A Landscape Plan Based on

Historical Fire Regimes for a

Managed Forest Ecosystem:

the Augusta Creek Study

John H. Cissel, Frederick J. Swanson, Gordon E. Grant,

Deanna H. Olson, Stanley V. Gregory, Steven L. Garman,

Linda R. Ashkenas, Matthew G. Hunter, Jane A. Kertis,

James H. Mayo, Michelle D. McSwain, Sam G. Swetland,

Keith A. Swindle, and David O. Wallin

1600 AD

1995 AD

1800 AD

2195 AD

United States

Department of

Agriculture

Forest Service

Pacific Northwest

Research Station

General Technical

Report

PNW-GTR-422

May 1998

Young Mature Old
JOHN H. CISSEL is the Cascade Center research coordinator, JAMES H. MAYO is a

silviculturist, MICHELLE D. McSWAIN is a hydrologist, and SAM G. SWETLAND is a

fire and fuels specialist, Blue River Ranger District, P.O. Box 199, Blue River, OR

97413; FREDERICK J. SWANSON is an ecosystem team leader, GORDON E.

GRANT is a research hydrologist, and DEANNA H. OLSON is a research biologist,

Forestry Sciences Laboratory, 3200 SW Jefferson Way, Corvallis, OR 97331;

STANLEY V. GREGORY is a professor, LINDA R. ASHKENAS is a research associate, and KEITH A. SWINDLE is a faculty research assistant, Oregon State University,

Department of Fisheries and Wildlife, Nash Hall, Corvallis, OR 97331; STEVEN L.

GARMAN is an assistant professor and MATTHEW G. HUNTER is a wildlife ecologist, Oregon State University, College of Forestry, Forest Science Department,

Corvallis, OR 97331; JANE A. KERTIS is an ecologist, Siuslaw National Forest,

Corvallis, OR 97339; and DAVID O. WALLIN is an assistant professor, Huxley College of Environmental Studies, Western Washington University, Bellingham, WA

98225.

Authors
Abstract

Summary

Introduction

Cissel, John H.; Swanson, Frederick J.; Grant, Gordon E.; Olson, Deanna H.;

Stanley, Gregory V.; Garman, Steven L.; Ashkenas, Linda R.; Hunter, Matthew

G.; Kertis, Jane A.; Mayo, James H.; McSwain, Michelle D.; Swetland, Sam G.;

Swindle, Keith A.; Wallin, David O. 1998. A landscape plan based on historical

fire regimes for a managed forest ecosystem: the Augusta Creek study. Gen. Tech.

Rep. PNW-GTR-422. Portland, OR: U.S. Department of Agriculture, Forest Service,

Pacific Northwest Research Station. 82 p.

The Augusta Creek project was initiated to establish and integrate landscape and

watershed objectives into a landscape plan to guide management activities within a

7600-hectare (19,000-acre) planning area in western Oregon. Primary objectives

included the maintenance of native species, ecosystem processes and structures,

and long-term ecosystem productivity in a federally managed landscape where

substantial acreage was allocated to timber harvest. Landscape and watershed

management objectives and prescriptions were based on an interpreted range of

natural variability of landscape conditions and disturbance processes. A dendrochronological study characterized fire patterns and regimes over the last 500 years.

Changes in landscape conditions throughout the larger surrounding watershed due to

human uses (e.g., roads in riparian areas, widespread clearcutting, a major dam, and

portions of a designated wilderness and an unroaded area) also were factored into

the landscape plan. Landscape prescriptions include an aquatic reserve system

comprised of small watersheds distributed throughout the planning area and major

valley-bottom corridor reserves that connect the small-watershed reserves. Where

timber harvest was allocated, prescriptions derived from interpretations of fire regimes

differ in rotation ages (100 to 300 years), green-tree retention levels (15- to 50-

percent canopy cover), and spatial patterns of residual trees. General prescriptions

for fire management also were based on interpretations of past fire regimes. All these

prescriptions were linked to specific blocks of land to provide an efficient transition to

site-level planning and project implementation. Landscape and watershed conditions

were projected 200 years into the future and compared with conditions that would

result from application of standards, guidelines, and assumptions in the Northwest

Forest Plan prior to adjustments resulting from watershed analyses. The contrasting

prescriptions for aquatic reserves and timber harvest (rotation lengths, green-tree

retention levels, and spatial patterns) in these two approaches resulted in strikingly

different potential future landscapes. These differences have significant implications

for some ecosystem processes and habitats. We view this management approach as

a potential postwatershed analysis implementation of the Northwest Forest Plan and

offer it as an example of how ecosystem management could be applied in a particular

landscape by using the results of watershed analysis.

Keywords: Landscape ecology, landscape management, landscape planning, fire

history, range of historical variability, watershed analysis, fire ecology.

There is a growing awareness that to sustain human uses of an ecosystem, the

ecosystem itself must be sustained. For the public forest lands considered here, we

interpreted the goal of sustaining ecosystems to mean maintaining native species,

ecosystem processes and structures, and long-term ecosystem productivity. In the

Augusta Creek project, we developed a landscape plan to achieve these goals based

on historical disturbance regimes and landscape conditions. A premise of this approach is that native species have adapted to the range of habitat patterns resulting

from historical disturbance events, and the probability of survival of these species is
reduced if their environment is maintained outside the range of historical conditions.

Similarly, ecological processes, such as nutrient and hydrologic cycles, have historically functioned within a range of conditions established by disturbance and successional patterns. Management activities that move structures and processes outside

the range of past conditions may adversely affect ecosystems in both predictable and

unforeseen ways. Another key component of our management approach recognized

that existing conditions must be integrated with this historical template to meet longterm objectives. Human uses have substantially altered conditions in the project area

and in the surrounding watersheds.

A fire history study of the last 500 years revealed the fire patterns within the planning

area. Plot-level data were used to map 27 of these fire events. The fire-event maps

and field observations were used to describe and map characteristic fire frequencies,

severities, and spatial patterns of nine general fire regimes. The fire-event maps also

were used to reconstruct and analyze vegetation patterns within the same 500-year

period.

Several approaches were used to analyze the aquatic ecosystem and hillslope-tostream disturbances. Landslide and debris-flow occurrences and relative potential for

future occurrences were interpreted from aerial photographs, maps of existing conditions, and field surveys. Relative susceptibilities of the watershed to rain-on-snow

peak flows and contributions to summer baseflows were assessed. A time-series of

aerial photographs spanning the past 40 years were used to assess riparian vegetation dynamics and disturbance history.

Both prehistoric and contemporary human uses were described and mapped. Prehistoric and historical data for the general area were employed to construct a probability-of-past-use map and narrative. Current human uses include hiking (two trails),

camping (three campgrounds), angling, hunting, and harvest of timber and special

forest products.

In the first step, “special area reserves” allocated in the Willamette National Forest

Plan, as amended by the Northwest Forest Plan, were delineated. Prescriptions for

these areas generally entail a “natural” succession approach. Prescribed natural fires

were encouraged where feasible.

The remainder of the planning area was then subdivided into zones with similar

ecological conditions and disturbance regimes, termed “landscape areas.” General

prescriptions were developed for each area based on the fire regime and the condition of the vegetation. Rotation ages (100 to 300 years) were derived from fire frequency information, green-tree retention levels (15 to 50 percent) were based on fire

severity interpretations, and guidelines for patch size came from historic fire and

patch size analyses. Prescriptions for low-intensity fires were derived from fire regime

descriptions and integrated with timber harvest patterns and schedules.

In the third step, “aquatic reserves” were established to ensure that the full range of

objectives in the Northwest Forest Plan would be met, with particular attention given

to the Aquatic Conservation Strategy (USDA and USDI 1994). These reserves were

based, in part, on the type and intensity of upslope management in the local landscape area and were designed to reflect general patterns of disturbance processes.

Small-watershed reserves were positioned throughout the basin, such that different

habitat types and topographic-disturbance regions were represented in headwater,

Phase 1—Analysis

of Conditions,

Processes, and Uses

Phase 2—Landscape

Plan
midbasin, and lower portions of the drainage, and such that species of concern (e.g.,

torrent salamanders [Rhyacotriton spp.]) were protected. Areas of high streamdrainage density and headwall areas were favored for reserve placement. Steep,

unstable areas with simple drainage patterns and long debris flow runouts also were

placed in reserves, as were two unstable hillslope areas.

Aquatic reserves also included large riparian corridors along both sides of all major

streams. These areas, in which older forests survived past fire events, parallel the

stream and include the stream, adjacent flood plains, and riparian vegetation. These

corridors link the small-watershed reserves.

Maps of future landscape and watershed conditions were developed by simulating the

growth of existing forest stands with a simple stand-age model in a Geographical

Information System (GIS). Following timber cutting, blocks were reset to specific

stand conditions, according to a timber harvest schedule determined by the landscape prescriptions for the area, and growth was simulated again until the next

scheduled cutting. A set of maps depicting future landscape conditions show a

gradual change in the landscape from the relatively fragmented existing forest to one

dominated by larger blocks and containing a wider array of stand types. By year 100,

the future landscape appeared significantly different from the existing landscape and

continued to gradually change before stabilizing in year 200.

We evaluated this landscape management approach (which we termed “Landscape

Plan”) by comparing it to a future landscape generated by applying standards, guidelines, and assumptions from the Northwest Forest Plan before adjustments were

made to it as a result of watershed analysis (termed “Interim Plan”). The Interim Plan

was characterized by the extensive Riparian Reserves buffering all streams and an

80-year timber harvest rotation on most upland areas where timber harvest was

allocated. Harvest areas maintained a relatively light level of green-tree retention

(15 percent).

The Interim Plan leads to a high-contrast forest pattern within areas managed for

timber. Old forests develop along all lower slope positions, and upper slope positions

contain relatively young, structurally simple stands. Maximum protection of aquatic

systems from timber harvest was provided by Riparian Reserves on all streams.

Edge-using terrestrial species also were found to benefit from this design.

The Landscape Plan results in a greater range of stand structures and larger patches.

In addition, higher levels of habitat features, such as green trees, snags, and downed

logs, would be found in patches where timber harvest occurs. This results from the

larger timber harvest blocks, longer rotations, and higher levels of green-tree retention in areas where timber harvest is allocated. These features were felt to benefit

many amphibians, birds, and mammals.

Little difference between approaches was evident for many processes and species.

Disturbance processes (e.g., landslides and flood events), stream flows, aquatic

processes, species that use a wide range of habitats, and long-term timber yields

were very similar in the two approaches.

The development of a spatially and temporally explicit landscape plan lays the

groundwork for a focused and efficient project-level planning process. The type and

timing of future management activities can be established by comparing existing

Phase 3—Projection

of Future Conditions

Phase 4—Evaluation

of Effects

Link to Project-Level

Planning
stand conditions with projected future landscape patterns. For example, near-term

timber sale planning can begin with the blocks scheduled to be in early seral conditions at the end of the first 20-year time step. Detailed prescriptions can be developed

for these blocks with confidence that management activities contribute to long-term

landscape objectives. An appropriate schedule of prescribed fire, natural or introduced, also can be linked to the overall landscape block schedule and to reserve

objectives.

We view this management approach as a potential postwatershed analysis implementation of the Northwest Forest Plan. Although the exact mechanisms for adjusting the

Northwest Forest Plan remain unclear, changes in the plan were anticipated to follow

from watershed analysis. We hope this analysis can help identify useful ways to

improve implementation of the Northwest Forest Plan and better link results of

watershed analysis with planning.

Relation to

Northwest Forest

Plan
Contents 1 Introduction

1 Goals

3 General Ecosystem Management Objectives and Assumptions

5 Area Description

6 General Analytical Process

7 Larger Scale Context

8 Phase 1—Analysis of Past and Present Conditions and Processes

8 Fire History

9 Landscape Structure

16 Hydrology

17 Mass Movement

20 Riparian Habitat and Fauna

26 Human Uses

27 Phase 2—Landscape Plan

29 Special Area Reserves

29 Landscape Areas

36 Aquatic Reserves

38 Phase 3—Projection of Future Conditions

38 Landscape Blocks

39 Future Landscape Conditions

42 Phase 4—Evaluation

42 Interim Plan

45 Comparison of Scenarios

46 Landscape Structure

52 Hydrology

54 Debris Slides and Flows

55 Amphibians

57 Fish and Selected Aquatic Taxa

59 Birds and Mammals

61 Northern Spotted Owls
63 Timber Production and Operational Feasibility

64 Wildfire

65 Windthrow

66 Insects and Diseases

67 Links to Project-Scale Planning

69 Discussion

69 Key Elements of This Approach

71 Limitations of Analysis

71 Application to Other Landscapes

72 Policy Implications

74 Adaptive Management

74 Human Values

75 Future Work

75 Conclusion

76 Acknowledgments

76 Literature Cited
1

Introduction

Goals

A tiered approach to ecosystem management is gradually emerging in the Pacific

Northwest to address biological and social issues at appropriate scales (Grumbine

1994). Each scale has distinctive biological and social issues, relevant ecological

principles and concepts, and essential components of management strategies (table

1). Analyses and decisions at one scale influence those at other scales. Analyses

and plans at local levels receive objectives and constraints from regional and subregional management plans. In turn, analyses and decisions from local levels provide

site- or landscape-specific information for subsequent iterations of regional and subregional analyses and decisions. Such a feedback loop is essential for adaptive management across ecosystems being managed at scales of an individual hectare to

habitat for a regionwide range of critical species.

The Northwest Forest Plan (USDA and USDI 1994) is based on a regional-scale

analysis for forest and riverine ecosystems (Forest Ecosystem Management Assessment Team [FEMAT] 1993). The plan contains three major components:

1. A set of land allocations (Late-Successional Reserves, Key Watersheds, Adaptive

Management Areas, Riparian Reserves, and Matrix lands).

2. An extensive set of standards and guidelines governing management activities.

3. Requirements for a watershed analysis process.

Through this plan, ecosystem management objectives and constraints have been

established at the regional level that strongly influence the range of options available

for local-level analyses and activities.

The watershed analysis process is meant to function at a scale between the Northwest Forest Plan (USDA and USDI 1994) and site-specific actions. Past, current,

and potential future conditions and trends are to be assessed at the watershed scale.

Watershed restoration and monitoring projects are recommended, and information

from watershed analyses is to be used to develop priorities and support management

decisions at all levels (USDA and USDI 1994). Watershed analysis is required before

adjustments are made in Riparian Reserve locations and widths (USDA and USDI

1994). The Federal guide for watershed analysis (Regional Ecosystem Office [REO]

1995) provides general direction for watershed analyses on federally managed public

lands.

This paper describes a case study integrating results from a watershed analysis into a

spatially and temporally specific management plan for one watershed: Augusta Creek,

which is located in the central west side of the Cascade Range of Oregon. In this critical respect, the case study differs from the watershed analysis procedures prescribed by REO (1995) and from most watershed analyses recently conducted

throughout the region. Upslope management prescriptions and Riparian Reserves are

recast at the watershed level based on information in a watershed-scale analysis.

Elements of the landscape plan include variable-length rotations, variable levels of

green-tree retention, and a modified approach to Riparian Reserves.

To prepare this case study, we first developed and demonstrated a landscape management strategy in a managed forest landscape based on historical disturbance regimes

and patterns. Second, we synthesized a landscape-specific understanding of both

aquatic and terrestrial ecosystems into an integrated management plan at the watershed scale. The resulting upslope management regime and aquatic reserve system
2

Table 1—Examples of components of ecosystem management at regional, watershed-landscape, and

stand-project scales

Level Component Explanation

Regional (107 hectares) Biological Sustain species with ranges

over the region.

Ecological principles-concepts Species are dependent on the mix of habitat

needed for critical components of life history;

e.g., forage, rearing, dispersal habitat.

Social Regional economy; Federal Government role

in transition related to change in wood supply.

Example of management strategy Regional conservation strategy embodying

reserve systems, standards and guidelines, etc.

Watershed-landscape Biological Sustain species through preservation or

 (104 - 106 hectares) management, or both, of terrestrial and

aquatic habitats.

Ecological principles-concepts Disturbance regimes strongly control

structure and function of ecosystems at

landscape-watershed scale.

Social Stability of local communities.

Example of management strategy Landscape-watershed management plan

based on historical variability of disturbance

regimes.

Stand-project Biological Sustain productivity and habitat for species

 (100 - 102 hectares) with limited range.

Ecological principles-concepts Certain processes are dependent on specific

species or environmental conditions, and

certain species are dependent on specific

habitat elements.

Social Use of specific sites; public involvement in

project planning.

Example of management strategy Retention of coarse woody debris and live

trees at levels necessary to meet habitat and

ecological process objectives.

Source: Cissel and others 1994.
3

are interdependent and meant to be jointly evaluated and implemented. Third, we

placed landscape and watershed objectives in the context of a regional plan (USDA

and USDI 1994) and linked those objectives to stand and site-level prescriptions.

This paper documents the concepts, methods, and potential results of a landscape

management approach developed for Augusta Creek. The consequences of actually

managing under such an approach are largely unknown, but the approach was developed in sufficient detail that an informed evaluation of effects was made (phase 4). A

useful reference point for evaluating the potential effects of this approach is the “prewatershed analysis” landscape from the Northwest Forest Plan; i.e., the landscape

that would result from literal application of the standards, guidelines, and assumptions

underlying the timber harvest levels in the Northwest Forest Plan (Probable Sale

Quantity [PSQ]) unmodified by watershed analysis. These two approaches are compared in the latter part of the paper.

A general goal of ecosystem management is to sustain ecosystems while providing

for compatible levels of human use (Wood 1994). There is a growing awareness that

to sustain human uses of the ecosystem, the ecosystem itself also must be sustained.

We interpreted the goal of sustaining forest ecosystems on public lands to mean

maintaining native species, ecosystem processes and structures, and long-term ecosystem productivity. In the Pacific Northwest, and elsewhere, production of wood fiber

is a significant human use of forest lands. The balance among forest uses remains a

contentious issue.

We currently lack the knowledge to accurately and completely state how native

species and ecosystem processes and productivity can be sustained. If we knew all

the relations among components of the ecosystem and human uses, a rational

planning process might confidently define a range of possible management alternatives to sustain the ecosystem and provide for human uses. More realistically, partial

ignorance and inevitable surprise inherently characterize our understanding of human

interactions with ecosystems (Faber and others 1992). In this case study, we therefore elected to follow a relatively conservative approach to human use of ecosystems,

rely on past conditions and historical patterns as guides for future management

strategies, recognize the need for restoration of some ecosystems, and recommend

an adaptive management approach.

We developed a landscape management strategy where past disturbance regimes

and landscape conditions provided key reference points for future landscape objectives. A premise of this approach is that native species are adapted to the range of

habitat patterns resulting from historical disturbance events over the last 500 years,

and the probability of survival of these species is reduced if their environment lies

outside the range of historical conditions for a prolonged time (Swanson and others

1993). Similarly, ecological processes, such as those involved in nutrient and hydrologic cycles, have functioned historically within a range of conditions established by

disturbance and successional patterns. Operating outside the range of past conditions may affect these processes in unforeseeable and perhaps undesirable ways.

The threatened or sensitive status of many species in the Northwest, including the

northern spotted owl (Strix occidentalis), marbled murrelet (Brachyramphus marmoratum), certain anadromous fish stocks, and the numerous old-growth-associated

species identified in the Northwest Forest Plan (USDA and USDI 1994: table C-3,

p. C-49 to C-61) may be partially the result of ecosystems in conditions outside or

near the extremes of past conditions.

General Ecosystem

Management

Objectives and

Assumptions
4

Our ability to use historical conditions and disturbance regimes as templates for future

management plans was limited in several respects: First, in technical issues, with

interpreting of past events limited by the accuracy of historical assessments; for

example, fire history analyses were limited by the length of the available record. An

inaccurate picture of fire frequency may be obtained if the period of record is short

relative to fire frequency. Second, present and future conditions may be far outside

the range of historical conditions due to factors unlikely to be affected by future

management strategies (e.g., the effects of exotic species, existing engineered

structures, climate change). And third, society may desire conditions that differ greatly

from historical conditions. For example, large disturbance events, such as a 50 000-

hectare (120,000-acre) fire, have occurred historically; but the short-term effects of

such an event on wildlife, watershed, and recreational values may be viewed as

unacceptable by many.

Existing conditions are far different from historical conditions owing to past human

uses, and the implications of these environmental alterations must be integrated with

the historical template to meet our objectives. In the South Fork of the McKenzie

River watershed, where Augusta Creek lies (fig. 1), Cougar Dam and Reservoir have

been constructed, hundreds of miles of roads have been built, hundreds of even-aged

plantations have been established in place of native forests, and nonnative species

have been introduced.1 These activities have modified habitat and ecosystem

processes such that some species’ future existence in the area may be threatened

(e.g., spotted owl and bull trout [Salvelinus confluentus]). In other portions of the

South Fork watershed, wilderness and unroaded areas have been designated. A

1Willamette National Forest. 1994. South Fork watershed analysis.

Eugene, OR: U.S. Department of Agriculture, Forest Service, Willamette

National Forest. [unpaged]. Administrative report. On file with: Blue River

Ranger District, Willamette National Forest, Blue River, OR 97413.

Figure 1—Location of the Augusta Creek project area.
5

relatively effective fire suppression policy has been in place for several decades

throughout the watershed. Large-scale habitat modifications in combination with

societal expectations (e.g., that native species be maintained, timber produced, and

fire suppressed) limit the degree to which past patterns can be applied in future

management.

Given our current incomplete understanding of habitat requirements and ecosystem

processes, reliance on the pattern and structure of historical landscapes as key

reference points nevertheless can provide a practical approach to ecosystem management in many cases. We elected to use an understanding of historical disturbance

regimes, primarily fire, as a basic management template. This template was then

adjusted for existing conditions, differences between active forest management and

historical disturbances, and the presence of specific social objectives. The general

concept of using historical disturbance regimes as a template for landscape management is being explored in various settings across the country (e.g., Baker 1992, Hardy

and Arno 1996, Hunter 1993, Mladenoff and others 1993, Morgan and others 1994,

Swanson and others 1993) and internationally (Stuart-Smith and Hebert 1996).

Emulating patterns of historical disturbance regimes in landscape plans is one of

several alternative approaches. A second approach is the intensive use of reserves,

corridors, and matrix designations common in conservation biology (Noss and

Cooperrider 1994). A third approach, common in intensive forestry, involves simple

dispersed or aggregated cutting on a fixed rotation length. The Augusta Creek project

is intended, in part, to provide a test of alternative approaches through comparison of

the reserve-matrix system emphasized by the Northwest Forest Plan with the disturbance-based approach developed for the Augusta area.

