Software for Calculating 

Vegetation Disturbance 

and Recovery by Using 

the Equivalent Clearcut 

Area Model

Alan A. Ager and Caty Clifton

United States 

Department of 

Agriculture

Forest Service

Pacific Northwest 

Research Station

General Technical 

Report

PNW-GTR-637 

April 2005
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.

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activities on the basis of race, color, national origin, gender, religion, age, disability, political 

beliefs, sexual orientation, or marital or family status. (Not all prohibited bases apply to all 

programs.) Persons with disabilities who require alternative means for communication of 

program information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET 

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

To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326-

W, Whitten Building, 14th and Independence Avenue, SW, Washington, DC 20250-9410 or 

call (202) 720-5964 (voice and TDD). USDA is an equal opportunity provider and employer.

USDA is committed to making its information materials accessible to all USDA customers 

and employees.

Authors

Alan A. Ager is an operations research analyst, and Caty Clifton is a forest 

hydrologist, Umatilla National Forest, 2517 SW Hailey Ave., Pendleton, OR 97801.
Abstract

Ager, Alan A.; Clifton, Caty. 2005. Software for calculating vegetation disturbance and recovery by using the equivalent clearcut area model. Gen. Tech. Rep. 

PNW-GTR-637. Portland, OR: U.S. Department of Agriculture, Forest Service, 

Pacific Northwest Research Station. 11 p.

The use of cumulative watershed effects models is mandated as part of interagency 

consultation over projects that might affect habitat for salmonids federally listed as 

threatened or endangered. Cumulative effects analysis is also required by a number 

of national forest plans in the Pacific Northwest Region (Region 6). Cumulative 

watershed effects in many cases are measured with the equivalent clearcut area 

(ECA) model, which generates an index of cumulative disturbance by considering disturbance type, extent, and recovery over time. Although the model has 

many limitations, it provides an index of vegetative disturbance that can be used to 

compare the existing condition of different watersheds, and the potential impacts 

among land management alternatives. Calculating ECA on multiple watersheds and 

management scenarios for project-level analysis is a tedious process. We automated 

the process with a program called Equivalent Treatment Area Calculator to streamline its application on national forests in the Blue Mountains of eastern Oregon. The 

program, operation, and limitations of the ECA model are described in this paper. 

Keywords: ECA, equivalent clearcut area, cumulative watershed effects, 

equivalent roaded area.

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Software for Calculating Vegetation Disturbance and Recovery by Using the Equivalent Clearcut Area Model

Introduction

Understanding and modeling the cumulative watershed effects of management and 

natural disturbance is a significant challenge for land managers (U.S. Council on 

Environmental Quality 1997). Cumulative watershed effects can result from minor 

actions taking place over a period of time that collectively are thought to alter hydrologic response (FEMAT 1993). A wide variety of qualitative and quantitative methods for analyzing cumulative watershed effects have been developed over the past 25 

to 30 years (Berg et al. 1996, Reid 1993). One of the earliest quantitative approaches 

used by the Forest Service was the equivalent clearcut area (ECA) method, which 

accounts for past and future effects of different types of disturbances by standardizing the effects and modeling the recovery over time. It was originally developed for 

use in northern Idaho and Montana (King 1989, USDA FS 1974) where it was used 

to measure the potential impacts of alternative timber harvesting schedules. A more 

encompassing model, equivalent roaded area (ERA), was later developed in the 

Pacific Southwest Region by using the same framework, and was extensively used in 

the Sierra Nevada Ecosystem Project (Menning et al. 1997). 

Both models assume a direct linkage between vegetation disturbance and hydrologic response (i.e., peak flows and water yield) (Bosch and Hewlett 1982, Stednick 

1996). Despite conficting literature on the existence of these linkages and other 

limitations (Beschta et al. 2000, Menning et al. 1997), the model is still required for 

consultation with the National Oceanic and Atmospheric Administration (NOAA) 

Fisheries Department and the U.S. Fish and Wildlife Service (USDC NMFS 1995, 

USDI FWS 1998) for all proposed management actions in the Blue Mountains 

national forests and elsewhere within the range covered by PACFISH (USDA USDI 

1995a) and INFISH (USDA USDI 1995b) policies. An ECA analysis is typically 

applied at the subwatershed scale (10,000 to 40,000 acres) as part of analyzing 

alternative management actions developed in the National Environmental Policy 

Act (NEPA) project analysis. Equivalent clearcut area measures are also relevant to 

standards and guidelines for many of the current national forest plans that specify 

maximum treatment acreages on a subwatershed basis over time. For the Umatilla 

National Forest, there is no explicit ECA standard in the forest plan, but an ECA of 

15 percent is used as a surrogate for a forest plan standard that allows a maximum of 

30 percent of the forested area in a subwatershed to be in the 0 to 10-year age class. 

