United States 

Department of 

VB Merch-Lob: A Growth-and-Yield 

Agriculture Prediction System with a Merchandising 

Forest Service Optimizer for Planted Loblolly Pine in 

the West Gulf Region 

S.J. Chang, R.L. Busby, P.R. Pasala, and D.J. Leduc 

Southern 

Research Station 

Research Paper 

SRS-35 
The Aulhors 

S.J. Ghang, Professor, Louisiana State University, School of Renetvable Natural 

Resources, Baton Rouge. LA 70803: R.L. Busby, Principal Economist. US. 

Department of Agriculture, Forest Service, Southern Research Station, N~L\ 

Orleans. LA 701 13; RR. PasaPa, Gradilate Student. Louisiana State University, 

School of Renetvable Katural Resources, Baton Rouge, LA 70303; and D.J. Leduc, 

Cournputer Specialist, U.S. Department of Agriculture, Forest Service, Southern 

Research Station, Pineville, LA 7 1360. 

The VB kferch-lob Program is available upon request with the understanding that the U.S. Department of Agriculture 

cannot ensul-e its accuracy, completeness. reliability. or suitability for any other purpose than that reported. Neither the 

Southern Research Station nor the authors will be responsible hi- any damages resulting from the use of or inability to 

use this software. The recipient may not assert any proprietary rights thereto nor represent the program to anyone as 

other than a Government-produced computer program. Tlie program risay be obtainled by sending a request to Southern 

Research Station, Rkf T- 10034,li".S.R., 70 1 Loyola Avenue, New Orleans, LA 701 13. 

Use of firm, company, or trade names is for the reader's information and convenience and does not constitute official 

endorsement or approval by the U.S. Department of Agriculture to the exclusion of any other suitable product. 

June 2005 

Southern Research Station 

P-8. Box 2680; 

Asheville, NG 28802 
VB Merch-Lob: A Growth-and-Yield Prediction 

System with a Merchandising Optimizer for Planted 

Loblolly Pine in the West Gu 

S.J. Chang, R.L. Busby, P.R. Pasala, and D.J. Leduc 

Abstract 

A k'iiual Basic computer model that can be used to estinlate the hanest 

value of loblolly pine plaritatiuns in the west gulf reglon is presented. The 

model aces a dynamic programming algorithm to convert stand tables 

predrcted by COMPUTE-P-LOB Into a listing of ieven products that 

maxlmrzei the harvested value of the stand. 

Keywords: Dynamic programming, economics. merchandising. 

optimization, Pinus meih L. 

Summary 

An updated growth-and-yield model with a merchandising 

optimizer can predict volumes and values of thinned or 

unthinned loblolly pine (Pinus tuedn L.). Visual Basic (VB) 

Merch-lob forecasts product volumes and stand values for 

stands partitioned into 1-inch diameter-at-breast-height 

(d.b.h.1 classes at any stage of plantation development from 

ages 10 through 50 years. The minimum initial variables 

necessary to run the program are age, density, site quality, 

minimum and maximum dimensions of products, and 

product prices. The merchandising optimizer converts 

predicted stand tables into an estimated optimum product 

mix with a dynamic programming algorithm that maximizes 

the selling value of the stand. 

Introduction 

An updated computer program, VB Merch-Lob, has been 

developed to estimate the product mix and per-acre stumpage values of planted, thinned or unthinned. loblolly pine. 

VB Merch-Lob is an updated version of the program 

COMPUTE-MERGHLOB (Busby and others 1 990 ). As a 

result the text of this paper closely follows that of 

COMPUTE-SilERCFILOB . This program is written in 

Visual Basic. 

Lobtolly pine is one of the most important commercial tree 

species and also a widely planted southern pine. Managers 

of loblollj pine plantations need accurate and complete 

predictions of product volumes and values to formulate 

management guidelines. For example, they must decide 

whether or not to thin; if the decision is to thin, they must 

decide when, how much, and how often. The effects of 

management actions on the types of products that can be 

produced dictate timing, quantity, and frequency of thinning. 

The stand must be premerchandised. 

Baldwin and Feduccia j 1987) developed a yield prediction 

system for thinned and unthinned loblolly pine plantations 

in the west gulf region. A computer program for this system, 

called Comprehensive Outlook for Managed Pines Using 

Simulated Treatment Experiments for Plantation Loblolly 

Pine (COMPUTE-P-LOB) (Ferguson and Baldwin 19871, 

appeared shortly thereafter. This growth-and-yield prediction system pro\iides both weight and volume yields in a 

standistock table format for the aboveground portion of the 

trees by 1-inch d.b.h. classes for 10- to 50-year-old loblolly 

plantations on cutover sites. Many users want yields to be 

separated into product classes. 

