United Stares

Departmentof

Agriculture

Forest Service

Pacific Northwest

ResearchStation

General Technical

Report

March 1992

PNW-GTR-300

DF PRUNE Users Guide

Roger D. Fight, James M. Cahill and Thomas D. Fahey

This file was created by scanning the printed publication. Text errors identified 

by the software have been corrected; however, some errors may remain. 
Authors

The DFPRUNE software is in the public domain and the recipient may not assert any

 proprietaryrights thereto or represent them to anyone as other than Governmentproduced programs. 

The DFPRUNE software is provided “as is” without warranty of any kind, including 

but not limited to the implied warranties of merchantabilityand fitness for a particular 

purpose. The user assumes all responsibility for the accuracy and suitability of these

programs for a specific application.

In no event will the Pacific Northwest Research Station be liable for any damages,

including lost profits, lost savings, or other incidental or consequentialdamages,

arising from the use or inability to use this program.

DFPRUNE is distributed by the Forest Resources Systems Institute (FORS), a

nonprofit organization for forestry computer support. A fee is charged to cover the

costs of disks, postage, handling, and telephone support to answer questions from

users. For information on ordering a machine-readable copy, write or call:

The Forest Resources Systems Institute

122 Helton Court

Florence, Alabama 35630

(205) 767-0250

ROGER D. FIGHT is a principal economist, JAMES M. CAHILL was a research 

forester (currently with Bonneville Power Administration, Portland, Oregon), and

THOMAS D. FAHEY is a research forester, Forestry Sciences Laboratory, P.O. Box

3890, Portland, Oregon 97208-3890.
Abstract

Contents

Fight, Roger D.; Cahlll, James M .; Fahey, Thomas D. 1992. DFPRUNE users

guide. Gen Tech. Rep. PNW-GTR-300. Portland,OR: U.S. Department of

Agriculture, Forest Service, Pacific Northwest Research Station. 12 p.

The DFPRUNE spreadsheet programis designed to estimate the expected financial

return from pruning coast Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. 

menziesii). It is a significant revisionof the PRUNE-SIM program. The PRUNE-SIM

programwas based on the average product recovery for unpruned logs from a single

stand that received frequent light thinnings. The DFPRUNE program incorporates new

recovery information for unpruned young-growth Douglas-fir and can be used to assess the economic potentialof pruning for a wide range of management regimes. 

Product prices and descriptions of trees at time of pruning and at time of harvest must

be supplied by the user. The DFPRUNE program was developedfor the Lotus 1-2-3

spreadsheet and should work on versions 2.01 or later.

Keywords: Douglas-fir,pruning, forest product value, product recovery, simulation.

1

1

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2

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4

4

7

7

8

a

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9

11

12

12

Introduction

Comparison of DFPRUNE and PRUNE-SIM

Format

Input Data 

Cautions

How To Use DFRUNE

Program Input and Program Output

Intermediate Calculations 

Veneer Analysis

Diameter of PrunedTrees

Average Limb Diameter on Unpruned Trees 

Effect of Crown Removal on Growth of Pruned Trees 

Macro Feature in DFPRUNE

Summary

Metric Equivalents

Literature Cited

Introduction A recent lumber and veneer recovery study of pruned Douglas-fir (Pseudotsuga

menziesii (Mirb.) Franco var. menziesii) logs shows significant increases in highquality lumber and veneer with pruning (Cahilland others 1988).A financial analysis

of pruning Douglas-fir (Fight and others 1987a) done with the PRUNE-SIM software

(Fight and others 1987b) shows that many situations can occur where the expected

returnfrom pruning will exceed a real rate of 4 percent.

In the past several years, pruning has gone from a practice not seriously considered

as an operational silvicultural tool on the NationalForests to one being used operationally on several National Forests. The number of acres being prunedon National

Forests in Oregon and Washington has increased as shown in the following tabulation:

Fiscal year Pruning on National Forests

Comparison of

DFPRUNE and

PRUNE-SIM

Format

1987

1988

1989

1990

1991

Acres

244

56

422

2433

5768

The DFPRUNEsoftware was developed to estimate the return to pruning by comparing the value of the butt log (16.5 feet for lumber and 17.0 feet for veneer) of a

pruned tree with the value of the same log if the tree was not pruned. The comparison can be applied to a range of regimes represented by trees of different sizes at

time of pruning and time of harvest.

