Microcomputer Software for Calculating an 

Elk Habitat Effectiveness Index on Blue 

Mountain Winter Range

Mark Hitchcock and Alan Ager
Erratum

Publication: Microcomputer Software for Calculating the

Elk Habitat Effectiveness Index on Blue Mountain Winter

Range, PNW-GTR-301, July 1992

Authors: Mark Hitchcock and Alan Ager

Software: The HEICALC software can be obtained by

emailing Alan Ager at aager@fs.fed.us.
Authors MARK HITCHCOCK is a consulting forester, 2347 Old Day Creek Road, Sedro

Woolley, WA 98284; and ALAN AGER is an operations research analyst, U.S.

Department of Agriculture, Forest Service, Umatilla National Forest, 2517 Hailey

Avenue, Pendleton, OR 97801.

This work is part of cooperative agreement PNW89-648 for the Starkey Research

Development and Application Program between the Pacific Northwest Research

Station and the Pacific Northwest Region of the Forest Service.
Abstract Hitchcock, Mark; Ager, Alan. 1992. Microcomputer software for calculating an

elk habitat effectiveness index on Blue Mountain winter ranges. Gen. Tech. Rep.

GTR-PNW-301. Portland, OR: U.S. Department of Agriculture, Forest Service,

Pacific Northwest Research Station. 13 p.

National Forests in the Pacific Northwest Region have incorporated elk habitat

standards into Forest plans to ensure that elk habitat objectives are met on multiple

use land allocations. Many Forests have employed versions of the habitat effectiveness index (HEI) as a standard method to evaluate habitat. Field application of

the HEI model unfortunately is a formidable problem, owing largely to the detailed

calculations of "spacing bands" that describe the spatial arrangement of forage and

cover areas. This paper describes a DOS microcomputer program that automates

the calculation of HEI. "HEICALC" is a simple, menu-driven program that will run on

virtually any DOS microcomputer. HEICALC vastly simplifies the task of measuring

elk habitat conditions over large areas. It is especially useful in projects where

several management alternatives are evaluated for their effects on elk habitat. A

floppy diskette containing a copy of the program is distributed with the publication.

Keywords: Elk habitat, HEI, wildlife software, Blue Mountains.

Introduction The habitat effectiveness index (HEI) is a quantitative measure of habitat quality for

elk. It was developed to provide wildlife biologists with a tool to objectively quantify

use of habitat by elk. Several variants of HEI have been developed to account for

differences in habitat use by geographic area and for summer versus winter range in

Oregon (Black and others 1976; Thomas and others 1979, 1988; Wisdom and others

1986). While research to validate these models continues, HEI has found wide application for measuring and monitoring elk habitat. Nearly all National Forests in the

Pacific Northwest Region have incorporated HEI standards into Forest plans as part

of their land use allocations. Field assessment of HEI is a formidable problem, owing

largely to the detailed calculations of "spacing bands" that describe the spatial arrangement of forage and cover areas. We therefore began work to automate HE[

calculations and started with the Blue Mountain winter range model (Thomas and

others 1988). This report describes the result: a DOS microcomputer program called

"HEICALC."1 We provide a general description of the program and detailed instructions for its use.

The Elk Winter The HEICALC program calculates HEI from coefficients of habitat use for winter

Range Model ranges published by Thomas and others (1988). This model evaluates four habitat

components: the size and spacing of cover and forage areas, the density of roads

traveled by motorized vehicles, the quantity and quality of forage, and the quality of

cover. Each is measured with subindexes ranging from 0.0 (no value) to 1.0 (optimum

condition). The HEI is computed as the geometric mean of these subindexes as

follows:

HElsrfc = (HEs x HEr x HEf x HEc)1/N ,

where:

HEs = habitat-effectiveness index derived from size and spacing of cover and forage areas;

HEr = habitat-effectiveness index derived from the density of roads open to vehicular traffic;

HEf = habitat-effectiveness index derived from the quantity and quality of forage;

HEc = habitat-effectiveness index derived from cover quality; and

1/N = Nth root of the product taken to obtain the geometric mean, which reflects the compensatory 

interaction of the N factors in the HE model.