Busby and Ward ( 1989) developed a merchandising optimization routine called MERCHOP for growth-and-yield 

prediction systems. The routine gives users a wide selection 

of product categories and mathematically derives optimum 

product mixes for any yield output. The algorithm divides a 

stand table into six products plus residual wood. Users 

specify product prices, maximum and minimum product 

sizes, minimum harvest volumes, and a factor to account for 

degrade due to form and other defects. 

VB Merch-Lob updates and converts COMPUTEkIERCHLOB (Busby and others 1990) from Fortran to 

Visual Basic. This paper provides essential background 

information about the growth-and-yield prediction system 

from Busby and others (19901, which was based upon the 

growth-and-yield subroutines in Ferguson and Baldwin 

(1987) and the merchandising optimization system from 

Busby and Ward ( 1989). It also provides input requirements 

needed to run the model, an example of output, and a typical 

forest management example to guide system users. 

Program Components 

Growth-and-Yield Subroutines 

The growth-and-yield subroutines are based on measurement data from study plots in unthinned and thinned loblolly 

pine plantations located in east Texas, north and central 
Louisiana, and eastern Mississippi. Plot age (from time of 

planting) ranged from 10 to 45 years: site index (base age 

251, from 40 to 90 feet; and initial planting density. from 

109 to 2,700 trees per acre. The thinning interval for stands 

in the long-term studies was 5 years. and residual densities 

after thinning ranged from 50 to 130 square feet of basal 

area per acre (Baldwin and Feduccia 1987). 

The three-parameter Weibull function (Bailey and Dell 

1973) describes the d.b.h. distribution in a plantation. At any 

time in a stand's development, the model predicts the 

minimum (X, ), quadratic mean (X,,,,). and 93r* percentile 

(1Yq3) stand diameters as functions of the number of trees 

surviving (TS), stand age from planting (A), and dominant 

height (HD) or site index (SI). Algebraic and numerical 

techniques then estimate Weibull parameters (Baldwin and 

Feduccia 1987). Thus, given the prediction of the number of 

trees surviving, the model can partition the total number of 

trees into 1-inch d.b.h. classes, and construct a stand table. 

Growth and Yield sf Unthinned Stands 

When starting with an unthinned stand, the model requires 

A, HD, and TS as input. If HD is not available as input, an 

SI function can predict HD. If the user does not know TS, it 

can be predicted as a function of trees planted per acre (TP), 

A. and HD, or as a function of HD and basal area per acre 

@A). 

Given this initial information, the prediction of X,. Xc,~l,,. and 

X, as functions of WD, TS, and A can describe the current 

stand. The next step estimates the VvTeib~rll parameters and 

produces standistock tables. 

To estimate future stand attributes and future standistock 

table information in unthinned stands, the first step projects 

TS from time A, to time A, using a survival function TS, = f 

(TS,, SI, A,. A,). The SI equation then produces HD, at .A,. 

These values produce estimates of X,. X,,,. and X,? at time 

A,. In the final step, the model yields new Weibull pararneters and derives a new standistock table. 

Stand Attributes After Thinning 

The model determines aspects of the residual stand after 

dlinning by predicting values for X ,.,, X ,,.' Xg3.,, TS,. and 

BA, (""," denotes an after-thinning value). The next step uses 

these values to obtain the 'rYeibull parameters. Data were 

only available for a modified low &inning. Because there 

t\ as a significant difference in the resulting stand between 

the first and subsequent thinnings, Baldwin and Feduecia 

(1 987) developed two separate sets of equations. One 

predicts stand characteristics fo'ollocving the first thinning. 

and the other predicts the residual stand after any subsequent thinning. 

The model can express the target density for each thinning 

as residual stand BA or TS. Batdwin and Feduccia (1987) 

developed the equations fur X ,,,, X ,,,,. X ,,,, as functions of 

the before-thinned values of the predictor variable, HDb, and 

BA,/BA, ("','denotes a before-thinning value). If the chosen 

thinning target is TSd, the model first predicts the value for 

BA, from an equation I-elating TS,/TS, = f (BA, IBA,). 

Growth and Yield of Thinned Stands 

Equations in the thinned stand section of the yield system 

take either predicted or user supplied after-thinning stand 

information at age A,. The model projects these values into 

the future to A, to provide stand table predictions at the new 

stand age. The model predicts the same stand diameter and 

height attributes as elsewhere, and these values yield 

Weibull parameters to describe the new stand. 

The model predicts diameters at a second age ("2") in 

thinned stands (X,,, X,,,,,,. and X93.,j. Equations use initial 

values of the predicted variables X ,,,, X,,d,i. or Xq3.]. 

respectively, and TS,, A,. and A,, Another survival equation, 

TS2 = f (TSI, SI, A,, A,), predicts survival in thinned stands. 