The DFPRUNE software is a major revision of the PRUNE-SIM software (Fight and

others 1987b). This revision incorporates lumber and veneer recovery for unpruned

logs from a recent recovery study of intensively managedyoung-growth Douglas-fir

(Fahey and others 1991). Financial analyses of pruning done with the DFPRUNE

software are more realistic than those done with PRUNE-SIM, because the recovery

from unpruned logs can represent a wide variety of management regimes. The data

in the PRUNE-SIM software were representativeof a single unpruned stand managed

with frequent light thinnings.

The format of DFPRUNE has been redesigned so that all the input data and results

for the lumber analysis are contained on the home screen (upper left corner of the

spreadsheet). The input data have been grouped vertically to facilitate data entry.

A section has been added to store the tree input data used in a set of analyses. This

facilitates making a set of sensitivity analyses with modified data or different price or

cost assumptions.

Additional macros have been added to allow the user to more easily do multiple

analyses and sensitivity analyses. The macros also print the results of each analysis

and save the input data for future reference or use.

1
Input Data

Cautions

The required input data is the same as for PRUNE-SIMwith the exception that it is

necessary to add three additional items: limb size on the butt log at time of pruning,

limb size on the butt log of unpruned trees at the time of harvest, and the diameter 

breast height (d.b.h.) at a breast height age of 20. The limb size variable is the average of the largest limb in each quadrant of the butt log. Limb size is used in estimating the grade recovery of the unpruned core of the pruned log and the grade recovery

of the unpruned log. The d.b.h. at a breast height age of 20 is used to estimate the

proportion of the log that is juvenile wood, which also is used in estimating grade 

recovery.

The cost of pruning can be input to DFPRUNE. If a cost is used, the increase in

present value that results is the increase in present net worth from pruning. If costs

are entered, they should include the costs of management and administration as well

as the cost of actually doing the pruning. If a cost of zero is used, the increase in

present value that results is the breakeven cost of pruningor the maximum that could

be spent for pruning and still achieve the specified rate of return. Two present value 

calculations will be made. If only one interest rate is input, one of those calculations 

will be made with an interest rate of zero.

Prices required for DFPRUNE are for the same grade categories as those found in

Warren (1992) and Haynes and Fight (1992). Grade recovery estimates are for different categories in some cases. The prices for these categories are calculated by the 

spreadsheet as follows:

1.Price for “SEL” is the average of the prices of C select category and the D select

and shop category.

2. Price for “2100f” is 1.05 times the price of structural items.

3.Price for “1650f” is 0.95 times the price of structural items.

4. Price for “1450f” is 1.05 times the price of light framing.

The 1450f, 1650f, and 2100f grades are machine stress rated (MSR) grades for which

prices are not readily available. 

Users familiar with PRUNE-SIM probably can use DFPRUNE after only a brief study

of the new format for input data and results. For those wanting to do an extensive

analysis, it also will be helpful to look at the section “Macro Feature in DFPRUNE.”

A complete description of the DFPRUNE program follows the section on “Cautions.”

1. Users should exercise judgment when doing analyses outside the range of the tree 

sizes sampled and should remember that the recovery estimates are basedon pruning of only the first 16.5- or 17-foot butt log.

2. Users should be aware that additional costs of managing pruned stands that occur

after the stands are pruned are not considered in this analysis.

3.Users should recognize the uncertainties of predictingfuture prices of clear wood

products.

Grade recovery of pruned butt logs was based on a sample of trees from a range of

sites and a small geographic area. The stand was of natural origin and had been 

repeatedly thinned but was maintained at denser stocking than now is common (Cahill 

and others 1988). Figure 1shows diameters of sample trees at time of pruning and

time of harvest.

2
Figure 1- Distribution of sample trees by d. b. h.. at time of pruning and d. b. h. at time of harvest

Grade recovery of unpruned butt logs is based on a sample of trees from a wide geographic area, a wide range of ages, and a wide range of stocking. See Fahey and

others (1991) for a discussion of the recovery study and the sample trees. So that all

the lumber could be machine stress graded, it was agreed that the mill would not cut

any material in dimensions larger than 2 by 6 inches. The grade recovery from that

study has been adjusted to account for the fact that grade recovery of large logs with

large limbs is increased when sawing patterns are selected that produce dimensions 

larger than 2 by 6.