The ECA model uses one set of coefficients to describe the proportion of the 

total basal area removed for different disturbance types, including harvest prescriptions, wildfire, prescribed fire, roads, and insect mortality. A second set determines 

how fast the treated acres recover to 100 percent of potential leaf area or canopy 
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GENERAL TECHNICAL REPORT PNW-GTR-637

closure, at which point the acre is assumed to have hydrologic function the same as 

an untreated acre. The physical model behind ECA as a cumulative-effects measure 

is that vegetation removal changes water yield characteristics (peak flow, timing, 

total yield) in rough proportion to leaf area, or basal area removed from a site. 

Several studies have shown that timber harvest affects water yield by reducing 

water loss associated with interception and evapotranspiration, or by changing 

snow distribution and melt rates (Hicks et al. 1991, Scherer 2001, Stednick 1996). 

The hydrologic changes may lead to destabilized stream channels and other adverse 

ecological effects (Reid 1993). The ECA statistic (percentage of area in equivalent 

clearcut condition) is typically used in conjunction with climatic data to evaluate 

the cumulative effects of vegetative removal on water yields and peak flows. The 

ECA statistic also may be used as a general guide to overall watershed condition 

when coupled with site-specific evaluations. 

Calculation of the ECA statistic can be a time-consuming process for watersheds that have received multiple disturbances over time. Calculations are complicated by the consideration of multiple treatment alternatives and revision of 

treatment intensities in the process of project development. This paper describes 

the program Equivalent Treatment Area Calculator (ETAC) that vastly simplifies 

calculation of the ECA statistic. The ETAC program is intended to provide a consistent approach to measuring harvest and other impacts to forest vegetation. This 

paper describes the most recent version of the program, methods for preparing data, 

considerations for use of the model, and includes an example analysis. 

ETAC Software

Program Overview and Requirements 

The ETAC program evolved from prototype software developed in 1994 by the 

authors and has been in continual use on the Umatilla National Forest for analyzing ECA on a number of forest management projects. The program evolved with 

each application, resulting in the current version that offers a relatively streamlined 

process for calculating the ECA statistic. The current software and example data 

are available from http://www.fs.fed.us/r6/uma/ager. 

The ETAC was developed in object Pascal as implemented in Borland Delphi 

61 (Borland Software Corporation, Scotts Valley, CA). Database connectivity was 

encapsulated into the program by using Microsoft ActiveX Data objects (ADO) 

version 2.5. Key features of the program include the ability to process a large 

1 The use of trade or firm names in this publication is for reader information and does not 

imply endorsement by the U.S. Department of Agriculture of any product or services.
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Software for Calculating Vegetation Disturbance and Recovery by Using the Equivalent Clearcut Area Model

number of spatial units (e.g., subwatersheds) and alternative management scenarios 

from a single database. Each combination of alternative and subwatershed is evaluated individually and written as one record to the output database. 

The ETAC requires about 2 MB of random access memory (RAM). The application requires the installation of ADO 2.1 or later on the client computer. The 

ADO and OLE DB are part of the Microsoft Data Access Control components supplied by Microsoft and installed with Windows 98 and later Windows versions. 

Program Operation

The program interface accepts entries for the input and output databases, and the 

number of years to evaluate. The input database must be a valid Microsoft ACCESS 

database, and the data must be contained within a table named ETARUN within the 

database. An example input database (ETAC.MDB) is provided with the program. 

The required field names and field formats for the database are shown in table 1. 

