United States

Department of

Agriculture

Forest

Service

July 2017

Silviculture Report

Craggy Vegetation Management

Klamath National Forest

Siskiyou County, California

For Information Contact: Carl Varak or Marissa Jones

11263 N. Hwy 3 Fort Jones, CA

530.468.1227 or 530.468.1276

Non-Discrimination Policy

The U.S. Department of Agriculture (USDA) prohibits discrimination against its customers, 

employees, and applicants for employment on the bases of race, color, national origin, age, disability, 

sex, gender identity, religion, reprisal, and where applicable, political beliefs, marital status, familial or 

parental status, sexual orientation, or all or part of an individual's income is derived from any public 

assistance program, or protected genetic information in employment or in any program or activity 

conducted or funded by the Department. (Not all prohibited bases will apply to all programs and/or 

employment activities.)

To File an Employment Complaint

If you wish to file an employment complaint, you must contact your agency's EEO Counselor (PDF) 

within 45 days of the date of the alleged discriminatory act, event, or in the case of a personnel 

action. Additional information can be found online at www.ascr.usda.gov/complaint_filing_file.html.

To File a Program Complaint

If you wish to file a Civil Rights program complaint of discrimination, complete the USDA Program 

Discrimination Complaint Form (PDF), found online at www.ascr.usda.gov/ complaint_filing_cust.html, 

or at any USDA office, or call (866) 632-9992 to request the form. You may also write a letter 

containing all of the information requested in the form. Send your completed complaint form or letter 

to us by mail at U.S. Department of Agriculture, Director, Office of Adjudication, 1400 Independence 

Avenue, S.W., Washington, D.C. 20250-9410, by fax (202) 690-7442 or email at 

program.intake@usda.gov.

Persons with Disabilities

Individuals who are deaf, hard of hearing or have speech disabilities and you wish to file either an 

EEO or program complaint please contact USDA through the Federal Relay Service at (800) 877-

8339 or (800) 845-6136 (in Spanish).

Persons with disabilities who wish to file a program complaint, please see information above on how 

to contact us by mail directly or by email. If you require alternative means of communication for 

program information (e.g., Braille, large print, audiotape, etc.) please contact USDA's TARGET 

Center at (202) 720-2600 (voice and TDD).

Silviculture Report Craggy Vegetation Management Project

i

Table of Contents

Silviculture Report.......................................................................................................................1

Introduction............................................................................................................................. 1

Methodology........................................................................................................................... 1

Analysis Indicators.................................................................................................................. 2

Measures............................................................................................................................. 2

Spatial and Temporal Bounding of Analysis Area ................................................................. 4

Affected Environment............................................................................................................. 5

Current and Desired Stand Conditions: .............................................................................. 9

Natural Conifer Stands:................................................................................................... 9

Plantations:.................................................................................................................... 10

Environmental Consequences............................................................................................... 11

Alternative 1...................................................................................................................... 11

Direct and Indirect Effects............................................................................................ 11

Cumulative Effects........................................................................................................ 12

Alternative 2...................................................................................................................... 12

Direct and Indirect Effects............................................................................................ 12

Cumulative Effects........................................................................................................ 13

Alternative 3...................................................................................................................... 13

Direct and Indirect Effects............................................................................................ 13

Cumulative Effects........................................................................................................ 14

Comparison of Alternatives.................................................................................................. 14

Compliance with law, regulation, policy, and the Forest Plan ............................................. 15

Literature Cited..........................................................................................................................16

List of Tables

Table 1: Detailed Explanation of SDI Classes..............................................................................................3

Table 2: Range of Stand Density Index Values by Density and Species......................................................4

Table 3: Percent of Landscape by Society for Range Management Cover Type .........................................5

Table 4: Percent of Landscape within each Diameter Class for Forested Cover Type.................................6

Table 5: Alternative 1 Effects on Forest Health. ........................................................................................11

Table 6: Alternative 2 Effects on Forest Health. ........................................................................................13

Table 7: Alternative 3 Effects on Forest Health. ........................................................................................14

Table 8: Comparison of Effects on Forest Health.......................................................................................15

List of Figures

Figure 1: Previously Masticated and Thinned Plantation within Craggy Project Area ................................1

Figure 2: Pocket of Beetle Activity in Little Humbug Drainage, 2016 ........................................................8

Figure 3: Area Representative of Natural, Conifer Stands within Project Area ...........................................9

Figure 4: Western Pine Beetle Activity on Craggy Mountain within Project Area....................................10
Silviculture Report Craggy Vegetation Management Project

ii

Figure 5: Desired Future Condition with Mix of Larger Diameter Trees, Natural Regeneration in 

Openings, and Open Canopy Structure for Growing Space and Fire Resilience................................11
Silviculture Report Craggy Vegetation Management Project

1

Silviculture Report

Introduction

This report provides information on the existing condition of silviculture in the Craggy 

project area and the effects of various alternatives on this resource. General information 

on the location of the project and the guidance for the project are provided in chapter 1 of 

the environmental impact statement. This analysis will address the issues and 

opportunities surrounding the promotion of more vigorous, insect, disease, and fire

resistant stands in the project area.