Stand/Stock Table Estimation 

The model generates stand tables for any age by apportioning the total number of surviving trees into I -inch d.b.h. 

classes according to the predicted Weibull distribution for 

that age. Development of a stock table requires a total height 

prediction equation, volume or weight equations. and taper 

equations. We used two height prediction equatiorts-one 

for trees from unthinned stands and one for trees from 

thinned stands. They predict total tree height as a function of 

d.b.h., HD, A, and TS. The volume, volume ratio, weight, 

weight ratio, and taper equations are obtained from Baldwin 

and Feduccia ( 1987). 

Merchandising Routines 

The merchandising routines use dynamic programming to 

find the optimal mix of products that can be cut from stands 

described by the growth-and-yield routines. Users specify 

allowable products, product prices, maximum and minimum 

product sizes. minimum product harvest per-acre voiumes. 

and the percent defect due to poor form and other anornaLies. Six different products can be specified: (1) poles, (2) 

veneer bolts. (3) saw logs, (4) chip-n-saw logs, 15) pulpivood bolts. and (6) chips. Residual wood can account for 

any available wood in the boles of the trees not accounted 

for in the six products. 
The basic problem is to find the highest value of stumpage 

that may be cut from a stand (STDVAL) given certain 

constraints. The optimal solution, S'T;DVAL. has a particular 

combination of associated products (STDWL,). Each 

S7'UWL, volume must meet the minimum product-specific 

harvest value (HARVST,) constraint if the product is to be 

considered in the analysis at all. The solution technique is 

summarized in equation 1 (Busby and Ward 1989): 

subject to: STDVOL, 2 HARVST{, 

where 

VALL"E, = per-unit value of product i 

All other variables are as previously defined. 

Busby and Ward (1989) give details on how this problem is 

solved. 

Program Description 

The model allocates the entire bole of each tree to one or 

more of the six product categories or to residual wood. 

The units of measurement for the products are cords, tons, 

and board feet (in Doyle, Scribner, or International 114- 

inch). depending upon the type of product. 

A three-step process calculates cords. The first step calculates the total cubic-foot volume of the solid wood inside 

bark (i.b.) for each log using COMPUTE-P-LOB routines. 

The equation for unthinned stands (Baldwin and Feduccia 

1987) is: 

where 

TV,, = the total stem volurne (cubic feet, i.b.) 

D = the d.b.h. 

H = total tree height feet) 

The equation for thinned stands is: 

where 

all variables are as previously defined. 

The second step finds the cubic-foot volume of any particular log. Baldwin and Feduccia (1987) provide coefficients 

for an equation to estimate the ratio of total merchantable 

volume, to any top diameter, to the total volume in the tree. 

The equation for unthinned stands is: 

where 

kfVi, = the merchantable volume i.b. 

d = the upper stem diameter limit (outside bark, in inches) 

The equation for thinned stands is: 

Mvlh - exp [ -2.177444 [ D5.1 

5.239462 

14077 I] 

TY, 

where 

All \ ariables are as previously defined. 

The equation calculates the cubic-hot volume for any log 

by finding MV,,ITI/:, to the top and bottom. The difference 

between the two ratios represents the volume of that log. 

Total cubic-foot volume is the product of multiplying the 

ratio by the total volume in the tree, which was calculated in 

equation 2 for an unthinned stand, or by using equation 3 for 

the thinned case. 

The third step in calculating cord volume is to divide the 

resulting cubic-foot volume by the appropriate cubic-footper-cord ratio (CUflCD), which is the number of cubic feet 

of solid wood per cord. The default value of GUFTCD is 76, 

which is the conversion factor for straight and smooth 

loblolly pine that has midlength outside bark diameters of < 

6 inches as reported in Koch ( 1972). 

A two-step process calculates tons. First, the green weight of 

the total stem, including bark (EW(,,), comes from the 

equation in Baldwin and Feduccia 4 1987): 
where 

A = the age from planting 

All variables are as previously defined. 

The second step is to find the weight of the particular tog. 

Baldwin and Feduccia (1 987) prokide coe"iicients for 

equations to estimate the ratio of merchantable green weight 

outside bark (iMGIVo,) to any top diameter and TGW(,,. The 

equation for unthinned stands is: 

where 

All \variables are as previously defined. 

The equation for thinned stands is: 

All variables are as previously defined. 

The total ~veight in pounds for any log is calculated by 

finding MGW,,, /TG!V(,/?, first to the top and then to the 

bottom of the log being examined. The difference between 

the rtvo ratios is the ratio represented by that log, hlultiplying that Iog's ratio b) the total ir~eight of the tree (calculated 

in equatl0114j yields total log weight. Dividin~g total log 

tuelght bj 2,080 expresses the result in tons. 

