outwash plains, alluvial fans and glacial terraces. Parent

materials are surface volcanic ash overlying mostly outwash with a narrow

deposit of recent alluvium near the stream. These materials are derived from

belt and granitic bedrock sources.

Accessory Characteristics: The primary soils are deep, intermixed and

stratified gravels, sands, and silts. The vegetation is a mosaic of mixed

coniferous and alpine forest with associated riparian plants. Mean annual

precipitation ranges from 76 to 152 centimeters (30 to 60 inches). The

elevation range of this unit is 536 to 1646 meters (1760 to 5400 feet). The

dominant slopes have gradients of 0 to 20 percent, but some steep terrace

escarpments have gradients up to 75 percent.

LTA Components: This landtype association consists of outwash plains,

terraces and rolling surfaces.

Outwash plains and terraces and rolling surfaces are formed in coarse outwash

and alluvium, some stratified. These plains and terraces have slope gradients

that generally range from 2 to 20 percent. Soils on these landforms are deep,

poorly developed and consist mostly of sand and gravel. The major soils on the

well drained sites are classified as Andic Dystrochrepts and Andic

Cryochrepts, along with Typic Udivitrands and Vitric Haplocryands. The major

soils on the poorly drained sites are classified as Humic Udivitrands, Vitric

Fulvicryands, Pachic Haplumbrepts and Typic Haplaquepts. The dominant

potential natural vegetation series on the well drained, high elevation sites

are subalpine fir, with western hemlock, western redcedar, grand fir and

Douglas-fir occurring at low to mid elevations. The dominant potential natural

vegetation on the poorly drained sites is subalpine fir in the higher

elevations and cold air drainage areas, with western redcedar in the low and

mid elevations. 

Compiled by: Jerry Niehoff, Idaho Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 345
LTA14-M333A

VALLEYS: RECENT FINE ALLUVIUM 

Location: These units occur in the lower part of the Purcell Trench and the

Pend Oreille River basin of northwestern Idaho.

 Acreage by Section

 14-M333A 14,384

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a valley bottom

landscape setting at low elevations. The unit is typically composed low stream

terraces, flood plains and bottom lands. Parent materials are surface volcanic

ash overlying fine recent alluvium near streams. These materials are derived

from belt and granitic bedrock sources.

Accessory Characteristics: The primary soils are deep, poorly drained, silt

loams and very fine sandy loams. The vegetation is a mosaic of grass meadows with

associated riparian plants. Mean annual precipitation ranges from 64 to 76

centimeters (25 to 30 inches). The elevation range is 640 to 914 meters (2100

to 3000 feet). The dominant slopes have gradients of 0 to 4 percent.

LTA Components: This landtype association consists of floodplains and bottom

lands.

Floodplains and bottom lands are formed in fine alluvium. These landscapes

have slope gradients that generally range from 0 to 10 percent. Soils on these

landforms are very deep and consist mostly of silt loams and very fine sands.

The major soils are classified as Mollic Andaquepts, medial, nonacid, frigid;

Typic Borosaprists, and Typic Haplaquolls, fine, mixed, frigid. The dominant

vegetation consists of grasses, forbs and shrubs.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 346
LTA20-M333A

BREAKS: METASEDIMENTARY (BELT)

Location: These units occur in the St. Joe, Coeur d' Alene and Clearwater

Mountains of the Bitterroot range, which are part of the Clark Fork, Coeur d'

Alene, St. Joe and Clearwater River basins of northwest Montana and northern

Idaho.

 Acreage by Section

 20-M333A 17,556

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs primarily at low to mid

elevations, on steep slopes adjacent to stream drainages. Parent materials are

surface volcanic ash overlying weakly to moderately weathered quartzites,

siltites and argillites from Precambrian metasedimentary bedrock. In Montana

surface ash may or may not occur.

Accessory Characteristics: The primary soils are shallow to deep loams and

sandy loams, with a small to moderate component of rock outcrop and scree. 

The vegetation is a mosaic of coniferous forest. Mean annual precipitation

ranges from 36 to 152 centimeters (14 to 60 inches). The elevation range is

655 to 1524 meters (2150 to 5000 feet). The dominant slopes have gradients

that are greater than 60 percent. This unit is non-dissected to moderately

dissected by streams, with the dominant stream pattern being parallel. 

LTA Components: This landtype association consists of dissected and

non-dissected stream breaks. Structural breaks are also included.

Stream breaks are the steep, mountain slopes adjacent to stream drainages,

some of these steep slopes are dissected and other are not. The slope

gradients range from 50 to greater than 100 percent. Soils on these landforms

are shallow to deep, weakly to moderately weathered and medium textured. The

major soils on the well drained sites are classified as Typic Udivitrands and

Alfic Udivitrands with xeric phases of these on some southerly aspects. Humic

Udivitrands occur in the more poorly drained sites. Rock outcrop and scree

occupy less than 10 percent to over 50 percent of the area. In western Montana

the major soils are classified as Lithic Dystrochrepts, Typic Dystrochrepts,

and Andic Dystrochrepts. The dominant potential natural vegetation on the well

drained, moist sites are western redcedar, western hemlock and grand fir

series; on drier sites grand fir and Douglas-fir. The dominant potential

natural vegetation series on poorly drained sites is western redcedar.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 347
LTA22-M333A

 BREAKS: WEAKLY WEATHERED GRANITICS 

Location: These units occur in the Selkirk Mountains of the Kootenai River

basin of northern Idaho.

 Acreage by Section

 22-M333A 4,297

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs primarily at low to mid

elevations, on steep slopes adjacent to stream drainages and along the Purcell

trench. Parent materials are surface volcanic ash overlying glacial till, or

lacustrine sediments, with an underlying bedrock consisting of granite,

granodiorite or similar rocks of the Kaniksu Batholith bedrock.

Accessory Characteristics: The primary soils are shallow to deep sands and

sandy loams, with a small to moderate component of rock bedrock and scree. The

vegetation is a mosaic of coniferous forest. Mean annual precipitation

ranges from 64 to 102 centimeters (25 to 40 inches). The elevation range is

670 to 1341 meters (2200 to 4400 feet). The dominant slopes have gradients

that are greater than 60 percent.

LTA Components: This landtype association consists of stream breaks with some

structural breaks included.

Stream breaks are the steep, mountain slopes adjacent to stream drainages,

some of these steep slopes are dissected and others are not. The slope

gradients range from 50 to 100+ percent. Soils on these landforms are shallow

to deep, weakly weathered and coarse textured. The major soils on the well

drained sites are classified as Andic Dystrochrepts and Andic Xerochrepts on

the drier sites. On open dry aspects the volcanic ash is thinner and the

dominant soils here are Typic Xerochrepts. Rock outcrop and scree occupy less

than 10 percent to over 50 percent of this area. The dominant potential

natural vegetation on the more moist sites is western redcedar and western

hemlock, with Douglas-fir on the dryer sites.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 348
LTA28-M333A

 LTA28-M333D

 DISSECTED BREAKS: METASEDIMENTARY (BELT)

Location: These units occur in the Coeur d' Alene Mountains of the

Bitterroot range, which are part of the Coeur d' Alene River basin of northern

Idaho.

 Acreage by Section

 28-M333A 426

 28-M333D 316,745

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a low to mid

elevation, moderately steep to steep sloping, mountain sideslope and stream

breaks landscape setting, which is typically composed of dissected lower

mountain slopes and stream breaks comprised of colluvium and residuum. Parent

materials are surface volcanic ash overlying weakly to moderately weathered

quartzites, siltites and argillites from Precambrian metasedimentary bedrock.

Accessory Characteristics: The primary soils are shallow to deep loams and

sandy loams, with a component of rock outcrop and scree. The vegetation is a

mosaic of coniferous forest. Mean annual precipitation ranges from 64 to

140 centimeters (25 to 55 inches). The elevation range of this unit is 655 to

1524 meters (2150 to 5000 feet). The dominant slopes have gradients of 45 to

80 percent. This unit is moderately to highly dissected by streams, with the

dominant stream pattern being parallel. The landscapes of this area are all

generally under 5000 feet and in a high rain-on-snow frequency area.

LTA Components: This landtype association consists of lower mountain slopes

and breaks which have alternating dissected draws and spur ridges.

Dissected draws occur on moderately steep to steep slopes, and are formed in

metasediments that consist of quartzites, siltites and argillites. The slope

gradients range from 45 to 80 percent. Soils on these landforms are shallow to

deep, weakly to moderately weathered and medium textured. The major soils on

the well drained sites within the draw are classified as Typic Udivitrands and

Alfic Udivitrands. Xeric phases of these occur on some of the southerly

aspects. Humic Udivitrands occur in the more poorly drained sites. Rock

outcrop or scree occupies 10 to 30 percent of this unit. The dominant

potential natural vegetation on the well drained sites are western redcedar,

western hemlock and grand fir. The dominant potential natural vegetation on

the poorly drained sites is western redcedar. This component represents about

50 percent of this unit

Non-dissected spur ridges occur on moderately steep to steep slopes and are

formed in the same Belt metasediment rock types stated in the landscape

component above. The slope gradients range from 45 to 80 percent. Soils on

these landforms are shallow to deep, weakly to moderately weathered and 

medium textured. The major soils are classified as Typic Udivitrands, with

xeric phases on dryer, southerly aspects. Moderately weathered soils consist

of Alfic Udivitrands and Alfic Vitrixerands. Rock outcrop and scree occupies

10 to 30 percent of this unit. The dominant potential natural vegetation is

western redcedar, western hemlock, grand fir and Douglas-fir. This component

represents about 50 percent of this unit.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 349
LTA40-M333A

STEEP GLACIATED MOUNTAIN SLOPES: METASEDIMENTARY (BELT)

Location: These units occur in the Selkirk Mountains of the Priest, Pend

Oreille, Kootenai and Spokane River basins of northwestern Idaho and northeast

Washington.

 Acreage by Section

 40-M333A 6,270

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a steep, continental

glaciated landscape setting, which is typically composed of steep glacial

trough walls and headwalls. Substratum materials are glacial tills and

residuum derived from mainly Precambrian metasediments composed of quartzites,

siltites and argillites. Where these rocks have come in contact with

intrusions of sills or the Kaniksu batholith they have been altered to

schists, amphibolites, phyllites and other metamorphic rocks. The Shedroof

conglomerate and Leola volcanics formations occur on the northern boundary of

Idaho and Washington.

Accessory Characteristics: The primary soils are shallow to deep sandy loams,

with inclusions of rock outcrop, scree and avalanche chutes. The vegetation is

a mosaic of coniferous forest. Mean annual precipitation ranges from 76 to 178

centimeters (30 to 70 inches). The elevation range is 914 to 2344 meters (3000

to 7690 feet). The dominant slopes have gradients greater than 60 percent.

This unit is moderately to highly dissected by streams, with the dominant

stream pattern being parallel. 

LTA Components: This landtype association consists of steep, dissected, mid

to high elevation, continentally glaciated troughwalls and headwalls.

These steep, glaciated troughwalls and headwalls consist of glacial till or

residuum derived from metasedimentary bedrock and other local bedrock sources.

The slope gradients range from 50 to 110 percent. Soils on these landforms are

shallow to deep, weakly weathered and medium textured. The major soils on the

high elevation, well drained sites are classified as Andic Cryochrepts, Vitric

Haplocryands, and Lithic Cryochrepts. Andic Cryumbrepts and Vitric

Fulvicryands occur in the more poorly drained sites. The major soils at mid

elevations, well drained sites are classified as Andic Dystrochrepts, Typic

Udivitrands, and Lithic Dystrochrepts. Andic Haplumbrepts and Humic

Udivitrands occur in the more poorly drained sites. Rock outcrop, scree and

avalanche chutes commonly occur in this unit. The dominant potential natural

vegetation on the high elevation, well drained sites are subalpine fir along

with grassy balds. Western hemlock, western redcedar, grand fir and

Douglas-fir occur at lower elevations. The dominant potential natural

vegetation on the poorly drained sites are subalpine fir at the higher

elevations and western redcedar at mid and lower elevations.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 350
LTA41-M333A

 STEEP GLACIATED MOUNTAIN SLOPES: GRANITICS

Location: These units occur primarily in the Selkirk Mountains of the Priest,

Pend Oreille, Kootenai and Spokane River basins of northwestern Idaho and

northeast Washington.

 Acreage by Section

 41-M333A 22,952

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a steep, continental

and alpine glaciated landscape setting, which is typically composed of steep

glacial trough walls cirque headwalls and associated basins. Substratum

materials are glacial tills and residuum derived from mainly Cretaceous or

Tertiary aged Kaniksu batholith composed of granite, granodiorite or other

rocks of similar composition. 

Accessory Characteristics: The primary soils are shallow to deep sands and

sandy loams, with a significant component of rock outcrop, scree and avalanche

chutes. The vegetation is a mosaic of coniferous forest. Mean annual

precipitation ranges from 76 to 178 centimeters (30 to 70 inches). The

elevation range is 975 to 2250 meters (3200 to 7380 feet). The dominant slopes

have gradients greater than 60 percent. This unit is moderately to highly

dissected by streams, with the dominant stream pattern being parallel.

Wetlands and lakes are a major component of the cirque basin and narrow valley

bottom of this unit. 

LTA Components: This landtype association consists of steep, dissected, mid

to high elevation, continentally and alpine glaciated troughwalls, headwalls

and associated basins and narrow bottoms.

The steep, glaciated troughwalls and headwalls consist of glacial till or

residuum derived from batholith that consists of granite, granodiorite or

other local bedrock sources. The slope gradients range from 50 to 110 percent.

Soils on these landforms are shallow to deep, weakly weathered and coarse to

medium textured. The major soils on the high elevation, well drained sites are

classified as Andic Cryochrepts, Vitric Haplocryands, and Lithic Cryochrepts.

Andic Cryumbrepts and Vitric Fulvicryands occur in the more poorly drained

sites. The major soils at mid elevations, well drained sites are classified

as Andic Dystrochrepts, Typic Udivitrands, and Lithic Dystrochrepts. Andic

Haplumbrepts and Humic Udivitrands occur in the more poorly drained sites.

Rock outcrop, scree and avalanche chutes commonly occur in this unit. The

dominant potential natural vegetation on the high elevation, well drained

sites is subalpine fir series along with grassy balds. Western hemlock,

western redcedar, grand fir and Douglas-fir occur at lower elevations. The

dominant potential natural vegetation on the poorly drained sites are

subalpine fir at the higher elevations and western redcedar at mid and lower

elevations. This component represents about 80 percent of this unit.

The cirque basins and narrow valley bottoms occur on gentle slopes and are

formed in batholith that consists of granite, granodiorite or other rocks of

similar composition. The slope gradients range from 0 to 35 percent. Soils on

these landforms are mostly deep, weakly weathered and coarse to medium

textured. The major well drained soils in the cirque basins and narrow valley

bottoms are Andic Cryochrepts and Vitric Haplocryands. On poorly drained sites

the major soils are Andic Cryumbrepts and Vitric Fulvicryands. The dominant

potential natural vegetation is subalpine fir series. This component

represents about 20 percent of the unit. 

Compiled by: Jerry Niehoff, Idaho Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 351
LTA46-M333A

ALPINE TROUGHS AND TROUGHWALLS: GRANITICS 

Location: These units occur in the Selkirk Mountains of north Idaho.

 Acreage by Section

 46-M333A 30,843

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs at higher elevations,

in a gentle to steep, alpine glacial landscape setting, which is typically

composed of alpine trough bottoms and troughwalls. Parent materials are Mazama

volcanic ash overlying weakly weathered granitic tills and bedrock of the

Kaniksu Batholith.

Accessory Characteristics: The primary soils are shallow to moderately deep

with textures ranging from silt loam to loam surface textures, and

non-gravelly to very gravelly or cobbly sand, loamy sand and sandy loam

subsurface layers. The vegetation is a mosaic of coniferous forest and rock

outcrops. Mean annual precipitation ranges from 125 to 175 cms (50 to 70

inches). The elevation range is 1524 to 2347 meters (5000 to 7700 feet). The

dominant slopes range from 1 percent in the trough bottoms to more than 60

percent on the troughwalls. This unit is moderate to highly dissected by

streams, with the dominant stream pattern being parallel. Wetlands and moist

seeps are a major component of this unit.

LTA Components: This landtype association consists of glacial troughwalls and

glacial trough bottoms.

The glacial troughwalls are formed in granitics of the Kaniksu Batholith with

a mixed surface layer of Mazama volcanic ash of varying thickness. Slope

gradients range from 40 to more than 60 percent. Soils on these landforms are

shallow to moderately deep, weakly to moderately developed, and consist mostly

of silt loam and loam surface textures, and non-gravelly to very gravelly or

cobbly sands, loamy sands, and sandy loam subsurface textures. These soils are

classified as Andic Cryochrepts, Vitric Haplocryands, Andic Cryumbrepts and

Lithic Cryochrepts. Some Spodosols occur at higher elevations. The soils

sometimes have dense till substratums. Rock outcrop occurs on 10 to 30 percent

of this landscape component. The dominant potential natural vegetation is

subalpine fir. This component represents about 70 percent of this unit.

The trough bottoms consist of Mazama ash overlying glacial till, glacio-fluvial

sediments and alluvium. Slope gradients range from 1 to 30 percent. Soils on

these landforms are generally deep, and consist mostly of silt loam and loam

volcanic ash surface textures over a wide assortment of textures derived from

till, alluvium and glacio-fluvial sediments. Many wet soils occur in these

bottoms. The soils are classified as Ochrepts, Aquepts, Umbrepts and Cryands.

Rock outcrop is uncommon. The dominant potential natural vegetation is

subalpine fir. This component represents about 30 percent of this unit.

Compiled by: Gary Ford, Regional Office

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 352
LTA50-M333A

GLACIATED MOUNTAIN SLOPES: METASEDIMENTARY (BELT) 

Location: These units occur in the Selkirk Mountains of the Priest, Pend

Oreille and Spokane River basins of northwestern Idaho and northeast

Washington.

 Acreage by Section

 50-M333A 180,003

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a gentle to

moderately steep valley bottom, mountain sideslope and ridge landscape setting

at elevations that range from low to high. The unit is typically composed of

dissected and non dissected mountain slopes, valleys and ridges comprised of

alpine and continental till. Parent materials are surface volcanic ash

overlying substratum materials of glacial tills derived from mainly

Precambrian metasediments composed of quartzites, siltites and argillites. 

Where these rocks have come in contact with intrusions of sills or the Kaniksu

batholith they have been altered to schists, amphiboles, phyllites and other

metamorphic rocks. The Shedroof conglomerate and Leola volcanics formations

occur on the, northern boundary of Idaho and Washington.

Accessory Characteristics: The primary soils are shallow to deep sandy loams,

with a small component of rock outcrop and scree. The vegetation is a mosaic

of coniferous forest. Mean annual precipitation ranges from 76 to 178

centimeters (30 to 70 inches). The elevation range of this unit is 800 to 2062

meters (2625 to 6765 feet). The dominant slopes have gradients of 15 to 55

percent. This unit is slightly to highly dissected by streams, with the

dominant stream pattern being parallel. 

LTA Components: This landtype association consists of dissected and

non-dissected, continentally glaciated, convex ridges and concave valleys.

The glaciated convex ridges and mountain sideslopes were strongly scoured and

then covered by varying thickness of glacial tills. The slope gradients range

from near level to 60 percent. The drainage bottoms and toeslopes consist of

deep glacial tills and glacio-fluvial materials. The slope gradients range

from 0 to 40 percent. Soils on the ridge and mountain sideslopes landforms are

shallow to deep, weakly weathered, and medium textured. Soils in the drainage

bottoms and toeslopes are deep, weakly weathered, and medium textured. The

major soils on the well drained sites are classified as Andic Cryochrepts and

Andic Dystrochrepts, with Andic Xerochrepts on the dryer sites. The areas with

deeper ash caps are Vitric Haplocryands and Typic Udivitrands. Andic

Cryumbrepts-Andic Haplumbrepts occur in the more poorly drained sites. Rock

outcrop and scree occurs as an inclusion in the scoured ridge and mountain

sideslope landforms. The dominant potential natural vegetation on the well

drained, high elevation sites is subalpine fir with western hemlock, western

redcedar, grand fir and Douglas-fir occurring at low to mid elevations. The

dominant potential natural vegetation on the poorly drained sites are

subalpine fir at the higher elevations and cold air pockets at lower

elevations, and western redcedar at the mid and lower elevations.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 353
LTA51-M333A

LTA51-M333D

GLACIATED MOUNTAIN SLOPES: GRANITICS

Location: These units occur primarily in the Selkirk Mountains of the Priest,

Pend Oreille and Spokane River basins of northwestern Idaho and northeast

Washington.

 Acreage by Section

 51-M333A 467,331

 51-M333D 3,788

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a gentle to

moderately steep valley bottom, mountain sideslope and ridge landscape setting

at elevations that range from low to high. The unit is typically composed of

dissected and non-dissected mountain slopes, valleys and ridges comprised of

alpine and continental till. Parent materials are surface volcanicash

overlying substratum materials of glacial tills derived from Cretaceous

Kaniksu Batholith bedrock.

Accessory Characteristics: The primary soils are shallow to deep sands, with

a small component of rock outcrop and scree. The vegetation is a mosaic of

coniferous forest. Mean annual precipitation ranges from 76 to 178 centimeters

(30 to 70 inches). The elevation range is 800 to 2062 meters (2625 to 6765

feet). The dominant slopes have gradients of 15 to 55 percent. This unit is

slightly to highly dissected by streams, with the dominant stream pattern

being parallel. 

LTA Components: This landtype association consists of dissected and

non-dissected, continentally glaciated, convex ridges and concave valleys.

The glaciated convex ridges and mountain sideslopes were strongly scoured and

then covered by varying thickness of glacial tills. The slope gradients range

from near level to 60 percent. The drainage bottoms and toeslopes consist of

deep glacial tills and glacio-fluvial materials. The slope gradients range

from 0 to 40 percent. Soils on the ridge and mountain sideslopes landforms are

shallow to deep, weakly weathered, and sandy textured. Soils in the drainage

bottoms and toeslopes are deep, weakly weathered, and sandy textured. The

major soils on the well drained sites are classified as Andic Cryochrepts and

Andic Dystrochrepts, with Andic Xerochrepts on the drier sites. The areas with

deeper ash caps are Vitric Haplocryands and Typic Udivitrands, Andic

Cryumbrepts-Andic Haplumbrepts occur in the more poorly drained sites. Rock

outcrop and scree occurs as an inclusion in the scoured ridge and mountain

sideslope landforms. The dominant potential natural vegetation on the well

drained, high elevation sites is subalpine fir with western hemlock, western

redcedar, grand fir and Douglas-fir occurring at low to mid elevations. The

dominant potential natural vegetation on the poorly drained sites issubalpine

fir at the higher elevations and cold air pockets at lower elevations, and

western redcedar at the mid and lower elevations.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 354
LTA60-M333A

MOUNTAIN SLOPES AND RIDGES: METASEDIMENTARY (BELT)

Location: These units occur in the Selkirk Mountains of the Priest, Pend

Oreille and Spokane River basins of northwestern Idaho and northeast

Washington.

 Acreage by Section

 60-M333A 124,084

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a low to mid

elevation, gentle to steep sloping, mountain sideslope and ridge landscape

setting, which is typically composed of dissected and non-dissected mountain

slopes, nivational hollows and ridges comprised of colluvium and residuum.

Parent materials are surface volcanic ash overlying weakly to moderately

weathered quartzites, siltites and argillites from Precambrian metasedimentary

bedrock.

Accessory Characteristics: The primary soils are shallow to deep loams and

sandy loams, with a small component of rock outcrop and scree. The vegetation

is a mosaic of coniferous forest. Mean annual precipitation ranges from 64

to 152 centimeters (25 to 60 inches). The elevation range is 655 to 1524

meters (2150 to 5000 feet). The dominant slopes have gradients of 20 to 70

percent. This unit is slightly to moderately dissected by streams, with the

dominant stream pattern being parallel to dendritic. 

LTA Components: This landtype association consists of dissected and

non-dissected mountain slopes, nivational hollows and ridges.

Dissected mountain slopes and nivational hollows occur on moderately steep to

steep slopes and are formed in metasediments that consist of quartzites,

siltites and argillites. The slope gradients range from 35 to 70 percent.

Soils on these landforms are shallow to deep, weakly to moderately weathered

and medium textured. The major soils on the well drained sites are classified

as Typic Udivitrands and Alfic Udivitrands with xeric phases of these occur on

some of the southerly aspects; and Andic Dystrochrepts. Humic Udivitrands

occur in the more poorly drained sites. Rock outcrop and scree occupies less

than 5 percent of this unit. The dominant potential natural vegetation on the

well drained sites are western redcedar, western hemlock, and grand fir. The

dominant potential natural vegetation on the poorly drained sites is western

redcedar. This component represents about 40 percent of this unit.

Non-dissected mountain slopes and ridges occur on gentle to moderately steep

slopes, and are formed in the same Belt Metasedimentary rock types stated in

the landscape component above. The slope gradients range from 10 to 60

percent. Soils on these landforms are shallow to deep and are medium

textured. The major soils are classified as Typic Udivitrands; xeric phase on

dryer, southerly aspects; Andic Dystrochrepts and Andic Xerochrepts.

Moderately weathered soils consist of Alfic Udivitrands and Alfic

Vitrixerands. Rock outcrop and scree occupies less than 5 up to 10 percent of

the area. The dominant potential natural vegetation is western redcedar,

western hemlock, grand fir and Douglas-fir. This component represents about 60

percent of this unit.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 355
LTA61-M333A

MOUNTAIN SLOPES AND RIDGES: HIGHLY WEATHERED GRANITICS

Location: These units occur in the Selkirk Mountains of the Priest, Pend

Oreille and Spokane River basins of northwestern Idaho and northeast

Washington.

 Acreage by Section

 61-M333A 16,288

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a low to mid

elevation, gentle to moderately sloping, mountain sideslope and ridge

landscape setting, which is typically composed of dissected mountain slopes

and ridges comprised of colluvium and residuum. Parent materials are surface

volcanic ash overlying highly weathered granitics from Cretaceous Kaniksu

Batholith.

Accessory Characteristics: The primary soils are moderately deep to deep

sands, sandy loams and loams. The vegetation is a mosaic of coniferous

forest. Mean annual precipitation ranges from 64 to 127 centimeters (25 to 50

inches). The elevation range is 655 to 1524 meters (2150 to 5000 feet). The

dominant slopes have gradients of 20 to 55 percent. This unit is moderately to

highly dissected, many of the draws do not have discernable active streams in

the bottom. The dominant stream pattern tends to be dendritic.

LTA Components: This landtype association consists of dissected mountain

slopes and ridges.

Dissected mountain slopes and ridges occur on gentle to moderately steep

slopes and are formed in batholith that consists of granite, granodiorite or

other rocks of similar composition. The slope gradients range from 10 to 60

percent. Soils on these landforms are moderately deep to deep, highly

weathered and coarse to medium textured. The major soils on both the well

drained sites and the more poorly drained sites are classified as Typic

Udivitrands, Typic Udivitrands, Alfic Udivitrands; xeric phases of these occur

on some of the southerly aspects. The dominant potential natural vegetation on

the well drained sites are western redcedar, western hemlock, and grand fir.

The dominant potential natural vegetation on the poorly drained sites are

western redcedar.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 356
LTA62-M333A

MOUNTAIN SLOPES AND RIDGES: WEAKLY WEATHERED GRANITICS

Location: These units occur in the Selkirk Mountains of the Priest, Pend

Oreille and Spokane River basins of northwestern Idaho and northeast

Washington.

 Acreage by Section

 62-M333A 162,063

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a low to mid

elevation, gentle to moderately sloping, mountain sideslope and ridge

landscape setting, which is typically composed of weakly dissected and non

dissected mountain slopes, and ridges comprised of colluvium and residuum. 

Parent materials are surface volcanic ash overlying weakly to moderately

weathered granitics from Cretaceous Kaniksu Batholith bedrock.

Accessory Characteristics: The primary soils are moderately deep to deep

sands and sandy loams. The vegetation is a mosaic of coniferous forest. Mean

annual precipitation ranges from 64 to 127 centimeters (25 to 50 inches). The

elevation range is 655 to 1524 meters (2150 to 5000 feet). The dominant slopes

have gradients of 20 to 55 percent. This unit is weakly to non dissected by

streams, with the dominant stream pattern being parallel when they occur.

LTA Components: This landtype association consists of weakly to non-dissected

mountain slopes and ridges.

Weakly to non-dissected mountain slopes and ridges occur on gentle to

moderately steep slopes and are formed in batholith that consists of granite,

granodiorite or other rocks of similar composition. The slope gradients range

from 10 to 60 percent. Soils on these landforms are moderately deep to deep,

weakly to moderately weathered and coarse to medium textured. The major soils

are classified as Typic Udivitrands. The moderately weathered soils consist of

Alfic Udivitrands. Xeric phases of these occur on some of the southerly

aspects. The dominant potential natural vegetation is western redcedar,

western hemlock, grand fir and Douglas-fir.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 357
LTA64-M333A

MOUNTAIN SLOPES AND RIDGES: VOLCANICS

Location: These units compose a basaltic plateau, located north and west of

Hayden Lake and adjacent to the eastern edge of the Rathdrum Prairie.

 Acreage by Section

 64-M333A 6,316

LTA Setting and General Characteristics

Differentiating characteristics: This map unit consists of a plateau, and

escarpments at low elevations. Parent materials are surface volcanic ash

overlying poorly to moderately weathered Columbia River basalt.

Accessory Characteristics: The primary soils are moderately deep, stony loams

and stony silt loams. The vegetation is a mosaic of coniferous forest. Mean

annual precipitation ranges from 64 to 79 centimeters (25 to 30 inches). The

elevation range of this unit is 701 to 914 meters (2300 to 3000 feet). The

dominant slopes have gradients of 15 to 55 percent. This unit is moderately

dissected by streams with the dominant stream pattern being parallel. 

LTA Components: This landtype association consists of a plateau and

associated escarpments.

The plateau and escarpments are formed in mixed volcanic ash influenced loess

overlying residuum and colluvium of basalt. Slope gradients range from 15 to

50 percent and the steeper escarpment walls range from 50 to 65+ percent.

Soils on these landforms are generally moderately deep, weakly to moderately

weathered, and medium textured. These soils are classified as Typic

Udivitrands and Typic Xerochrepts. The dominant potential natural vegetation

is grand fir and Douglas-fir on the well drained sites. Grand fir will occur

in the draws and on some north aspects with deeper soils.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 358
LTA66-M333A

LTA66-M333D

MOUNTAIN SLOPES AND RIDGES: CARBONATES

Location: This LTA is located adjacent to Lake Pend Oreille in the Coeur

d'Alene Mountains on the Idaho Panhandle National Forests.

 Acreage by Section

 66-M333A 512

 66-M333D 594

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of stream dissected mountain slopes.

Parent materials are Mazama volcanic ash over weakly weathered limestone

bedrock associated with the Cambrian aged Lakeview Formation. Small areas of

Rennie shale and Gold Creek quartzite occur with the Lakeview limestone.

Accessory Characteristics: The primary soils are moderately deep to deep.

They have silt loam surface soils overlying gravelly and cobbly loamy

subsoils. The vegetation is a coniferous forest. Mean annual precipitation

ranges from 75 to 88 centimeters (30 to 35 inches). The elevation range of

this LTA is 616 to 1280 meters (2000 to 4200 feet). The dominant slopes have

gradients of 10 to 50 percent. This LTA is moderately dissected by streams,

with the dominant stream pattern being parallel.

LTA Components: This landtype association consists of mountain slopes.

Mountain slopes are formed in limestone bedrock. Slope gradients range from 10

to 50 percent. Soils on these landforms are moderately deep to deep, and well

drained. They have a silt loam or loam surface layer underlain by very

gravelly to very cobbly sandy loam and loam subsurface layers. These soils are

classified as Andic Dystrochrepts and Typic Udivitrands. Rock outcrop occurs

on about 10 percent of this landscape component. The dominant potential

natural vegetation is Douglas-fir, grand fir, western redcedar and western

hemlock series. This component represents 100 percent of this LTA.

Compiled by: Gary Ford, Regional Office

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 359
LTA72-M333A

LTA72-M333B

LTA72-M333D

 FROST SHATTERED MOUNTAIN RIDGE TOPS: WEAKLY WEATHERED GRANITICS

Location: These units occur in the Selkirk, Purcell and Cabinet Mountains

of the Priest, Kootenai, Pack River and Clark Fork River basins of northeast

Idaho and northwest Montana. This unit is also located in the St. Joe

Mountains of the Bitterroot Range, which is part of the St. Joe and Little

North Fork of the Clearwater River basins of northern Idaho.

 Acreage by Section

 72-M333A 4,337

 72-M333B 968

 72-M333D 17,671

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a high elevation,

gentle to moderately steep sloping, mountain sideslope and ridge landscape

setting, which is typically composed of weakly to non dissected mountain

slopes, and associated ridges comprised of colluvium and residuum. Parent

materials are surface volcanic ash overlying weakly weatheredgranitics from

Cretaceous Kaniksu Batholith and Idaho Batholith.

Accessory Characteristics: The primary soils are shallow to deep sands, sandy

loams and loams, with up to 30 percent rock outcrop and scree on some units.

The vegetation is a mosaic of coniferous forest. Mean annual precipitation

ranges from 114 to 178 centimeters (45 to 70 inches). The elevation range of

this unit is 1433 to 1981 meters (4700 to 6500 feet). The dominant slopes have

gradients of 20 to 55 percent. This unit is weakly to non-dissected by

streams, with the dominant stream pattern being parallel when they occur.

LTA Components: This landtype association consists of weakly to non-dissected

mountain slopes and associated ridges,

Weakly to non-dissected mountain slopes and ridges occur on gentle to

moderately steep slopes and are formed in batholith that consists of granite,

granodiorite or other rocks of similar composition. The slope gradients range

from 10 to 60 percent. Soils on these landforms are shallow to deep, weakly

weathered and coarse to medium textured. The major soils are classified as

Vitric Haplocryands and Andic Cryochrepts. These soils make up the majority of

the unit and occur on the well drained sites. Vitric Fulvicryands and Andic

Cryumbrepts occur in the poorly drained sites. The shallow soils are

classified as Lithic Haplocryands and Lithic Cryochrepts. The dominant

potential natural vegetation series over most of the area is subalpine fir,

but mountain hemlock is dominant in the St. Joe and Little North Fork of the

Clearwater River basins. Minor Douglas-fir occurs on the very dry sites.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 360
CHAPTER 12

LTA Descriptions

Section M333B Flathead Valley

This Section occurs in northwest Montana and northern Idaho. It includes a

portion of the Continental Glaciated Mountains major geomorphic setting

previously described. Seventeen LTAs were mapped in this Section. See Appendix

F for a complete list of LTAs and their acreages. Map unit descriptions are

preceded by the following illustrations:

 Figure 50: Map showing location of M333B within the Northern Region

 Figure 51: M333B landscape photograph

 Ashley Lake and Salish Mountains, Flathead National Forest

 Figure 52: Map showing distribution of LTAS within M333B

 Figure 53: Bar chart showing abundance of landform groups within M333B

 Figure 54: Bar chart showing abundance of geologic material groups within

 M333B

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 361
LTA10-M333B

LTA10-M333C

LTA10-M333D

VALLEYS: RECENT COARSE ALLUVIUM

Location: This LTA is located in the inter-mountain valleys of the Flathead,

Clark Fork, and Kootenai River basins of northwest Montana.

 Acreage by Section

 

 10-M333B 191,377

 10-M333C 63,658

 10-M333D 160,219

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a valley bottom

landscape setting, which is composed of stream terraces, floodplains, and

alluvial basins. Parent materials are unstratified to stratified deposits of

sands, silts, and/or gravels underlain primarily by Proterozoic metasediments,

Cenozoic siltstones, and/or glacial deposits.

Accessory Characteristics: The primary soils are deep with extremely gravelly

coarse to medium textures. The vegetation is a mosaic of deciduous forest,

coniferous forest, and wet meadow/shrubland. Mean annual precipitation ranges

from 36 to 152 centimeters (14 to 60 inches). The elevation range of this LTA

is 758 to 1,970 meters (2500 to 6500 feet). The dominant slopes have gradients

of 3 to 15 percent. This LTA is moderately dissected by streams with the

dominant stream pattern being dendritic. Wetlands and river over-flow

channels are a major component of this LTA.

LTA Components: This landtype association consists of stream terrace,

floodplain, and alluvial basin landforms.

Stream terraces are formed in coarse, stratified alluvium. These terraces have

slope gradients that range from 0 to 15 percent. Soils on these landforms are

deep, poorly developed, and mostly of sand and gravel. The soils vary from

moderately well drained to well drained. The major soils on the moderately

well-drained sites are Oxyaquic Udifluvents, Typic Ustifluvents, and Typic

Udifluvents. The major soils on the well-drained sites are Dystric

Eutrochrepts, Andic Dystrochrepts and Typic Xerochrepts. Rock outcrops occur

less than 2 percent of the time. The dominant potential natural vegetation

series are black cottonwood, Engelmann spruce, western redcedar, grand fir,

Douglas-fir, and subalpine fir. This component represents 60 percent of the

LTA.

Floodplains and alluvial basins are formed in coarse stratified or

unstratified alluvium. These areas have slope gradients that range from 0 to

10 percent. Soils on these landforms are deep, weakly developed and consist

mostly of sand, gravel, and silt. These soils vary from moderately well

drained to poorly drained. The major soils are classified as Typic

Endoaquents, or Typic and Aeric Endoaquepts. Rock outcrops occur less than 1

percent of the time. The dominant potential natural vegetation series includes

subalpine fir, Engelmann spruce, and Drummond's willow. This component

represents 40 percent of the LTA.

Compiled by: Dean Sirucek, Flathead National Forest; Skip Barndt, Lolo

National Forest; Louis Kuennen, Kootenai National Forest.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 362
LTA11-M333B

LTA11-M333C

LTA11-M333D

VALLEYS: LACUSTRINE SEDIMENTS

Location: This unit is located in the inter-mountain valleys of the Clark

Fork, Flathead, and Kootenai River basins of northwest Montana.

 Acreage by Section

 11-M333B 533,326

 11-M333C 11,821

 11-M333D 111,455

LTA Setting and General Characteristics

Differentiating Characteristics: This unit occurs in a valley bottom

landscape setting, which is typically composed of glacial lacustrine deposits

that have level to slightly undulating topography. Parent materials consist of

stratified lake sediments of very fine sands, silts, and clays.

Accessory Characteristics: The primary soils are deep with medium to

moderately fine textures. The vegetation ranges from a continuous cover of

coniferous vegetation on the well drained sites to wet meadow/shrubland on the

poorly drained sites. Mean annual precipitation ranges from 36 to 152

centimeters (14 to 60 inches). The elevation range is 758 to 1,818 meters

(2500 to 6000 feet). The dominant slopes have gradients of 2 to 20 percent. 

This map unit is slightly dissected by streams. Where present, the dominant

stream pattern is dendritic. Wetlands and ponds are a major component of the

unit.

LTA Components: This landtype association consists of lacustrine terraces and

lacustrine basins.

Lacustrine terraces and lacustrine basins are formed in stratified lake

sediments. These landforms have dominant slope gradients ranging from 0 to 25

percent. Included with these landforms are terrace risers/scarps that have

slopes that range from 40 to 70 percent. Soils on these landforms are deep,

weak to moderately developed with medium and moderately fine textures. In

northwestern Montana the major soils on the forested, welll -drained sites are

classified as Glossic Cryoboralfs or Typic Eutroboralfs, and Eutric

Glossoboralfs. In Section M333B additional major soils are Andic/Typic

Dystrochrept. The lower elevation, non-forested, valleys the soils are

classified as Typic Natrixeralfs and Typic Xerochrept. The dominant potential

vegetation series include western redcedar, subalpine fir, grand fir, and

Douglas-fir. The major soils on the poorly drained sites are classified as

Aeric Epiaquepts and Aquic Eutroboralfs with inclusions of Typic Borosaprists.

Rock outcrop occurs on less than 2 percent of this landscape component. 

Engelmann spruce and Drummond's willow occur on the poorly drained sites.

Compiled by: Dean Sirucek, Flathead National Forest; Skip Barndt, Lolo

National Forest; Louis Kuennen, Kootenai National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 363
LTA12-M333B

LTA12-M333C

LTA12-M333D

VALLEYS: OUTWASH AND OTHER OLDER COARSE ALLUVIAL DEPOSITS

Location: This map unit is located in the inter-mountain valleys of the Clark

Fork, Flathead, and Kootenai River basins of northwest Montana.

 Acreage by Section

 12-M333B 428,208

 12-M333C 97,651

 12-M333D 181,889

LTA Setting and General Characteristics

Differentiating Characteristics: This unit occurs in valley bottom landscape

settings, which are typically composed of glacial outwash plains or outwash

terraces that have undulating surfaces. Steep escarpments form the front of

the some of the terraces. Parent materials consist of either stratified or

unstratified glacial fluvial deposits of sand and gravel material. These

deposits are typically underlain by glacial moraine deposits or Proterozoic

metasedimentary bedrock.

Accessory Characteristics: The primary soils are deep with extremely gravelly

coarse textures. These soils are typically excessively well drained with

inclusions of poorly drained soils. The vegetation is primarily coniferous

forest with areas of wet meadow/shrubland. Mean annual precipitation ranges

from 36 to 140 centimeters (14 to 55 inches). The elevation range of this unit

is 758 to 1,667 (2500 to 5500 feet). The dominant slopes have gradients of 2

to 20 percent. This map unit is moderate to highly dissected by streams or

rivers with the dominant stream pattern being dendritic. Wetlands and riparian

areas are important components of this unit.