Methodology

Field data were collected from a representative sample of forested stands in the project 

area during the summer and fall of 2012. A field crew of four people collected vegetation 

and fuels data within designated stands to be used in the Forest Vegetation Simulator

(FVS) to model existing and projected stand structures. Plots were randomly located in 

ArcMap (a geospatial mapping program) and visited to collect woody vegetation 

inventory data using a variable radius plot design. Variable radius plot design helps to 

determine basal area easily since each measured 

tree in a plot represents a given amount of basal 

area, as determined by the basal area factor. We 

established variable radius plots using a basal area 

factor of 20, so each tree would represent 20 square 

feet of basal area. These data were analyzed in the 

FVS to estimate current stand attributes including 

the site class, canopy cover, basal area, trees per 

acre, and stand density. Tree diameters are 

measured at a height of 4.5 feet above the forest 

floor on the uphill side of the tree. In addition to the 

data collection process, on-site field reviews were 

conducted by a certified silviculturist in multiple 

stands across the landscape. Using the vegetation 

data collected and field observations, the 

silviculturist formulated stand diagnoses and 

preliminary silvicultural prescriptions were 

developed.

Figure 1: Previously Masticated and Thinned Plantation within Craggy Project Area

Prescribed treatments for thinning stands with and without forest product removal, were 

then assessed with FVS to simulate the effect of the treatments on stand development and 

fire resistance (Keyes 2002).

Stand dynamics were also modeled using FVS. The Inland California Southern Cascades 

model variant of FVS was used to create region-specific modeling results over a 30-year 

period. The modeled results from FVS are not intended to be absolute values; rather they 

display relative trends in stand development for each of the defined categories. Models 
Silviculture Report Craggy Vegetation Management Project

2

are run for the average treatment across the stand category. While the models are 

developed from actual stand category data and would reflect variation within the 

category, they do not necessarily display the within-stand variability. For example, 

culturing of large trees will require wider spacing around selected trees (35 feet and 

more) compared with the more common closer spacing (25 to 30 feet). The model only 

addresses the average thinning accomplished in the stand. Another modeling limitation is 

that FVS does not consider un-thinned areas within a stand. Trees in these un-thinned

areas could have slower growth and higher mortality which could have an effect on 

vegetation surrounding the un-thinned patch in the form of reduced growth and increased 

risk of insect outbreaks. These areas may go un-thinned because of resource-specific 

concerns such as heritage site protection, riparian buffers, or risk of soil damage from 

logging due to limitations in logging system technology.

Modeling results from FVS analysis include future tree growth, stand structure and stand 

density. These measures relate most directly to the purpose and need of the project and 

are readily comparable to the stand management objectives. These measures were used in 

the forest vegetation simulator to assist in developing prescriptions designed to take the 

stands from their current state to one where desired stand health objectives and habitat 

characteristics are met and stands become more resilient to fire.

Prescribed treatments for mastication, fuel breaks and underburning units were not 

modeled using FVS. Fuel break treatments and mastication may act similarly to thinning 

without forest product removal units as stand densities and vegetation densities will be 

reduced and competition-induced mortality lessened. Underburning can be expected to 

have variable results depending on fuel loading distribution and tree size. Some mortality 

of smaller diameter trees can be expected, though exact numbers are not known. 

Surviving trees are likely to have some degree of reduced competition and an increase in 

resources available for their growth. Underburned stands are likely to have increased 

resilience to future wildland fire as fuel loading will be reduced. See the fire and fuels 

report for more information on conditions of stands to be underburned.

Analysis Indicators

• Forest health

• Forest resilience

Measures

Forest health is the ability of trees to utilize available water and nutrient resources to 

grow, increase vigor, and maintain the ability to respond to disturbance mechanisms 

(avoiding early mortality). It is measured by the stand density index (SDI). Stand 

density index is a measure of tree stocking that uses tree size (diameter) and numbers 

(trees-per-acre) to derive a measure of how site resources in stands are being utilized and 

the level of competition in stands for site resources. This measure is better for 

determining density than trees per acre or basal area alone.

Stand density affects stand health and the ability of trees to respond to disturbance 

mechanisms. High stand density, such as what is found in the project area, leads to 

competition for limited resources needed for growth and survival. Competition in turn, 
Silviculture Report Craggy Vegetation Management Project

3

leads to reduced growth and vigor, increased susceptibility to insects and disease, and to 

eventual mortality. Weakened trees are more likely to succumb to the effects of 

disturbance mechanisms such as disease, insects, and fire. An SDI of 230 defines the 

lower threshold for a zone of imminent bark beetle mortality within which endemic 

populations kill a few trees but net growth is still positive (Oliver 1995). Values over this 

threshold are indicative of an overly dense stand subject to beetle induced mortality and 

subsequent risk of high severity wildfire.