Getting Started HEICALC is written and compiled in TURBO Pascal, 2 version 6.0, and operates on

Hardware Requirements IBM-compatible microcomputers with DOS version 2.0 or later. HEICALC automatically detects the type of video display installed (for example, monochrome, VGA,

EGA, CGA) and takes advantage of the capabilities of each. A 1.2-megabyte (MB)

floppy drive is required to read the distribution diskette. HEICALC prints on most

printers by using the standard ASCII printer control characters to control formatting.

Random access memory (RAM) requirements depend on project area size; at least

130 kilobytes (KB) must be available to load the program and process habitat maps

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 service.

2 TURBO Pascal is a registered trademark of Borland

International, Scotts Valley, CA.

2

 having 60,000 pixels (31,000 acres for maps with 50- by 50-yard pixels). Larger

 maps require more memory. The maximum map size accommodated by the 

 program, 600 columns by 800 rows (ca. 240,000 acres at 50- by 50-yard pixel size)

 requires 540K RAM. A math coprocessor and a mouse with a Microsoft-compatible 

 driver are optional equipment.

Installation The distribution diskette contains five files. HEICALC.EXE is the executable program

 for calculating HEI. SAMPLE.MAP and SAMPLE.DB are a sample habitat map and a

 database, respectively. HEIUTIL.EXE is a utility program facilitating the conversion

 of MOSS-MAPS geographic information system (GIS) data to the HEICALC format.

 B.COM is a file-browsing utility that can be used in conjunction with HEIUTIL.EXE.

 No special installation routines are necessary to run HEICALC or the accessory

 programs. They can be run directly from the distribution diskette or copied onto a

 hard drive. It is convenient to create a subdirectory (for example, C:\HEI) on the

 hard drive into which the files can be copied and the program executed.

Program Overview HEICALC.EXE calculates HEI components from a digital habitat-type map and from

numerical data on forage and open road mileage. Open road mileage and forage

quality and quantity data are entered from the keyboard with each HEICALC session

by using menu options. Cover data are derived from a habitat map constructed for

each project area. The habitat map is an ASCII computer file in which an original line

map has been translated into a grid of square pixels of a fixed area. The pixel size

can be set by the user, the maximum size being 100 yards on a side (2.066 acres).

The cover type of each pixel (for example, satisfactory cover, marginal cover, forage)

is represented by one of four codes as shown in table 1. As an example, figure 1A

shows the map published by Thomas and others (1988, p. 14), and figure 1 B shows

the same map in HEICALC format.

Methods Used by The calculation of the individual HE components by the HEICALC is described briefly

HEICALC for below. Refer to Thomas and others (1988) for details.

Calculating HEI

The HEs to measure the size and spacing of forage and cover areas is calculated

by HEICALC with a search algorithm that moves to each pixel on the map and

determines the linear distance to the nearest pixel of opposite habitat type (forage

versus cover). The distance is used to classify the pixel and associated acreage for

the distance bands. The HEs is then calculated by using the weighting factors as

described in Thomas and others (1988). The classification of pixels into distance

bands is illustrated in figure 2 for the example map in figure 1.
The HEr to measure the effect of open road density is calculated according to equations developed by 

Lyon (1983), as depicted in figure 2 of Thomas and others (1988). The appropriate equation depends 

on the road density. If the road density (RD) is less than 1.1 miles/per square mile then,

HEr = 0.4 + [(6 - RD)/6]6 x 0.6

If the road density is greater than or equal to 1.1 miles/per square mile but less than 2 miles/per square 

mile then,

HEr = 0.486 + 0.092 x (2-RD)/0.89

If the road density is greater than or equal to 2 mile/per square mile but less or equal to 6 miles/per 

square mile then,

 HEr = 0.104 + (6-RD)/4 x 0.382

 If the road density is greater than 6 miles/per square mile then HEr = 0.104.

 Hence, an analysis area with no open roads has an HEr value of 1.0. An open road density greater 

than 6.0 has an HEr value of 0.104.

3
The HEf to measure the quantity and quality of forage is measured from two subindexes, HEquant 

and HEqual. HEICALC uses the following linear equation, derived from the graph presented for the 

Blue Mountains grassland steppe (Thomas and others 1988) to calculate HEquan:

HEquan = (0.0094)(coverage in percent) + 0.06.