Table 1—Required fields and format for the Equivalent Treatment Area Calculator 

input database

Field name Format Explanation

Alternative Integer from 1 to 10 Harvest alternative

Year cut Integer Year of past or proposed treatment

SWS Alpha, up to 10 characters Subwatershed (HUC 6) of past or 

 proposed harvest 

Acres cut Real The number of acres harvested

Forested acres Real The total acres that could potentially 

 support forest vegetation in the 

 subwatershed

ECA Real The equivalent treatment coefficient 

 associated with the treatment

HUC 6 = sixth-order hydrologic unit code.

The order of the fields within the database is not important. Any additional fields 

in the input database are ignored by the program. The output database is specified 

without an extension. In addition to input and output databases, the user specifies 

the starting year for the evaluation and the number of years to calculate ECA. The 

run is commenced with the Run button. The output database contains fields for the 

subwatershed, project alternative label, the total ECA acres, and the ECA statistic 

for each alternative by subwatershed (SWS) combination (table 2). 
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GENERAL TECHNICAL REPORT PNW-GTR-637

Preparation of the Input Database

An example input database is provided with the program (ETAC.MDB) to illustrate 

formats and data conventions. The database does not need to be sorted, and additional fields beyond those shown in table 1 can be included. However, the field 

names for fields in table 1 must be exactly as shown. Input databases are built in 

a multiple-step process that begins with geographic information system (GIS) 

operations to determine acres harvested by year, subwatershed, harvest prescription, and potential vegetation group. The exact sequence of events for completing 

these calculations depends on the GIS formats, and thus can only be described 

in general. Typically, the relevant GIS layers (i.e., all past and proposed harvest 

activity layers by SWS) are processed with a UNION operation in ArcGIS, and the 

attribute table is exported to a database that contains the year and prescription for 

all past and proposed treatment areas. A relational query between this database 

table and one containing the ECA coefficients and recovery rates (ETAC_COEFF 

table in ETAC.MDB) is then performed. Field names may need to be changed to 

match those required by the program. Total forested subwatershed acreage is added 

to the database by a similar relational query of the appropriate vegetation database. 

Forested acres represent the total acres potentially forested as determined from the 

potential vegetation layer. 

The ECA treatment coefficients are intended to approximate the proportion of 

the basal area removed from a stand for each prescription type, and recovery rates 

are specific for each potential vegetation group. Local specialists (Johnson and 

Mrowka 1993) originally developed the draft coefficients for the Umatilla National 

Forest (table 3), which are being continually refined and adjusted to reflect current 

information. Note that for each plant group there are only three possible recovery 

Table 2—Fields and format of the output database for the Equivalent Treatment 

Area Calculator (ETAC) program

Field name Format Explanation

Alternative Integer from 1 to 10 Harvest alternative

Year Integer Year of past or proposed treatment

SWS Alpha, 1 to 12 characters Subwatershed code

ECA acres Real The sum of the equivalent treatment acres 

 for the alternative by SWS combination 

Forested acres Real The total acres that potentially could grow 

 trees in the subwatershed. These data are 

 copied from the input database

ECA Real Percentage of forested acres in the sub-

 watershed in equivalent clearcut condition

Note: ETAC outputs one record for each combination of project alternative and subwatershed.
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Software for Calculating Vegetation Disturbance and Recovery by Using the Equivalent Clearcut Area Model

rates, the fastest for thinning-type prescriptions, the slowest for regeneration 

harvests, and an intermediate recovery rate for shelterwood/seed tree cuts (table 4). 

Often project specialists modify these coefficients to meet site-specific conditions. 

Coefficients for prescriptions that involve salvage, prescribed fire, and other irregular treatments need to be derived specifically for each project. Professional judgment is required in some instances to assign ECA coefficients to particular prescriptions, especially ones that involve uneven harvesting (e.g., salvage). 