Reineke (1933) first introduced SDI as a measure of site occupancy. He found that SDI 

could be consistently applied to calculate a maximum density expected for a given 

average stand diameter. SDI has an advantage over basal area because it is not 

significantly affected by age and site quality. Maximum SDI values have been developed 

for a variety of species including white fir, Douglas-fir and ponderosa pine. The 

maximum SDI value for each species is 759, 600, and 436 respectively. Table 1 describes 

the interactions associated with maximum stand densities.

In order to minimize self-thinning and associated fuels build-up, and to promote growth, 

stands should be below 55 percent of maximum SDI (Reineke 1933). A zone of imminent 

mortality, or where self-thinning begins to occur, is reached at 55 percent of maximum 

SDI (Reineke 1933). This would equate to SDI values of 418 for white fir, 330 for 

Douglas-fir and 241 for ponderosa pine. Different tree species will be able to grow and 

prosper at different stand densities as previously listed. For example, in a mixed conifer 

stand with an SDI of 500, one could expect to find that most of the ponderosa pine have 

died, the Douglas-fir struggling to maintain itself and the white fir still growing but at a 

slow rate. Oliver’s SDI value of 230 is within the range of a high stand density index 

class for the ponderosa and Jeffrey pine species and is used as the target SDI to preclude 

bark beetle mortality. Stand density, however, will vary according to site conditions, 

which is why a range has been calculated for each species. Ranges for each species by 

stand density index class are listed in Table 2. For ponderosa pine and Jeffrey pine 

species, the high density range is 149 to 240 for full occupancy.

Table 1: Detailed Explanation of SDI Classes

% Maximum 

SDI

Competitive Interactions

0-24% Low 

Density

Less than full site occupancy, maximum understory forage production. 

No competition between trees, little crown differentiation. Maximum 

individual tree diameter growth. Minimum whole stand volume growth.

25-34% Moderate 

Density

Less than full site occupancy, intermediate forage production. Onset of 

competition among tree, onset of crown differentiation. Intermediate 

individual tree diameter growth. Intermediate whole stand volume 

growth.

35-55% High 

Density

Full site occupancy, minimum forage production. All site resources are 

being utilized and there is active competition among trees for site 

resources, active crown differentiation. Declining individual tree 

diameter growth. Maximum whole stand volume growth. Upper range of 

zone marks the threshold for the onset of density-related mortality.
Silviculture Report Craggy Vegetation Management Project

4

% Maximum 

SDI

Competitive Interactions

56+% Extremely 

High Density

Full site occupancy, minimum to no forage production. Severe 

competition among trees, active competition-induced mortality. 

Minimum individual tree diameter and growth, stagnation. Declining 

whole stand volume growth due to mortality (some trees have to die for 

other trees to continue to grow).

SDI max basis: ponderosa pine/Jeffrey pine (PP/JP) (436), Douglas-fir (DF) (600), white 

fir (WF) (759), incense cedar (IC) (570), red fir (RF) (800), mixed conifer (MC) (436), 

sugar pine (SP) (436)

Table 2: Range of Stand Density Index Values by Density and Species

SDI Class SDI Range by Species

PP/JP/SP/MC DF WF IC RF

Low Density (0-24% of SDI max) 0-104 0-144 0-182 0-136 0-192

Moderate Density (25-34% of SDI max) 105-148 145-204 183-258 137-194 193-272

High Density (35-55% of SDI max) 149-240 205-330 259-417 195-314 273-440

Extremely High Density (56+% of SDI

max)

241 + 331 + 418 + 315 + 441 +

Forest resilience is measured by heterogeneity of tree species and composition. It is the 

ability of a stand to successfully resist disturbances. With uncertainty as to when effects 

of climate change will become apparent or when insect outbreaks will occur, 

heterogeneity of tree species and composition, or species diversity, increases the 

likelihood of maintaining sustainable, forested conditions in the event of a number of 

disturbances such as insect outbreaks or wildfire. For this project, heterogeneity is

measured by the modeled number of acres on the landscape that are comprised of 

multiple species without specifying particular species. Heterogeneity of particular species 

will be evaluated qualitatively by comparing modeled outcomes of species diversity with 

the unit-specific written prescriptions.

Spatial and Temporal Bounding of Analysis Area

Spatial bounding is limited to the project area. Silvicultural prescriptions and subsequent 

analysis are applied specifically to the stands within the project area designated as 

treatment units; however, due to the homogeneity of the landscape, effects can be 

generalized to the broader area.

Temporal bounding for effects extends out to 20 years following inventory conditions. 