Doyle and Scribner ~siiuimec in board feet are calculated 

with the formulae from Grosenbaugh (1 952): 

DlB =. the diarneter inside bark at the top end of the log 

L = the lertgth of the log 

International li4-inch volumes in board feet are calculated 

using the formula from Koch 11 973): 

\v here 

All variables are as previously defined. 

The model then requires price and product dimensions. The 

user must specify unit prices by product, minimum and 

maximum top-end diameters, minimum and maximum piece 

lengths, the piece-length increment, and allowance for trim. 

These inputs allow the user to specify the size and value for 

each product. For example, the user could say that poles 

must have a top-end diameter between 4 and 10 inches and 

be between 40 and 70 kct in length. The user is asked to 

define only possible products. The model solves the 

problem of finding the best product mix. 

Two problems arise when attempting to estimate the best 

product mix: ( I) the growth-a11d-yield model does not 

provide form and disease product degrade information, and 

(3) small quantities of even high-valued products may be 

too expensive to sort out and sell. Form and disease product 

degrade may be modeled by including the input variable 

DEFECT defined as the percentage of properly sized trees 

illcapable of making a particular product. For example, not 

all; trees 40 feet tall to a 6-inch top are suitable for pole 

production because some may hate bad form or a defect that 

precludes such use. If 60 percent of all properly sized trees 

have defects, DEFECT cvould be set to 60. 

The v~~~nd problem, the high price of sorting and selling 

small quantities of even high-valued products, is sotked by 

including the HARkWST variable. The user sets the minimum 

harvest volume required in a stand if that product is going to 

be produced at all IHAR'G'ST), and any solution to the model 

must meet that constraint. For exampie, the user ma) 

specify that a minimum of 1,000 board feet per acre of 

sa~vtimber logs must be produced. 
Program Operation Literature Cited 

The VB Merch-Lob Program is currently available in VB 

for use on the Microsoft Windows -based systems. Copies of 

the executable version of the program are available from the 

authors. The appendix provides a detailed example of 

executing the model. 

Discussion and Conclusions 

Diameter distribution and individual-tree-based growth-andyield prediction systems will each provide stand and stock 

table output. Some, such as COMPUTE-P-LOB, include 

weight as well as volume yields. These features can help a 

forest manager predict future product yield. However, 

economic and product specification information are also 

required to merchandise a stand effectively. Forest managers 

have needed a method to estimate the economic impact of 

proposed management practices (such as thinning), whic1.a 

will not only alter total volume and weight yields, but also 

alter the size and shape of tree boles and the ratio of 

branchwood to bolewood. Thinning changes the product 

mix of a stand that will ultimately be harvested. VB MerchLob meets some of these management needs. 

VB Merch-lob provides two tables at the output stage- a 

product yield table of specified product possibilities and a 

value table predicting monetary amounts for the products. 

The model describes the exact combination of products that 

will yield the highest value. These represent the highest 

value solutions, subject to the constraints imposed by the 

users. Using model predictions, a manager can make profits 

marketing wood products using plantation loblolly pine in 

the west gulf region. 

Barley, Robert L.; Deli. T.R. 1973. Quanr~ljilng diameter disirrbut~uns with 

the Weibull function. Forest Sc~ence. 19: 97- 103. 

Bald\vzn, V.C.. Jr. 1987. Green and dq-tveight equatrons for above-ground 

components of planted loblolly pine trees In the west gulf region, 

Southem Journal of Applied Forestry. 1 1 : 7 12-2 18. 

Batdwin, V.C., Jr.; Rduccta, D.P. 1987. Loblolly pine grotvth and yield 

prediction for managed west gulf region plantations. Res. Pap. SO-235. 

New Orleans: U.S. Department of Agrrcuiture, Forest Servrce, Southern 

Forest Experiment Station. 32 p. 

Busby, Rodney L.; Ward, Keith B. 1989. MERCHOP: a dynamic 

programming model for estimating the harvest value of unthinned 

loblolly and slash plne plantations. Res. Pap. SO-254. New Orleans: 

U.S. Deparrnlent of Agrrcutture, Forest Service, Southern Forest 

Experiment Station. 19 p. 

Busby, R.L.; Ward, K.B.; Baldrvin. V.C., Jr. 1990. 

COMPUTE-MERCHLOB: a growth and yield prediction system with a 

merchandising optimtzer for planted loblolly pine in the west gulf 

region. Res. Pap. SO-255. New Orleans: U.S. Department of Agriculture, Forest Service, Southern Forest Experiment Station. 27 p. 