Table 3—Equivalent treatment area coefficients by prescription type

Prescription Equivalent treatment

code Description area coefficient

HCPH Regeneration harvest, clearcut, patch 1.0

HCSP Regeneration harvest, clearcut, strip 1.0

HCSD Regeneration harvest, clearcut, stand 1.0

HPSW Regeneration harvest, prep cut, three-stage shelterwood .6

HSSW Regeneration harvest, seed cut, three-stage shelterwood .2

HSSW Regeneration harvest, combined seed/prep cut, two-stage shelterwood .8

HRSW Regeneration harvest, removal cut, two- or three-stage shelterwood .2

HPST Regeneration harvest, prep cut, three-stage seed tree .6

HSST Regeneration harvest, seed cut, three-stage seed tree .3

HSST Regeneration harvest, combined seed/prep cut, two-stage seed tree .9

HRST Regeneration harvest, removal cut, two- or three-stage seed tree .1

HROS Regeneration harvest, removal cut, seed tree .1

HSEI Regeneration harvest, select cut, individual tree .3

HSEG Regeneration harvest, select cut, group 1.0

HPRC Regeneration harvest, partial removal .3

HIIM Intermediate harvest methods, improvements .25

HITH Intermediate harvest method, thin .3

HISM Intermediate harvest method, lodgepole salvage 1.0

HISS Intermediate harvest method, sanitation Proportion of basal 

 area removed

HISM Intermediate harvest method, mortality salvage

Table 4—Recovery coefficients and years to recover by prescription group and potential vegetation group 

Equivalent

Plant association

treatment Moist forest Cold forest Dry forest

area Recovery Years to Recovery Years to Recovery Years to

Prescription coefficient coefficient recovery coefficient recovery coefficient recovery

%/Year %/Year %/Year

Regeneration harvest 1.0 4.3 23 3.0 30 3.0 33

 (clearcut or heavy salvage)

Seed tree/ shelter prep .6 to .9 5.3 19 3.6 26 3.6 28

Thinnings, partials, select cuts <.6 8.3 12 4.4 18 4.4 22
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GENERAL TECHNICAL REPORT PNW-GTR-637

Consideration of Roads in the ETAC Model

Roads both within and outside of harvest units may be included in ECA calculations. Typically, roads are given an ECA coefficient of 1.0 and a recovery rate of 0, 

although other approaches have been used (Menning et al. 1997). The area of roads 

is best determined by querying the transportation layer for the total length in each 

subwatershed and assuming an average width. Roads are in some ways functionally clearcut areas, although more compacted, so infiltration is reduced and runoff 

rates may be more accelerated than in a true clearcut. There has been considerable 

discussion about the role of roads in ECA calculations. If roads are omitted from 

the calculations, the rationale should be documented. 

Discussion

The ECA statistic encapsulates the history of vegetative disturbance within a 

watershed and can provide a broad indicator of the potential for change in water 

yields and peak streamflow from forest management activities. However, ECA 

is one of many measures of watershed health and is not directly predictive of 

increased peak flows or impacts to streams. The ECA procedure has had many 

criticisms owing to inadequate explanation of the ECA analysis in environmental 

documentation, lack of a standard procedure for its calculation, and lack of interpretation using collateral data. A consistent relationship between the ECA statistic 

and hydrologic variables (peak flows and water yields) has not been established 

(Beschta et al. 2000, Scherer 2001). Typically, the ECA statistic for a given subwatershed is compared with an established ECA threshold (15 percent in the biological opinions in USDC NMFS 1995, and USDI FWS 1998). Supporting information 

from other indicators of watershed health is useful to interpreting ECA results and 

predicting the likelihood of adverse effects. 

In terms of the application of the ECA procedure on the Blue Mountains 

national forests in eastern Oregon, we have identified a number of additional 

limitations and suggestions for appropriate uses, as described below:

The original ECA method was developed in north Idaho and Montana where 

spring snowmelt runoff is the dominant mechanism generating streamflow. In areas 

like the Blue Mountains of eastern Oregon, streamflow is generated from multiple 

hydrologic processes including spring snowmelt and winter rain on snow. Variable 

climate (maritime and continental), geology, and disturbance (fire, floods, wind) 

also exert strong influences on water yields and peak flows.

Using one ECA threshold (15 percent), as required in the 1995 and 1998 biological opinions (USDC NMFS 1995, USDF FWS 1998) ignores the variability among 
7

Software for Calculating Vegetation Disturbance and Recovery by Using the Equivalent Clearcut Area Model

subwatersheds in their vegetative disturbance cycles. Thus each subwatershed 

has a background level of vegetative disturbance that, over time, contributes to a 

background ECA. 

The ECA measure as currently applied is calculated based on forested land 

rather than the total area within a watershed. Forest management in watersheds that 

are only partially forested is highly constrained by ECA, even though the overall 

hydrologic condition of a watershed with a relatively small amount of forest is more 

closely related to the condition of the nonforest lands, and other disturbances like 

grazing may be a more significant influence on watershed health. 