LTA Components: This landtype association consists of glacial outwash plains

and outwash terraces.

These glacial outwash plains and outwash terraces are formed in coarse,

stratified or unstratified glacial fluvial sediments. Slope gradients range

from 0 to 25 percent with gradients up to 50 percent on the terrace risers.

Soils on these landforms are deep, weakly developed with extremely gravelly

coarse textures. The major soils are classified as Dystric Eutrochrepts, 

Typic Dystrochrept, Andic Dystrochrepts, and Andic Ustochrepts. Rock outcrop

occurs on less than 5 percent of this map unit. The dominant potential

vegetation series include Douglas-fir, western redcedar, subalpine fir, and

Engelmann spruce.

Compiled by: Dean Sirucek, Flathead National Forest; Skip Barndt, Lolo

National Forest; Louis Kuennen. Kootenai National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 364
LTA14-M333B

LTA14-M333C

VALLEYS: RECENT FINE ALLUVIUM

Location: This LTA is located in the inter-mountain valleys of the Flathead

River basin in northwest Montana.

 Acreage by Section

 14-M333B 33,343

 14-M333C 5,120

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a valley bottom

landscape setting, which is composed of stream terraces, floodplains, and

alluvial basins. Parent materials are stratified deposits of fine sands,

silts, and clays with or without gravels. These deposits are underlain

primarily by Cenozoic siltstones and glacial deposits.

Accessory Characteristics: The primary soils are deep with medium or

moderately fine textures. The vegetation is a mosaic of deciduous forest,

coniferous savanna, grassland, and wet meadow/shrubland. Mean annual

precipitation ranges from 30 to 51 centimeters (12 to 20 inches). The

elevation range of this LTA is 745 to 1,067 (2460 to 3500 feet). The dominant

slopes have gradients of 0 to 10 percent. This LTA is moderately dissected by

streams with the dominant stream pattern being dendritic. Wetlands and river

over-flow channels are a major component of this LTA.

LTA Components: This landtype association consists of stream terraces,

floodplains, and alluvial basins.

Stream terraces are formed in stratified alluvium. These terraces have slope

gradients that range from 0 to 10 percent. Soils on these landforms are deep,

poorly developed, and coarse to moderately fine textured. These soils are

classified as Typic Ustifluvents, Udic Haploborolls, and Typic Eutrochrepts.

Rock outcrops occur less than 1 percent of the time. The dominant potential

natural vegetation series include ponderosa pine and rough fescue. This

component represents 85 percent of the LTA.

Floodplains and alluvial basins are formed in stratified recent alluvium.

These areas have slope gradients that range from 0 to 10 percent. Soils on

these landforms are deep, weakly developed with medium to moderately- fine

textures. The major soils are classified as Fluvaqentic Haploxerolls, or Typic

and Aeric Endoaquepts. Rock outcrops occur less than 1 percent of the time.

The dominant potential natural vegetation series include ponderosa pine,

Engelmann spruce, and Geyer willow. This component represents 15 percent of

the LTA.

Compiled by: Dean Sirucek, Flathead National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 365
LTA20-M333B

LTA20-M333C

LTA20-M333D

BREAKS: METASEDIMENTARY (BELT)

Location: This unit is located in the Whitefish, Swan, Mission, Bitterroot,

Purcell, Salish, Cabinet, and Flathead mountain ranges of the Clark Fork,

Flathead, and Kootenai River basins in northwest Montana.

 Acreage by Section

 20-M333B 212,411

 20-M333C 163,793

 20-M333D 1,000,850

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in both the upland and

alpine landscape settings, which are typically composed of structural

breakland and stream breakland landforms. Parent materials are volcanic ash

overlying weakly-weathered, moderately metamorphosed, Proterozoic

metasedimentary bedrock composed of argillites, siltites, quartzites,

limestone and dolomites.

Accessory Characteristics: The primary soils are shallow to moderately deep

with very gravelly medium textures. The vegetation is a mosaic of coniferous

forest, and mountain shrub/grass lands. Mean annual precipitation ranges from

41 to 229 centimeters (16 to 90 inches). The elevation range is 697 to 2,590

(2300 to 8500 feet). The dominant slopes have gradients of 55 to 70 percent.

This unit is slightly to moderately dissected by streams with the dominant

stream patterns being sub-parallel and parallel. Major streams or rivers are

typically located at the base of stream breaks. Lakes and ponds are a minor

component of this unit.

LTA Components: This landtype association consists of structural and stream

breaks.

Structural breaks are formed in colluvial materials from weakly weathered

metasedimentary bedrock. Slope gradients range from 50 to 100 percent. Soils

on these landforms are shallow to moderately deep, weakly developed, with very

gravelly medium textures. These soils are classified as Lithic, Typic and

Andic Dystrochrepts, and Lithic, Typic, and Andic Cryochrepts on colder sites.

Rock outcrop and talus occur on 20 to 80 percent of this landscape component.

The dominant potential natural vegetation series on the warmer sites is

Douglas-fir. On the cooler sites it is subalpine fir, or whitebark

pine-subalpine fir. This component represents 80 percent of this unit.

Stream breaks are formed in colluvial materials from weakly weathered

metasedimentary bedrock. Slope gradients range from 50 to 90 percent. Soils on

these landforms are shallow to moderately deep and weakly developed with very

gravelly medium textures. These soils are classified as Lithic and Typic

Dystrochrepts on the warmer sites; and Lithic, Typic and Andic Cryochrepts on

the cooler sites. Rock outcrop and talus occur on 20 to 60 percent of this

landscape component. The dominant potential natural vegetation series is

Douglas-fir on the warmer sites and subalpine fir on the cooler sites. This

component represents 20 percent of this unit.

Compiled by: Dean Sirucek, Flathead National Forest; Skip Barndt, Lolo

National Forest; Louis Kuennen, Kootenai National Forest.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 366
LTA40-M333B

LTA40-M333C

LTA40-M333D

STEEP GLACIATED MOUNTAIN SLOPES: METASEDIMENTARY (BELT)

Location: This map unit is located in the Bitterroot, Cabinet, Purcell,

Salish, Swan, Mission, Flathead, and Whitefish Mountain ranges of the Clark

Fork, Flathead and Kootenai basins in northwest Montana.

 Acreage by Section

 40-M333B 221,169

 40-M333C 1,637,034

 40-M333D 222,209

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in an upland and alpine

landscape settings, which are primarily composed of glacial troughwall, cirque

headwall, and cirque basin landforms. Parent materials are alpine glacial

debris and colluvium derived from and underlain by moderately metamorphosed,

Proterozoic metasediments composed of argillite, siltite, quartzite, limestone

and dolomite bedrocks. Inclusions of other bedrocks such as granite occur in

this map unit.

Accessory Characteristics: The primary soils are shallow to moderately deep,

with cobbly or gravelly medium textures. The vegetation is a mosaic of

coniferous forest, alpine meadows, and shrubland associated with avalanche

chutes. Mean annual precipitation ranges from 102 to 305 centimeters (40 to

120 inches). The elevation range of this unit is 1,212 to 3,182 meters (4000

to 10,500 feet. The dominant slopes range from 50 to 90 percent. The cirque

basin portion of the map unit has slopes that range from 5 to 40 percent. The

troughwall landforms are moderately to highly dissected by streams with the

dominant stream pattern being parallel. The cirque headwall and cirque basin

landforms are weakly dissected by streams with the dominant stream pattern

being parallel. Wetlands are associated with the cirque basins, and occur as a

minor component of this unit.

LTA Components: This landtype association consists primarily of glacial

troughwalls, cirque headwalls, and cirque basins.

Glacial troughwalls are formed in glacial tills on the lower elevation slopes

with volcanic ash influenced colluvium on the higher elevation slopes. Slope

gradients range from 50 to 90 percent. Soils on the lower slopes of this

landform are moderately shallow to deep and are moderate to highly developed,

with cobbly medium textures. The major soils on the lower slopes are

classified as Andeptic and Typic Cryoboralfs. Soils on the upper slopes of

this landform are shallow to moderately deep, are moderately developed, and

have gravelly medium textures. The major soils on the higher slopes are Andic,

Typic, and Lithic Cryochrepts. Rock outcrops occupy up to 15 percent of the

area. The dominant potential natural vegetation series are grand fir, western

redcedar, Douglas-fir, and subalpine fir on the lower slopes; and subalpine

fir and mountain hemlock on the upper slopes. This component represents 55

percent of the LTA.

Cirque headwalls/cirque basins are formed in glacial till on the lower

elevation slopes and volcanic ash influenced colluvium on the higher elevation

slopes. Included in this alpine landscape setting are small areas of alpine

ridge landforms. Slope gradients range from 5 to 90 percent. Soils on these

landforms are shallow to moderately deep and weakly developed, with very

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 367
gravelly medium textures. The major soils are classified as Lithic Cryochrepts

and Andic Cryochrepts. Rock outcrops occupy more than 40 percent of the area.

The dominant potential natural vegetation series include subalpine fir, and

whitebark pine-subalpine fir. This component represents 45 percent of the LTA.

Compiled by: Dean Sirucek, Flathead National Forest; Louis Kuennen, Kootenai

National Forest; Skip Barndt, Lolo National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 368
LTA47-M333B

ALPINE TROUGHS AND TROUGHWALLS: METASEDIMENTARY (BELT)

Location: This unit is located in the Purcell and Cabinet Mountains of the

Kootenai, Pack River and Clarkfork River basins of northeast Idaho and

northwest Montana.

 Acreage by Section

 47-M333B 27,452

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs at the higher

elevations, in a gentle to steep alpine glacial setting, which is typically

composed of alpine trough bottoms and troughwalls. Parent materials are

surface volcanic ash overlying weakly weathered tills consisting of

quartzites, siltites and argillites from Precambrian metasedimentary bedrock.

Accessory Characteristics: The primary soils are shallow to deep sandy loams

and loams, with inclusions of rock outcrop, scree and avalanche chutes. The

vegetation is a mosaic of coniferous forest. Mean annual precipitation

ranges from 127 to 229 centimeters (50 to 90 inches). The elevation range of

this unit is 1372 to 2286 meters (4500 to 7500 feet). The dominant slopes

range from 1 percent in the trough bottoms to 85 percent on the steeper

troughwalls. This unit is slightly to highly dissected by streams, with the

dominant stream pattern being parallel. Wet sidehill areas and grassy parks

are a component of this LTA.

LTA Components: This landtype association consists of glacial troughwalls and

glacial trough bottoms.

These moderately steep to steep glaciated troughwalls consist of glacial till

from metasedimentary bedrock sources. The slope gradients range from 40 to 85

percent. Soils on these landforms are shallow to deep, weakly weathered and

medium textured. The major soils on the well drained sites are classified as

Vitric Haplocryands and Typic Cryochrepts. Lithic Cryochrepts are scattered

throughout. Vitric Fulvicryands and Aquic Cryochrepts occur in the more poorly

drained sites. Rock outcrop and scree occurs as an inclusion in this unit. The

dominant potential natural vegetation is the subalpine fir series. This

component represents about 70 percent of this unit.

The trough bottoms consist of deep glacial tills and glacio-fluvial materials

from metasedimentary bedrock sources. The slope gradients range from 1 to 40

percent. Soils on these landforms are moderately deep to deep, weakly

weathered and medium textured. The major soils on the well drained sites are

classified as Vitric Haplocryands and Typic Cryochrepts. Vitric Fulvicryands

and Aquic Cryochrepts occur in depressional area and other poorly drained

sites. The dominant potential natural vegetation is the subalpine fir series.

This component represents about 30 percent of this unit.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 369
LTA50-M333B

LTA50-M333D

GLACIATED MOUNTAIN SLOPES: METASEDIMENTARY (BELT)

Location: This map unit is located primarily in the Flathead, Clark Fork and

Kootenai River basins of the Salish, Purcell, Bitterroot, and Cabinet

Mountains of northwest Montana.

 Acreage by Section

 50-M333B 2,681,456

 50-M333D 66,747

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in both valley and

upland settings mainly within a continentally glaciated landscape. Parent

materials are continental and/or alpine glacial debris underlain by

Proterozoic metasediments composed of argillites, siltites, limestones, and

quartzites.

Accessory Characteristics: The primary soils are moderately shallow to very

deep, very gravelly coarse silt and fine sandy loams. The major vegetative

cover is a dense coniferous forest with occasional grassy openings. Mean

annual precipitation ranges from 36 to 178 centimeters (14 to 70 inches). The

elevation range is 667 to 1667 meters (2200 to 5500 feet). The dominant slopes

range from 20 to 50 percent. This map unit is slightly to moderately dissected

by streams with the dominant stream pattern being dendritic. Bogs are a minor

component of this map unit.

LTA Components: This landtype association has the classic subdued glacial

landforms which are comprised of convex, scoured ridges and sideslopes, and

valleys with deeper soils.

The straight side slopes and valleys are composed of a rounded ridges and

filled in valleys landform. These areas have slopes that range from 5 to 60

percent. The ridges were strongly scoured and then covered by glacial debris.

The drainage bottoms were filled in. The landforms (straight mountain slopes

and concave lower side slopes) have soils that are moderately deep to very

deep consisting of rock, fine sand and coarse silt. The major soils are

classified as Andic Dystrochrepts, Typic Dystrochrepts, Typic Eutrochrepts,

Typic Ustochrepts, Dystric Cryochrepts, and Andic Dystric Eutrochrept. Rock

outcrops occupy less than 15 percent of the area. This landform is covered

with a dense forest cover. The dominant potential natural vegetation series

include western redcedar, western hemlock, subalpine fir, and Douglas-fir. 

This component represents 65 percent of the unit.

The ridge top landform is comprised of the convex feature of the landscape.

The soils on this part of the landscape are moderately shallow to shallow. 

The major soils are classified as Lithic, Typic, and Andic Cryochrepts. The

dominant potential natural vegetation series is subalpine fir. This component

represents 35 percent of the map unit.

Compiled by: Louis Kuennen, Kootenai National Forest and Skip Barndt, Lolo

National Forest.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 370
LTA51-M333B

GLACIATED MOUNTAIN SLOPES: GRANITICS

Location: This unit is located in the Purcell and Cabinet Mountains of the

Kootenai and Pack River Basins of northeast Idaho.

 Acreage by Section

 51-M333B 90,791

LTA Unit Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a gentle to

moderately steep valley bottom, mountain sideslope and ridge landscape setting

at elevations that range from low to high. The unit is typically composed of

dissected and non dissected mountain slopes, valleys and ridges comprised of

alpine and continental till. Parent materials are surface volcanic ash

overlying substratum materials of glacial tills derived from Cretaceous

Kaniksu Batholith bedrock.

Accessory Characteristics: The primary soils are shallow to deep sands, with

a small component of rock outcrop and scree. The vegetation is a mosaic of

coniferous forest. Mean annual precipitation ranges from 64 to 127 centimeters

(25 to 50 inches). The elevation range of this unit is 731 to 1737 meters

(2400 to 5700 feet). The dominant slopes have gradients of 15 to 55 percent.

This unit is slightly to highly dissected by streams, with the dominant stream

pattern being parallel. 

LTA Components: This landtype association consists of dissected and

non-dissected, continentally glaciated, convex ridges and concave valleys.

The glaciated convex ridges and mountain sideslopes were strongly scoured and

then covered by varying thickness of glacial tills. The slope gradients range

from near level to 60 percent. The drainage bottoms and toeslopes consist of

deep glacial tills and glacio-fluvial materials. The slope gradients range

from 0 to 40 percent. Soils on the ridge and mountain sideslopes landforms are

shallow to deep, weakly weathered, and sandy textured. Soils in the drainage

bottoms and toeslopes are deep, weakly weathered, and sandy textured. The

major soils on the well drained sites are classified as Andic Cryochrepts and

Andic Dystrochrepts, with Andic Xerochrepts on the drier sites. The areas with

deeper ash caps are Vitric Haplocryands and Typic Udivitrands. Andic

Cryumbrepts-Andic Haplumbrepts occur in the more poorly drained sites. Rock

outcrop and scree occurs as an inclusion in the scoured ridge and mountain

sideslope landforms. The dominant potential natural vegetation series on the

well drained, high elevation sites is subalpine fir with western hemlock,

western red cedar and Douglas-fir occurring at low to mid elevations. The

dominant potential natural vegetation series on the poorly drained sites are

subalpine fir at the higher elevations and in cold air pockets at lower

elevations, and western red cedar at the mid and lower elevations.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 371
LTA53-M333B

LTA53-M333C

LTA53-M332B

GLACIATED MOUNTAIN SLOPES: SANDSTONES, SHALES, AND CARBONATES

Location: This map unit is located in of the Swan, Mission, Flathead, and

Whitefish mountain ranges of the Flathead, Clearwater, and Blackfoot River

basins in northwest Montana.

 Acreage by Section

 53-M333B 8,091

 53-M333C 100,613

 53-M332B 6,924

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in both valley bottom

and upland landscape settings, which are primarily composed of glacial moraine

landforms. Parent materials are continental or alpine glacial debris with or

without volcanic ash surface layers; underlain by Paleozoic and Mesozoic

sandstone, shale, and limestone bedrocks. In the North Fork of the Flathead

River areas of Tertiary siltstone are included in this map unit.

Accessory Characteristics: The primary soils are moderately deep to very

deep, with gravelly medium and moderately fine textures. The major vegetative

cover is a dense coniferous forest with occasional meadow openings. Mean

annual precipitation ranges from 51 to 178 centimeters (20 to 70 inches). The

elevation range is 1,036 to 2,316 (3400 to 7600 feet). The dominant slopes

range from 5 to 50 percent. This map unit is moderately to highly dissected by

streams, with the dominant stream pattern being dendritic. Wetlands are a

minor component of this unit.

LTA Components: This landtype association consists primarily of glacial

moraines. Glacially scoured ridge top landforms occur as a minor component.

On the valley bottom landscape setting the glacial moraines occur on rolling

hummocky topography, with slopes that range from 5 to 30 percent slope. On

the upland landscape setting the glacial moraines occur on straight to

slightly concave slopes, with range from 20 to 55 percent in gradient. These

glacial moraines typically occur as the toe-slope associated with glacial

troughwalls. Soils on these landforms are moderately deep to very deep, and

are moderate to highly developed, with gravelly moderately-fine or fine

textures. The major soils are classified as Typic Eutrochrepts and Andeptic

Cryoboralfs. Rock outcrops occupy less than 15 percent of the area. The

dominant potential natural vegetation is Douglas-fir and subalpine fir.

A minor component of this map unit is glacially scoured ridge tops. Slope

gradients range from 5 to 20 percent. Soils on these landforms are shallow to

moderately deep, moderately developed, with gravelly medium textures. The

major soils are classified as Andic Cryochrepts. Rock outcrops occupy less

than 15 percent of the area. The dominant potential natural vegetation is

subalpine fir and Douglas-fir. This component represents 15 percent of this

map unit.

Compiled by: Dean Sirucek, Flathead National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 372
LTA58-M333B

LTA58-M333C

GLACIATED MOUNTAIN SLOPES: HIGHLY WEATHERED METASEDIMENTARY TILL

Location: This map unit is located in the Whitefish, Mission, Swan, Purcell,

Salish, Cabinet, and Flathead mountain ranges of the Flathead, Kootenai, and

Swan River basins in northwest Montana.

 Acreage by Section

 58-M333B 164,491

 58-M333C 20,031

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in both upland and

valley bottom landscape settings, which are typically composed of glacial

moraine landforms. Parent materials are alpine or continental glacial debris

deposited during Pre-Wisconsin glacial periods. These deposits are underlain

by moderately metamorphosed, Proterozoic metasedimentary bedrock composed of

argillites, siltites, dolomites, limestones, and quartzites; or Tertiary

siltstones.

Accessory Characteristics: The primary soils are moderately deep to very deep

very gravelly coarse silt/fine sandy loams. The major vegetative cover is a

dense coniferous forest with occasional grassy openings. Mean annual

precipitation ranges from 51 to 152 centimeters (20 to 60 inches). The

elevation range of this LTA is 667 to 1,707 meters (2200 to 5600 feet). The

dominant slopes range from 20 to 50 percent. This map unit is moderately to

highly dissected by streams with the dominant stream pattern being dendritic.

Wetlands are a minor component of this map unit.

LTA Components: This landtype association consists primarily of glacial

moraines.

The landscape setting for this map unit varies from a valley bottom to a

moderately steep upland setting. In the valley bottom landscape setting the

glacial moraines occur on rolling, hummocky topography, with slopes that range

from 5 to 30 percent slope. In the upland landscape setting the glacial

moraines occur on straight to slightly concave slopes that range from 20 to 55

percent in gradient. These glacial moraines typically occur as the to-slope e

associated with glacial troughwalls.

Soils on these landforms are moderately deep to very deep and are moderate to

highly developed with gravelly moderately-fine or fine textures. The major

soils are classified as Typic Glossoboralfs, Typic Eutroboralfs, and Andeptic

Cryoboralfs. Rock outcrops occupy less than 5 percent of the area. The

dominant potential natural vegetation series include western redcedar, grand

fir, subalpine fir and Douglas-fir.

Compiled by: Dean Sirucek, Flathead National Forest; Louis Kuennen, Kootenai

National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 373
LTA60-M333B

LTA60-M333C

MOUNTAIN SLOPES AND RIDGES: METASEDIMENTARY (BELT)

Location: This unit is located in the Whitefish, Swan, Purcell, Cabinet,

Salish, Mission, and Flathead Mountain ranges of the Flathead, Kootenai, and

Swan River basin in northwest Montana.

 Acreage by Section

 60-M333B 497,972

 60-M333C 114,155

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in both the upland and

alpine landscape settings, which are typically composed of dissected mountain

slope, glaciated mountain slope, and glacially scoured ridge top landforms.

The geomorphic processes that occur on these areas include: colluvial, fluvial

and glacial, erosion or deposition. Parent materials are volcanic ash

overlying weakly weathered, moderately metamorphosed Proterozoic

metasedimentary bedrock composed of argillites, siltites, quartzites, and

limestones.

Accessory Characteristics: The primary soils are shallow to moderately deep

with very gravelly medium textures. The vegetation is a mosaic of coniferous

forest, mountain shrublands, and mountain grasslands. Mean annual

precipitation ranges from 46 to 203 centimeters (18 to 80 inches). The

elevation range is 758 to 2,286 meters (2500 to 7500 feet). The dominant

slopes have gradients of 15 to 50 percent. This unit is moderate to strongly

dissected by streams with the dominant stream patterns being dendritic and

sub-parallel.

LTA Components: This landtype association consists of glacially scoured ridge

tops and dissected mountain slopes (fluvial) with inclusions of glaciated

mountain slopes.

Glacially scoured ridge tops have been strongly modified by continental ice.

The prominent features are ridge tops and ridge noses with exposed bedrock.

These areas have slopes that range from 10 to 45 percent. Soils on these

landforms are shallow to moderately deep and weak to moderately developed with

medium textures. The major soils are classified as Lithic, Andic or Typic

Cryochrepts, and Typic and Lithic Dystrochrepts. Rock outcrops occupy more

than 50 percent of the area. The dominant potential natural vegetation series

includes subalpine fir, subalpine fir-whitebark pine, and Douglas-fir. This

landform component makes up 50 percent of the LTA.

The dissected mountain slopes (fluvial) landscape is one that is

weathering-in-place. It is chemical weathering further affected by colluvial

action. Slope gradients range from 30 to 60 percent. Soils on these landforms

are moderately deep to deep, with weak to moderate development, and gravelly

medium textures. The major soils are classified as Andic Cryochrepts, Andeptic

and Typic Cryoboralfs, and Typic or Argic Cryoborolls, Typic Haploborolls and

Typic Dystrochrept. Rock outcrops occupy less than 10 percent of the area. The

dominant potential natural vegetation series includes Douglas -fir and

subalpine fir. This landform component represents 50 percent of the LTA.

Compiled by: Dean Sirucek, Flathead National Forest; Louis Kuennen, Kootenai

National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 374
LTA64-M333B

MOUNTAIN SLOPES AND RIDGES: VOLCANIC

Location: This LTA is located primarily in the Salish Mountain Range of the

Flathead River Basin in northwest Montana.

 Acreage by Section

 64-M333B 19,044

LTA Setting and General Characteristics

Differentiating characteristics: This LTA occurs in an upland landscape

setting which is typically composed of dissected mountain slope, glaciated

mountain slope, and glacially scoured ridge top landforms. Parent materials

are Tertiary volcanic bedrock composed of welded tuff or basalt. This unit has

inclusions of Tertiary intrusive bedrock composed on granodiorite of granite.

The soil material is weathering in place.

Accessory Characteristics: The primary soils are shallow to moderately deep

with very gravelly medium and moderately coarse textures. The vegetation is a

mosaic of coniferous forest and mountain grasslands. Mean annual precipitation

ranges from 41 to 102 centimeters (16 to 40 inches). The elevation range is

853 to 1,584 meters (2800 to 5200 feet). The dominant slopes have gradients of

15 to 55 percent. This unit is moderately to strongly dissected by streams

with the dominant stream patterns being dendritic and sub-parallel.

LTA Components: This landtype association consists of glacially scoured ridge

tops and dissected mountain slopes (fluvial) with inclusions of glaciated

mountain slopes.

Glacially scoured ridge tops have been strongly modified by continental ice.

The prominent features are ridge tops and ridge noses with exposed bedrock.

These areas have slopes that range from 10 to 45 percent. Soils on these

landforms are shallow to moderately shallow, are weakly to moderately

developed, and have medium and moderately fine textures. The major soils are

classified as Lithic Cryochrepts, and Typic and Lithic Haploxerolls. Rock

outcrops occupy more than 50 percent of the area. The dominant potential

natural vegetation series include subalpine fir, rough fescue, and

Douglas-fir. This landform component makes up 40 percent of the LTA.

The dissected mountain slopes (fluvial) landscape is one that is weathering in

place. It is chemical weathering further affected by colluvial action. Slope

gradients range from 30 to 60 percent. Soils on these landforms are moderately

deep to deep, with moderate to high development, and have gravelly to very

gravelly medium textures. The major soils are classified as Typic Argixeroll,

Glossic Eutroboralfs, and Typic Ustochrepts. Rock outcrops occupy less than 10

percent of the area. The dominant potential natural vegetation series includes

Douglas-fir and subalpine fir. This landform component represents 60 percent

of the LTA.

Compiled by: Dean Sirucek, Flathead National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 375
LTA68-M333B

LTA68-M333C

LTA68-M333D

MOUNTAIN SLOPES AND RIDGES: SANDSTONES, SHALES AND CARBONATES

Location: This unit is located in the Whitefish, Swan, and Flathead mountain

ranges of the Flathead, Clearwater, and Blackfoot River basins in northwest

Montana.

 Acreage by Section

 68-M333B 8,043

 68-M333C 36,067

 68-M333D 1,511

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in both upland and

alpine landscape settings, which are typically composed of dissected mountain

slopes, glaciated mountain slopes, and glacially scoured ridge top landforms.

Colluvial, fluvial and glacial, erosional/depositional geomorphic processes

occur in these areas. Parent materials are volcanic ash overlying weakly

weathered Paleozoic and Mesozoic sandstone, shale, and limestone bedrock.

Accessory Characteristics: The primary soils are shallow to moderately deep

with very gravelly medium and moderately fine textures. The vegetation is a

mosaic of coniferous forest, mountain shrubland, and mountain grassland. Mean

annual precipitation ranges from 51 to 177 centimeters (20 to 70 inches). The

elevation range is 1,219 to 2,134 meters (4000 to 7000 feet). The dominant

slopes have gradients of 55 to 70 percent. This unit is moderate to strongly

dissected by streams with the dominant stream patterns bein g dendritic and

sub-parallel.

LTA Components: This landtype association consists of glacially scoured ridge

tops and dissected mountain slopes (fluvial) with inclusions of glaciated

mountain slopes.

Glacially scoured ridge tops have been strongly modified by continental ice.

The prominent features are ridge tops and ridge noses with exposed bedrock.

These areas have slopes that range from 10 to 45 percent. Soils on these

landforms are shallow to moderately deep, weak to moderately developed with

medium and moderately fine textures. The major soils are classified as Lithic 

Andic, or Typic Cryochrepts. Rock outcrops occupy more than 50 percent of the

area. The dominant potential natural vegetation is subalpine fir-whitebark

pine, and subalpine fir. This landform component makes up 40 percent of the

LTA.

The dissected mountain slopes (fluvial) landscape is one that is

weathering-in-place. It is chemical weathering further affected by colluvial

action. Slope gradients range from 30 to 60 percent. Soils on these landforms

are moderately deep to deep, weak to moderate development, with medium and

moderately fine textures. The major soils are classified as Andic Cryochrepts,

Andeptic and Typic Cryoboralfs, and Typic or Argic Cryoborolls. Rock outcrops

occupy less than 10 percent of the area. The dominant potential natural

vegetation is Douglas-fir and subalpine fir. This landform component

represents 60 percent of the LTA.

Compiled by: Dean Sirucek, Flathead National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 376
LTA70-M333B

LTA70-M333C

LTA70-M333D

FROST SHATTERED MOUNTAIN RIDGE TOPS: METASEDIMENTARY (BELT)

Location: This unit is located in the Whitefish, Cabinets, Purcell, Salish,

Bitterroot, Swan, Mission, and Flathead Mountain ranges of the Clark Fork,

Pack River, Kootenai, and Flathead River basins in northwest Montana and north

Idaho.

 Acreage by Section

 70-M333B 153,508

 70-M333C 60,686

 70-M333D 518,308

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in an alpine landscape

setting and is typically composed of a ridge top landform which has formed by

frost shattering. Parent materials are volcanic ash overlying weakly

weathered, moderately metamorphosed, Proterozoic metasedimentary bedrock

composed of argillites, siltites, quartzites, dolomites, and limestones. There

are inclusions of other types of bedrock such as granite in this map unit.

Accessory Characteristics: The primary soils are shallow to moderately deep

with very gravelly medium textures. The vegetation is a mosaic of coniferous

forest, mountain shrubland, and mountain grasslands. Mean annual precipitation

ranges from 102 to 279 centimeters (40 to 110 inches). The elevation range is

1,341 to 2,758 (4400 to 9100 feet). The dominant slopes have gradients of 20

to 60 percent. This map unit is undivided to slightly dissected by streams,

with the pattern being dendritic or parallel where present.

LTA Components: This landtype association consists of glacially scoured,

frost shattered ridge tops.

Glacially scoured, frost shattered ridge tops have been strongly modified by

continental ice, alpine ice, and frost action. The prominent features are

ridge tops that have been rounded or scoured by the previously mentioned

actions. Exposed bedrock comprises 10 to 40 percent of the area. These areas

have slopes that range from 5 to 70 percent. Soils on these landforms are

shallow to moderately deep and weakly developed with very gravelly medium

textures. The major soils are classified as Lithic Cryochrepts, Lithic

Haplocryands, Vitric Haplocryands, and Andic Cryochrepts. Vitric Fulvicryands

and Andic Cryumbrepts occur in the poorly drained sites. The dominant

potential natural vegetation includes subalpine fir, mountain hemlock, and

whitebark pine-subalpine fir series. This landform component makes up 90

percent of the map unit. There are up to 10 percent inclusions of nivation

hollows that occur in this map unit.

Compiled by: Dean Sirucek, Flathead National Forest; Louis Kuennen, Kootenai

National Forest; Skip Barndt, Lolo National Forest, Jerry Niehoff, Idaho

Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 377
LTA72-M333B

LTA72-M333A

LTA72-M333D

FROST SHATTERED MOUNTAIN RIDGE TOPS: WEAKLY WEATHERED GRANITICS

Location: This unit is located in the Selkirk, Purcell and Cabinet Mountains

of the Priest, Kootenai, Pack River and Clark Fork River basins of northeast

Idaho and northwest Montana. This unit is also located in the St. Joe

Mountains of the Bitterroot Range, which is part of the St. Joe and Little

North Fork of the Clearwater River basins of northern Idaho.

 Acreage by Section

 72-M333A 4,337

 72-M333B 967

 72-M333D 17,671

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a high elevation,

gentle to moderately steep sloping, mountain sideslope and ridge landscape

setting, which is typically composed of weakly to non dissected mountain

slopes, and associated ridges comprised of colluvium and residuum. Parent

materials are surface volcanic ash overlying weakly weathered granitics from

Cretaceous Kaniksu Batholith and Idaho Batholith.

Accessory Characteristics: The primary soils are shallow to deep sands, sandy

loams and loams, with up to 30 percent rock outcrop and scree on some units.

The vegetation is a mosaic of coniferous forest. Mean annual precipitation

ranges from 114 to 178 centimeters (45 to 70 inches). The elevation range of

this unit is 1433 to 1981 meters (4700 to 6500 feet). The dominant slopes have

gradients of 20 to 55 percent. This unit is weakly to non-dissected by

streams, with the dominant stream pattern being parallel when they occur.

LTA Components: This landtype association consists of weakly to non-dissected

mountain slopes and associated ridges,

Weakly to non-dissected mountain slopes and ridges occur on gentle to

moderately steep slopes and are formed in batholith that consists of granite,

granodiorite or other rocks of similar composition. The slope gradients range

from 10 to 60 percent. Soils on these landforms are shallow to deep, weakly

weathered and coarse to medium textured. The major soils are classified as

Vitric Haplocryands and Andic Cryochrepts. These soils make up the majority of

the unit and occur on the well drained sites. Vitric Fulvicryands and Andic

Cryumbrepts occur in the poorly drained sites. The shallow soils are

classified as Lithic Haplocryands and Lithic Cryochrepts. The dominant

potential natural vegetation series over most of the area is subalpine fir,

but mountain hemlock is dominant in the St. Joe and Little North Fork of the

Clearwater River basins. Minor Douglas-fir occurs on the very dry sites.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 378
LTA90-M333B

LTA90-M333C

MASS WASTED SLOPES: MIXED GEOLOGY

Location: This unit is located in the Swan, Salish, Flathead, Mission, and

Whitefish Mountain ranges of the Swan and Flathead River basins in northwest

Montana.

 Acreage by Section

 90-M333B 1,358

 90-M333C 58,472

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in both upland and

alpine landscape settings. Typically landslide areas are associated with

structural breakland, stream breakland, glacial troughwall, and glacial

moraine landforms. Parent materials are typically glacial tills underlain by

Paleozoic and Mesozoic sandstone and shale bedrock; or Proterozoic argillite,

siltite, quartzite, dolomite and limestone.

Accessory Characteristics: The primary soils are moderately deep to deep with

gravelly medium to moderately fine textures. The vegetation is primarily

coniferous forest with inclusions of shrublands. Mean annual precipitation

ranges from 51 to 229 centimeters (20 to 90 inches). The elevation range is

914 to 2,316 meters (3000 to 7600 feet). The dominant slopes have gradients of

20 to 60 percent. This unit is slightly to moderately dissected by streams

with the dominant stream pattern being deranged. Wetlands and small ponds are

a major component of this unit.

LTA Components: This landtype association consists of surficial landslides

and bedrock landslides.

Surficial landslide deposits are formed in glacial till and colluvium parent

materials. Slope gradients range from 20 to 50 percent. Soils on these

landforms are moderately deep to deep and moderately developed with gravelly

medium textures. These soils are classified as Typic and Andeptic Cryoboralfs

and Typic Eutroboralfs. Rock outcrop occurs on less than 10 percent of this

landscape component. The dominant potential natural vegetation includes

subalpine fir and western red cedar series. This component represents 60

percent of this unit.

Bedrock landslide landforms are formed in residual and colluvial parent

materials derived from native bedrock formations. Slope gradients range from

30 to 50 percent. Soils on these landforms are shallow to deep and moderately

developed with gravelly medium and moderately fine textures. These soils are

classified as Typic and Andeptic Cryoboralfs, Typic Eutroboralfs, and Andic

Cryochrept. Rock outcrop occurs on about 15 percent of this landscape

component. The dominant potential natural vegetation includes subalpine fir,

Douglas-fir, and western red cedar series. This component represents 40

percent of this unit.

Compiled by: Dean Sirucek, Flathead National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 379
CHAPTER 13

LTA Descriptions

Section M333C Northern Rockies

This Section occurs in northwest Montana. It generally coincides with the

Alpine Glaciated Metasedimentary Mountains geomorphic area previously

described. Nineteen LTAs were mapped in this Section. See Appendix F for a

complete list of LTAs and their acreage. Map unit descriptions are preceded by

the following illustrations:

 Figure 55: Map showing location of M333C within the Northern Region

 Figure 56: M333C landscape photograph, Mission Range and Mission Valley

 Flathead National Forest

 Figure 57: Map showing distribution of LTAS within M333C

 Figure 58: Bar chart showing abundance of landform groups within M333C

Figure 59: Bar chart showing abundance of geologic material groups

within M333C

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 380
LTA10-M333C

LTA10-M333B

LTA10-M333D

VALLEYS: RECENT COARSE ALLUVIUM

Location: This LTA is located in the inter-mountain valleys of the Flathead,

Clark Fork, and Kootenai River basins of northwest Montana.

 Acreage by Section

 10-M333C 63,658

 10-M333B 191,377

 10-M333D 160,219

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a valley bottom

landscape setting, which is composed of stream terraces, floodplains, and

alluvial basins. Parent materials are unstratified to stratified deposits of

sands, silts, and/or gravels underlain primarily by Proterozoic metasediments,

Cenozoic siltstones, and/or glacial deposits.

Accessory Characteristics: The primary soils are deep with extremely gravelly

coarse to medium textures. The vegetation is a mosaic of deciduous forest,

coniferous forest, and wet meadow/shrubland. Mean annual precipitation ranges

from 36 to 152 centimeters (14 to 60 inches). The elevation range is 758 to

1,970 meters (2500 to 6500 feet). The dominant slopes have gradients of 3 to

15 percent. This LTA is moderately dissected by streams with the dominant

stream pattern being dendritic. Wetlands and river over-flow channels are a

major component of this LTA.

LTA Components: This landtype association consists of stream terraces,

floodplains, and alluvial basins.

Stream terraces are formed in coarse, stratified alluvium. These terraces have

slope gradients that range from 0 to 15 percent. Soils on these landforms are

deep, poorly developed, and mostly of sand and gravel. The soils vary from

moderately well drained to well drained. The major soils on the moderately

well-drained sites are Oxyaquic Udifluvents, Typic Ustifluvents, and Typic

Udifluvents on the well drained sites. The major soils on the well drained

sites are Dystric Eutrochrepts, Andic Dystrochrepts, and Typic Xerochrepts.

Rock outcrops occur less than 2 percent of the time. The dominant potential

natural vegetation series are black cottonwood, Engelmann spruce, western

redcedar, grand fir, and Douglas-fir. This component represents 60 percent of

the LTA.

Floodplains and alluvial basins are formed in coarse stratified or

unstratified alluvium. These areas have slope gradients that range from 0 to

10 percent. Soils on these landforms are deep, weakly developed and consist

mostly of sand, gravel, and silt. These soils vary from moderately well

drained to poorly drained. The major soils are classified as Typic

Endoaquents, or Typic and Aeric Endoaquepts. Rock outcrops occur less than 1

percent of the time. The dominant potential natural vegetation series are

subalpine fir, Engelmann spruce and Drummond's willow. This component

represents 40 percent of the LTA.

Compiled by: Dean Sirucek, Flathead National Forest; Skip Barndt, Lolo

National Forest; Louis Kuennen, Kootenai National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 381
LTA11-M333C

LTA11-M333B

LTA11-M333D

VALLEYS: LACUSTRINE SEDIMENTS

Location: This unit is located in the inter-mountain valleys of the Clark

Fork, Flathead, and Kootenai River basins of northwest Montana.

 Acreage by Section

 11-M333C 11,821

 11-M333B 533,326

 11-M333D 111,455

LTA Setting and General Characteristics

Differentiating Characteristics: This unit occurs in a valley bottom landscape

setting, which is typically composed of glacial lacustrine deposits that have

level to slightly undulating topography. Parent materials consist of

stratified lake sediments of very fine sands, silts, and clays.

Accessory Characteristics: The primary soils are deep with medium to

moderately fine textures. The vegetation ranges from a continuous cover of

coniferous vegetation on the well drained sites to wet meadow/shrubland on the

poorly drained sites. Mean annual precipitation ranges from 36 to 152

centimeters (14 to 60 inches). The elevation range is 758 to 1,818 meters

(2500 to 6000 feet). The dominant slopes have gradients of 2 to 20 percent. 

This map unit is slightly dissected by streams. Where present, the dominant

stream pattern is dendritic. Wetlands and ponds are a major component of the

unit.

LTA Components: This landtype association consists of lacustrine terraces and

lacustrine basins.

Lacustrine terraces and lacustrine basins are formed in stratified lake

sediments. These landforms have dominant slope gradients ranging from 0 to 25

percent. Included with these landforms are terrace risers/scarps that have

slopes that range from 40 to 70 percent. Soils on these landforms are deep,

weak to moderately developed with medium and moderately fine textures. In

northwestern Montana the major soils on the forested, well-drained sites are

classified as Glossic Cryoboralfs, Typic Eutroboralfs, and Eutric

Glossoboralfs fine, mixed, frigid. In Section M333B additional major soils are

Andic and Typic Dystrochrepts. The lower elevation, non-forested valleys the

soils are classified as Typic Natrixeralfs and Typic Xerochrepts. The dominant

vegetation is western redcedar, subalpine fir, grand fir and Douglas-fir.