Short term analysis will be one year after treatment to assess change in stand conditions 

immediately following implementation. Stand development was modeled for a 20 year 

period and treatment effects are projected 20 years after the treatment year. That is 

adequate time in which to display the long-term differences on stand development 

between treating and not treating stands in the project area. This temporal bound also 

meets regional forester direction to incorporate treatments that are effective for at least 20 

years (USDA 2004).
Silviculture Report Craggy Vegetation Management Project

5

Affected Environment

Background: The majority of the project area, except for the easternmost 25 percent, is 

within the footprint of the 1955 Haystack Fire. The high intensity, stand-replacing event 

began in September and burned more than 60,000 acres of timber, brush and hardwoods. 

The majority of the fire area experienced significant road construction and salvage 

logging in 1956 and 1957. While it appears there was some high lead cable yarding, the 

vast majority of the salvaged timber was logged with tracked skidding equipment 

(bulldozers). Most areas were clear cut or heavily partial cut as evidenced by the 1964 

aerial photography and district reforestation records. Records indicate that many of the 

salvaged stands had some form of residual fuels treatment (most likely dozer piling or 

broadcast burning) prior to reforestation. Both broadcast seeding, with endrin-treated 

seed (coating treatment to protect field-sown seed from rodents) and planting bare root 

conifer seedlings occurred after the site preparation work. Overall, artificial conifer 

regeneration was attempted on more than 6,100 acres. Due to the lower site productivity 

of many south- and west- facing slopes, the more geographically widespread seed zone 

delineation at the time (Zone X, from the Oregon border to Lake County on the 

Mendocino National Forest) and a well-established brush and hardwood component in 

many areas, the overall reforestation effort was not completely successful. Inter-planting 

and replanting helped restock some of the areas that initially did not meet desired 

stocking levels. There are also stands where residual conifers provided natural seeding 

and establishment of more fully stocked conifer stands.

In the late 1960s through the mid-1970s some stands that were moderately steep, 45 to 60

percent slopes, with poor to no conifer stocking were terraced. This consisted of 

constructing a relatively flat, on the contour, 8- to 10-foot wide trail with a bulldozer. 

These terraces were subsequently planted to conifers that were more genetically adapted 

to the site. This treatment occurred on approximately 1,000 acres in the project area. 

Another significant attempt to restock areas void of conifers took place from the late 

1980s into the early twenty first century. Brush laden stands on less than 45 percent

slopes were piled by a bulldozer with a brush rake and then tilled with a three-tined 

winged subsoiler and planted to conifers. This stocking effort re-established conifers on 

another 900 acres. The result of all these conifer restoration projects is that the majority 

of the project area is a relatively young, pole- to small-sized conifer-dominated 

landscape.

The Craggy project area was characterized using a rangeland cover type developed by the 

Society for Range Management (Shiftlet 1994). Cover type data was most recently 

updated in 2007. Cover type and diameter class are combined with district records of past 

management activities to provide a picture of the existing condition of the project area. 

Table 3 represents the breakdown by cover type and percent of landscape.

Table 3: Percent of Landscape by Society for Range Management Cover Type

Society for Range 

Management Cover Type Percent of landscape

Forested 62%

Shrubland/Hardwoods 36%
Silviculture Report Craggy Vegetation Management Project

6

Society for Range 

Management Cover Type Percent of landscape

Grasslands and meadows ≈1%

Barren land/ Urban ≈1%

Within the forested landscape, tree diameter classes also help characterize the age or 

growth of the vegetation. Seedlings and saplings (0.1 to 4.9 inches quadratic mean 

diameter), pole-size timber (5 to 9.9 inches quadratic mean diameter), small timber (10 to 

19.9 inches quadratic mean diameter), medium-sized timber (20 to 29.9 inches quadratic 

mean diameter), and large timber (30 inches or greater quadratic mean diameter) are 

present in varying quantities across the landscape. Table 4 displays the percent of the 

landscape occupied by these designations in addition to a small portion of non-stocked 

forest lands. As displayed, large trees occupy only a very small percentage of the forested 

landscape.

Table 4: Percent of Landscape within each Diameter Class for Forested Cover Type

Tree Diameter Class Percent of landscape

Seedlings/Saplings 7%

Pole-size 37%

Small timber 31%

Medium timber 23%

Large timber 0.4%

Non-stocked 2%

Stocking control to varying intensities has taken place over the past 40 years on 2,900 

acres. This included manual thinning of conifers to an average spacing of 14 to 18 feet 

without forest product removal and mastication to reduce brush and density of planted 

trees. The plantation trees now range in size from three inches in diameter and 15 feet in 

height (those most recently planted) to more than 18 inches in diameter and over 80 feet 

tall (planted in the late 1950s). Most stands consist of well-formed trees with good 

growth characteristics. There are, however, numerous stands with trees that are multitopped and have deformed boles. This indicates genetically non-adapted trees due to the 

extremely large geographic base of Zone X stock or poor parent tree selections during 

cone collection. Some of the smaller trees are simply a result of poorer quality sites of 

which there are an abundance throughout the project area. On the terraces, the effect of 

removing all the organic material and much of the A-horizon of the soil profile (the layer 

where most root activity occurs and typically the most productive mineral layer) has 

slowed the growth of some of the trees.