At present, there are limited data on the recovery rates of herbaceous and shrub 

vegetation, which can rapidly restore some of the hydrological/soil problems caused 

by harvesting activities, such as erosion and sedimentation. Future development of 

the ECA model should consider these vegetation types as well. 

The ECA model is best used in conjunction with other relevant data to further 

assess potential for changes in water yield and peak flows, and impacts to stream 

channels and riparian areas. Specifically, climatic and streamflow data from nearby 

stations should be examined to characterize streamflow-generating mechanisms, 

including timing and volume of runoff, and stream survey data should be evaluated 

to assess channel stability. 

Mixed ownership and the lack of vegetation information on non-Forest Service 

lands make it impractical to accurately measure ECA for all lands within many 

watersheds. 

Example Analysis

The example analysis is from the Pedro/Colt Timber Sale and Fire Reintroduction 

Project on the Walla Walla Ranger District, Umatilla National Forest. This project 

is located in the Upper Grande Ronde subbasin and considers four management 

alternatives within five subwatersheds. Thus ECA measures are required through 

time for the 20 combinations of subwatersheds and management alternatives. The 

proposed management uses a landscape approach to restore ecosystem functions 

on about 9,200 acres by using prescribed fire and timber harvest. Timber harvest is 

proposed to reduce stocking levels and modify the fuel structure prior to igniting 

prescribed fire on about 10,560 acres. Harvest is focused in stands with structural 

components that deviate from historical fire regimes and that are at risk for catastrophic damage. Silvicultural prescriptions include shelterwood, seed-tree cuts, 

thinning, and improvement harvest. Landscape-scale prescribed fire, by both aerial 

and on-the-ground ignition, would occur on about 7,800 acres. Some stands may 
8

GENERAL TECHNICAL REPORT PNW-GTR-637

take multiple ignitions to reach the desired fuel composition. The landscape 

treatments would occur over a 10- to 15-year period.

The example database for this area is the ETACRUN table in the ETAC.MDB 

database. Fields are present for management alternatives, total forested acres, acres 

cut, and ECA coefficients. The results of running these data through ETAC (fig. 1) 

show large differences in ECA among the subwatersheds for both existing and 

future conditions. Clearly, subwatershed 84C, and to a lesser extent 84E and 84I, 

have relatively high ECA percentages, although only alternative D in subwatershed 

84C exceeds the 15 percent threshold. Watershed 84C maintains a relatively high 

ECA percentage into the future, whereas most of the others show minor residual 

effects from management activities. Note that the no-action alternative (A) projects 

a 0 percent ECA into the future; thus the program does not predict risks from 

(assumes no chance of) natural disturbances (wildfire, insect outbreaks). 

Figure 1—Results of the equivalent clearcut area (ECA) analysis for the Pedro/Colt timber sale, Walla Walla Ranger 

District, Umatilla National Forest. Chart shows the ECA levels by subwatershed and project alternative through time. 

Alternatives B, C, and D are different management alternatives for thinning and underburning forest stands within 

the Pedro/Colt project area.
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Software for Calculating Vegetation Disturbance and Recovery by Using the Equivalent Clearcut Area Model

Acknowledgments

Bruce McCammon and Stacia Peterson provided helpful reviews on an earlier 

version of this paper. We thank Cari McCown for data and results for the ECA 

example analysis for the Pedro-Colt project. We are grateful to Linda Dillavou for 

editorial assistance. 

Metric Equivalents

1 acre = 0.405 hectares

Literature Cited

Berg, N.H.; Roby, K.B.; McGurk, B.J. 1996. Cumulative watershed effects: 

applicability of available methodologies to the Sierra Nevada. In: Sierra 

Nevada Ecosystem Project; final report to Congress. Davis, CA: University of 

California–Davis, Centers for Water and Wildland Resources: 39–78. Vol. 3. 

Chapter 2.

Beschta, R.L.; Pyles, M.R.; Skaugset, A.E.; Surfleet, C.G. 2000. Peakflow 

response to forest practices in the western Cascades of Oregon, USA. Journal of 

Hydrology. 233: 102–120. 

Bosch, J.M.; Hewlett, J.D. 1982. A review of catchment experiments to determine 

the effect of vegetation changes on water yield and evapotranspiration. Journal 

of Hydrology. 55: 3–23.