The major soils on the poorly drained sites are classified as Aeric Epiaquepts

and Aquic Eutroboralfs with inclusions of Typic Borosaprists. Rock outcrop

occurs on less than 2 percent of this landscape component. The dominant

potential natural vegetation series on the poorly drained sites are Engelmann

spruce, Drummond's willow and beaked sedge.

Compiled by: Dean Sirucek, Flathead National Forest; Skip Barndt, Lolo

National Forest; Louis Kuennen, Kootenai National Forest.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 382
LTA12-M333C

LTA12-M333B

LTA12-M333D

VALLEYS: OUTWASH AND OTHER OLDER COARSE ALLUVIAL DEPOSITS

Location: This map unit is located in the inter-mountain valleys of the Clark

Fork, Flathead, and Kootenai River basins of northwest Montana.

 Acreage by Section

 12-M333C 97,651

 12-M333B 428,208

 12-M333D 181,889

LTA Setting and General Characteristics

Differentiating Characteristics: This unit occurs in valley bottom landscape

settings, which are typically composed of glacial outwash plains or outwash

terraces that have undulating surfaces. Steep escarpments form the front of

the some of the terraces. Parent materials consist of either stratified or

unstratified glacial fluvial deposits of sand and gravel material. These

deposits are typically underlain by glacial moraine deposits or Proterozoic

metasedimentary bedrock.

Accessory Characteristics: The primary soils are deep with extremely gravelly

coarse textures. These soils are typically excessively well drained with

inclusions of poorly drained soils. The vegetation is primarily coniferous

forest with areas of wet meadow/shrubland. Mean annual precipitation ranges

from 36 to 140 centimeters (14 to 55 inches). The elevation range is 758 to

1,667 meters (2500 to 5500 feet). The dominant slopes have gradients of 2 to

20 percent. This map unit is moderate to highly dissected by streams or

rivers with the dominant stream pattern being dendritic. Wetlands and riparian

areas are important components of this unit.

LTA Components: This landtype association consists of glacial outwash plains

and outwash terraces.

These glacial outwash plains and outwash terraces are formed in coarse,

stratified or unstratified glacial fluvial sediments. Slope gradients range

from 0 to 25 percent with gradients up to 50 percent on the terrace risers.

Soils on these landforms are deep, weakly developed with extremely gravelly

coarse textures. The major soils are classified as Dystric Eutrochrepts, 

Typic Dystrochrept, Andic Dystrochrepts, and Andic Ustochrepts. Rock outcrop

occurs on less than 5 percent of this map unit. The dominant potential natural

vegetation is Douglas-fir, western redcedar, subalpine fir and spruce.

Compiled by: Dean Sirucek, Flathead National Forest; Skip Barndt, Lolo

National Forest; Louis Kuennen. Kootenai National Forest.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 383
LTA14-M333C

LTA14-M333B

VALLEYS: RECENT FINE ALLUVIUM

Location: This LTA is located in the inter-mountain valleys of the Flathead

River basin in northwest Montana.

 Acreage by Section

 14-M333C 5,120

 14-M333B 33,343

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a valley bottom

landscape setting, which is composed of stream terraces, floodplains, and

alluvial basins. Parent materials are stratified deposits of fine sands,

silts, and clays with or without gravels. These deposits are underlain

primarily by Cenozoic siltstones and glacial deposits.

Accessory Characteristics: The primary soils are deep with medium or

moderately fine textures. The vegetation is a mosaic of deciduous forest,

coniferous savannah, grassland, and wet meadow/shrubland. Mean annual

precipitation ranges from 30 to 51 centimeters (12 to 20 inches). The

elevation range of this LTA is 745 to 1,067 (2460 to 3500 feet). The dominant

slopes have gradients of 0 to 10 percent. This LTA is moderately dissected by

streams with the dominant stream pattern being dendritic. Wetlands and river

over-flow channels are a major component of this LTA.

LTA Components: This landtype association consists of stream terraces,

floodplains, and alluvial basins.

Stream terraces are formed in stratified alluvium. These terraces have slope

gradients that range from 0 to 10 percent. Soils on these landforms are deep,

poorly developed, and coarse to moderately-fine textured. These soils are

classified as Typic Ustifluvents, Udic Haploborolls, and Typic Eutrochrepts.

Rock outcrops occur less than 1 percent of the time. The dominant potential

natural vegetation series include ponderosa pine and rough fescue. This

component represents 85 percent of the LTA.

Floodplains and alluvial basins are formed in stratified recent alluvium.

These areas have slope gradients that range from 0 to 10 percent. Soils on

these landforms are deep, weakly developed with medium to moderately-fine

textures. The major soils are classified as Fluvaqentic Haploxerolls, or Typic

and Aeric Endoaquepts. Rock outcrops occur less than 1 percent of the time.

The dominant potential natural vegetation series include ponderosa pine,

Engelmann spruce, and Geyer willow. This component represents 15 percent of

the LTA.

Compiled by: Dean Sirucek, Flathead National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 384
LTA20-M333C

LTA20-M333B

LTA20-M333D

BREAKS: METASEDIMENTARY (BELT)

Location: This unit is located in the Whitefish, Swan, Mission, Bitterroot,

Purcell, Salish, Cabinet, and Flathead mountain ranges of the Clark Fork,

Flathead, and Kootenai River basins in northwest Montana.

 Acreage by Section

 20-M333C 163,793

 20-M333B 212,411

 20-M333D 1,000,850

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in both the upland and

alpine landscape settings, which is typically composed of structural breakland

and stream breakland landforms. Parent materials are volcanic ash overlying

weakly-weathered, moderately metamorphosed, Proterozoic metasedimentary

bedrock composed of argillites, siltites, quartzites, limestones and

dolomites.

Accessory Characteristics: The primary soils are shallow to moderately deep

with very gravelly medium textures. The vegetation is a mosaic of coniferous

forest, and mountain shrub/grass lands. Mean annual precipitation ranges from

41 to 229 centimeters (16 to 90 inches). The elevation range is 697 to 2,590

meters (2300 to 8500 feet). The dominant slopes have gradients of 55 to 70

percent. This unit is slightly to moderately dissected by streams with the

dominant stream patterns being sub-parallel and parallel. Major streams or

rivers are typically located at the base of stream breaks. Lakes and ponds are

a minor component of this unit.

LTA Components: This landtype association consists of structural and stream

breaks.

Structural breaks are formed in colluvial materials from weakly weathered

metasedimentary bedrock. Slope gradients range from 50 to 100 percent. Soils

on these landforms are shallow to moderately deep, weakly developed, with very

gravelly medium textures. These soils are classified as Lithic, Typic and

Andic Dystrochrepts on warm sites; and Lithic, Typic, and Andic Cryochrepts on

colder sites. Rock outcrop and talus occur on 20 to 80 percent of this

landscape component. The dominant potential natural vegetation on the warmer

sites are Douglas-fir; and on the cooler sites are subalpine fir, and

whitebark pine-subalpine fir. This component represents 80 percent of this

unit.

Stream breaks are formed in colluvial materials from weakly weathered

metasedimentary bedrock. Slope gradients range from 50 to 90 percent. Soils on

these landforms are shallow to moderately deep and weakly developed with very

gravelly medium textures. These soils are classified as Lithic and Typic

Dystrochrepts on the warmer sites; and Lithic, Typic and Andic Cryochrepts on

the cooler sites. Rock outcrop and talus occur on 20 to 60 percent of this

landscape component. The dominant potential natural vegetation on the warmer

sites is Douglas-fir; and on the cooler sites subalpine fir. This component

represents 20 percent of this unit.

Compiled by: Dean Sirucek, Flathead National Forest; Skip Barndt, Lolo

National Forest; Louis Kuennen, Kootenai National Forest.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 385
LTA25-M333C

BREAKS: SANDSTONES, SHALES AND LIMESTONES

Location: This unit is located in the Whitefish, Swan, and Flathead mountain

ranges of the Flathead River basin in northwest Montana.

 Acreage by Section

 25-M333C 10,321

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in both upland and

alpine landscape settings, which are typically composed of structural breaks

and stream breaks. Parent materials are volcanic ash overlying weakly

weathered Paleozoic and Mesozoic sandstone, shale, and limestone bedrock.

Accessory Characteristics: The primary soils are shallow to moderately deep,

with very gravelly medium and moderately fine textures. The vegetation is a

mosaic of coniferous forest, shrubland and mountain grasslands. Mean annual

precipitation ranges from 51 to 152 centimeters (20 to 60 inches). The

elevation range is 915 to 2,134 meters (3000 to 7000 feet). The dominant

slopes have gradients of 55 to 70 percent. This unit is slightly to moderately

dissected by streams, with the dominant stream patterns being sub-parallel and

parallel. Major streams or rivers are typically located at the base of the

stream breaks. Lakes and ponds are a minor component of this unit.

LTA Components: This landtype association consists of structural and stream

breaks.

Structural breaks are formed in colluvial materials from weakly weathered

sandstone, shale, and limestone, with a surface layer of volcanic ash. Slope

gradients range from 50 to 100 percent. Soils on these landforms are shallow

to moderately deep, weakly developed, with gravelly medium and moderately-fine

textures. These soils are classified as Lithic, Typic and Andic Cryochrepts.

Rock outcrop occurs on between 20 to 80 percent of this landscape component.

The dominant potential natural vegetation at lower elevations is Douglas-fir;

and at higher elevations subalpine fir, and whitebark pine-subalpine fir. 

This component represents 80 percent of this unit.

Stream breaks are formed in colluvial materials from weakly weathered

sandstone, shale, and limestone. Slope gradients range from 50 to 90 percent.

Soils on these landforms are shallow to moderately deep, weakly developed,

with very gravelly medium textures. These soils are classified asLithic,

Typic and Andic Cryorthents. Rock outcrop occurs on 20 percent of this

landscape component. The dominant potential natural vegetation at lower

elevations is Douglas-fir with subalpine fir at the higher elevations. This

component represents 20 percent of this unit.

Compiled by: Dean Sirucek, Flathead National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 386
LTA27-M333C

LTA27-M332C

LTA27-331D

BREAKS: CARBONATES

Location: This LTA is located mostly in the Rocky Mountain Front in northwest

Montana on the Lewis and Clark National Forest.

 Acreage by Section

 27-M333C 461

 27-M332C 97,585

 27-331D 148

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of structural breaks. Parent materials

are residuum underlain by limestone bedrock.

Accessory Characteristics: The primary soils are shallow and moderately deep

with loamy skeletal textures. The vegetation is a mosaic of coniferous forest

and rock. Mean annual precipitation ranges from 51 to 54 centimeters (20 to 25

inches). The elevation range of this LTA is 1968 to 2460 meters (6000 to 7500

feet). The dominant slopes have gradients of 60 to 80 percent. This LTA is

moderately to highly dissected by streams, with the dominant stream pattern

being subparallel. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of structural breaks.

Structural breaks are formed by thrust faulting along the eastern edge of the

overthrust belt, and are most dramatic in limestone bedrock. Slope gradients

range from 60 to 80 percent. Soils on these landforms are shallow to

moderately deep, weakly developed, overlie calcareous, very stoney colluvium,

and have loamy skeletal textures. These soils are classified as Lithic and

Typic Ustochrepts and Typic Cryochrepts. Rock outcrop occurs on 15 to 50

percent of this landscape component. The dominant potential natural vegetation

is subalpine fir. This component represents 100 percent of this LTA.

Compiled by: Robin Strathy, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 387
LTA40-M333C

LTA40-M333B

LTA40-M333D

STEEP GLACIATED MOUNTAIN SLOPES: METASEDIMENTARY (BELT)

Location: This map unit is located in the Bitterroot, Cabinet, Purcell,

Salish, Swan, Mission, Flathead, and Whitefish Mountain ranges of the Clark

Fork, Flathead and Kootenai basins in northwest Montana.

 Acreage by Section

 40-M333C 1,637,034

 40-M333B 221,169

 40-M333D 222,209

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in an upland and alpine

landscape settings, which are primarily composed of glacial troughwall, cirque

headwall, and cirque basin landforms. Parent materials are alpine glacial

debris and colluvium derived from and underlain by moderately metamorphosed

Proterozoic metasediments composed of argillite, siltite, quartzite,

limestone, and dolomite bedrocks. Inclusions of other bedrocks such as granite

occur in this map unit.

Accessory Characteristics: The primary soils are shallow to moderately deep,

with cobbly or gravelly medium textures. The vegetation is a mosaic of

coniferous forest, alpine meadows, and shrubland associated with avalanche

chutes. Mean annual precipitation ranges from 102 to 305 centimeters (40 to

120 inches). The elevation range of this unit is 1,212 to 3,182 meters (4000

to 10,500 feet). The dominant slopes range from 50 to 90 percent. The cirque

basin portion of the map unit has slopes that range from 5 to 40 percent. The

troughwall landforms are moderately to highly dissected by streams with the

dominant stream pattern being parallel. The cirque headwall and cirque basin

landforms are weakly dissected by streams with the dominant stream pattern

being parallel. Wetlands are associated with the cirque basins, and occur as a

minor component of this unit.

LTA Components: This landtype association consists of glacial troughwalls,

cirque headwalls, and cirque basins.

Glacial troughwalls are formed in glacial tills on the lower elevation slopes

with volcanic ash influenced colluvium on the higher elevation slopes. Slope

gradients range from 50 to 90 percent. Soils on the lower slopes of this

landform are moderately shallow to deep and are moderate to highly developed,

with cobbly medium textures. The major soils on the lower slopes are

classified as Andeptic and Typic Cryoboralfs. Soils on the upper slopes of

this landform are shallow to moderately deep, are moderately developed, and

have gravelly medium textures. The major soils on the higher slopes are Andic,

Typic, and Lithic Cryochrepts. Rock outcrops occupy up to 15 percent of the

area. The dominant potential natural vegetation series are grand fir, western

redcedar, Douglas-fir and subalpine fir on the lower slopes; and subalpine fir

and mountain hemlock on the upper slopes. This component represents 55 percent

of the LTA.

Cirque headwalls/cirque basins are formed in glacial till on the lower

elevation slopes and volcanic ash influenced colluvium on the higher elevation

slopes. Included in this alpine landscape setting are small areas of alpine

ridge landforms. Slope gradients range from 5 to 90 percent. Soils on these

landforms are shallow to moderately deep, and weakly developed with very

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 388
gravelly medium textures. The major soils are classified as Lithic Cryochrepts

and Andic Cryochrepts. Rock outcrops occupy more than 40 percent of the area.

The dominant potential natural vegetation is subalpine fir, and whitebark

pine-subalpine fir. This component represents 45 percent of the LTA.

Compiled by: Dean Sirucek, Flathead National Forest; Louis Kuennen, Kootenai

National Forest; Skip Barndt, Lolo National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 389
LTA43-M333C

LTA43-M332D

LTA43-M332C

LTA43-331D

STEEP GLACIATED MOUNTAIN SLOPES: CARBONATES

Location: This LTA is located mostly on the Rocky Mountain Front in the Lewis

and Clark National Forest.

 Acreage by Section

 43-M333C 233

 43-M332D 12,878

 43-M332C 158,098

 43-331D 624

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occupies high elevation landscapes

where alpine glaciation has occurred. It is typically occupied by fault

escarpments (mostly in M332C), cirques, troughwalls, and ridges. The parent

material is limestone.

Accessory Characteristics: The primary soils are Lithic Cryorthents and

Cryochrepts. The vegetation is coniferous forest. Mean annual precipitation

ranges from 76 to 127 centimeters (30 to 50 inches). The elevation range of

this LTA is 1524 to 2438 meters (5000 to 8000 feet). The dominant slope

gradients are 70 to 90 percent. This LTA is moderately dissected by streams

and the dominant drainage pattern is dendritic. Wetlands, lakes, and ponds are

a minor component of this LTA.

LTA Components: This landtype association consists of steep west facing

slopes, very steep glacial breaks, and rockland/scree on fault escarpments.

The steep west facing slopes are formed in limestone. These slopes have

gradient ranging from 40 to 60 percent. Soils on these landscapes are shallow,

poorly developed, and consist mainly of loam and flaggy gravel. These soils

are classified as Lithic Cryorthents. Rock outcrop occurs on less than 15

percent of this landscape component. The dominant potential vegetation is open

growing wind deformed Douglas-fir, limber pine, and spruce on scree. This

component represents 30 percent of this LTA.

The very steep glacial breaks are formed in limestone. Slope gradients are

mainly greater than 60 percent. The soil on this landscape is deep, poorly

developed, and consist mainly of sandy-loam and gravel. These soils are

classified as Typic Cryochrepts. Rock outcrop and talus occur on seventy-five

percent of this landscape component. The dominant potential vegetation is

Douglas-fir series. This component represents 30 percent of this LTA.

The rockland/scree component of this LTA occurs on fault escarpments in

limestone. Slopes are mainly greater than 60 percent. Soil on this landscape

consists of sandy loam, loamy sand, gravel, and cobble. These materials are

classified as scree. The dominant potential vegetation is subalpine fir, and

whitebark pine-subalpine fir series. This component represents 40 percent of

this LTA.

Compiled by: Richard Saunders and Robin Strathy, Lewis and Clark National

Forest.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 390
LTA44-M333C

STEEP GLACIATED MOUNTAIN SLOPES: SANDSTONES, SHALES AND CARBONATES

Location: This map unit is located in the Swan, Flathead, and Whitefish

mountain ranges of the Flathead River basin in northwest Montana.

 Acreage by Section

 44-M333C 218,230

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in upland and alpine

landscape settings, which are primarily composed of glacial troughwall, cirque

headwall and cirque basin landforms. Parent materials are alpine glacial

debris and frost shattered colluvium derived from and underlain by Paleozoic

and Mesozoic sandstone, shale, and limestone bedrocks.

Accessory Characteristics: The primary soils are shallow to moderately deep,

with gravelly medium to moderately-fine textures. The vegetation is a mosaic

of coniferous forest, alpine meadows, and shrubland associated with avalanche

chutes. Mean annual precipitation ranges from 76 to 229 centimeters (30 to 90

inches). The elevation range is 1,033 to 2,590 meters (3500 to 8500 feet). The

dominant slopes range from 50 to 90 percent. The cirque basin portion of the

map unit has slopes that range from 5 to 40 percent. This LTA is moderately to

highly dissected by streams, with the dominant stream pattern being parallel.

Wetlands are associated with the cirque basins, and occur as a minor component

of this unit.

LTA Components: This landtype association consists primarily of glacial

troughwalls, cirque headwalls, and cirque basins.

Glacial troughwalls are formed in glacial tills on the lower elevation slopes,

and volcanic ash influenced colluvium on the higher elevation slopes. Slope

gradients range from 50 to 90 percent. Soils on the lower slopes of this

landform are moderately deep to deep, are moderate to highly developed, and

have gravelly medium to moderately-fine textures. The major soils on the lower

slopes are classified as Andeptic and Typic Cryoboralfs, clayey or

loamy-skeletal, mixed. Soils on the upper slopes of this landform are shallow

to moderately deep, are moderately developed and have gravelly medium

textures. The major soils on the higher slopes are Andic, Typic, and Lithic

Cryochrepts. Rock outcrops occupy up to 15 percent of the area. The dominant

potential natural vegetation is Douglas-fir and subalpine fir on the lower

slopes; and subalpine fir on the upper slopes. This component represents 55

percent of the LTA.

Cirque headwalls/cirque basins are formed in glacial till on the lower slopes

and volcanic ash influenced colluvium on the higher slopes. Included in this

alpine landscape setting are small areas of alpine ridge landforms. Slope

gradients range from 5 to 90 percent. Soils on these landforms are shallow to

moderately deep, weakly developed, with gravelly medium to moderately-fine

textures. The major soils are classified as Lithic Cryochrepts and Andic

Cryochrepts. Rock outcrops occupy more than 50 percent of the area. The

dominant potential natural vegetation is subalpine fir, and whitebark

pine-subalpine fir. This component represents 40 percent of the LTA. Included

in this map unit in the South and Middle Forks of the Flathead River are areas

of moderately glaciated structural breaks. This inclusion represents up to 5

percent of the map unit.

Compiled by: Dean Sirucek, Flathead National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 391
LTA50-M333C

GLACIATED MOUNTAIN SLOPES: METASEDIMENTARY (BELT)

Location: This map unit is located primarily in the Swan, Salish, Mission,

Whitefish, and Flathead mountain ranges of the Flathead and Swan River basins,

in northwest Montana.

 Acreage by Section

 50-M333C 687,672

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in both valley bottom

and upland landscape setting, which is primarily composed of glacial moraine

landforms. Parent materials are continental or alpine glacial debris with or

without volcanic ash surface layers; underlain by Proterozoic metasedimentary

bedrock, composed of argillites, siltites, limestones, and quartzites.

Accessory Characteristics: The primary soils are moderately deep to very

deep, with very gravelly moderately coarse and medium textures. The major

vegetative cover is a dense coniferous forest with occasional meadow openings.

Mean annual precipitation ranges from 36 to 203 centimeters (14 to 80 inches).

The elevation range is 853 to 2,286 meters (2800 to 7500 feet). The dominant

slopes range from 20 to 50 percent. This map unit is moderately to highly

dissected by streams, with the dominant stream pattern being dendritic.

Wetlands are a minor component of this map unit.

LTA Components: This landtype association consists of glacial moraines with

glacially scoured ridge tops as a minor component.

On the valley bottom landscape setting the glacial moraines occur on rolling

hummocky topography, with slopes that range from 5 to 30 percent slope. On the

upland landscape setting the glacial moraines occur on straight to slightly

concave slopes, with range from 20 to 55 percent in gradient. These glacial

moraines typically occur as the toe-slope associated with glacial troughwalls.

Soils on these landforms are moderately deep to very deep, and are moderate to

highly developed, with gravelly medium textures. The major soils are

classified as Andeptic Cryoboralfs, Typic Eutroboralfs, and Dystric

Cryochrepts. Rock outcrops occupy less than 15 percent of the area. The

dominant potential natural vegetation is Douglas-fir, grand fir, and subalpine

fir. This component represents 85 percent of this map unit.

Glacially scoured ridge tops are formed in residual soil materials. Slope

gradients range from 5 to 20 percent. Soils on these landforms are shallow to

moderately deep, moderately developed, with gravelly medium textures. The

major soils are classified as Andic Cryochrepts. Rock outcrops occupy less

than 15 percent of the area. The dominant potential natural vegetation is

subalpine fir and Douglas-fir. This component represents 15 percent of this

map unit.

Compiled by: Dean Sirucek, Flathead National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 392
LTA53-M333C

LTA53-M333B

LTA53-M332B

GLACIATED MOUNTAIN SLOPES: SANDSTONES, SHALES, AND CARBONATES

Location: This map unit is located in of the Swan, Mission, Flathead, and

Whitefish mountain ranges of the Flathead, Clearwater, and Blackfoot River

basins in northwest Montana.

 Acreage by Section

 53-M333C 100,613

 53-M333B 8,091

 53-M332B 6,924

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in both valley bottom

and upland landscape settings, which are primarily composed of glacial moraine

landforms. Parent materials are continental or alpine glacial debris with or

without volcanic ash surface layers; underlain by Paleozoic and Mesozoic

sandstone, shale, and limestone bedrocks. In the North Fork of the Flathead

River areas of Tertiary siltstone are included in this map unit.

Accessory Characteristics: The primary soils are moderately deep to very

deep, with gravelly medium and moderately fine textures. The major vegetative

cover is a dense coniferous forest with occasional meadow openings. Mean

annual precipitation ranges from 51 to 178 centimeters (20 to 70 inches). The

elevation range is 1,036 to 2,316 meters (3400 to 7600 feet). The dominant

slopes range from 5 to 50 percent. This map unit is moderately to highly

dissected by streams, with the dominant stream pattern being dendritic.

Wetlands are a minor component of this unit.

LTA Components: This landtype association consists of glacial moraines with

glacially scoured ridge tops as a minor component.

On the valley bottom landscape setting the glacial moraines occur on rolling

hummocky topography, with slopes that range from 5 to 30 percent slope. On the

upland landscape setting the glacial moraines occur on straight to slightly

concave slopes, with range from 20 to 55 percent in gradient. These glacial

moraines typically occur as the toe-slope associated with glacial troughwalls.

Soils on these landforms are moderately deep to very deep, and are moderate to

highly developed, with gravelly moderately-fine or fine textures. The major

soils are classified as Typic Eutrochrepts and Andeptic Cryoboralfs. Rock

outcrops occupy less than 15 percent of the area. The dominant potential

natural vegetation is Douglas-fir and subalpine fir.

A minor component of this map unit is glacially scoured ridge tops. Slope

gradients range from 5 to 20 percent. Soils on these landforms are shallow to

moderately deep, moderately developed, with gravelly medium textures. The

major soils are classified as Andic Cryochrepts. Rock outcrops occupy less

than 15 percent of the area. The dominant potential natural vegetation is

subalpine fir and Douglas-fir. This component represents 15 percent of this

map unit.

Compiled by: Dean Sirucek, Flathead National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 393
LTA58-M333C

LTA58-M333B

GLACIATED MOUNTAIN SLOPES: HIGHLY WEATHERED BELT TILL

Location: This map unit is located in the Whitefish, Mission, Swan, Purcell,

Salish, Cabinet, and Flathead mountain ranges of the Flathead, Kootenai, and

Swan River basins in northwest Montana.

 Acreage by Section

 58-M333C 20,031

 58-M333B 164,491

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in both upland and valley

bottom landscape settings, which are typically composed of glacial moraine

landforms. Parent materials are alpine or continental glacial debris deposited

during Pre-Wisconsin glacial periods. These deposits are underlain by

moderately metamorphosed, Proterozoic metasedimentary bedrock composed of

argillites, siltites, dolomites, limestones, and quartzites; or Tertiary

siltstones.

Accessory Characteristics: The primary soils are moderately deep to very deep

very gravelly coarse silt/fine sandy loams. The major vegetative cover is a

dense coniferous forest with occasional grassy openings. Mean annual

precipitation ranges from 51 to 152 centimeters (20 to 60 inches). The

elevation range is 667 to 1,707 meters (2200 to 5600 feet). The dominant

slopes range from 20 to 50 percent. This map unit is moderately to highly

dissected by streams with the dominant stream pattern being dendritic.

Wetlands are a minor component of this map unit. 

LTA Components: This landtype association consists primarily of glacial

moraines.

The landscape setting for this map unit varies from a valley bottom to a

moderately steep upland setting. In the valley bottom landscape settings, the

glacial moraines occur on rolling, hummocky topography, with slopes that range

from 5 to 30 percent slope. In the upland landscape setting the glacial

moraines occur on straight to slightly concave slopes that range from 20 to 55

percent in gradient. These glacial moraines typically occur as the toe-slope

associated with glacial troughwalls.

Soils on these landforms are moderately deep to very deep and are moderate to

highly developed with gravelly moderately-fine or fine textures. The major

soils are classified as Typic Glossoboralfs, Typic Eutroboralfs, and Andeptic

Cryoboralfs. Rock outcrops occupy less than 5 percent of the area. The

dominant potential natural vegetation is western redcedar, grand fir,

subalpine fir, and Douglas-fir.

Compiled by: Dean Sirucek, Flathead National Forest and Louis Kuennen,

Kootenai National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 394
LTA60-M333C

LTA60-M333B

MOUNTAIN SLOPES AND RIDGES: METASEDIMENTARY (BELT)

Location: This unit is located in the Whitefish, Swan, Purcell, Cabinet,

Salish, Mission, and Flathead Mountain Ranges of the Flathead, Kootenai, and

Swan River basin in northwest Montana.

 Acreage by Section

 60-M333C 114,155

 60-M333B 497,972

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in both the upland and

alpine landscape settings, which are typically composed of dissected mountain

slope, glaciated mountain slope, and glacially scoured ridge top landforms.

The geomorphic processes that occur on these areas include: colluvial, fluvial

and glacial, erosion or deposition. Parent materials are volcanic ash

overlying weakly weathered, moderately metamorphosed Proterozoic

metasedimentary bedrock composed of argillites, siltites, quartzites, and

limestones.

Accessory Characteristics: The primary soils are shallow to moderately deep

with very gravelly medium textures. The vegetation is a mosaic of coniferous

forest, mountain shrublands, and mountain grasslands. Mean annual

precipitation ranges from 46 to 203 centimeters (18 to 80 inches). The

elevation range is 758 to 2,286 meters (2500 to 7500 feet). The dominant

slopes have gradients of 15 to 50 percent. This unit is moderate to strongly

dissected by streams with the dominant stream patterns being dendritic and

sub-parallel.

LTA Components: This landtype association consists of glacially scoured ridge

tops and dissected mountain slopes (fluvial) with inclusions of glaciated

mountain slopes.

Glacially scoured ridge tops have been strongly modified by continental ice.

The prominent features are ridge tops and ridge noses with exposed bedrock.

These areas have slopes that range from 10 to 45 percent. Soils on these

landforms are shallow to moderately deep and weak to moderately developed with

medium textures. The major soils are classified as Lithic, Andic, or Typic

Cryochrepts, and Typic and Lithic Dystrochrepts. Rock outcrops occupy more

than 50 percent of the area. The dominant potential natural vegetation is

subalpine fir-whitebark pine, subalpine fir and Douglas-fir. This landform

component makes up 50 percent of the LTA.

The dissected mountain slopes (fluvial) landscape is one that is weathering in

place. It is chemical weathering further affected by colluvial action. Slope

gradients range from 30 to 60 percent. Soils on these landforms are moderately

deep to deep, weak to moderate development, with medium textures. The major

soils are classified as Andic Cryochrepts, Andeptic and Typic Cryoboralfs,

and Typic or Argic Cryoborolls, Typic Haploborolls, and Typic Dystrochrept. 

Rock outcrops occupy less than 10 percent of the area. The dominant potential

natural vegetation series are Douglas-fir and subalpine fir. This landform

component represents 50 percent of the LTA.

Compiled by: Dean Sirucek, Flathead National Forest; Louis Kuennen, Kootenai

National Forest.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 395
LTA66-M333C

LTA66-M332C

MOUNTAIN SLOPES AND RIDGES: CARBONATES

Location: This LTA is located primarily in the middle and southern part of the

Rocky Mountain front in Northwest Montana.

 Acreage by Section

 66-M333C 164

 66-M332C 37,295

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs on ridgetops, plateaus, steep

valley slopes, and benchy lower valley slopes. Parent materials are Paleozoic

limestones.

Accessory Characteristics: The primary soils are moderately deep, skeletal

loams, silt loams, and clay loams. The vegetation is a coniferous forest.

Mean annual precipitation ranges from 50 to 127 centimeters (20 to 50 inches).

The elevation range of this LTA ranges from 1524 to 2896 meters (5000 to 9500

feet). The dominant slopes have gradients of 10 to greater than 60 percent.

LTA Components: This landtype association consists of ridge tops and steep

valley sideslopes which are typically formed on limestone.

Ridge tops typically have slopes of 10 to 25 percent. Soils on these landforms

are moderately deep, weakly developed, and consist mainly of loamy- skeletal

silt loams, loams, and clay loams. The major soils are classified as Perelgic

and Typic Cryoborolls. The major potential natural vegetation is rough fescue.

Rock outcrop occurs on less than 15 percent of this LTA. This component

represents 30 percent of this LTA.

Steep valley sideslopes are on slopes of 25 to 60 percent. Soils on these

landforms are moderately deep, moderately well developed, Andic Cryochrepts in

the loamy skeletal families. The major potential natural vegetation is

subalpine fir. Rock outcrop occurs on less than 15 percent of this LTA. This

component represents 70 percent of this LTA.

Compiled by: Robin Strathy, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 396
LTA68-M333C

LTA68-M333B

LTA68-M333D

MOUNTAIN SLOPES AND RIDGES: SANDSTONES, SHALES, AND CARBONATES

Location: This unit is located in the Whitefish, Swan, and Flathead mountain

ranges of the Flathead, Clearwater, and Blackfoot River basins in northwest

Montana.

 Acreage by Section

 68-M333C 36,067

 68-M333B 8,043

 68-M333D 1,511

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in both upland and

alpine landscape settings, which are typically composed of dissected mountain

slopes, glaciated mountain slopes, and glacially scoured ridge top landforms.

Colluvial, fluvial and glacial, erosional/depositional geomorphic processes

occur in these areas. Parent materials are volcanic ash overlying weakly

weathered Paleozoic and Mesozoic sandstone, shale, and limestone bedrock.

Accessory Characteristics: The primary soils are shallow to moderately deep

with very gravelly medium and moderately fine textures. The vegetation is a

mosaic of coniferous forest, mountain shrubland, and mountain grassland. Mean

annual precipitation ranges from 51 to 177 centimeters (20 to 70 inches). The

elevation range is 1,219 to 2,134 meters (4000 to 7000 feet). The dominant

slopes have gradients of 55 to 70 percent. This unit is moderate to strongly

dissected by streams with the dominant stream patterns being dendritic and

sub-parallel.

LTA Components: This landtype association consists of glacially scoured ridge

tops and dissected mountain slopes (fluvial) with inclusions of glaciated

mountain slopes.

Glacially scoured ridge tops have been strongly modified by continental ice.

The prominent features are ridge tops and ridge noses with exposed bedrock.

These areas have slopes that range from 10 to 45 percent. Soils on these

landforms are shallow to moderately deep, weak to moderately developed with

medium and moderately fine textures. The major soils are classified as Lithic

Andic, or Typic Cryochrepts. Rock outcrops occupy more than 50 percent of the

area. The dominant potential natural vegetation is subalpine fir-whitebark

pine, and subalpine fir. This landform component makes up 40 percent of the

LTA.

The dissected mountain slopes (fluvial) landscape is one that is

weathering-in-place. It is chemical weathering further affected by colluvial

action. Slope gradients range from 30 to 60 percent. Soils on these landforms

are moderately deep to deep, weak to moderate development, with medium and

moderately fine textures. The major soils are classified as Andic Cryochrepts,

Andeptic and Typic Cryoboralfs, and Typic or Argic Cryoborolls. Rock outcrops

occupy less than 10 percent of the area. The dominant potential natural

vegetation is Douglas-fir and subalpine fir. This landform component

represents 60 percent of the LTA.

Compiled by: Dean Sirucek, Flathead National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 397
LTA70-M333C

LTA70-M333B

LTA70-M333D

FROST SHATTERED MOUNTAIN RIDGE TOPS, METASEDIMENTARY (BELT)

Location: This unit is located in the Whitefish, Cabinets, Purcell, Salish,

Bitterroot, Swan, Mission, and Flathead Mountain ranges of the Clark Fork,

Kootenai, and Flathead River basin in northwest Montana.

 Acreage by Section

 70-M333C 60,686

 70-M333B 153,508

 70-M333D 518,308

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a alpine landscape

setting which is typically composed of a ridge top landform. Parent materials

are volcanic ash overlying weakly weathered, moderately metamorphosed

Proterozoic metasedimentary bedrock composed of argillites, siltites,

quartzites, dolomites and limestones. There are inclusions of other bedrocks,

such as granite, in this map unit.

Accessory Characteristics: The primary soils are shallow to moderately deep

with very gravelly medium textures. The vegetation is a mosaic of coniferous

forest, mountain shrubland, and mountain grasslands. Mean annual 

precipitation ranges from 102 to 279 centimeters (40 to 110 inches). The

elevation range is 1,341 to 2,758 meters (4400 to 9100 feet. The dominant

slopes have gradients of 10 to 40 percent. This map unit is undivided to

slightly dissected by streams, with the pattern being dendritic where present.

LTA Components: This landtype association consists of glacially scoured,

frost shattered ridge tops.

Glacially scoured, frost shattered ridge tops have been strongly modified by

continental ice, alpine ice, and frost action. The prominent features are

ridge tops that have been rounded or scoured by the previously mentioned

actions. Exposed bedrock comprises 10 to 40 percent of the area. These areas

have slopes that range from 5 to 50 percent. Soils on these landforms are

shallow to moderately deep and weakly developed with very gravelly medium

textures. The major soils are classified as Lithic Cryochrepts and Andic

Cryochrepts. The dominant potential natural vegetation is subalpine fir,

mountain hemlock, and whitebark pine-subalpine fir. This landform component

makes up 90 percent of the map unit. There are up to 10 percent inclusions of

nivational hollows that occur in this map unit.

Compiled by: Dean Sirucek, Flathead National Forest; Louis Kuennen, Kootenai

National Forest; Skip Barndt, Lolo National Forest.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 398
LTA74-M333C

FROST SHATTERED MOUNTAIN RIDGE TOPS: SANDSTONES, SHALES, AND CARBONATES

Location: This unit is located in the Whitefish, Swan, and Flathead Mountain

ranges of the Flathead River basin in northwest Montana.

 Acreage by Section

 74-M333C 9,208

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a alpine landscape

settings, which is typically composed of a ridge top landform. Parent

materials are surface volcanic ash overlying weakly weathered Paleozoic and

Mesozoic sandstone, shale, and limestone bedrock.

Accessory Characteristics: The primary soils are shallow to moderately deep

with very gravelly medium textures. The vegetation is a mosaic of coniferous

forest and mountain shrublands and grasslands. Mean annual precipitation

ranges from 89 to 229 centimeters (35 to 90 inches). The elevation range is

1,371 to 2,438 meters (4500 to 8000 feet). The dominant slopes have gradients

of 15 to 40 percent. This map unit is undivided to slightly dissected by

streams with the pattern being subparallel or dendritic where present.

LTA Component: This landtype association consists of glacially scoured, frost

shattered ridge tops.

Glacially scoured, frost shattered ridge tops have been strongly modified by

continental ice, alpine ice, and frost action. The prominent features are

ridge tops that have been rounded by the previously mentioned actions. Exposed

bedrock comprises 10 to 40 percent of the area. These areas have slopes that

range from 15 to 50 percent. Soils on these landforms are shallow to

moderately deep and weakly developed with very gravelly medium textures. The

major soils are classified as Lithic Cryochrepts and Andic Cryochrepts. The

dominant potential natural vegetation is subalpine fir, and whitebark

pine-subalpine fir. This landform component makes up 95 percent of the map

unit. There are up to 5 percent inclusions of nivational hollows that occur in

this map unit.

Compiled by: Dean Sirucek, Flathead National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 399
LTA90-M333C

LTA90-M333B

MASS WASTED SLOPES: MIXED GEOLOGY

Location: This unit is located in the Swan, Salish, Flathead, Mission, and

Whitefish Mountain ranges of the Swan and Flathead River basins in northwest

Montana.

 Acreage by Section

 90-M333C 58,472

 90-M333B 1,358

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in both upland and

alpine landscape settings. Typically landslide areas are associated with

structural breakland, stream breakland, glacial troughwall, and glacial

moraine landforms. Parent materials are typically glacial tills underlain by

Paleozoic and Mesozoic sandstone and shale bedrock; or Proterozoic argillite,

siltite, quartzite, dolomite and limestone.

Accessory Characteristics: The primary soils are moderately deep to deep with

gravelly medium to moderately fine textures. The vegetation is primarily

coniferous forest with inclusions of shrublands. Mean annual precipitation

ranges from 51 to 229 centimeters (20 to 90 inches). The elevation range is

914 to 2,316 meters (3000 to 7600 feet). The dominant slopes have gradients of

20 to 60 percent. This unit is slightly to moderately dissected by streams

with the dominant stream pattern being deranged. Wetlands and small ponds are

a major component of this unit.

LTA Components: This landtype association consists of surficial landslide and

bedrock landslide deposits.

Surficial landslide deposits are formed in glacial till and colluvium parent

materials. Slope gradients range from 20 to 50 percent. Soils on these

landforms are moderately deep to deep and moderately developed with gravelly

medium textures. These soils are classified as Typic and Andeptic Cryoboralfs,

and Typic Eutroboralfs. Rock outcrop occurs on less than 10 percent of this

landscape component. The dominant potential natural vegetation is subalpine

fir and western redcedar. This component represents 60 percent of this unit.

Bedrock landslide landforms are formed in residual and colluvial parent

materials derived from native bedrock formations. Slope gradients range from

30 to 50 percent. Soils on these landforms are shallow to deep and moderately

developed with gravelly medium and moderately fine textures. These soils are

classified as Typic and Andeptic Cryoboralfs, Typic Eutroboralfs, and Andic

Cryochrept. Rock outcrop occurs on about 15 percent of this landscape

component. The dominant potential natural vegetation is subalpine fir,

Douglas-fir and western redcedar. This component represents 40 percent of this

unit.

Compiled by: Dean Sirucek, Flathead National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 400
CHAPTER 14

LTA Descriptions

Section M333D Bitterroot Mountains

This Section occurs in northern Idaho and western Montana. It generally

coincides with the Metasedimentary Mountains geomorphic area previously

described. Forty LTAs were mapped in this Section. See Appendix F for a

complete list of LTAs and their acreage. Map unit descriptions are preceded by

the following illustrations:

 

 Figure 60: Map showing location of M333D within the Northern Region

 Figure 61: M333D landscape photograph, Coeur d'Alene Mountains,

 Idaho Panhandle National Forests

 Figure 62: Map showing distribution of LTAS within M333D

 Figure 63: Bar chart showing abundance of landform groups within M333D

 Figure 64: Bar chart showing abundance of geologic material groups within

 M333D

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 401
LTA10-M333D

LTA10-M333B

LTA10-M333C

VALLEYS: RECENT COARSE ALLUVIUM

Location: This LTA is located in the inter-mountain valleys of the Flathead,

Clark Fork, and Kootenai River basins of northwest Montana.

 Acreage by Section

 10-M333D 160,219

 10-M333B 191,377

 10-M333C 63,658

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a valley bottom

landscape setting, which is composed of stream terraces, floodplains, and

alluvial basins. Parent materials are unstratified to stratified deposits of

sands, silts, and/or gravels underlain primarily by Proterozoic metasediments,

Cenozoic siltstones, and/or glacial deposits.