Forage quality (HEqual) is based on the weight of forage remaining after October 1. Thomas and others 

(1988) present a graphic relation between remaining forage weight and remaining forage height; a 

second graph shows the relation between remaining forage weight and habitat effectiveness. HEICALC 

combines these graphs to create a table of values directly relating remaining forage height and HEqual 

(table 2). HEf is calculated as the geometric mean of the forage quantity and quality 

habitat-effectiveness scores.

4
 The HEc to measure the quality of cover is calculated as the weighted proportion of

 cover occupied by each habitat type, as described in Thomas and others (1988, p. 17).

 The proportion of area in each cover type is multiplied by a weighting factor and summed.

 The weighting factors are 1.0 for satisfactory cover and 0.5 for marginal cover.

A Quick Demonstration This section provides instructions to demonstrate the HEICALC program and its

capabilities. Insert the distribution diskette in the A: drive and type "HEICALC". Press

any key after viewing the opening screen. Note the help window, which contains

program operation and calculation parameters. The "PgUp" and "PgDn" keys are

used to browse through five pages of help information. The "Esc" key is used to

close the help window. Press the "/" key to obtain the main menu. Selections from

this menu are activated by typing the capitalized letter of each menu option. Load the

sample map by selecting the "Map" and "Load" menu options (type "M" and "L"), and

then type "SAMPLE.MAP" and press the "Enter" key. The sample map will now be

loaded and displayed on the screen. In this map, each code represents a square

pixel of 50 yards on a side (0.517 acre). The codes "1" and "3" denote forage and

satisfactory cover, respectively. The cursor location can be changed by pressing the

four arrow keys. In the lower left corner, the definition of the habitat code is displayed

for the current position of the cursor.

The habitat map contains the information required to calculate two of the four habitat

parameters-HEs and HEc-which measure the size and spacing of the cover and

forage areas and the cover quality. Additional information to calculate the HE for

roads can be input for each map. From the menu selections, choose "Options" and

"Roads" and enter an open road mileage. Input forage by choosing "Options" and

"Forage" from the menu. In this demonstration, we ignore the forage options and let

HEICALC use default values included in the program. HEI now can be calculated by

choosing "Run" from the main menu. The results will be sent output to the screen

(fig. 3) and can be sent to a printer or a file by responding appropriately to the

prompts displayed on the lower screen.

5
 To see the "what-if" capabilities of HEICALC for timber sale planning,

 use the arrow keys to position the cursor within an area of cover habitat (map code "3"). 

 Harvest treatments are applied to habitat maps by changing map codes to "4", 

 either with the keyboard or the mouse. Clicking the left mouse button will change

 the habitat code at the mouse cursor to the last code entered from the keyboard.

 HEICALC assumes that treatments in cover areas create forage areas. Each pixel 

 that is changed represents treatment of 0.517 acre. When a harvest unit has been

 outlined in this manner, run HEICALC again to see changes in the HE that have

 resulted from the treatments. Each alternative developed in this manner can be saved

 as a separate habitat map by choosing "Map" and "Save" from the main menu.

 To quit HEICALC, choose "Quit" in the main menu.

The HEICALC To activate the main menu in HEICALC, press the "/" key. The complete menu

Command Menu system is shown in figure 4. Select a menu choice by pressing the letter key corresponding to the first letter of each command. The user may exit a menu without

selecting a command by pressing the "Esc" key. Selecting a command either causes

a program action, displays a submenu, or prompts for user-supplied information.

Prompts ending with a question mark generally expect a "yes" or "no" response

(the lone exception is the "Options Forage Species" command). Pressing the "Y"

key corresponds to a "yes" response; any other key corresponds to a "no" response.

Prompts that end with three dots are generally status messages indicating an action

that the program is currently executing; however, if such a prompt contains the message "Press any key", the program halts execution until the user completes the

action requested and presses any key, thereby signaling the program to continue.

Prompts ending with a colon expect the user to type an appropriate response. Some

prompts will display a default response.

6
Loading, Viewing, The "Map" command is used to toad existing maps, save newly created or changed

Editing, and Printing maps, print maps, and to clear the map display so that a new map can be created.

Maps All these operations are accessed on a submenu that appears after the "Maps"

command is invoked, as explained below.