Ferguson, R.R.: Baldwin, V.C., Jr. 1987. Comprehensive outlook for 

rnanaged pine using simulated treatment experiments - planted loblolly 

pine (COMPUTE-P-LOB): a users guide. Res. Pap. SO-241. New 

Orleans: U.S. Department of Agriculture, Forest Service, Southern 

Forest Expenment Station. 64 p. 

Grosenbaugh, L.R. 1952. Shoncuts for cruisers and scalers. Occas. Pap. 

126. New Orleans: U.S. Department of Agriculture, Forest Service. 

Southern Forest Experiment Station. 24 p. 

Koch, Peter. 1972. Utilization of the southern pines. Agric. Handb. 420. 

Washington, DC: U.S. Department of Agriculture. 1.663 p. 2 vol. 
Appendix 

Input Specifications for VB Merch-Lob 

Input to run the model is entered on four forms. The first 

three contain inputs to run the growth-and-yield routines, 

and the four*th contains product information needed by the 

merchandising routines. Output from the model goes to a 

file or a printer. 

Growth-and-yield data-The growth-and-yield data needed 

to run VB Merch-Lob are the same variables required to run 

COMPUTE-P-LOB. 

Initially, VB Merch-Lob requires the user to provide the age 

of the stand (A), an indication of site quality, and a measure 

of stand density. There are two ways to indicate site quality. 

The user may supply the mean dominant and codominant 

height of the stand (HD) to calculate site index (ST). 

Alternatively, the user may supply the stand's site index and 

base age for the site index measure (BSAG). Note the 

BSAG must be either 25 or 50 years. If the user has estimates of both HD and ST, HD is preferred, because the 

growth-and-yield model COMPUTE-P-LOB would ignore 

SI and BSAG if both measures of site productivity were 

supplied. The user must also supply a measure of stand 

density by choosing to provide either the basal area (BA), 

trees surviving at the starting stand age (TS), or the number 

of trees planted (TP). If the user has more than one measure 

of stand density, we advise use of the same priorities used in 

COMPUTE-P-LOB, if all three measures are provided: (I) 

TS, (2) BA, and finally (3) TP (fig. A. I ). 

Next, the user is asked: Has the stand been thinned before? 

If it has, the user must provide the number of previous 

thinnings, the age of the last thinning. and either the residual 

BA or the number of trees per acre remaining after the last 

thinning (fig. A. 1). The title of the run to be printed in the 

output is entered on the second screen. Users also may 

provide the number of thinnings desired with this run and 

the thinning method as residual BA or residual number of 

trees. Note that the model allows the user to specify up to 

seven different thinnings. The remaining entries on that 

fosrn are the ages of thinnings and their corresponding target 

values (fig. A.2). The model will automatically print both 

prethinning and post thinning tables, as well as the cut table 

for each thinning. 

The third form (fig. A.3) allows the user to specify ages, 

other than thinning ages, for which the model should 

generate output. The user supplies the number of tables 

desired and the ages for which the information is required. A 

single run may produce a maximurn of 15 tables. Because 

the model will generate a prethinning table and postthinning 

table at each thinning, these will be subtracted from the total 

of 15 tables. 

The fourth form (fig. A.4) gathers information for the 

model's economic subroutines. The first listed variable is 

product name. The user may analyze up to six products by 

marking a "Y" in the "Produce" column; marking an "N" 

age i betir~eer~ 10 mci 511) 

ant hedt TI feet or site mriesr md base @ Site hdex r)~ mr~ant md Cc drj~mialt height 

site u~dez (Iiefazlt ::al~i~. 1s 251 

Ezsdakea C l.Tc #jftree:: pixited 

tmd bern tkm1e4 before 

cr ofprem.us thx~axz beGrc Be :tat rsf tius 11m 

F~gure A. l -Input ~nfc>matron is entered for the existir~g \land to be modeled. 
be dorie d~mg the m ( 0 - 7 ) 

area (or) Tree~i'acr~ for first 

dud basal area [or) Treesiacre for second tk~- 

Target resldutll basal area jar) Treesiacre for fourth hg 

(or) Treesjacre fir 

for) Treesiacre for seventh 

Figure A.2-The user supplies a title to the run and indicates the number and type of thinnings to be modeled. 

ested exclu&x those at tkq ages 

Age for fo~xth requested table 

Age for fifth requested table 

Age for sdi req~~ested table 

P,ee for seven& requested table 

hth requested table 

Figure A.3-The user then specifies the years desired for a stand stable. Stand tables will automatically be 

produced for years in which a th~nning occurs. 
Figure A.3-The user the11 pro\ ides kej econornrc and prod~~ct information needed to nierchandise the itand. 

means that the product will not be considered. The user must 

choose "Y"' or ""N" for each. 