No statistically significant difference was found in the volume recovery for pruned and

unpruned logs in the pruning recovery study (Cahill and others 1988). To eliminate

mill differences, the volume recovery estimates in DFPRUNEfor both pruned and 

unpruned logs are based on that study.

The only cost that is used in DFPRUNE is the cost of pruning. This cost should include the cost of management and administration as well as the cost of actual pruning. Additional costs are ignored; for example, additional record keeping. In a reasonably competitive stumpage market, buyers will be willing to pay a premium for pruned

logs that reflectsthe increase invalue resulting from recovery of clear wood products

This is the rationale for using the difference in product value as the basis for evaluating the returns from pruning. Convincing buyers of the quality of pruned logs may

require records showing tree or stand descriptions. Even if the trees obviously were

pruned, documented proof of the size of trees at time of pruning may be necessary

so that the amount of clear wood can be estimated. 

3
How To Use

DFPRUNE

The characteristics of clear wood products producedfrom pruned young-growth

Douglas-fir are different from similar products from old-growth Douglas-fir.One key

difference is appearance. As long as clear wood productsfrom old growth are available, the market is likely to be biased against clear wood from pruned young growth.

This bias likely will diminish when clear wood products from old growth are no longer

available in sufficient quantity to meet the demand without large price increases.

The DFPRUNE software was intendedto facilitate two types of analysis:

1. The user can enter informationfor a single tree and a single set of product prices

and view the results. All this is done in the home screen of the spreadsheet.

2. Or the user can enter one or,twosets of product prices (in section A25..H38) and

use the macros to calculate and store the results of a series of analyses for different

sites, rotation ages, prices, or other conditions. A more complete discussion of the

macros is found below.

The DFPRUNE software has protectionon all parts of the spreadsheet except those

parts where the user must input data and those parts that must be unprotectedfor

the macros to work. This protection helps to guard against accidental alterations of

the equations in the program.

Figure 2 shows the general layout of the DFPRUNE spreadsheet program. The

spreadsheet consists of four blocks. The first block contains the lumber analysis,

intermediatecalculations relating to grade recovery and log diameters, the macros,

and the macro subroutines. The second block contains the veneer analysis and the

start-up screen for the program. The third block is where the results of a series of

analyses will be stored if the macros are used. The fourth block is where the input

data from a series of analyses will be stored if the macros are used.

Figure 3 is an example of the lumber analysis that shows the input and output for a

single analysis of pruning. For a single analysis, prices and other input data are entered in columns B and D. For a single veneer analysis, it is necessary to use both

this screen and the one shown infigure 4 where the veneer prices and cost savings

are input. When macros are used, the lumber and veneer prices are entered insection A24..H30. Most headings have a hidden definitionthat can be viewed at the top

of the screen by putting the cursor on the heading. Following is a detailed description

of the input data:

B1-SITE, site index (optionaland not used in the program; any combination of numbers and alpha characters can be used to identify different analyses)

B2-STK, stocking (optionaland not used in the program; any cornbination of numbers and alpha characters can be used to identify different analyses)

B3-AGE2, age at time of harvest

B4-DBH2,diameter of tree at time of harvest

B5-HTH2, height of tree at time of harvest

B6-LDH, average diameter of largest limb in each quadrant of log at time of harvest

B7-TREES, number of trees pruned per acre

B8-AGE1, age at time of pruning

Program Input and

Program Output 

4

B9__DBH1, diameter of tree at time of pruning

B10__HTH1,height of tree at time of pruning

B11-LDP,average diameter of largest limb in each quadrant of log at time of

pruning

B12__DBHBH20, diameter breast height at breast height age of 20

B13__SUCCESS, proportion of prunedtrees surviving to harvest

B14__COST, cost of pruningper tree

B15__PCSEL, price of C select lumber in dollars per thousand board feet ($/mbf)

B1__PDSEL&, price of D select and shop lumber ($/mbf)

B17__PSTR, price of structural items ($/mbf)

B18__PLTFR, price of light framing lumber ($/mbf)

819__PUTIL, price of utility lumber ($/mbf)

B20__PECON, price of economy lumber ($/mbf)

D2__RATE1, first interest rate used in calculating present values (decimal)

D3__RATE2, second interest rate used incalculating present values (decimal),

optional

D4__LENG, length of pruned log for lumber (should not be changed)

Followingis a detailed description of the results:

D7__DSP,diameter inside bark of the small end of the saw log at time of pruning

(inches)

D8__DLP, diameter inside bark of the large end of the saw log or veneer log at time

of pruning (inches)

D9__DJ, diameter inside bark of juvenile wood cylinder (inches)

D10__DSH, diameter inside bark of the small end of the saw log at time of harvest

(inches)

D11__DLH,diameter inside bark of the large end of the saw log or veneer log at time

of harvest (inches)

D12__TAPER, saw-log taper at time of harvest (inchesper foot of length)

D13__JWH, percentage of the saw log that is juvenile wood at time of harvest

D14__CLR, percentage of the pruned saw log that is clear wood at time of harvest

D15__CF, volume of the saw log at time of harvest (cubic feet)

D16__LRF, lumber recovery factor (boardfeet lumber tally per cubic foot of log

volume)

G4..HS__percentage veneer recovery by grade for the pruned and unpruned log

G12, H12__$/mbf, value per mbf (thousand boardfeet) for the pruned and unpruned

log

6
Intermediate

CalculatIons

Veneer Analysis

G13, H13__BF, volume of lumber (boardfeet) (will always be the same for pruned

and unpnrned logs)

G14, H14-$/Log, value of prunedand unpruned saw log or veneer log (dollars)

G17, H17__PNWRATE1,increase inpresent net worth or present value per tree and

per acre with the first interest rate (dollars)

G18, H18__PNW RATE2, increase in present net worth or present value pertree and

per acre with the second interest rate (dollars)

The section in figure 2 labeled “Intermediate Calculations’’ includes equations for calculating the lumber grade recovery of unpruned logs by log diameter class. The calculations for logs less than 8 inches use the equations directly out of Fahey and

others (1991). The calculationsfor larger logsuse equations modified to estimate the

effect of cutting patternsthat permit productionof dimensions largerthan 2 by 6. Calculations are made only for the diameter class that contains the size of log in the current analysis. Calculations for veneer grade recovery also are found here. Grade recovery equations for veneer come directly from the study by Fahey and others (1991).

The section labeled“Intermediate Calculations”also containsthe cells where prices

are entered when macros are used. When a macro is used the prices must be entered here rather than in the home screen.

The section in figure 2 labeled“Log sizes” is where the log diameters at time of

pruning and time of harvest are calculated. The procedures described in Fight and

others (1987b) were used.

Figure4 shows the analysis of pruningfor veneer; it is similar to the sectionfor

lumber. The DFPRUNEspreadsheet is designed so that when data are entered in

the lumber section, everything common to both lumber and veneer is copied automatically into the veneer input section. These common items are protectedto preserve

this feature, and users must enter all the common input data in the lumber portionof

Figure 4__Spreadsheet example for veneer analysis.

7
Diameter of

PrunedTrees

the spreadsheet even if only a veneer analysis is desired. Veneer prices are for green

veneer and are quoted per thousand square feet on a finished panel size. All prices

must be converted to a 3/8-inch basis. Following is a detailed description of the input

data that are different and must be enteredfrom the veneer analysis screen:

J15__PAB, price of AB veneer in dollars per thousand square feet ($/msf)

J16__PC, price of C veneer ($/msf)

J17__PD,price of D veneer ($/msf)

J18__SABP, cost saving on productionof AB veneer from pruned logs ($/msf of AB

veneer)

Several calculated variables related to log dimension and characteristics differ from

the ones for saw logs becausethe standard log lengthwith trim for veneer is 17 feet

and that for lumber is 16-1/2feet. Followingis a detailed description of the result

variables that are different for this reason:

L7__DSPH,diameter inside bark of the small end of the veneer log at time of pruning

(inches)

L10__DSHV, diameter inside bark of the small end of the veneer log at time of

harvest (inches)

L12__TAPERV, taper of veneer log at time of harvest (inches per foot of length)

L13__JWHV, percentage of the pruned veneer log that is juvenile wood at time of

harvest

L14__CLRV, percentageof the pruned veneer log that is clear wood at time of

harvest

L15__CFV, volume of veneer log at time of harvest (cubic feet)

Output variables unique to the veneer analysis follow:

L16__VRF, veneer recovery factory (squarefeet of 3/8-inchdry trimmed veneer per

cubic foot of log)

04..P6__percentage veneer recovery by grade for the pruned and unpruned log

012, P12__$/msf, value per msf from the pruned and unpruned log

013, P13__SF, volume of veneer (square feet of 3/8-inch dry trimmed) (will always

be the same for pruned and unpruned log)

The PRUNE-SIM users guide (Fight and others 1987b) includes a methodfor estimating average tree diameters when the growth and yield simulator does not provide

a listing of individualtrees. When a growth and yield simulator that provides a stand

table is used, the analysis of pruning can be done with the average prunedtree, or it

can be done for several diameter classes and interpolated values used to get an average increase in present value per pruned tree or per acre.