The 7600-hectare (19,000-acre) Augusta project area lies in steep, dissected mountains of the west side of the central Cascade Range of Oregon. Located in the South

Fork of the McKenzie River watershed (fig. 1), the project area is typical of much of

the National Forest land along the west side of the Cascade Range. Elevation ranges

from 700 to 1740 meters (2,300 to 5,700 ft). A seasonal snowpack usually develops

above 1100 meters (3,500 ft), and a transient snowpack frequently forms and melts at

lower elevations. Peak flows due to rapid snowmelt during rain-on-snow events are

believed to be a primary cause of channel-altering floods in this area (Berris and Harr

1987; Coffin and Harr 1992; Harr 1981, 1986).

Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) is the dominant tree species over

most of the planning area, with western hemlock (Tsuga heterophylla (Raf.) Sarg.)

and western redcedar (Thuja plicata Donn ex D. Don) the most common associates.

Grand fir (Abies grandis (Dougl. ex D. Don)) intermingles on drier sites, and Pacific

silver fir (Abies amabalis Dougl. ex Forbes) and noble fir (Abies procera Rehd.)

dominate colder sites. Mountain hemlock (Tsuga mertensiana (Bong.) Carr.) is

common above 1500 meters (5,000 ft). Old forests (>200 years in age) and complex

stand structures resulting from multiple wildfire events prevail over a large portion of

the planning area. A series of high-elevation dry meadows occurs along the ridgetops

forming the southern boundary of the planning area. Many of these meadows are

currently undergoing succession to conifers. Two unroaded reserves span the northand south-bounding ridges of the planning area, while much of the lands between fall

within a mix of land-use designations that prescribe timber harvest (USDA 1990,

USDA and USDI 1994). Plantations regenerated after clearcutting are dispersed

throughout most of the roaded area.

Area Description
6

Our analytical process involved four sequential phases (fig. 2). Results from any one

phase, however, could trigger a return to a preceding phase. The larger context of the

surrounding watersheds provided important context for each of these phases.

In the first phase (refer to fig. 2), past and current conditions, processes, disturbance

regimes, and human uses were analyzed. A fire history study was conducted to

describe and map past fire regimes. This analysis was similar to watershed analyses

being implemented as part of the Northwest Forest Plan.

In the second phase, prescriptions guiding future management actions were developed from the results of phase one. These objectives were based on the range of

variability in past habitat conditions as interpreted from studies of the histories of fire

General

Analytical

Process

Phase 1

Phase 3

Phase 4

Phase 2

Analysis

• Existing conditions

• Disturbance regimes

• Range of historical variability

• Human uses

Larger Scale Context

•Conditions in surrounding watersheds

•Direction from Northwest Forest Plan

Landscape Management Approach

• Zoning (special area reserves, landscape areas, aquatic reserves)

• Objectives (e.g., proportion of stand types, spatial pattern)

• Prescriptions (e.g., rotation age, retention level, fire frequency)

Spatial Representation

• Landscape blocks

Temporal Representation

• Long-term scheduling

Evaluate Results

• Landscape structure

• Vertebrate habitat

• Aquatic ecosystems

• Ecosystem processes

• Human uses

Site-level Planning

Figure 2—General analytical process used to develop the Augusta Creek Landscape Plan.
7

and other disturbances and modified where existing conditions were judged to be

outside the range of past conditions. In areas where timber cutting was allocated,

landscape prescriptions established cutting frequencies, intensities, and the desired

spatial pattern.

In the third phase, landscape objectives and prescriptions were used to develop

spatially and temporally explicit portrayals of potential future landscape and watershed conditions. Spatial pattern objectives were used to map areas, termed “landscape blocks,” where timber cutting will occur. These blocks were used for long-term

scheduling, each having a prescribed frequency and intensity of cutting. Maps of

landscape structure were then produced for each 20-year time step.

In the fourth phase, maps of landscape structure were compared to conditions that

would result from application of standards, guidelines, and assumptions in the Northwest Forest Plan, prior to any modifications that might result from watershed analysis

and related plan adjustments. Landscape structure, plant and animal habitat, ecosystem processes, and human uses were evaluated, by using both quantitative and

qualitative methods.

The resulting landscape management objectives and prescriptions provide a direct

link to project-scale planning for timber sales, prescribed fire, silvicultural activities,

and restoration or recovery projects. The type and timing of future activities can be

established by comparing existing conditions to the projected trajectory of future

conditions.

The South Fork of the McKenzie River watershed provides an important context for

interpreting conditions and processes within the Augusta Creek area (fig. 1). Cougar

Dam and Reservoir have blocked or impeded migration and movement of some

aquatic and terrestrial biota, interrupted downstream movement of wood and sediment, and significantly altered stream flow below the dam since the mid-1960s. Bull

trout, a threatened species in parts of its range and considered sensitive by many fish

biologists, are known to use the main stem of the South Fork but are prevented from

mixing with the main McKenzie River population by Cougar Dam. The bull trout

population in the South Fork appears to be small and subject to local extirpation if

conditions degrade and movement between the McKenzie River and the upper South

Fork continues to be blocked by Cougar Dam (see footnote 1). The cold, spring-fed

Roaring River provides important spawning habitat for bull trout (see footnote 1).

Vegetation conditions vary considerably within the South Fork watershed. Most lands

on the east side of the South Fork above Cougar Dam are in the Three Sisters

Wilderness (51 percent of the South Fork watershed). The wilderness is dominated

by mature forest, with pockets of older and younger forest. The western portion of the

South Fork watershed has been extensively roaded and clearcut over the last 40

years. Downstream from Augusta Creek, clearcutting has progressed to the point

where even-aged plantations dominate the landscape with small fragments of older

forest remaining in places. Above the confluence of Augusta Creek and the South

Fork, the western slopes contain mostly mature and older forests perforated by

numerous small, dispersed clearcuts and plantations. The high density of roads in the

western portion of the watershed has resulted in increased sedimentation and altered

hydrologic functions in some areas (see footnote 1). Plantations regenerated after

clearcutting occupy many riparian areas, resulting in reduced source areas for future

large wood input to streams.

Larger Scale

Context
8

The regional management context set by the Northwest Forest Plan (USDA and USDI

1994) designates most of the South Fork of the McKenzie River watershed as a Tier 1

Key Watershed to provide primary habitat for bull trout. Timber harvest is expected to

occur within a portion of the South Fork watershed, subject to findings from a watershed analysis indicating that harvest is compatible with objectives of the Aquatic

Conservation Strategy of the Northwest Forest Plan. A Late-Successional Reserve in

the northeast portion of the watershed mostly overlaps with the Three Sisters Wilderness but also contains additional lands (7 percent of the South Fork watershed)

adjacent to the wilderness. This reserve and others allocated throughout the range of

the northern spotted owl are intended to provide primary nesting and foraging habitat

for the northern spotted owl. The Augusta area is expected to provide dispersal

habitat for spotted owl movement among the large reserves.

Human use of the Augusta area is conditioned to a significant extent by the surrounding landscape. The South Fork corridor is heavily used by anglers, campers, sightseers, and others. This use occurs all along the corridor, of which the Augusta planning area occupies only a small segment. Glimpses of the Augusta area as viewed

from the main road in the corridor, a National Scenic Byway, are part of a larger

pattern of scenery viewed by motorists and bikers. Hiker and horserider use of

ridgeline trail systems in the Augusta planning area also is linked to trailheads and

other trails in nearby areas.

Mammals with large home ranges use the Augusta area as a part of a larger landscape. Cougar (Felis concolor), black bear (Ursus americanus), deer (Odocoileus

spp.), and elk (Cervus elaphus) occur in the Augusta planning area but use significantly larger areas, as well. In particular, the lower slopes of Rebel Ridge and adjacent valley floor landforms are important winter range and rearing areas for elk.

Approach—Before the onset of active fire suppression and intensive timber harvest

in this century, fire had been a major process controlling landscape structure along

the west side of the Oregon Cascade Range for at least 500 years (Agee 1993,

Morrison and Swanson 1990, Teensma 1987). An understanding of the frequency,

severity, and spatial extent of past fire is critical to understanding the historical

distribution of habitats. A fire history of the area was compiled from a field study using

standard dendrochronological techniques (Agee 1993, Morrison and Swanson 1990).

Sample sites for the fire history study were selected from aerial photographs and

clustered along stand age-class boundaries. Both stumps in clearcuts and increment

cores from live trees were used to collect tree and fire-scar ages. Sites with a more

complex age-class structure were sampled more intensively than those with few age

classes or little evidence of fire scars. A total of 1,325 fire scar and tree age records

were used from 1,101 trees sampled on 267 plots.2

Fire episode maps for moderate- to high-severity fires were compiled from the fire

evidence records by generally following procedures described in Morrison and

Swanson (1990). Fire episodes were mapped when the following three conditions

were present:

Phase 1—

Analysis of Past

and Present

Conditions and

Processes

Fire History

2Connelly, K.P.; Kertis, J.A. 1991. Report on Augusta fire history. 49 p.

Administrative report. On file with: Blue River Ranger District, Willamette

National Forest, Blue River, OR 97413.
9

1. At least five sites had scar or tree age dates for that episode.

2. There was a high reliability rating given to the tree age or fire scar data used for

that episode.

3. Sites for that episode were clustered in space as well as time.

Episode boundaries were determined from spatial patterns of fire evidence. A Geographical Information System (GIS) was used to superimpose fire evidence data over

topographic and other resource maps to help discern relations. Episode boundaries

were then manually drawn and digitized into the GIS (see footnote 2).

General fire regime areas were identified and mapped for nine subsections of the

planning area. Each appeared to have a similar stand-age structure and fire history.

Fire regime boundaries generally correlated with areas exhibiting distinctly different

land surface features (i.e., predominant aspect, degree of dissection, elevation, and

slope length). Mean fire return intervals were then calculated for each fire regime

area. Although low-severity fires were not mapped, fire scar records were used to

estimate a rough fire frequency for low-severity fires (see footnote 2).

Results—Twenty-six stand-replacing or partial stand-replacing fire episodes were

dated and mapped (fig. 3). The timing and location of the fire episodes differed

substantially. Most of the area burned in the 1500s (55 percent), but very little burned

in the 1600s (9 percent). Four episodes burned 38 percent of the area in the 1700s,

and the 1800s witnessed an increase in the amount of area burned (57 percent),

possibly due to the influx of Euro-American settlement. Some areas burned multiple

times in the same century, especially in the central part of the planning area in the

1800s. Over the 500 years covered by the analysis, fire episodes ranged from 55 to

3410 hectares (mean, 657 ha [136 to 8,421 acres; mean 1,624 acres]) and differed

greatly in the spatial pattern of the fires. The central portion of the planning area

tended to burn more frequently than the southern portion (fig. 3).

Despite substantial variability, specific disturbance regimes appear to typify certain

parts of the planning area. Through presumed effects on microclimate, fuel loads,

and fire spread processes, topography significantly influenced fire regime. The fireepisode level data were compiled into general descriptions of nine fire regimes based

on the frequency, severity, and patch size distribution of wildfire (fig. 4, tables 2 and 3)

(see footnote 2). For example, fire regime area H (Upper Basins) occurs in upperelevation, north-facing, cirque basins. This area experienced fire infrequently, but the

recorded fires were large and severe. The North Chucksney fire regime (area C)

experienced smaller, less severe, but more frequent fires.

Approach—Fire episode maps were used to create generalized maps of historical

landscape structure. Starting with the earliest fire episode, the sequence of fire

polygons were overlaid in a GIS, and time since the previous fire was tracked for

each grid cell (50 by 50 meters [164 by 164 ft]). Each fire polygon was assumed to

represent a fire of moderate to high severity sufficient to create open-canopy conditions. At 20-year steps, and at the midpoint of each fire episode, maps of open- and

closed-canopy forest were produced. For the purpose of this analysis, open-canopy

conditions were defined to exist for 40 years after a fire. Since 1955, timber harvest

has been the primary mechanism initiating open-canopy forests. Harvest records from

the U.S. Department of Agriculture, Forest Service, were complied to create maps of

open- and closed-canopy forests from 1955 through 1990 (Wallin and others 1996).

Landscape Structure
10

Figure 3—Fire episodes in Augusta Creek, 1530-1973.

Figure 4—Augusta Creek fire regimes.
11

Table 2–Augusta Creek fire regimes

Fire regime area (code) Frequencya Intensityb Sizec

Rebel Ridge (A) Frequent Low-moderate Medium-large

South Fork (B) Infrequent Low Small

North Chucksney (C) Frequent Low-moderate Small

Loon Creek (D) Intermediate Moderate-high Large

Lower Chucksney (E) Frequent Moderate Small

Southwest Chucksney (F) Frequent Low-moderate Medium

Lower Augusta (G) Intermediate Moderate Medium-large

Upper Basins (H) Infrequent Moderate-high Large

Chucksney unroaded (I) Insufficient data

a Infrequent=area characterized by 1 dominant period of burning over the last 500 years.

Intermediate=area characterized by 2 dominant periods of burning over the last 500 years.

Frequent=area characterized by repeated burning throughout much of the last 500 years. b Low=fires generally caused 0- to 35-percent overstory mortality.

Moderate=fires generally caused 35- to 60-percent overstory mortality.

High=fires generally caused >60-percent overstory mortality. c Size refers to the size of the vegetation patches created by fire.

Small=mean patch size <140 hectares.

Medium=mean patch size 140 to 280 hectares.

Large=mean patch size >280 hectares.

Existing forest stands were assigned to a set of stand structure classes. Classes were

defined by the successional stage of the most recent cohort and the level of overstory

retained through the originating disturbance event (table 4). Aerial photographs,

ground data from Forest Service stand exams, and a Willamette National Forest

forest-type map were integrated and validated with field checks and local knowledge.

Although significant portions of the area have been fragmented by clearcutting over

the last 40 years, several large blocks of mature and old forest remain. In other

places, large blocks of young forest have been initiated through forest cutting and

reforestation. We mapped existing large, unfragmented blocks of either young or old

forest from the current stand structure map based on the spatial pattern of existing

stands.

For each map of open- and closed-canopy forest, and for the existing stand structure

map, landscape metrics were generated from FRAGSTATS, software for analysis of

spatial pattern (McGarigal and Marks 1995). We selected edge density (meters per

hectare) and the percentage of closed-canopy forest greater than 100 meters (328 ft)

from an edge with open-canopy forest as ecologically meaningful indicators of landscape structure (Wallin and others 1996).

Results—Historical landscape patterns over the last 500 years consisted of a complex, diverse mix of stand structures and patch sizes differing widely over space and

time. For example, the Upper Basins area contained large patches and a high proportion of older forests. Because of the high fire severity in this area, when younger

forests occurred, they were assumed to generally contain a single cohort. In contrast,
12

Table 3—Hectares of each fire event within each fire regime area, Augusta Creek, 1530 to 1973

Fire regime areaa

Fire date A B C D E F G H I

Year Hectares

1530 51 6 235 140 204 131 656 1530 448

1565 0 0 5 0 0 172 0 39 0

1580 203 34 68 153 200 142 159 81 45

1635 84 15 557 7 26 0000

1730 0 6 427 0 136 2000

1741 2 21 0 29 90 0000

1745 0 0 0 0 0 0 0 291 40

1750 0 0 0 0 0 55 0 135 66

1765 0 2 0 0 80 0 0 0 0

1783 0 20 243 000000

1786 0 0 0 69 00000

1790 153 19 209 117 135 97 221 859 179

1797 0 0 0 0 0 0 132 0 0

1808 249 105 552 103 284 3 78 12 0

1818 0 0 0 0 0 0 0 145 194

1821 0 0 0 13 00000

1830 267 36 254 303 253 61 659 21 0

1843 69 4 0 106 89 0 208 73 6

1852 441 1 173 0 31 0000

1870 0 0 1 165 15 153 72 41 9

1883 173 00000000

1885 0 0 0 15 00000

1894 0 0 0 0 0 181 0 7 0

1897 843 00000000

1920 0 2 120 0 259 428 0 0 0

1973 000700000

 Total 2533 271 2844 1227 1801 1424 2185 3234 986

a Total hectares of each fire regime area: A=1631, B=397, C=900, D=443, E=463, F=569, G=756, H=1822, I=650.
13

the North Chucksney area consisted of complex, multicohort stands generally much

smaller in areal extent due to the smaller, less severe, and more frequent fires in this

area.

Existing landscape structure is primarily the result of stand development patterns from

past fires, with a relatively new overlay of 40 years of dispersed, small clearcuts (fig.

5, table 5). The overall proportions of young and old forests are well within the range

of historical conditions (Wallin and others 1996). However, younger forests in the

existing landscape resulted from clearcutting, not fire, and generally lack the surviving

green trees, snags, and down logs typical of fire-regenerated stands.

Even though the total amount of interior closed-canopy forest has varied by only

about 20 percent over the last 400 years (Wallin and others 1996), patch sizes have

differed greatly. Mean patch size of interior closed-canopy forest has ranged from a

low of about 50 hectares (120 acres) to a high of 320 hectares (790 acres) (fig. 6A).

Relatively small patches of interior closed-canopy forest occurred in the 1500s and

early 1800s in response to extensive fires, and in the last half of the 1900s in response to extensive dispersed-patch clearcutting. A peak in patch size was reached

in the first half of the 1900s, before the onset of timber harvest, owing to a period of

fire absence.

The amount of edge between closed- and open-canopied forests in the landscape

varied over time in response to variation in fire size and frequency (fig. 6B). Edge

densities reached a low point around 1700 due to an extended fire-free period and

then increased in the 1800s in response to a series of fires in the area. Edge densities have steadily increased over the last 40 years to relatively high levels as dispersed patch clearcutting has been implemented (fig. 6B).

Table 4—Stand structure classes used for Augusta Creek analysis

 Overstory retention level

Successional stage of Age of most recent when most recent cohort

most recent cohort cohort was establisheda

Years Percent

Shrub-saplingb 1-20 0, 15, 30, or 50

Closed poleb 21-40 0, 15, 30, or 50

Young 41-80 0, 15, 30, or 50

Mature 81-200 0, 15, 30, or 50

Old >200 na

Meadows na na

Rocks na na

na=not applicable.

a The 0- and 15-percent retention level classes and the 30- and 50-percent retention level classes were

combined to simplify some analyses and displays. b Shrub-sapling and closed pole classes were combined to simplify some analyses and displays.
14

Figure 5—Existing vegetation conditions in Augusta Creek.

Table 5—Area of existing stand structure classes

within the Augusta Creek study area

Stand structure classes Area

Hectares

Early:a

 Light retentionb 1550

 Moderate to heavy retentionc 0

Young:

 Light retentionb 51

 Moderate to heavy retentionc 465

Mature:

 Light retentionb 2100

 Moderate to heavy retentionc 0

Old 2780

Meadows and rocks 688

aEarly=a combination of the shrub-sapling and closed pole classes.

bLight retention=a combination of the 0- and 15-percent retention levels.

cModerate to heavy retention=a combination of the 30- and 50-percent

 retention levels.
15

Although significant portions of the area have been fragmented by clearcutting over

the last 40 years, several large blocks of mature and old forest remain (fig. 7). In

other places, large blocks of young forest have been created through forest cutting

and regrowth (fig. 7). Because large blocks of old forest are difficult to restore once

fragmented and are believed to be critical habitat for some species (FEMAT 1993),

they are considered particularly important landscape elements.

Figure 6—Historical area of (A) interior closed-canopy forest and (B) edge densities in Augusta Creek.

Figure 7—Large blocks of vegetation within the existing landscape.

A. B.
16

Approach—Rain-on-snow events are generally thought to be the major flood producers along the west side of the Cascade Range (Berris and Harr 1987; Coffin and Harr

1992; Harr 1981, 1986). Peak flows were analyzed by assessing the potential of

different parts of the watershed to accumulate and melt snow and store ground water.

Zones of potential snow accumulation were modeled as a simple function of elevation

based on analysis of Soil Conservation Service SnoTel site data.3 Susceptibility of

different parts of the landscape to snowmelt was modeled in a GIS by assigning

highest melt rates to south- and west-facing slopes and to elevations below 900

meters (3,000 ft) (table 6). Melt rates diminished with increasingly northern or eastern

exposures and increasing elevation. Snow accumulation and melt maps were combined with a map of groundwater storage (interpreted from the Soil Resource InvenTable 6—Potential susceptibility to rain-on-snow peak flows within the

Augusta Creek study area

Rain-on-snow

Elevation rangea Aspectsb Soil depthc susceptibility

Meters

<1000 W, SW, S Shallow High

<1000 SE, NW Shallow Moderate

<1000 N, NE, E Shallow Low

<1000 W, SW, S Deep Moderate

<1000 SE, NW Deep Low

<1000 N, NE, E Deep Low

1000-1400 W, SW, S Shallow High

1000-1400 SE, NW Shallow High

1000-1400 N, NE, E Shallow Moderate

1000-1400 W, SW, S Deep High

1000-1400 SE, NW Deep Moderate

1000-1400 N, NE, E Deep Low

>1400 W, SW, S Shallow Moderate

>1400 SE, NW Shallow Moderate

>1400 N, NE, E Shallow Low

>1400 W, SW, S Deep Moderate

>1400 SE, NW Deep Low

>1400 N, NE, E Deep

a Elevation ranges define 3 zones of increasing snow accumulation with increasing elevation. b Aspects were used in combination with elevation zones to define 3 levels of potential snow melt during

rain-on-snow events. c 2 soil depth classes were assumed to correlate with potential ground water storage.

3 Personal communication. 1993. S.A. Ferguson, atmospheric scientist,

Pacific Northwest Research Station, 4043 Roosevelt Way, NE, Seattle, WA

Hydrology
17

4 Legard, H.A.; Meyer, L.C. 1990. Soil resource inventory for the Willamette

National Forest. Eugene, OR: U.S. Department of Agriculture, Forest

Service, Willamette National Forest. [unpaged]. Administrative report. On

file with: Blue River Ranger District, Willamette National Forest, Blue River,

OR 97413.

5 Swanson, F.J.; Grant, G. 1982. Rates of soil erosion by surface and mass

erosion processes in the Willamette National Forest: report prepared for

the Willamette National Forest, Eugene, OR. Corvallis, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 50

p. On file with: Ecosystem Team, USDA Forest Service, Pacific Northwest

Research Station, Forestry Sciences Laboratory, 3200 SW Jefferson Way,

Corvallis, OR 97331.