The natural stands are found to be in two categories, those that were partially destroyed in 

the Haystack fire and those that didn’t burn. Those that experienced the 1955 fire have a 

more vigorous and well-developed understory of sapling to pole-sized stems with 

hundreds of stems per acre. The unburned stands have an understory that is generally less 

dense and not as contiguous. The “non-fire” stands also have less thrifty understories and 

their over-stories are experiencing significant drought-induced mortality as evidenced 

during the mid-1990s and again in the past three to four years due to consecutive years of 

below average precipitation. While trees of all sizes have died, generally it has been the 

larger diameter trees that have succumbed.
Silviculture Report Craggy Vegetation Management Project

7

The availability of water and nutrients affect overall stand vigor and growth. The project 

consists of productive soils (Forest Survey Site Class 2 through 5). Annual precipitation 

is 35 to 55 inches, with about 90 percent falling between October and May. At the higher 

elevations, the precipitation is predominantly snowfall. The availability of moisture is the 

most limiting factor for conifer survival and growth.

Stand density influences the amount of water and nutrients available to individual trees. 

High conifer stocking levels lead to competition for limited resources needed for growth 

and survival. Competition, in turn, leads to reduced growth and vigor, increased 

susceptibility to insects and disease, and eventually mortality. Stand density affects stand 

health and the ability of trees to respond to disturbance mechanisms. High tree densities 

lead to increased competition for the limited resources needed to remain alive and 

growing. Weakened trees are more likely to succumb to the effects of natural disturbance 

mechanisms such as disease, insects and fire.

Most of the stands in the project area are moderately to heavily-stocked. Current stand 

densities are not sustainable over time as witnessed by ongoing mortality which is 

especially noticeable in the pine plantations and on the drier south and west slopes. The 

limiting SDI for ponderosa pine stands in Northern California as defined by 

Dendroctonus bark beetles is 365. An SDI of 230 defines the lower threshold for a zone 

of imminent bark beetle mortality within which endemic populations kill a few trees but 

net growth is still positive (Oliver 1995). This threshold is similar to the threshold 

discussed earlier where density-induced mortality occurs. The primary difference is that 

instead of suppressed conditions being the driver of mortality, beetles are the driving 

force for killing trees. Many of the plantations within the Humbug watershed are planted 

to ponderosa and Jeffrey pine which are susceptible to the western pine beetle and Jeffrey 

pine beetle. These beetles attack pines greater than six inches in diameter, particularly 

trees in dense stands. Natural stands dominated by Douglas-fir are similarly impacted by 

the Douglas-fir beetle which affects drought-stressed and wind-damaged stands.

Disturbance Mechanisms: Stand health is also shaped by the types and amount of 

disturbance the stand has experienced over time. Fire, wind, insects and disease, as well 

as past management actions are all mechanisms which influence stand health.

Forest pests occur naturally in stands within the project area, most commonly fir 

engravers and western pine beetles. As stand densities increase and mistletoe infections 

increase, as is happening under current conditions, an environment favorable to increased 

insect infestation is provided. Decreased availability of soil water, which occurs in dense 

stands, reduces a tree’s ability to pitch out attacking insects. Trees weakened by disease 

have similar difficulties.
Silviculture Report Craggy Vegetation Management Project

8

Douglas-fir beetle: The Douglas-fir beetle (Dendroctonus pseudotsugae) is a common 

bark beetle that kills Douglas-fir trees. Douglas-fir beetles prefer to attack trees that are 

injured by fire scorch, defoliation, wind-throw, or root disease. Attacks are most severe in 

unmanaged stands, on trees that are largest in diameter, and in dense stands as exist 

currently in the project area.

Figure 2: Pocket of Beetle Activity in Little Humbug Drainage, 2016

Western pine beetle: The western pine beetle (Dendroctonus brevicomis) is the insect 

enemy that causes the most negative effects to ponderosa pine in California and Oregon. 

Normally, this beetle breeds in windfalls, unhealthy trees, or in trees weakened by 

drought, stand stagnation, or fires, and usually kills the tree (Keen 1952).

Jeffrey pine beetle: The Jeffrey pine beetle (Dendroctonus jeffreyi) is an aggressive and 

at times very destructive enemy to Jeffrey pine. Although it often attacks trees with

apparently healthy growth, it appears to prefer trees that are retarded in growth by 

drought or defoliation. Methods used for control of the western pine beetle are usually 

employed for this species too (Keen 1952).

Wildfire is also an important disturbance mechanism in these stands. The project area is 

considered to be in a mixed severity fire regime, e.g., a fire would naturally result in a 

reduction of the basal area of the dominant vegetation by 20 to 70 percent (Agee 1993). 