Average Limb Diameter

on Unpruned Trees

Most growth and yield models do not provide information on the diameter of limbs.

Limb diameters for Douglas-fircan be estimatedfrom equations found in Maguire

and others (1991). Although the data base for those equations is southwest Oregon, 

8
the results were deemed acceptable for use on the Siuslaw National Forest,1 and

 although there is ongoing work, we are not aware of any other source of equations

for predictinglimb diameters that is currently available.

The assumption in the DFPRUNEsoftware is that pruning has no effect on tree

growth or that it is small enough to ignore. Users are referredto O’Hara (1991) for a

discussion and referencesto literature on this issue.

Effect of Crown

Removal on Growth of

Pruned Trees

Macro Feature

in DFPRUNE

Many people will find the DFPRUNEsoftware more useful than any specific analyses

we might publish because the number of regimes for which we can provide analyses

is limited. The program allows users to do sensitivity analysis for the regimes that are

most relevant to their situation; the combinations of prices, regimes, and other assumptions that may be desired in sensitivity analysis will differ. The macros in

DFPRUNE are designed to facilitate making simulations for a large number of

regimes and for doing sensitivity analyses.

One area for which sensitivity analysis may be desired is price premiums for clear

grades of wood products. The problem in deciding what prices to use in the analysis

is that the prices are needed now for a period 30 or more years away. Future prices

are not simply unknown-they are unknowable. We can look at price projections from

various studies of supply and demand for timber and at historicaltrends, but because

we cannot know what future prices will be, we suggest looking at the financial return

from pruning for a range of future prices. The prices used by DFPRUNE are the

prices for lumber and veneer by product grade. The financial return from pruning depends on the difference in price between clear grades and lower grades of products.

In additionto the price difference among AB, C, and D veneers, there is a cost saving

for AB veneer produced from pruned logs. The average number of patches per sheet

of AB veneer from pruned logs will be substantially less than the average number of

patches per sheet of AB veneer from unpruned logs. The cost saving is added to the

price in DFPRUNEto determine the increased returnwith pruning.

Indetermining priorities for pruning, the user may wish to do a sensitivity analysis on

age at time of pruning, age at time of harvest, and site index. A comparison of the

return from pruningfertilized stands with pruning unfertilizedstands also would be

useful. There are some areas where sensitivity analysis can be done only by

changingthe equations in the spreadsheet model; they include the recovery

equations and tree profile equations.

The macros includedin DFPRUNE make doing a set of analyses easier by allowing

the user to put in two sets of prices and simultaneously doing the analysis for lumber

for two sets of prices and for veneer for two sets of prices. All the macros store

summary results and save the input data for further use. When any macro is used,

the prices found in B25..C30 and F25..G27will be moved into the appropriate places

in the lumber and veneer analysis screens and will be used in the analysis. When

macros are used, the prices therefore must be entered at B25..C30 and F25..G27

rather than in the analysis screens. The spreadsheet is set for automatic recalculation ~ ~~~

1 Personal communication. 1991. Stuart Johnston,

silviculturist, Siuslaw National Forest, P.O. Box 1148,

Corvallis,OR 97339

9
of results. If execution is slow, it can be sped up by setting the spreadsheet to

manual recalculation;the macros still will work properly. Because all the macros

contain a provision to print the results, they will not work unless a printer is available

to print the output from a spreadsheet. The printer will use the print setup that

already exists inthe user’s version of the spreadsheet. The macros can be used

without a printer only by removing the print subroutinesfrom the macro

(accomplishedby removing “{ptlum}”and “{ptven}”from the macro and movingthe

remainingitems up to fill in the blank spaces). Worksheet protection must be

disabled to make this change.