Accessory Characteristics: The primary soils are deep with extremely gravelly

coarse to medium textures. The vegetation is a mosaic of deciduous forest,

coniferous forest, and wet meadow/shrubland. Mean annual precipitation ranges

from 36 to 152 centimeters (14 to 60 inches). The elevation range of this LTA

is 758 to 1,970 meters (2500 to 6500 feet). The dominant slopes have gradients

of 3 to 15 percent. This LTA is moderately dissected by streams with the

dominant stream pattern being dendritic. Wetlands and river over-flow

channels are a major component of this LTA.

LTA Components: This landtype association consists of stream terraces,

floodplains, and alluvial basins.

Stream terraces are formed in coarse, stratified alluvium. These terraces have

slope gradients that range from 0 to 15 percent. Soils on these landforms are

deep, poorly developed, and mostly of sand and gravel. The soils vary from

moderately well drained to well drained. The major soils on the moderately

well drained sites are Oxyaquic Udifluvents, Typic Ustifluvents and Typic

Udifluvents. The major soils on the well drained sites are Dystric

Eutrochrepts, Andic Dystrochrepts and Typic Xerochrepts. Rock outcrops occur

less than 2 percent of the time. The dominant potential natural vegetation is

black cottonwood, Engelmann spruce, western redcedar, grand fir, Douglas-fir

and subalpine fir. This component represents 60 percent of the LTA.

Floodplains and alluvial basins are formed in coarse stratified or

unstratified alluvium. These areas have slope gradients that range from 0 to

10 percent. Soils on these landforms are deep, weakly developed and consist

mostly of sand, gravel, and silt. These soils vary from moderately well

drained to poorly drained. The major soils are classified as Typic

Endoaquents, or Typic and Aeric Endoaquepts. Rock outcrops occur less than 1

percent of the time. The dominant potential natural vegetation i s subalpine

fir, Engelmann spruce and Drummond's willow. This component represents 40

percent of the LTA.

Compiled by: Dean Sirucek, Flathead National Forest; Skip Barndt, Lolo

National Forest; Louis Kuennen, Kootenai National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 402
LTA11-M333D

LTA11-M333B

LTA11-M333C

VALLEYS: LACUSTRINE SEDIMENTS

Location: This unit is located in the inter-mountain valleys of the Clark

Fork, Flathead, and Kootenai River basins of northwest Montana.

 Acreage by Section

 11-M333D 111,455

 11-M333B 533,326

 11-M333C 11,821

LTA Setting and General Characteristics

Differentiating Characteristics: This unit occurs in a valley bottom landscape

setting, which is typically composed of glacial lacustrine deposits that have

level to slightly undulating topography. Parent materials consist of

stratified lake sediments of very fine sands, silts, and clays.

Accessory Characteristics: The primary soils are deep with medium to

moderately fine textures. The vegetation ranges from a continuous cover of

coniferous vegetation on the well drained sites to wet meadow/shrubland on the

poorly drained sites. Mean annual precipitation ranges from 36 to 152

centimeters (14 to 60 inches). The elevation range is 758 to 1,818 meters

(2500 to 6000 feet). The dominant slopes have gradients of 2 to 20 percent. 

This map unit is slightly dissected by streams. Where present, the dominant

stream pattern is dendritic. Wetlands and ponds are a major component of the

unit.

LTA Components: This landtype association consists of lacustrine terraces and

lacustrine basins.

Lacustrine terraces and lacustrine basins are formed in stratified lake

sediments. These landforms have dominant slope gradients ranging from 0 to 25

percent. Included with these landforms are terrace risers/scarps that have

slopes that range from 40 to 70 percent. Soils on these landforms are deep,

weak to moderately developed with medium and moderately fine textures. In

northwestern Montana the major soils on the forested, well-drained sites are

classified as Glossic Cryoboralfs, Typic Eutroboralfs, and Eutric

Glossoboralfs. In Section M333B additional major soils are Andic and Typic

Dystrochrept. In the lower-elevation, non-forested, valleys the soils are

classified as Typic Natrixeralfs and Typic Xerochrept. The dominant vegetation

is western redcedar, subalpine fir, grand fir, and Douglas-fir

The major soils on the poorly drained sites are classified as Aeric Epiaquepts

and Aquic Eutroboralfs with inclusions of Typic Borosaprists. Rock outcrop

occurs on less than 2 percent of this landscape component. Engelmann spruce,

Drummond's willow, and beaked sedge occur on the poorly drained sites.

Compiled by: Dean Sirucek, Flathead National Forest; Skip Barndt, Lolo

National Forest; Louis Kuennen, Kootenai National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 403
LTA12-M333D

LTA12-M333B

LTA12-M333C

VALLEYS: OUTWASH AND OTHER OLDER COARSE ALLUVIAL DEPOSITS

Location: This map unit is located in the inter-mountain valleys of the Clark

Fork, Flathead, and Kootenai River basins of northwest Montana.

 Acreage by Section

 12-M333D 181,889

 12-M333B 428,208

 12-M333C 97,651

LTA Setting and General Characteristics

Differentiating Characteristics: This unit occurs in valley bottom landscape

settings, which are typically composed of glacial outwash plains or outwash

terraces that have undulating surfaces. Steep escarpments form the front of

the some of the terraces. Parent materials consist of either stratified or

unstratified glacial fluvial deposits of sand and gravel material. These

deposits are typically underlain by glacial moraine deposits or Proterozoic

metasedimentary bedrock.

Accessory Characteristics: The primary soils are deep with extremely gravelly

coarse textures. These soils are typically excessively well drained with

inclusions of poorly drained soils. The vegetation is primarily coniferous

forest with areas of wet meadow/shrubland. Mean annual precipitation ranges

from 36 to 140 centimeters (14 to 55 inches). The elevation range of this unit

is 758 to 1,667 meters (2500 to 5500 feet). The dominant slopes have gradients

of 2 to 20 percent. This map unit is moderate to highly dissected by streams

or rivers with the dominant stream pattern being dendritic. Wetlands and

riparian areas are important components of this unit.

LTA Components: This landtype association consists of glacial outwash plains

and outwash terraces.

These glacial outwash plains and outwash terraces are formed in coarse,

stratified or unstratified glacial fluvial sediments. Slope gradients range

from 0 to 25 percent with gradients up to 50 percent on the terrace risers.

Soils on these landforms are deep, weakly developed with extremely gravelly

coarse textures. The major soils are classified as Dystric Eutrochrepts, 

Typic Dystrochrept, Andic Dystrochrepts, and Andic Ustochrepts. Rock outcrop

occurs on less than 5 percent of this map unit. The dominant vegetation is

Douglas-fir, western redcedar, subalpine fir, and Englelmann spruce.

Compiled by: Dean Sirucek, Flathead National Forest; Skip Barndt, Lolo

National Forest; Louis Kuennen. Kootenai National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 404
LTA14-M333D

VALLEYS: RECENT FINE ALLUVIUM

Location: This unit is located in the Bitterroot and St. Joe Mountains of

Idaho in the Kelly Creek, St. Joe, and Coeur d' Alene River Basins.

 Acreage by Section

 14-M333D 41,867

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a valley bottom

landscape setting, which is typically composed of floodplains, alluvial

basins, and stream terraces. Parent materials are recent, fine, alluvial

deposits primarily underlain by Belt series metasediments and granitics of the

Idaho Batholith

Accessory Characteristics: The primary soils are moderately deep to deep with

moderately fine to fine textures. The vegetation is a mosaic of moist to wet

coniferous forest, riparian shrub communities, and mesic to wet meadows. Mean

annual precipitation ranges from 76 to 114 cms. (30 to 45 inches). The

elevation range is 610 to 1524 meters (2000 to 5000 feet). The dominant slopes

have gradients of 0 to 10 percent. This unit is moderately dissected by

streams, with the dominant stream pattern being dendritic. Wetlands and ponds

are a major component of this unit.

LTA Components: This landtype association consists of floodplains, alluvial

basins, and stream terraces.

Floodplains and alluvial basins are formed in moderately fine-textured recent

alluvium. Slope gradients range from 0 to 3 percent. Soils on these landforms

are deep, weakly to moderately developed, and consist mostly of silt loam and

silty clay loam textures. These soils are classified as Typic Cryaquepts,

Aquic Cryochrepts, and Cumulic Cryaquolls. Rock outcrop occurs on less than 1

percent of this landscape component. The dominant potential natural vegetation

are mesic to wet grass/sedge associations, willow/cottonwood/alder

associations, and western redcedar and subalpine fir series. This component

represents 80 percent of this unit.

Stream terraces are formed in mixed alluvium. Slope gradients range from 2 to

10 percent. Soils on these landforms are deep, weakly developed, and consist

mostly of medium to moderately fine textures. These soils are classified as

Typic Eutrochrepts and Dystric Cryochrepts. Rock outcrop occurs on less than 1

percent of this landscape component. The dominant potential natural vegetation

series are western redcedar, grand fir, and subalpine fir. This component

represents 20 percent of this unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 405
LTA17-M333D

HILLS AND PLATEAUS: LOESS

Location: This unit is located in west-central Idaho on the Palouse Prairie,

adjacent to the Potlatch River Canyon.

 Acreage by Section

 17-M333D 99,346

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a low to mid

elevation, gently to moderately sloping landscape setting which is typically

composed of low relief rolling hills. Parent materials are a layer of wind

blown loess, 2 to 30 meters (6 to 100 feet) thick underlain primarily by

Columbia flood basalts.

Accessory Characteristics: The primary soils are deep to very deep with silt

loam surface textures and silt loam to silty clay loam subsurface textures.

The vegetation is a mosaic of prairie grasslands with forest vegetation at the

higher elevations. Mean annual precipitation ranges from 51 to 76 cms. (20 to

30 inches). The elevation range is 610 to 914 meters (2000 to 3000 feet). The

dominant slopes have gradients of 5 to 30 percent. This unit is slightly to

moderately dissected by streams, with the dominant stream pattern being

dendritic. Wetlands are a minor component of this unit.

LTA Components: This landtype association consists of low relief rolling

hills.

Low relief rolling hills are formed in wind-blown loess exhibiting dune

formations, in the Palouse Prairie near the Potlatch River Canyon. Slope

gradients range from 5 to 30 percent. Soils on these landforms are deep to

very deep, highly developed, and consist of silt loam surface textures and

silt loam and silty clay loam subsurface textures. These soils are classified

as Ultic Argixerolls, Ultic Haploxeralfs, and Pachic Ultic Haploxerolls. Rock

outcrop are uncommon on this landscape component. The dominant potential

natural vegetation is bluebunch wheatgrass and Idaho fescue in the prairie

grasslands and ponderosa pine in forested areas. 

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 406
LTA20-M333D

LTA20-M333B

LTA20-M333C

BREAKS: METASEDIMENTARY (BELT)

Location: This unit is located in the St. Joe, Coeur d'Alene, Clearwater,

Whitefish, Swan, Mission, Bitterroot, Purcell, Salish, Cabinet, and Flathead

mountains. These are part of the Clark Fork, Coeur d'Alene, St. Joe,

Clearwater, Flathead, and Kootenai River basins in northwest Montana and north

Idaho.

 Acreage by Section

 20-M333D 1,000,850

 20-M333B 212,411

 20-M333C 163,793

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in both the upland and

alpine landscape settings, which are typically composed of structural break

and stream break landforms. Parent materials are volcanic ash overlying weakly

weathered, moderately metamorphosed Proterozoic metasedimentary bedrock

composed of argillites, siltites, quartzites, dolomites, and limestones.

Accessory Characteristics: The primary soils are shallow to moderately deep

with very gravelly medium textures. The vegetation is a mosaic of coniferous

forest, and mountain shrub/grass lands. Mean annual precipitation ranges from

36 to 229 centimeters (14 to 90 inches). The elevation range is 655 to 2,590

meters (2150 to 8500 feet). The dominant slopes have gradients of 55 to 70

percent. This unit is slightly to moderately dissected by streams with the

dominant stream patterns being sub-parallel and parallel. Major streams or

rivers are typically located at the base of the stream breaks landforms.

Lakes and ponds are a minor component of this unit.

LTA Components: This landtype association consists of structural and stream

breaks.

Structural breaks are formed in colluvial materials from weakly weathered

metasedimentary bedrock. Slope gradients range from 50 to 100 percent. Soils

on these landforms are shallow to moderately deep and weakly developed with

very gravelly medium textures. These soils are classified as Lithic, Typic and

Andic Dystrochrepts on warm sites; and Lithic, Typic, and Andic Cryochrepts on

colder sites. Rock outcrop and talus occur on 20 to 80 percent of this

landscape component. The dominant potential natural vegetation on the warmer

sites is Douglas-fir; and on the cooler sites are subalpine fir and whitebark

pine-subalpine fir. This component represents 80 percent of this unit.

Stream breaks are the steep, mountain slopes adjacent to stream drainages,

some of these steep slopes are dissected and other are not. Stream breaks are

formed in colluvial materials from weakly weathered metasedimentary bedrock.

Slope gradients range from 50 to greater than 100 percent. Soils on these

landforms are shallow to moderately deep and weakly developed with very

gravelly medium textures. These soils are classified as Lithic and Typic

Dystrochrepts on the warmer sites; and Lithic, Typic and Andic Cryochrepts on

the cooler sites. In Idaho, the soils have thicker volcanic ash surface

layers. Here the major soils on the well drained sites are classified as Typic

Udivitrands and Alfic Udivitrands, with xeric phases of these occurring on

some of the southerly aspects. Humic Udivitrands occur in the more poorly

drained sites. Rock outcrop and talus occur on less than 10 to over 50 percent

of this landscape component. The dominant potential natural vegetation is

Douglas-fir, western redcedar, western hemlock, grand fir, and subalpine fir.

This component represents 20 percent of this unit.

Compiled by: Dean Sirucek, Flathead National Forest; Skip Barndt, Lolo

National Forest; Louis Kuennen, Kootenai National Forest, Jerry Niehoff, Idaho

Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 407
LTA21-M333D

BREAKS: HIGHLY WEATHERED GRANITICS

Location: This unit is located in the Clearwater Mountains of north-central

Idaho in the Weitas, Cayuse, and North Fork Clearwater River Basins.

 Acreage by Section

 21-M333D 73,456

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a very steep, deeply

eroded landscape setting which is typically composed of stream or structural

breaks. Parent materials are a mixed Mazama volcanic ashcap of variable

thickness underlain by highly weathered granitics of the Idaho Batholith.

Accessory Characteristics: The primary soils are shallow to moderately deep

with textures ranging from silt loams to very gravelly sandy loams. The

vegetation is primarily coniferous forest with numerous rock outcrops. Mean

annual precipitation ranges from 89 to 152 cms. (35 to 60 inches). The

elevation range is 762 to 1524 meters (2500 to 5000 feet). The dominant slopes

have gradients of 60 to 100 percent. This unit is moderately to highly

dissected by streams, with the dominant stream pattern being parallel.

Wetlands are generally not present in this unit.

LTA Components: This landtype association consists primarily of stream

breaks, some of which may have formed along structural breaks.

Stream breaks are formed in colluvial materials from highly weathered granitic

rocks of the Idaho Batholith with a mixed surface layer of Mazama volcanic ash

of varying thickness. Slope gradients range from 60 to 100 percent. Soils on

these landforms are shallow to moderately deep, weakly developed with silt

loam to sandy loam surface textures and very gravelly to cobbly subsurface

textures. These soils are classified as Typic Dystrochrepts, Andic

Dystrochrepts, and Vitrandic Cryochrepts. Rock outcrop occurs on 15 to 35

percent of this landscape component. The dominant potential natural vegetation

series are western redcedar, grand fir, and subalpine fir. This component

represents 100 percent of this unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 408
LTA22-M333D

BREAKS: WEAKLY WEATHERED GRANITICS

Location: This unit is located in the headwaters of Lolo Creek in the

Bitterroot Mountains east of Lolo Pass on the Montana/Idaho border.

 Acreage by Section

 22-M333D 9,036

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a very steep, deeply

eroded landscape setting which is typically composed of stream or structural

breaks. Parent materials are a mixed Mazama volcanic ashcap of variable

thickness underlain by weakly weathered granitics of the Idaho and Lolo

Batholiths.

Accessory Characteristics: The primary soils are shallow to moderately deep

with textures ranging from silt loams to very gravelly sandy loams. The

vegetation is primarily coniferous forest with numerous rock outcrops. Mean

annual precipitation ranges from 114 to 203 cms (45 to 80 inches). The

elevation range is 762 to 1524 meters (5000 to 7500 feet). The dominant slopes

have gradients of 60 to 100 percent. This unit is moderately to highly

dissected by streams, with the dominant stream pattern being parallel to

dendritic. Wetlands are generally not present in this unit.

LTA Components: This landtype association consists primarily of stream

breaks, some of which may have formed along structural breaks.

Stream breaks are formed in colluvial materials from weakly weathered granitic

rocks of the Idaho and Lolo Batholiths with a mixed surface layer of Mazama

volcanic ash of varying thickness. Slope gradients range from 60 to 100

percent. Soils on these landforms are shallow to moderately deep, weakly

developed with silt loam to gravelly sandy loam surface textures, and very

gravelly to cobbly subsurface textures. These soils are classified as Typic

Cryochrepts, Dystric Cryochrepts, and Vitrandic Cryochrepts. Rock outcrop

occurs on 15 to 35 percent of this landscape component. The dominant potential

natural vegetation series are subalpine fir, Douglas-fir, and grand. This

component represents 100 percent of this unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 409
LTA20-M333D

LTA20-M333B

LTA20-M333C

BREAKS: METASEDIMENTARY (BELT)

Location: This unit is located in the St. Joe, Coeur d'Alene, Clearwater,

Whitefish, Swan, Mission, Bitterroot, Purcell, Salish, Cabinet, and Flathead

mountains. These are part of the Clark Fork, Coeur d'Alene, St. Joe,

Clearwater, Flathead, and Kootenai River basins in northwest Montana and north

Idaho.

 Acreage by Section

 20-M333D 1,000,850

 20-M333B 212,411

 20-M333C 163,793

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in both the upland and

alpine landscape settings, which are typically composed of structural break

and stream break landforms. Parent materials are volcanic ash overlying weakly

weathered, moderately metamorphosed Proterozoic metasedimentary bedrock

composed of argillites, siltites, quartzites, dolomites, and limestones.

Accessory Characteristics: The primary soils are shallow to moderately deep

with very gravelly medium textures. The vegetation is a mosaic of coniferous

forest, and mountain shrub/grass lands. Mean annual precipitation ranges from

36 to 229 centimeters (14 to 90 inches). The elevation range is 655 to 2,590

meters (2150 to 8500 feet). The dominant slopes have gradients of 55 to 70

percent. This unit is slightly to moderately dissected by streams with the

dominant stream patterns being sub-parallel and parallel. Major streams or

rivers are typically located at the base of the stream breaks landforms.

Lakes and ponds are a minor component of this unit.

LTA Components: This landtype association consists of structural and stream

breaks.

Structural breaks are formed in colluvial materials from weakly weathered

metasedimentary bedrock. Slope gradients range from 50 to 100 percent. Soils

on these landforms are shallow to moderately deep and weakly developed with

very gravelly medium textures. These soils are classified as Lithic, Typic and

Andic Dystrochrepts on warm sites; and Lithic, Typic, and Andic Cryochrepts on

colder sites. Rock outcrop and talus occur on 20 to 80 percent of this

landscape component. The dominant potential natural vegetation on the warmer

sites is Douglas-fir; and on the cooler sites are subalpine fir and whitebark

pine-subalpine fir. This component represents 80 percent of this unit.

Stream breaks are the steep, mountain slopes adjacent to stream drainages,

some of these steep slopes are dissected and other are not. Stream breaks are

formed in colluvial materials from weakly weathered metasedimentary bedrock.

Slope gradients range from 50 to greater than 100 percent. Soils on these

landforms are shallow to moderately deep and weakly developed with very

gravelly medium textures. These soils are classified as Lithic and Typic

Dystrochrepts on the warmer sites; and Lithic, Typic and Andic Cryochrepts on

the cooler sites. In Idaho, the soils have thicker volcanic ash surface

layers. Here the major soils on the well drained sites are classified as Typic

Udivitrands and Alfic Udivitrands, with xeric phases of these occurring on

some of the southerly aspects. Humic Udivitrands occur in the more poorly

drained sites. Rock outcrop and talus occur on less than 10 to over 50 percent

of this landscape component. The dominant potential natural vegetation is

Douglas-fir, western redcedar, western hemlock, grand fir, and subalpine fir.

This component represents 20 percent of this unit.

Compiled by: Dean Sirucek, Flathead National Forest; Skip Barndt, Lolo

National Forest; Louis Kuennen, Kootenai National Forest, Jerry Niehoff, Idaho

Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 410
LTA24-M333D

BREAKS: VOLCANICS

Location: This unit is located in the Clearwater River Basin of west-central

Idaho.

 Acreage by Section

 24-M333D 14,019

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a very steep, deeply

eroded landscape setting which is typically composed of stream breaks. Parent

materials are weakly to moderately weathered Columbia flood basalts overlain

with a variable thickness of wind-blown loess.

Accessory Characteristics: The primary soils are shallow to moderately deep

with textures ranging from silt loams to very cobbly loams. The vegetation is

a mosaic of grasslands with some shrubland and coniferous forest inclusions.

Mean annual precipitation ranges from 51 to 89 cms (20 to 35 inches). The

elevation range is 458 to 914 meters (1500 to 3000 feet). The dominant slopes

have gradients of 60 to 80 percent. This unit is moderately dissected by

streams, with the dominant stream pattern being parallel. Wetlands are

generally not present in this unit.

LTA Components: This landtype association consists primarily of stream

breaks.

Stream breaks are formed in colluvial materials from weakly to moderately

weathered Columbia flood basalts with a variable layer of loess mixed in the

surface layer. Slope gradients range from 60 to 80 percent. Soils on these

landforms are shallow to moderately deep, weakly developed with silt loam to

loam surface textures and very gravelly to cobbly subsurface textures. These

soils are classified as Typic Haploxerolls, Lithic Argixerolls, and Ultic

Argixerolls. Rock outcrop occurs on 20 to 40 percent of this landscape

component. The dominant potential natural vegetation series are Idaho fescue,

bluebunch wheatgrass, with ponderosa pine, Douglas-fir, and grand fir in the

moister settings. This component represents 90 percent of this unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 411
LTA26-M333D

BREAKS: MODERATELY WEATHERED GNEISSES, QUARTZITES AND SCHISTS

Location: This unit is located in the North Fork Clearwater River Basin in

north central Idaho.

 Acreage by Section

 26-M333D 4,712

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is composed of dissected

stream breaks. Parent materials are moderately weathered gneiss, quartzite,

and schist associated with the Idaho Batholith.

Accessory Characteristics: The primary soils are moderately deep to deep

sandy loams and loams. The vegetation is a mosaic of grassland and coniferous

forest. Mean annual precipitation ranges from 46 to 114 centimeters (18 to 45

inches). The elevation range is 550 to 2000 meters (1800 to 6600 feet). The

dominant slopes have gradients of 50 to 80 percent. This unit is moderately

dissected by streams, with the dominant stream pattern being parallel. 

LTA Components: This landtype association consists of dissected breaks.

Breaks are formed in mixed volcanic ash influenced loess, residuum and

colluvium of felsic metamorphic lithology. Soils on these landforms are

moderately deep to very deep, moderately developed loams and sandy loams with

sandy or loamy substrata. These soils are classified as Ultic Haploxerolls,

Typic Dystrochrepts, Dystric Cryochrepts, and Andic Dystrochrepts. Rock

outcrop is less than 25 percent of the unit. The dominant potential natural

vegetation at low elevations is bluebunch wheatgrass and Idaho fescue, at

mid-elevations Douglas-fir and grand fir, and at high elevations subalpine

fir.

Compiled by: Pat Green, Nez Perce National Forest, and Jim Mital, Clearwater

National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 412
LTA28-M333D

LTA28-M333A

DISSECTED BREAKS: METASEDIMENTARY (BELT)

Location: This unit is located in the Coeur d' Alene Mountains of the

Bitterroot range, which are part of the Coeur d' Alene River basin of northern

Idaho.

 Acreage by Section

 28-M333D 316,745

 28-M333A 429

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a low to mid

elevation, moderately steep to steep sloping, mountain sideslope and stream

break landscape setting, which is typically composed of dissected lower

mountain slopes and stream breaks comprised of colluvium and residuum. Parent

materials are surface volcanic ash overlying weakly to moderately weathered

quartzites, siltites and argillites from Precambrian metasedimentary bedrock.

Accessory Characteristics: The primary soils are shallow to deep loams and

sandy loams, with a component of rock outcrop and scree. The vegetation is a

mosaic of coniferous forest. Mean annual precipitation ranges from 64 to

140 centimeters (25 to 55 inches). The elevation range of this unit is 655 to

1524 meters (2150 to 5000 feet). The dominant slopes have gradients of 45 to

80 percent. This unit is moderately to highly dissected by streams, with the

dominant stream pattern being parallel. The landscapes of this area are all

generally under 5000 feet and in a high rain-on-snow frequency area.

LTA Components: This landtype association consists of lower mountain slopes

and breaks which have alternating dissected draws and spur ridges.

Dissected draws occur on moderately steep to steep slopes, and are formed in

metasediments that consist of quartzites, siltites and argillites. The slope

gradients range from 45 to 80 percent. Soils on these landforms are shallow to

deep, weakly to moderately weathered and medium textured. The major soils on

the well drained sites within the draw are classified as Typic Udivitrands and

Alfic Udivitrands, xeric phases of these occur on some of the southerly

aspects. Humic Udivitrands occur in the more poorly drained sites. Rock

outcrop or scree occupies 10 to 30 percent of this unit. The dominant

potential natural vegetation on the well drained sites are western redcedar,

western hemlock and grand fir. The dominant potential natural vegetation on

the poorly drained sites is western redcedar. This component represents about

50 percent of this unit

Non-dissected spur ridges occur on moderately steep to steep slopes and are

formed in the same Belt metasediment rock types stated in the landscape

component above. The slope gradients range from 45 to 80 percent. Soils on

these landforms are shallow to deep, weakly to moderately weathered and 

medium textured. The major soils are classified as Typic Udivitrands, with

xeric phases on dryer, southerly aspects. Moderately weathered soils consist

of Alfic Udivitrands and Alfic Vitrixerands. Rock outcrop and scree occupies

10 to 30 percent of this unit. The dominant potential natural vegetation is

western redcedar, western hemlock, grand fir and Douglas-fir. This component

represents about 50 percent of this unit.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 413
LTA26-M333D

BREAKS: MODERATELY WEATHERED GNEISSES, QUARTZITES AND SCHISTS

Location: This unit is located in the North Fork Clearwater River Basin in

north central Idaho.

 Acreage by Section

 26-M333D 4,712

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is composed of dissected

stream breaks. Parent materials are moderately weathered gneiss, quartzite,

and schist associated with the Idaho Batholith.

Accessory Characteristics: The primary soils are moderately deep to deep

sandy loams and loams. The vegetation is a mosaic of grassland and coniferous

forest. Mean annual precipitation ranges from 46 to 114 centimeters (18 to 45

inches). The elevation range is 550 to 2000 meters (1800 to 6600 feet). The

dominant slopes have gradients of 50 to 80 percent. This unit is moderately

dissected by streams, with the dominant stream pattern being parallel. 

LTA Components: This landtype association consists of dissected breaks.

Breaks are formed in mixed volcanic ash influenced loess, residuum and

colluvium of felsic metamorphic lithology. Soils on these landforms are

moderately deep to very deep, moderately developed loams and sandy loams with

sandy or loamy substrata. These soils are classified as Ultic Haploxerolls,

Typic Dystrochrepts, Dystric Cryochrepts, and Andic Dystrochrepts. Rock

outcrop is less than 25 percent of the unit. The dominant potential natural

vegetation at low elevations is bluebunch wheatgrass and Idaho fescue, at

mid-elevations Douglas-fir and grand fir, and at high elevations subalpine

fir.

Compiled by: Pat Green, Nez Perce National Forest, and Jim Mital, Clearwater

National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 414
landforms are shallow to moderately deep and weakly developed with very

gravelly medium textures. The major soils are classified as Andic, Dystric and

Lithic Cryochrepts, and Vitric Haplocryands, and Vitric Fulvicryands. Rock

outcrops occupy more than 40 percent of the area. The dominant potential

natural vegetation is subalpine fir, and whitebark pine-subalpine fir. This

component represents 45 percent of the LTA.

Compiled by: Dean Sirucek, Flathead National Forest; Louis Kuennen, Kootenai

National Forest; Skip Barndt, Lolo National Forest, Jim Mital, Clearwater

National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 415
LTA41-M333D

STEEP GLACIATED MOUNTAIN SLOPES: GRANITICS

Location: This unit is located in the Bitterroot Mountains on the

Idaho/Montana border primarily in the Upper Lochsa River and Lolo Creek

Basins.

 Acreage by Section

 41-M333D 24,915

LTA Setting and General Characteristics

Differentiating characteristics: This LTA occurs in a steep, alpine glacial

landscape setting, which is typically composed of steep glacial slopes and

headwalls. Parent materials are granitics of the Idaho Batholith overlain by a

variable thickness of Mazama volcanic ash.

Accessory Characteristics: The primary soils are shallow to moderately deep

with textures ranging from silt loam to loam surface textures and very

gravelly to cobbly loam to sandy loam subsurface layers. The vegetation is a

mosaic of coniferous forest, subalpine meadows, and rock outcrops. Mean annual

precipitation ranges from 127 to 191 cms. (50 to 75 inches). The elevation

range is 1524 to 2439 (5000 to 8000 feet). The dominant slopes have gradients

of 30 to 60 percent. This unit is moderate to highly dissected by streams,

with the dominant stream pattern being parallel. Wetlands and subalpine ponds

are a major component of this unit.

LTA Components: This landtype association consists of a complex of steep,

alpine glaciated slopes and headwalls intermixed across the landscape.

Steep, alpine, glaciated slopes and headwalls are formed in granitics of the

Idaho Batholith with a mixed surface layer of Mazama volcanic ash of varying

thickness. Slope gradients range from 30 to 60 percent. Soils on these

landforms are shallow to moderately deep, weakly to moderately developed, and

consist mostly of silt loam and loam surface textures and very gravelly,

cobbly, and bouldery loamy subsurface textures. These soils are classified as

Andic Cryochrepts, Dystric Cryochrepts, and Vitric Haplocryands. Rock outcrop

occurs on 20 to 50 percent of this landscape component. The dominant

potential natural vegetation are subalpine fir, whitebark pine, and wet

grass/sedge meadows.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 416
LTA45-M333D

LTA45-M332E

LTA45-M332B

WEAKLY GLACIATED MOUNTAIN SLOPES AND RIDGES: GRANITE

Location: This unit is located in the Bitterroot and Sapphire mountain ranges

of western Montana in the Bitterroot and Upper Clark Fork River Basins.

 Acreage by Section

 45-M333D 3,610

 45-M332B 83,690

 45-M332E 2,117

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a high elevation

broad ridgetop position which is typically composed of weakly expressed

glaciated slopes and basins that were formed by ice cap glaciers, minor valley

glaciers, and strong periglacial frost shattering. Parent materials are a

complex of frost shattered residuum and colluvium, intermixed with glacial

till derived from moderately weathered granite.

Accessory Characteristics: The primary soils are shallow to deep, coarse

soils with numerous rock fragments and have a volcanic ash surface layer. The

vegetation is a mosaic of coniferous forest, stunted wind-deformed forest, and

occasional small wet meadows. Mean annual precipitation ranges from 102 to 140

centimeters (40 to 55 inches). The elevation range is 2073 to 2743 meters

(6800 to 9000 feet). The dominant slopes have gradients of 20 to 55 percent.

This unit is slightly dissected by streams, with the dominant stream pattern

being dendritic. Wetlands and ponds are a minor component of this unit.

LTA Components: This landtype association consists of weakly developed

glacial cirques and frost shattered mountain ridge tops.

Weakly developed glacial cirques are formed in residuum, colluvium, and till

derived from a variety of rock types. Slope gradients range from 20 to 55

percent. Soils on this landform are shallow to deep and somewhat excessively

drained. These soils are weakly developed and consist of extremely bouldery

loam volcanic ash surface layers overlying very stony loamy sand substrata.

The dominant soils are classified as Lithic and Andic Cryochrepts. Rock

outcrop occurs on about 10 percent of this landscape component. The dominant

potential natural vegetation is alpine larch-subalpine fir, whitebark

pine-subalpine fir, and subalpine fir series. This component represents 65

percent of this unit.

Frost shattered mountain ridge tops are formed in residuum and colluvium.

Slope gradients range from 20 to 50 percent. Soils on this landform are

shallow to deep and somewhat excessively drained. These soils are weakly

developed and consist of very stony loam volcanic ash surface layers overlying

very cobbly coarse sandy loam substrata. The dominant soils are classified as

Lithic and Andic Cryochrepts. Rock outcrop occurs on about 15 percent of this

landscape component. The dominant potential natural vegetation is whitebark

pine-subalpine fir, alpine larch-subalpine fir, and subalpine fir series. 

This component represents 35 percent of this unit.

Compiled by: Ken McBride, Bitterroot National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 417
LTA46-M333D

ALPINE TROUGHS AND TROUGHWALLS: GRANITICS

Location: This unit is located in the Bitterroot Mountains of Idaho in the

Cayuse River Basin.

 Acreage by Section

 46-M333D 7,904

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs at higher elevations,

in a gentle to steep, alpine glacial landscape setting, which is typically

composed of alpine trough bottoms and troughwalls. Parent materials are Mazama

volcanic ash overlying weakly weathered granitic tills and bedrock of the

Idaho Batholith.

Accessory Characteristics: The primary soils are shallow to moderately deep

with textures ranging from silt loam to loam surface textures and very

gravelly to cobbly loam subsurface layers. The vegetation is a mosaic of

coniferous forest and rock outcrops. Mean annual precipitation ranges from 152

to 178 cms. (60 to 70 inches). The elevation range is 1219 to 1524 meters

(4000 to 5000 feet). The dominant slopes range from 1 percent in the trough

bottoms to more than 60 percent on the troughwalls. This unit is moderate to

highly dissected by streams, with the dominant stream pattern being parallel.

Wetlands and moist seeps a major component of this unit.

LTA Components: This landtype association consists of glacial troughwalls and

glacial trough bottoms.

The glacial troughwalls are formed in granitics of the Idaho Batholith with a

mixed surface layer of Mazama volcanic ash of varying thickness. Slope

gradients range from 40 to more than 60 percent. Soils on these landforms are

shallow to moderately deep, weakly to moderately developed, and consist mostly

of silt loam and loam surface textures and very gravelly, cobbly, and bouldery

loamy subsurface textures. These soils are classified as Andic Cryochrepts,

Typic Cryochrepts, and Dystric Cryochrepts. Rock outcrop occurs on 10 to 30

percent of this landscape component. The dominant potential natural vegetation

are subalpine fir, grand fir, and alder communities in moist seeps. This

component represents about 70 percent of this unit.

The trough bottoms consist of glacial tills and glacio-fluvial materials from

Idaho Batholith granitics with a mixed surface layer of Mazama volcanic ash of

varying thickness. Slope gradients range from 1 to 30 percent. Soils on these

landforms are moderately deep, weakly to moderately developed, and consist

mostly of silt loam and loam surface textures and mostly unstratified very

gravelly, and cobbly, loamy subsurface textures. These soils are classified as

Andic Cryochrepts, Dystric Cryochrepts, and Typic Haplocryands. Rock outcrops

are uncommon. The dominant potential natural vegetation are subalpine fir,

grass/sedge associations, and alder communities in moist seeps and wetlands.

This component represents about 30 percent of this unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 418
LTA47-M333D

ALPINE TROUGHS AND TROUGHWALLS: METASEDIMENTARY (BELT)

Location: This unit is located in the Clark Fork, Coeur d' Alene, St. Joe,

Clearwater, Flathead, and Kootenai river basins of northwest Montana and

northern Idaho.

 Acreage by Section

 47-M333D 49,434

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs at the higher

elevations, in a gentle to steep alpine glacial setting, which is typically

composed of alpine trough bottoms and troughwalls. Parent materials are

surface volcanic ash overlying weakly weathered tills consisting of

quartzites, siltites, limestones, and argillites from Precambrian

metasedimentary bedrock.

Accessory Characteristics: The primary soils are shallow to deep sandy loams

and loams, with inclusions of rock outcrop, scree and avalanche chutes. The

vegetation is a mosaic of coniferous forest. Mean annual precipitation

ranges from 102 to 254 centimeters (40 to 100 inches). The elevation range of

this unit is 1273 to 2576 meters (4200 to 8500 feet). The dominant slopes

range from 1 percent in the trough bottoms to 85 percent on the steeper

troughwalls. This unit is slightly to highly dissected by streams, with the

dominant stream pattern being parallel. Wet sidehill areas and grassy parks

are a component of this LTA.

LTA Components: This landtype association consists of glacial troughwalls,

glacial trough bottoms, cirque headwalls, and moderately dissected structural

breaks.

These moderately steep to steep glaciated troughwalls consist of glacial till

from metasedimentary bedrock sources. The slope gradients range from 25 to 85

percent. Soils on these landforms are shallow to deep, weakly weathered and

medium textured. The major soils are classified as Vitric Haplocryands, Lithic

Cryochrepts, and Andic Cryochrepts. Rock outcrops occupy more than 40 percent

of some areas. The dominant potential natural vegetation is mountain hemlock

and subalpine fir. 

The trough bottoms consist of deep glacial tills and glacio-fluvial materials

from metasedimentary bedrock sources. The slope gradients range from 1 to 40

percent. soils on these landforms are deep, weakly weathered and medium

textured. The major soils on the well drained sites are classified as Vitric

Haplocryands. Vitric Fulvicryands mixed occur in depressional area and other

poorly drained sites. The dominant potential natural vegetation are mountain

hemlock and subalpine fir.

Cirque headwalls are formed in Proterozoic metasediments that consist of

argillites, siltites, limestones, and quartzites. Slope gradients range from

35 to 85 percent. Soils on these landforms are shallow to moderately shallow

and consist mainly of rock, sand, and gravel. The major soils are classified

as Lithic Cryochrepts and Andic Cryochrepts. Rock outcrops occupy more than 50

percent of the area. The dominant potential natural vegetation is subalpine

fir.

The moderately dissected breaks are developed on structural landforms. Slope

gradients range from 50 to 80 percent. Soils on these landforms are deep,

moderately developed and consist mostly rounded gravels and coarse silts/fine

sands. The major soils are classified as Andic Dystrochrepts and Andic

Cryochrepts. Rock outcrops occupy 15 to 25 percent of the area. The dominant

potential natural vegetation is western redcedar and subalpine fir.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forests and Louis

Kuennen, Kootenai National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 419
LTA50-M333D

LTA50-M333B

GLACIATED MOUNTAIN SLOPES: METASEDIMENTARY (BELT)

Location: This map unit is located primarily in the Flathead, Clark Fork and

Kootenai River basins of the Salish, Purcell, Bitterroot, and Cabinet

Mountains of northwest Montana.

 Acreage by Section

 50-M333D 66,747

 50-M333B 2,681,456

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in both valley and

upland settings mainly within a continentally glaciated landscape. Parent

materials are continental and/or alpine glacial debris underlain by

Proterozoic metasediments composed of argillites, siltites, limestones, and

quartzites.

Accessory Characteristics: The primary soils are moderately shallow to very

deep, very gravelly coarse silt and fine sandy loams. The major vegetative

cover is a dense coniferous forest with occasional grassy openings. Mean

annual precipitation ranges from 36 to 178 centimeters (14 to 70 inches). The

elevation range of this LTA is 667 to 1667 meters (2200 to 5500 feet). The

dominant slopes range from 20 to 50 percent. This map unit is slightly to

moderately dissected by streams with the dominant stream pattern being

dendritic. Bogs are a minor component of this map unit.

LTA Components: This landtype association has the classic subdued glacial

landforms which are comprised of convex, scoured ridges and sideslopes, and

valleys with deeper soils.

The straight side slopes and valleys are composed of a rounded ridges and

filled in valleys landform. These areas have slopes that range from 5 to 60

percent. The ridges were strongly scoured and then covered by glacial debris.

The drainage bottoms were filled in. The landforms (straight mountain slopes

and concave lower side slopes) have soils that are moderately deep to very

deep consisting of rock, fine sand and coarse silt. The major soils are

classified as Andic Dystrochrepts, Typic Dystrochrepts, Typic Eutrochrepts,

Typic Ustochrepts, Dystric Cryochrepts, and Andic Dystric Eutrochrept. Rock

outcrops occupy less than 15 percent of the area. This landform is covered

with a dense forest cover. The dominant potential natural vegetation series

include western redcedar, western hemlock, subalpine fir, and Douglas-fir. 

This component represents 65 percent of the unit.

The ridge top landform is comprised of the convex feature of the landscape.

The soils on this part of the landscape are moderately shallow to shallow. 

The major soils are classified as Lithic, Typic, and Andic Cryochrepts. The

dominant potential natural vegetation series is subalpine fir. This component

represents 35 percent of the map unit.

Compiled by: Louis Kuennen, Kootenai National Forest and Skip Barndt, Lolo

National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 420
LTA51-M333D

LTA51-M333A

GLACIATED MOUNTAIN SLOPES: GRANITICS

Location: This unit is located mostly in the Selkirk Mountains of the Priest,

Pend Oreille and Spokane River basins of northwestern Idaho and northeast

Washington.