Loading maps-The "Load" command reads from an existing habitat maps file. If

the specified file name is not found, the prompt for the file name is redisplayed for

editing and re-entry. If the specified file name is found, the map display is cleared

automatically, an open database will be closed, and the map is loaded into memory.

Map files must conform to the standard ASCII convention, commonly referred to as

"text files." The ASCII convention calls for an end-of-line sequence (ASCII code 13

followed by ASCII code 10) at the end of each line. In addition, an end-of-file marker

(ASCII code 26) must exist at the end of the file. If standard text editors are used to

create maps, or the maps are generated with the procedures outlined later in this

paper, the map files conform to the ASCII convention. If maps are created with

word processors, they must be saved as "text files." When maps are loaded, every

character on the line is read, but only the characters corresponding to known habitat

codes ("1" through "4", table 1) will appear in the map. Characters and numbers not

used by HEICALC (all other numbers and letters in the alphabet) become blanks in

the map. If characters with ASCII codes of less than 32 appear in the map (special

characters and symbols), they are ignored during the load process, thereby compacting map rows and possibly realigning columns. Any map lines containing more

characters than the maximum number of map array columns (600) are truncated.

Any map file lines exceeding the maximum number of map array rows are ignored.

7
Viewing maps-Once a map is loaded, it can be viewed and edited. The location of the highlighted 

cursor can be changed, within the limits of the map array, by several means. The four arrow keys move 

the cursor to adjacent pixels. The "PgUp" and "PgDn" keys display the next screen portion of the map 

above and below, respectively, the current display. Holding the "Ctrl" key down white pressing the right 

or left arrow displays the next screen portion of the map to the right or left of the current display. 

Pressing the "Home" key moves the cursor to the upper left corner of the map array, and pressing the 

"End" key moves the cursor to the bottom right corner of the map. The latter corner is the intersection of 

the last column and last row containing a habitat code; it is not necessarily equivalent to the bottom right 

corner of the map array.

Editing maps-Habitatcodes contained in the map can be added, changed, or deleted during a viewing 

session. Pressing any of the keys corresponding to valid habitat codes (table 1) accordingly replaces the 

contents of the pixel highlighted by the cursor. It also is possible to change habitat codes with a mouse; 

pressing the left mouse key replaces the pixel contents with the last habitat code typed from the

keyboard. Blank pixels can be added to the analysis area by this method, and the

contents of any highlighted pixel can be erased by pressing the "Del" key, thereby

placing that pixel outside the analysis area.

Saving maps-Maps are saved by using the "Save" command. Maps also can be saved whenever the 

"Load", "Clear", and "Quit" commands are activated, which automatically prompt the user to save any 

changes made since the map was last saved. Choosing to save a map with the save command calls 

the file save process, described as follows. The user is first prompted to specify the name of the map 

file to save. The map file name must be composed of letters and numbers and can include a file name 

extension. A drive designator and path also can be specified. If the specified file name is found, a 

prompt to overwrite the existing file is displayed on the status line. Choosing not to overwrite will 

redisplay the save file name for editing and re-entry. If a file name is not entered after invoking the 

"Save" command, the map is not saved, and the program will return to the map display.

Printing maps-The "Print" command sends the current map to an attached printer. The map is printed 

on numbered pages containing 128 columns and 56 rows with map coordinates in the margins. The 

printer must be capable of printing 132 characters per line and 60 lines per page. Printers that use only 

letter-size paper must be set for compressed print mode. The user will be prompted to press any key 

when the printer is on-line and ready to receive the map. A bell rings to alert the user if printing problems 

occur.

Clearing the viewing screen-The "Clear" command clears the map array. Once

the array is cleared, a new map can be created by entering habitat codes directly. It

is not necessary to "Clear" before loading a map file because "Load" also clears the

map array. If changes have been made to the current map, the user is prompted to

save the current map and the save process is called. "Clear" also will close an open

database.

8
Changing Defaults: The "Options" command changes HEI calculation default parameters associated with

Forage, Roads, forage quantity and quality, open road miles, and map pixel size. Changes made to

Pixel Size, default parameters are not saved and must be specified anew with each HEICALC

and Display session. Selecting the "Options" command leads to a submenu of the default

parameters, as described below.