More information relative to fire and fuels condition is available in the Fire and Fuels 

Resource Report.
Silviculture Report Craggy Vegetation Management Project

9

Current and Desired Stand Conditions:

Natural Conifer Stands:

Current Condition: About 1,950 acres of the project falls into this category. The stands 

range in elevation from 2,700 feet to 5,400 feet. They are densely stocked averaging 210 

trees per acre. Douglas-fir dominates the species composition. There are lesser amounts 

of ponderosa pine, white fir, sugar pine, and incense cedar as well. The stand density 

index (SDI) for these stands currently averages 265 which is over the threshold of an SDI 

of 230 (Oliver 1995). Some stands on the eastside of the project are composed of 

primarily Douglas-fir with sugar pine and ponderosa pine in the overstory. These mixedconifer stands would have a slightly higher SDI threshold (240-330) given the species 

diversity and the ability of Douglas-fir to persist at higher densities. These stands are 

included in the average stand density index measures.

Figure 3: Area Representative of Natural, Conifer Stands within Project Area

Desired Condition:

The majority of the stands would have an SDI of less than 230 followed by treatment of 

all existing and activity created fuels. This will allow them to remain below the threshold 

for at least 20 years in order to promote forest health and resiliency and to adhere to 

regional forester direction. See the Fire and Fuels Resource Report for more specific fuels 

treatment information. Scattered, larger, dominant Douglas-fir, ponderosa pine, incense

cedar and sugar pine will not have to compete with surrounding trees for sunlight, 

moisture and soil nutrients. Over time, openings will allow natural regeneration to take 

place and a new stand layer can become established and stand heterogeneity can be 

maintained or enhanced.
Silviculture Report Craggy Vegetation Management Project

10

Plantations:

Current Condition: Approximately 3,140 acres of the proposed project comprise this 

category. The stands range in elevation from 2,700 feet to 5,400 feet. They are densely 

stocked with an average of 210 trees per acre. Stands were initiated between 1956 and 

2011 following the Haystack Fire of 1955. These stands have an average SDI of 245. The 

stands are dominated by ponderosa and Jeffrey pines with lesser amounts of Douglas-fir, 

sugar pine, white fir and incense cedar. Inventory data taken in the fall of 2012 reflect 

this species mix. Due to current stand densities and droughty condition, western pine 

beetles have begun killing small (less than a quarter acre) groups of trees with increasing 

frequency over the last five years in the older planted stands and terraced plantations.

Figure 4: Western Pine Beetle Activity on Craggy Mountain within Project Area

Desired Condition: The stand density index would be below 230 to preclude inter-tree, 

competition-induced mortality (Oliver 1995). The incidence of disease would be low. 

Hardwoods would be encouraged. Plantations have been identified as an important 

investment, representing a unique vegetative component and capable of providing future 

opportunities for wildlife habitat and vegetative diversity over time (USDA 1993). Over 

time, openings will be allowed to fill with natural regeneration to enhance species 

diversity and stratify the canopy layers. Stands may begin to take on mid to late seral 

characteristics as tree diameters and heights increase, species diversity increases and 

canopy becomes multi-layered.
Silviculture Report Craggy Vegetation Management Project

11

Figure 5: Desired Future Condition with Mix of Larger Diameter Trees, Natural Regeneration in 

Openings, and Open Canopy Structure for Growing Space and Fire Resilience

Environmental Consequences

For a full description of the alternatives refer to Chapter 2 of the environmental impact 

statement for the Craggy Project.

Alternative 1

Direct and Indirect Effects

Conifer density and competition, as measured by stand density index, will continue to 

increase within stands in the project area from the current value of 265 to 301 after 20 

years. This will encourage increasing tree mortality due to insect infestation.

Table 5: Alternative 1 Effects on Forest Health.

Measure Current Average SDI

for Conifer Stands

20 Year Projected Average 

SDI for Conifer Stands

Stand Density Index 265 301

Target or Desired SDI 230 or less 230 or less

Forest resilience will stagnate as homogenous plantations will continue to occupy the 

landscape with little opportunity for other species, particularly hardwoods, to persist. As 

conifers grow and shade out hardwood species, heterogeneity is reduced over time. 

Conifer species with intermediate levels of shade tolerance that were established after the 

single species plantations will also likely be shaded out by the existing overstory species 

(ponderosa or Jeffrey pine). Increased homogeneity of species may accelerate rates of 

deforestation should an insect outbreak occur, resulting in a less resilient forest 

landscape. Dense plantation stands are also less resilient to wildfire when left 

unmanaged, especially over time, when fuel loading increases following density-related 

or beetle-induced mortality.
Silviculture Report Craggy Vegetation Management Project

12

Cumulative Effects

Since no reasonable foreseeable future actions will occur in this resource’s analysis

area within the 20-year temporal bounding that will have an effect on the 

indicators, adding the effects of this alternative to the effects of past and future actions 

will not produce measureable cumulative effects. The projected stand density index 

increase to 301 after 20 years of no treatment will not be further influenced by any 

reasonably foreseeable future actions within the analysis area.