 Acreage by Section

 51-M333D 3,788

 51-M333A 467,331

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a gentle to

moderately steep valley bottom, mountain sideslope and ridge landscape setting

at elevations that range from low to high. The unit is typically composed of

dissected and non dissected mountain slopes, valleys and ridges comprised of

alpine and continental till. Parent materials are surface volcanic ash

overlying substratum materials of glacial tills derived from Cretaceous

Kaniksu Batholith bedrock.

Accessory Characteristics: The primary soils are shallow to deep sands, with

a small component of rock outcrop and scree. The vegetation is a mosaic of

coniferous forest. Mean annual precipitation ranges from 76 to 178 centimeters

(30 to 70 inches). The elevation range is 800 to 2062 meters (2625 to 6765

feet). The dominant slopes have gradients of 15 to 55 percent. This unit is

slightly to highly dissected by streams, with the dominant stream pattern

being parallel. 

LTA Components: This landtype association consists of dissected and

non-dissected, continentally glaciated, convex ridges and concave valleys.

The glaciated convex ridges and mountain sideslopes were strongly scoured and

then covered by varying thickness of glacial tills. The slope gradients range

from near level to 60 percent. The drainage bottoms and toeslopes consist of

deep glacial tills and glacio-fluvial materials. The slope gradients range from

0 to 40 percent. Soils on the ridge and mountain sideslopes landforms are

shallow to deep, weakly weathered, and sandy textured. Soils in the drainage

bottoms and toeslopes are deep, weakly weathered, and sandy textured. The

major soils on the well drained sites are classified as Andic Cryochrepts and

Andic Dystrochrepts, with Andic Xerochrepts on the drier sites. The areas with

deeper ash caps are Vitric Haplocryands and Typic Udivitrands, Andic

Cryumbrepts and Andic Haplumbrepts occur in the more poorly drained sites.

Rock outcrop and scree occurs as an inclusion in the scoured ridge and

mountain sideslope landforms. The dominant potential natural vegetation on the

well drained, high elevation sites is subalpine fir with western hemlock,

western redcedar, grand fir and Douglas-fir occurring at low to mid

elevations. The dominant potential natural vegetation on the poorly drained

sites is subalpine fir at the higher elevations and cold air pockets at lower

elevations, and western redcedar at the mid and lower elevations.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 421
LTA57-M333D

LTA57-M332A

GLACIATED MOUNTAIN SLOPES: GNEISSES, QUARTZITES, AND SCHISTS

Location: This unit is located in mid to high elevation glaciated areas of

north central Idaho mainly in the Salmon and Clearwater River basins.

 Acreage by Section

 57-M333D 9,130

 57-M332A 54,631

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit is composed of gently to

moderately sloping alpine glaciated lands, including moraines, cirque basins,

and trough bottoms. Parent materials are poorly weathered gneiss, quartzite,

and schist associated with the Idaho batholith.

Accessory Characteristics: The primary soils are deep to very deep silt

loams, loams and sandy loams. The vegetation is coniferous forest. Mean annual

precipitation ranges from 89 to 127 centimeters (35 to 50 inches). The

elevation range is 1700 to 2500 meters (5500 to 8200 feet). The dominant

slopes have gradients of 10 to 50 percent. This unit is moderately dissected

by streams, with the dominant stream pattern being pinnate. Wetlands and lakes

are significant inclusions in basins and depressions.

LTA Components: This landtype association consists of moraines, cirque

basins, and trough bottoms.

Moraines are formed in volcanic ash influenced loess and glacial till of

felsic metamorphic lithology. Slope gradients range from 5 to 50 percent. 

Soils on these landforms are moderately deep to very deep, weakly developed

silt loams and gravelly sandy loams with cobbly loamy sand substrata. These

soils are classified as Andic Cryochrepts and Dystric Cryochrepts, and Andic

Cryumbrepts. Rock outcrop is less than 15 percent of the unit. The dominant

potential natural vegetation at mid elevations is grand fir, and at high

elevations subalpine fir. This component is 60 percent of the map unit.

Cirque basins are formed in volcanic ash influenced loess and glacial till of

felsic metamorphic lithology. Slope gradients range from 1 to 30 percent.

Soils on these landforms are moderately deep to very deep, weakly developed

silt loams and gravelly sandy loams with very cobbly loamy sand substrata.

These soils are classified as Andic Cryochrepts and Entic Cryumbrepts. Rock

outcrop is less than 10 percent of the unit. The dominant potential natural

vegetation is subalpine fir and sedge/shrub complexes. This component is 20

percent of the map unit.

Trough bottoms are formed in mixed volcanic ash influenced loess, glacial till

and stratified outwash of felsic metamorphic lithology. Slope gradients range

from 1 to 30 percent. Soils are these landforms are deep to very deep, weakly

developed silt loams, and gravelly sandy loams with very cobbly loamy sand or

sand substrata. These soils are classified as Andic Cryochrepts, Entic

Cryumbrepts, and Andic Cryaquepts. The dominant potential natural vegetation

is subalpine fir, grand fir and sedge/shrub complexes. This component is 20

percent of the map unit.

Compiled by: Pat Green, Nez Perce National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 422
LTA60-M333D

MOUNTAIN SLOPES AND RIDGES: METASEDIMENTARY (BELT)

Location: This unit is located in the Clark Fork, Coeur d' Alene, St. Joe and

Clearwater River basins of northwest Montana and northern Idaho.

 Acreage by Section

 60-M333D 1,726,317

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a low to mid

elevation, gentle to steep sloping, mountain sideslope and ridge landscape

setting, which is typically composed of dissected and non dissected mountain

slopes, nivational hollows and ridges comprised of colluvium and residuum.

Parent materials are surface volcanic ash overlying weakly to moderately

weathered quartzites, siltites and argillites from Precambrian metasedimentary

bedrock.

Accessory Characteristics: The primary soils are shallow to deep loams and

sandy loams, with a small component of rock outcrop and scree. The vegetation

is a mosaic of coniferous forest. Mean annual precipitation ranges from 64

to 178 centimeters (25 to 70 inches). The elevation range is 758 to 1818

meters (2500 to 6000 feet). The dominant slopes have gradients of 20 to 70

percent. This unit is slightly to strongly dissected by streams, with the

dominant stream pattern being parallel to dendritic. 

LTA Components: This landtype association consists of dissected and

non-dissected mountain slopes, and glacially scoured ridges.

Dissected mountain slopes and nivational hollows occur on moderately steep to

steep slopes, and are formed in metasediments that consist of quartzites,

siltites and argillites. The slope gradients range from 30 to 70 percent.

Soils on these landforms are shallow to deep, weakly to moderately weathered

and medium textured. The major soils on the well drained sites are classified

as Typic Udivitrands, Alfic Udivitrands, Andic Dystrochrepts and Typic

Dystrochrepts, with xeric phases of these on some southerly aspects. Rock

outcrop and scree occupies less than 5 percent of this unit. The dominant

potential natural vegetation on the well drained sites are western redcedar,

western hemlock, grand fir and subalpine fir.

Non-dissected mountain slopes and ridges occur on gentle to moderately steep

slopes and are formed in the same Belt metasedimentary rock types stated in

the landscape component above. The slope gradients range from 10 to 60

percent. Soils on these landforms are shallow to deep, weakly to moderately

weathered and medium textured. The major soils are classified as Typic

Udivitrands, Andic Dystrochrepts and Typic Dystrochrepts. Moderately weathered

soils consist of Alfic Udivitrands and Alfic Vitrixerands. Rock outcrop and

scree occupies from less than 5 up to 10 percent of the area. The dominant

potential natural vegetation is western redcedar, western hemlock, grand fir,

Douglas-fir and subalpine fir.

Glacially scoured ridge tops have been strongly modified by continental ice.

The prominent features are ridge tops and ridge noses with exposed bedrock.

These areas have slopes that range from 10 to 45 percent. Soils on these

landforms are shallow to moderately shallow and consist of rock, sand and

silt. The major soils are classified as Lithic Cryochrepts and Lithic

Dystrochrepts. Rock outcrops occupy more than 50 percent of the area. The

dominant potential natural vegetation is Douglas-fir and subalpine fir.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forests, and Louis

Kuennen, Kootenai National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 423
LTA51-M333D

LTA51-M333A

GLACIATED MOUNTAIN SLOPES: GRANITICS

Location: This unit is located mostly in the Selkirk Mountains of the Priest,

Pend Oreille and Spokane River basins of northwestern Idaho and northeast

Washington.

 Acreage by Section

 51-M333D 3,788

 51-M333A 467,331

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a gentle to

moderately steep valley bottom, mountain sideslope and ridge landscape setting

at elevations that range from low to high. The unit is typically composed of

dissected and non dissected mountain slopes, valleys and ridges comprised of

alpine and continental till. Parent materials are surface volcanic ash

overlying substratum materials of glacial tills derived from Cretaceous

Kaniksu Batholith bedrock.

Accessory Characteristics: The primary soils are shallow to deep sands, with

a small component of rock outcrop and scree. The vegetation is a mosaic of

coniferous forest. Mean annual precipitation ranges from 76 to 178 centimeters

(30 to 70 inches). The elevation range is 800 to 2062 meters (2625 to 6765

feet). The dominant slopes have gradients of 15 to 55 percent. This unit is

slightly to highly dissected by streams, with the dominant stream pattern

being parallel. 

LTA Components: This landtype association consists of dissected and

non-dissected, continentally glaciated, convex ridges and concave valleys.

The glaciated convex ridges and mountain sideslopes were strongly scoured and

then covered by varying thickness of glacial tills. The slope gradients range

from near level to 60 percent. The drainage bottoms and toeslopes consist of

deep glacial tills and glacio-fluvial materials. The slope gradients range from

0 to 40 percent. Soils on the ridge and mountain sideslopes landforms are

shallow to deep, weakly weathered, and sandy textured. Soils in the drainage

bottoms and toeslopes are deep, weakly weathered, and sandy textured. The

major soils on the well drained sites are classified as Andic Cryochrepts and

Andic Dystrochrepts, with Andic Xerochrepts on the drier sites. The areas with

deeper ash caps are Vitric Haplocryands and Typic Udivitrands, Andic

Cryumbrepts and Andic Haplumbrepts occur in the more poorly drained sites.

Rock outcrop and scree occurs as an inclusion in the scoured ridge and

mountain sideslope landforms. The dominant potential natural vegetation on the

well drained, high elevation sites is subalpine fir with western hemlock,

western redcedar, grand fir and Douglas-fir occurring at low to mid

elevations. The dominant potential natural vegetation on the poorly drained

sites is subalpine fir at the higher elevations and cold air pockets at lower

elevations, and western redcedar at the mid and lower elevations.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 424
LTA62 -M333D

MOUNTAIN SLOPES AND RIDGES: WEAKLY WEATHERED GRANITICS

Location: This unit is located in the Coeur d'Alene, St. Joe and Clearwater

Mountains of the Bitterroot range which are part of the Clark Fork, Coeur d'

Alene, St. Joe and Clearwater River basins of northwest Montana and northern

Idaho.

 Acreage by Section

 62-M333D 49,409

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a low to high

elevation, gentle to steep sloping, mountain sideslope and ridge landscape

setting, which is typically composed of dissected and non dissected mountain

slopes, nivational hollows and ridges comprised of colluvium and residuum.

Parent materials are surface volcanic ash of varying depths overlying weakly

weathered granitics of the Idaho Batholith.

Accessory Characteristics: The primary soils are shallow to deep loams and

sandy loams, with a small component of rock outcrop and scree. The vegetation

is a mosaic of coniferous forest. Mean annual precipitation ranges from 64

to 152 centimeters (25 to 60 inches). The elevation range of this unit is 700

to 1615 meters (2300 to 5300 feet). The dominant slopes have gradients of 20

to 70 percent. This unit is slightly to moderately dissected by streams, with

the dominant stream pattern being parallel to dendritic. 

LTA Components: This landtype association consists of dissected and

non-dissected mountain slopes, nivational hollows and ridges.

These dissected and non-dissected mountain slopes and nivational hollows occur

on moderately steep to steep slopes, and are formed in granitics from the

Idaho Batholith. The slope gradients range from 35 to 60 percent. Soils on

these landforms are moderate deep to deep, weakly to moderately weathered and

medium to coarse textured. The major soils on the well drained moist sites are

classified as Typic Udivitrands. The major soils on the well drained, dry

sites are Andic Xerochrepts. Humic Udivitrands occur in the more poorly

drained sites. Rock outcrop and scree occupies less than 5 percent of the

unit. The dominant potential natural vegetation on the well drained, moist

sites are western redcedar, western hemlock and grand fir. The dominant

potential natural vegetation on the well drained, dry sites are grand fir and

Douglas-fir. The dominant potential natural vegetation on the poorly drained

sites are western redcedar.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 425
LTA63-M333D

MOUNTAIN SLOPES AND RIDGES: SCHISTS AND GNEISSES

Location: This unit is located in the Clearwater and Coeur d'Alene Mountains

of Idaho in the Potlatch and much of the North Fork Clearwater River Basins.

 Acreage by Section

 63-M333D 311,815

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a moderately sloping

mountain slope and ridge landscape setting, which is typically composed of

moderately dissected mountain slopes and ridgetops. Parent materials are a

surface layer of Mazama volcanic ash underlain by schist and gneiss with high

amounts of mica.

Accessory Characteristics: The primary soils are moderately deep to very deep

with silt loam to loam surface textures and gravelly loam subsurface layers.

The vegetation is a mosaic of coniferous forest. Mean annual precipitation

ranges from 64 to 127 cms. (25 to 50 inches). The elevation range is 762 to

1829 meters (2500 to 6000 feet). The dominant slopes have gradients of 30 to

60 percent. This unit is moderately to highly dissected by streams, with the

stream pattern being dendritic to trellis. Wetlands and moist seeps are a

common component of this unit.

LTA Components: This landtype association consists of steep mountain slopes

and ridge tops.

Steep mountain slopes are formed in schist and gneiss colluvium overlain by

Mazama volcanic ash. Slope gradients range from 30 to 60 percent. Soils on

these landforms are moderately deep to very deep, highly developed, and

consist of silt loam to loam surface textures with gravelly loam subsurface

textures. These soils are classified as Andic Dystrochrepts, Andic

Xerochrepts, and Vitric Hapludands. Rock outcrop occurs on about 5 percent of

this landscape component. The dominant potential natural vegetation is

western redcedar and grand fir. This component represents 80 percent of this

unit.

Ridgetops are formed in gneiss and schist residuum and colluvium overlain by a

mixed layer of Mazama volcanic ash. Slope gradients range from 15 to 50

percent. Soils on these landforms are shallow to deep, moderately to highly

developed, and consist of silt loam to loam surface textures with gravelly to

cobbly loam subsurface textures. These soils are classified as Andic

Dystrochrepts, Typic Udivitrands, Andic Xerochrepts, and Vitric Hapludands.

Rock outcrop occurs on about 15 percent of this landscape component. The

dominant potential natural vegetation is western redcedar, grand fir, and

Douglas-fir. This component represents 20 percent of this unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 426
LTA64-M333D

MOUNTAIN SLOPES AND RIDGES: VOLCANICS

Location: This unit is located along streams and rivers, on the western edge

of the Coeur d' Alene and St. Joe river basins of northern Idaho.

 Acreage by Section

 64-M333D 123,010

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA consists of plateaus, mountain

slopes, canyon walls and footslopes at generally low elevations. Parent

materials are surface volcanic ash overlying poorly to moderately weathered

Columbia River basalt.

Accessory Characteristics: The primary soils are moderately deep, stony loams

and stony silt loams. The vegetation is a mosaic of coniferous forest. Mean

annual precipitation ranges from 64 to 79 centimeters (25 to 30 inches). The

elevation range of this unit is 640 to 975 meters (2100 to 3200 feet). The

dominant slopes have gradients of 15 to 55 percent. This unit is moderately

dissected by streams, with the dominant stream pattern being parallel.

LTA Components: This landtype association consists of plateaus, mountain

slopes, footslopes and canyon walls.

The plateaus, mountain slopes and footslopes are formed in mixed volcanic ash

influenced loess overlying residuum and colluvium of basalt. Slope gradients

range from 15 to 50 percent and the steeper canyon walls range from 50 to 65+

percent. Soils on these landforms are generally moderately deep, weakly to

moderately weathered, and medium textured. These soils are classified asTypic

Udivitrands, Typic Xerochrepts and Ultic Argixerolls. The dominant potential

natural vegetation is grand fir on the well drained sites. Western redcedar

will occur in the draws and on some north aspects at the higher elevation with

deeper soils. Douglas-fir and ponderosa pine occur on the drier sites.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 427
LTA66-M333D

LTA66-M333A

MOUNTAIN SLOPES AND RIDGES: CARBONATES

Location: This LTA is located adjacent to Lake Pend Oreille in the Coeur

d'Alene Mountains on the Idaho Panhandle National Forests.

 Acreage by Section

 66-M333D 594

 66-M333A 513

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountain landscape

setting, which is typically composed of stream dissected mountain slopes.

Parent materials are Mazama volcanic ash over weakly weathered limestone

bedrock associated with the Cambrian aged Lakeview formation. Small areas of

Rennie shale and Gold Creek quartzite occur with the Lakeview limestone.

Accessory Characteristics: The primary soils are moderately deep to deep.

They have silt loam surface soils overlying very gravelly to very cobbly sandy

loam to loam subsoils. The vegetation is a coniferous forest. Mean annual

precipitation ranges from 75 to 88 centimeters (30 to 35 inches). The

elevation range of this LTA is 616 to 1280 meters (2000 to 4200 feet). The

dominant slopes have gradients of 10 to 50 percent. This LTA is moderately

dissected by streams with the dominant stream pattern being parallel.

LTA Components: This landtype association consists of mountain slopes.

Mountain slopes are formed in limestone bedrock. Slope gradients range from 10

to 50 percent. Soils on these landforms are moderately deep to deep, and well

drained. They have a silt loam or loam surface layer underlain by very

gravelly to very cobbly sandy loam and loam subsurface layers. These soils are

classified as Andic Dystrochrepts and Typic Udivitrands. Rock outcrop occurs

on about 10 percent of this landscape component. The dominant potential

natural vegetation is Douglas-fir, grand fir, western redcedar and western

hemlock series. This component represents 100 percent of this LTA.

Compiled by: Gary Ford, Regional Office

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 428
LTA67-M333D

MOUNTAIN SLOPES AND RIDGES: QUARTZITES

Location: This unit is located in the Clearwater Mountains of Idaho in the

upper North Fork Clearwater River Basin.

 Acreage by Section

 67-M333D 7,073

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a moderately sloping

mountain slope and ridge landscape setting, which is typically composed of

moderately dissected mountain slopes and ridgetops. Parent materials are a

surface layer of Mazama volcanic ash underlain by highly weathered Revett

quartzites .

Accessory Characteristics: The primary soils are moderately deep to very deep

with silt loam to loam surface textures and gravelly loam subsurface layers.

The vegetation is a mosaic of coniferous forest. Mean annual precipitation

ranges from 152 to 178 cms. (60 to 70 inches). The elevation range is 1067 to

1676 meters (3500 to 5500 feet). The dominant slopes have gradients of 30 to

60 percent. This unit is moderately to highly dissected by streams, with the

stream pattern being dendritic to trellis. Wetlands and moist seeps are a

common component of this unit.

LTA Components: This landtype association consists of steep mountain slopes

and ridge tops.

Steep mountain slopes are formed in Revett quartzite colluvium overlain by

Mazama volcanic ash. Slope gradients range from 30 to 60 percent. Soils on

these landforms are deep to very deep, highly developed, and consist of silt

loam to loam surface textures with gravelly loam subsurface textures. These

soils are classified as Andic Dystrochrepts, Andic Xerochrepts, and Vitric

Hapludands. Rock outcrop occurs on about 5 percent of this landscape

component. The dominant potential natural vegetation is western redcedar and

grand fir. This component represents 80 percent of this unit.

Ridgetops are formed in Revett quartzite residuum and colluvium overlain by a

mixed layer of Mazama volcanic ash. Slope gradients range from 15 to 50

percent. Soils on these landforms are moderate to deep, moderately to highly

developed, and consist of silt loam to loam surface textures with gravelly to

cobbly loam subsurface textures. These soils are classified as Andic

Dystrochrepts, Andic Xerochrepts, and Vitric Hapludands. Rock outcrop occurs

on about 15 percent of this landscape component. The dominant potential

natural vegetation is western redcedar and grand fir. This component

represents 20 percent of this unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 429
LTA68-M333D

LTA68-M333B

LTA68-M333C

MOUNTAIN SLOPES AND RIDGES: SANDSTONES, SHALES, AND CARBONATES

Location: This unit is located in the Whitefish, Swan, and Flathead mountain

ranges of the Flathead, Clearwater, and Blackfoot River basins in northwest

Montana.

 Acreage by Section

 68-M333D 1,511

 68-M333B 8,043

 68-M333C 36,067

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in both upland and

alpine landscape settings, which are typically composed of dissected mountain

slopes, glaciated mountain slopes, and glacially scoured ridge top landforms.

Colluvial, fluvial and glacial, erosional/depositional geomorphic processes

occur in these areas. Parent materials are volcanic ash overlying weakly

weathered Paleozoic and Mesozoic sandstone, shale, and limestone bedrock.

Accessory Characteristics: The primary soils are shallow to moderately deep

with very gravelly medium and moderately fine textures. The vegetation is a

mosaic of coniferous forest, mountain shrubland, and mountain grassland. Mean

annual precipitation ranges from 51 to 177 centimeters (20 to 70 inches). The

elevation range is 1,219 to 2,134 meters (4000 to 7000 feet). The dominant

slopes have gradients of 55 to 70 percent. This unit is moderate to strongly

dissected by streams with the dominant stream patterns being dendritic and

sub-parallel.

LTA Components: This landtype association has glacially scoured ridge tops

and dissected mountain slopes (fluvial) with inclusions of glaciated mountain

slopes landform components.

Glacially scoured ridge tops have been strongly modified by continental ice.

The prominent features are ridge tops and ridge noses with exposed bedrock.

These areas have slopes that range from 10 to 45 percent. Soils on these

landforms are shallow to moderately deep, weak to moderately developed with

medium and moderately fine textures. The major soils are classified as Lithic,

Andic, or Typic Cryochrepts. Rock outcrops occupy more than 50 percent of the

area. The dominant potential natural vegetation is subalpine fir-whitebark

pine, and subalpine fir. This landform component makes up 40 percent of the

LTA.

The dissected mountain slopes (fluvial) landscape is one that is

weathering-in-place. It is chemical weathering further affected by colluvial

action. Slope gradients range from 30 to 60 percent. Soils on these landforms

are moderately deep to deep, weak to moderate development, with medium and

moderately fine textures. The major soils are classified as Andic Cryochrepts,

Andeptic and Typic Cryoboralfs, and Typic or Argic Cryoborolls. Rock outcrops

occupy less than 10 percent of the area. The dominant potential natural

vegetation is Douglas-fir and subalpine fir. This landform component

represents 60 percent of the LTA.

Compiled by: Dean Sirucek, Flathead National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 430
LTA70-M333D

LTA70-M333B

LTA70-M333C

FROST SHATTERED MOUNTAIN RIDGE TOPS: METASEDIMENTARY (BELT)

Location: This unit is located in the Whitefish, Cabinets, Purcell, Salish,

Bitterroot, Swan, Mission, Coeur d'Alene, St. Joe, Clearwater, and Flathead

Mountain ranges. These occur in the Clark Fork, Coeur d'Alene, St. Joe,

Clearwater, Kootenai, and Flathead River basins in northwest Montana and north

Idaho.

 Acreage by Section

 70-M333D 518,308

 70-M333B 153,508

 70-M333C 60,686

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a alpine landscape

setting which is typically composed of a ridge top landform. Parent materials

are volcanic ash overlying weakly weathered, moderately-metamorphosed

Proterozoic metasedimentary bedrock composed of argillites, siltites,

quartzites, dolomites, and limestones. There are inclusions of other bedrocks,

such as granite, in this map unit.

Accessory Characteristics: The primary soils are shallow to moderately deep

with very gravelly medium textures. The vegetation is a mosaic of coniferous

forest, mountain shrubland, and mountain grasslands. Mean annual precipitation

ranges from 102 to 279 centimeters (40 to 110 inches). The elevation range is

1,341 to 2,758 meters (4400 to 9100 feet). The dominant slopes have gradients

of 10 to 55 percent. This map unit is undivided to slightly dissected by

streams, with the pattern being dendritic or parallel where present.

LTA Components: This landtype association consists of glacially scoured,

frost shattered ridge tops.

Glacially scoured, frost shattered ridge tops have been strongly modified

continental ice, alpine ice, and frost action, and are formed in

metasedimentary rocks. The prominent features are ridge tops that have been

rounded or scoured by the previously mentioned actions. Exposed bedrock

comprises 10 to 40 percent of the area. These areas have slopes that range

from 10 to 60 percent. Soils on these landforms are shallow to moderately deep

and weakly developed with very gravelly medium textures. The major soils are

classified as Lithic Cryochrepts, Andic Cryochrepts and Vitric Haplocryands.

The dominant potential natural vegetation is subalpine fir, mountain hemlock,

and whitebark pine-subalpine fir. This landform component makes up 90 percent

of the map unit. There are up to 10 percent inclusions of nivational hollows

that occur in this map unit.

Compiled by: Dean Sirucek, Flathead National Forest; Louis Kuennen, Kootenai

National Forest; Skip Barndt, Lolo National Forest and Jerry Niehoff, Idaho

Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 431
LTA71-M333D

FROST SHATTERED MOUNTAIN RIDGETOPS: HIGHLY WEATHERED GRANITICS

Location: This unit is located in the Clearwater Mountains in Idaho,

occurring extensively throughout the Lochsa and North Fork Clearwater River

Basins.

 Acreage by Section

 71-M333D 181,557

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a high elevation

mountain ridge landscape setting which is typically composed of frost

shattered ridgetops and mountain slopes. Parent materials are a highly mixed

surface layer of Mazama volcanic ash, colluvium, and residuum underlain by

highly weathered granitics of the Idaho Batholith.

Accessory Characteristics: The primary soils are moderately deep to deep with

loamy to sandy loam surface textures and gravelly loam and sandy subsurface

textures. The vegetation is a mosaic of coniferous forest. Mean annual

precipitation ranges from 89 to 203 cms. (35 to 80 inches). The elevation

range is 1372 to 2438 meters (4500 to 8000 feet). The dominant slopes have

gradients of 20 to 55 percent. This unit is slightly dissected by streams,

with the dominant stream pattern being dendritic. Wetlands are a minor

component of this unit.

LTA Components: This landtype association consists of frost shattered

mountain slopes and ridgetops.

Frost shattered mountain slopes are formed in colluvium of highly weathered

Idaho Batholith granitics overlain by a variable thickness of Mazama volcanic

ash. Slope gradients range from 30 to 55 percent. Soils on these landforms

are moderately deep, weakly developed, and consist of loam to sandy loam

surface textures with very gravelly, loamy sand or sandy loam subsurface

textures. These soils are classified as Andic Cryochrepts, Dystric

Cryochrepts, and Typic Haplocryands. Rock outcrop occurs on about 10 percent

of this landscape component. The dominant potential natural vegetation is

subalpine fire and whitebark pine. This component represents 75 percent of

this unit.

Frost shattered ridgetops are formed in residuum and colluvium of highly

weathered Idaho Batholith granitics overlain by a variable thickness of Mazama

volcanic ash. Slope gradients range from 20 to 40 percent. Soils on these

landforms are moderately deep, weakly developed, and consist of loam to sandy

loam surface textures with very gravelly, loamy sand or sandy loam subsurface

textures. These soils are classified as Andic Cryochrepts, Dystric

Cryochrepts, and Typic Cryochrepts. Rock outcrop occurs on about 20 percent of

this landscape component. The dominant potential natural vegetation is

subalpine fir and whitebark pine. This component represents 20 percent of this

unit.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 432
LTA72-M333D

LTA72-M333A

LTA72-M333B

FROST SHATTERED MOUNTAIN RIDGE TOPS: WEAKLY WEATHERED GRANITICS

Location: This unit is located in the Selkirk, Purcell and Cabinet Mountains

of the Priest, Kootenai, Pack River and Clark Fork River basins of northeast

Idaho and northwest Montana. This unit is also located in the St. Joe

Mountains of the Bitterroot Range, which is part of the St. Joe and Little

North Fork of the Clearwater River basins of northern Idaho.

 Acreage by Section

 72-M333D 17,671

 72-M333A 4,337

 72-M333B 967

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a high elevation,

gentle to moderately steep sloping, mountain sideslope and ridge landscape

setting, which is typically composed of weakly to non dissected mountain

slopes, and associated ridges comprised of colluvium and residuum. Parent

materials are surface volcanic ash overlying weakly weatheredgranitics from

Cretaceous Kaniksu Batholith and Idaho Batholith.

Accessory Characteristics: The primary soils are shallow to deep sands, sandy

loams and loams, with up to 30 percent rock outcrop and scree on some units.

The vegetation is a mosaic of coniferous forest. Mean annual precipitation

ranges from 114 to 178 centimeters (45 to 70 inches). The elevation range of

this unit is 1433 to 1981 meters (4700 to 6500 feet). The dominant slopes have

gradients of 20 to 55 percent. This unit is weakly to non-dissected by

streams, with the dominant stream pattern being parallel when they occur.

LTA Components: This landtype association consists of weakly to non-dissected

mountain slopes and associated ridges.

Weakly to non-dissected mountain slopes and ridges occur on gentle to

moderately steep slopes and are formed in batholith that consists of granite,

granodiorite or other rocks of similar composition. The slope gradients range

from 10 to 60 percent. Soils on these landforms are shallow to deep, weakly

weathered and coarse to medium textured. The major soils are classified as

Vitric Haplocryands and Andic Cryochrepts. These soils make up the majority of

the unit and occur on the well drained sites. Vitric Fulvicryands and Andic

Cryumbrepts occur in the poorly drained sites. The shallow soils are

classified as Lithic Haplocryands and Lithic Cryochrepts. The dominant

potential natural vegetation series over most of the area is subalpine fir,

but mountain hemlock is dominant in the St. Joe and Little North Fork of the

Clearwater River basins. Minor Douglas-fir occurs on the very dry sites.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 433
LTA80-M333D

LOW RELIEF HILLS: METASEDIMENTARY (BELT)

Location: This unit is located in the St Joe and Clearwater Mountains of the

Bitterroot range, which are part of the St. Joe and Clearwater River basins of

northwest Montana and northern Idaho.

 Acreage by Section

 80-M333D 122,360

LTA Setting and General Characteristics

Differentiating characteristics: This map unit occurs in a low to mid

elevation, gentle to moderately sloping, mountain sideslope and ridge

landscape setting, which is composed of highly dissected mountain slopes and

associated ridges comprised deeply weathered residuum. Parent materials are

surface volcanic ash overlying moderately to highly weathered quartzites, and

siltites from Precambrian metasedimentary bedrock.

Accessory Characteristics: The primary soils are deep sandy loams, loams and

clay loams. The vegetation is a mosaic of coniferous forest. Mean annual

precipitation ranges from 89 to 152 centimeters (35 to 60 inches). The

elevation range of this unit is 655 to 1524 meters (2150 to 5000 feet). The

dominant slopes have gradients of 20 to 60 percent. This unit is highly

dissected, but many of the dissections do not have live stream channels. The

stream pattern is strongly dendritic.

LTA Components: This landtype association consists of highly dissected

mountain slopes and associated ridges.

Highly dissected mountain slopes and associated ridges occur on gentle to

moderately steep slopes and are formed in metasediments that consist of

quartzites, siltites and inclusions of schists. The slope gradients range from

10 to 60 percent. Soils on these landforms are deep, moderately to highly

weathered and medium textured. The major soils on the well drained sites are

classified as Typic Udivitrands and Alfic Udivitrands. Humic Udivitrands occur

in the more poorly drained sites. The dominant potential natural vegetation on

the well drained sites are western redcedar, western hemlock, and grand fir.

The dominant potential natural vegetation on the poorly drained sites is

western redcedar.

Compiled by: Jerry Niehoff, Idaho Panhandle National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 434
LTA81-M333D

LOW RELIEF HILLS: HIGHLY WEATHERED GRANITICS

Location: This unit is located in the Clearwater Mountains of Idaho in the

St. Maries, St. Joe, Lochsa, and North Fork Clearwater River Basins.

 Acreage by Section

 81-M333D 270,383

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a low to mid

elevation, gently to moderately sloping landscape setting which is typically

composed of low relief rolling hills and low mountains. Parent materials are

Mazama volcanic ash underlain by highly weathered granitics of the Idaho

Batholith.

Accessory Characteristics: The primary soils are deep to very deep with silt

loam and loam surface textures and loam to gravelly loam subsurface textures.

The vegetation is a mosaic of coniferous forest. Mean annual precipitation

ranges from 76 to 127 cms.(30 to 50 inches). The elevation range is 610 to

1524 meters (2000 to 5000 feet). The dominant slopes have gradients of 5 to 30

percent. This unit is highly dissected by streams, with the dominant stream

pattern being dendritic. Wetlands are a minor component of this unit.

LTA Components: This landtype association consists of low relief rolling

hills.

Low relief rolling hills are formed in highly weathered granitic residuum

overlain by Mazama volcanic ash. Slope gradients range from 5 to 30 percent.

Soils on these landforms are deep to very deep, highly developed, and consist

of silt loam and loam surface textures and loam to gravelly loam subsurface

textures. These soils are classified as Typic Udivitrands, Alfic Udivitrands,

and Vitric Hapludands. Rock outcrop is uncommon in this landscape component.

The dominant potential natural vegetation is western redcedar, grand fir, and

western hemlock.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 435
LTA82-M333D

LOW RELIEF HILLS: VOLCANICS

Location: This unit is located in west-central Idaho in the Potlatch and

North Fork Clearwater River Basins.

 Acreage by Section

 82-M333D 43,729

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a low to mid

elevation, gently to moderately sloping landscape setting which is typically

composed of low relief rolling hills and low mountains. Parent materials are

wind-blown loess and Mazama volcanic ash underlain by Columbia flood basalts.

Accessory Characteristics: The primary soils are deep to very deep with silt

loam and loam surface textures and gravelly silt loam to silty clay

subsurface textures. The vegetation is a mosaic of coniferous forest. Mean

annual precipitation ranges from 64 to 114 cms. (25 to 45 inches). The

elevation range is 762 to 1219 meters (2500 to 4000 feet). The dominant

slopes have gradients of 5 to 30 percent. This unit is highly dissected by

streams, with the dominant stream pattern being dendritic. Wetlands are a

minor component of this unit.

LTA Components: This landtype association consists of low relief rolling

hills.

Low relief rolling hills are formed in Columbia flood basalt residuum

overlain by wind-blown loess and Mazama volcanic ash. Slope gradients range

from 5 to 30 percent. Soils on these landforms are deep to very deep, highly

developed, and consist of silt loam and loam surface textures and silt loam

to gravelly silt loam and silty clay subsurface textures. These soils are

classified as Ultic Argixerolls, Ultic Haploxeralfs, and Andic Xerochrepts. 

Rock outcrop are uncommon on this landscape component. The dominant potential

natural vegetation is grand fir, Douglas-fir, and western redcedar.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 436
LTA83-M333D

LOW RELIEF HILLS: FINE TERTIARY SEDIMENTS

Location: This unit is located in west-central Idaho in the St. Maries,

Palouse, and North Fork Clearwater River Basins.

 Acreage by Section

 83-M333D 292,046

LTA Setting and General Characteristics

Differentiating characteristics: This LTA occurs in a low to mid elevation,

gently to moderately sloping landscape setting which is typically composed of

low relief rolling hills and low mountains. Parent materials are Mazama

volcanic ash and wind-blown loess underlain by Tertiary alluvial deposits.

Accessory Characteristics: The primary soils are deep to very deep with silt

loam surface textures and silt loam to silty clay subsurface textures. The

vegetation is a mosaic of coniferous forest. Mean annual precipitation ranges

from 76 to 127 cms. (30 to 50 inches). The elevation range is 762 to 1372

meters (2500 to 4500 feet). The dominant slopes have gradients of 5 to 30

percent. This unit is highly dissected by streams, with the dominant stream

pattern being dendritic. Wetlands are a minor component of this unit.

LTA Components: This landtype association consists of low relief rolling

hills.

Low relief rolling hills are formed in Tertiary alluvium overlain by Mazama

volcanic ash and wind-blown loess. Slope gradients range from 5 to 30

percent. Soils on these landforms are deep to very deep, highly developed,

and consist of silt loam surface textures and silt loam to silty clay

subsurface textures. These soils are classified as Alfic Udivitrands, Typic

Udivitrands, Ultic Haploxeralfs, Typic Eutroboralfs, and Eutric

Glossoboralfs. Rock outcrops are uncommon on this landscape component. The

dominant potential natural vegetation is western redcedar and grand fir.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 437
LTA84-M333D

LOW RELIEF HILLS: HIGHLY WEATHERED SCHISTS

Location: This unit is located in west-central Idaho in the Potlatch, Marble

Creek, St. Maries Creek, and North Fork Clearwater River Basins.

 Acreage by Section

 84-M333D 294,317

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a low to mid

elevation, gently to moderately sloping landscape setting which is typically

composed of low relief rolling hills and low mountains. Parent materials are

Mazama volcanic ash underlain by highly weathered schists.

Accessory Characteristics: The primary soils are deep to very deep with silt

loam surface textures and silt loam to silty clay loam subsurface textures.

The vegetation is a mosaic of coniferous forest. Mean annual precipitation

ranges from 64 to 114 cms. (25 to 45 inches). The elevation range is 762 to

1524 meters (2500 to 5000 feet). The dominant slopes have gradients of 5 to

30 percent. This unit is highly dissected by streams, with the dominant

stream pattern being dendritic. Wetlands are a minor component of this unit.

LTA Components: This landtype association consists of low relief rolling

hills.

Low relief rolling hills are formed in highly weathered schists overlain by

Mazama volcanic ash. Slope gradients range from 5 to 30 percent. Soils on

these landforms are deep to very deep, highly developed, and consist of silt

loam surface textures and silt loam to silty clay loam subsurface textures.

These soils are classified as Typic Udivitrands, Typic Hapludands, and Vitric

Hapludands. Rock outcrops are uncommon on this landscape component. The

dominant potential natural vegetation is western redcedar and grand fir.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 438
LTA85-M333D

LOW RELIEF HILLS: MODERATELY WEATHERED GNEISSES, QUARTZITES AND SCHISTS

Location: This unit is located at middle elevations in north central Idaho in

the Clearwater River Basins.

 Acreage by Section

 85-M333D 19,796

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is rolling uplands developed

in volcanic ash over moderately weathered residuum of gneiss, schist, and

quartzite associated with the Idaho batholith.

Accessory Characteristics: The primary soils are deep to very deep silt

loams. The vegetation is dominantly coniferous forest. Mean annual

precipitation ranges from 102 to 152 centimeters (40 to 60 inches). The

elevation range is 1373 to 1983 meters (4500 to 6500 feet). The dominant

slopes have gradients of 10 to 40 percent. This unit is moderatelyto highly

dissected by streams, with the dominant stream pattern being dendritic.

Wetlands are a minor component of this map unit.

LTA Components: This landtype association consists of rolling hills.

Rolling hills are formed in volcanic ash over quartzite, gneiss, and schist

residuum. Soils on these landforms are very deep, moderately developed silt

loams with gravelly sandy loam substrata. These soils are classified as Andic

Dystrochrepts, Typic Udivitrands, and Vitric Hapludands. Rock outcrop is less

than 10 percent of the unit. The dominant potential natural vegetation at mid

elevations is grand fir series, and at upper elevations subalpine fir series.

Western red cedar and alder communities in moist openings are common near the

north part of the Clearwater River basin.

Compiled by: Pat Green, Nez Perce National Forest, and Jim Mital, Clearwater

National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 439
LTA90-M333D

MASS WASTED SLOPES: MIXED GEOLOGY

Location: This unit is located in west-central Idaho in the North Fork

Clearwater and St. Maries River Basins.

 Acreage by Section

 90-M333D 16,505

LTA Setting and General Characteristics

Differentiating characteristics: This map unit is mass wasted slopes. 

Parent materials are can be of any lithology, but in this section they are

dominantly gneisses and schists overlain with a variable thickness of Mazama

volcanic ash.

Accessory Characteristics: The primary soils are deep to very deep silt loams

to cobbly loams. The vegetation is a mosaic of coniferous forest. Mean annual

precipitation ranges from 51 to 102 cms. (20 to 40 inches). The elevation

range is 457 to 1372 meters (1500 to 4500 feet). The dominant slopes have

gradients of 30 to 80 percent. This unit is moderately dissected by streams,

with the dominant stream pattern being parallel to dendritic. Wetlands are a

minor component of this unit, but moist seeps can be locally common.

LTA Components: This landtype association consists of mass wasted slopes.

Mass wasted slopes are formed in Mazama volcanic ash overlying primarily

gneisses and schists. Slope gradients range from 30 to 80 percent. Soils on

these landforms are deep to very deep, weakly to moderately developed loams

to cobbly loams. Soil classification is highly variable but many are

classified as Andic Dystrocrepts and Vitrandic Dystrochrepts. Rock outcrops

occur on less than 10 percent of this unit. The dominant potential natural

vegetation is grand fir, western redcedar, and Douglas-fir.

