Tree Volume
Mesavage and Girard Tree Volume equations
These equations were developed by H. V. Wiant, Jr. and published in 1986. They are to produce the number similar to those published in the Mesavage and Girard, 1946.
International 1/4" boardfeet
$ a = (-13.35212 + 9.58615 L + 1.52968 L^2) $
$ b = (1.7962 - 2.59995 L - 0.27465 L^2) dbh $
$ c = (0.04482 + 0.45997 L - 0.00961 L^2) dbh^2 $
Scribner boardfeet
\( a = (-22.50365 + 17.53508 L - 0.59242 L^2) \)
\( b = (3.02988 - 4.34381 L - 0.02302 L^2) dbh \)
\( c = (-0.01969 + 0.51593 L - 0.02035 L^2) dbh^2 \)
Doyle boardfeet
\( a = (-29.37337 + 41.51275 L + 0.55743 L^2) \)
\( b = (2.78043 - 8.77272 L - 0.04516 L^2) dbhr \)
\( c = (0.04177 + 0.59042 L - 0.01578 L^2) dbh^2 \)
Girard formclass correction
\( cor = (1.0 + ((girard - 78.0) * 0.03)) \)
Tree Volume
\( volume = (a + b + c) * cor \)
Where \( L \) is the merchantable height in 16 foot logs (\( L = mht/16.0 \)), \( dbh \) is the diameter at breast height, and \( girard \) is the Girard form class (default 78)
Example
- Imperial Units
- D = 24 in inches
- L = 2.5 16ft logs (mht 40ft)
- unittype = "Int1/4"
- girard = 78
- Answer = 519.665
- D = 24 in inches
- L = 2.5 16ft logs (mht 40ft)
- unittype = "Int1/4"
- girard = 82
- Answer = 582.025
- D = 24 in inches
- L = 2.5 16ft logs (mht 40ft)
- unittype = "Scribner"
- girard = 78
- Answer = 484.581
- D = 24 in inches
- L = 2.5 16ft logs (mht 40ft)
- unittype = "Scribner"
- girard = 82
- Answer = 542.730
- D = 24 in inches
- L = 2.5 16ft logs (mht 40ft)
- unittype = "Doyle"
- girard = 78
- Answer = 428.942
- D = 24 in inches
- L = 2.5 16ft logs (mht 40ft)
- unittype = "Doyle"
- girard = 82
- Answer = 480.415
Board feet is a imperial units only system.
Code
This code is stored in my Github.com\larsendr site. These are direct links to the raw code.
Excel® Visual Basic Code
R Statistical Package Code
Python Code
Go Code
Javascript for Node Code
C Code
Reference
Mesavage, C., and J. W. Girard. 1946. Tables for estimating board-foot volumei of timber. USDA Forest Servicei, Washington, DC. 94p.
Wiant, Jr. H. V. 1986. Formulas for Mesavage and Girard's volume tables. Northern Journal of Applied Forestry 3(3)124.
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