6 McSwain, M.D. 1993. Report on Augusta watershed analysis. Blue River,

OR: Blue River Ranger District. 29 p. Administrative report. On file with:

Blue River Ranger District, Willamette National Forest, P.O. Box 199, Blue

River, OR 97413.

tory [SRI])4 according to a matrix algorithm (table 6) to produce a map of the potential

susceptibility to peak flows from rain-on-snow events in different portions of the

landscape.

Late season summer baseflow was assumed to be related to locations of late melting

snowpacks, which were modeled as differing by elevation and aspect. Areas lower in

the watershed and with southwest- to southeast-facing aspects were assumed to lose

their seasonal snowpacks first, followed by mid and higher elevation zones and more

north-facing slopes. Snow accumulation, seasonal snowpack melt rate, and groundwater storage were combined to map the estimated contribution to summer base flow

from different parts of the landscape, according to a matrix algorithm (table 7).

Results—The map of potential contribution to rain-on-snow peak flows (fig. 8) is

based on our current understanding of the factors controlling these processes. Data

were not available to validate this map. A key area of uncertainty is the timing of the

contribution from each tributary basin to flood events. The synchronicity of tributary

flows is a critical factor affecting the magnitude and duration of peak flows, which

requires detailed and data-intensive modeling and monitoring to firmly establish. The

rain-on-snow potential map does show, however, two extensive areas of highest risk.

About 23 percent of the area is at relatively high risk of augmenting rain-on-snow

runoff if forest cover were removed. The high risk areas are mid-elevation zones with

a southerly aspect on shallow soils.

The map of potential contribution to summer baseflows (fig. 9) shows areas assumed

to provide water for late-season stream flows. Data were not available to validate this

map. About 19 percent of the area is in a high contribution category. Most of the area

that contributes to late-season baseflows lies in the upper elevation, north-facing

slopes in the unroaded area along Chucksney and Grasshopper Mountains and

adjoining ridgelines.

Approach—Landslide potential maps were created from the existing Willamette

National Forest SRI (see footnote 4). We mapped landslide potential as a function of

soil depth, bedrock type, and slope steepness, as interpreted from the SRI. This map

distinguishes general areas with similar risk of landsliding, based on inventories and

quantitative assessments conducted in nearby areas.5 Each soil type was assigned a

risk rating of low, moderate, or high slide potential.6

Mass Movement
18

Landslide occurrence was mapped from a time series of aerial photographs (1959,

1967, 1979, and 1990) for the Augusta Creek watershed portion of the planning area.

Each landslide was mapped on the photograph in which it first appeared. Landslides

recorded on the 1967, 1979, and 1990 photographs were those that occurred since

the last photograph for that location. The location, size, and initiation type (i.e.,

clearcut, roads, forest) were identified for each landslide in each photographic series

(see footnote 6).

Results—The map of landslide potential interpreted from the Willamette National

Forest SRI shows broad areas in three general categories of risk (fig. 10). About onethird of the area was found to be in a relatively high risk category.

Table 7—Potential contribution to late-season summer baseflows within the

Augusta Creek study area

Contribution to

Elevation rangea Aspectsb Soil depthc summer baseflows

Meters

<1000 SW, S, SE Shallow Low

<1000 E, W Shallow Low

<1000 NW, N, NE Shallow Moderate

<1000 SW, S, SE Deep Low

<1000 E, W Deep Moderate

<1000 NW, N, NE Deep Moderate

1000-1400 SW, S, SE Shallow Low

1000-1400 E, W Shallow Moderate

1000-1400 NW, N, NE Shallow Moderate

1000-1400 SW, S, SE Deep Moderate

1000-1400 E, W Deep Moderate

1000-1400 NW, N, NE Deep High

>1400 SW, S, SE Shallow Low

>1400 E, W Shallow Moderate

>1400 NW, N, NE Shallow High

>1400 SW, S, SE Deep Moderate

>1400 E, W Deep High

>1400 NW, N, NE Deep High

a Elevation ranges define 3 zones of increasing snow accumulation with increasing elevation. b Aspects were used in combination with elevation zones to define 3 levels of potential snow melt during

rain-on-snow events. c 2 soil depth classes were assumed to correlate with potential ground water storage.
19

Figure 8—Potential rain-on-snow peak flow susceptibility.

Figure 9—Potential contribution to summer baseflows.
20

Seventy-three landslides were mapped from the time series of aerial photographs

(fig. 11). Fifteen of these were evident in the 1959 photographs taken before forest

cutting and road construction in the area. Sites of clearcutting and road construction

accounted for an additional 41 landslides from 1967 to 1990; the remaining landslides

occurred in undisturbed forest during the same period.

Most of the observed landslides occurred as small slides dispersed over the watershed. Two large areas of chronic landslides with a high potential for future landslides

also were identified (fig. 11). These areas experienced mass movements before any

road construction or timber harvest had occurred in the Augusta Creek area, and they

continue to move periodically (see footnote 6).

Approach—Riparian forest canopy condition along perennial streams was mapped

by using the same time series of aerial photographs used for the landslide assessment (see footnote 6). For each photo series, the riparian canopy was identified as

either closed or open (Grant 1988). Closed-canopy reaches were further classified as

either deciduous or coniferous, and open-canopy reaches were identified as nonvegetated, vegetated-deciduous, or vegetated-coniferous. Cause of canopy openings

was mapped as clearcut, partial cut, road right-of-way, debris flow runout, streamside

slide, blowdown, fire, or unknown. Each streambank was individually coded.

Riparian forest canopy conditions along intermittent streams were coded as either

open or closed canopy from a GIS overlay of existing vegetative condition (fig. 5) with

the stream network (see footnote 6). Intermittent streams were mapped from aerial

photographs and contour maps and generally placed wherever contour crenulations

occurred.

Stream research in the upper McKenzie River basin has identified the important

ecological roles of large woody debris in streams (Harmon and others 1986,

Lienkaemper and Swanson 1987, Swanson and Lienkaemper 1978). Consequently,

woody debris delivery to streams is a useful index of effectiveness of management

plans to sustain riparian habitat quality. Stream surveys for the mainstem of both

Augusta Creek and South Fork McKenzie River described general amounts and

distributions of wood in stream channels7 (also see footnote 1). For the remainder of

the stream network, relations among riparian forest conditions and large woody debris

in streams were established based on empirical studies in the nearby H.J. Andrews

Experimental Forest (Harmon and others 1986, Lienkaemper and Swanson 1987,

Swanson and Lienkaemper 1978). The existing vegetative condition map was electronically overlain with a riparian area map (defined as one tree height on each side of

all streams for the purpose of this analysis) to yield area of riparian forest capable of

delivering large wood to streams.

The geometry of the stream network influences the array of available habitats and the

potential for postdisturbance recolonization by aquatic and riparian biota of sites

affected by floods, debris flows, or timber cutting. We identified four general types of

small-watershed systems (fig. 12):

Riparian Habitat

and Fauna

7Heller, D.; Baker, C. 1974. An inventory of fisheries and habitat on selected forest streams. Eugene, OR: Willamette National Forest. 215 p.

Administrative report. On file with: Willamette National Forest, Box 10607,

Eugene, OR 97440.
21

Figure 10—Landslide potential as interpreted from the Soil Resource Inventory.

Figure 11—Landslide occurrence over time.
22

1. Highly dendritic, complex networks.

2. Trellis networks.

3. Branched headwaters with long, straight channels downstream.

4. Short side tributaries.

The highly dendritic, complex networks were thought to have a greater range of

habitats and more opportunities for postdisturbance recolonization than the other

systems. The higher number and closer proximity of tributary junctions in these

systems allows movement of organisms from nearby undisturbed streams into

impacted stream reaches (e.g., debris-flows, fires, local flood damage) (Sedell and

others 1990).

Patterns of faunal distribution were compiled from studies in the Augusta Creek

drainage, the South Fork of the McKenzie River, and creeks in neighboring watersheds. For fauna not studied in this area, spatial distributions were estimated from

known habitat associations elsewhere. For several reasons, our primary taxonomic

focus was on fishes and amphibians. First, many stream habitat surveys have been

conducted in this area, and there is a great deal of knowledge of the distributions and

abundances of these aquatic-dependent fauna. Second, aquatic fauna are considered to be well protected by the Riparian Reserves in the Northwest Forest Plan.

Third, amphibians are a diverse taxonomic group, using streams from headwaters to

main-stem channels as well as terrestrial habitats from streamside to ridgelines.

Protection of these aquatic-dependent vertebrates with diverse habitat requirements

could be potential surrogates for other taxa, especially those associated with moisture

and those using both riparian and upland terrestrial habitats.

Figure 12—Stream network in the Augusta Creek project area.
23

Fish distributions in the main stream channels were evaluated from habitat and

distributional surveys over the last two decades. We relied on previous surveys from

Augusta Creek (see footnotes 1 and 7) and from the South Fork McKenzie River8 to

provide basic data for the main stream channels. Previous work conducted in Grasshopper Creek (a tributary of Augusta Creek) and other streams near Augusta Creek

served as a basis for assessing invertebrate and fish distribution and abundance in

response to riparian vegetation patterns and channel morphology (Hawkins and

others 1982, Hawkins and others 1983, Murphy and others 1981, Wilzbach 1985,

Wilzbach and others 1986). Data on ecological processes affecting aquatic fauna also

were available from other nearby basins, including South Fork McKenzie, Horse

Creek, Lookout Creek, Quartz Creek, and North Fork Quartz Creek. Studies examined both individual species or populations, including cutthroat trout (Oncorhynchus

clarki) (Aho 1976; Moore and Gregory 1988a, 1988b; Murphy 1979; Wustenberg

1954; Wyatt 1959), speckled (Rhinichthys occulus) and longnose dace (R. cataractae) (Dodge 1993), and bull trout (Goetz 1994), as well as broader community or

ecosystem responses to disturbances, including management practices (D’Angelo

and others 1995, Gregory and others 1991, Lamberti and Gregory 1989, Lamberti

and others 1991, Moore and Gregory 1989). Many of these surveys have incidental

records of amphibian sitings or have incorporated amphibian data into the fish-based

surveys. These data and known habitat associations for amphibians (e.g., Blaustein

and others 1995, Leonard and others 1993) were used to assess spatial distributions

of amphibians in the basin.

Results—Riparian forest canopy conditions have changed markedly over the period

analyzed, as seen through data generated from aerial photographs (fig. 13). In

general, the trend has been toward more open-canopy conditions over time (from 17

percent open in 1959 to 35 percent open in 1990). The trend differs, however, between lower and higher order streams. Lower order streams (orders 1 and 2) went

from 11 percent open in 1959 to 32 percent open in 1990, primarily the result of

clearcutting, and higher order streams (order 3+) moved from 70 percent open in

1959 to 56 percent open in 1990. Debris flows, streamside slides, and steep, ravelly

slopes adjacent to some higher order streams contributed to open canopy conditions

historically present in some reaches of the larger streams (see footnote 6).

The amounts and distribution of large woody debris in streams differs greatly across

the planning area. About 23 percent of the riparian areas have been harvested for

timber over the last 35 years (table 8) and currently lack large wood sources. About

59 percent of the riparian areas are in mature or old forest (table 8) that could supply

an abundance of large wood in streams, but portions of these areas have been

salvaged for timber products or have had large wood removed from the stream

channel. Much of the large woody debris historically present in the South Fork

McKenzie was salvaged during the 1960s and 1970s. As a result, abundance of large

wood within this section of the South Fork is significantly lower than would be expected in a similar undisturbed stream.

8 Gregory, S.V.; Ashkenas L.R. 1991. Overview of basin surveys, Willamette

National Forest, 1988-1989. Corvallis, OR: Oregon State University. 46 p.

On file with: Blue River Ranger District, Willamette National Forest,

Blue River, OR 97413.
24

Table 8—Existing distribution of stand structure classes in riparian areas within

the Augusta Creek study area

Stream order

Stand structure class 1 2 3 4 5Total

Hectares

Early:

Light retention 410 130 51 48 17 656

Moderate to heavy retention 000000

Young:

Light retention 6 8 0 0 0 14

Moderate to heavy retention 104 43 38 5 14 201

Mature:

Light retention 355 135 87 8 13 598

Moderate to heavy retention 000000

Old 641 225 134 70 32 1102

Meadows and rocks 226 72 8 0 0 306

Totals 1742 613 318 128 76 2877

Figure 13—Open-canopy riparian forest over time in Augusta Creek.
25

The streams of the Augusta Creek study area form a highly dissected network, with

two main-stem fifth- to sixth-order streams (Augusta Creek and South Fork McKenzie

River) and numerous subbasins (fig. 12). Field observations indicated that the stream

map accurately represented the extent of the stream network over the basin as a

whole but slightly underrepresented or overrepresented the true extent of intermittent

streams in some areas.9 Two discrete patterns of stream networks are apparent

between the main stem drainages: (1) the South Fork McKenzie basin is primarily

comprised of subdrainages having multiple first- and second-order headwater

streams flowing into the upper portions of long, straight second- and third-order

reaches lacking tributary junctions; while (2) the Augusta Creek network is much more

dendritic. The Loon Creek basin is an exception to this pattern, exhibiting a strong

trellis pattern with numerous unbranched tributaries draining directly into Loon Creek.

The types of aquatic vertebrates present in the Augusta Creek area differ with stream

size and position within the network. Species composition in Augusta Creek is probably similar to that found in the adjacent portion of the South Fork McKenzie, with

exceptions as noted. The lower portion of Augusta Creek contains both cutthroat and

rainbow trout (O. mykiss) (see footnotes 1 and 7). Cutthroat extend higher in the

drainage than any other fish species and likely occur in all second-order or larger

streams with gradients of less than 15 percent. The adjacent section of South Fork

McKenzie also has bull trout and mountain whitefish (Prosopium williamsoni). Both

species conceivably could use the lower end of Augusta Creek but have not been

observed in those reaches. Before installation of Cougar Dam, both areas also

provided spawning and rearing habitat for chinook salmon (O. tshawytscha) and

potentially could do so again if fish passage around the dam is established.

Nonsalmonid fish species have never been sampled in the Augusta area. It is probable that both speckled and longnose dace are found in the mainstem of Augusta

Creek, up to the Grasshopper Creek confluence. Sculpin species most likely to be

found include Cottus beldingi, C. bairdi, C. confusus and C. rhotheus. Cottus bairdi

and C. rhotheus likely are limited to the lower portion of the drainage, but the other

two species could continue upstream in reaches with gradients less than 5 to 10

percent.

Among all aquatic vertebrates, the Pacific giant salamander (Dicamptodon tenebrosus) is probably the most abundant vertebrate predator in the Augusta drainage in

terms of biomass. It is found in headwater streams above the distribution limits of fish

and comprises 10 to 90 percent of the vertebrate biomass in stream reaches containing trout and other fish species (Hawkins and others 1983, Murphy and others 1981).

It most likely is found in all perennial streams. Additionally, tailed frog (Ascaphus truei)

tadpoles are common in sections of Grasshopper Creek and could be expected in

similar areas.

Although Pacific giant salamanders and tailed frogs are considered stream-dependent species, they have terrestrial life history stages and can be found in upland

habitats. In contrast, Cascade torrent salamanders (Rhyacotriton cascadae) are more

restricted to aquatic habitat. They are found in small streams, seeps, and headwaters

with cool, clear water, below about 1220 meters (4,000 ft) in elevation (Blaustein and

9 Personal communication. 1993. M.D. McSwain, hydrologist, Blue River

Ranger District, Willamette National Forest, P.O. Box 199, Blue River, OR

97413.
26

others 1995) and should occur in the watershed. Several other amphibians are

anticipated to occur within the watershed and may be found along streams, in riparian

zones, and in upland areas.

Approach—A narrative description of general human use patterns from 11,000 B.C.

to 1940 A.D. was prepared from available literature and the archaeological record in

the central western Oregon Cascade Range.10 Willamette National Forest cultural

resource inventory report files, maps, and databases were used to identify archaeological sites within the Augusta Creek area that were found previously through standard field inventories. Potential explanatory features were examined for each of these

archaeological sites and used to construct a probability map of potential undiscovered

sites within the Augusta Creek area. Variables examined included the proximity of

water, meadows, travelways, and topographic features (landforms, elevation, aspect,

and slope). A statistically valid model specific to this planning area could not be built

owing to the low number of known sites (see footnote 10). Modern human uses in the

Augusta Creek area were compiled and mapped by using Willamette National Forest

maps, aerial photographs, and cultural artifact databases.

Results—Human use of the Augusta Creek area has been a longstanding and

significant factor affecting landscape pattern. Human use most likely began about

13,000 years ago with possible visits by Paleoindian populations (see footnote 10).

Little is known about these cultures, but it is believed that small family groups traveled

widely along the west side of the Cascades in search of food and other subsistence

items.

An 1851 map shows the Augusta area to be within the territory of the Santiam band of

the Molala Tribe. Based on very limited Molala ethnographies, the area likely was

used from late spring to fall for hunting and gathering by mobile, family based groups

who wintered in the lower elevation river valleys (Beckman and others 1981).

Initial contacts between aboriginal populations and Euro-American explorers, fur

trappers, and early pioneer settlers occurred in the early 19th century. The latter half

of the 19th century was a time of major cultural change as the Euro-American settlers

displaced native inhabitants. Settlers from the McKenzie River valley and groups from

the Warm Springs Indian Reservation used areas such as Augusta Creek for hunting,

fishing, and huckleberry (Vaccinium spp.) picking. The upper ridges in the Augusta

area support numerous, productive meadows and huckleberry patches and were

regularly used. These meadows were grazed extensively by sheep around the turn of

the 20th century (see footnote 10).

Anecdotal evidence indicates that fire was used by both the Native Americans and

sheepherders (Burke 1979, Coville 1898). Reported and suggested motivations

include meadow and huckleberry maintenance, attracting or herding deer, roasting

grasshoppers, and the sheer delight of watching a fire burn.

Human Uses

10 McAllister, J. 1991. Cultural resource management planning report for the

Augusta integrated resource analysis area. Eugene, OR: U.S. Department

of Agriculture, Forest Service, Willamette National Forest. 22 p. Administrative report. On file with: Blue River Ranger District, Willamette National

Forest, P.O. Box 199, Blue River, OR 97413.
27

The beginning of the 20th century ushered in an era of vigorous fire suppression,

leading to construction of fire lookouts, access trails, and telephone lines within the

Augusta area. Trails generally followed travel routes long established by the Indians

(see footnote 10). The Civilian Conservation Corps built a lookout on Grasshopper

Mountain, trails in the Augusta area, and small dispersed campgrounds along the

South Fork of the McKenzie River during the 1930s.

Human use of the area expanded and intensified considerably in the post-World

War II development era (fig. 14). Roads were built and large-scale forest cutting

began in the 1950s. Recreational use of the area rose concurrently. There are now

trail systems along Rebel Ridge (in the Three Sisters Wilderness), Chucksney Mountain, and Grasshopper Mountain. Dispersed and developed campsites are spread

along the South Fork of the McKenzie River, which is eligible for status as a wild and

scenic river owing to its scenic, recreation, fish, and cultural values. Angling is popular

along the South Fork, and hunting occurs throughout much of the Augusta area. A

road closure in the upper Augusta area during fall is intended to promote a highquality, nonmotorized big-game hunting experience. Other relatively low impact uses,

such as berry picking, mushroom gathering, and beargrass harvesting, occur in

localized areas at various times of the year.

The landscape planning phase followed three general steps:

1. “Special area reserves” allocated in the Willamette National Forest Plan, as

amended by the Northwest Forest Plan, were delineated. We adopted the reserve

boundaries and general management prescriptions in the Northwest Forest Plan

for these areas.

Figure 14—Existing human uses of the Augusta Creek area.

Phase 2—

Landscape Plan
28

2. The remainder of the planning area was subdivided into zones of similar ecological conditions and disturbance regimes. Prescriptions were developed for each

zone based on the interpreted range of historical conditions. These zones were

termed “landscape areas.”

3. “Aquatic reserves” were established to ensure that the full range of objectives in

the Northwest Forest Plan would be met, with particular attention given to the

Aquatic Conservation Strategy (USDA and USDI 1994). These reserves were

based, in part, on the type and intensity of upslope management in the local

landscape area and were designed to reflect general patterns of disturbance

processes.

The resulting set of allocations (fig. 15, table 9) provided the basis for specific landscape prescriptions (table 10). The decisions we made in steps two and three did not

follow the decisionmaking processes required of the Forest Service for such decisions

but were made for the purposes of this case study. We recognize that in actuality

these decisions (e.g., establishing new management allocations) require formal

decisionmaking processes and public involvement before adoption.

Figure 15—Management categories for the Augusta Creek Landscape Plan.
29

Table 9—Management categories for the Augusta Creek Landscape Plan

Management category Area

Hectares

Special area reserves 3351

Aquatic reserves 1311

North Chucksney 1 (100-year rotation, 50% retention) 890

Lower Augusta 2 (200-year rotation, 30% retention) 632

SW Chucksney 3 (200-year rotation, 50% retention) 323

Upper Basins 4 (300-year rotation, 15% retention) 1130

Approach—We adopted the reserve boundaries and general management prescriptions for four special area reserves from the Willamette National Forest Plan, as

amended by the Northwest Forest Plan. Areas with either legislated reserve status

(e.g., the Three Sisters Wilderness), or established reserve status based on the

unique characteristics of the place (e.g., an unroaded area with a trail system and

established use patterns), were assumed to continue in a reserve status. The humanuse analyses were used to determine if historical patterns were accommodated by

these reserve decisions. Guidelines for the frequency of low-severity fires, from either

natural or human ignitions, were established based on information from the fire

history analysis (see footnote 2).

Results—The four special area reserves encompass 3351 hectares (8,281 acres, or

44 percent of the area) and include a portion of the Three Sisters Wilderness, a

corridor along the South Fork of the McKenzie River (a Federal Wild and Scenic

Study River), a special wildlife Elk Habitat Area between the South Fork and the

wilderness, and the Chucksney Mountain Unroaded Recreation Area (fig. 15). Historical human uses and current recreational uses of the planning area are concentrated

within these four places.