Compiled by: Jim Mital, Clearwater National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 440
CHAPTER 15

LTA Descriptions

Section 251A Red River Valley

Section 251B North Central Glaciated Plains

Section 331D Northwestern Glaciated Plains

Section 331F Northwestern Great Plains

Section 331G Powder River Basin

Section 342A Bighorn Basin

Section M331B Big Horn Mountains

This chapter contains map unit descriptions for those landtype associations

which occur in Sections with limited amounts of Forest Service Ownership.

Due to the limited extent of LTA occurrence within these Sections, the

detailed analysis of LTAs included in other chapters is not warranted here.

There are four general areas covered in this chapter: the Highwood

Mountains of the Lewis and Clark National Forest (portions of Section 331D);

the Sheyenne National Grasslands (portions of Sections 251A); the Bighorn

Mountains (portions of Section M331B, including a small portion of the

adjacent Bighorn Basin); and the remaining portions of the Custer National

Forest in eastern Montana and North Dakota (portions of Section 331F and

331G). Map unit descriptions are preceded by the following illustrations:

 Figure 65: 251A landscape photograph

 Sheyenne National Grassland, Custer National Forest

 

 Figure 66: Bar chart showing abundance of landform groups within 251A

 Figure 67: Bar chart showing abundance of geologic material groups

 within 251A

 Figure 68: Bar chart showing abundance of landform groups within 251B

 

 Figure 69: Map showing location of Great Plains minor units.

 Figure 70: Bar chart showing abundance of geologic material

 groups within 251B

 Figure 71: Map showing location of 331D within the Northern Region

 Figure 72: Bar chart showing abundance of landform groups within

 331D

 Figure 73: Bar chart showing abundance of geologic material groups

 within 331D

 Figure 74: Map showing location of 331F within the Northern Region

 Figure 75: Landscape photograph, Section 331F

 Custer National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 441
 Figure 76: Bar chart showing abundance of landform groups

 within 331F

 Figure 77: Bar chart showing abundance of geologic material groups

 within 331F

 Figure 78: Map showing location of 331G within the Northern Region

 Figure 79: Landscape photograph 331G, Custer National Forest

 Figure 80: Bar chart showing abundance of landform groups within 331G

 Figure 81: Bar chart showing abundance of geologic material groups

 within 331G

 Figure 82: Map showing location of M331B within the Northern Region

 Figure 86: Landscape photograph Section M331B, Custer National Forest

 Figure 87: Bar chart showing abundance of landform groups within M331B

 

 Figure 88: Bar chart showing abundance of geologic material groups

 within M331B 

 Figure 89: Map showing location of 342A within the Northern Region

 Figure 90: Bar chart showing abundance of landform groups within 342A

 Figure 91: Bar chart showing abundance of geologic material within 342A

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 442
 SHEYENNE NATIONAL GRASSLANDS

SECTION 251A RED RIVER VALLEY

This Section occurs in the eastern most portion of North Dakota and western

most portion of Minnesota and includes a portion of the Sheyenne National

Grassland. This Section consists of the southern extension of a large, level

lacustrine plain, Glacial Lake Agassiz, that extends far to the north and

west. The plain is dissected by the Red River valley. Pleistocene till and

lacustrine sand-silt-clay-peat-muck cover the bedrock to a depth of 200 to 400

feet. Quaternary alluvium covers the lacustrine sediments in the fans and

major river valleys. Bedrock is predominantly Archean granite, metasediments,

and greenstone; Cretaceous shale and minor Jurassic sandstone overlap the

Archean on the western and southern margins.

LTA8-251A

GLACIOLACUSTRINE PLAINS: DELTAIC SEDIMENTS

Location: This unit is located in eastern North Dakota on the Custer National

Forest.

 Acreage by Section

 251A 44,171

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a flat glacial lake

deltaic lake plain landscape setting, which is typically composed of nearly

level lake sediments. Parent materials are medium textured glacially derived

lacustrine and eolian deposits underlain by thick sequence of glacial till.

Accessory Characteristics: The primary soils are deep, with coarse to

moderately fine textures. The vegetation is a mosaic of cropland and prairie

grasslands. Mean annual precipitation is about 53 cms. (21 inches). The

elevation ranges from 300 to 335 meters (980 to 1100 feet). The dominant

slopes have gradients of 0 to 3 percent. This unit is slightly dissected by

streams, with the dominant stream pattern being dendritic. Wetlands are a

minor component of this unit.

LTA Components: This landtype association consists of nearly level deltaic

plains.

Deltaic plains are formed in lacustrine and eolian deposits. Slope gradients

range from 0 to 3 percent. Soils on these landforms are deep, moderately to

strongly developed, with coarse to moderately fine textures. These soils are

classified as Pachic Udic Haploborolls, Typic Haplaquolls, Typic Calciaquolls,

and Typic Natraquolls. The dominant potential natural vegetation is big

bluestem and wooly sedge. This component represents 100 percent of this unit.

Compiled by: John R. Lane, Custer National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 443
LTA9-251A

GLACI0-LACUSTRINE PLAINS: SANDHILLS AND SAND DUNES

Location: This unit is located in eastern North Dakota on the Custer National

Forest.

 Acreage by Section

 9-251A 73,167

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a flat glacial lake

deltaic plain landscape setting, which is typically composed of dunes,

hummocks and swales. Parent materials are glacially derived eolian underlain

by thick sequence of glacial till.

Accessory Characteristics: The primary soils are deep, with coarse textures.

The vegetation is a mosaic of prairie grasslands. Mean annual precipitation is

about 53 cms (21 inches). The elevation range is 300 to 340 meters (980 to

1120 feet). The dominant slopes have gradients of 0 to 20 percent. This unit

is slightly dissected by streams, with the dominant stream pattern being

dendritic and unintegrated. Wetlands are a major component of this unit.

LTA Components: This landtype association consists of dunes, hummocks and

swales.

Dunes are formed in eolian deposits. Slope gradients range from 0 to 20

percent. Soils on these landforms are deep, poorly developed and have coarse

textures. These soils are classified as stable dunes and Typic Udipsamments.

The dominant potential natural vegetation includes hairy grama, needle and

thread, sand bluestem, bur oak and aspen. This component represents 40 percent

of this unit.

Hummocks are formed in eolian deposits. Slope gradients range from 0 to 10

percent. Soils on these landforms are deep, poorly developed, and have coarse

textures. These soils are classified as Typic Udipsamments, Udic Haploborolls,

and Udorthentic Haploborolls. The dominant potential natural vegetation

includes big bluestem, and needle and thread. This component represents 30

percent of this unit.

Swales are formed in eolian deposits. Slope gradients range from 0 to 20

percent. Soils on these landforms are deep, poorly developed and have coarse

textures. These soils are classified as Typic Udipsamments. The dominant

potential natural vegetation includes wooly sedge in the deeper depressions

and big bluestem on more xeric positions. This component represents 30 percent

of this unit.

Compiled by: John R. Lane, Custer National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 444
LTA13-251A

VALLEYS: FINE GLACIAL SEDIMENTS

Location: This unit is located in the Sheyenne River Valley in southeastern

North Dakota on the Custer National Forest.

 Acreage by Section

 13-251A 13,659

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a flat glacial lake

deltaic plain landscape setting, which is typically composed of stream bottoms

and terraces. Parent materials are alluvium derived from glacial till

underlain by deeper glacial outwash materials.

Accessory Characteristics: The primary soils are deep, with medium and

moderately fine textures. The vegetation is a mosaic of deciduous forest and

cropland. Mean annual precipitation is about 53 cms. (21 inches). The

elevation range is 290 to 325 meters (950 to 1100 feet). The dominant slopes

have gradients of 0 to 4 percent. This unit is slightly dissected by streams

or drainages, with the dominant stream pattern being dendritic. Wetlands are a

major component of this unit.

LTA Components: This landtype association consists of stream bottoms and

terraces.

Stream bottoms are formed in fine alluvium. Slope gradients range from 0 to 4

percent. Soils on these landforms are deep, poorly to strongly developed, with

medium to moderately fine textures. These soils are classified asMollic

Udifluvents, and Cumulic Udic Haploborolls. The dominant potential natural

vegetation includes basswood and green ash. This component represents 70

percent of this unit.

Terraces are formed in fine alluvium. Slope gradients range from 0 to 6

percent. Soils on these landforms are deep, strongly developed, with medium to

fine textures. These soils are classified as Cumulic Udic Haploborolls, and

Udertic Haploborolls. The dominant potential natural vegetation includes bur

oak, green ash and basswood. This component represents 30 percent of this

unit.

Compiled by: John R. Lane, Custer National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 445
SECTION 331D NORTHWESTERN GLACIATED PLAINS

This Section occurs in north central and north east Montana. It consists of

level to gently rolling continental glacial till plains and rolling hills on

the Missouri Plateau. The glacial till is underlain by soft Cretaceous marine

shale.

LTA10-331D

LTA10-M332D

LTA10-M332C

VALLEYS: RECENT COARSE ALLUVIUM

Location: This LTA is located in all mountain ranges of the Lewis and Clark

and Helena National Forests.

 Acreage by Section

 10-331D 982

 10-M332D 86,889

 10-M332C 17,094

LTA Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a valley bottom landscape

setting which is usually composed of stream terraces, floodplains, and

alluvial fans. Parent materials are stratified alluvial deposits of sands,

silts and gravels.

Accessory Characteristics: The primary soils are deep gravelly to extremely

gravelly sandy loams and loams. The vegetation is a mosaic of deciduous

forest, coniferous forest, well drained grassland and wet meadow. Mean annual

precipitation ranges from 38 to 75 centimeters (15 to 30 inches). The

elevation range of this LTA is 1159 to 1983 meters (3800 to 6500 feet). The

dominant slopes are 0 to 4 percent. This LTA by nature has very high stream

densities. Wetlands are an important component of this LTA.

LTA Components: This landtype association consists of floodplains, and stream

terraces/and alluvial fans.

Floodplains and lower terraces are formed in a variety of stratified alluvium.

These floodplains have slope gradients that range from 0 to 2 percent. Soils

on these landforms are very deep, poorly developed, and consist mainly of

sand, gravel and cobble. Silts and clays are found to a lesser extent in oxbow

positions and areas historically occupied by beaver dams. The major soils are

highly variable and include Fluvents, Aquepts, Aquepts, Aquolls and Borolls.

The dominant potential natural vegetation is Englemann spruce and subalpine

fir series, with inclusions of black cottonwood. This component represents 60

percent of this LTA.

Higher terraces and included fans are formed in alluvium. These terraces have

slope gradients that range from 0 to 4 percent. The alluvial fans often have

slope gradients of 8 to 25 percent. Soils on these landforms are deep, poorly

to well developed, and consist mainly of gravelly to extremely gravelly sandy

loams and loams. Sand, gravel and/or cobble layers or lenses are often

present. Areas of silt and clay are present in old oxbow and beaver dam

locations as well as glacial ice dams. The major soils are classified as

Haploborolls and Cryoborolls. The dominant potential natural vegetation is

Douglas-fir, rough fescue, and big sagebrush series. This component represents

40 percent of this LTA.

Compiled by: Richard Saunders, Lewis and Clark National Forest

Revised by Larry Laing, Helena and Lewis and Clark National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 446
LTA27-331D

LTA27-M333C

LTA27-M332C

BREAKS: CARBONATES

Location: This LTA is located in the Big Belt, Little Belt, and Snowy

Mountains in the Missouri River Basin.

 Acreage by Section

 27-331D 148

 27-M333C 459

 27-M332C 97,585

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a very steep, deeply

eroded or faulted mountainous landscape setting, which is typically composed

of structural breaks. Parent materials are colluvium and residuum underlain by

limestone.

Accessory Characteristics: The primary soils are moderately deep or deeper.

They are medium textured with high rock contents throughout. The vegetation is

a mosaic of coniferous forest and forested scree, with substantial rock

outcrops. Mean annual precipitation ranges from 25 to 75 centimeters (10 to 30

inches). The elevation range of this LTA is 1159 to 2288 meters (3800 to 7500

feet). The dominant slopes have gradients of 60 to 90 percent. This LTA is

highly to slightly dissected (closely to widely spaced drainages) and weakly

or moderately incised by streams, with the dominant stream patterns being

subparallel.

LTA Components: This landtype association consists of structural breaks.

Structural breaks are formed in colluvium and residiuum. Slope gradients range

from 60 to 90 percent. Soils on these landforms are mostly moderately deep or

deeper to bedrock, weakly developed and are loams dominated by gravel size

rock fragments throughout These soils are classified as Typic Ustochrepts and

Typic Cryochrepts. Rock outcrop and associated talus occurs on about 40 to 50

percent or more over much of this landscape component. The amount of rock

outcrop and scree is around 20 percent or less. The dominant potential natural

vegetation is Douglas-fir series on higher energy aspects and subalpine fir

and spruce series on more northerly aspects. Forested and non-forested scree

occur throughout. This component represents 100 percent of this LTA.

Compiled by: Larry Laing, Helena National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 447
LTA34-331D

LTA34-M332D

LTA34-M332C

HIGH RELIEF MOUNTAIN SLOPES: VOLCANICS

Location: This LTA is located in the Highwood, Little Belt, and Crazy

Mountains. It also occurs in the foothills of the Belt and Little Belt

Mountains.

 Acreage by Section

 34-331D 6,622

 34-M332D 15,602

 34-M332C 233

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs on very steep mountain slopes

composed of convex ridges and shoulders in complex with smooth surfaces.

Parent materials include sandstone, granite, and basalt.

Accessory Characteristics: The primary soil is shallow to moderately deep

very gravelly or stony loam or sandy loam. The vegetation is coniferous

forest. Mean annual precipitation ranges from 46 to 76 centimeters (18 to 30

inches). The elevation range is 1830 to 2288 meters (6,000 to 7,500 feet). The

dominant slopes have gradients of greater than 60 percent. This LTA is

slightly dissected by streams with the dominant stream pattern being

dendritic. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of very steep mountain

slopes.

These mountain slopes are formed in sandstone, granite and basalt. Slope

gradient is greater than 60 percent. Soils on this landform are shallow to

moderately deep, weakly developed and consists mainly of very gravelly or

stony colluvial material. These soils are classified as Typic Cryochrepts.

Typically 10 to 25 percent of this association consists of rock outcrop. The

dominant potential vegetation is subalpine fir series with some scree. This

component represents the entirety of this LTA.

Compiled by: Rich Saunders, Lewis and Clark National Forest

Revised by Larry Laing, Helena, and Lewis and Clark National Forests

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 448
LTA36-331D

LTA36-M332D

LTA36-M332C

HIGH RELIEF MOUNTAIN SLOPES: SANDSTONES AND SHALES

Location: This LTA is located throughout the Lewis and Clark National Forest

except in the Little Snowy Mountains.

 Acreage by Section

 36-331D 764

 36-M332D 12,477

 36-M332C 13,447

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs on very steep, unglaciated

mountain slopes typically composed of convex ridges and shoulders in complex

with smooth surfaces. Parent materials are non-carbonate and sedimentary.

Accessory Characteristics: The primary soils are shallow to moderately deep

extremely gravelly loams. The vegetation is coniferous forest. Mean annual

precipitation ranges from 51 to 102 centimeters (20 to 40 inches). The

elevation range of this LTA is 1829 to 2743 meters (6000 to 9000 feet). The

dominant slopes have gradients of greater than 60 percent. This LTA is

slightly dissected by streams with the dominant stream pattern being radial.

Wetlands and lakes are virtually non-existent in this LTA.

LTA Components: This landtype association consists of convex ridges, and

shoulders in complex with smooth surfaces. All of these landforms occur on

non-carbonate sedimentary parent material.

The convex ridges and shoulders have slope gradient of 25 to greater than 60

percent. Soils on these landforms are shallow to moderately deep, poorly

developed, and consist mainly of extremely gravelly sandy loam. The major

soils are classified as Typic Cryochrept. Rock outcrop and talus occur on 75

percent of this unit. The dominant potential natural vegetation series is

subalpine fir-whitebark pine.

Compiled by: Richard Saunders, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 449
LTA43-331D

LTA43-M332D

LTA43-M332C

LTA43-M333C

STEEP GLACIATED MOUNTAIN SLOPES: CARBONATES

Location: This LTA is located mostly on the Rocky Mountain Front portion of

the Lewis and Clark National Forest.

 Acreage by Section

 43-331D 624

 43-M332D 12,878

 43-M332C 158,089

 43-M333C 235

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occupies high elevation landscapes

where alpine glaciation has occurred. It is typically occupied by fault

escarpments (mostly in M332C), cirques, troughwalls, and ridges. The parent

material is limestone.

Accessory Characteristics: The primary soils are Lithic Cryorthents and

Cryochrepts. The vegetation is coniferous forest. Mean annual precipitation

ranges from 76 to 127 centimeters (30 to 50 inches). The elevation range of

this LTA is 1524 to 2438 meters (5000 to 8000 feet). The dominant slope

gradients are 70 to 90 percent. This LTA is moderately dissected by streams

and the dominant drainage pattern is dendritic. Wetlands, lakes, and ponds are

a minor component of this LTA.

LTA Components: This landtype association consists of steep west facing

slopes, very steep glacial breaks, and rockland/scree on fault escarpments.

The steep west facing slopes are formed in limestone. These slopes have

gradient ranging from 40 to 60 percent. Soils on these landscapes are shallow,

poorly developed, and consist mainly of loam and flaggy gravel. These soils

are classified as Lithic Cryorthents. Rock outcrop occurs on less than 15

percent of this landscape component. The dominant potential vegetation series

are open growing wind deformed Douglas-fir, limber pine, and spruce on a scree

habitat type. This component represents 30 percent of this LTA.

The very steep glacial breaks are formed in limestone. Slope gradients are

mainly greater than 60 percent. The soil on this landscape is deep, poorly

developed, and consist mainly of sandy loam and gravel. These soils are

classified as Typic Cryochrepts. Rock outcrop and talus occur on seventy five

percent of this landscape component. The dominant potential natural vegetation

series is Douglas-fir. This component represents 30 percent of this LTA.

The rockland/scree component occurs on fault escarpments in limestone. Slopes

are mainly greater than 60 percent. Soil on this landscape consists of sandy

loam, loamy sand, gravel, and cobble. These materials are classified as scree.

The dominant potential vegetation is subalpine fir-whitebark pine. This

component represents 40 percent of this LTA.

Compiled by: Richard Saunders and Robin Strathy, Lewis and Clark National

Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 450
LTA44-331D

LTA44-M332D

LTA44-M332C

STEEP GLACIATED MOUNTAIN SLOPES: SANDSTONES AND SHALES

Location: This LTA is extensive throughout the Rocky Mountain Division on the

Lewis and Clark Forest and in the Elkhorn Mountains on the Beaverhead

-Deerlodge Forest.

 Acreage by Section

 44-331D 98

 44-M332D 15,947

 44-M332C 101,583

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occupies high elevation landscapes

where alpine glaciation has occurred. It is typically composed of glacial

cirque headwalls and rockland/scree on fault escarpments in Section M332C, and

glacial cirques in Section M332D. The parent material is sandstone and/or

shale.

Accessory Characteristics: The primary soils are deep extremely cobbly sandy

loams and loams. The vegetation is coniferous forest. Mean annual

precipitation ranges from 63 to 88 centimeters (25 to 35 inches). The

elevation range of this LTA is 1500 to 2896 meters (5000 to 9000 feet). The

dominant slopes have gradients of 40 to greater than 60 percent. This landtype

is moderately dissected by streams, with the dominant stream pattern being

parallel. Wetlands are a minor component of this LTA.

LTA Components: This map unit consists of glacial cirques, rockland, and scree

on fault escarpments

Glacial cirques are formed in sandstone and shale. Soils on these landforms

are from very shallow to moderately deep, poorly developed, and consist mainly

of sandy loam and angular cobble. The major soils are classified as Typic,

Andic and Lithic Cryochrepts. Rock outcrop occurs on 5 to 15 percent of this

landscape component. The dominant potential natural vegetation is subalpine

fir and whitebark pine series. This component represents 60 percent of this

unit.

Rockland occurs on a variety of non-carbonate rocks. This component is a

miscellaneous landtype and is classified as scree. It does support some alpine

fir and whitebark pine. This component represents 25 percent of this LTA.

Compiled by: Richard Saunders and Robin Strathy, Lewis and Clark National

Forest, and Dave Ruppert, Beaverhead-Deerlodge National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 451
LTA53-331D

GLACIATED MOUNTAIN SLOPES: SANDSTONES AND SHALES

Location: This LTA is located in the Rocky Mountain Front foothills on the

Lewis and Clark National Forest.

 Acreage by Section

 53-331D 3,058

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs on an alpine glacial till

landform which is typically composed of outwash benches, drift plastered

trough walls, and hilly valley bottoms. Parent materials are sandstones and

shales.

Accessory Characteristics: The primary soils are deep, very cobbly loams. The

vegetation is subalpine forest. Mean annual precipitation ranges from 63 to 88

centimeters (25 to 35 inches). The elevation range of this LTA is 1524 to 1981

meters (5000 to 6500 feet). The dominant slopes have gradients of 10 to 40

percent. This landtype association is moderately dissected by streams with the

dominant stream pattern being parallel. Wetlands are a minor component of this

LTA.

LTA Components: This landtype association consists of clayey glacial drift

deposits, drift plastered trough walls, and hilly glaciated valleys.

The clayey glacial drift deposits are formed mainly in sandstone and shale

material. Slope gradients range from 10 to 40 percent. The soils on these

landforms are deep, weakly developed, skeletal loams. These soils are

classified as Andic Cryochrepts. Rock outcrop occurs on about 10 percent of

this landscape. The dominant potential natural vegetation series is subalpine

fir.

The drift plastered trough walls are formed mainly in sandstone and shale

material. Slope gradients range from 25 to 40 percent. The soils on these

landforms are deep, weakly developed, and loamy-skeletal. These soils are

classified as Typic Cryochrepts. Rock outcrop occurs on about 10 percent of

this landscape. The dominant potential natural vegetation series is

Douglas-fir.

The hilly glaciated valleys are formed mainly in sandstone and shale. Slope

gradients range from 10 to 25 percent. The soils on these landforms are

moderately deep, weakly developed, clay loams with 35 to 50 percent gravel.

These soils are classified as Argic Cryoborolls. Rock outcrop occurs on less

than 5 percent of this LTA. The dominant natural vegetation series is rough

fescue.

Compiled by: Richard Saunders and Robin Strathy, Lewis and Clark National

Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 452
LTA64-331D

LTA64-M332Db

MOUNTAIN SLOPES AND RIDGES: VOLCANICS

Location: This LTA is located mostly in the Highwood and Castle mountain

ranges in central Montana in the Missouri River Basin. Smaller amounts occur

in the Little Belt, Snowy and Judith Mountains.

 Acreage by Subsection

 64-331D 26,813

 64-M332Db 3,239

LTA Setting and General Characteristics: 

Differentiating Characteristics: This LTA occurs in a mountain slope landscape

setting, which is typically composed of moderately steep to steep mountain

slopes and valley sideslopes. Parent materials are latite, rhyolites, and

shonkinites. 

Accessory Characteristics: The primary soils are well drained, 20 to 60 inches

deep, slightly acidic to neutral and loamy skeletal. Vegetation is a complex

of grassland and lodgepole pine forest. Mean annual precipitation ranges from

51 to 76 centimeters (20 to 30 inches). The elevation range of this LTA is

1371 to 1982 meters (4500 to 6500 feet). The dominant slopes have gradients of

25 to 60 percent. This LTA is well dissected by streams, with the dominant

stream pattern being subparallel. Wetlands are a minor component of this LTA.

LTA Components: This landtype association consists of stream dissected

mountain slopes.

Stream dissected mountain slopes are formed in colluvium derived from

rhyolite, latite, and shonkinite parent materials. Slope gradients range from

25 to 60 percent. Soils on these landforms are weakly developed, 20 to 60

inches in depth; loam topsoils are 4 to 10 inches thick, subsoils are brown

loam with 10 to 75 percent cobble. These soils are classified as Typic

Cryochrepts. Rock outcrop occurs on about 10 percent of this landscape

component. The dominant potential natural vegetation is Douglas-fir at lower

elevations, and subalpine fir at higher elevations. 

Compiled by: Robin Strathy, Lewis and Clark National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 453
LTA68-331D

LTA68-M332D

LTA68-M332C

MOUNTAIN SLOPES AND RIDGES: SANDSTONES AND SHALES

Location: This LTA is located in the Little Belt Mountains and along the Rocky

Mountain Front on the Lewis and Clark National Forest, and in the Elkhorn

Mountains on the Beaverhead-Deerlodge Forest.

 Acreage by Section

 68-331D 8,549

 68-M332D 336,244

 68-M332C 80,557

Map Unit Setting and General Characteristics

Differentiating Characteristics: This LTA occurs in a mountain slope or ridge

setting which is typically composed of stream dissected mountain slopes and

ridges. Parent materials are sandstone and shale.

Accessory Characteristics: The primary soils are moderately deep, skeletal

loamy sands and loams. The vegetation is a mosaic of subalpine fir and rough

fescue series. Mean annual precipitation ranges from 36 to 89 centimeters (14

to 35 inches). The elevation range of this LTA is 1524 to 2438 meters (5000 to

8000 feet). This LTA is moderately dissected by streams with the dominant

pattern being parallel. Wetlands are a minor component.

LTA Components: This landtype association consists of low relief ridges and

slopes, and steep valley sideslopes.

The low relief ridges and slopes are formed in sandstone and shale. Slope

gradients are from 10 to 40 percent. Soils on these landforms are moderately

deep to deep, moderately well developed, extremely gravelly loams. These soils

are classified as Typic and Argic Cryoborolls. Rock outcrop occurs on about 5

percent of this landscape component. The dominant potential natural vegetation

is rough fescue and subalpine fir. This component represents 55 percent of

this LTA.

The steep valley sideslopes are formed in sandstone and shale. Slope gradients

are from 40 to 60 percent. The soils are classified as Typic and Andic

Cryochrepts in Subsections 331Da, 331Db, and 331Dc, M332Cb, M332Cd, M332Dc,

and M332Dd; soils in subsection M332Dm are Cryoboralfs. Rock outcrop occurs on

about 10 percent of this landscape component. The dominant potential natural

vegetation is subalpine fir. This component represents 30 percent of this LTA.

Compiled by: Richard Saunders and Robin Strathy, Lewis and Clark National

Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 454
LTA90-331D

LTA90-M332D

LTA90-M332C

MASS WASTED SLOPES: MIXED GEOLOGY

Location: This LTA is located primarily in the Little Belt and Big Snowy

Mountain Ranges on the Lewis and Clark Forest.

 Acreage by Section

 90-331D 2,576

 90-M332D 73,847

 90-M332C 67,272

LTA Setting and General Characteristics:

Differentiating Characteristics: This LTA occurs in a mountainous landscape

setting, which is typically composed of valley sideslopes and benchy lower

valley slopes. The primary parent material is shale, but some undifferentiated

material is also present. 

Accessory Characteristics: The primary soils are deep, clayey and skeletal

silt loams and silty clay loams. The vegetation is coniferous forest. Mean

annual precipitation is 51 to 76 centimeters (20 to 30 inches). The elevation

range of this LTA is 1350 to 2100 meters (4500 to 7000 feet). The dominant

slopes have gradients of 10 to 40 percent. This LTA is moderately dissected,

with the dominant stream pattern being dendritic.

LTA Components: This landtype association consists of rotational slumps and

mud flows, benchy lower valley slopes, and upper valley sideslopes.

Rotational slumps and mud flows are formed shale. Slope gradients range from

10 to 40 percent. Soils on these landforms are moderately deep, weakly 

developed, and consist of mainly of loam, silt loam, and cobble. The major

soils are classified as Typic Cryochrepts. Rock outcrop occurs on less than 15

percent of this LTA. The dominant potential natural vegetation is subalpine

fir. This component represents 55 percent of this LTA.

Benchy lower valley slopes are formed in shale. Slope gradients range from 10

to 40 percent. Soils on these landforms are moderately deep and deep, weakly

developed, and consist of loam, silt loam and gravel. The major soils are

classified as Typic Cryoboralfs. Rock outcrop occurs on less than 15 percent

of this LTA. The dominant potential natural vegetation is Douglas-fir. This

component represents 30 percent of this LTA.

Upper valley sideslopes are formed in shale. Slope gradients range from 10 to

25 percent. Soils on these landforms shallow, moderately developed and consist

mainly of loam and cobble. The major soils are classified as Mollic

Cryoboralfs. Rock outcrop occurs on less than 15 percent of this LTA. The

dominant potential natural vegetation is Douglas-fir. This component

represents 15 percent of this LTA.

Compiled by: Richard Saunders and Robin Strathy Lewis and Clark National

Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 455
SECTION 331F NORTHWESTERN GREAT PLAINS

Only that portion of this Section which occurs in southeastern North Dakota is

within the Northern Region of the Forest Service. This section includes gently

sloping to rolling, moderately dissected shale plains. Bedrock consists of

soft Cretaceous and Lower Tertiary non-marine sedimentary formations.

SECTION 331G POWDER RIVER BASIN

This Section occurs in southeast Montana and northeast Wyoming. This area

includes gently rolling to steep dissected plains on the Missouri Plateau.

Wide belts of steeply sloping badlands border a few of the larger river

valleys. In places, flat-topped, steep sided buttes rise sharply above the

surrounding plains. There are Cretaceous and Lower Tertiary non--marine

sedimentary rocks. Glacial lake beds also occur.

LTA1-331F

LTA1-331G

PLAINS: SHALES, SILTSTONES, AND SANDSTONES

Location: This unit is located in western North Dakota and northwest South

Dakota on the Custer National Forest.

 Acreage by Section

 1-331F 946,770

 1-331G 21,416

LTA Setting and General Characteristics

Differentiating Characteristics: This unit occurs in a rolling plains

landscape setting, which is typically composed of hills and swales. Parent

materials are residuum underlain by shale, siltstone and sandstone.

Accessory Characteristics: The primary soils are shallow to deep, with

moderately coarse to fine textures. The vegetation is a mosaic of prairie

grasslands and shrubland. Mean annual precipitation ranges from 36 to 41 cms

(14 to 16 inches). The elevation range is 540 to 1000 meters (1770 to 3280

feet). The dominant slopes have gradients of 2 to 15 percent. This unit is

moderately dissected by streams, with the dominant stream pattern being

dendritic. 

LTA Components: This landtype association consists of hills and swales.

Hills are formed in residuum. Slope gradients range from 2 to 15 percent.

Soils on these landforms are shallow to deep, moderately developed, with

moderately coarse to moderately fine textures. These soils are classified as

Typic Ustorthents, Leptic Natriborolls, and Typic Argiborolls. The dominant

potential natural vegetation is Western wheatgrass, needle and thread, little

bluestem and prairie sandreed. This component represents 60 percent of this

unit.

Swales are formed in residuum and alluvium. Slope gradients range from 2 to 15

percent. Soils on these landforms are shallow to deep, moderately developed,

with moderately coarse to moderately fine textures. These soils are classified

as Typic Ustorthents, Borollic Natrargids, and Typic Argiborolls. The dominant

potential natural vegetation is western wheatgrass. Other communities include

big bluestem and silver sagebrush, green ash, and western snowberry. This

component represents 40 percent of this unit.

Compiled by: John R. Lane, Custer National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 456
LTA2-331F

GLACIATED PLAINS: SHALES, SILTSTONES, AND SANDSTONES

Location: This unit is located in west central North Dakota on the Custer

National Forest.

 Acreage by Section

 2-331F 32,403

LTA Setting and General Characteristics

Differentiating Characteristics: This unit occurs in a gently undulating to

rolling continental glacial till plain, which is typically composed of hills,

and drainageways. Parent materials are glacial till underlain by shale,

siltstone and sandstone.

Accessory Characteristics: The primary soils are shallow to deep, with medium

textures. The vegetation is a mosaic of prairie grasslands and some

shrublands. Mean annual precipitation ranges from 36 to 41 cms. (14 to 16

inches). The elevation range is 560 to 750 meters (1835 to 2460 feet). The

dominant slopes have gradients of 0 to 15 percent. This unit is slightly to

moderately dissected by streams, with the dominant stream pattern being

dendritic. Riparian areas and wetlands are a minor component of this unit.

LTA Components: This landtype association consists of hills and drainageways.

Hills are formed in glacial till. Slope gradients range from 2 to 25 percent.

Soils on these landforms are shallow to deep, moderately developed, with

medium and medium textures. These soils are classified as Entic Haploborolls,

Typic Argiborolls, and Typic Ustorthents. Rock outcrop occurs on about 10

percent of this landscape component. The dominant potential natural vegetation

includes Western wheatgrass, needle and thread, little bluestem, prairie

sandreed. Skunkbrush, horizontal juniper may be found on steeper drier slopes.

 This component represents 60 percent of this unit.

Drainageways and swales are formed in glacial till. Slope gradients range from

0 to 9 percent. Soils on these landforms are shallow to deep, moderately

developed, with medium and medium textures. These soils are classified as

Entic Haploborolls, Typic Argiborolls, and Typic Ustorthents. The dominant

potential natural vegetation is western wheatgrass series. Other communities

include big bluestem and silver sagebrush, green ash, western snowberry and

buffalo berry. This component represents 40 percent of this unit.

Compiled by: John R. Lane, Custer National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 457
LTA3-331F

LTA3-331G

DISSECTED PLAINS: SHALE, SILTSTONE, AND SANDSTONE

Location: This unit is located in western North Dakota, northwest South

Dakota, and southeast Montana on the Custer National Forest.

 Acreage by Section

 3-331F 515,063

 3-331G 53,589

LTA Setting and General Characteristics

Differentiating Characteristics: This unit occurs in gently sloping to rolling

shale plains landscape setting, which is typically composed of hills,

drainages and ridges. Parent materials are residuum underlain by sandstone,

siltstone and shale.

Accessory Characteristics: The primary soils are shallow to deep, with coarse

to medium textures. The vegetation is a mosaic of shrublands, and prairie

grasslands. Mean annual precipitation ranges from 31 to 51 cms (12 to 20

inches). The elevation range is 540 to 950 meters (1770 to 3120 feet). The

dominant slopes have gradients of 6 to 50 percent. This unit is moderately to

strongly dissected by streams, with the dominant stream pattern being

dendritic with subparallel in some areas.

LTA Components: This landtype association consists of hills, drainages, and

knobs.

Hills are formed in residuum. Slope gradients range from 6 to 50 percent.

Soils on these landforms are shallow to moderately deep, moderately developed,

with moderately coarse to medium textures. These soils are classified as Typic

Ustorthents, Typic Argiborolls, Typic Haploborolls, Typic Ustipsamments, and

badlands. Rock outcrop occurs on about 10 percent of this landscape

component. The dominant potential natural vegetation includes Western

wheatgrass, needle and thread, little bluestem, prairie sandreed. Skunkbrush,

horizontal juniper, green ash, rocky mountain juniper, and shrubby cinquefoil

may be found on steeper slopes. This component represents 40 percent of this

unit.

Drainages are formed in residuum and alluvium. Slope gradients range from 2 to

25 percent. Soils on these landforms are moderately deep, moderately

developed, with medium and moderately coarse textures. These soils are

classified as Typic Ustorthents, Typic Argiborolls, and Typic Haploborolls.

The dominant potential natural vegetation is Western wheatgrass. Other

communities include big bluestem, silver sagebrush, green ash, western

snowberry buffalo berry, silver sagebrush. This component represents 35

percent of this unit.

Knobs are formed in residuum. Slope gradients range from 8 to 35 percent.

Soils on these landforms are shallow to deep, moderately developed, with

coarse to medium textures. These soils are classified as Typic Ustorthents,

Borollic Natrargids, Typic Ustipsamments, Typic Haploborolls. Rock outcrop

occurs on about 10 percent of this landscape component. The dominant potential

natural vegetation on drier slopes includes big sagebrush, shadscale,

greasewood and skunkbrush. On mesic slopes, buffalo berry, horizontal juniper,

western wheatgrass, needle and thread, green ash and rocky mountain juniper

communities are found. This component represents 25 percent of this unit.

Compiled by: John R. Lane, Custer National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 458
LTA4-331F

GLACIATED DISSECTED PLAINS: SHALES, SILTSTONES, AND SANDSTONES

Location: This unit is located in west central North Dakota on the Custer

National Forest.

 Acreage by Section

 4-331F 27,111

LTA Setting and General Characteristics

Differentiating Characteristics: This unit occurs in a high relief continental

glacial till plains landscape setting, which is typically composed of

hillsides, and drainageways. Parent materials are glacial till and residuum

underlain by sandstone, siltstone and shale.

Accessory Characteristics: The primary soils are shallow to deep, with medium

textures. The vegetation is a mosaic of prairie grasslands. Mean annual

precipitation ranges from 36 to 41 cms (14 to 16 inches). The elevation range

is 570 to 740 meters (1870 to 2425 feet). The dominant slopes have gradients

of 6 to 25 percent. This unit is moderately dissected by streams, with the

dominant stream pattern being dendritic. Wetlands and riparian areas are a

minor component of this unit.

LTA Components: This landtype association consists of hillsides and

drainages.

Hillsides are formed in glacial till. Slope gradients range from 6 to 25

percent. Soils on these landforms are shallow to moderately deep, moderately

developed, with medium and medium textures. These soils are classified as

Typic Argiborolls, Entic Haploborolls and Typic Ustorthents. Rock outcrop

occurs on about 10 percent of this landscape component. The dominant potential

natural vegetation includes western wheatgrass, needle and thread, little

bluestem, prairie sandreed. Skunkbrush, horizontal juniper, green ash, rocky

mountain juniper, and shrubby cinquefoil may be found on steeper slopes. This

component represents 60 percent of this unit.

Drainageways are formed in glacial till and residuum. Slope gradients range

from 6 to 40 percent. Soils on these landforms are shallow to deep, moderately

developed, with medium textures. These soils are classified as Entic

Haploborolls, and Typic Ustorthents. The dominant potential natural vegetation

is western wheatgrass. Other communities include big bluestem and silver

sagebrush, green ash, western snowberry and buffalo berry, and silver

sagebrush. This component represents 40 percent of this unit.

Compiled by: John R. Lane, Custer National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 459
LTA5-331F

LTA5-331G

BADLANDS: SHALES, SILTSTONES, AND SANDSTONES

Location: This unit is located in western North Dakota and northwest South

Dakota on the Custer National Forest.

 Acreage by Section

 5-331F 783,355

 5-331G 429

LTA Setting and General Characteristics

Differentiating Characteristics: This unit occurs in a rugged, deeply eroded

dissected shale plains landscape setting, which is typically composed of

knobs, hillsides, and entrenched channels. Parent materials are residuum and

alluvium underlain by shale, siltstone and sandstone.

Accessory Characteristics: The primary soils are shallow to moderately deep

with moderately coarse to moderately fine textures. The vegetation is a mosaic

of prairie grasslands, shrubland, and coniferous forest. Mean annual

precipitation ranges from 36 to 41 cms (14 to 16 inches). The elevation range

is 580 to 960 meters (1900 to 3150 feet). The dominant slopes have gradients

of 6 to greater than 40 percent. This unit is moderately dissected by streams,

with the dominant stream pattern being dendritic.

LTA Components: This landtype association consists of knobs, hillsides and

entrenched channels.

Knobs are formed in residuum. Slope gradients range from 6 to 50 percent.

Soils on these landforms are shallow to deep, moderately developed, with

coarse to medium textures. These soils are classified as Typic Haploborolls,

Typic Ustorthents, and Leptic Natriborolls. Rock outcrop occurs on about 40

percent of this landscape component. The dominant potential natural vegetation

on drier slopes includes big sagebrush, shadscale, greasewood and skunkbrush.

On mesic slopes, buffalo berry, horizontal juniper, western wheatgrass,

needle and 

thread, green ash and rocky mountain juniper communities are found. This

component represents 35 percent of this unit.

Hillsides are formed in residuum. Slope gradients range from 6 to 50 percent.

Soils on these landforms are shallow to moderately deep, moderately developed,

with coarse to medium textures. These soils are classified as Typic

Ustorthents, Typic Haploborolls, and Typic Ustipsamments. Rock outcrop occurs

on about 20 percent of this landscape component. The dominant potential

natural vegetation on drier slopes includes big sagebrush, shadscale,

greasewood and skunkbrush. On mesic slopes, buffalo berry, horizontal juniper,

western wheatgrass, needle and thread, green ash and rocky mountain juniper,

western wheatgrass, little bluestem and prairie sandreed communities are

found. This component represents 35 percent of this unit.

Entrenched channels are formed in residuum and alluvium. Slope gradients range

from 6 to 30 percent. Soils on these landforms are shallow to deep, moderately

developed, with medium to coarse textures. These soils are classified as Typic

Haploborolls, Typic Ustorthents, and Leptic Natriborolls. Rock outcrop occurs

on about 20 percent of this landscape component. The dominant potential

natural vegetation includes silver sagebrush, western snowberry, green ash,

western wheatgrass, buffalo berry, and inland saltgrass. This component

represents 30 percent of this unit.

Compiled by: John R. Lane, Custer National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 460
LTA6-331F

LTA6-331G

ERODED UPLANDS: VOLCANIC TUFFS, SHALES, SILTSTONES, AND SANDSTONES

Location: This unit is located in southeast Montana and western South Dakota

on the Custer National Forest.

 Acreage by Section

 6-331F 116,337

 6-331G 190,412

LTA Setting and General Characteristics

Differentiating Characteristics: This unit occurs in a undulating to steep

dissected shale plains landscape setting, which is typically composed of

ridges, plateaus, hillsides and rimrocks. Parent materials are residuum, and

colluvium underlain by volcanic tuffs, shales, siltstones and sandstones.

