SORTIE-ND
Software for spatially-explicit simulation of forest dynamics

# Merchantable Timber Value

This behavior calculates the value of merchantable timber.

### Parameters for this behavior

Parameter nameDescription
Merchantable Timber Value Form ClassThe form class of the species. Valid values are 78, 79, 80, 81, 84, and 85.
Merchantable Timber Value Price / 1000 Board FeetThe price per thousand board feet for each species. The currency used doesn't matter.

### How it works

The value for each tree is calculated by finding out its volume in board feet, and multiplying that by the price for its species. The price is held in the Merchantable Timber Value Price / 1000 Board Feet parameter. The currency used doesn't matter. The tree's final value is placed in a tree data member called "Merchantable Value". The total value for each species is saved in a grid called Merchantable Timber Value. You can save these values in a detailed output file for analysis.

The volume of merchantable timber in a tree depends on its size and form class. These control how many 16-foot logs there are in a tree, and how many board feet of timber (assuming 0.25-inch thickness) those logs can create. The form class is entered in the Merchantable Timber Value Form Class parameter.

The behavior begins by finding out how many 16-foot logs the tree can provide in its bole. The base of the bole is the top of the cut stump; the top of the bole is the merchantable height. This behavior defines the merchantable height as the height at which the trunk diameter inside the bark tapers to 60% of DBH. The behavior tries fitting in as many 16-foot logs as possible before the 60% taper occurs. The amount of taper at the top of the first 16-foot log is established by the tree's form class. A species's form class is the percentage of DBH to which the bole has tapered at the top of the first 16-foot log.

Then the behavior determines how many more logs the tree contains. The amount of taper at the top of the first 16-foot log is subtracted from the DBH, to see how much taper is left before the 60% merchantable-height diameter is reached. There is no formula that establishes clearly how many logs will fit; the behavior uses a trial-and-error approach taken from Messavage and Girard, 1956. This paper includes the table below for upper-log taper for trees of various DBH and bole heights. The behavior uses this table to determine the maximum number of logs it can fit into the taper available.

Trees below 10 inches of DBH contain no merchantable timber and have a value of zero. Trees greater than 40 inches of DBH are treated like 40-inch trees.

Once the behavior figures out how many 16-foot logs a tree contains, it uses another set of tables, based on form class, to determine how many board-feet of timber the tree contains. These tables are also from Messavage and Girard, 1956, and are shown below.

Average upper-log taper (inches) in 16-foot logs
DBH (in)2-log tree3-log tree4-log tree5-log tree6-log tree
2d log2d log3d log2d log3d log4th log2d log3d log4th log5th log2d log3d log4th log5th log6th log
101.41.21.4------------------------------------
121.61.31.51.11.41.9---------------------------
141.71.41.61.21.52---------------------------
161.91.51.71.21.62.1---------------------------
1821.61.81.31.72.2---------------------------
202.11.71.91.41.82.41.11.62.22.9---------------
222.21.821.422.51.11.72.32.9---------------
242.31.82.21.52.22.61.11.82.43.1---------------
262.41.92.31.52.32.71.11.92.53.2---------------
282.51.92.51.62.42.81.21.92.63.30.91.42.13.24.4
302.622.61.72.531.222.73.50.91.42.13.24.5
322.722.71.72.53.11.22.12.93.711.42.13.24.6
342.82.12.71.82.53.31.32.133.811.42.23.34.7
362.82.12.81.82.63.41.32.233.91.11.52.23.34.9
382.92.12.81.92.63.41.32.23.13.91.11.52.33.45.1
402.92.22.81.92.73.41.42.33.241.21.52.43.55.3

Volume (board feet) by number of usable 16 foot logs
Form Class 78:
DBH (inches)1 log2 logs3 logs4 logs5 logs6 logs
10365973---------
11467696---------
125692120137------
1367112147168------
1478132174200------
1592156208242------
16106180241285------
17121206278330------
18136233314374------
19154264358427------
20171296401480542---
21191332450542616---
22211368500603691---
23231404552663714---
24251441605723782---
25275484665800865---
262995287258771,021---
273235727889521,111---
283476168501,0271,2011,358
293756679201,1121,3081,488
304037189911,1981,4151,619
314327721,0701,2991,5261,754
324628261,1491,4001,6371,888
334928801,2261,4951,7502,026
345219341,3041,5901,8642,163
355559981,3941,7022,0002,312
365891,0631,4851,8142,1352,461
376221,1241,5781,9262,2722,616
386561,1861,6702,0382,4102,771
396941,2581,7692,1662,5522,937
407311,3291,8682,2942,6933,103