Forage parameters-The "Forage" command is used to specify the forage species,

percentage of cover, and percentage of grass height remaining after October 1.

Selecting the "Forage" command leads to a submenu of command choices to specify

forage parameters for species, coverage, and height.

The "Species" command allows the user to choose between bluebunch wheatgrass

(Agropyron spicatum) and Idaho fescue (Festuca idahoensis) as the dominant

grassland community species within the map analysis area. The default choice is

bluebunch wheatgrass. The current species selection is always shown within

parentheses at the end of the prompt. Pressing "F" or "B" will select either Idaho

fescue or bluebunch wheatgrass as the grassland community type. Pressing "Esc"

will return to the map display without changing the current species selection.

The "Coverage" command prompts the user to input the percentage of herbaceous

plant cover that is comprised of decreasers. The default is 20 percent, but valid input

ranges from 1 to 100 percent. Entering 0 (zero) percent will return the program to the

map display without changing the current coverage percentage.

The "Height" command prompts the user to input the percentage of height remaining

on the decreaser species on October 1. The default is 30 percent, but valid input

ranges from 1 to 100 percent.

Open road mileage-Selecting the "Roads" command prompts the user to input the

number of miles of road open to vehicular traffic within the map analysis area. The

default is zero, but valid input ranges from 0 to 9999.9 miles. Any valid entry will

change the current number of road miles.

Map pixel size-Selecting the "Pixels" command prompts the user to input the

number of feet per side of the map pixels. The default is 150 feet, but valid input

ranges from 66 to 300 feet. Entering 0 (zero) feet will return the program to the

map display without changing the current pixel size.

Display attributes-If an EGA or VGA graphics adapter is installed, the "Toggle"

command will appear on the "Options" menu. This option switches the display to

43 (EGA) or 50 (VGA) lines from the standard 25 lines. More of the map can be

seen with increased line modes.

Calculating HEI and The "Run" command calculates HEI from the cover map and its associated

9
10

Using the Database HEICALC has a database feature that allows databases to be linked to habitat maps.

Feature of HEICALC The "Database" command is used to access an ASCII database file associated with

the current map. Each record of the database corresponds to a pixel address and

has five 10-character fields containing attributes pertaining to the pixel. Once a

database has been linked to the current map, the user can display the attributes of

the pixel covered by the highlighted cursor. This feature is useful for associating

attributes such as stand numbers with the current map. The user can opt to create a

subset of a linked database, which contains records only for those pixels marked as

treated areas with habitat code "4". Other database software can then be used to

perform calculations on the attribute data associated with pixels marked for treatment.

The timber volumes of treated pixels could be summed, for example, to produce an

estimate of the harvest volume associated with a particular HEI.

Databases to link with HEICALC must be an ASCII file sorted in order of row

(y-coordinate) within column (x-coordinate). The file must end with an end-of-file

marker (^Z or ASCII code 26). Each line (record) in the database file must begin

with the number 8 and finish with an end-of-line sequence (ASCII codes 13 and 10).

In addition, each line must have 56 characters between the number 8 and the

end-of-line sequence. The first six characters are the pixel address with which to

associate the attribute data; they are followed by five 10-character attribute fields.

All attribute fields must exist regardless of usage. Unused fields should be filled with

spaces if no data are available. Many types of software, such as database managers,

word processors and spreadsheets, can be used to create and maintain a database.

But the structure and sorting requirements must be met for the HEICALC software to

properly access the associated data.

The required format of the database files is as follows:

Selecting the database command leads to a submenu of the commands to link,

unlink, and spool databases. These functions are described below.

Linking a database- Databases are linked to a habitat map by using the "Link"

command. If a map is currently displayed, selecting the "Link" command prompts the

user to specify the name of the database file to link. Any database currently linked to

the map closes automatically before linking the newly specified database. The message "F2 Shows Attributes" is displayed on the status line whenever a database is
 linked to the current map. Pressing "F2" causes the linked database to be searched

 for a record corresponding to the address of the pixel covered by the highlighted cursor.

 If such a record is located, the record attributes are displayed on the status line. Otherwise,

 the message "Attribute Data Not Found" is displayed. Press any key to clear the status

 line and return to the current map when finished viewing the displayed attributes.