Accessory Characteristics: The primary soils are shallow to deep, with

moderately coarse to moderately fine textures. The vegetation is a mosaic of

coniferous forest, prairie grassland, and deciduous forest. Mean annual

precipitation ranges from 31 to 51 cms (12 to 20 inches). The elevation range

is 900 to 1400 meters (2950 to 4600 feet). The dominant slopes have gradients

of 15 to 60 percent. This unit is moderately to strongly dissected by streams,

with the dominant stream pattern being dendritic and parallel in the southern

Ekalaka Hills.

LTA Components: This landtype association consists of ridges, plateaus,

hillsides, and rimrocks.

Ridges are formed in colluvium and residuum. Slope gradients range from 8 to

70 percent. Soils on these landforms are shallow to deep, poorly developed,

with very gravelly moderately coarse to moderately fine textures. These soils

are classified as Typic Ustochrepts, Typic Ustorthents, and Mollic

Eutroboralfs. Rock outcrop occurs on about 25 percent of this landscape

component. The dominant potential natural vegetation on ridge tops are needle

and thread, Idaho fescue, and western wheatgrass. Ponderosa pine, green ash

and rocky mountain juniper are found on steep sideslopes. This component

represents 30 percent of this unit.

Plateaus are formed in colluvium and residuum. Slope gradients range from 4 to

15 percent. Soils on these landforms are shallow to deep, poorly to moderately

developed, with moderately coarse to moderately fine textures. These soils are

classified as Mollic Eutroboralfs, Typic Haploborolls, and Typic Ustorthents.

Rock outcrop occurs on about 5 percent of this landscape component. The

dominant potential natural vegetation is needle and thread, Idaho fescue,

western wheatgrass and big sagebrush. Little bluestem and prairie sandreed are

inclusions which occur on shallow sites or sites with coarse textured soils.

This component represents 25 percent of this unit.

Hillsides are formed in colluvium and residuum. Slope gradients range from 6

to 60 percent. Soils on these landforms are shallow to moderately deep,

moderately developed, with coarse to very gravelly moderately fine textures.

These soils are classified as Lithic Ustorthents, Mollic Eutroboralfs, and

Typic Eutroboralfs. Rock outcrop occurs on about 10 percent of this landscape

component. The dominant potential natural vegetation is ponderosa pine, green

ash and rocky mountain juniper on steep sideslopes. Other series found include

skunkbrush, horizontal juniper, bluebunch wheatgrass and little bluestem. 

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 461
This component represents 25 percent of this unit.

Rimrocks are formed in colluvium and residuum. Slope gradients range from 15

to 60 percent. Soils on these landforms are shallow to moderately deep, weakly

to moderately developed, with coarse to moderately fine textures. These soils

are classified as Ustic Torriorthents, Typic Eutroboralfs, and Typic

Ustorthents. Rock outcrop occurs on about 40 percent of this landscape

component. This component is relatively non-vegetated, but includes patches

of ponderosa pine, rocky mountain juniper and skunkbrush. This component

represents about 20 percent of this unit.

Compiled by: John R. Lane, Custer National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 462
LTA7-331F

LTA7-331G

EROSIONAL PLATEAUS AND BUTTES: SHALES, SILTSTONES, AND SANDSTONES

Location: This unit is located in western North Dakota, northwest South Dakota

and southeast Montana on the Custer National Forest.

 Acreage by Section

 7-331F 22,819

 7-331G 161,941

LTA Setting and General Characteristics

Differentiating Characteristics: This unit occurs in a rolling to steep

dissected shale plains landscape setting, which is typically composed of

buttes, plateaus, ridges and channels. Parent materials are residuum underlain

by shale, siltstone and sandstone.

Accessory Characteristics: The primary soils are shallow to deep, with coarse

to moderately fine textures. The vegetation is a mosaic of prairie

grasslands. Mean annual precipitation ranges from 30 to 51 cms. (12 to 20

inches). The elevation range is 820 to 1020 meters (2690 to 3345 feet). The

dominant slopes have gradients of 2 to greater than 60 percent. This unit is

moderately to strongly dissected by streams, with the dominnt stream pattern

being dendritic.

LTA Components: This landtype association consists of buttes, ridges and

plateaus.

Buttes are formed in residual sandstone and shale. Slope gradients range from

2 to greater than 60 percent. Soils on these landforms are shallow to

moderately deep, moderately developed, with coarse to moderately fine

textures. These soils are classified as Typic Haploborolls, Typic

Ustipsamments, and Typic Ustothents. Rock outcrop occurs on about 20 percent

of this landscape component. The dominant potential natural vegetation

includes needle and thread, western wheatgrass, blue bunch wheatgrass,

skunkbrush, little bluestem, green ash, rocky mountain juniper, ponderosa pine

and buffalo berry. This component represents 35 percent of this unit.

Ridges are formed in residual sandstone and shale. Slope gradients range from

6 to 40 percent. Soils on these landforms ares shallow to moderately deep,

moderately developed, with coarse to moderately fine textures. These soils are

classified as Leptic Natriborolls, Typic Haploborolls, Typic Ustipsamments.

Rock outcrop occurs on about 35 percent of this landscape component. The

dominant potential natural vegetation on ridge tops are needle and thread,

Idaho fescue and western wheatgrass. Ponderosa pine, green ash and rocky

mountain juniper are found on steep sideslopes. This component represents 30

percent of this unit.

Plateaus are formed in loamy residuum, and colluvium. Slope gradients range

from 0 to 10 percent. Soils in these landforms are shallow to deep, moderately

developed, with medium and moderately fine textures. These soils are

classified as Typic Argiborolls, Lithic Ustorthents, Typic Natriborolls, and

Entic Haploborolls. Rock outcrop occurs on about 15 percent of this landscape

component. The dominant potential natural vegetation includes needle and

thread, Idaho fescue, western wheatgrass and big sagebrush. Ponderosa pine

occurs on steeper slopes and heads of drainages. Little bluestem and prairie

sandreed are inclusions which occur on shallow sites or sites with coarse

textured soils. This component represents 35 percent of this unit.

Compiled by: John R. Lane, Custer National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 463
LTA10-331F

VALLEYS: RECENT COARSE ALLUVIUM

Location: This unit is located in western North Dakota on the Custer National

Forest.

 Acreage by Section

 10-331F 5,917

LTA Setting and General Characteristics

Differentiating Characteristics: This unit occurs in a undulating to rolling

continental glacial till plains landscape setting, which is typically composed

of stream channels, flood plains and terraces. Parent materials are fine to

coarse alluvium and glacial till underlain by shale, siltstone, and sandstone.

Accessory Characteristics: The primary soils are deep, with medium textures.

The vegetation is a mosaic of prairie grasslands and shrublands. Mean annual

precipitation ranges from 31 to 41 cms. (14 to 16 inches). The elevation range

is 550 to 600 meters (1805 to 1970 feet). The dominant slopes have gradients

of 0 to 8 percent. This unit is slightly dissected by streams, with the

dominant stream pattern being dendritic. Wetlands are a minor component of

this unit.

LTA Components: This landtype association consists of stream channels, flood

plains and terraces.

Stream channels are formed in alluvium. Slope gradients range from 0 to 6

percent. Soils on these landforms are deep, weakly to moderately developed,

with coarse to medium textures. These soils are classified as Ustic

Torrifluvents, and Typic Ustifluvents. The dominant potential natural

vegetation includes green ash, plains cottonwood, western snowberry, baltic

rush, inland saltgrass, Alkali grass and prairie cordgrass. This component

represents 35 percent of this unit.

Flood plains are formed in alluvium. Slope gradients range from 0 to 10

percent. Soils on these landforms are deep, weakly developed, with coarse to

medium textures. These soils are classified as Ustic Torrifluvents, and Typic

Ustifluvents. The dominant potential natural vegetation includes western

wheatgrass, silver sagebrush, western snowberry, green ash, plains cottonwood,

inland saltgrass, and Alkali grass. This component represents 35 percent of

this unit.

Terraces are formed in alluvium. Slope gradients range from 0 to 10 percent.

Soils on these landforms are deep, moderately developed, with coarse to medium

textures. These soils are classified as Ustic Torrifluvents, Typic

Argiborolls, and Typic Ustifluvents. The dominant potential natural vegetation

includes western wheatgrass, silver sagebrush, western snowberry, inland

saltgrass, and greasewood. This component represents 30 percent of this unit.

Compiled by: John R. Lane, Custer National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 464
LTA12-331F

VALLEYS: OUTWASH OR OLDER COARSE ALLUVIAL DEPOSITS

Location: This unit is located in western North Dakota and northwestern South

Dakota on the Custer National Forest.

 Acreage by Section

 12-331F 50,843

LTA Setting and General Characteristics

Differentiating Characteristics: This unit occurs in a rolling to steep

dissected shale plains landscape setting, which is typically composed of

terraces. Parent materials are alluvium underlain by older coarser alluvium

and shale and sandstone.

Accessory Characteristics: he primary soils are moderately deep to deep, with

medium and moderately coarse textures. The vegetation is a mosaic of prairie

grasslands. Mean annual precipitation ranges from 36 to 41 cms. (14 to 16

inches). The elevation range is 560 to 1030 meters (1840 to 3380 feet). The

dominant slopes have gradients of 0 to 6 percent. This unit is weakly

dissected by streams, with the dominant stream pattern being dendritic.

LTA Components: This landtype association consists of terraces.

Terraces are formed in alluvium. Slope gradients range from 0 to 6 percent.

Soils on these landforms are moderately deep to deep, moderately developed,

with moderately fine to moderately coarse textures. These soils are classified

as Typic Argiborolls, and Typic Haploborolls. The dominant potential natural

vegetation includes western wheatgrass, silver sagebrush, western snowberry,

inland saltgrass, and greasewood. This component represents 100 percent of

this unit.

Compiled by: John R. Lane, Custer National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 465
LTA14-331F

LTA14-331G

VALLEYS: RECENT FINE ALLUVIUM

Location: This LTA is located in west central North Dakota, western South

Dakota, and eastern Montana on the Custer National Forest.

 Acreage by Section

 14-331F 206,152

 14-331G 27,147

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a gently sloping to

steep dissected plains landscape setting, which is typically composed of

stream channels, flood plains and terraces. Parent materials are fine to

coarse alluvium underlain by shales and sandstones.

Accessory Characteristics: The primary soils are deep, with coarse to fine

textures. The vegetation is a mosaic of deciduous forest, shrublands, and

prairie grasslands. Mean annual precipitation ranges from 31 to 51 cms. (12 to

20 inches). The elevation range is 540 to 900 meters (1770 to 2950 feet). The

dominant slopes have gradients of 0 to 8 percent. This unit is slightly

dissected by streams, with the dominant stream pattern being dendritic.

Wetlands are a minor component of this unit.

LTA Components: This landtype association consists of stream channels, flood

plains and terraces.

Stream channels are formed in alluvium. Slope gradients range from 0 to 4

percent. Soils on these landforms are deep, moderately developed, with coarse

to fine textures. These soils are classified as Typic Ustifluvents, Ustic

Torrifluvents, and Fluvaquents. The dominant potential natural vegetation

includes green ash, plains cottonwood, western snowberry, baltic rush, inland

saltgrass, Alkali grass and prairie cordgrass. This component represents 30

percent of this unit.

Flood plains are formed in alluvium. Slope gradients range from 0 to 10

percent. Soils on these landforms are deep, moderately developed, with coarse

to fine textures. These soils are classified as Typic Ustifluvents, Ustic

Torrifluvents, Typic Argiborolls, and Fluvaquents. The dominant potential

natural vegetation includes western wheatgrass, silver sagebrush, western

snowberry, green ash, plains cottonwood, inland saltgrass and greasewood.

Willow occurs in bands along stream banks. This component represents 35

percent of this unit.

Terraces are formed in alluvium. Slope gradients range from 0 to 8 percent.

Soils on these landforms are deep, strongly developed, with coarse to medium

textures. These soils are classified as Typic Haploborolls, Typic

Ustifluvents, Ustollic Haplargids, and Ustic Torrifluvents. The dominant

potential natural vegetation includes western wheatgrass, silver sagebrush,

western snowberry, inland saltgrass, greasewood, green ash, and plains

cottonwood. This component represents 35 percent of this unit.

Compiled by: John R. Lane, Custer National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 466
LTA25-331F

BREAKS: SANDSTONES AND SHALES

Location: This unit is located in southwestern North Dakota on the Custer

National Forest.

 Acreage by Section

 25-331F 25,390

LTA Setting and General Characteristics

Differentiating Characteristics: This unit occurs in a undulating to rolling

continental glacial till plains landscape setting, which is typically composed

of stream breaklands and structural breaklands. Parent materials are weathered

shale, siltstone, sandstone and glacial till underlain by shale, siltstone and

sandstone.

Accessory Characteristics: The primary soils are shallow to deep, with medium

textures. The vegetation is a mosaic of prairie grasslands. Mean annual

precipitation ranges from 36 to 51 cms. (14 to 20 inches). The elevation range

is 560 to 700 meters (1835 to 2300 feet). The dominant slopes have gradients

of 6 to 30 percent. This unit is strongly dissected by streams, with the

dominant stream pattern being dendritic and parallel.

LTA Components: This landtype association consists of stream breaks and

structural breaks.

Stream breaks are formed in glacial till and residuum. Slope gradients range

from 6 to 40 percent. Soils on these landforms are shallow to deep, moderately

developed, with medium and moderately fine textures. These soils are

classified as Entic Haploborolls, Typic Ustorthents, and rock outcrop. Rock

outcrop occurs on about 35 percent of this landscape component. The dominant

potential natural vegetation includes big sagebrush, shadscale, skunkbrush,

rocky mountain juniper, green ash, needle and thread, westernwheatgrass,

little bluestem and horizontal juniper. This component represents 70 percent

of this unit.

Structural breaks are formed in glacial till. Slope gradients range from 6 to

40 percent. Soils on these landforms are shallow to moderately deep,

moderately developed, with medium and moderately fine textures. These soils

are classified as Typic Argiborolls, Entic Haploborolls, and Typic

Ustorthents. Rock outcrop occurs on about 20 percent of this landscape

component. The dominant potential natural vegetation includes big sagebrush,

shadscale, skunkbrush, rocky mountain juniper, green ash, needle and thread,

western wheatgrass, little bluestem and horizontal juniper. This component

represents 30 percent of this unit.

Compiled by: John R. Lane, Custer National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 467
LTA25-331G

BREAKS, SILTSTONES AND CLAYSTONES

Location: This unit is located in southeast Montana on the Custer National

Forest.

 Acreage by Section

 25-331G 50,254

LTA Setting and General Characteristics

Differentiating Characteristics: This unit occurs in a sloping to steep

dissected shale plains landscape setting, which is typically composed of

stream breaklands. Parent materials are residuum and colluvium underlain by

siltstones and claystones.

Accessory Characteristics: The primary soils are shallow to deep, with medium

to very gravelly medium textures. The vegetation is a mosaic of prairie

grasslands and coniferous forest. Mean annual precipitation ranges from 31 to

51 cms (12 to 20 inches). The elevation range is 760 to 915 meters (2500 to

3000 feet). The dominant slopes have gradients greater than 25 percent. This

unit is strongly dissected by streams, with the dominant stream pattern being

dendritic and parallel.

LTA Components: This landtype association consists of stream breaks.

Stream breaks are formed in loamy residuum, and colluvium. Slope gradients

range from 15 to 60 percent. Soils in these landforms are shallow to deep,

moderately developed, with medium and medium to very gravelly medium textures.

These soils are classified as Typic Haploborolls, Lithic Ustorthents, Typic

Ustorthents, and Ustic Torriorthents. Rock outcrop occurs on about 20 percent

of this landscape component. The dominant potential natural vegetation is big

sagebrush, shadscale, skunkbrush, rocky mountain juniper, green ash, ponderosa

pine, needle and thread, western wheatgrass, little bluestem and horizontal

juniper. This component represents 100 percent of this unit.

Compiled by: John R. Lane, Custer National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 468
Section M331B Bighorn Mountains

Section 342A Bighorn Basin

This Section occurs in southcentral Montana and northcentral Wyoming. Only the

Pryor Mountains, the northern portion of the Bighorn Mountains, are in the

Northern Region. These mountains consist mainly of limestones and shales.

Included with this Section is a small acreage in the Bighorn Basin (Section

342A). Due to the scale differences between the Section and LTA mapping, some

LTAs mapped in M331B have acreage shown in 342A.

LTA27-M331B

LTA27-342A

BREAKS: CARBONATES

Location: This unit is located mostly in the Pryor Mountains of south central

Montana on the Custer National Forest.

 Acreage by Section

 27-M331B 21,388

 27-342A 1,069

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a dissected mountain

landscape setting, which is typically composed of structural and stream

breaks. Parent materials are residuum, and colluvium underlain by limestone

and shale.

Accessory Characteristics: The primary soils are shallow to deep, with medium

to gravelly medium and moderately fine textures. The vegetation is a mosaic of

coniferous forest and mountain grassland. Mean annual precipitation ranges

from 38 to 51 cms (15 to 20 inches). The elevation range is 1500 to 2700

meters (4920 to 8860 feet). The dominant slopes have gradients of 15 to >90

percent. This unit is moderately dissected by streams with the dominant stream

pattern being dendritic.

LTA Components: This landtype association consists of structural breaks and

stream breaks.

Structural breaks are formed in residuum and colluvium. Slope gradients range

from 45 to 90 percent. Soils on these landforms are shallow to deep, weakly to

strongly developed, medium to very gravelly medium textures and rock outcrop.

These soils are classified as Calcic Cryoborolls, Typic Cryoboralfs, and Typic

Cryoborolls. Rock outcrop occurs on about 30 percent of this landscape

component. The dominant potential natural vegetation includes subalpine fir,

Douglas-fir, and Engelmann spruce. This component represents 60 percent of

this unit.

Stream breaks are formed in colluvium and residuum. Slope gradients range from

15 to greater than 90 percent. Soils on these landforms are shallow to deep,

weakly to strongly developed, medium to gravelly medium textures and rock

outcrop. These soils are classified as Lithic Cryoborolls, Calcic Cryoborolls,

and Typic Cryoboralfs. Rock outcrop occurs on about 40 percent of this

landscape component. The dominant potential natural vegetation includes

subalpine fir, Douglas-fir, and Engelmann spruce, and Idaho fescue and prairie

smoke. This component represents 40 percent of this unit.

Compiled by: John R. Lane, Custer National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 469
LTA66-M331B

LTA66-342A

MOUNTAIN SLOPES AND RIDGES: CARBONATES

Location: This unit is located mostly in the Pryor Mountains of south central

Montana on the Custer National Forest.

 Acreage by Section

 66-M331B 52,103

 66-342A 2,524

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a mountain landscape

setting dissected by streams, which is typically composed of mountain

dipslopes, benches, and ridges. Parent materials are gravelly and cobbly

alluvium and colluvium, and channery and gravelly residuum underlain by

Madison limestone. 

Accessory Characteristics: The primary soils are shallow to deep, with medium

and fine textures. The vegetation is a mosaic of shrublands, and mountain

grasslands. Mean annual precipitation ranges from 38 to 48 cms (15 to 19

inches). The elevation range is 1160 to 2713 meters (3800 to 8900 feet). The

dominant slopes have gradients of 4 to 45 percent. This unit is moderately to

strongly dissected by streams with the dominant stream pattern being

dendritic.

LTA Components: This landtype association consists of dipslopes, benches, and

ridges.

Dipslopes are formed in colluvial and residual limestone and sandstone. Slope

gradients range from 8 to 70 percent. Soils on these landforms are shallow to

deep, weakly to strongly developed, medium and gravelly medium textures. 

These soils are classified as Lithic, Calcic, Typic and Vertic Cryoborolls. 

Rock outcrop occurs on about 10 percent of this landscape component. The

dominant potential natural vegetation includes big sagebrush and Idaho fescue

for the non-forested areas and Douglas-fir, and limber pine for the forested

areas. This component represents 70 percent of this unit.

Benches are formed in colluvial, residual and alluvial limestone and sandstone

materials. Slope gradients range from 2 to 25 percent. Soils on these

landforms are shallow to deep, moderately to strongly developed with medium

and gravelly medium textures. These soils are classified as Ustollic

Calciorthids, and Typic Ustorthents. Rock outcrop occurs on about 10 percent

of this landscape component. The dominant potential natural vegetation is

mountain sagebrush, Idaho fescue, and Douglas-fir. This component represents

about 15 percent of this unit.

Ridges are formed in residuum. Slope gradients range from 8 to 25 percent.

Some of these ridges at the higher elevations exhibit frost churned features.

Soils on these landforms are shallow to deep, poorly to strongly developed,

with medium to very gravelly moderately fine textures. These soils are

classified as Lithic Cryoborolls, Calcic Cryoborolls, and Vertic Cryoborolls.

Rock outcrop occurs on about 10 percent of this landscape component. The

dominant potential natural vegetation is big sagebrush, Idaho fescue, and

alpine fir. This component represents about 15 percent of this unit.

Compiled by: John R. Lane, Custer National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 470
LTA92-M331B

COLLUVIAL SLOPES: MIXED GEOLOGY

Location: This unit is located in the Pryor Mountains of south central Montana

on the Custer National Forest.

 Acreage by Section

 92-M331B 879

LTA Setting and General Characteristics

Differentiating Characteristics: This map unit occurs in a dissected mountain

landscape setting, which is typically composed of mountain footslopes and

landslide deposits. Parent materials are residuum, colluvium and landslide

deposits underlain by shale, limestone and sandstone.

Accessory Characteristics: The primary soils are shallow to deep, with

channery to stony medium and moderately fine textures. The vegetation is a

mosaic of coniferous forest, shrublands and mountain grasslands. Mean annual

precipitation ranges from 15 to 51 cms (6 to 20 inches). The elevation range

is 1300 to 2000 meters (4260 to 6560 feet). The dominant slopes have gradients

of 15 to greater than 45 percent. This unit is moderately dissected by

streams, with the dominant stream pattern being dendritic.

LTA Components: This landtype association consists of mountain footslopes and

landslide deposits.

Mountain footslopes are formed in residuum and colluvium. Slope gradients

range from 15 to greater than 45 percent. Soils on these landforms are shallow

to deep, weakly to strongly developed, with medium to gravelly medium

textures. These soils are classified as Calcic Cryoborolls, Lithic

Calciborolls, and rock outcrop. Rock outcrop occurs on about 20 percent of

this landscape component. The dominant potential natural vegetation includes

shrubby cinquefoil and king fescue. This component represents 70 percent of

this unit.

Landslide deposits are formed in shale and limestone. Slope gradients range

from 15 to greater than 45 percent. Soils on these landforms are shallow to

deep, weakly to strongly developed, with gravelly to stony medium textures.

These soils are classified as rock outcrop, Lithic Cryoborolls, Calcic

Cryoborolls, Typic Cryoborolls, and Typic Cryoboralfs. Rock outcrop occurs on

about 10 percent of this landscape component. The dominant potential natural

vegetation includes Idaho fescue, western wheatgrass and Douglas-fir. This

component represents 30 percent of this unit.

Compiled by: John R. Lane, Custer National Forest

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 471
Appendix A

THE NATIONAL HIERARCHY OF ECOLOGICAL UNITS

This LTA mapping report refers to several levels of the National Hierarchical

Framework of Ecological Units (ECOMAP 1993): Sections, Subsections, Landtype

Associations and Landtypes. To help the reader understand these levels the

following is an excerpt from the 1993 paper. Readers wanting more information

and the references for the paper should consult that document.

The National Hierarchical Framework of Ecological Units is a regionalization,

classification and mapping system that provides a systematic method for

classifying and mapping areas of the Earth based on associations of ecological

factors at different geographic scales.

Ecological types are classified and ecological units are mapped based on

associations of those biotic and environmental factors that directly affect or

indirectly express energy, moisture, and nutrient gradients which regulate the

structure and function of ecosystems. These factors include climate,

physiography, water, soils, air, hydrology, and potential natural communities.

Ecological unit maps can be coupled with inventories of existing vegetation,

air quality, aquatic systems, wildlife, and human elements to characterize

complexes of life and environment, or ecosystems.

Ecological Unit Design

The primary purpose for delineating ecological units is to display land and

water areas at different levels of resolution that have similar capabilities

and potentials for management. Ecological Units are designed to exhibit

similar patterns in: (1) potential natural communities, (2) soils, (3)

hydrologic function, (4) landform and topography, (5) lithology, (6) climate,

(7) air quality and (8) natural processes for cycling plant biomass and

nutrients (e.g. succession, productivity, fire regimes).

Climate, as modified by topography, is the dominant criteria at the upper

levels of the hierarchy. Other factors, such as geomorphic process, soils and

potential natural communities take on equal or greater importance than climate

at lower levels.

Underlying principles

Ecosystems exist at many spatial scales, from the global ecosphere down to

regions of microbial activity. The level of discernible detail, the number of

factors comprising ecosystems, and the number of variables used to

characterize these factors progressively increase at finer scales. Hence the

data and analysis requirements, and investments for ecosystem classification

and mapping also increase for finer scaled activities.

The structure and function of ecosystems are largely regulated along energy,

moisture, nutrient, and disturbance gradients. These gradients are affected by

climate, physiography, soils, hydrology, flora, and fauna. While the

association of these factors is all important in defining ecosystems, all

factors are not equally important at all spatial scales. At coarse scales, the

important factors are largely abiotic, while at finer scales both biotic and

abiotic factors are important. Ecosystems are conceptualized as occurring in a

nested geographic arrangement, with many smaller ecosystems embedded in larger

ones.

At global, continental, and regional scales, ecosystem patterns correspond

with climatic regions, which change mainly due to latitudinal, orographic, and

maritime influences. Within climatic regions, physiography or landforms

modify macroclimate, and affect the movement of organisms, the flow and

orientation of watersheds, and the frequency and spatial pattern of

disturbance by fire and wind. Within climatic -physiographic regions, water,

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 472
plants, animals, soils, and topography interact to form ecosystems at Land

Unit scales.

Classification Framework

The following is an overview of the differentiating criteria used in the

development of the ecological units.

Ecoregion: At the Ecoregion scale, ecological units are recognized by

differences in global, continental, and regional climatic regimes and gross

physiography. The basic assumption is that climate governs energy and moisture

gradients, thereby acting as the primary control over more localized

ecosystems. Three levels of Ecoregions are identified in the hierarchy:

domains, divisions and provinces. Each LTA includes the domain, division and

province modifier as a label attribute. The reference (ECOMAP, 1993) can be

consulted for details about these levels.

Subregion: Subregions are characterized by combinations of climate,

geomorphic process, topography, and stratigraphy that influence moisture

availability and exposure to radiant solar energy, which in turn directly

control hydrologic function, soil -forming processes, and potential plant

community distributions. Sections and Subsections are the two ecological units

mapped at this scale.

Section: Broad areas of similar geomorphic process, stratigraphy, geologic

origin, drainage networks, topography, and regional climate. Such areas are

often inferred by relating geologic maps to potential natural vegetation

"series" groupings. Boundaries of some Sections approximate geomorphic

provinces as recognized by geologists. Section names generally describe the

predominant physiographic feature upon which the ecological unit delineation

is based, such as Idaho Batholith, Yellowstone Highlands and Northern Rockies.

In the Northern Region these units were mapped at a scale of 1:1,000,000

Subsections: Smaller areas of Sections with similar surficial geology,

lithology, geomorphic process, soil groups, subregional climate, and potential

natural communities. Names of Subsections are usually derived from geologic

features, such as Upper Yellowstone Valley, Montana Glaciated Plains, and

Clearwater Mountains and Breaks. Mapping of these units was done at a scale of

1:500,000.

Landscape Scale: At the Landscape scale, ecological units are defined by

general topography, geomorphic process, surficial geology, soil and potential

natural community patterns and local climate. These factors affect biotic

distributions, hydrologic function, natural disturbance regimes and general

land use. Local landform patterns become apparent at this level in the

hierarchy, and differences among units are usually obvious to on -the-ground

observers. At this level, terrestrial features and processes may also have a

strong influence on ecological characteristics of aquatic habitats. Landtype

Association ecological units represent this scale in the hierarchy.

Landtype Associations: Groupings of Landtypes or subdivisions of

Subsections based upon similarities in geomorphic process, geologic rock

types, soil complexes, stream types, lakes, wetlands, and series, subseries,

or plant association vegetation communities. A number of different groupings

of landtypes or subdivisions of Subsections are possible depending upon the

purpose of the landtype associations. At the Landtype Association level

predictable and repeatable units are mapped, using the delineation criteria

that best fits the interpretive need. Region 1 chose to first develop a

consistent set of geomorphic LTAs for the purpose of providing essential data

needed in watershed characterization and planning. Names of Landtype

Associations, as mapped in the Northern Region are combinations of landforms

and geologic materials, such as Steep Glaciated Lands: Granitics.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 473
Land Unit Scale: At the basic Land Unit scale, ecological units are designed

and mapped in the field based on properties of local topography, rock types,

soils, and vegetation. These factors influence the structure and composition

of plant communities, hydrologic function, and basic land capability.

Landtypes and Landtype Phases are the ecological units mapped at this scale.

Landtypes: Subdivisions of Landtype Associations or groupings of Landtype

Phases based on similarities in soils, landform, rock type, geomorphic

process and plant associations. The form of land surfaces influence hydrologic

function (e.g., drainage density, dissection relief) and therefore are often

used to delineate different landtypes in mountainous terrain. In the Northern

Region landtype mapping has been done at a scale of 1:24,000 and corresponds

with Order III NCSS Soil Survey information.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 474
Appendix B

GEOMORPHIC OVERVIEW OF THE NORTHERN REGION

The repeatable patterns of landtype associations occur across a large complex

of landscapes which includes portions of both the Rocky Mountains and the

Great Plains. While the focus of this report is on the mapping of landtype

associations, it is useful to first obtain a "big picture" perspective of the

geomorphic units that are distinct at the regional scale. These landscape

settings are characterized using the same types of criteria (landforms and

geologic materials) as the landtype associations, however they are much

larger, distinct geographic units.

Listed below are brief descriptions for the following seventeen distinct

geomorphic environments found in the Northern Region (see Figure 82). The

descriptions emphasize the geologic processes which have created these areas

and the landforms and geologic materials occurring in each.

 Pryor Mountains

 Yellowstone Volcanic Plateau

 Beartooth Plateau

 Non Glaciated Plains

 Northern Glaciated Plains

 Rocky Mountain/Beartooth Front

 Central Montana Island Mountains

 Southwest Montana Mountains and Valleys

 Alpine Glaciated Metasedimentary Mountains

 Continental Glaciated Mountains

 Metasedimentary Mountains

 Columbia River Basalts

 Idaho Batholith Uplands

 Idaho Canyon Lands

 Badlands and Breaklands

 Prairie Potholes

 Red River Valley

Pryor Mountains

The Pryors are the northern nose of the Bighorn mountains of Wyoming. They are

cut off by the antecedent gorge of the Bighorn River. Structural features

include similar block faulting in a broad gentle uplift with minimal

deformation on top with steeply dipping sediments draped up the sides. There

is an east-west fault that divides the Pryors into two styles of landscape. 

To the north, the Cretaceous sediments are exposed in rolling hills of

bentonitic shales with some areas of badlands. To the south, the massive

Paleozoic limestones dominate the landscapes with high cliffs and large steep

walled canyons.

Yellowstone Volcanic Plateau

The Yellowstone Volcanic plateau is a complex landscape shaped by glaciation

and dominated by three main geologic types. The ash -dominated volcanics result

in rolling, rounded landforms with few outcrops. Where oversteepened by

glaciation or erosion they are very slide prone and indeed there are numerous

very large slides in this material. The flow dominated volcanics are rockier

and in many areas very susceptible to glacial plucking in the cirques,

resulting in large amphitheater -like cirques at drainage heads. The Archean

rocks preserve the "ice just melted look " ,resulting in rugged, spectacular

landscapes with numerous horns and aretes.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 475
Beartooth Plateau

This landscape is defined by fault blocks that raise it to the highest average

elevation in the region. The core of the plateau is very resistant old rocks

dated at 4 billion years. There are a few places where the overlying

sedimentary rocks can still be seen. There are large areas in the southwest

where ash dominated volcanics cover these old rocks. A special case is the

Stillwater Complex which outcrops along the northern front. This is a layered

intrusive body of unusually mafic rocks that host the only U.S. platinum group

metal mines. Joint control of drainages and lakes at intersections is very

dominant in the portions underlain by crystalline rocks. Many of these were

enlarged in spectacular fashion by glaciation. Indeed a few small glaciers

remain in this landscape. Grasshopper Glacier indicates that as late as 300

years ago there were swarms of locusts at this elevation in late summer.

Another feature of note are the various "plateaus" or high elevation erosional

surfaces preserved. These large broad ridgetops at high altitude show examples

of most types of glacial and periglacial landforms. Till and talus are very

abundant. The horns and cirques in this very resistant terrain give it a raw,

just exposed appearance that is fresh from the last ice age.

Non Glaciated Plains

The Non-glaciated Plains are the southern, unglaciated component of the

Northern Great Plains. They are characterized by low relief and gently rolling

grasslands. The bedrock is Cretaceous marine shale and Tertiary fluvial

sediments, with some large sandstone units scattered throughout. The other

parent material from which soils have developed is loess. Lesser areas

dominated by benches topped with lag gravel deposits are fragments of former

landscape surfaces. The clinker beds or "scoria" from burnt coal seams form

colorful resistant beds in the Tertiary outcrops.

Northern Glaciated Plains

A dominant component of the northern Great Plains, this is a large expanse of

prairie with scattered highlands extending above the low relief landscape.

This area was overrun by continental glaciers and covered with glacial drift

to depths of up to 100 feet. The glacial drift is a mixture of clay to boulder

size material. Receding glacial ice also left the distinctive pot and kettle

topography of rolling hills with ponds and lakes. Ice damming of the major

rivers also deposited areas of lacustrine and delta sediments. Glacial drift

is the parent material for many of the Great Plains soils and is markedly

different than the Cretaceous marine shales on the rest of the prairie. The

Glaciated and Nonglaciated Plains landscapes share commonality in having soils

with a distinctive loess component, and the lag gravel remnants of former

landscape surfaces on ridge tops and benches.

Rocky Mountain/Beartooth Front

The uplift and thrust faulting that created the Rocky Mountains also resulted

in steeply dipping faults along the slopes that face the prairies. The uplift

and thrust faulting also pushed the overlying sedimentary rocks into steep dip

slopes. In places slopes were too steep to resist the forces of gravity, and

large slabs of this rock telescoped by sliding into the low spots in a series

of thrust faults. This pile of over thrust and wrinkled rocks are the Mountain

Fronts. Near the mountains the sedimentary rocks drape up against the uplifted

mountains in steep flatirons on the noses of ridges. Further out, the

landscape becomes more gentle and rolling or becomes a series of hogbacks

parallel to the mountains. The valleys contain large amounts of outwash gravel

often displayed in multiple terraces that give insight into climatic change

and hydrologic variation of the last 10,000 years.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 476
Central Montana Island Mountains

The Central Montana Island Mountains occur as widely separated uplifts rising

above, and isolated by the surrounding prairie. These mountains are of varied

geologic types ranging from volcanic piles with an intrusion in the middle, to

uplifted sediments with an intrusion in the middle. At higher elevations the

mountains have been glaciated.

Southwest Montana Mountains and Valleys

The dominant features of these landscapes are mountains separated by large,

gravel-filled valleys These large basins dominate the lower elevations. The

mountains are complex landforms that include a number of rock types and

formative processes, including batholiths and alpine glaciation. The valleys

or basins are similar in being broad areas filled with Tertiary sediments and

Quaternary gravels. They are commonly linked to other basins along shared

rivers and are separated from other basins and landscapes by gorges. The

mountains have some general similarities in being sedimentary piles that were

uplifted and faulted, with granitic intrusions in core areas. A wide variety

of lithologies and ages are thus exposed by erosion. Higher elevations

commonly show characteristics of alpine glaciation.

Alpine Glaciated Metasedimentary Mountains

In these environments, the Metasedimentary Mountain landscapes were modified

by pervasive alpine glaciation. Large U-shaped valleys with extensive rock

outcrop run up to rugged cirques surrounded by craggy shattered peaks. Talus

is abundant on slopes, with till, outwash and morainal deposits in the

valleys. The deposits of periglacial processes are widespread. Lakes from

mechanisms such as pot and kettle, damming by moraines, mass movement, or

talus ramparts and cirque lakes are common.

Continental Glaciated Belt Mountains

This landscape setting is made distinctive by the rounding of landforms by

continental glaciation. The glacial activity scoured the ridgetops and

deposited till on the sideslopes and valley bottoms. These deposits are often

50 to 100 feet thick. Some characteristics remain from the parent Belt Basin

landscape but these are heavily modified by glacial action and the addition of

till and glacial lake sediments in lower areas. Most of this area retains the

mantle of loess and ash on top of the glacial material. The valley deposits

are various mixes of till, moraine, outwash and lake deposits- reflecting

their recent history of ice damming, diversion, flooding, stagnant or receding

ice features such as pot and kettle; and some unique features from

catastrophic lake releases, jokulhaups.

Metasedimentary Mountains

In these environments the Belt rocks are lightly metamorphosed quartzite and

argillite that are resistant to weathering. In some areas thick carbonate

units of dirty limestone, and limestone cemented sediments are also present.

The characteristic landforms are large steep slopes in an incised landscape of

V-shaped valleys. The loess/ash component is typically missing or greatly

reduced on the lower slopes. Talus is common on the lower slopes often

extending up to rock outcrop on valley sides. On the northerly aspects the

talus often extends upslope and goes under vegetative cover. The larger

valleys show evidence of modification by damming from ice and lake sediments,

then the resulting erosion and redeposition from catastrophic draining of the

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 477
lake. Long stretches of canyons have been stripped to bedrock to about 1000

feet up the valley sides leaving very rocky slopes dominated by talus and

outcrop. In these areas soils are largely mixtures of colluvium and loess, and

are shallow to bedrock. Likewise, large areas of the valley bottoms are

lakebeds. The outwash gravels from these events make up the "bowling ball"

acquifers that are unique in their water transmission rates and susceptibility

to contamination. The major river of the area follows the Lewis and Clark

line-the major structural feature. Tributary valleys correspond generally with

secondary structural orientations defined by the edges of the overthrust

plates.

Columbia River Basalts

This landscape is the result of the Columbia River Basalts flooding

pre-existing terrain to about 3400 feet in elevation. The basalts filled

drainage basins and overtopped low ridges, isolating the mountain tops. This

produced low relief plateaus and rolling hills dotted with steptoes, the tops

of the previous mountains.

The eastern edges of the flooded uplands in Idaho are a mix of lacustrine and

stream deposits lying upon, and interbedded with, the basalt flows. Most of

these edge flows are invasive basalts that were formed by the denser basalt

invading the soft, wet sediments that form the interbeds. The interbeds are

not continuous layers, rather they are isolated pockets formed by the damming

of ancestral rivers as the basalt flowed up valley. Some were formed by

overbank muds, some are lake and pond deposits, and some are channel deposits

of sand and gravel. Topographically, the interbeds are expressed by

esplanades, (slope breaks or gentle benches), among the cliffs that mark the

basalt flows along the canyons. Where the Big Canyon landscapes cut through

this landscape the basalts are very unstable and susceptible to all forms of

mass wasting. 

Idaho Batholith Uplands

The distinctive influence of the granitic parent materials on hydrology,

soils, and landforms define this environment. The Idaho Batholith uplands are

an expansive, contiguous uplifted area characterized by large rounded mountain

masses and basin areas with little rock outcrop. Soils are derived from gruss

and loess/ash. This landscape is further modified by the Big Canyon landscape.

In areas where cutting by the big canyons occurred, the loess and ash

component of soils are typically missing. Another variation may be glaciation,

which occurs at higher elevations. Glacially scoured areas have the typical

glacial valley U-shapes with exposed rock in the walls. Ridgetops can be

either sharp and rocky or gentle wide forms dominated by periglacial

processes.

Idaho Canyon Lands

This setting is dominated by the deep entrenchment of the major trunk streams

into uplifted highlands. These large canyons penetrate deeply into a number of

other landscapes causing rapid changes in a number of ecological variables.

Steep, high relief breaks and narrow valley bottoms are characteristic

features. The loess/ash components of soils common to adjacent hills are

typically missing from these high energy slopes. These canyons sliced through

a number of rock types with little regard for lithologic variationsemphasizing the overpowering nature of the process of downcutting in these

landscapes. A variety of mass wasting processes are active in this

environment. Where the Big Canyons cut through the Basalt Flooded Uplands very

large slides and failures are common.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 478
Badlands and Breaks

The Badlands are areas of thinly bedded shales and sandstones. They occur in

the plains areas and are areas of accelerated erosion. The factors common to

these areas are alternating beds of softer and harder materials with the

softer material being impervious material such as clay, near horizontal

bedding, and high density intricate drainage patterns. The larger areas have

high internal relief but the landform is cut into the surrounding plains or

plateau areas. They are a good example of a self -enhancing feedback mechanism.

The breaks are the same type of features that occur along river courses

incised into the surrounding plains.

Prairie Potholes

This landscape is a glaciated prairie which is often quite flat but does

contain large numbers of shallow pothole lakes and ponds. The surface is

glacial till often with a layer of loess on top. The soils are similar to the

glaciated plains but there are larger areas of gravelly, bouldery soils. The

striking difference is the pot holes and stagnant ice features related to

drainage of water from the ice.