Form Class 79:
DBH (inches)1 log2 logs3 logs4 logs5 logs6 logs
10386177---------
114878100---------
125896124141------
1370117153176------
1482138182211------
1595160214252------
16108183246292------
17124212286340------
18140240325388------
19158272370442------
20176305414496561---
21196342464558636---
22216378514621710---
23238418571687792---
24260458628753875---
25282499685826960---
263055407428991,046---
273315888109801,144---
283576358771,0611,2421,404
293856869481,1481,3501,537
304137371,0201,2351,4581,670
314447921,1001,3381,5721,808
324748481,1811,4401,6851,945
335069071,2651,5441,8082,094
345389661,3491,6471,9322,244
355701,0261,4351,7542,0002,384
366021,0871,5211,8602,1892,525
376381,1541,6201,9802,3382,694
386741,2201,7202,1012,4882,862
397121,2921,8222,2322,6323,031
407501,3651,9232,3622,7753,200

Form Class 80:
DBH (inches)1 log2 logs3 logs4 logs5 logs6 logs
10396380---------
114980104---------
125998127146------
1371120156181------
1483141186216------
1598166221260------
16112190256305------
17128219296354------
18144248336402------
19162281382457------
20181314427512580---
21201350478575656---
22221387528638732---
23244428586706816---
24266469644773899---
25290514706852992---
263155587679311,086---
273416068361,0141,185---
283676549041,0961,2841,453
293967069771,1841,3941,588
304247581,0501,2721,5031,723
314548141,1321,3761,6181,862
324858701,2131,4801,7332,001
335189301,2981,5861,8582,152
345509891,3831,6911,9842,304
355851,0551,4771,8062,1242,458
366201,1211,5711,9222,2642,612
376561,1881,6722,0442,4162,783
386931,2561,7722,1672,5682,954
397321,3301,8742,3002,7143,127
407701,4031,9772,4322,8603,300

Form Class 81:
DBH (inches)1 log2 logs3 logs4 logs5 logs6 logs
10406582---------
115082106---------
1260100130150------
1372122160186------
1485144190221------
15100170228268------
16115197265316------
17132226306366------
18148256346415------
19166290392471------
20185323439527598---
21206360492592676---
22227398544656754---
23250439602724838---
24272480659791923---
252985287268771,024---
263245757939631,124---
273516248631,0471,226---
283786749331,1311,3271,502
294067261,0061,2201,4381,640
304357791,0801,3101,5491,777
314668361,1621,4161,6661,918
324978921,2451,5221,7842,059
335309531,3321,6281,9102,214
345631,0141,4191,7342,0372,368
356001,0841,5181,8592,1882,534
366371,1541,6181,9842,3382,700
376741,2231,7212,1092,4942,874
387121,2921,8242,2342,6493,049
397511,3661,9282,3682,7963,224
407901,4412,0322,5022,9443,399

Form Class 84:
DBH (inches)1 log2 logs3 logs4 logs5 logs6 logs
10437191---------
115491118---------
1266111145168------
1380135178208------
1493159212248------
15108185249295------
16123211286342------
17142244332398------
18160277377453------
19180314428524------
20200351479576657---
21223392537649744---
22246434595722830---
23271480660798925---
242965257248731,020---
253225727909581,118---
263476198551,0421,217---
273766739321,1361,331---
284067271,0101,2301,4451,636
294387861,0921,3301,5691,790
304708441,1731,4291,6931,943
315049071,2651,5461,8232,101
325389701,3571,6641,9532,259
335741,0371,4531,7822,0962,431
346111,1041,5491,9012,2402,603
356471,1731,6482,0232,3872,766
366831,2421,7462,1452,5342,929
377241,3181,8592,2842,7063,123
387651,3931,9722,4222,8773,317
398081,4762,0882,5703,0423,512
408511,5582,2032,7193,2083,706

Form Class 85:
DBH (inches)1 log2 logs3 logs4 logs5 logs6 logs
10457494---------
115694122---------
1268114150173------
1382138184214------
1495163217254------
15111191257304------
16127219297355------
17146252342412------
18164285388468------
19184322440531------
20205360492594678---
21228402550667765---
22251444609740852---
23276490675818950---
243025377418951,047---
253305888129861,153---
263576388821,0761,259---
273876939611,1721,374---
284177451,0401,2671,4901,689
294488071,1221,3681,6161,844
304818661,2051,4691,7411,999
315169301,2981,5881,8742,160
325509931,3911,7062,0062,321
335871,0611,4881,8272,1502,495
346241,1291,5861,9482,2942,669
356631,2041,6922,0802,4542,846
367021,2781,7972,2122,6143,022
377441,3551,9122,3522,7883,219
387851,4322,0272,4932,9623,416
398281,5152,1442,6443,1303,614
408721,5982,2602,7953,2983,813

### How to apply it

Apply this behavior to saplings, adults, or snags of any species. This behavior does not automatically create output. Once you have added this behavior to your run, the Detailed output setup window for trees will have a tree data member called "Merchantable Value". Add this to your detailed output file to output volume in cubic feet. You can also use the Detailed output grid setup window to save the data members in the Merchantable Timber Value grid, which contains the total value for each species. You can then view the contents of this grid as a table using SORTIE's data visualization system.