Alternative 2

Direct and Indirect Effects

In general, prescribed treatments are designed to reduce stand density and the potential 

for extreme fire behavior in order to promote growth and development of stands that are 

healthier, structurally diverse, and more resilient to insects, disease, and fire. Both types 

of thinning (thinning with and without product removal) will reduce tree density and the 

likelihood of western pine beetle outbreaks. This alternative will result in an SDI of 148 

in the short term, and 200 in the long term.

Stands will be thinned and trees will be removed from some of the treated stands as 

biomass or saw logs. Trees will be harvested using skyline cable yarding or tractor 

yarding systems. Hardwoods, in general, would be cultured to maintain them as an 

integral part of the stands.

The stands would be thinned from below at a variable spacing. Trees in the smaller size 

classes would more frequently be cut than larger trees. Scattered, larger, dominant 

ponderosa pine, incense cedar, sugar pine or Douglas-fir found singly or in groups will 

generally be retained and in some instances cultured by removing trees that are 

competing for sunlight, moisture and soil nutrients. The large tree culturing will increase 

individual tree resistance to insect attack, retain for a longer period of time more of the 

tree’s live crown, and in some instances, increase the growth rate of the tree. This 

culturing will create small gaps in the canopy of the stand. Hardwoods, where they exist, 

will be retained and their growth encouraged by thinning around them. Portions of the 

stands will have a fair component of conifers less than ten inches in diameter. Where no 

larger, nearby conifers (greater than ten inches in diameter) exist, these thickets will be

thinned without forest product removal. In areas where there are healthy, vigorous trees 

nearby, these smaller trees would be removed. A variety of methods to treat activitygenerated fuels may include whole tree yarding, hand piling and pile burning, or 

underburning; depending on the geographic location and quantity of fuel. In stands where 

off-site stock was planted, naturally regenerated conifers will be chosen for retention and 

wider spacing incorporated to retain those trees that have the potential to achieve the 

desired sizes for late successional old-growth stand structure.

Maintaining a stand density index of less than 230 for the next 20 to 30 years will 

promote stand health and reduce the likelihood of large scale insect and disease 

outbreaks. Managing activity-generated fuels following thinning treatments in 

conjunction with the removal of forest products from some thinning units will also 

decrease negative effects associated with a potential future wildfire.
Silviculture Report Craggy Vegetation Management Project

13

Of the examined stands, 50 percent of the stands have SDIs over the 55 percent of 

maximum SDI and are in the “zone of imminent mortality”. Thirteen percent of stands 

are currently in the “moderate density” class which may be a reflection of quantity and 

location of plot data as well as low site quality. The remaining stands are classified as 

high density with SDI values falling between 34 and 55 percent of maximum stand 

density index.

Table 6: Alternative 2 Effects on Forest Health.

Measure

Current

Average SDI

for Conifer 

Stands

Post-Treatment 

Average SDI for 

Conifer Stands

20 Year Projected 

Average SDI for 

Conifer Stands

Stand Density Index 265 148 200

Target or Desired SDI 230 or less 230 or less 230 or less

According to modeled outcomes, there will be an increase of stand heterogeneity (species 

diversity) with this alternative. Heterogeneity of species can be evaluated qualitatively by 

comparing modeled outcomes of species diversity with the unit-specific written 

prescriptions. There is a modest shift in species composition without specifying a 

preference for particular species within the model. Silvicultural prescriptions address sitespecific species preference, including hardwoods, to retain diversity on the landscape. 

This specification will result in stand heterogeneity where the site is capable of 

supporting diverse species. Indirect effects of treating stands as described in Alternative 2 

will result in the maintenance or enhancement of species diversity where compatible with 

site conditions.

Cumulative Effects

Past actions are reflected in the discussion of the affected environment. No reasonably

foreseeable future actions are expected in treatment areas that would impact forest health 

and forest resiliency. Adding the beneficial effects on forest health and resiliency of 

Alternative 2 to the effects of past, present and reasonably foreseeable future actions is 

not expected to have additional effects on the measurement indicators.

Alternative 3

Direct and Indirect Effects

The effects of Alternative 3 are the same as those described in Alternative 2 for the stands 

that are proposed for treatment. Eight stands in this alternative differ in silvicultural 

prescription from Alternative 2 and will have slightly different effects than Alternative 2. 

For stands not treated, effects will be the same as Alternative 1.
Silviculture Report Craggy Vegetation Management Project

14

Table 7: Alternative 3 Effects on Forest Health.

Measure

Current 

Average SDI for 

Conifer Stands

Post-Treatment 

Average SDI for 

Conifer Stands

20 Year Projected 

Average SDI for 

Conifer Stands

Stand Density Index 265 153 299

Target or Desired SDI 230 or less 230 or less 230 or less

Alternative 3 only treats about half as many plantations as Alternative 2. This leaves 

hundreds of acres of plantations in an overstocked condition susceptible to beetle 

outbreaks and advanced mortality. Stand heterogeneity is not encouraged within the 

untreated stands.