Prescriptions for these four areas generally call for natural succession. Low-severity

fires are to be reintroduced on a once-every-100-year cycle in the Three Sisters

Wilderness and Chucksney Mountain Unroaded Recreation Area, where feasible. An

additional related objective is to maintain the extensive dry meadow communities in

the Chucksney Mountain area. For the past 75 years, fire suppression has effectively

removed a primary agent of meadow maintenance, and the areal extent of these

communities is shrinking over time as a result of conifer succession. Until fire can

play a more natural role in the dynamics of these communities, active management

may be required to retard conifer succession.

Approach—The remaining landscape was expected to provide some level of timber

harvest while meeting a variety of additional ecological and social objectives (e.g.,

scenic views, riparian areas, and unique habitats). Four landscape areas were

mapped, each having distinctly different ecological conditions and disturbance

Special Area

Reserves

Landscape Areas
30

Table 10—General objectives for each management category in the Augusta Creek Landscape Plan

Management categories

Upper Lower South Chucksney North Lower Southwest Upper Aquatic

Objective Rebel Rebel Fork Unroaded Chucksney Augusta Chucksney Basins Reserves

General

 vegetation

 management Natural Natural Natural Natural Managed Managed Managed Managed Natural

succession succession succession succession, succession succession succession succession succession

except with timber with timber with timber with timber

maintain harvests harvests harvests harvests

meadows

Desired low-

 severity fire

 frequency Entirearea Not Not Entirearea Entirearea Entirearea Entirearea Entirearea Generally not

burns on applicable applicable burns on burns on burns on burns on burns on desired,but

average of average of average of average of average of average of may be

once every once every once every once every once every once every integrated

100 years 100 years 100 years 200 years 75 years 200 years with adjacent

upslope

treatment

Proportion of

 landscape area

 in managed

 blocks of size:

<40 hectares 80% 20% 100% 20%

40-80 hectares 20% 40% 0% 20%

>80 hectares 0% 40% 0% 60%

 Structural

 stages—

 Density of overstory retained at

the time of

timber harvest 50% 30% 50% 15%

 Stand

 development

 stage—

Shrub and sapling 20% 10% 10% 6.7%

Closed pole 20% 10% 10% 6.7%

Young 40% 20% 20% 13.3%

Mature 20% 60% 60% 40%

Old 0% 0% 0% 33.3%

regimes. The fire regime map (fig. 4) was the primary basis for these delineations. To

draw boundaries around landscape areas, fire regimes D, G, and H were combined,

as were fire regimes C and E.
31

Prescriptions for each of these four landscape areas were drawn from an examination

of the fire history, historical landscape structure, and the watershed process analyses

described in phase 1 (see footnotes 2, 3, and 6, respectively). First, we matched

parameters of timber harvest regimes with corresponding parameters of fire regimes.

Timber harvest rates and rotation ages were linked to the frequency of stand- or

partial stand-replacing fires for each landscape area. The amount of forest cover

retained at the time of regeneration harvest was tied to the perceived severity of

stand- or partial stand-replacing fires in each area. Spatial pattern objectives for each

landscape area were developed from inspection of individual fire event sizes and from

the pattern of patch sizes resulting from recurring fires over time within each area.

The correlation between the desired characteristics of future human-initiated disturbances with past disturbance regimes was general. For example, we tried to reflect the

variability of patch sizes in the historical landscape and the tendency for some parts

of the landscape to have smaller patches than others. The landscape plan calls for a

range of created patch sizes across the landscape, with small patches emphasized in

certain landscape areas and larger patches in others. We assumed, however, that it

would be socially unacceptable to reflect the full range of historical conditions, which

included some very large and intense fires.

Prescriptions were further developed based on results from the stand simulator

ZELIG.PNW (Garman and others 1992, Urban 1993) to provide more details for

silvicultural prescriptions and to evaluate the feasibility of these prescriptions. This

model is capable of simulating stand dynamics over long rotations (200+ years) with

varying levels of overstory retention. Variables considered in the analysis of prescriptions included reforestation composition and density, precommercial thinning density

and residual composition, and commercial thinning timing and density. The ability of

ZELIG.PNW to simulate stand development under previous, standard silvicultural

prescriptions was first demonstrated by comparing model results with the Willamette

National Forest stand projection tables. Sensitivity analyses identified prescriptions

providing sustainable production of wood fiber volume over multiple rotations when

starting with a mature stand.

The hydrologic analyses also were used to evaluate and adjust landscape prescriptions. Prescriptions set for areas of potential high susceptibility to rain-on-snow flood

events or high contribution to late-summer baseflow were adjusted if necessary to

ensure that these hydrologic processes would not be substantially affected by management activities.

General objectives were established for the occurrence of fire. Timber production

objectives and continuation of a fire suppression policy significantly constrain the

ability to maintain the historical roles of fire. Moderate- to high-severity fires were

replaced in this management approach by the use of prescribed fire following timber

harvest activities and by the anticipated occasional escaped fire. Objectives were

established for low-severity fires, through either natural or human ignitions, based on

fire frequency information from the fire history analysis (see footnote 2). The degree

to which these practices simulate the historical roles of fire is largely unknown.
32

Table 11—General silvicultural prescriptions for the Augusta Creek Landscape Plan

Landscape area

Prescription North Lower Southwest Upper

elements Chucksney Augusta Chucksney Basins

Rotation age (years) 100 200 200 300

Retention level

 (% volume retained) 50 30 50 15

Retention mixture (%)a DF–75 DF–85 DF–75 DF–95

WH–20 WH–10 WH–20 WH–3

WRC–5 WRC–5 WRC–5 WRC–2

Reforestation density

 (trees per hectare) 500 750 500 1000

Reforestation mixture

 (%)a DF–40 DF–60 DF–40 DF–75

WH–40 WH–30 WH–40 WH–20

WRC–20 WRC–10 WRC–20 WRC–5

First thinning

 (trees per hectare) 80 at year 12 to 15 80 at year 20 to 25 60 at year 20 to 25 80 at year 12 to 15

Second thinning

 (trees per hectare) 40 at year 35 50 at year 40 50 at year 40 50 at year 40

Third thinning

 (trees per hectare) 20 at year 65 30 at year 70 30 at year 70 30 at year 60

Fourth thinning

 (trees per hectare) Not planned 20 at year 100 20 at year 100 20 at year 100

Low-severity fire (in ad-

 dition to fuel treatments) Not planned Once or twice Twice between Once or twice

between years years 100 and 200 between years

100 and 200 100 and 300

a DF=Douglas-fir; WH=western hemlock; and WRC=western redcedar.
33

This phase of the process was inherently subjective. Integration of the team’s expertise and experience to form cohesive prescriptions required multiple iterations and

active information exchange with many individuals. Numerous field trips by managers

and scientists to the Augusta area and to the nearby Warner Creek fire area helped to

refine concepts.

Results—Four landscape areas were delineated (fig. 15, table 9) that together

occupy about 3000 hectares (7,348 acres, or 39 percent of the planning area).

Prescriptions for timber harvest differed for the four areas (tables 10 and 11). Timber

harvest rotation ages ranged from a low of 100 years (North Chucksney) to a high of

300 years (Upper Basins). Levels of live overstory trees retained at the time of

regeneration harvest spanned a range from 15 percent (Upper Basins) to 50 percent

(North Chucksney and Southwest Chucksney). Guidelines call for patch sizes created

by cutting to range from mostly less than 40 hectares (100 acres; North Chucksney)

to mostly 80 to 120 hectares (200 to 300 acres; Upper Basins).

The silvicultural prescriptions in table 11 were selected for each of the four landscape

areas where timber harvest will occur based, in part, on simulation experiments with

ZELIG.PNW. They have not been field-tested and should be regarded as tentative.

The species mixture to be retained at the time of regeneration harvest differs with the

level of retention. Higher levels of retention are associated with greater proportions of

shade-tolerant species. Similarly, higher proportions of shade-tolerant species are

prescribed in the reforestation mix in landscape areas with higher levels of retention.

Lower densities of planted trees also are prescribed in areas of higher green-tree

retention because of potential overstory-understory competition and higher densities

of natural regeneration. The prescribed timing and density of thinnings differ slightly

based on rotation ages and overstory retention levels.

Review of the hydrologic analyses led to one adjustment in landscape area prescriptions. Because of a potential for increased peak streamflows as the result of timber

cutting activities in the Southwest Chucksney landscape area, desired created patch

sizes were reduced and rotation ages lengthened to minimize the area in opencanopy condition.

Low-severity fires were prescribed when stands reach ages older than 100 years for

all but the North Chucksney area, where the rotation age is 100 years (table 10).

Prescribed fire was delayed until after year 100 to allow for the completion of silvicultural activities prescribed relatively early in the life of a stand, such as commercial

thinning. Also, dominant trees become relatively fire resistant after age 100.

The following sections provide additional details of the landscape plan.

Spatial pattern of retention trees—These guidelines are intended to help translate

spatial objectives for overstory retention from the landscape level to the stand level

and to provide a basis for evaluation of the landscape plan. The intent is to create a

variable pattern of retention trees within landscape blocks. Final placement of retention trees should integrate these criteria and fit on-the-ground conditions assessed at

the time of site-specific timber harvest planning. To the degree allowed by the need to

protect ecological values, spatial patterns of retention trees should use site-specific

disturbance patterns as a general template. Criteria for placement are as follows:
34

• Retention trees should be both clumped and scattered individuals. Clumps should

range in size from 0.1 to 8 hectares (0.25 to 20 acres). Larger blocks should have

larger clumps. Scattered individual trees can range from 40 to 70 percent of the

total retention trees.

• Higher levels of retention should be located near streams and lower slope

positions.

• Retention trees should be placed on sites of potentially unstable ground to the

degree needed to minimize mass movement risks, as determined by on-theground assessment.

• No trees should be cut along any streambank, and trees should not be cut that

directly contribute to streambank stability.

• Rock outcrops, wet areas, or other special or unique habitats needing protection

from harvest and silvicultural activities should be used to anchor retention clumps.

• Spatial patterns should consider the structure and timing of future cutting in

adjacent blocks and minimize edge contrast if feasible.

• Retention trees generally should include the largest, oldest live trees, decadent or

leaning trees, open-grown trees, and hard snags.

• Scattered retention trees generally should be left in the larger tree size classes.

• If on-the-ground conditions indicate that higher levels of retention trees are

needed to meet ecological objectives, prescriptions should be modified accordingly. Similarly, reductions in retention levels may be appropriate in some instances to improve operational feasibility, so long so ecological objectives are

met.

Retention trees are intended to maintain a natural forest pattern and to integrate

upslope and riparian management. Placement of retention trees along edges of

cutting blocks should be designed to (1) minimize edge contrast, (2) avoid sharp

boundaries with high windthrow potential or abrupt microclimate shifts, (3) emulate

common postfire patterns, and (4) maintain nutrient uptake capacity across the

hillslope down to the riparian zone.

Prescribed fire—In keeping with the objective of maintaining ecosystem processes,

we included low-severity fire in landscape prescriptions at approximate mean historic

frequencies. Goals for prescribed fire include:

• Kill a small proportion of overstory trees to create snags and future down wood.

• Reduce fuel loading and fuel ladders.

• Stimulate herb and shrub growth.

• Provide horizontal heterogeneity to understory habitats.

Because the fire history analysis was designed primarily to detect moderate- to highseverity events, these prescriptions should be regarded as first approximations.
35

Low-severity fire was prescribed for some of the reserves (table 10). The intent was to

reintroduce fire where operationally feasible and where there are no unacceptable

risks to other values. Lack of road access may substantially increase costs of treatment and reduce options for fire ignition, holding and mop-up tactics. Low-severity fire

in aquatic reserves would be appropriate for sites where fire has substantially influenced plant communities in the past and no significant risk to ecological processes or

communities exists. Fire also may be appropriate in aquatic reserves to better integrate upslope and riparian habitats.

Low-severity fire also was prescribed in landscape areas where timber harvest is

scheduled (table 11). The timing of prescribed fires differs depending on timber

harvest scheduling. Fire may be prescribed in the near term where mature or old

stands are not scheduled for cutting for several decades. Natural postfire processes

then could occur for several decades before timber harvest. Where timber harvests

occur in the near term, prescribed fire after timber removal can reduce logging slash

where needed and restore fire to the site. As a part of the long-term prescription, lowto moderate-severity fires were prescribed to occur one or two times between age

100 and the timber harvest rotation age (100 to 300 years, depending on landscape

area). Before year 100, fires may cause high levels of mortality to overstory dominants and interfere with early stand silvicultural activities (e.g., precommercial and

commercial thinnings).

Site-specific analysis will be needed to determine locations where fire can be prudently used. Stand conditions, fire history, wind patterns, potential fuel breaks, slope

position, aspect, and elevation all have to be considered. We expect that some areas

will not be suitable for prescribed fire for operational and safety reasons. In areas

where timber management was prescribed, landscape blocks were intended as

operational units and should provide a basis for site-specific planning for prescribed

fire. Where feasible, the upper boundaries of a block were placed along ridgelines or

roads to help establish safe firelines.

Inclusion of areas unsuited for timber harvest—Inclusions of small areas of land

considered “unsuitable for timber harvest” (USDA 1990) occur in blocks where timber

harvest is scheduled. For example, rocky shallow soils and wet areas are scattered

throughout the landscape. In many cases, fires burned through these areas in a

similar fashion as in adjacent forests and have historically been important in shaping

plant community dynamics. Absence of disturbance has resulted in development of

closed-canopy forests in some areas where more open conditions were common in

the past.

Managed disturbances may be appropriate in these areas in conjunction with scheduled timber harvests or prescribed fire. Site-specific analysis should be conducted to

ensure that negative effects on rare species will not occur and that unwanted exotic

species will not invade. Risks at the site level should be balanced against larger scale

goals and conditions. Potential treatments for these areas include prescribed lowseverity fire or felling of trees to open up the canopy and leaving the trees on the

ground. The overall intent is to integrate these areas with surrounding lands and

create natural environmental gradients and conditions similar to those created with

historical disturbance regimes.
36

Response to unplanned disturbances—Changes in future conditions undoubtedly

will occur through unplanned disturbances. Small-scale disturbances (e.g., small

pockets of windthrow, insect-induced mortality, or small fires) create additional

diversity and generally should be viewed as biologically desirable. Changes in the

overall schedule of activities generally would not be necessary, and salvage logging

of these small patches of mortality generally should be avoided.

Large-scale disturbances should trigger reevaluation of landscape objectives and

projected management activities. Even though long-term landscape and watershed

objectives likely still would be applicable, changes in short-term plans may be appropriate. For example, a large, severe fire may produce early seral conditions over a

significant proportion of the planning area. An appropriate response might be to

reschedule timber cutting to delay further regeneration harvests of live forest until the

postfire stands have closed their canopies. Salvage logging of an area of timber

approximately equal to that scheduled to be removed over that period may be appropriate in this instance to maintain the scheduled flow of timber.

Our recommended management response to disturbance depends on current conditions and knowledge and should include consideration of these factors:

• Location of disturbance in the area: If reserves burned, for example, the landscape blocks might need to be reconfigured to provide new reserves; or if fire

occurred in landscape areas where timber harvest was planned, it might be

desirable to redraw blocks to better align block boundaries with new,

postdisturbance edges.

• Timing of disturbance relative to the block schedule: For example, if a fire occurred relatively close in time to a block being scheduled for timber harvest, the

block could be salvaged as a substitute for its scheduled cutting. If timber harvest

is not scheduled for many decades, though, it may be appropriate to leave the

block unsalvaged.

• Extent of disturbance: For example, small areas of blowdown might be considered a biological bonus adding diversity to the landscape. Large areas of

blowdown might trigger a reevaluation of block configuration and scheduling.

• Condition of surrounding watersheds: Burned patches, for example, may serve

particularly important ecological roles if they are the only patches of high snag

densities in the entire watershed.

Ecological functions of dead wood need to be considered if salvage for timber values

is contemplated. Relative to natural conditions, the low levels of snags, and especially

the lack of high-density snag patches, is a key element characterizing managed

landscapes. Leaving mortality patches unsalvaged and maintaining the overall block

harvesting schedule may be the most appropriate response to unplanned disturbance

in many cases.

Approach—Aquatic reserves were established to ensure that aquatic habitats and

processes were protected and that management for aquatic features was integrated

with upslope management. The pattern of aquatic reserves was based on the likely

frequency, intensity, and spatial pattern of future timber harvests; the context of the

surrounding watershed; and the degree to which the landscape has been altered by

Aquatic Reserves
37

past, intensive human use (e.g., dams, roads, timber cutting). The general strategy

followed from our basic assumption that the more the resulting landscape resembled

the historical or “natural” landscape, the higher the likelihood of retaining native

species and ecological functions. We therefore avoided the historically unprecedented, stringerlike patterns created by riparian buffers on every stream and provided

more contiguous reserves that protect entire small watersheds strategically dispersed

across the watershed. Fewer reserves were needed where the Augusta area is

bounded by wilderness, but more were required where the basin is surrounded by

lands heavily impacted by past human uses.

Aquatic reserves are generally comprised of entire small subdrainages (40 to 120

hectares [100 to 300 acres]). They are intended to provide long-term maintenance of

ecosystem function (e.g., flow regimes, water quality, wood delivery, food inputs) and

aquatic biodiversity (e.g., aquatic plants, invertebrates, amphibians, and fish). Species requiring both riparian and upland interior, closed-forest habitat benefit from

these reserves. Reserves also provide potential sources for recolonization of biota

after natural or human-caused disturbances. Recolonization pathways along streams

and over ridgetops are incorporated into the aquatic reserve network.

Aquatic reserves were positioned throughout the landscape to provide a range of

habitat types, topographic settings, and disturbance regimes representative of headwater, middle, and lower portions of the drainage. Their locations incorporated local

topography and drainage patterns to take advantage of areas with high ecological

value and biological diversity. Areas of high stream density with a dendritic aquatic

network of first-order streams and portions of second- and third-order streams were

intended to provide a wide range of aquatic habitats for amphibians, invertebrates,

and fish. Tributary junctions have inherently heterogeneous habitats and diverse

biota,11 and thus were incorporated into reserves. In addition, reserves were established in headwall areas thought to be important for some sensitive species, such as

the Cascade torrent salamander. Steep, unstable areas with a simple drainage

pattern that have potentially long debris-flow runout distances were placed in reserves, as were two areas of chronic mass movement. Protection of these areas

reduces the risks of human disturbances on naturally unstable slopes. This system of

reserves includes habitat for most of the known aquatic species within the basin and

known patches of unique habitat or biota.

Aquatic reserves also took the form of large riparian corridors along both sides of all

major streams. These areas appeared to have maintained older forests through many

past fire events. The corridor reserves were essentially linear and occupy the entire

valley bottom and adjacent toeslopes. These corridors connect aquatic and riparian

areas throughout the basin, link with the small watershed reserves, and include most

fish-bearing streams in the area.

Results—Aquatic reserves (fig. 15) were established in the form of small watersheds

(570 hectares [1,410 acres]; 7.5 percent of the area), chronic mass-movement areas

(164 hectares [405 acres]; 2 percent of the area), and riparian corridors on valley

11Olson, D.H.; Applegarth, J.; Bury, R.B. [and others]. Management

recommendations for survey and manage amphibians in Pacific Northwest

Federal forests. Manuscript in preparation.
38

bottoms along large streams (577 hectares [1,425 acres]; 7.6 percent of the area).

Many of the headwater basins are in the small watershed reserves, which are connected through the large valley-bottom corridors.

General prescriptions for these areas are to allow natural succession and avoid

human-initiated disturbances. Low-severity fires may be prescribed in the smallwatershed reserves to reduce fuel loads and introduce diversity of understory conditions based on site-specific conditions. Fires should be avoided in the chronic massmovement reserves. Low-severity fires may be allowed in portions of the valleybottom reserves if implemented as part of a prescription for adjacent upslope lands.

In phase 3, we developed a spatially and temporally specific portrayal of the landscape plan created in phase 2. Our purposes were to:

1. Test the feasibility of the landscape plan.

2. Provide an explicit basis for evaluation of future landscape conditions.

3. Link landscape objectives to future project-level activities.

We first delineated management blocks, termed “landscape blocks,” in the four

landscape areas where future timber harvest is prescribed; we then used these

blocks as scheduling units to project future landscape conditions.

Approach—Landscape blocks are management units representing the spatial

locations of future vegetation patches created and maintained through timber harvest,

prescribed fire, and other vegetation management activities. The same general ageclass structure will prevail within a block after timber harvest, but the spatial patterning and composition may be quite variable. Objectives for individual landscape areas

provided specific guidance for the range of landscape block sizes and for the spatial

distribution of the blocks. Landscape blocks range in size from 20 to 150 hectares (49

to 370 acres) and may be further subdivided into operational units, such as cutting

units, to implement management activities. Existing stand conditions may be quite

variable within a block and range from very young plantations to old growth.

Landscape blocks were mapped according to the landscape objectives for block sizes

and spatial distribution and the following mapping criteria, listed in order of decreasing priority:

1. Use existing large patches of a similar structural stage wherever possible. Rationale: Large patches with interior forest habitat are the most critical because they

are hardest to establish and maintain.

2. Use ridges and streams for boundaries whenever feasible. Rationale: They are

definable on the ground and are relevant to ecosystem processes and operational

realities.

3. Delineate blocks stream to stream, rather than ridge to ridge, where applicable.

Rationale: Spreads management effects over more than one basin, and increases the stability of riparian reserves by having a mature forest bordering

riparian zones on at least one side.

Landscape Blocks

Phase 3—

Projection

of Future

Conditions
39

4. Use roads as boundaries where feasible, if ridges and streams are not feasible.

Rationale: Roads are definable on the ground and influence habitat conditions

through edge effects.

5. Place smaller blocks in most visually sensitive areas. Rationale: Degree of

perceived change in the landscape is less with smaller blocks.

Results—The map of landscape blocks (fig. 16) depicts a range of block sizes

throughout the planning area. Each of the four landscape areas where timber harvest

is prescribed contains a mix of large and small blocks, although the proportion of

each differs significantly among areas (table 10). The Upper Basins area, for example, is dominated by large blocks with a few small blocks, but the North Chucksney

area contains mostly small blocks with a few larger blocks. This variability and distribution of landscape blocks reflects the general pattern historically expressed across

the landscape.

Approach—Long-term projection of landscape conditions requires a method to

account for forest growth and development and to schedule silvicultural actions. We

adapted and simplified forest planning procedures for long-term analysis. We used

landscape blocks as the basic land units for scheduling timber management actions.