Five scale measures are possible in the model. They are: (I) 

cords (61, (3) Doyle MBF (thousand board feet) ("D), (3) 

International 1;4-inch MBF (I), (4) Scribner 1MBF (S), or (5) 

tons (T). Users express their choice by placing the proper 

letter in the ""Sale" column. The following are default 

options and allotltied output measurement scales for each 

product: 

Model Measurement scale 

Product default allo~ved 

Poles Scribner Scribner, Doyle, or 

ln ternativnal 

Veneer bolts Scribner Scribner, Doyle, 

International, or cords 

Sawtimber Scnhner Scribner, Doyle, or 

International 

Chip-n-sakv logs Cords Seribner, Doyle, 

International, or curds 

Puipwosd bolts Cords Cords or tons 

Chips Cords Cords czr tons 

The user marks a price per unit for each product in column 

"'Price'": note, residual wood is not priced. The user then 

provides the minimum and maximum scaaing diameters (in 

inches) for product I' in the next tt~o columns. If the log 

segment's top-end diameter is within the range of the 

minimum and n~axinlurn scaling diameter, then that product 

is considered for production, Note the ranges of scaling 

diameter-s normally ~;c;ill overlap. This aljows for the same 

diameter log to be used for more than one product. The exact 

combination of products depends on which combination will 

yield the highest value. 

The minimum. maximum. and increment of log lengths for 

each product examined are marked in the next three columns, respectively. 

The final input I-equirement for the product dimensions is 

"Trim, , which is the trim allowance for each product. 

The value for the stage interval used in the dynalnic programming subroutines is 0.25 foot. Therefore, the total 

length of all logs, including trim allowance, must be a 

rnultiple of the stage interval. The model will print an error 

message if this condition is violated. 

A log with dimensions sufficient for a particular product 

might have certain defects that preclude such use. The user 

assigns a value for DEFECT!, an eslimate of the defect in the 

product i-sized trees, in coiumn ""Defect"' for each productspecific Line. If a log can provide product i, then all products 

14-1 are assumed from that log. Hence, as one Inputs the data, 

DEFECT: must be 5 DEFECTI+# for 41 products. 

If the user does not allocate part of the bole of the tree to one 

of the firit six products. the model autornaticaliy produces 

residual ~vooci. 

The next required input is HARIrS'Z',. This is the &imm 

stand \oIunte of a particular product. The units of measure 

for this variable are the same as for SCALE,. Input values 

should be placed in eolun~n ""Harvest'". Figure A.5 shorvs an 

example of the output of a run of the model. 
-----------,---------------- -"-----a--m-----A------4--------&---- --- -- ------~--a-~----~---&*--d---4-~-&-d-------~------------------~a-~---*---~~~-~~~~-----~~--d-- 

Test of VB Mereh-Lob -e----m----------d-.. ------------------- ----A - -- ----------------*--------- ---- ...---------- --a------------------ ------a=- -.."...----."*-- --"----------------c--d--------------4----d-------------m"- " 

Visual Basic Version Of COMPUTEJfERCWLOB 

Deve l sped by : 

Br- Sun Cosegh Chang and Prasanth R-PasaPa 

School of Renewable Natural Wescxdrces 

Louisiana State University 

Baton Rouge, LA 90863 

Br,Rsdney t, Busby 

USDA Forest Service, Southern Research Statron 

New Orleans, LA 70113 

Based m: 

Compu t aJ4erehiah dde*ireloped by 

Busby, Ward, acd Baldwin (1990) 

USCA Forest Service, Southern Research Starion 

Research Paper 58-225 ----- -- -----*-d-----d------------------- ----- *- - ---*---...?---,. "*-- ---a ?- --"-- *---- --- ....-."- "--"--"".--------------a a- *--*------*--<- -"-- ---- ---<----- a&------- -- 

M I a 

C I3 I3 I3 El I4 0 

P A P A MI 141 W M C L M I? H 

R T R S IA AA IL A L % R 0 D iEX 

@ & e us E NN XH "&It X & E E w u NRR 

13 2 D R:C a v r~ IE IN I N M M T A P IAY 

u o u A P MT MT MG 14 G G E R M E BI B E 

fz I3 r; B$L CEI U& C& GT U T T N I C C :J IA S 

T Y E GE ea~ MR MR MH 13 13 WT I< E Aq MET 

gr)l es N S 205,00 C4.0C 19,00 93S,C3 09C=QO 8C5,OO C!Qb,24 075,GO C09,93 

veneer S 158-00 &8,00 24-00 008.03 908-00 08C.90 OOC,25 050,60 $09.0.3 

sawtisber V S %48,06 39,50 %8,QO Q08a00 016.00 002,QO i330,%5 020,00 OCO,CC 

ch5p-n-saw V C B34,i7 96,OQ 12,OQ 006.09 816.9C 002-30 Q60,25 020,00 OB0,CO 

pufp#aad Y C CI4,WY 03-50 12-00 005*00 005.00 OOO-CB 000.00 9OO,QO 005-30 C~I.~S u c GOI~OO oem m,m tee-as oos.as ooe,os caa-oo cooeoo coo,c~ 