Five stands: 136-2, 136-21, 136-25, 136-26 and 138-23 (totaling 174 acres) would be 

changed from thinning with product removal to thinning without product removal. Two 

additional stands: 134-240 and 134-242 (totaling 45 acres) have a reduction in acres

proposed for forest product removal. This results in only eight percent of Stand 134-240 

meeting the desired condition and 65 percent of Stand 134-242 meeting the desired 

condition. Thinning without product removal results in a smaller reduction in the stand 

density index, which makes this method less effective at increasing stand health and 

resiliency. Stand density will be reduced below the threshold of concern (SDI of 230) for 

susceptibility to bark beetles in the short term, but the efficacy of treatment will not make 

it to the 20 year standard. The average projected SDI 20 years after treatment for these 

stands was 268. Although a similar number of acres will be treated in both alternatives, 

fewer acres will meet the purpose and need for stand resiliency and forest health than in 

Alternative 2 due to the decrease in acres of thinning with product removal. The long 

term effectiveness of the prescriptions for Alternative 3 treatments is not met on 

approximately eight percent of the stands. All proposed treatment in this alternative will 

result in an SDI of 153 in the short term, and 299 in the long term.

Cumulative Effects

Past actions are reflected in the discussion of the affected environment. No reasonably

foreseeable future actions are expected in treatment areas that would impact forest health 

and forest resiliency. Adding the beneficial effects on forest health and resiliency of 

Alternative 3 to the effects of past, present and reasonably foreseeable future actions is 

not expected to have any additional effects on the measurement indicators.

Comparison of Alternatives

Alternative 1 would not increase forest health or resilience. Alternative 2 treats the 

greatest number of acres for forest health and provides the greatest number of acres of 

forest resilience measured by modeled heterogeneity of tree species. Alternative 2 also 

includes the larger number of treatments that have a longer period of effectiveness; this is 

beneficial for getting stands on a trajectory towards the desired conditions which include 

resilience to insects and disease, resilience to wildfire and improved stand health 

(reduced stand density to optimize growing conditions). Alternative 3 proposes a similar 

number of acres for treatment but leaves forest health on many acres of plantations in an 

overstocked condition (susceptible to beetle outbreaks and advanced mortality) and 
Silviculture Report Craggy Vegetation Management Project

15

without improved forest heterogeneity. Alternative 3 would have short-term benefits but 

would not meet direction for 20-year effectiveness of treatment as displayed in Table 8.

Table 8: Comparison of Effects on Forest Health.

Measures

Affected 

Environment: 

Existing 

Conditions

Alternative 

1: 20 Yrs. 

No 

Treatment

Alternative 

2: Post 

Treatment

Alternative 

2: 20 Yrs. 

Post 

Treatment

Alternative 

3: Post 

Treatment

Alternative 

3: 20 Yrs. 

Post 

Treatment

Stand Density 

Index 265 301 148 200 153 299

Compliance with law, regulation, policy, and the Forest Plan

All alternatives comply with law, regulation, policy and the Forest Plan as noted in the 

Forest Plan Consistency Checklist, available on the project website.
Silviculture Report Craggy Vegetation Management Project

16

Literature Cited

Agee, James K. 1993. Fire Ecology of Pacific Northwest Forests. Covelo, CA: Island Press. 493 

p.

Keen, F.P. 1952. Insect Enemies of Western Forests. Miscellaneous Publication 273. 

Washington D.C. U.S. Department of Agriculture. 280 p.

Keyes, C.R. and O’Hara, K.L. 2002. Quantifying stand targets for silvicultural prevention of 

crown fires. Journal of Applied Science 17(2): 101-109.

Oliver, W.W. 1995. Is Self-thinning in Ponderosa Pine Ruled by Dendroctonus Bark Beetles? 

Pages 213-218 in Lane G. Eskew, comp. 1995. Forest Health through SilvicultureProceedings of the 1995 National Silviculture Workshop; 1995 May 8-11; Mescalero, 

New Mexico. General Technical Report. RM-GTR-267. Fort Collins, CO: US 

Department of Agriculture, Forest Service, Rocky Mountain Range and Experiment 

Station. 246 p.

Reineke, L.H. 1933. Perfecting a stand-density index for even aged forests. U.S.D.A. Journal of 

Agricultural Research, Washington DC, Vol.46. No. 7, 1933: 627-638.

Shiflet, T.N., ed. 1994. Rangeland Cover Types of the United States. Society for Range 

Management. Denver, Colorado.

USDA Forest Service. 1993. Klamath National Forest, Humbug Landscape Analysis and Design. 

Yreka, CA: U.S. Department of Agriculture, Forest Service, Klamath National Forest.

USDA Forest Service. 2004. Pacific Southwest Regional Forester letter of July, 14, 2004.

Vallejo, CA.