Landscape blocks were scheduled for cutting according to the cutting rate associated

with the rotation age assigned to each landscape area and the following criteria:

Future Landscape

Conditions

Figure 16—Landscape blocks for the Augusta Creek Landscape Plan.
40

• Disperse cutting of landscape blocks so that adjacent blocks are not cut in

consecutive periods. Rationale: Spatial pattern objectives are designed directly

into the landscape block pattern itself.

• Delay cutting in blocks where stream surveys show channel and riparian conditions are in need of recovery (e.g., levels of shade or large wood are currently low

as a result of past cutting or road construction practices). Rationale: Recovery of

stream ecosystem functions will proceed most rapidly in these areas if additional

disturbance is minimized in the short term.

• Schedule initial cuttings in blocks that are currently the most fragmented. Rationale: Retains existing large blocks for the maximum potential time, and establishes

the desired landscape pattern most quickly by creating larger blocks where

fragmented conditions currently exist.

• Delay cutting of a landscape block that is adjacent to blocks containing large

openings. Rationale: Because spatial pattern objectives are designed directly into

the landscape block pattern itself, cutting a block next to existing openings would

create an opening larger than the landscape objectives call for.

• Schedule block harvests so that the mix of block sizes cut in any period is directly

proportional to the desired mix of block sizes within that landscape area. Rationale: Ensures that the desired range of block sizes is present at all times.

We selected 20 years as the length of time in each period for the scheduling analysis.

We assumed that when a timber harvest, prescribed fire, or silvicultural activity is

scheduled to occur in a landscape block, it will be completed within 20 years. Several

factors were considered in selecting 20 years for the period length. Habitat objectives

are generally better met if an entire landscape block is treated within a relatively short

time to minimize the period over which disturbance occurs. Potential problems may

arise, however, if large blocks are cut within a short time. People may judge the visual

appearance unacceptable. Detrimental effects to soil, water, riparian, and fish resources can potentially result when cutting occurs rapidly over a large area. This

concern was partly obviated by the levels of canopy retention planned within landscape blocks (table 10) and the placement of landscape blocks so that they frequently

span multiple drainages and run stream to stream. The exact timing of cutting within

landscape blocks will be determined by individual landscape block at the project level.

The block scheduling was performed by hand. Following the criteria listed above, a

set of blocks was selected for the first period (1995 to 2014 A.D.) and the results

checked against the criteria. Then, a second set of blocks was selected for the

second period (2015 to 2034 A.D.) and checked against the scheduling criteria, and

so on for 20 periods (400 years). The complexity and judgment required to interpret

the four criteria required several modifications and partial iterations to achieve a

satisfactory pattern.

We used GIS to portray long-term landscape conditions. First, the landscape block

map was coded according to the block schedule developed above, so that each

landscape block was assigned a structural stage code for each of the 20 periods.

Then, the existing stand conditions map was given a structural stage code as if it

would grow without further harvest or disturbance (using the structural stage age
41

progression in table 4) for 20 periods. Then, the landscape block map was electronically overlaid with the current stand conditions map. Each resulting current stand and

landscape block combination thus had two sets of attributes for all 20 periods. A

relatively simple if-then algorithm was used to select an attribute for each period from

either the current stand growth series or from the landscape block series, depending

on whether the block had been previously selected for timber harvest. Once the first

cutting for a given block was encountered in the landscape block series, the remainder of the periods were filled in from the landscape block attributes. Stands within

reserves followed the structural stage progression throughout the planning horizon.

Results—Transformation of the current landscape toward the landscape envisioned

in the landscape plan occurs at different rates within different landscape areas. This

differs depending on the degree of past fragmentation and the rate and intensity of

future cutting (fig. 17, table 10). The desired landscape pattern is mostly in place

within 100 years and firmly established by year 200. The projected pattern remains

stable beyond year 200 as stands grow and landscape blocks are reset to early seral

conditions through timber cutting at rates and intensities designed to achieve the

landscape objectives.

No attempt was made to incorporate unplanned disturbances (e.g., windthrow,

wildfire) into our projections. Clearly such events will occur in the future, some

processes with lower frequency than in the natural state (e.g., the results of wildfire

suppression), and perhaps other processes with higher frequency (e.g., increased

windthrow associated with edges of cutting units, debris slides from roads). Analysis

Figure 17—Future landscape conditions under the Augusta Creek Landscape Plan.
42

of these factors is rather speculative and beyond the scope of this paper. It is clear,

however, that such disturbances will interact with the human-engineered landscape

pattern to create more temporal and spatial variability in landscape structure than

projected in this analysis.

The Northwest Forest Plan (USDA and USDI 1994) established a set of land allocations and associated standards and guidelines to direct management activities. In

addition, the Northwest Forest Plan mandates a watershed analysis process that may

be used as a basis for modifying the plan through normal plan amendment procedures. We elected to evaluate the landscape plan described above by comparing it to

the direction in the Northwest Forest Plan, unmodified by any plan amendments

based on watershed analysis. This comparison should provide a reasonable basis to

determine if plan amendments based on the results of watershed analysis would be

desirable in the Augusta Creek area. For purposes of this comparison, we labeled

these two management approaches the “Interim Plan” and the “Landscape Plan.” The

Landscape Plan is described in the previous sections (phases 1 through 3); the next

section presents the key assumptions used for the Interim Plan.

For purposes of comparison, we projected future landscape conditions for the Interim

Plan by using procedures similar to those used for the Landscape Plan.

Prescriptions—General prescriptions were derived from the allocations (fig. 18) and

standards and guidelines in the Willamette National Forest Plan as amended by the

Northwest Forest Plan. Assumptions from the Willamette National Forest timber

harvest scheduling model also were applied. The following specific guidance was

used as a basis for projecting future landscape conditions:

Figure 18—Management areas for the Augusta Creek Interim Plan.

Interim Plan

Phase 4—

Evaluation
43

• Reserves from the Willamette National Forest Plan, as modified by the Northwest

Forest Plan, were applied (fig. 18), except for spotted owl core area reserves. We

did not include the spotted owl reserves in either scenario to prevent disclosure of

owl pair locations.

• Riparian Reserve widths were either one or two tree heights distance from the

stream, depending on stream flow and fish presence. We used a site potential

tree height of 55 meters (180 ft).

• No timber harvest was scheduled within Riparian Reserves.

• Within General Forest management areas, timber harvest was scheduled for an

80-year rotation with 15-percent retention of green trees at the time of regeneration harvest.

• Within Scenic-Partial Retention Middleground management areas, timber harvest

was scheduled for a 140-year rotation with 15-percent retention of green trees at

the time of regeneration harvest.

• Within Scenic-Retention Foreground management areas, timber harvest was

scheduled for a 200-year rotation with 15-percent retention of green trees at the

time of regeneration harvest.

Cutting unit delineation—Conventional approaches to timber harvest unit delineation do not work effectively in this area with the prescriptions in the Northwest Forest

Plan. The combination of the existing landscape pattern, consisting of 2- to 20-

hectare (5- to 50-acre) plantations dispersed over the landscape in both riparian and

Figure 19—Cutting units for the Augusta Creek Interim Plan.
44

upslope areas, and the extensive Riparian Reserve network results in a myriad of

small stands eligible for timber harvest. The topographic setting of many of these

stands makes logging operations difficult. We attempted to redraw future timber

cutting units (fig. 19) with sizes similar to recent practices (2- to 20-hectare [5- to

50-acre] units) by using the following process:

1. We overlaid the existing timber cutting unit map and the stand age map from the

Blue River Ranger District database with the interim Riparian Reserve map.

2. Within the zones between Riparian Reserves, stands with an age difference of

less than 20 years were joined, and stands less than 0.4 hectare (1 acre) were

merged with the most similar adjacent stand.

3. Within the zones between Riparian Reserves, future cutting unit boundaries were

drawn; stand age boundaries were followed where stands were small enough to

be treated as one cutting unit. In larger stands, cutting unit boundaries were

drawn following the existing timber cutting unit map where feasible. Where cutting

unit designations no longer made sense because of Riparian Reserves, cutting

areas were redrawn to correspond with ridgelines and existing roads.

4. Minor adjustments were made in future cutting unit boundaries to yield a more

operationally feasible set of cutting units.

This step is analogous to the landscape block delineation process for the Landscape

Plan, as previously described (phase 3).

Future landscape condition—The future cutting unit map defined the spatial units

used for long-term timber harvest scheduling. The prescriptions provided the rules

governing the frequency and intensity of cutting and the resulting stand structures.

A simple area control method was used to schedule timber harvests over time. In

addition, the following criteria guided the actual selection of individual cutting units for

each 20-year period:

Within general forest management areas—

1. Units designated for cutting were selected first from mature stands, then old, then

young, and last from existing plantations.

2. Cutting units for a given time period were selected from the same zone between

Riparian Reserves where the group of cutting units totaled less than 100 acres,

and 80 percent or more of the group was composed of stand structures from the

same or similar age classes. This rule was applied to minimize fragmentation

created by this prescription. This rule was not applied to the southwest-facing

slopes on Chucksney Ridge owing to concerns over the potential effects of large

openings on peak stream flows.

3. On the southwest-facing slopes of Chucksney Ridge, cutting units were dispersed

over time and space, as feasible.

4. The inter-Riparian Reserve blocks selected for cutting within a period were

dispersed across the larger landscape in succeeding periods to achieve a mix of

stand structures among differing elevations and aspects.
45

Within scenic management areas—

1. Units were selected first from mature stands, then old, then young, and last from

existing plantations.

2. Cutting units were dispersed over time and space, as feasible.

Figure 20 shows the resulting pattern of forest conditions. This step was analogous to

the projection of future conditions step described for the Landscape Plan (phase 3).

Assumptions—To simplify analyses, we made the following assumptions. Road

systems were treated as identical for both scenarios. Fire suppression was assumed

to be 100-percent effective, and other disturbance processes were assumed to not

modify the projected landscape pattern, although we compared the likelihood of this.

Prescribed fire, or other management practices, were assumed to be effective in

maintaining the meadow component of the Augusta landscape. We did not account

for the potential effects of long-term climatic change on our projections of stand

dynamics and timber production over the 400-year planning horizon. Prescribed

practices affecting endangered species require consultation with the U.S. Fish and

Wildlife Service before implementation.

Evaluation factors—We compared the two scenarios by landscape structure (i.e.,

composition, shapes, sizes, and dispersion of different vegetative patches) and

landscape function, specifically streamflows, soil mass-movement processes, habitat

Comparison of

Scenarios

Figure 20—Future landscape conditions under the Augusta Creek Interim Plan.
46

for select taxa (amphibians, fish, birds with special emphasis on northern spotted owl,

and mammals), timber supply, and operational feasibility. Results of this comparison

are summarized in table 12. We included in our analyses those ecological factors that

have been extensively studied within similar watersheds or for which a general

knowledge base exists. We did not consider all species of concern, such as many

taxa on the survey and manage list (USDA and USDI 1994), because of limited

knowledge of the habitat requirements and population demographics of many of

these species. We expect that many of the conclusions we draw would be applicable

to these taxa as well. The comparison of management scenarios is concluded with

consideration of disturbance regimes involving natural processes (fire, wind, insects,

and disease), which may interact with the managed landscape structure, changing

landscape pattern from the intended design.

The forest landscape changes over time in response to timber harvest and the

development of vegetation through structural stages. Stands were modeled as a

function of two characteristics: age and the density of overstory trees retained at the

time of stand regeneration. Total hectares in each structural stage over time are

presented in table 13 for both plans.

Special Area Reserves (44 percent of the planning area) are common to both scenarios. In these reserves, stands progress toward old-forest conditions and are

assumed to remain old forest through the modeling horizon. The remainder of this

section compares conditions in the rest of the planning area.

The Interim Plan develops a distinct, high-contrast landscape composition within the

remaining portion of the planning area (56 percent). Upper slopes within the General

Forest management area (20 percent of the planning area) contain early (1 to 40

years) and young (41 to 80 years) stands with light retention (15 percent of the

overstory). Timber harvest rates based on 80-year rotations truncate the successional

sequence before mature or old stands are allowed to develop. Minor amounts of

mature stands (81 to 200 years) occur in the upper slopes of scenic management

areas close to the South Fork of the McKenzie River (8 percent of the planning area)

where rotation ages are 140 and 200 years. Lower slopes within Riparian Reserves

(27 percent of the planning area) all grow into and remain in the old-growth stage

(>200 years) over time. Forest stands with zero retention levels created during the

last 35 years of clearcut timber harvest eventually disappear from the landscape and

are not replaced in this scenario. The overall landscape is missing the higher retention-level, mixed-age stands found in this area over the past 500 years and develops

a large gap in structural stages as a result of the low amount of mature age class (81

to 200 years; see table 13).

The Landscape Plan develops a more complex and varied landscape composition in

the remaining portion (56 percent) of the planning area (table 13). The portion of the

planning area where timber harvest was prescribed (39 percent) was further subdivided into four Landscape Areas, each developing a different mix of structural stages.

The Upper Basin Landscape Area attains a mix of all age classes in response to a

Landscape

Structure12

12This section prepared by J. Cissel.
47

Table 12—Comparative summary of management prescriptions, patterns, and ecosystem responses of

the Landscape Plan and the Interim Plan, Augusta Creek

Management prescriptions and patterns Interim Plan Landscape Plan

Landscape:

Percent of study area subject to cutting 29 39

Percent of study area managed for

 rotation ages–

 <100 year 20 0

 100-200 years 8 24

 >200 years 0 15

Size range of cutting units (hectares) 2-20 2-120

Riparian reserves No-cut reserves throughout Small watershed reserves in areas of

stream network high biodiversity or landslide hazard

Reserves along major valley bottoms

Some cutting in remaining riparian

areas—integrated with upslope

management

Stand:

Live-tree overstory retention levels

 (% of canopy closure) 15 15-50

Landscape pattern:

Stand edge density

 (% change relative to present condition) +60 -40

Patch size at year 100 (number)–

 <20 hectare 453 137

 >60 hectare 11 24

Hydrology:

Peak flows Little potential for increase Little potential for increase

Low flows Minor decrease in summer No detectable change

low flows

Annual streamflow No detectable difference No detectable difference

Debris slides and flows No detectable difference No detectable difference

Amphibians Aquatic networks and Harvest impacts to species reduced

associated species well by large subdrainage reserve blocks

protected by Riparian and widespread late-successional

Reserve network forest

Upslope habitats at risk for Connectivity maintained between

some species upland areas of interior forest habitat

and streams, favoring terrestrial species

Lower impacts of silvicultural practices

in uplands (higher levels of live-tree

retention)

Greater diversity of riparian habitat
48

Table 12 (continued)

Management prescriptions and patterns Interim Plan Landscape Plan

Fish and selected additional aquatic taxa Aquatic networks and species Long rotations allow significant

well protected by Riparian development of late-successional

Reserve network forest in managed riparian areas

Higher light levels in selected stream

reaches benefit some species

More habitat for broader array of

species

Birds and mammals More early seral habitat, Higher connectivity, within stand structused by 1/3 of bird species; ural complexity, and amount of interior

more edge habitat mature and old-growth habitat potentially increase persistence, refugia, dispersal, and colonization potential of

some species, particularly those associated with late-successional forests

Northern spotted owl:

Territory habitat (number of the present

 10 activity centers subject to partial or

 complete habitat loss) 5 1

Competitive interactions with Greater competitive interactions

 other species with edge species—barred

and great horned owls

Dispersal habitat (hectares meeting 6030 6678

 11-40 after 40 years) Better habitat and lower risk of

negative competitive interactions with

other species

Timber yield (long-term average annual):

Cubic feet +16% Larger, higher value trees to market

Board feet +6%

Operability Lower complexity of planning Greater flexibility in prescribing

and implementing harvest site ecological objectives and

operations; difficult access to and harvest operations

numerous, small cutting units

heavily dissected by Riparian Prescriptions require more intensive

Reserves timber sale planning and layout

Disturbances that can alter landscape

 prescription:

Fire Lower potential for spread under

extreme conditions; greater ability to

predict spread

Windthrow Lower windthrow potential at stand

edges, including riparian zones

Insects and disease More of landscape in stand

conditions with lower densities

of endemic insects
49

Table 13—Area of stand structure classes over time for the Landscape Plan and Interim Plan,

Augusta Creek

Time from present

Stand structure class Existing Year Year Year Year Year Year Year Year Year Year

20 40 60 80 100 120 160 200 300 400

Hectares

Interim plan

Early:a

Light retentionb 1550 1529 925 922 913 914 926 915 925 924 916

Moderate to heavy retentionc 00000000000

Young:d

Light retentionb 51 520 1510 1370 925 922 913 926 915 915 924

Moderate to heavy retentionc 465 444 0 0 0 0 0 0 0 0 0

Mature:e

Light retentionb 2100 1969 1890 2249 1129 1183 1193 1168 291 291 291

Moderate to heavy retentionc 0 0 391 338 310 310 310 0 0 0 0

Oldf 2780 2486 2230 2067 3669 3617 3605 3937 4815 4815 4815

Meadows and rocks 688 688 688 688 688 688 688 688 688 688 688

Landscape Plan

Early:a

Light retentionb 1549 1109 159 154 171 143 83 192 160 154 143

Moderate to heavy retentionc 0 199 484 571 535 529 537 527 486 529 486

Young:d

Light retentionb 50 508 1366 913 159 154 171 83 192 160 154

Moderate to heavy retentionc 461 426 0 199 484 571 535 537 527 571 527

Mature:e

Light retentionb 2104 2018 1961 2231 1222 1090 1152 1168 412 447 446

Moderate to heavy retentionc 0 0 416 404 368 540 624 487 678 692 779

Oldf 2779 2684 2559 2472 4006 3918 3842 3950 4488 4391 4409

Meadows and rocks 688 688 688 688 688 688 688 688 688 688 688

a Early=1 to 40 years since establishment of the most recent cohort. b Light retention=0- to 25-percent retention of overstory at time of establishment of the most recent cohort. c Moderate to heavy retention=26- to 50-percent retention of overstory at time of establishment of the most recent cohort. d Young=41 to 80 years since establishment of the most recent cohort. e Mature=81 to 200 years since establishment of the most recent cohort. f Old=greater than 200 years since establishment of the most recent cohort.
50

very long rotation age (300 years). Young stands have a relatively low level of overstory (15 percent). The other three Landscape Areas subject to timber harvest contain

all age classes except old, in response to moderate or long rotations (100 or 200

years), with 30- or 50-percent overstory retention levels. Aquatic Reserves (17 percent of the planning area) provide blocks of old forest intermingled with areas managed for timber removal. Forest stands with zero retention levels created from the last

35 years of timber harvest eventually disappear from the landscape and are not

replaced in this scenario. The mix of rotation ages and retention levels prescribed for

different Landscape Areas results in substantial amounts of all structural stages and

more closely resembles the landscape composition of the previous 500 years. Although it takes many decades for these conditions to be fully expressed in the landscape, differences between the two scenarios are evident at the close of the first

period (year 20).

Distribution of structural stages across slope positions differs markedly. In the Interim

Plan, old forests are confined to riparian areas and lower slope positions. Old and

mature forests are not allowed to develop in middle and upper slope positions because of the relatively short rotation age of the Interim Plan. Similarly, young forests

in riparian areas and lower slope positions phase out of the landscape in the Interim

Plan because Riparian Reserves are designated along all streams. The Landscape

Plan distributes a wider range of structural stages across all slope positions. Long

rotations and moderate to high levels of canopy retention allow development of

mature and old forests within harvested areas. Low- to moderate-intensity cutting

would occur within some riparian areas and lower slope positions at a low frequency

in the Landscape Plan.

The Interim Plan leads to a more fragmented future landscape than either existing

conditions or the Landscape Plan. Differences in the distribution of patch sizes

between the two plans are striking (table 14). Frequent cutting due to relatively short

rotations and generally narrow areas where cutting occurs between Riparian Reserves result in an increasing number of small patches in the Interim Plan. Conversely, the number of small patches gradually decreases over time in the Landscape

Plan as cutting occurs in larger blocks and at lower frequencies. Larger patch size

classes, especially the 60- to 400-hectare (150- to 1,000-acre) class, show the

opposite trend. Patches of this size decrease from 17 to 3 in the Interim Plan and

increase from 17 to 24 in the Landscape Plan. Mature and old-forest patches in the

Interim Plan are found in either the relatively narrow, linear Riparian Reserve network

or in the larger Special Area Reserves. The Landscape Plan provides large patches

of mature and old forest distributed across the landscape.

The amount of edge between forest and open areas also differs significantly between

the two plans (fig. 21). The Interim Plan results in a 60-percent increase in edge

compared to existing conditions, primarily as a result of cutting units in upslope

positions bordering old forests in Riparian Reserves. This relatively abrupt transition

from riparian areas and lower slopes to upper slopes introduces artificial gradients in

environmental conditions, such as light, temperature, soil moisture, and wind penetration (Chen and others 1995a). Plant communities and mortality rates may be affected

by abrupt edges (Chen and others 1995a). The Landscape Plan decreases the

amount of edge in the landscape by almost 40 percent relative to existing conditions.
51

Table 14—Comparison of patch density by patch size class for the Landscape

Plan and Interim Plan, Augusta Creek

Number of patches

<10 10-19 20-59 60-400 400+

Time from present by plan hectares hectares hectares hectares hectares

Existing

 Interim Plan: 121 30 22 17 2

 Year 20 188 45 34 18 2

 Year 40 273 49 30 15 2

 Year 60 343 55 36 18 2

 Year 80 383 62 37 10 1

 Year 100 389 64 36 10 1

 Year 120 389 63 42 9 1

 Year 160 346 55 40 8 1

 Year 200 237 49 31 3 1

 Year 300 239 49 31 3 1

 Year 400 243 45 34 3 1

Landscape Plan:

 Year 20 142 49 35 17 2

 Year 40 123 30 25 24 2

 Year 60 130 39 33 22 2

 Year 80 112 27 23 20 2

 Year 100 114 23 24 22 2

 Year 120 115 27 24 22 2

 Year 160 91 19 23 24 2

 Year 200 43 9 22 21 1

 Year 300 44 11 20 22 1

 Year 400 44 10 21 21 1
52

Long rotations reduce the rate of change in forest conditions over time, and moderate

to high levels of overstory retention reduce contrasts between cutting units and

adjacent stands.