 To demonstrate the database linking procedure, the SAMPLE.DB file on the distribution

 diskette can be linked to SAM PLE.MAP by using the above procedures. Next, position

 the cursor on any pixel in the map and press the "F2" key. Attributes from the database

 are displayed along the bottom of the screen.

Unlinking databases- Databases are unlinked and closed with the "Unlink" command.

Spooling databases- The spooling feature provides a method of reporting the database attributes for all pixels that

 have had habitat codes changed to treated (habitat code "4"). The user is first prompted

 to specify the name of the database file to which records are spooled. Entering no file

 name does not spool the database and instead returns the program to the map display.

 At the completion of the file spool process, the program returns to the map display.

 The spooling feature can be demonstrated with the SAMPLE.DB file on the distribution map.

 After loading SAMPLE.MAP and linking SAMPLE.DB, change some of the habitat codes to

 "4", thereby signifying a treatment. Invoke the "Spool" command and enter a file name. Exit

 the program, and view the spooled data with B.COM program (contained on the distribution

 diskette) by typing "B filename", where filename is the name given to the spooled data. These 

 data then can be imported to a database used to describe affected resources.

Quitting the Program HEICALC is terminated with the "Quit" command. If changes have been made to the

current map since it was last saved, "Quit" prompts the user to save the current map.

Obtaining Habitat Measuring HEI requires maps of forage and cover areas and data on open road

Maps for HEICALC mileage, forage quality, and forage quantity. There are many methods for obtaining

these data, and, in the case of the cover maps, formatting the data for HEICALC.

The following section describes in detail the data type and format requirements for

HEICALC. The automated data capture and summary procedures described here

are specific to the MOSS-MAPS GIS used by the USDA Forest Service in the Pacific

Northwest Region.

There are several ways to obtain cover maps for HEICALC. In all methods, the

starting point is a cover map showing polygons of the basic habitat types, forage,

and marginal and satisfactory cover. One method for converting these maps into

a text file of cover codes is to overlay a Mylar grid constructed so that each pixel

corresponds to the selected pixel size (for example 50 by 50 yards, or 0.517 acre)

on the cover map, and code the value of each pixel directly on the Mylar. The codes

are typed directly into an ASCII file with any editor. Mylar grids can be generated

with CAD software.

11
 With GIS (MOSS-MAPS) software, cover maps can be digitized, rasterized

 (converted to a pixel map), and exported. In MOSS, vector (line) maps are converted

 to raster format with the "Polycell" command and choosing "Subject Number Assignment".

 Maps should be polycelled to a pixel size of 25, 50, or 100 yards on a side. Our testing indicates

 that a pixel size of 50 by 50 yards (0.517 acre) produces good resolution and minimizes

 errors in the raster process. When prompted by MOSS in the polycell process, enter 0.517

 acre with a pixel ratio of 1. The map type is "Discrete", "Type 7", and pixels are assigned by

 "Subject Number" (option 5).

 Exporting the map is most easily accomplished with the MOSS "SPSS" command,

 which produces an ASCII data file containing row, column, and map subject. This same

 technique can be used to generate databases to link with habitat maps. When prompted

 in the SPSS procedure whether to eliminate empty cases, choose "yes". After downloading

 to the microcomputer, this file is processed with HEIUTIL.EXE program distributed with

 HEICALC to regenerate the map. The polycelled map should be examined to ensure that

 MOSS assigned values to map subjects according to the format required by HEICALC

 (see table 1). To determine if the map requires recoding, examine the raster map subjects by

 using the "Describe" command. If subjects are incorrectly coded, they can be recoded 

 within the HEICALC program.

Optimal Pixel Size HEICALC can process maps having pixels between 0.1 and 2.066 acres. The

for Habitat Maps maximum size of 2.066 acres is determined by the distance bands in the HEI model

being in increments of 100 yards, and a 100-yard-square pixel is 2.066 acres. For

HEICALC to function as intended, pixels should have dimensions evenly divisible

into 100 (for example, 25 or 50 yards). Thus the optimum pixel sizes are either 25,

50, or 100 yards on a side, which corresponds to 0.129, 0.517, and 2.066 acres,

respectively. Our tests with cover maps of winter range in the Blue Mountains

showed that a pixel size of 0.517 acre is the most efficient scale. Larger pixel sizes