residual ? 1 000,OG 08,60 $0.00 600.25 C80,25 COQ,OO 066,OC Q00,00 OCQ,bO 

3 - Doyle Scale(MBFT 

S - Scribner Scale (tBPI 

X - ~ctexnar~onai -1/4 Scale 

Other Wadel Parameters: 

cubic faat to cord ratio = 7& 

stags intervai =0,25 

stump height = 0.5 

Initial Stand Parmeters are : 

Age -- 15 

H = 044.43 

91 = 65 

Bsag = 25 

2"s = SO0 

Ba =: 0 

Tp =o 

previous Lhins = p; 

Ipthrn -= C 

Itage = hi 

1 1- a 

Itpa --- 0 
LOBLQLLY PINE 

Before thinning info 

GROW ING 

%=SONS DBH 

SINCE CLASS 

EST 

15 

02 

33 

04 

05 

as 

07 

08 

09 

10 

GROWING 

SEiSONS DOH 

SIMCE CLASS 

EST 

25 

3 2 

03 

04 

05 

86 

07 

88 

09 

10 

Site index = 60 

Base age = 25 

Basal area = 11Qe51 

STm$ ------------------ vslue------------ 

PER saweimb C-N-S pulpwood ships 

AeRe (mes) acoam (~0~3) ~COWDI 

STmS ------------------- va%ue-----------.---.- 

PER sawtimb C-N-S pulpwood chips 

ACRE ($1 r $ I ($1 ($1 

The total value of the harvest from this stand 

is S357*93* 

I continued 1 

Figure A.5-Example output of VB Merch-Lob (continued to next page). 
GROW 9NG 

SEXSONS DSH 

SINCE CLASS 

EST 

15 

03 

04 

05 

06 

63 

08 

09 

10 

GROWING 

%=SONS DBH 

SINCE CLASS 

EST 

15 

03 

04 

a5 

06 

0s" 

08 

09 

20 

LOBLOILLY PIME 

Residual stand -- after thinning 

Site index = 60 

Base age .= 25 

Basal area = 80.00 

STmfS ------------------ vslme------------- 

PER sawti* C-H-S pulp~asd chips 

ACRE (=PSI (CORD! (CORD1 (CORD] 

sTms --4---------------- va4ue-- 

PER sw&ti& C-M-S pulpwasd 

~$1 ($1 ($1 chips 

(S 1 

The total value sf the harvest from this stand 

is $293.51, 

continued 

Figure A.5-Example output of VB Merch-Lob (continued to next page). 
CROW IEJC 

SEASONS DBW 

SINCE GLASS 

EST 

15 

oa 

03 

04 

05 

06 

07 

08 

09 

10 

LQBLOLLY PIME! 

Stand component removed by thinning 

Site index = 68 

Bass age = 25 

Basal area = 29.51 

CROW1 EBG STms ------------------- value------------.- 

SEASONS DBM PER sawti& C-N--S pulpwood chips 

SINCE CLASS ACRE ($1 ($1 ($1 ($1 

EST 

15 

02 602 000-00 080,09 000.00 000,08 

83 009 000,OO 000,OO 000,OO 900,06 

04 024 060,OO 000,OO 000.60 000-36 

05 034 000-08 00Q,00 003-34 000,48 

06 040 000,00 008,00 019-37 G60,32 

07 827 008,OO 680,OO 020.54 000.18 

08 012 008.00 014,Qd 007-39 000-04 

09 664 OQO,OO 008.45 002.16 000.01 

10 082 000,OO 003-23 000.43 000,OO 

155 OQ00,OB 0025-44 0057,23 6Q8$,4S 

The total value oE the harvest from this stand is 

$84,42. 

Figure A.5-Example output of VB hlerch-Lob (continued to next page). 
GRGWING 

SEASONS 3BH 

SINCE CLASS 

EST 

20 

04 

05 

06 

07 

08 

09 

10 

11 

12 

13 

STEMS - 2ER 

ACRE 

LOBLOLLY PIME 

No thinning this year 

Site index = 60 

Base age = 225 

Basal. area = 107,37 

".-----<----------- voi~~e---- 

sawtinib C-N-S pulpwood 

WBPS I CORD) (cowl chips (CORD B 

GR-GiaJ 1 pJG VJa ice- - - - - - - - - - - - - - 

SmSOXS DBH PER sw~tinb G-N-S pulpdood chips 

SINCE CLASS ACRE ($1 ($1 is) (5) 