Land-use activities that change the volume of water accumulating within a landscape

or the rate at which water travels through the landscape can alter the hydrology of a

watershed. Changes can occur in the total annual or seasonal streamflow or in the

magnitude or timing of peak (flood) or low flows. Such hydrologic effects are of

concern because they determine the availability and movement of water on hillslopes

and in channels. The amount and movement of water, in turn, can trigger landslides,

debris flows, and channel changes, which affect aquatic or riparian habitat. Here we

consider the effects of the Interim Plan and the Landscape Plan on hydrologic processes based largely on studies in nearby watersheds (e.g., Harr 1981, Jones and

Grant 1996).

Factors considered in evaluating the hydrologic effects of the two scenarios included

the (1) size of landscape blocks, (2) within-block treatments (i.e., density of residual

stands), and (3) location of blocks within the watershed. Key aspects of the block

distribution included their location with respect to rain-on-snow zones (defined by

elevation and aspect), streams, and subwatersheds. Their relation to roads was not

considered, because roads were considered similar in the two scenarios. Roads,

however, seem to have significant effects on peak flows (Jones and Grant 1996,

Wemple 1994, Wemple and others 1996).

Figure 21—Comparison of edge density for the Augusta Creek Landscape Plan and Interim Plan.

Hydrology13

13This section prepared by G. Grant.
53

A qualitative analysis of the relative effects of the two management scenarios was

conducted for peak flows, low flows, and average annual streamflow. The Augusta

watershed does not have gauges, so quantitative analysis was not feasible. From a

hydrologic standpoint, the key difference between scenarios is the area of open

canopy having relatively low evapotranspiration and higher potential for rain-on-snow

increases in peak flows (Harr 1981). In this discussion, open vegetation conditions

are those with shrubs or saplings at less than 50-percent retention or pole stands at

less than 30-percent retention plus all open meadows or rock areas.

Effects on peak flows—Principal concerns in examining effects of forest management on peak flows include extent and geographic pattern of areas of open vegetation conditions where snow may accumulate to greater depths and melt more rapidly

than in forested areas (Harr 1981). The contrasting patterns of cutting units and old

forest that emerge under the Interim Plan will result in considerable spatial heterogeneity in rates of water accumulation and runoff during either rain-on-snow or spring

snowmelt events. Consequently, there is little likelihood for synchronous runoff from

different parts of the basin with resulting increases in major peak flows. The greatest

effects on peak flows are likely to be experienced by the small, north-facing subwatersheds draining into the South Fork McKenzie River. If the scale of cutting unit

approaches the size of the individual subwatersheds, a high proportion of trees in the

watershed may be cut at one time. Under these conditions, higher fall and winter

peak flows may result; peak flow increases may be as great as 20 to 50 percent,

depending on the type of storm and antecedent conditions (Jones and Grant 1996).

Consequences for channel habitat, however, are likely to be minor, because these

north-facing drainages are quite steep and boulder-dominated and can absorb

increased flows without significant channel adjustments.

Under the Landscape Plan, there is also considerable heterogeneity of landscape

pattern at the scale of the Augusta Creek analysis area. Consequently, both snow

accumulation and melt rates will be quite varied over the basin as a whole, resulting

in little tendency for synchronization of runoff from different landscape elements.

Overall, there is likely to be little potential for further increase in peak flows, particularly for larger channels, under either scenario. The existing road system may generate increased peak flows that will persist into the planning period.

Effects on low flows—Late summer low streamflow, which influences streamwater

temperature and extent of aquatic habitat, is evaluated in terms of likely leaf area of

hardwood and conifer vegetation in riparian zones. Early successional hardwood

stands in riparian zones, especially red alder (Alnus rubra Bong.), have high potential

to remove water from flood-plain groundwater systems, thereby reducing summer low

flows (Hicks and others 1991). Conifers, on the other hand, have much lower rates of

transpiration during hot, dry summer periods and, therefore, have less potential to

draw down summer low flows.

Under both plans, summer low flows may decrease slightly in the next few decades in

response to increased evapotranspiration associated with growth of upland vegetation in clearcuts and riparian hardwoods. The magnitude of these effects is difficult to

predict, however, and may be strongly conditioned by any major floods that occur

within this time frame that could disturb riparian zones and reset succession. One
54

direct consequence of lower late-summer flows may be slightly elevated stream

temperatures; this would be offset, however, by development of fully shaded riparian

zones through time.

The high degree of spatial heterogeneity in block size, treatment, and location under

the Landscape Plan minimizes effects on low flows. Stream temperatures may be

somewhat more elevated in parts of the landscape as a result of reduced canopy

cover in the very limited area subject to cutting in riparian zones. This effect, however,

probably will be undetectable in the mainstem channel.

Effects on total annual streamflows—Effects of management practices on total

annual streamflow were considered in terms of altered evapotranspiration in response

to vegetation change, which would appear mainly in late spring and summer low flows.

Under both scenarios and at the scale of the entire watershed, there may be a small

decrease in total annual streamflow relative to the current condition within the first 20

years, due to regrowth of trees in uplands and riparian zones. About 29 percent of the

Augusta Creek area currently is in open stand conditions. In the Interim Plan, the area

of open stand conditions declines to 21 percent within 20 years as trees mature,

primarily in Riparian Reserves, and remains essentially constant thereafter. Because

evapotranspiration (ET) is about 20 percent of the total water budget (Rothacher and

others 1967), an 8-percent decrease in area in open vegetation conditions may

decrease water yields by less than 2 percent (the ET component is recovered in an

additional 8 percent of the area). This magnitude of stream flow change is undetectable with standard gauging techniques.

In summary, the extent and intensity of cutting treatment under the two scenarios

differ little in their effects on streamflow at the scale of Augusta Creek. Individual

subwatersheds may experience altered peak, low, and annual flows when cutting is

concentrated in them, but such conditions are limited in time and space.

Vegetation disturbance, such as wildfire and logging, and the presence of roads can

increase the frequency and magnitude of soil movements by debris slides (small,

shallow, rapid movements of soil down steep hillslopes) (Sidle and others 1985,

Swanson and Dyrness 1975). Analysis of debris slide inventory data from areas near

Augusta Creek and elsewhere in the Pacific Northwest indicates that clearcuts and

road rights-of-way experience higher frequencies of debris slides than forested areas

(Marion 1981, Morrison 1975; also see footnote 5). The sliding rate for clearcut areas

may be increased for about 20 years postcutting owing to changed water balance and

loss of rooting strength on unstable slopes. No analysis of effects of partial cuts has

been conducted in the Douglas-fir region because partial cutting has been limited in

extent and, where done, has occurred on gentle slopes.

There seems to be little difference in debris slide hazard between the two scenarios.

The primary areas of concern (roads and known areas of unstable soils) are treated

similarly in both scenarios. The greater area subject to cutting in the Landscape Plan

(39 percent compared to 29 percent of area subject to cutting in the Interim Plan) may

create more cutting-related sliding. This effect may be offset, however, by the longer

Debris Slides and

Flows14

14This section prepared by F. Swanson.
55

rotation lengths and higher levels of retention in the Landscape Plan, which would

result in less area in a state of high debris-slide hazard at any particular time. The

Interim Plan, for example, would result in 37 percent more area cut per year, and this

would be at 15-percent retention compared with 15- to 50-percent retention in the

case of the Landscape Plan (table 12).

Debris flows (rapid movements of soil, sediment, and organic debris down stream

channels) are infrequent in the Augusta Creek landscape, and most are triggered by

debris slides from hillslopes. Hence, the above analysis would apply as well to debris

flows, so we expect the two scenarios to be similar in likelihood of debris flow occurrence.

In summary, the potential for debris movements in hillslopes or in channels is similar

between the two scenarios because of similarities in extent of roads, cutting, and

avoidance of slope stability problem areas.

Three broad assemblages of Pacific Northwest amphibians in forested landscapes

are distinguished by habitat preference: (1) terrestrial species—roughly a third of the

Pacific Northwest forest amphibians occur only in riparian and upland forest; (2)

stream species—about another third have life history stages that require flowing

water (seeps, headwater tributaries, first- through fifth-order streams); and

(3) pond-breeding species—about a third require still water (ponds, lakes, slow

portions of streams) for reproduction. Some stream and most pond-breeding species

have complex life histories involving multiple habitat types. Although linear Riparian

Reserves may protect the rearing habitat of aquatic-breeding amphibians, upslope

habitats may be important for dispersal, foraging, and winter refuge of terrestrial

forms (e.g., tailed frogs, Pacific giant salamanders, Northwestern salamanders

[Ambystoma gracile], and red-legged frogs [Rana aurora aurora]). Consequently,

forest management plans that maintain connectivity of critical combinations of habitat

types can better assure persistence of these species.

The qualitative assessment of the two scenarios with regard to forest amphibian

habitats and populations focuses on parts of the Augusta basin where forest cutting is

prescribed. This is both the area where the plans differ significantly and the area of

highest expected amphibian diversity. Upper elevation reserves (e.g., Three Sisters

Wilderness and Chucksney unroaded area) are expected to have fewer amphibian

species because of habitat constraints, including climate.

Key amphibian taxa are evaluated and the scenarios compared by habitat and population persistence. Habitat considerations include habitat quality, patch size and

shape distributions, connectivity, and refuges for planned and unplanned disturbances.

Habitat—The main benefit for amphibians in the Interim Plan is the direct habitat

protection offered to the aquatic and riparian life-history forms by the Riparian Reserves. These buffer zones adjacent to aquatic habitats are expected to offer extensive protection of the most critical habitats required by all life history stages of about a

quarter of the 27 forest-dwelling species in the Pacific Northwest. Forest cutting plans

in the Interim Plan are anticipated, however, to put amphibians using upland habitats

at risk, including members of the terrestrial, stream, and pond-breeding assemblages.

Amphibians in upland forests are generally ground-dwellers that use surface debris

Amphibians15

15This section prepared by D. Olson.
56

as refuges during active seasons and retreat to these refuges or farther subsurface

during inactive seasons. Disturbance of soil, litter, woody debris, and rocks by tree

felling and yarding and by piling and burning of slash can destroy microhabitats.

Retention of a small portion of live trees and downed woody material may do relatively little to offset upland disturbances to soil surface and subsurface microhabitats.

In addition to these immediate, direct effects, inputs of large, downed woody material,

necessary for the creation of microhabitats for many amphibian species, would be

quite limited over the long term in the 80-year rotation prescribed for the Interim Plan.

The Interim Plan substantially changes the microclimate of logged upland sites. The

80-year rotation and 15-percent retention can produce xeric conditions that few forest

amphibians may tolerate (Blaustein and others 1995). Development of a shrub layer

and canopy closure should ameliorate the harshest microclimate conditions, but

species associated with old-growth forest conditions, in particular, may not remain in

upland areas repeatedly cycling through unsuitable temperature and moisture regimes. Alteration of microclimates in Riparian Reserves also may be detrimental to

amphibians. Chen and others (1995a) observed microclimatic effects of sharp forest

edges extending from an opening to more than 240 meters (790 ft) into the adjacent

forest. Such an edge effect could potentially reach all the way to the stream. Altered

temperature and moisture regimes in riparian zones may reduce the distribution and

abundance of terrestrial- and aquatic-dependent amphibians known to be associated

with “interior” old-growth conditions (Blaustein and others 1995). A shift in the microclimate of Riparian Reserves also may affect amphibian habitat by accelerating decay

of surface litter and wood (Chen and others 1995b).

The Landscape Plan provides several mechanisms for retaining and renewing the

upland microhabitats required by amphibians. First, aquatic reserve blocks include

contiguous riparian and upland habitats. Old-growth habitat will develop and persist in

these reserves, offering refuges to protect entire life cycles of amphibian species,

both aquatic and terrestrial. Second, the long intervals between timber harvests

(rotation lengths up to 300 years) allow old-forest conditions to develop in upland

areas and be sustained across much of the watershed. Such long rotations allow

accumulation of large downed wood and bark piles, necessary habitat components

for some amphibian species. Third, the greater retention levels (up to 50 percent)

provide habitat and reduce the severity of microclimate changes postharvest.

A large proportion of the harvestable riparian and upland areas of the Landscape Plan

is expected to have suitable microclimate for amphibians, thus providing connectivity

across all important habitat types and landscape positions. Interior forest microclimate

conditions can persist in the large reserves and landscape blocks with long rotations

(fig. 17). The Landscape Plan should provide better source areas from which recolonization may occur across the watershed after planned or unplanned disturbances.

Population persistence—Amphibian persistence in the Interim Plan should be

highest for aquatic-dependent amphibians. Persistence of the terrestrial amphibian

assemblage is at higher risk in the Interim Plan. Populations may become fragmented

by the unit sizes of upland forest blocks and the frequency and intensity of harvest.

Riparian Reserves may function as source areas for recolonization of upland habitats.
57

Several features of the harvestable part of the Landscape Plan lead to greater

probability of persistence of amphibians. The larger block sizes of the Landscape

Plan, the fewer impacts to habitats and microclimate conditions within blocks where

logging takes place, the broader distribution of refuges in riparian and upland areas,

and the greater connectivity result in greater potential for persistence. All amphibian

life history stages and assemblages gain substantial protection in the Landscape

Plan. Old-growth forest conditions from streams to ridgelines allow for dispersal of

amphibians among watersheds.

In summary, the Landscape Plan was designed in part to specifically meet habitat

needs of amphibians ranging from aquatic to uplands. Therefore, this plan is rated as

superior in terms of providing better habitat and greater likelihood of persistence of

species using uplands habitats.

Forest management can directly affect aquatic communities of streams in steep

terrain, such as the Augusta Creek area. Fish are useful indicators of environmental

and ecological change because they (1) have the longest life spans of most aquatic

organisms, (2) occupy higher trophic levels and integrate responses of lower trophic

levels, (3) have strict habitat requirements, and (4) are species of interest to humans.

Fish species occupy third-order and larger streams in the Augusta Creek watershed

and locally occur in second-order streams draining into larger streams (fig. 12).

Headwater streams not containing fish are important to fish-bearing streams for

maintaining input of cold water with low levels of suspended sediment and supplying

food for fish, their prey, and other elements of native aquatic communities.

Critical points for comparison of the scenarios are habitat structure, refuges from

disturbances, and light levels reaching the stream as they may affect primary production, water temperature, and foraging efficiency.

Habitat—The Interim Plan provides a high degree of protection for existing riparian

areas along intermittent and perennial streams throughout the Augusta Creek analysis area. The high density of intermittent, first-order, and second-order streams within

the basin creates a dense network of Riparian Reserves. This Riparian Reserve

system gives a high level of protection to sources of wood delivery to streams,

canopy cover, and streambanks and provides intact corridors across the full stream

network from the confluence of Augusta Creek and the South Fork of the McKenzie

River to the ridgeline reserves.

The Landscape Plan provides for similar levels of protection for riparian areas along

larger, fish-bearing streams and along many of the smaller streams throughout the

Augusta Creek area. Old-growth corridors would not occupy all streams within each

subbasin at all times in the Landscape Plan. Partial harvest planned in riparian zones

along small streams would locally reduce the potential sources of wood delivery,

canopy cover, and streambank protection.

In general, in-stream habitat for fish would be protected or restored in the Landscape

Plan, but openings along smaller streams could create warmer conditions in patches

within the harvested areas. Thermal effects would be of short duration because of

Fish and Selected

Aquatic Taxa16

16This section prepared by S. Gregory and L. Ashkenas.
58

vegetation regrowth, and no warming of the mainstem stream is expected because

of the wide Riparian Reserves along fish-bearing streams. With continuation of firesuppression policies, several species of concern (USDA and USDI 1994: table C3)—

e.g., algae-grazers such as Fluminicola sp., Juga sp., Helisoma sp., Lanx patelloides,

and Ascaphus trueii larvae—may benefit from higher light levels resulting from local,

temporary open-forest conditions created by limited cutting in riparian areas under the

Landscape Plan. Plants that require higher inputs of solar radiation also may benefit

(e.g., aquatic lichen [Hydrothyria venosa]).

Large woody debris is a critical habitat feature for many aquatic species. Under the

Landscape Plan, loading of large woody debris in nonfish-bearing streams would be

lower than the level expected in old-growth systems as a result of partial cutting in

adjacent riparian zones. When we consider all fish-bearing streams within the basin,

the Interim Plan is expected to deliver slightly more large woody debris to streams;

but some of this delivery may come from unnatural concentrations of blowdown at the

abrupt edges of Riparian Reserves. Management activities could compensate for

these differences through designed delivery of wood to streams.

The scenarios offer equal levels of protection for critical refuges for fish, including

flood plains and secondary channels along larger channels. Hydrologic analysis

suggests little difference between the two scenarios. However, analysis of effects of

past cutting and roads in other basins in the Willamette National Forest suggests that

peak flows may be increased substantially in areas on 80-year rotations with the road

networks traditionally used to support forest management (Jones and Grant 1996).

This effect of earlier practices common to both future scenarios could result in

greater disturbance and episodic mortality to stream fauna than would be expected

in unmanaged basins.

Population persistence—Aquatic species, including trout and other fish species,

would benefit from the water quality, in-stream habitat, and riparian habitat quality

provided by the full Riparian Reserve system of the Interim Plan; however, abundances of native populations may decline somewhat from reduced food production

and feeding efficiency in shaded reaches. Studies of trout populations within this

drainage have demonstrated that food abundance is generally greater in stream

reaches with canopy openings, because higher light levels result in greater food

production and feeding efficiency (Murphy and others 1981, Wilzbach and others

1986). The cool stream temperatures fostered by the full Riparian Reserve system of

the Interim Plan would benefit bull trout, which is particularly dependent on cold water

conditions.

Trout populations and other fish species would not be adversely affected by the

Landscape Plan, but conditions differ in some minor respects from the Interim Plan.

The higher light levels along the limited extent of stream reaches where some logging

occurs in riparian zones may lead to higher fish production in response to greater

food production and feeding efficiency. Wind and wildfire historically created canopy

openings along streams; wind may be an increased factor in the Interim Plan because

of increased susceptibility of trees along edges of Riparian Reserves.

In summary, long-term persistence of fish communities within the Augusta Creek

planning area is predicted to be similar between the two plans. Aquatic species that

benefit from higher light levels would be locally favored by the Landscape Plan where

partial harvest occurs in riparian areas.
59

Most of the birds and mammals in the Augusta area are forest-dwelling, closedcanopy species with relatively small home ranges. Only 13 of the 53 indigenous

species of mammals in the Augusta Creek watershed are associated with early seral

stages, and 7 species demonstrate a strong preference for late-successional conditions. The other species are either habitat generalists or riparian dependent, or they

require closed-canopy forests. Based on the habitat assessment by McGarigal and

McComb (1993), more than half of the bird and mammal species are associated with

some type of coarse woody debris. Home-range size for about half of the species is

less than 4 hectares (10 acres). Wide-ranging species, such as elk and cougar, have

home ranges crossing multiple drainages within the study area. About a third of the

99 indigenous species of birds use early seral habitat. The remaining 66 percent of

the species are closed-canopy species or are associated with streams. The northern

spotted owl is the primary old-growth associate. Most (87 percent) of the bird species

have a minimum home range of less than 5 hectares (12 acres).

Habitat—In the Interim Plan, the portion of the landscape managed on an 80-year

rotation with 15-percent overstory retention will never develop old-forest structures

and, thus, is unlikely to function as habitat for late-successional species. These sites

will provide habitat for early seral species, however.

The Landscape Plan will provide more habitat for most species because of the

greater range and maximum level of green-tree retention and amount of older,

structurally diverse forests. The high-retention areas in the Landscape Plan probably

will function as old-forest habitat at ages 50 to 80 years postharvest for some species.

The Landscape Plan offers greater amounts and more widely dispersed nesting and

denning habitat for species using large trees (e.g, pileated woodpecker [Dryocopus

pileatus]) or logs (e.g., American marten [Martes americana]).

Habitat conditions within riparian areas are functionally similar between scenarios.

Species that feed extensively in streams but nest in forests would find similar quality

of nesting habitat in the two plans. Stream-associated species, such as the American

dipper (Cinclus mexicanus), spotted sandpiper (Actitis macrularia), and mink (Mustela

vison), would be little affected by the minor differences in vegetative pattern between

scenarios.

Landscape patterns in harvestable areas differ substantially between scenarios and

provide different benefits to mammals and bird species. The larger block design of the

Landscape Plan provides more suitable habitat for species associated with latesuccessional forests or with interior habitat of older forests. For species with small

home ranges, these larger blocks buffer against the displacement of populations due

to the loss of suitable habitat by disturbance events. That is, loss of pieces of habitat

within the larger block could have little effect on the connectivity of suitable habitat or

the interior conditions of the forest. This is in contrast to smaller habitat patches in

which degradation of even small portions may render the patch unsuitable and force

individuals to disperse. The Interim Plan lacks large blocks except in the high-elevation reserves, which are common to both scenarios.

Birds and Mammals17

17This section prepared by S. Garman and M. Hunter.
60

The amount of edge between grass-forb-shrubs and closed-canopy forested habitats

is greater in the Interim Plan. Edge species, such as elk, black-tailed deer (Odocoileus hemionus), great-horned owl (Bubo virginianus), and olive-sided flycatcher (Contopus borealis), will be favored by the Interim Plan. Accompanying these benefits are

potential detrimental effects. The potential for displacing northern spotted owls is higher

because of the negative interactions with barred (Strix varia) and great-horned owls.

The larger number of small patches of early seral habitat in the Interim Plan decreases habitat availability for species requiring large patches of habitat. For example, the American kestrel (Falco sparverius) requires relatively large openings

(greater than 12 hectares [30 acres]) in proximity to its cavity nest. Most early seral

habitat produced in the Landscape Plan is of sufficient size and configuration for this

species; whereas the small, early seral patches produced in the Interim Plan have

less potential as habitat for this species.

Connectivity among old forest features differs greatly between the two plans. In the

Interim Plan, connectivity through the landscape is provided only by the Riparian

Reserve network. In the Landscape Plan, connectivity among old-forest blocks is

provided by Aquatic Reserves along large streams linking larger blocks of mature and

old forest. In addition, areas with long rotations (200 to 300 years) have a significant

portion of the area in mature or old forest distributed throughout the area at all times.

For example, in the Upper Basins where there is a very long rotation (300 years),

species requiring mature or old forest for dispersal will have a 100- to 200-year

window for dispersal. Landscape areas with 30- to 50-percent overstory retention

have a significant component of large trees over the whole area at all times. For

example, the North Chucksney Landscape Area will have 100-year rotations but

relatively high amounts of large woody debris and high overstory retention (50 percent). Species requiring large woody debris for dispersal will find most of this entire

slope suitable over most of the planning period.