Forest Ecosystem Management Assessment Team [FEMAT]. 1993. Forest 

ecosystem management: an ecological, economic, and social assessment. 

Portland, OR: U.S. Department of Agriculture; U.S. Department of the Interior 

[and others]. 

Hicks, B.J.; Beschta, R.L.; Harr, R.D. 1991. Long-term changes in streamflow 

following logging in western Oregon and associated fisheries implications. 

Water Resources Bulletin. 27: 217–226. 

Johnson, C.; Mrowka, R. 1993. Draft recovery coefficients for the equivalent 

clearcut area model. 3 p. Unpublished working paper. On file with: Land 

Management Planning, Umatilla National Forest, 2517 SW Hailey Ave., 

Pendleton, OR 97801. 

King, J.G. 1989. Streamflow responses to road building and harvesting: a 

comparison with the equivalent clearcut area procedure. Res. Pap. INT-401. 

Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain 

Research Station. 13 p.
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GENERAL TECHNICAL REPORT PNW-GTR-637

Menning, K.D.; Erman, C.; Johnson, K.N.; Sessions, J. 1997. Modeling aquatic 

and riparian systems, assessing cumulative watershed effects, and limiting 

watershed disturbance. In: Sierra Nevada Ecosystem Project: final report to 

Congress. Davis, CA: University of California, Centers for Water and Wildland 

Resources.

Reid, L.M. 1993. Research and cumulative watershed effects. Gen. Tech. Rep. 

PSW-GTR-141. Berkeley, CA: U.S. Department of Agriculture, Forest Service, 

Pacific Southwest Research Station. 118 p. 

Scherer, R. 2001. Effects of changes in forest cover on streamflow: a literature 

review. In: Watershed assessment in the southern interior of British Columbia: 

workshop proceedings. Working Pap. 57. Vancouver, BC: Ministry of Forestry: 

44–55. 

Stednick, J.D. 1996. Monitoring the effects of timber harvest on annual water 

yield. Journal of Hydrology. 176: 79–95. 

U.S. Council on Environmental Quality. 1997. Considering cumulative effects 

under the National Environmental Policy Act. Washington, DC: Executive 

Office of the President. 48 p. 

U.S. Department of Agriculture, Forest Service [USDA FS]. 1974. Forest 

hydrology part II—hydrologic effects of vegetation manipulation. 229 p. 

Unpublished report. On file with: Natural Resources, Umatilla National 

Forest, 2517 SW Hailey Ave., Pendleton, OR 97801. 

U.S. Department of Agriculture, Forest Service; U.S. Department of the 

Interior, Bureau of Land Management [USDA USDI]. 1995a. Interim 

strategies for managing anadromous fish-producing watersheds in eastern 

Oregon and Washington, Idaho, and portions of California (PACFISH). 68 p. 

U.S. Department of Agriculture, Forest Service; U.S. Department of the 

Interior, Bureau of Land Management [USDA USDI] 1995b. Interim 

strategies for managing fish-producing watersheds in eastern Oregon and 

Washington, Idaho, western Montana, and portions of Nevada (INFISH). 

U.S. Department of Commerce, National Marine Fisheries Service [USDC 

NMFS]. 1995 (March 1). Memo to USFS Regional Foresters. Endangered 

Species Act Section 7 biological opinion on the land and resource management 

plans for the Boise, Challis, Nez Perce, Payette, Salmon, Sawtooth, Umatilla, 

and Wallowa-Whitman National Forests. 138 p. On file with: Forest Hydrologist, 

Umatilla National Forest, 2517 SW Hailey Ave., Pendleton OR 97801. 
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Software for Calculating Vegetation Disturbance and Recovery by Using the Equivalent Clearcut Area Model

U.S. Department of the Interior, Fish and Wildlife Service [USDI FWS]. 

1998. Effects to bull trout from continued implementation of land and resource 

management plans as amended by the interim strategy for managing anadromous 

fish-producing watersheds in eastern Oregon and Washington, western Montana, 

and portions of Nevada (INFISH), and the interim strategy for managing 

anadromous fish-producing watersheds in eastern Oregon and Washington, 

Idaho, and portions of California (PACFISH). Portland, OR. 120 p. 

Pacific Northwest Research Station

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