A macro is executed by holding down the “Alt” key and pressing the macro name: A,

B, L, M, V, or W. Followingis a detailed description of the macros:

Alt A-Do analysis for both lumber and veneer with twosets of prices for each, print

the results of each analysis, save the summary results of each analysis, and save

the input data

Alt B__Do analysisfor both lumber and veneer with “Hi” prices for each, print the

results of each analysis, save the summary results of each analysis, and save the

input data

Alt L-Do analysis for lumber only with two sets of prices, print the results of each

analysis, save the summary results of each analysis, and save the input data

Alt M-Do analysis for lumber only with “Hi” prices, print the results, save the

summary results, and save the input data

Alt V__Do analysis for veneer only with two sets of prices, print the results of each

analysis, save the summary results of each analysis, and save the input data

Alt W-Do analysis for veneer only with “Hi” prices, print the results, save the

summary results, and save the input data

The section in figure 2 labeled “Summary of lumber results” contains the summary

results from a series of lumber analyses. The column heading abbreviationsfor the

lumber analysis are explained below:

SI-site index

STK-stocking

A1-age at time of pruning

A2-age at time of harvest

TRE-number of trees pruned per acre

SUCC-proportion of trees surviving to harvest

COST__cost of pruning per tree

PRICE__price of C select lumber

$/Mp__value per mbf if pruned

$/Mu-value per mbf if unpruned

FVT__difference in future value per tree between pruned and unprunedtrees

PT1__increase in present value per tree with the first interest rate

10
PA1__increase in present value per acre with the first interest rate

PT2__ increase in present value per tree with the second interest rate

PA2__ increase in present value per acre with the second interest rate

%C__percentage of the pruned log that is clear wood at time of harvest

%SEL__percentage of grade recovery in C and D selects

DBH1__diameter of tree at time of pruning

DBH2__diameter of tree at time of harvest

LDH-average diameter of largest limb in each quadrant of log at time of harvest

JWH__percentage of the log that is juvenile wood at time of harvest

The section in figure 2 labeled “Summary of veneer results” contains the summary

results from a series of veneer analyses. The only column heading abbreviations in

the summary of the veneer analysis that are not the same as those for the lumber 

analysis are:

PRlCE__price of AB veneer

$/Mp__value per msf if pruned

$/Mu__value per msf if unpruned

%AB__percentage of grade recovery in AB veneer

The section in figure 2 labeled“Summary of input data” is where input data used in a

series of analyses will be stored. The row headings are identicalto those found in the

lumber input and results screen, which are defined above.

The data in these summary areas can be erased to clear them to accommodate new

data. Input data can be copied to the input area of the lumber analysis screen to repeat an analysis or do a sensitivity analysis. If data from the results sections are

needed in another location in the spreadsheet for graphing or further analysis, they 

should be moved with the “copy” command. The “move” command should not be

used because the summary section from which the results came will then become

protected and will not accept the results of new analyses.

This spreadsheet program provides a means for simulating the difference between the 

financial returns of pruned and unpruned trees or stands. It is a significant improvement over the PRUNE-SIMprogram, which uses average recovery for unpruned logs

regardless of the specific regime under which pruningwas applied. This program is

easy to use for anyone who has access to a personalcomputer and LOTUS 1-2-3

software.2 This program should be widely applicable to coast Douglas-fir.

There is a conservative bias inthe results of this program because the lumber recovery for pruned logs was basedon processing that was more production orientedthan

grade oriented. A mill oriented to sawing for grade likely would get higher grade recovery from pruned logs than predicted by the model. A bias in the opposite direction 

results because the analysis assumes that all the increase in product value accrues.

The use of trade or firm names in this publicabon is for

reader informatinand does not imply endorsement by the

US. Departmentof Agnculture of any product or service

Summary

11
to the landowner. Although in a reasonably competitive market most of the increase

in value should be bid into the price of stumpage, it would probably be something less

than 100 percent. And there likely are some costs for record keeping that go beyond

the pruningcost dealt with in the program.

Market acceptance of clear wood from prunedtrees is a further source of uncertainty.

Clear wood products from pruned young-growth logs have a different appearance

than clear wood products from old growth. Market resistance to clear wood products

from pruned young growth is likely; the extent is not measurable. Historical experience indicates, however, that as any high-quality resource gets scarcer and more

expensive, people become more willing to use substitutes. Clear wood products from

pruned young growth should be a close substitute for clear wood products from old

growth for many uses; as old-growth clear wood becomes more expensive, the market resistance to young-growth clear wood is likely to diminish.