Connectivity of early seral habitat differs between scenarios. The open-canopy, early

seral habitat in the Interim Plan is maintained in relatively numerous, small, scattered

patches. In the Landscape Plan, this habitat is distributed in fewer but larger blocks.

Many of the mammal species primarily associated with early seral habitats seem to

have the ability to disperse through closed-canopy forests, as many are occasionally

observed or captured in forests (e.g., pocket gophers [Thomomys spp.] and meadow

voles [Microtus spp.]). Most early seral bird species can disperse through forests and

simply fly over forested areas to reach suitable habitat. The Interim Plan may be more

favorable for early seral species with low-dispersal capabilities compared to the

Landscape Plan.

Concerning refuge from major disturbances, the two scenarios share some protection

of habitat by virtue of the large area of nearby wilderness. The larger block design of

the Landscape Plan provides a greater buffer against loss of habitat from catastrophic

disturbance events for species requiring habitat patches ranging from 160 to 1010

hectares (400 to 2,500 acres) (fig. 17). The more numerous, smaller patches in the

area subject to cutting in the Interim Plan present greater potential for habitat loss for

species dependent on large patches (table 14).
61

Population persistence—Long-term persistence of mammal species over the study

area potentially will differ little between scenarios. However, areas in the Interim Plan

experiencing repeated harvest with low levels of retention may result in the localized

extinction of low-mobility species requiring overstory cover (e.g., red-tree vole [Phenacomys longicaudus]). The higher levels of retention and longer rotations of the

Landscape Plan provide greater opportunity for species to persist on harvested sites.

Doyle (1990) found riparian zones in a nearby watershed to function as source habitat

for a variety of small mammals. The extent of Riparian Reserves in each scenario

should provide adequate levels of source habitat for these species.

A more detailed analysis was conducted based on use of a bird-habitat association

model that takes into account patch size and patch interior requirements. This analysis revealed that habitat for early seral species is greatly limited in both scenarios.

Habitat availability for these species averages about 5 percent of the planning area

over much of the 400-year planning period as a result of the emphasis on older

forests and smaller sizes of early seral patches. Long-term persistence for these

species depends on their ability to colonize newly created habitat patches. Most early

seral species indigenous to the study area are common on intensively managed,

privately owned forest lands northwest of Augusta Creek. Additional early seral

habitat is expected to be produced by unplanned fire and wind disturbances that were

not factored into the bird-habitat model assessment.

Persistence of bird species associated with late-successional forests is potentially

enhanced in the Landscape Plan owing to the larger amount and patch sizes of

suitable habitat. For instance, predicted habitat availability for late-successional

species, such as the pileated woodpecker, is about 20 percent greater over much of

the planning period compared to the Interim Plan.

In summary, the Interim Plan provides more edge and early seral habitat of benefit to

some birds and mammals; but overall, the Landscape Plan provides more habitat for

the broader array of species because of the greater range and broader distribution of

habitat conditions (tables 12 and 13).

Extent of late-successional forest habitat is positively associated with northern

spotted owl site occupancy (Ripple and others 1991, Thomas and others 1990, USDI

1992). The effects of forest fragmentation on spotted owl survival and reproduction

are unclear, however, but are generally hypothesized to be detrimental (Thomas and

others 1990, USDI 1992). Some possible detrimental effects are changes in microclimate (Chen and others 1995a) that may affect thermoregulation of owls, improved

conditions for spotted owl competitors and predators (Johnson 1992), and reduced

dispersal opportunities. Although exact prescriptions for dispersal habitat are unknown, it has been hypothesized that forested stands meeting or exceeding “11-40”

criteria (i.e., stands having >40-percent canopy cover of trees at least 28 centimeters

[11 in] d.b.h.) are conducive to the dispersal of juvenile spotted owls (Thomas and

others 1990). Critical points for comparison of the scenarios are live tree retention

levels, number and arrangement of large patches of late-successional forest, amount

and type of stand edge, and amount of habitat meeting 11-40 criteria.

Northern Spotted

Owls18

18This section prepared by K. Swindle.
62

Although northern spotted owls have been extensively studied, attempts such as

these to predict how they might respond to specific, hypothetical landscapes are

highly speculative.

Habitat—Forests most often selected by northern spotted owls in this area occur

below 1600 meters (5,000 ft) in elevation and exhibit a high degree of structural

complexity, such as multilayered, multispecies canopies dominated by large overstory

trees with moderate to high canopy closure and a high incidence of standing and

downed woody debris. Portions of the Augusta Creek study area contribute little to the

habitat needs of spotted owls, including portions of the Chucksney Unroaded Area

and the Three Sisters Wilderness which are above 1600 meters (5,000 ft). Most of the

area, however, is comprised of forests that provide suitable to optimum habitat for

dispersing and resident northern spotted owls.

A limited number of surveys in the Augusta Creek study area over the past decade

have identified activity centers (defined as an area about 40 hectares [100 acres])

of concentrated activity of either a pair of spotted owls or a territorial single owl) of

10 pairs of northern spotted owls. This is likely to be close to the total territorial owl

population for the entire area, and for purposes of this comparison, is assumed to be

the entire population. Recent surveys indicate that one of the owl activity centers

appears to have dissipated. A second owl activity center appears to be unstable since

1992, and a third seems to be marginal (i.e., not holding a territorial pair for consecutive years). All three of these sites have experienced timber harvest in or close to their

activity centers during the past decade; harvest was most extensive near the site

abandoned by owls. The remaining seven activity centers have been occupied for

numerous years and are considered stable.

Two of the 10 owl activity centers fall within the special area reserves common to both

scenarios. Successional development after year 200 may create habitat for one to

two additional pairs in these reserves. Under the Interim Plan, the remaining eight

pairs are likely to be impacted in the first several decades by timber harvest within

their home ranges (defined as the total area used by a pair of spotted owls for hunting, nesting, and roosting; about 400+ hectares [1,000+ acres]). Five pairs will

experience partial or complete loss of their activity centers. Under the Landscape

Plan, four pairs would experience loss of habitat within their home ranges, and one

would experience partial or complete loss of its activity center in this same period.

Population persistence—The area managed for wood production in the Interim Plan

is less favorable for both dispersing and resident northern spotted owls due to (1)

rapid and permanent loss of large patches of late-successional forest, (2) increase in

edge density and high edge-contrast which favor predators, and (3) less area meeting

11-40 criteria for dispersal. The Interim Plan quickly degrades the harvestable portions of the study area as a landscape through which owls could disperse to and from

neighboring Late-Successional Reserves and in which several pairs may reside and

reproduce ephemerally over the next several centuries. In contrast, the Landscape

Plan better maintains current owl habitat over the next several decades and centuries. In the case of either scenario, decisions and actions tailored to meet the needs

of owls in specific activity centers may reduce impacts on owls. The Landscape Plan,

however, offers managers greater flexibility to positively affect northern spotted owls

in areas managed for timber production.
63

In summary, for northern spotted owls, the Landscape Plan provides significantly

better habitat and lower risk of negative competitive interactions with other species.

In addition, if activity centers had been considered when aquatic reserves were

mapped, the Landscape Plan could have offered additional protection for these

centers by providing larger core area reserves than those mandated by the Northwest

Forest Plan.

Simulations used to develop and test prescriptions (described above in phase 2) also

were used to calculate average, per hectare, long-term yields of merchantable timber

volume. All volumes expected to be produced by intermediate and regeneration

harvests over an entire rotation were summed and divided by the rotation length to

produce an average annual yield. Simulated average annual yields of timber volume

for each silvicultural treatment were multiplied by the respective area and summed to

obtain a long-term average yield for each scenario (table 15). The Landscape Plan

produces about 16 percent less timber volume (cubic feet) than the Interim Plan. This

difference narrows to just 6 percent in terms of board feet, because the Landscape

Plan produces bigger trees under the longer rotations.

The differences in timber production would narrow still further if the 40-hectare (100-

acre) spotted owl activity center reserves mandated by the Northwest Forest Plan had

been taken into account when aquatic reserves were delineated in the Landscape

Plan. Neither scenario incorporated these reserves to protect the specific locations

Timber Production

and Operational

Feasibility19

19This section prepared by S. Garman and J. Mayo.

Table 15—Comparison of area by long-term timber yield categories for the

Landscape Plan and Interim Plan, Augusta Creek

Long-term yield category by plan Area

Hectares

Interim Plan:

 1990 plan reserves 3351

 Riparian Reserves 2070

 80-year rotation at 15% retention 1559

 140-year rotation at 15% retention 537

 200-year rotation at 15% retention 109

Landscape Plan:

 1990 plan reserves 3351

 Aquatic Reserves 1311

 100-year rotation at 50% retention 890

 200-year rotation at 30% retention 632

 200-year rotation at 50% retention 323

 300-year rotation at 15% retention 1130
64

from disclosure. In the Landscape Plan, however, these reserves could overlap the

small watershed reserves and not further reduce timber yields. In the Interim Plan,

these reserves would reduce the area available for cutting to a greater extent.

Results of our projection of multiple rotations of treatments with high levels of greentree retention indicate a slight decrease in the dominance of Douglas-fir, starting with

the second rotation. This is due to the increased shading by residual stems, which

inhibits establishment of Douglas-fir, but in turn promotes the development of shadetolerant species, such as western hemlock and to a lesser extent, western redcedar.

This decrease in dominance of Douglas-fir is not as apparent in the silvicultural

prescriptions of the Interim Plan. These results should be viewed as highly speculative, however, because empirical data are not available to corroborate model predictions under the combinations of retention level and rotation ages used in these

scenarios.

The operational feasibility of timber removal differs between the two scenarios

because of the greater complexity of silvicultural prescriptions in the Landscape Plan.

Given the higher levels of retention and the need to pay more attention to the dispersion of retained stems within a harvest block, the Landscape Plan may require a

greater effort to plan harvests and mark trees for removal or retention. Different and

probably more intensive tracking protocols also are required in the Landscape Plan to

ensure compliance with the prescriptions. The biggest change in operational procedures will be to accomplish the retention levels and spacing of cutting units across the

landscape. Even though silvicultural prescriptions are simpler in the Interim Plan, this

plan will be challenging to implement in terms of gaining access to the numerous,

small cutting units between Riparian Reserves. Either plan will require new and

innovative methods of extraction and likely increase harvest costs as compared to

traditional practices.

Road management may present more options in the Landscape Plan because the

longer rotation and bigger blocks will result in short periods of high use interspersed

with long intervals of low activity. This means that many roads would have to be open

for only short periods.

Collectively, more complex prescriptions of the Landscape Plan will result in higher

costs for planning and implementing harvest of less extracted timber. This may result

in reduced revenues, but this will depend on trends in the timber market. Increasing

value of older, larger volume trees grown in the Landscape Plan may offset the higher

costs. Also, greater opportunity for harvesting special forest products from older forest

in the Landscape Plan may partially offset the potential reduction in timber revenue.

In summary, slightly lower timber volume yield projected for the Landscape Plan may

be offset by higher economic returns in wood quality from the long-rotation stands

and harvest of other forest products. Both plans present operational difficulties that

will require creative management approaches.

Future, unplanned wildfire will affect landscape pattern. Even with active fire suppression, the Willamette National Forest has experienced an average of 470 hectares

(1,165 acres) burned per year from 1960 to 1995 when there has been significant

Wildfire20

20This section prepared by S. Swetland and F. Swanson.
65

road access for suppression efforts. This averages 5 hectares (13 acres) per year for

an area the size of the Augusta study area; the only actual reported fire in the study

area during this period totaled 55 hectares (136 acres) in 1973 (see footnote 2). For

reference, from 1497 to 1850, the Augusta area experienced about 34 hectares (84

acres) of burning per year (see footnote 2). This indicates that fire suppression is less

than 100 percent effective. If we assume that the Augusta area is representative of

the Willamette National Forest, in the past 35 years the study area burned at a rate of

15 percent of the rate in the presuppression period represented by dendrochronologic

analysis.

Arrangement of stands across the landscape differ between the two scenarios in

ways that affect fire risk and behavior. The fragmented and lower canopy density of

managed stands in the Interim Plan would leave stands more exposed to wind, which

allows increased drying of fuels and, thus, more rapid rates of spread and more heat

release per unit area in the event of fire. In normal periods of high fire danger, spatial

variation in fuel type presents opportunities to control fires. The small size of blocks

and arrangement upslope and downslope of cut and leave blocks in the Interim Plan

may not allow space or time for this strategy. During periods of high fire danger, fire in

the fragmented, smaller blocks of this plan could spot from one upslope harvest area

to another or run along fingers of cut or reserve stands. Although the less fragmented

landscape in the Landscape Plan may offer conditions for a larger, continuous fuel

bed and potentially larger fire, suppression strategies are more easily determined.

Fire-behavior prediction models are based on single fuel models with a continuous

fire front. More complicated arrangements reduce accuracy of predictions.

In summary, wildfire can be anticipated in the Augusta area under any likely future

management scenario. The Interim Plan is likely to present higher potential for spread

under extreme conditions, and fire managers are likely to have lower ability to predict

spread.

Windthrow in the Cascade Range can significantly alter the intended pattern of

managed stands across a landscape and the intended functions of landscape pattern.

Several windthrow effects of the two management plans can be considered, but

interpretations based on past experience and research must be tempered by differences between past and prospective management systems. Most past windthrow

studies focused on the extent of wind effects at forest-clearcut edges in upland areas

(Gratkowski 1956, Sinton 1996). This type of windthrow alters the intended landscape

management pattern. However, the types of edges that existed under the past

dispersed clearcutting system may not be duplicated in either management plan

considered here. A second concern is windthrow of riparian buffer strips, which has

been investigated (Sherwood 1993, Steinblums and others 1984) in the central

Oregon Cascade Range area for much narrower riparian strips than those prescribed

in the Northwest Forest Plan. A third windthrow effect is toppling of live trees retained

in cutting units. Knowledge of extent of this type of blowdown is limited by the short

period of use of this practice. In a preliminary study, Adler (1994) examined 44 cutting

units harvested 1 to 10 years previously in the central Willamette National Forest.

Windthrow21

21This section prepared by F. Swanson.
66

Retention levels ranged from 0.8 to 8 trees per hectare (2 to 20 trees per acre). From

0 to 58 percent (mean = 15.6 percent) of retained live trees had blown down, and an

additional 16 percent died standing. Using a simulation model and assuming retained

trees became windfirm after 5 years, Adler estimated that 25 to 75 percent of trees

would be blown down after 10 years.

In terms of edge-related blowdown, we believe that the edge characterization typed

by degree of contrast between adjacent stands and by edge density (fig. 21) is a

useful representation of relative susceptibility to windthrow of landscapes under the

two scenarios. Edge density under the Landscape Plan is within the range of variability for the past 500 years (fig. 6). Edge density under the Interim Plan is 150 percent

higher than in the Landscape Plan after 80 years of implementation (fig. 21).

Windthrow of riparian zones also is likely to be higher in the Interim Plan. Higher

density of Riparian Reserves, shorter rotation lengths and lower levels of green-tree

retention in stands adjacent to riparian reserves, and potentially more abrupt stand

edges under the Interim Plan result in more extensive areas of high windthrow

susceptibility.

We currently lack ability to evaluate the relative consequences of the two management plans in terms of blowdown of dispersed, retained, live trees in cutting units. To

make such an assessment, it is necessary to know effects of density of retained trees

and cutting frequency on windthrow susceptibility.

In summary, we expect that the Landscape Plan would result in substantially less

windthrow along stand edges and that higher levels of standing trees in cutting units

would remain as compared to the Interim Plan.

Insects and pathogens of trees are ecologically important disturbance agents, drivers

of nutrient cycling, and regulators of productivity in both positive and negative senses

(Perry 1994; Schowalter 1995a, 1995b). Here we focus on their roles in limiting tree

survival and growth.

The susceptibility of individual trees or stands to damage by insects or disease, or

both, is a result of environmental factors, such as climate, light, mechanical injury,

windthrow, slash, and fire. These factors often occur in various combinations, thereby

increasing susceptibility. A weakened tree is more prone to disease, which in turn

makes it less resistant to attack by insects. Insects are present at all times but usually

are kept in check by environmental conditions and predators.

The two plans differ little in terms of risk of insect and disease damage. However,

stand characteristics distinctive to each plan could, in the event of an outbreak, result

in different rates of spread and levels of damage.

Under the Interim Plan, 75 percent of the managed area will be on an 80-year rotation

with 15-percent retention. Thinning entries in these areas can maintain stand health

and vigor of the understory, and the low retention level will minimize damage to the

residual stand. The low number of residual trees will be at a high risk for windthrow,

22This section prepared by J. Mayo.

Insects and

Diseases22
67

but the small amount will not provide enough habitat for an outbreak of insects. As

stand conditions change, endemic levels of insects could gradually increase in the 25

percent of the managed area on a 200-year rotation.

In the Landscape Plan, about 30 percent of the managed area will be on a short

rotation (100 years) but with 50-percent retention of the overstory. With this amount of

retention, more damage to the residual trees is likely, and slash treatment will be

more difficult, thereby resulting in increased fire risk. Thinnings scheduled in the

understory will help to maintain vigor and allow the necessary adjustments in stand

composition to keep the risk of insect damage at a minimum. The remaining managed

area (200- to 300-year rotations) may experience increased competition between the

overstory and understory as the stand develops for more than a century after the last

scheduled thinning. Endemic levels of insects may increase gradually as the understory matures and slows in growth.

In summary, the Landscape Plan would have more area in stand conditions with

higher endemic populations of insects. This would not result in a significantly higher

risk for the Augusta analysis area as a whole because of the relatively small area

where the differences occur.

The Landscape Plan developed in phase 2, and integrated into a spatially and

temporally specific landscape pattern in phase 3, lays the groundwork for an efficient

project-level planning process. Larger landscape- and watershed-scale issues have

been addressed and reconciled as best our collective judgment allowed. The context

and Landscape Plan provided by this analysis can focus project-level planning for

timber sales, prescribed fire, silvicultural activities, and restoration or recovery

projects.

Within the four landscape areas where timber harvest was prescribed, the next logical

step is to develop specific prescriptions for management activities at the scale of the

individual landscape block. Landscape blocks delineate areas where silvicultural

activities and fire may be prescribed to create future stands of a similar structural

stage (fig. 16). The type and timing of future activities can be established by comparing existing conditions within a block to projected future conditions. Detailed prescriptions for individual landscape blocks provide the context and direction for locating

project unit boundaries and specifying contract language. Landscape block prescriptions should include the specific levels and patterns of canopy retention within the

block, the potential use of fire, dead wood levels and distribution, treatment of areas

not managed for timber production, logging systems, and the timing of activities within

the block. For example, landscape block number 33 (65 hectares [160 acres]; fig. 16)

is in a landscape area where the Landscape Plan calls for a timber harvest to establish a new cohort in the first 20 years with a general retention level of 30 percent. The

landscape block prescription might include the following guidance:

1. Mature forest in this block should be cut early in the 20-year period. Rationale:

Will better create a block of similar structure because existing plantations in the

block are less than 10 years old.

2. Cutting should occur at the same general time within the block. Rationale: Will

minimize the time during which disturbance is occurring.

Links to

Project-Scale

Planning
68

3. Retention level of mature forest cutting should average 40 percent. Rationale:

There are already 18 hectares (44 acres) of plantations in the block with no

retention of older trees.

4. Retention trees should be distributed throughout the block but concentrated near

the intermittent streams on the south and north boundaries of the block. Rationale: This pattern closely resembles historical disturbance patterns and will help

shade and stabilize the streams.

5. A mix of shade-intolerant and shade-tolerant species be planted according to the

density of green-tree retention within the local area. Rationale: More shadetolerant species will survive and grow better in localized areas of higher retention

tree density.

6. Block should be harvested in three different cutting units to minimize ground

disturbance. Rationale: This configuration allows for efficient use of logging

systems while minimizing ground disturbance.

7. Prescribed fire should be used in conjunction with the harvest activities. Rationale: Fire will help stimulate early successional herbs and shrubs and reduce fuel

loadings.

8. Low-intensity prescribed fire should be allowed to burn into areas having soils

unsuited for timber harvest. Rationale: Integrating the disturbance over the entire

block creates more natural environmental gradients and creates dead wood

habitat.

Silvicultural activities and prescribed fire may be appropriate in the near-term in

blocks scheduled for regeneration harvests in later decades. For example, precommercial and commercial thinning prescriptions can be based on the projected

trajectory of conditions for the corresponding landscape block. The timing of major

cutting and regeneration efforts for the block as a whole can help determine thinning

prescriptions (e.g., stocking levels, spatial patterns within stands, timing of entries).

Thinning prescriptions for a 30-year-old plantation, for example, would likely differ

depending on whether the block were scheduled for regeneration harvest 20 to 40

years from now or 120 to 140 years from now. Prescribed fire may be most appropriate in the short term in blocks dominated by mature or older forests scheduled for

regeneration harvest in later periods. This approach avoids high levels of mortality

that might result if younger stands were burned and allows natural postfire processes

to occur for several decades before timber harvest.

Fire, primarily through natural ignitions, was prescribed in two of the special area

reserves. Followup analysis will be necessary to identify the conditions and zones

where fires may safely burn. Active management efforts were called for to maintain

the high-elevation meadow component in the Chucksney Unroaded Recreation Area.

Succession to conifers and continued fire suppression threatens the existence of the

extensive meadows in this area. Analysis of historical conditions revealed the extent

and rate of meadow loss. These results indicate the need to develop projects that will

either maintain existing meadows or create new meadows.

Watershed recovery and restoration projects also can be identified and focused

based on the results of this analysis. Information on historical disturbance regimes

affecting stream channels can be combined with stream survey data to identify the
69

locations and types of restoration activities likely to be effective. For example, historical aerial photographs showed areas that were chronic sources of mass failures

before road development and clearcutting in the area. Other areas experienced

roadside failures in more recent times. Rehabilitating the roadside failures may be

more effective than placing woody debris in streams subject to periodic debris-flows.

Other examples could include road decommissioning in areas with high contribution

to rain-on-snow events or summer baseflows, or silvicultural activities in relatively

stable riparian zones currently deficient in large wood to accelerate conifer regeneration and growth.