Red River Valley

This landscape is composed of the bottom and shorelines of Lake Agassiz as

modified by the last 9000 years. The small relief present was created by the

old beach terraces and entrenchment of streams into the lake bottom and delta

sediments along with some wind movement of loose sediments, primarily silt and

sand. Up to 30 meters of glacial rebound are known from elevation differences

in beach levels from north to south with the north being higher. Streams are

low gradient, and are often meandering. Just below the lake sediments are a

complex of till and peat layers. Many areas have high groundwater associated

with these layers that maintain numerous ponds. The grasslands are in the

Sheyenne Delta where the river emptied into the lake and made more of a water

covered fan than a delta. The wind has mobilized the sands into dunes that are

partially stabilized by vegetation.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 479
Appendix C

ACREAGE BY LANDFORM GROUP

LANDFORMS ACRES

Badlands 783,785

Breaks 4,373,721

Breaks, moderately weathered 250,194

Colluvial deposits 23,748

Dissected breaks 317,175

Dissected plains 569,653

Eroded uplands 306,749

Glaciated dissected plains 27,111

Glacio-lacustrine plains 47,411

Glaciated mountain slopes 6,405,843

Glaciated mountain slopes and ridges 210,199

Glaciated plains 32,403

Hills and dunes 75,822

Hills and plateaus 964,967

High relief mountain slopes 408,452

Low relief hills, highly weathered 339,903

Low relief hills, moderately weathered 199,921

Low relief hills 2,185,790

Mountain ridgetops, frost-shattered 2,163,708

Mountain slopes and ridges 9,109,010

Mountain slopes and ridges, moderately weathered 139,119

Mass wasted slopes 524,977

Pediments 30,516

Plains 968,187

Plateaus and buttes 184,761

Glacial troughs and trough walls 161,845

Valleys 4,070,417

Water 443,840

Total Acres 40,392,207

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 480
Appendix D

ACREAGE BY GEOLOGIC MATERIAL

GEOLOGIC MATERIAL ACRES

Alluvium 3,075,753

Deltaic sediments 47,411

Gneiss, schist 2,961,719

Granitics 3,339,310

Granitics, highly weathered 1,588,217

Granitics, weakly weathered 1,301,513

Lacustrine sediments 994,663

Loess 964,967

Mixed 579,241

Metasediments 14,175,759

Metasedimentary glacial till 184,540

Quartzite, calc-silicates 241,183

Carbonates 1,456,348

Shale, siltstone, sandstone 2,872,651

Soft sedimentary 90,110

Sandstone, shale 2,238,884

Tertiary sediments 976,556

Volcanics 2,745,322

Wind transported sediments 75,822

Water 443,840

Total acreage 40,392,207

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 481
Appendix E

 ACREAGE OF LANDTYPE ASSOCIATIONS

 FOR ENTIRE MAPPING AREA

LTA ACRES 

1 968,190

2 32,403

3 569,655 

4 27,112

5 783,788

6 306,750

7 184,762

8 47,411

9 75,822

10 924,419

11 994,667

12 1,624,460

13 27,211

14 499,654

17 964,971

20 1,862,824

21 352,055

22 374,677

23 411,720

24 680,456

25 239,915

26 250,195

27 435,331

28 317,176

29 16,756

34 173,106

35 48,360

36 108,526

37 126,821

39 233,061

40 2,844,711

41 1,135,099

42 113,800

43 301,373

44 406,544

45 161,839

46 74,315

47 87,530

50 4,076,840

51 1,268,658

53 410,776

54 180,107

57 284,944

59 139,119

60 3,832,100

61 890,980

62 601,787

63 861,405

64 1,148,177

65 90,110

66 592,827

67 120,574

68 971,083

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 482
69 30,516

70 1,014,993

71 344,681

72 325,053

73 80,001

74 102,036

75 55,493

77 241,456

80 139,639

81 699,916

82 369,682

83 953,882

84 339,904

85 199,922

88 22,697

90 524,979

92 23,748

99 443,842

________________________

71 LTAs 40,392,207

 ACRES MAPPED 

 

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 483
Appendix F

ACREAGE AND PROPORTIONATE EXTENT OF

LANDTYPE ASSOCIATIONS BY SECTIONS

SECTION 331A

PALOUSE PRAIRIE

 Acres % of % of

LTA Mapped Mapped Section

10 11,034 0.6 0.3

12 4,482 0.2 0.1

14 20,245 1.1 0.6

17 855,787 45.1 26.4

23 6,961 0.4 0.2

24 210,704 11.1 6.5

59 2,670 0.1 0.1

60 79,294 4.2 2.4

61 3,272 0.2 0.1

62 1,073 0.1 0.0

63 7,634 0.4 0.2

64 263,297 13.9 8.1

80 11,266 0.6 0.3

81 425 0.0 0.0

82 223,530 11.8 6.9

83 167,138 8.8 5.2

84 24,608 1.3 0.8

85 101 0.0 0.0

90 2,621 0.1 0.1

99 1 0.0 0.0

__________________________________________________________

 58.4

19 LTAs 1,896,169

 ACRES MAPPED 

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 484
SECTION 331D

NORTHWESTERN GLACIATED PLAINS

 Acres % of % of

LTA Mapped Mapped Section

10 982 1.9 0.0

27 148 0.3 0.0

34 6,622 13.2 0.03

36 764 1.5 0.0

43 624 1.2 0.0

44 98 0.2 0.0

53 3,058 6.1 0.0

64 26,813 53.4 0.1

68 8,549 17.0 0.08

90 2,576 5.1 0.0

_______________________________________________________ 

 

 0.2

10 LTAs 50,241

 ACRES MAPPED 

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 485
SECTION 331F

NORTHWESTERN GREAT PLAINS

 Acres % of % of

LTA Mapped Mapped Section

1 946,770 34.0 3.6

2 32,403 1.2 0.1

3 516,063 18.8 1.9

4 27,111 1.0 0.1

5 783,355 28.6 2.9

6 116,337 4.2 0.4

7 22,819 0.8 0.1

10 5,917 0.2 0.0

12 50,872 2.0 0.2

14 206,152 7.5 0.8

25 25,390 0.9 0.1

99 5,699 0.2 0.0

_________________________________________________________

 13.6

11 LTAs 2,738,893 

 ACRES MAPPED

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 486
SECTION 331G

POWDER RIVER BASIN

 Acres % of % of

LTA Mapped Mapped Section

1 21,416 4.2 0.1

3 53,589 10.6 0.2

5 429 0.1 0.0

6 190,412 37.7 0.8

7 161,941 32.1 0.7

14 27,147 5.4 0.1

25 50,254 9.9 0.2

________________________________________________________

 2.25

7 LTAs 505,191

 ACRES MAPPED

 

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 487
SECTION M331A

YELLOWSTONE HIGHLANDS

 Acres % of % of

LTA Mapped Mapped Section

10 44,009 2.5 0.7

12 59,997 3.4 1.0

14 12,271 0.7 0.2

23 25,213 1.4 0.4

25 69,798 4.0 1.1

27 6,506 0.4 0.1

34 93,405 5.3 1.5

36 75,189 4.3 1.2

37 33,733 1.9 0.5

39 150,081 8.5 2.4

40 626 0.0 0.0

41 117,326 6.7 1.9

42 60,666 3.4 1.0

43 42,458 2.4 0.7

44 17,976 1.0 0.3

51 760 0.0 0.0

53 76,853 4.4 1.2

54 87,011 4.9 1.4

57 177,582 10.1 2.9

62 15,110 0.9 0.2

63 179,717 10.2 2.9

64 21,460 1.2 0.3

68 152,581 8.7 2.5

69 412 0.0 0.0

72 25,079 1.4 0.4

73 16,886 1.0 0.3

74 10,729 0.6 0.2

77 62,911 3.6 1.0

90 113,376 6.4 1.8

99 13,557 0.8 0.2

_______________________________________________________

 28.4

30 LTAS 1,763,291

 ACRES MAPPED

 

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 488
SECTION M331B

BIG HORN MOUNTAINS

 Acres % of % of

LTA Mapped Mapped Section

27 21,388 28.8 3.2

66 52,103 70.1 7.9

92 879 1.2 0.1

_______________________________________________________

 11.2

3 LTAS 74,370 

 ACRES MAPPED

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 489
SECTION M332A

IDAHO BATHOLITH

 Acres % of % of

LTA Mapped Mapped Section

10 9,581 0.3 0.2

12 10,308 0.3 0.3

14 8,100 0.3 0.2

17 30 0.0 0.0

20 8,070 0.3 0.2

21 209,877 6.6 5.4

22 283,624 9.0 7.3

23 129,732 4.1 3.3

24 11,592 0.4 0.3

26 215,922 6.8 5.6

29 10,532 0.3 0.3

39 42,652 1.3 1.1

40 4,756 0.2 0.1

41 401,415 12.7 10.3

45 71,071 2.2 1.8

46 35,567 1.1 0.9

47 6,809 0.2 0.2

51 281,987 8.9 7.3

57 54,631 1.7 1.4

59 129,742 4.1 3.3

60 63,800 2.0 1.6

61 95,759 3.0 2.5

62 129,836 4.1 3.3

63 96,467 3.1 2.5

64 18,316 0.6 0.5

70 1,385 0.0 0.0

71 62,411 2.0 1.6

72 177,263 5.6 4.6

73 4,171 0.1 0.1

77 159,797 5.1 4.1

80 1,243 0.0 0.0

81 139,140 4.4 3.6

82 26,996 0.9 0.7

83 27,852 0.9 0.7

84 20,976 0.7 0.5

85 180,023 5.7 4.6

90 29,413 0.9 0.8

_____________________________________________________

 81.3

37 LTAS 3,160,073 

 ACRES MAPPED

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 490
SECTION M332B

BITTERROOT VALLEY

 Acres % of % of

LTA Mapped Mapped Section

10 201,963 4.1 4.1

11 117,468 2.4 2.4

12 292,138 5.9 5.9

14 33,479 0.7 0.7

20 360,304 7.2 7.2

21 18,000 0.4 0.4

22 59,119 1.2 1.2

23 100 0.0 0.0

24 14,377 0.3 0.3

25 13,741 0.3 0.3

27 9,864 0.2 0.2

29 5,637 0.1 0.1

34 46,982 0.9 0.9

35 27,907 0.6 0.6

37 6,635 0.1 0.1

40 401,649 8.1 8.1

41 338,618 6.8 6.8

43 77,618 1.6 1.6

44 18,787 0.4 0.4

45 83,690 1.7 1.7

47 3,765 0.1 0.1

50 312,518 6.3 6.3

51 197,817 4.0 4.0

53 6,924 0.1 0.1

54 18 0.0 0.0

57 9,352 0.2 0.2

60 767,352 15.4 15.4

61 92,627 1.9 1.9

62 152,086 3.1 3.1

63 5,513 0.1 0.1

64 123,770 2.5 2.5

65 30,430 0.6 0.6

66 78,732 1.6 1.6

67 72,462 1.5 1.5

68 84,764 1.7 1.7

70 137,464 2.8 2.8

71 17,693 0.4 0.4

72 94,500 1.9 1.9

73 15,223 0.3 0.3

74 6,424 0.1 0.1

75 15,252 0.3 0.3

80 4,765 0.1 0.1

81 105,939 2.1 2.1

82 10,401 0.2 0.2

83 295,900 5.9 5.9

90 28,774 0.6 0.6

92 6,383 0.1 0.1

99 5,737 0.1 0.1

______________________________________________________ 

 100%

48 LTAS 4,983,813 

 ACRES MAPPED

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 491
SECTION M332C

ROCKY MOUNTAIN FRONT

 Acres % of % of

LTA Mapped Mapped Section

10 17,094 1.5 1.2

11 54 0.0 0.0

12 40,434 3.5 2.8

20 13,657 1.2 1.0

25 4,114 0.4 0.3

27 97,585 8.4 6.8

29 585 0.1 0.0

34 233 0.0 0.0

36 13,447 1.2 0.9

37 4,663 0.4 0.3

40 242,389 20.9 16.9

43 158,089 13.6 11.0

44 101,583 8.7 7.1

47 68 0.0 0.0

50 36,540 3.1 2.5

53 164,005 14.1 11.4

60 57,511 4.9 4.0

66 37,295 3.2 2.6

68 80,557 6.9 5.6

70 10,568 0.9 0.7

74 3,827 0.3 0.3

83 329 0.0 0.0

90 67,272 5.8 4.7

99 10,600 0.9 0.7

______________________________________________________

 81.6

22 LTAS 1,161,873 

 ACRES MAPPED

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 492
SECTION M332D

BELT MOUNTAINS

 Acres % of % of

LTA Mapped Mapped Section

10 86,889 2.9 0.9

12 68,706 2.3 0.7

14 2,606 0.1 0.0

20 13,713 0.5 0.1

21 8,423 0.3 0.1

24 4,485 0.2 0.0

25 20,570 0.7 0.2

27 235,563 8.0 2.5

34 15,602 0.5 0.2

36 12,477 0.4 0.1

37 46,990 1.6 0.5

39 5,300 0.2 0.1

40 7,828 0.3 0.1

41 100,346 3.4 1.1

42 23,865 0.8 0.3

43 12,878 0.4 0.1

44 15,947 0.5 0.2

50 5,840 0.2 0.1

51 98,809 3.3 1.1

53 10,191 0.3 0.1

54 45,449 1.5 0.5

57 569 0.0 0.0

60 310,782 10.5 3.4

61 251,536 8.5 2.7

62 88,948 3.0 1.0

63 149,345 5.0 1.6

64 197,349 6.7 2.1

65 42,266 1.4 0.5

66 379,757 12.8 4.1

67 41,037 1.4 0.4

68 336,244 11.4 3.6

70 419 0.0 0.0

72 3,365 0.1 0.0

73 23,449 0.8 0.3

74 859 0.0 0.0

75 36,716 1.2 0.4

77 78 0.0 0.0

81 106,587 3.6 1.2

82 13,249 0.4 0.1

83 95,156 3.2 1.0

90 73,847 2.5 0.8

92 12,928 0.4 0.1

99 451 0.0 0.0

_______________________________________________________

 

44 LTAS 2,958,890 ACRES MAPPED

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 493
SECTION M332E

BEAVERHEAD MOUNTAINS

 Acres % of % of

LTA Mapped Mapped Section

10 91,973 3.0 1.5

12 61,015 0.4 0.2

13 13,552 0.4 0.2

14 94,932 3.1 1.5

20 72,325 2.4 1.1

21 41,402 1.4 0.7

23 23,278 0.8 0.4

25 45,709 1.5 0.7

27 62,706 2.1 1.0

34 10,242 0.3 0.2

35 20,411 0.7 0.3

36 6,646 0.2 0.1

37 34,777 1.1 0.6

39 35,017 1.2 0.6

40 100,569 3.3 1.6

41 129,472 4.3 2.1

42 8,103 0.3 0.1

43 9,447 0.3 0.2

44 33,804 1.1 0.5

45 2,117 0.1 0.0

50 105,881 3.5 1.7

51 125,884 4.1 2.0

53 40,971 1.3 0.7

54 31,160 1.0 0.5

57 33,678 1.1 0.5

60 90,807 3.0 1.4

61 308,903 10.2 4.9

62 949 0.0 0.0

63 110,855 3.7 1.8

64 216,232 7.1 3.4

65 17,413 0.6 0.3

66 41,078 1.4 0.7

68 262,471 8.6 4.2

69 2,408 0.1 0.0

70 132,440 4.4 2.1

71 83,017 2.7 1.3

72 838 0.0 0.0

73 14,106 0.5 0.2

74 70,884 2.3 1.1

75 3,523 0.1 0.1

77 18,667 0.6 0.3

81 36,161 1.2 0.6

82 6,817 0.2 0.1

83 151,949 5.0 2.4

88 22,687 0.7 0.4

90 107,357 3.5 1.7

92 3,557 0.1 0.1

99 1,272 0.0 0.0 _____________________________________________________

 48.2

 

48 LTAS 3,036,244 

 ACRES MAPPED

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 494
SECTION M332G

BLUE MOUNTAINS

 Acres % of % of

LTA Mapped Mapped Section

10 433 0.1 0.0

12 5,193 0.7 0.4

17 9,801 1.3 0.7

22 18,597 2.5 1.4

24 420,518 56.8 31.2

26 29,535 4.0 2.2

42 21,164 2.9 1.6

51 1,459 0.2 0.1

54 16,458 2.2 1.2

59 6,706 0.9 0.5

62 2,305 0.3 0.2

64 133,556 18.0 9.9

72 433 0.1 0.0

73 6,159 0.8 0.5

82 44,956 6.1 3.3

90 23,333 3.1 1.7

______________________________________________________

 55.0

16 LTAS 740,615 

 ACRES MAPPED

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 495
SECTION M333A

OKANOGAN HIGHLANDS

 Acres % of % of

LTA Mapped Mapped Section

10 38,951 2.2 1.3

11 220,526 12.5 7.1

12 323,513 18.4 10.4

14 14,384 0.8 0.5

20 17,556 1.0 0.6

22 4,297 0.2 0.1

28 429 0.0 0.0

40 6,270 0.4 0.2

41 22,952 1.3 0.7

46 30,843 1.8 1.0

50 180,003 10.2 5.8

51 467,331 26.5 15.1

60 124,084 7.0 4.0

61 16,288 0.9 0.5

62 162,063 9.2 5.2

63 28 0.0 0.0

64 6,316 0.4 0.2

66 513 0.0 0.0

72 4,337 0.2 0.1

99 120,874 6.9 3.9

______________________________________________________

 58.6

19 LTAS 1,761,581 

 ACRES MAPPED 

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 496
SECTION M333B

FLATHEAD VALLEY

 Acres % of % of

LTA Mapped Mapped Section

10 191,532 3.5 3.5

11 533,326 9.8 9.8

12 428,208 7.8 7.8

14 33,343 0.6 0.6

20 212,411 3.9 3.9

40 221,169 4.0 4.0

47 27,452 0.5 0.5

50 2,681,456 49.1 49.1

51 90,791 1.7 1.7

53 8,091 0.1 0.1

58 164,491 3.0 3.0

60 497,972 9.1 9.1

64 19,044 0.3 0.3

68 8,043 0.1 0.1

70 153,508 2.8 2.8

72 967 0.0 0.0

90 1,358 0.0 0.0

99 192,821 3.5 3.5

_____________________________________________________

 100

17 LTAS 5,463,336 

 ACRES MAPPED

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 497
SECTION M333C

NORTHERN ROCKIES

 Acres % of % of

LTA Mapped Mapped Section

10 63,720 1.9 1.9

11 11,821 0.4 0.4

12 97,651 2.9 2.9

14 5,120 0.2 0.2

20 163,793 4.9 4.9

25 10,321 0.3 0.3

27 461 0.0 0.0

40 1,637,034 48.9 48.9

43 235 0.0 0.0

44 218,230 6.5 6.5

50 687,672 20.6 20.6

53 100,613 3.0 3.0

58 20,031 0.6 0.6

60 114,155 3.4 3.4

66 164 0.0 0.0

68 36,067 1.1 1.1

70 60,686 1.8 1.8

74 9,208 0.3 0.3

90 58,472 1.7 1.7

99 49,133 1.5 1.5

_____________________________________________________

 100 .%

19 LTAS 3,344,596

 ACRES MAPPED

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 498
SECTION M333D

BITTERROOT MOUNTAINS

 Acres % of % of

LTA Mapped Mapped Section

10 160,282 2.4 2.3

11 111,455 1.6 1.6

12 181,889 2.7 2.6

14 41,867 0.6 0.6

17 99,346 1.5 1.4

20 1,000,850 14.7 14.5

21 73,456 1.1 1.1

22 9,036 0.1 0.1

23 226,415 3.3 3.3

24 14,019 0.2 0.2

26 4,712 0.1 0.1

28 316,745 4.7 4.6

40 222,209 3.3 3.2

41 24,915 0.4 0.4

45 3,610 0.1 0.1

46 7,904 0.1 0.1

47 49,434 0.7 0.7

50 66,747 1.0 1.0

51 3,788 0.1 0.1

53 42 0.0 0.0

57 9,130 0.1 0.1

60 1,726,317 25.4 25.1

61 122,584 1.8 1.8

62 49,409 0.7 0.7

63 311,815 4.6 4.5

64 123,010 1.8 1.8

66 594 0.0 0.0

67 7,073 0.1 0.1

68 1,511 0.0 0.0

70 518,308 7.6 7.5

71 181,557 2.7 2.6

72 17,671 0.3 0.3

80 122,360 1.8 1.8

81 270,383 4.0 3.9

82 43,729 0.6 0.6

83 292,046 4.3 4.2

84 294,317 4.3 4.3

85 19,796 0.3 0.3

90 16,505 0.2 0.2

99 43,676 0.6 0.6 _____________________________________________________

 98.8

40 LTAS 6,790,567

 ACRES MAPPED 

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 499
SECTION 342A

BIGHORN BASIN

 Acres % of % of

LTA Mapped Mapped Section

27 1,069 29.8 0.0

66 2,524 70.2 0.1

________________________________________________________

 0.14

2 units 3594 

 ACRES MAPPED

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 500
SECTION 251A

RED RIVER VALLEY

 LTA Acres % of % of

 Mapped Mapped Section

8 44,171 33.7 0.1

9 73,167 55.9 0.5

13 13,659 10.4 0.8

____________________________________________________________

 1.4

3 LTAS 130,998

 ACRES MAPPED

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 501
SECTION 251B

NORTH CENTRAL GLACIATED PLAINS

 Acres % of % of

LTA Mapped Mapped Section

8 3,239 55.0 0.1

9 2,655 45.0 0.1

________________________________________________________

 0.2

2 units 5,894 

 ACRES MAPPED

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 502
Appendix G

 LANDTYPE ASSOCIATION LEGEND

 ARRANGED BY GEOLOGIC MATERIAL AND LANDFORM

Earlier in this document the legend that was used for the mapping is given. 

It was organized with landform as the first separation and geologic material

as the second. For the convenience of the reader a second version is provided

here that has geologic material as the first break and landform as the second.

This format is similar to the legend displayed on the 1:100,000 scale maps.

 Alluvium

 10 Valleys, Coarse Deposits

 14 Valleys, Fine Deposits

 Glacial Sediments

 8 Glaciolacustrine Plains: Deltaic Sediments

 11 Valleys: Lacustrine Sediments

 12 Valleys: Coarse Sediments

 13 Valleys: Fine Sediments

 Sandy Wind Deposited Sediments

 9 Hills and Dunes

 Loess

 17 Hills and Plateaus

 Metasedimentary (Belt)

 20 Breaks

 28 Dissected Breaks

 40 Steep Glaciated Mountain Slopes

 47 Alpine Troughs and Trough Walls

 50 Glaciated Mountain Slopes

 60 Mountain Slopes and Ridges

 70 Frost Shattered Mountain Ridge Tops

 80 Low Relief Hills

 Carbonates

 27 Breaks

 37 High Relief Mountain Slopes

 43 Steep Glaciated Mountain Slopes

 66 Mountain Slopes and Ridges

 Granitics

 21 Breaks, Highly Weathered

 22 Breaks, Weakly Weathered

 41 Steep Glaciated Mountain Slopes

 45 Weakly Glaciated Mountain Slopes and Ridges

 46 Alpine Troughs and Trough Walls

 51 Glaciated Mountain Slopes

 61 Mountain Slopes and Ridges, Highly Weathered

 62 Mountain Slopes and Ridges, Weakly Weathered

 71 Frost Shattered Mountain Ridge Tops, Highly Weathered

 72 Frost Shattered Mountain Ridge Tops, Weakly Weathered

 81 Low Relief Hills

 Volcanics

 24 Breaks

 34 High Relief Mountain Slopes

 42 Steep Glaciated Mountain Slopes

 54 Glaciated Mountain Slopes

 64 Mountain Slopes and Ridges

 73 Frost Shattered Mountain Ridge Tops

 82 Low Relief Hills

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 503
 Sandstones and Shales

 25 Breaks

 36 High Relief Mountain Slopes

 44 Steep Glaciated Mountain Slopes

 53 Glaciated Mountain Slopes

 68 Mountain Slopes and Ridges

 74 Frost Shattered Mountain Ridge Tops

 Soft Sedimentary Rocks

 65 Mountain Slopes and Ridges

 Shales, Siltstones and Sandstones

 1 Plains

 2 Glaciated Plains

 3 Dissected Plains

 4 Glaciated Dissected Plains

 5 Badlands

 6 Eroded Uplands

 7 Erosional Plateaus and Buttes

 Quartzites and Calc-silicates

 29 Breaks

 35 Weakly Glaciated Mountain Slopes and Ridges

 67 Mountain Slopes and Ridges

 75 Frost Shattered Mountain Ridge Tops

 Gneisses and Schists

 23 Breaks

 26 Breaks, Moderately Weathered

 39 Steep Glaciated Mountain Slopes

 57 Glaciated Mountain Slopes

 59 Mountain Slopes and Ridges, Moderately Weathered

 63 Mountain Slopes and Ridges

 77 Frost Shattered Mountain Ridge Tops

 84 Low Relief Hills, Highly Weathered

 85 Low Relief Hills, Moderately Weathered

 Tertiary Sediments

 83 Low Relief Hills, Coarse Sediments

 88 Low Relief Hills, Fine Sediments

 Undifferentiated (Mixed Geology)

 69 Pediment

 90 Mass Wasted Slopes

 92 Colluvial Slopes

 Miscellaneous

 99 Lakes and Reservoirs

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 504
Appendix H

 LIST OF COMMON AND SCIENTIFIC NAMES FOR

 POTENTIAL NATURAL VEGETATION SERIES USED IN THIS REPORT

Alkali grass Puccinellia nuttalliana

Aspen Populus tremuloides

Baltic rush Juncus balticus

Basswood Tilia americana

Big bluestem Andropogon gerardii

Bluebunch wheatgrass Agropyron spicatum

Big sagebrush Artemisia tridentata wyomingensis

Buffaloberry Shepherdia argentea

Burr oak Quercus macrocarpa

Curlleaf mountain mahogany Cercocarpus ledifolius

Douglas-fir Pseudotsuga mensiesii

Engelmann spruce Picea engelmannii

Geyer willow Salix geyeriana

Grand fir Abies grandis

Greasewood Sarcobatus vermiculatus

Green ash Fraxinus pennsylvanica

Hairy grama Bouteloua hirsuta

Holm's Rocky Mountain Sedge Carex scopulorum

Horizontal juniper Juniporus horizontallis

Idaho fescue Fextuca idahoensis

inland saltgrass Distichlis spicata.

Little bluestem Andropogon scoparius

Limber pine Pinus flexilis

Low sagebrush Artemisia arbuscula

Mountain big sage Artemisia tridentata vaseyana

Mountain hemlock Tsuga mertensiana

Needle and thread Stipa comata

Parry's rush Juncus parryi

Plains cottonwood Populus deltoides

Ponderosa pine Pinus ponderosa

Prairie cordgrass Spartina pectinata

Prairie sandreed Calmovilfa longifolia 

Rocky Mountain juniper Juniporus scopulorum 

Rough fescue Festuca scabrella

Sand bluestem Andropogon hallii 

Shadscale Atriplex confertifolia 

Shrubby cinquefoil Potentilla fruiticosa

Silver sagebrush Artemisia cana

Skunkbrush Rhus aromatica 

Slender wheatgrass Agropyron caninum

Subalpine fir Abies lasiocarpa

Tufted hairgrass Deschampsia caespitosa

Water sedge Carex aquatilis

Western hemlock Tsuga heterophylla

Western redcedar Thuja plicata

Western snowberry Symphoricarpus occidentalis

Western wheatgrass Agropyron smithii

White dryad Dryas octopetala

Whitebark pine Pinus albicaulis

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 505
Appendix I

GLOSSARY

The definitions listed below are taken from the following sources : 1) the

Glossary of Landforms in the USDA Natural Resource Conservation Service

National Soils Handbook, 2) the American Geological Institute's Dictionary of

Geological Terms, and 3) the American Fisheries Society's Glossary of Stream

Habitat Terms. Consult the reference section for complete citations.

Alluvial: Pertaining to material or processes associated with transportation

and/or subaerial deposition by concentrated running water.

Alluvium: Unconsolidated clastic material deposited by running water,

including gravel, sand, silt, clay and various mixtures of these.

Antecedent stream: A stream that flowed in its present course prior to the

development of the existing topography; a stream that was established before

local uplift began and incised its channel at the same rate the land was

rising.

Archean: The term, meaning ancient, has been generally applied to the oldest

rocks of the Precambrian.

Badlands: A landscape which is intricately dissected and characterized by a

very fine drainage network with high drainage densities and short, steep

slopes with narrow interfluves. Badlands develop on surfaces with little or no

vegetative cover, overlying unconsolidated or poorly cemented materials

(clays, silts, or in some cases sandstones) sometimes with soluble minerals

such as gypsum or halite.

Batholith: A body of intrusive rock at least 40 square miles in area.

Cenezoic: The latest of the four eras into which geologic time, as recorded by

the stratified rocks of the earth's crust, is divided; it extends from the

close of the Mesozoic Era to and including the present.

Cirque: Semicircular, concave, bowl -like area with steep face primarily

resulting from erosive activity of a mountain glaciers.

Colluvial: Pertaining to material or processes associated with transportation

and/or deposition by mass movement (direct gravitational action) and local,

unconcentrated runoff on sideslopes and/or at the base of slopes.

Colluvium: Unconsolidated, unsorted earth material being transported or

deposited on sideslopes and/or at the base of slopes by mass movement (e.g.

direct gravitational action) and by local, unconcentrated runoff.

Crystalline: Of, or pertaining to the nature of a crystal, having regular

molecular structure. Contrasted with amorphous (without form)

Ephemeral stream: A stream, or reach of a stream, that flows only in direct

response to precipitation. It receives no protracted supply from melting snow

or other source, and its channel is, at all times, above the water table.

Felsic: a light colored rock containing feldspar and silica.

Fluvial: Of or pertaining to rivers; produced by river action.

Frost shattering: The mechanical disintegration or breakup of a rock or soil

caused by the pressure exerted by freezing water in cracks or pores, or along

bedding planes.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 506
Geomorphic: Of, or pertaining to, the figure of the earth or the form of its

surface.

Glaciofluvial deposits: Material moved by glaciers and subsequently sorted

and deposited by streams flowing from the melting ice. The deposits are

stratified and may occur in the form of outwash plains, valley trains, deltas,

kames, eskers, and kame terraces.

Glaciolacustrine deposits: Material ranging from fine clay to sand derived

from glaciers and deposited in glacial lakes by water originating mainly from

the melting of glacial ice. Many are bedded or laminated with varves or

rhythmites.

Hogback: A sharp anticlinal, ridge, decreasing in height at both ends until it

runs out; a ridge produced by highly tilted strata.

Horn: A high pyramidal peak with steep sides formed by the intersecting walls

of three or more cirques, as, the Matterhorn.

Jokulhlaup: An Icelandic term for a glacial outburst flood, especially when

an ice dam impounding a glacial lake breaks. Such breaks drained glacial Lake

Missoula and created the Channeled Scablands in the Pacific Northwest.

Lag gravel: Residual accumulations of coarse particles from which the finer

material has been blown away.

Landform: One of the multitudinous features that taken together make up the

surface of the earth. It includes all broad features, such as plain, plateau,

and mountain, and also all the minor features, such as hill, valley, slope,

canyon, and alluvial fan.

Loess: Fine-grained, wind-deposited material, dominantly of silt size.

Mafic minerals: In general, synonymous with "dark minerals: as usually used;

basic; pertaining to or composed dominantly of the magnesian rock forming

silicates.

Mazama volcanic ash: Ash that originated at the present site of Crater Lake

in Oregon. Crater Lake is the remnant of a volcanic peak named Mount Mazama

which once occupied the site and was the source of much of the volcanic ash

deposited in the Pacific Northwest.

Metasedimentary rocks: Sedimentary rocks which show evidence of having been

subjected to metamorphism.

Outwash: Stratified detritus (chiefly sand and gravel) removed or "washed

out" from a glacier by melt-water streams and deposited in front of or beyond

the end moraine or the margin of an active glacier. The coarser material is

deposited nearer to the ice.

Pediment: A gently sloping erosional surface developed at the foot of a

receding hill or mountain slope. The surface may be essentially bare, exposing

earth material that extends beneath adjacent uplands; or it may be thinly

mantled with alluvium and colluvium, ultimately in transit from upland front

to basin or valley lowland.

Periglacial: Refers to areas, conditions, processes, and deposits adjacent to

the margin of a glacier.

Potential vegetation: The biotic community that would be established if all

successional sequences of its ecosystem were completed without additional

human-caused disturbance under present environmental conditions.

Proterozoic: In common use the younger of the two Precambrian eras.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 507
Residuum: Unconsolidated, weathered, or partly weathered mineral material that

accumulates by disintegration of bedrock in place.

Riparian: Pertaining to anything connected with or immediately adjacent to the

banks of a stream or other body.

Scree slope: Any slope covered with loose rock fragments. Same as talus.

Series: A group of habitat types having the same potential climax tree (shrub

or grass) species. 

Talus: A collection of fallen disintegrated material which has formed a slope

at the foot of a steeper declivity. Same as scree.

Till: Dominantly unsorted and unstratified drift, deposited by a glacier, and

consisting of a heterogeneous mixture of clay, silt, sand, gravel, stones, and

boulders.

Tor: A high,isolated pinnacle, or rocky peak, or a pile of rocks, much jointed

and usually granitic, exposed to intense weathering, and often assuming

peculiar or fantastic shapes.

Weathering: All physical disintegration, chemical decomposition, and

biologically induced changes in rocks or other deposits at or near the earth's

surface by atmospheric or biologic agents or circulating surface waters with

essentially no transport of the altered material. These changes result in

disintegration and decomposition of the material.

 

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 508
Appendix J

REFERENCES

American Fisheries Society. 1985. Glossary of stream habitat terms. Bethesda,

MD: American Fisheries Society, Habitat Index Committee, West Division. 34 p.

American Geological Institute. 1976. Dictionary of geological terms, revised

edition. Anchor Press/Doubleday, Garden City, New York

Bailey, R. G.; Avers, P. E.; King, T.; McNab, W. H. eds. 1994a. Ecoregions and

subregions of the United States (map). Washington, D.C.: U.S. Geological

Survey. Scale 1:7,500,000; colored. Accompanied by a supplementary table of

map unit descriptions compiled and edited by McNab, W.H. and Bailey, R.G.

Prepared for the U.S. Department of Agriculture, Forest Service.

Bailey, R.G.; Jensen, M.E.; Cleland, D.T. and Bourgeron, P.S. 1994b. Design

and use of ecological units. In: Jensen, M.E.; Bourgeron, P.S. tech. eds.

1994. Volume II: Ecosystem management: principles and applications. Gen. Tech.

Rep. PNW-GTR_318. Portland, OR: U.S. Department of Agriculture, Forest

Service, Pacific Northwest Research Station. 376p.

Baker, C. H., Jr. 1967. Geology and ground water resources of Richland County,

ND. North Dakota Geological Survey. Fargo, ND. Bulletin 46, 45 p

Beaverhead National Forest. 1991. Classification of alpine habitat types for

mountain ranges of the Beaverhead National Forest. Unpublished report. USDA

Forest Service, Dillon, Montana

Becraft, G. E., and Pinckney, D. M. 1961 Preliminary Geologic Map of the

Northwest Quarter of the Boulder Quadrangle, Montana. Mineral Investigations

Field Studies Map, MF-183. Washington, D.C.: U.S. Department of Interior,

Geological Survey. Scale 1:24,000, 1 sheet.

Becraft, G. E.; Pinckney, D.; Rosenblum, S. 1963. Geology and Mineral

Deposits of the Jefferson City Quadrangle, Jefferson and Lewis and Clark

Counties, Montana. U.S.G.S. Professional Paper 428. Washington, D.C.: U.S.

Government Printing office.

Billingsley, Owen. 1975. Planning Geology for the Upper Willow Creek

Drainage, Philipsburg Ranger District, Deerlodge National Forest. 

Unpublished Report. Butte, Montana : Deerlodge National Forest. Scale 

1:31,680, 9 sheets.

Bluemle, J. P. 1979 Geology of Ransom and Sargent Counties, ND, North Dakota

Geological Survey. Fargo, ND. Bulletin 69, 84p.

Calkings, F. C.; and Emmons, W. H. 1915. Geologic Atlas of the United States,

Philipsburg folio, Montana. Washington, D.C.: U.S. Department of Interior,

Geological Survey.

Caprio, J. M.; Cooksey, D. I.; Jackson, J. S.; Nielsen, G. A.; and Roche, R.

R. 1994. MAPS Atlas: a land and climate information system, version 5.0.

Extension Service. Montana State University, Bozeman, Montana

Carlson, C. G. 1983, Geology of Billings, Golden Valley, and Slope Counties,

North Dakota. North Dakota Geological Survey. Fargo, ND. Bulletin 76, 40 p

Carlson, C. G. 1985. Geology of McKenzie County, ND. North Dakota Geologial

Survey. Fargo, ND. Bulletin 80. 54 p

Carlson, C. G. 1982. Geology of Grant and Sioux Counties, ND. North Dakota

Geological Survey. Fargo, ND. Bulletin 67. 32 p.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 509
Carrara, P. E. 1990. Surficial geologic map of Glacer National Park, Montana.

Map I-1508-D. Department of the Interior. Geological Survey

Clark, Dean S. 1953. Reconnaissance Geology of a Portion of Powell and Deer

Lodge Counties, Montana. Unpublished Master Thesis, Indiana University.

Clayton, J. L. and Arnold, J. F. 1972. Practical grain size fracturing

density, and weathering classification of intrusive rocks of the Idaho

Batholith, Intermountain Forest and Range Experiment Station, General

Technical Report INT-2, Ogden, Utah)

Cole, N. J.; Joy, J. W.; and Koch, H. 1979. Unpublished Habitat Type Maps of

the Deerlodge National Forest. Scale 1:24,000, 96 sheets.

Cooper, S. V; Neiman, K. E. and Roberts, D. W. 1991. Forest habitat types of

northern Idaho: a second approximation. Gen. Tech Rpt. INT-236. USDA Forest

Service, Intermountain Research Station, Ogden, Utah

Davis, C. and Shovic H. F. 1996. Soil survey of the Gallatin National Forest

Montana, USDA Forest Service, Bozeman, Montana

Derkey, P. D. and Bartholomew, M. J. 1988. Geologic Map of the Ramsay

Quadrangle, Montana. Geologic Map 47. Butte, Montana: Bureau of Mines and

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Earll, F. N. 1972. Mines and Mineral deposits of the Southern Flint Creek

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Reinhold.

Girard, M. H.; Geotz, H. and Bjugstad, A. J. 1989. Native woodland habitat

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Green, P. and Kellogg, G. 1987. Soil Survey of Nez Perce National Forest Area.

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Colorado. pp. 68.

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USDA-FS Rocky Mtn Forest and Range Exp Sta. Ft. Collins, Colorado. pp. 33.

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RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 510
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RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 511
Mueggler, W. F. and Stewart, W. L. 1980. Grassland and shrubland habitat types

of western Montana. USDA Forest Service. Gen. Tech. Rpt. INT-66, Intermountain

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habitat types of Montana. Intermountain Forest and Range Exp. Stn. Gen. Tech

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Geological Survey. Scale 1:24,000, 1 sheet.

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Montana

Poulter, G. J. 1956. Geology of the Georgetown Thrust Area Southwest of

Philipsburg, Montana. Geological Investigations Map No. 1. Butte, Montana:

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Mountains, Madison County, Montana. Memoir 36. Butte, Montana: Bureau of

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RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 514
Abbreviations Used on Summary Bar Charts

Geologic Materials:

 AL Alluvium,

 DS Deltaic Sediments

 GNST Gneiss,Schist

 GR Granitics

 LC Lacustrine Deposits

 LO Loess

 MIX Mixed Geology

 MS Metasediments

 QUCS Quartzite,Calc-Silicate

 SC, Carbonates

 SHSS Shale,Siltstone,Sandstone

 SSED Soft Sedimentary

 SSSH Sandstone,Shale

 TSED Tertiary Sediments

 VOL Volcanics

 WSD Wind Deposited Sediments

Landforms:

 BA Badlands

 BK Breaks

 BKMW Breaks

 CODP Colluvial Deposits

 DIBK Breaks

 DIPL Dissected Plains

 ERUP Eroded Uplands

 MORI Frost-Shattered Mountain Ridges

 GLDIPL Dissected Glaciated Plains

 GLLAPL Glaciated Lacustrine Plains

 GLMS Glaciated Mountain Slopes

 GLMSRI Glaciated Mountain Slopes and Ridges

 GLPL Glaciated Plains

 HIDU Hills and Dunes

 HIPT Hills and Plateaus

 HRMS High Relief Mountain Slopes

 

 

 LOHILL Low Relief Hills

 MSRI Mountain Slopes and Ridges

 MSRIMW Mountain Slopes and Ridges,Moderately Weathered

 MWSL Mass Wasted Slopes

 PED Pediment

 PL Plains

 PTBT Erosional Plateaus and Buttes

 STGLMS Steep Glaciated Mountain Slopes

 TR Glacial Troughs and Trough Walls

 VA Valleys

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 515
Introducing SOLO: 

 Interactive decision support software for SOil quality monitoring and LOng term ecosystem

sustainability.

WHAT IS SOLO?

 SOLO is a computerized collection of representative documentation on soil monitoring and long term

ecosystem sustainability, linked together electronically by topic, author, key word or phrase and similar

geography. The information may be surveyed by activating ‘push-buttons’ on the computer screen.

RMRS-GTR-2-CD: Landtype associations of the Northern Region 1997: A first approximation 516
Natural Resource

Information System

MONTANA

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MONTANA

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Information System

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Information System

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Figure 93
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Figure 94