1 inch = 2.54 centimeters

1foot = 0.305 meter

1cubic foot = 0.028 cubic meter

1 acre = 0.4047 hectare

Cahill, James M.; Snellgrove, Thomas A.; Fahey, Thomas D. 1988. Lumber and

veneer recovery from pruned Douglas-fir. Forest Products Journal. 38(9): 27-32.

Fahey, Thomas D.; Cahill, James M.; Snellgrove, Thomas A.; Heath, Llnda S.

1991. Lumber and veneer recovery from intensively managedyoung-growth

Douglas-fir. Res. Pap. PNW-RP-437. Portland, OR: U.S. Department of

Agriculture, Forest Service, Pacific Northwest Research Station. 25 p.

Fight, Roger D.; Cahlll, James M.; Fahey, Thomas D.; Snellgrove, Thomas A.

1987a. Financial analysis of pruning coast Douglas-fir. Res. Pap. PNW-RP-390.

Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest

Research Station. 17 p.

Fight, Roger D.; Cahill, James M.; Snellgrove, Thomas A.; Fahey, Thomas D.

1987b. PRUNE-SIM users guide. Gen. Tech. Rep. PNW-209. Portland, OR: U.S.

Department of Agriculture, Forest Service, Pacific Northwest Research Station.

Haynes, Rlchard W.; Fight, Roger D. 1992. Price projections for selected grades of

Douglas-fir, coast hem-fir, inland hem-fir, and ponderosa pine lumber. Res. Pap.

PNW-RP-447. Portland, OR:U.S. Department of Agriculture, Forest Service,

PacificNorthwest Research Station. 20 p.

Maguire, Douglas A.; Kershaw, John A., Jr.; Hann, David W. 1991. Predictingthe

effects of silvicultural regime on branch size and crown wood core in Douglas-fir.

Forest Science. 37(5): 1409-1428.

O’Hara, K.L. 1991. A biological justification for pruning in coastal Douglas-fir stands.

Western Journal of Applied Forestry. 6(3): 59-63.

Warren, Debra 0. 1992. Production, prices, employment, and trade in Northwest

forest industries. Resour. Bull. Portland, OR: U.S. Department of Agriculture,

Forest Service, Pacific Northwest Research Station. Quarterly.

Metric Equivalents

Literature Cited

21 p.

12


Fight, Roger D.; Cahll, James M.; Fahey, ThomasD. 1992. DFPRUNE users guide.

Gen Tech. Rep. PNW-GTR-300. Portland, OR. U.S Departmentof Agriculture, Forest

Service, Pacific Northwest Research Station 12 p.

The DFPRUNE spreadsheet program is designed to estimatethe expected financial

return from pruning coast Douglas-fir(Pseudotsugamenziesir (Mirb.)Franco var

menziesii) It is a significant revisionof the PRUNE-SIMprogram The PRUNE-SIM

program was based on the average productrecovery for unpruned logs from a single

stand that receivedfrequent light thinnings The DFPRUNEprogram incorporates new

recovery informationfor unpruned young-growth Douglas-fir and can be used to assess

the economic potentialof pruning for a wide range of management regimes. Product

prices and descriptions of trees at time of pruning and at time of harvest must be

supplied by the user The DFPRUNE program was developed for the Lotus 1-2-3

spreadsheet and shouldwork on versions 2 01 or later.

Keywords: Douglas-fir, pruning, forest productvalue, productrecovery, simulation

The Forest Service of the U.S.. Department of

Agriculture is dedicatedto the principle of multiple

use managementof the Nation'sforest resources

for sustained yields of wood, water, forage, wildlife,

and recreation.Through forestry research,

cooperationwith the States and private forest

owners, and managementof the National Forests

and National Grasslands, it strives__as directed by

Congress-to provide increasinglygreater service

to a growing Nation.

The U.S. Department of Agriculture is an Equal

Opportunity Employer. Applicants for all Department

programswill be given equal considerationwithout

regardto age, race, color, sex, religion, or national

origin.

Pacific Northwest ResearchStation

333 S.W. First Avenue

P.O. Box 3890

Portland, Oregon 97208-3890
U.S. Departmentof Agriculture

Pacific Northwest ResearchStation

333 S.W. First Avenue

P.O. Box 3890

Portland, Oregon 97208

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