EST 

26 

C4 004 COO-OO 003-00 ObB.00 000-09 

05 024 000.00 006-06 005-54 09C-29 

06 048 Q30,BO 000-90 025-37 000,4d 

07 867 000,OO 000,OO 056.69 606.58 

08 040 060,OO 083,98 047,89 000,50 

09 054 OG0.00 146.88 C30-94 000-24 

1Q 030 006-00 $S5,P4 Q%4,52 000,$6 

11 012 000,OO 062,02 005,539 000-03 

12 033 015,$8 012-70 Q01,38 000.02 

13 Go1 008-75 304,;k 900-52 000.QO ---------------------------------------- 

315 0023*93 0423-64 0288,85 0902.36 

The tocal value of the harvest from this stacd 

is $638.79, 

Flpure A.5-Example otirlzur of YB Merch-Lob iconrmued to next page). 
GROWING ST&%S - SSASQHS DBH PER 

SINCE CLASS ACRE 

EST 

25 

04 002 

05 011 

06 026 

0's 042 

08 054 

09 057 

18 045 

11 029 

12 014 

13 005 

14 802 

LBBLOLLY PINE 

No thinning this year 

Site index = 60 

Base age = 25 

Basal area = 124-57 

--------- vJ(-J~~~-"------------ 

C-N-S pulpwood chips 

(CORD) (CORD) (CORD) 

GWOSJ 1 FJG STBgS ------------------- value------------- 

SEASONS DBM PER sawti& C-N-S pulpwood chips 

SINCE CLASS ACRE ($1 ($1 ($1 ($1 

EST 

25 

84 002 000-00 Q80,60 000,OO 806-03 

05 011 000,QO 080,60 002-61 000-15 

06 026 @00,00 Q00,00 014.08 009.30 

07 04% 000,00 000,00 040-57 000.27 

08 054 800.00 07%,88 042-73 400,%4 

89 057 000,OO 168-28 035,23 008,36 

10 045 980.00 192,56 027,55 000-96 

12 029 080,OO 168,21 815,91 080.11 

22 814 04%,58 069,09 008, %I 000.03 

13 005 048,57 022.72 603,26 00Q,01 

14 002 029,32 008.45 001-32 000-01 ---------------------------------------- 

287 0249,48 0703,12 0191,28 0801.66 

The total value sf the harvest from this stand 

is $1,045,54, 

continued 

Figure A.5-Example output of' VB Merch-lob (continued to next page). 
GROW I NG 

SI3ASBNS DBH 

SINCE CLASS 

EST 

30 

05 

06 

87 

68 

09 

10 

3.1 

1% 

I3 

I4 

15 

16 

LBBLOLLY PIW 

No thinning this year 

Site index = 60 

Base age = 25 

Basal area = 138-46 

qTafS - - - - - - - - - - - - - - - - - VO~W*~ - - - - - - - - - - - - - 

PER sawtiimb G-N-S pulpwood chips 

ACRE JMBFS) (CORD) (CORD) (CORD) 

GROW I NG STEMS 

SIEASONS EBB PER 

SINCE CLASS ACRE 

EST 

30 

05 C05 

06 024 

137 026 

08 039 

09 046 

90 045 

11 037 

12 024 

13 013 

14 005 

15 9402 

16 001 

------ 

257 

------------------ -value - - - a - - - - - - - - - sawtimb C-N-S pulp~~aod chips 

($1 ($1 ($1 ($1 

The total value of the harvest from this stand 

is $1,488,10. 

Figure A.5 -Exa~npie ourput of VB Merch-Lob. 
1 Chang, S.J.; Busby, R.L.; Pasala, P.R.; Leduc, D.J. 2005. VH Merch-Lob: a 

growth-and-yield pl-ediction system with a merchandising optimizer for the 

planted loblollj pine in the west gulf region. Res. Pap. SRS-35. Asheville, 

NC: U.S. Department of Agriculture, Forest Service, Southern Research 

Station. 15 p. 

A Visual Basic computer model that can be used to estimate the harvest value of 

loblolly pine plantations in the west gulf region is presented. The model uses a 

dynamic programming algorithm to convert stand tables predicted by 

COIGPUTE-P-LOB into a listing of seven products that maximizes the harvested value of the star~d. 

Keywords: Dynamic programming, economies, merciiandising, optimization, 

Pinzls twda L. 
The Forest Service, United States Department of 

Agriculture (USDA), is dedicated to the principle of 

multiple use management of the Nation's forest resources 

for &stained 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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on the basis of race, color, national origin, sex, religion, age, 

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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 

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of Civil Rights, Room 326-W, Whitten Building, 1400 

Independence Avenue, SW, Washington, D.C. 20250-9410 or call 

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

provider and employer.