(for example, 2.066 acres) resulted in a loss of small "stringers" of cover during the

polycell process in MOSS. These small cover areas may not be significant in terms

of elk habitat use (see Thomas and others 1988), but we believe their deletion from

the habitat map should be performed by wildlife biologists rather than by GIS

software. In addition, with 100- by 100-yard pixels, the diagonal distance between

pixels centers is 141.42 yards, and thus habitat comparisons between diagonal

pixels contribute to the 101- to 200-yard spacing band. These problems are largely

nonexistent with pixel sizes of 0.517 or 0.129 acre. The only problem with using a

smaller pixel size is that map arrays become somewhat large and processing time

is increased.

Acknowledgments Partial funding for this project was provided by the Blue Mountains Elk Initiative. The

authors acknowledge Alan Scott, William Peterson, and Cecilia Noyes for testing

early prototypes of the HEICALC software. Valuable comments to this manuscript

were provided by Jim Merzenich and Mike Wisdom.

12
Literature Cited Black, H.; Schersinger, R.; Thomas, J.W. 1976. Relationships of Rocky Mountain

elk and Rocky Mountain mule deer to timber management in the Blue Mountains

of Oregon and Washington. In: Hieb, S.R., ed. Elk-logging-roads: Proceedings of a

symposium. [Dates of symposium unknown]; [Location of symposium unknown].

Moscow, ID: University of Idaho: 11-31.

Leckenby, D.; Isaacson, D.L.; Thomas, S.R. 1985. Landsat application to elk

habitat management in northeast Oregon. Wildlife Society Bulletin. 13: 130-134.

Lyon, J. 1983. Road density models describing habitat effectiveness for elk. Journal

of Forestry. 81: 592-595.

Thomas, Jack Ward; Black, Hugh, Jr.; Scherzinger, Richard J.; Pedersen, R.J.

1979. Deer and elk. In: Thomas, Jack Ward, tech. ed. Wildlife habitats in man

aged forests--4he Blue Mountains of Oregon and Washington. Agric. Handb. 553.

Washington, DC: U.S. Department of Agriculture: 104-127.

Thomas, J.W.; Leckenby, D.A.; Henjum, M. [and others]. 1988. Habitat

effectiveness index for elk on Blue Mountain winter ranges. Gen. Tech. Rep.

PNW-GTR-218. Portland, OR: U.S. Department of Agriculture, Forest Service,

Pacific Northwest Research Station. 28 p.

Wisdom, M.J.; Bright, L.R.; Carey, C.G. [and others]. 1986. A model to evaluate

elk habitat in western Oregon. R6-F&WL-216-1986. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Region. 36 p.

13
Hitchcock, Mark; Ager, Alan. 1992. Microcomputer. software for calculating an elk 

habitat effectiveness index on Blue Mountain) winter ranges. Gen. Tech. Rep. 

GTR-PNW-301. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific 

Northwest Research Station. 13 p.

National Forests in the Pacific Northwest Region have incorporated elk habitat 

standards into Forest plans to ensure that elk habitat objectives are met on multiple 

use land allocations. Many Forests have employed versions of the habitat effectiveness 

index (HEI) as a standard method to evaluate habitat. Field application of the HE] 

model unfortunately is a formidable problem, owing largely to the detailed calculations 

of "spacing bands" that describe the spatial arrangement of forage and cover areas. 

This paper describes a DOS microcomputer program that automates the calculation of 

HEI. "HEICALC" is a simple, menu-driven program that will run on virtually any DOS 

microcomputer. HEICALC vastly simplifies the task of measuring elk habitat conditions 

over large areas. It is especially useful in projects where several management 

alternatives are evaluated for their effects on elk habitat. A floppy diskette containing a 

copy of the program is distributed with the publication.

Keywords: Elk habitat, HEI, wildlife software, Blue Mountains.

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 U.S. Department of Agriculture is an Equal Opportunity Employer. Applicants for all 

Department programs will be given equal consideration without regard to age, race, color, 

sex, religion, or national origin.

Pacific Northwest Research Station 333 S.W. First Avenue P.O. Box 3890 Portland, 

Oregon 97208-3890

U.S. GOVERNMENT PRINTING OFFICE: 1992-694-862/63,003 

REGION NO. 10