The level of detail in the landscape prescriptions reflects the level of accuracy and

precision in the data and analysis, and provides flexibility to make project-level

decisions fit the larger scale context and at the same time work well with specific

onsite conditions. We purposefully left many choices for project-level planning, such

as the size and level of riparian buffer for many streams. This flexibility also reflects a

degree of trust that land managers have the skills and on-the-ground expertise to

integrate ecological conditions and objectives into practical prescriptions. Without

such flexibility, the complexity and diversity of on-the-ground conditions cannot be

adequately considered, and any resulting standardized prescriptions likely will fall

short of meeting ecological and social objectives. This flexibility needs to be balanced

by active monitoring programs to ensure that local decisions are consistent with larger

scale objectives and plans.

The approach we have described provides an example of a spatially and temporally

explicit landscape plan for ecosystem management. Our objectives were to maintain

native species, ecosystem processes and structures, and ecosystem productivity over

the long-term in a federally managed landscape where substantial acreage was

allocated to timber harvest. The landscape management approach we have described

demonstrates:

• Use of historical disturbance regimes to develop future vegetation management

regimes: In portions of the landscape where timber harvest was allocated, rotation lengths, harvest rates, green-tree retention levels, the spatial pattern of

timber harvests, and prescriptions for fire were based on past fire frequencies,

intensities, and spatial patterns.

• An integration of terrestrial and aquatic management objectives and prescriptions:

Landscape objectives and prescriptions were established based on aquatic and

terrestrial habitat information. Aquatic reserves were designed to complement

upslope management patterns given both the larger landscape prescriptions and

local conditions. An intent of this approach was to provide many habitats (e.g.,

spotted owl dispersal habitat) across the entire landscape.

• A linkage of objectives across scales: The management approach was set in a

regional- and National Forest-scale context, and it links to project-level activities

by establishing temporally and spatially specific objectives and prescriptions.

The projected trajectory of conditions for individual landscape blocks provides

guidance for the type and timing of appropriate management activities at individual sites.

Discussion

Key Elements of

This Approach
70

At this time, we can make only a conjecture about the value of this approach. It

appears, however, to offer several advantages when compared to the Interim Plan

(table 12). Larger patch sizes with greater interior habitat, less edge between open

and closed canopy forests, greater diversity of stand structures, and better distribution of habitats across the landscape provide numerous advantages to many species.

Species having both aquatic and terrestrial life history stages (e.g., Pacific giant

salamanders) would benefit from the more integrated and connected landscape in

this approach. Other species (e.g., American marten), whose habitat would be found

predominantly in high-edge Riparian Reserve stringers in the Interim Plan, would

benefit from having habitat more broadly distributed across the landscape as a result

of longer timber harvest rotations, higher levels of green-tree retention, and larger

patches.

Our evaluation of this approach found no significant disadvantages of this approach

as compared to the Interim Plan. We felt that the differences in disturbance processes, stream flows, and potential long-term timber yields were minor relative to the

benefits described above, but we recognize that others will evaluate the advantages

and disadvantages differently.

Much of the benefits of this approach derive from the explicit use of historical disturbance regimes as a management template. Our use of long rotations and relatively

high levels of green-tree retention provided greater flexibility than the Interim Plan to

design aquatic reserves in keeping with past patterns. Riparian Reserves in the

Northwest Forest Plan protect existing resources and ecological processes and are a

critical part of the plan. This level of protection was necessary given the short rotations and low levels of green-tree retention built into the Matrix lands prescriptions in

the Northwest Forest Plan. The level of Riparian Reserves in the Interim Plan run the

risk of creating patterns inconsistent with legacies of historical forest ecosystems,

successional trends in forests, and patterns of historical disturbances.

Our ability to interpret potential consequences of these two scenarios was limited by

incomplete existing knowledge. We assumed, however, that managed landscape

patterns incorporating key features of historical patterns are more likely to incorporate

natural processes or species that are incompletely understood. Because the approach we have described was based on an understanding of historical disturbance

regimes, we feel this approach provides a better hedge against unknowns and

maintains more options for the future than does the Interim Plan.

The considerable uncertainties associated with predicting the consequences of this

management plan, or of other management plans, point out the value of comparing

alternative future management scenarios (phase 4). We evaluated two approaches by

using the Northwest Forest Plan as a benchmark and reference point for the disturbance-based approach. Many other approaches are possible, and a comparison of

their relative merits likely would yield insights and opportunities for blending the best

aspects of each. A logical step to follow a comparison of alternative scenarios would

be to refine a disturbance-based approach, such as we have described. For example,

results from a scenario designed around a high level of protection for the spotted owl

might be blended into a disturbance-based approach by altering the landscape block

mapping and scheduling rules to further protect the owl in the short term.
71

Numerous factors limited our ability to determine historical fire patterns. The age of

the oldest early seral tree species in the area (generally 500 years in the Augusta

area) limited the temporal length of the record available to read. The relatively small

spatial scale (approximately 7600 hectares [19,000 acres]) also may have limited our

ability to accurately interpret fire patterns. Confounding factors (e.g., accuracy of ring

counts, interpretation of scars as fire caused, age to stump or core height) reduced

the accuracy and precision of fire dates and extents. In addition, past climatic patterns may not match current or near-future climatic patterns. We therefore limited our

interpretations of historical patterns to a relatively general level. We described general

fire regimes and did not attempt to recreate the exact stand history of each site.

Research is currently underway on the west side of the Oregon Cascades to extend

both the temporal record, through paleological work (Sea and Whitlock 1995), and the

spatial scale, through compilation and integration of numerous databases.23

The apparent relation of fire occurrence and resulting stand structures with landforms

has been observed elsewhere (Barrett and Arno 1991) and may provide some degree

of long-term stability to landscape projections based on analysis of disturbance

regimes. Large-scale landforms do not vary significantly on the time scale of interest

but do exert a persistence influence on vegetation, fuel, microclimate, and wind

patterns that all influence fire behavior, severity, and frequency (Swanson and others

1993). Given the relatively short period of record available to read the fire history

(approximately 400 to 500 years), and the likelihood that climate will change, linking

landscape objectives and prescriptions to a persistent and ecologically significant

feature, such as landforms, may be useful.

Our analyses of historical disturbance regimes and landscape patterns revealed a

high level of temporal variability. Our projections of future landscape patterns are

based only on projected levels of management activities and depict a relatively

deterministic and uniform landscape pattern. Unplanned disturbance processes (e.g.,

windthrow, wildfire, landslides) cannot be completely suppressed, however, and will

interact with this pattern to create some difficult-to-predict hybrid of management

design and other disturbance processes. Hence, this disturbance overlay likely will

create much of the variability native to the ecosystem. More sophisticated planning

approaches integrating human-engineered disturbances with natural disturbances are

conceptually feasible, although the data and experience to do so are currently limiting.

The general approach to landscape management described in this paper should be

generally applicable in other landscapes and watersheds, but the mix of specific

elements and resulting consequences likely will differ considerably; for example, fire

and other types of disturbance patterns, and the conditions of stream networks and

flood plains, differ markedly across the region. Areas of highly fragmented or manipulated forest may require more reserves. Areas near wilderness or other undeveloped

lands may do well without an extensive aquatic reserve system. The presence of

threatened or endangered species, or of mixed ownership patterns, will likely impose

additional constraints.

Limitations of

Analysis

Application to Other

Landscapes

23Weisberg, P.J. 1996. Blue River fire regime analysis and description:

spatial variation in pre-settlement fire frequency, Blue River watershed,

central western Oregon Cascades. Corvallis, OR: Oregon State University.

17 p. Administrative report. On file with: Blue River Ranger District,

Willamette National Forest, P.O. Box 199, Blue River, OR 97413.
72

In this study, conditions across the larger surrounding river basins provided important

context for our interpretations and landscape prescriptions. Past practices, such as

clearcutting down to the stream, stream debris removal, and road building along

stream courses, have reduced the rate of woody debris delivery to channels, reduced

shade, altered riparian habitat, and had other ecological effects. In the Northwest

Forest Plan, the South Fork McKenzie is identified as a “Tier 1 Key Watershed”

because of the presence of bull trout. Because of these conditions, we provided a

relatively conservative aquatic reserve system. We used an understanding of disturbance processes to design an aquatic reserve system that, in our judgment, would

minimize chances of further decline in stream and fish values and promote riparian

recovery and is integrated with upslope management regimes.

An important implication of our analysis is that the approach we followed may not

make more timber available for harvest. Our results showed a small decrease (6 to

16 percent) in long-term timber yields with this approach. Variation in starting conditions or prescriptions could significantly change this number in either direction.

Fire—Much of the work reported in this paper emphasizes management prescriptions

that recreate landscape patterns through timber harvest that are similar to landscape

patterns created in the past through fire. However, our approach to sustaining ecosystems also includes maintaining important ecological processes, such as fire. Although

ranging greatly in frequency, severity, and extent, fire obviously has been a major

process in this area during the period when existing plant assemblages have occurred (Agee 1993, Sea and Whitlock 1995). Accordingly, our prescriptions included

the use of fire where feasible. It is not known, however, whether the restricted range

of fire behaviors allowed under a management scenario can adequately replace

historical fire regimes.

The consequences of fire exclusion are not well understood. In the 20th century, fire

suppression has been widely implemented, reducing the role of fire in the ecosystem.

Some changes in short fire-return-interval ecosystems, such as ponderosa pine

forests, are obvious, but changes along most of the west side of the Cascades, where

fire-return intervals are generally much longer, are less obvious. Nevertheless, there

is good reason to believe that some habitats and ecological processes in the Augusta

area depend on fire to some degree; for example, certain plant species produce

prolific amounts of seed when stimulated by heat from a fire. Other species germinate

from the soil seed bank after a fire and can dominate a site for decades. In the case

of the nitrogen-fixing snowbrush (Ceanothus velutinus) fire can serve an important

role in replenishing the nutrient capital of the site. Low-intensity fires may have played

an important role in the past in maintaining suitable habitat for the spotted owl by

reducing understories and generating snags (Morrison and Swanson 1990). Clearly,

much work is needed to understand the implications of fire exclusion.

The integrated use of fire and timber harvests are one key to sustaining a managed

forest ecosystem containing a full array of habitats and ecological processes. This will

be difficult to achieve, however. Timber sales are generally well funded and have a

strong, politically vocal constituency. Because of concerns with smoke, escaped fires,

intermingled ownerships, and long-standing antifire campaigns, prescribed fires are

not well funded and have active political opposition. A high probability exists that the

timber harvest portion of these prescriptions can move forward while the fire components languish. Ultimately, a focus on maintaining ecosystem performance requires a

hard evaluation of fire suppression, prescribed fire, and air quality policies.

Policy Implications
73

Relation to the Northwest Forest Plan—Considerable effort is currently going into

completion of watershed analyses for the National Forests and BLM districts covered

under the Northwest Forest Plan. The study described in this paper is both similar to

and different from these analyses. Phase 1 in this study was roughly analogous to

steps 1 to 4 (Characterization, Key Questions and Issues, Current Conditions, Reference Conditions) in “Ecosystem Analysis at the Watershed Scale: Federal Guide for

Watershed Analysis” (REO 1995); however, analyses in our study were strongly

keyed to understanding disturbance regimes. Disturbance regimes were described as

an interpretation of both landscape history and potential controls on the disturbance

process (e.g., topography and potential vegetation). In our view, disturbance regimes

provide a stronger and more generalized basis for design of management approaches than does an understanding of past conditions alone.

Steps 5 and 6 (Synthesis and Interpretation, Recommendations) in REO (1995) are

somewhat similar to phase 2 in our study. Expected products from steps 5 and 6 in

REO appear to be focused on identifying potential discrepancies among current

conditions and management objectives in the Northwest Forest Plan, capability to

achieve management objectives in the future, and recommendations for specific

projects in the watershed to achieve those objectives. The interpretations and recommendations in our study were integrated into general management prescriptions for

the planning area. The resulting landscape plan (phase 3) and evaluation of the

consequences (phase 4) are a significant departure from the way watershed analysis

generally is conducted but appear to be consistent with REO (1995).

A watershed analysis of existing conditions, historical trends, and disturbance regimes provides a framework for creating forest management approaches that retain

much of the historical patterns, processes, and composition in a future landscape.

The variability of landscapes, communities, and physical processes in time and space

can be reflected in future landscape and watershed objectives and in a landscape

management approach. The example shown here illustrates one process to integrate

this knowledge into landscape and watershed objectives that translate to spatially and

temporally explicit management prescriptions. Watershed analysis can provide the

context and information to select a management approach tuned to the watershed or

landscape under consideration.

Potential modification of the interim Riparian Reserves established in the Northwest

Forest Plan was one outcome expected by many to result from watershed analysis.

The interim reserves were meant to ensure that aquatic and riparian species and

functions are protected in watersheds where timber harvest occurs. Additionally,

many terrestrial species were assumed to benefit from the Riparian Reserve network.

This study provides an example of the type of analyses and landscape plan that we

feel results in an improved ability to meet the objectives expected of the interim

Riparian Reserve network, as well as better meet the overall objectives of the Northwest Forest Plan while improving operational flexibility.

Implementation of this approach faces hurdles, however. The regional design established in the Northwest Forest Plan (the Interim Plan) was evaluated in a formal

Environmental Impact Statement found to be legally sufficient. The landscape plan

developed in this case study has not been formally evaluated in a National Environmental Policy Act (NEPA) document. A NEPA document could be developed that

adopts this landscape plan by amending the Northwest Forest Plan for this particular
74

watershed. The NEPA procedures for such an amendment are relatively straightforward. The chief difficulty seems to be in reconciling a landscape-specific plan with the

species viability assessments conducted for the Northwest Forest Plan. To implement

our landscape management approach, a mechanism needs to be developed whereby

a landscape-specific plan can be evaluated to ensure that the viability of all species

covered under the Northwest Forest Plan are maintained at similar levels of risk.

Criteria need to be developed that link the assumptions underpinning the viability

assessments with landscape features. For example, a criterion could state that a

landscape plan providing at least the same amount of spotted owl dispersal habitat

(average stand diameter of 28 centimeters (11 in) and •40-percent crown closure) as

the Interim Plan would be sufficient to maintain the viability of the owl at the same

level as the Interim Plan. Criteria similar to this could be constructed for each of the

species or species groups evaluated in the NEPA documents for the Northwest Forest

Plan. Criteria could be interpreted directly from the assumptions used by the viability

panels in FEMAT (1993).

Even though all management is an experiment in a certain sense, we are entering a

period where forest management plans in the Pacific Northwest have never been

tested. The plan described here has no precedent. The need for monitoring and

adaptive management is just as high for this alternative landscape plan as it is for the

Interim Plan. Both are experimental and based on state-of-the-art professional

analysis. Both contain uncertainty and risks for the future of resources and ecosystems.

The approach we have described rests on the untested assumption that managing

within an interpreted range of historical variability can mimic natural ecosystems and

provide a full array of habitats and ecological processes.

This assumption needs an adaptive management program to evaluate its validity. The

adaptive management toolbox likely will contain:

• Modeling as a tool for capturing implicit assumptions of how forests function and

how they are anticipated to respond to management strategies.

• Experimentation on key questions and assumptions.

• Trend assessment of selected species, social factors, landscape conditions, and

ecological processes to identify important trajectories in ecological and social

system structure and function.

Each approach will generate new information. The management approach we have

described should be viewed as a concept based on current understandings of ecosystem and social processes. When the unforeseen occurs or new information

becomes available, potential modifications to the approach, or substitution of a new

approach, should be considered; for example, changes in the Landscape Plan may

be called for by changes in the surrounding watersheds or other changes such as

new listings of threatened or endangered species.

An understanding of historical patterns and ecosystem processes may be necessary

to manage for sustainable landscapes, but it is clearly not sufficient. Managing for

harmonious human interactions with the ecosystem is as essential as it is elusive.

Humans have long used the forest and continue to influence its composition and

function in myriad ways. We pursued a strategy placing human objectives within a

context of the local historical pattern; for example, many of the areas where human

Human Values

Adaptive

Management
75

uses have been concentrated (the river bottoms and main ridgelines) were placed in

reserve status. Finding acceptable balance points among perceived ecosystem needs

and perceived human needs remains fundamentally a social question.

In some respects this approach to landscape management offers a radically different

view of how humans can interact with the ecosystem. Past approaches have generally imposed an externally derived design on the local ecosystem, characteristic of

what Botkin (1990) termed the “machine-age view” of nature. Desired outputs were

determined and inputs applied to optimize production. The resulting prescriptions

were broadly implemented across the Northwest, with relatively little variation as

compared to historical disturbance regimes. The approach outlined here generated

management prescriptions based on characteristics and disturbance regimes intrinsic

to the local landscape. The resulting landscape plan is internally derived and rooted in

the natural and cultural history of the place. This perspective may now be appropriate

for Federal forests and needs further discussion.

An advantage of this approach is that it forces people to recognize and deal with the

dynamics of the system and the inevitability of disturbance. An advantage of the

landscape or watershed scale is that it is small enough to deal with the specific

choices that need to be made and large enough to see broad patterns. Thus, we feel

that this kind of exercise can be a valuable medium to foster urgently needed collaborative learning. Lasting progress on these issues will require mutual education and

discussion among public interests, scientists, policy makers, and managers.

The ability of ecologists and land managers to incorporate the new spatial and

temporal perspectives of ecosystem management is limited by several factors,

including the lack of analytical and modeling approaches to landscape-scale problems. Although the methodology employed in this study is a first step, there is a

significant need to further develop and use spatially explicit simulators of land-use

alternatives under both human and natural disturbances. Specific functional requirements include, in part, the integration of analytical and simulation methods for the

prediction and evaluation of potential disturbances, vegetative dynamics modeling,

hydrologic modeling, and habitat-association modeling for both plant and animal

species (Garman and others, in press). Many of these components are currently

available or are the subject of ongoing research efforts. But future research must

focus on synthesizing and integrating current understanding and predictive abilities

into a form for projecting and evaluating effects of land-use actions on the

sustainability of ecosystem properties.

We view this management approach as a potential postwatershed analysis implementation of the Northwest Forest Plan. Although the exact mechanisms for adjusting the

Northwest Forest Plan remain unclear, it is clear that changes in the plan were

anticipated to follow from watershed analysis. We hope this analysis can help identify

useful ways to improve implementation of the Northwest Forest Plan and better link

results of watershed analysis with planning. The landscape plan we developed in

phases 2 and 3 provides a direct link to project-scale planning. Explicit development

of landscape objectives and prescriptions and integration of these into a spatially and

temporally specific landscape plan lay the groundwork for a focused, efficient projectlevel planning process. Larger landscape- and watershed-scale issues have been

addressed and reconciled as best our collective judgment allows. The context and

landscape plan provided by this analysis can focus project-level planning for timber

sales, prescribed fire, silvicultural activities, and restoration or recovery projects.

Future Work

Conclusion
76

The Augusta Creek project has been a collaborative management-research venture

initiated and coordinated by the Cascade Center for Ecosystem Management, a

three-way partnership among Oregon State University, the Willamette National

Forest, and the Pacific Northwest Research Station. The mission of the center is to

develop information about how ecosystems function, integrate that information into

management strategies that meet social goals, and to communicate results with the

natural resource community.

We would like to particularly acknowledge two individuals who made significant

contributions to this project: we thank Tere Turner for the countless maps and database queries she delivered to us with amazing dedication and quality; and we thank

Miles Hemstrom, who helped initiate this project in 1991.

The following individuals also contributed to this project: Lynn Burditt, Kathy

Pendergrass, Karen Geary, George Lienkaemper, Jon Martin, Jeff McAllister, Cindy

McCain, Allison Reger, and Pam Skeels. Thank you for your support and review.

We thank the following reviewers: Tom Atzet, Ray Bosch, Neal Forrester, Richard

Hardt, Dave Hohler, Mark Huff, Gary Marsh, and Art McKee.

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Press. 495 p.

Aho, R.S. 1976. A population study of the cutthroat in an unshaded and shaded

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Barrett, S.W.; Arno, S.F. 1991. Classifying fire regimes and defining their topographic controls in the Selway-Bitterroot Wilderness. In: Andrews, P.L.; Potts, D.F.,

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The Forest Service of the U.S. Department of Agriculture is dedicated to the principle of multiple use management of the Nation’s forest resources for sustained

yields of wood, water, forage, wildlife, and recreation.

Through forestry research, cooperation with the States

and private forest owners, and management of the

National Forests and National Grasslands, it strives—as

directed by Congress—to provide increasingly greater

service to a growing Nation.

The United States Department of Agriculture (USDA)

prohibits discrimination in its programs on the basis of

race, color, national origin, sex, religion, age, disability,

political beliefs, and marital or familial status. (Not all

prohibited bases apply to all programs.) Persons with

disabilities who require alternative means of communication of program information (Braille, large print,

audiotape, etc.) should contact the USDA’s TARGET

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

To file a complaint, write the Secretary of Agriculture,

U.S. Department of Agriculture, Washington, DC 20250,

or call (800) 245-6340 (voice), or (202) 720-1127 (TDD).

USDA is an equal employment opportunity employer.

Pacific Northwest Research Station

333 S.W. First Avenue

P.O. Box 3890

Portland, Oregon 97208-3890

Cissel, John H.; Swanson, Frederick J.; Grant, Gordon E.; Olson, Deanna H.;

Stanley, Gregory V.; Garman, Steven L.; Ashkenas, Linda R.; Hunter,

Matthew G.; Kertis, Jane A.; Mayo, James H.; McSwain, Michelle D.;

Swetland, Sam G.; Swindle, Keith A.; Wallin, David O. 1998. A landscape

plan based on historical fire regimes for a managed forest ecosystem: the

Augusta Creek study. Gen. Tech. Rep. PNW-GTR-422. Portland, OR: U.S.

Department of Agriculture, Forest Service, Pacific Northwest Research Station.

82 p.

Vegetation management regimes governing the frequency, intensity, and spatial

pattern of future timber harvest activities were derived from historic fire regimes for

a 7600-hectare study area in western Oregon. Results showed a greater amount

of late-successional habitat, large patches, and better habitat connectivity across

the landscape than would result from literal application of standards and guidelines in the Northwest Forest Plan.

Keywords: Landscape ecology, landscape management, landscape planning, fire

history, range of historical variability, watershed analysis, fire ecology.
U.S. Department of Agriculture

Pacific Northwest Research Station

333 S.W. First Avenue

P.O. Box 3890

Portland, OR 97208

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