by David R. Larsen
The School of Natural Resources
University of Missouri

The purpose of the website is to provide a range of computer functions that are of use to foresters. Initially, the functions will be provided in as Excel® VBS functions, as R Statisticial package functions, as Python functions and as Go Language functions. I provide my explaination of each function, references to the source to the equations, and source code with test data.

Key: Topics

Summary Statistics (Stand)

Quadratic Mean Diameter (Stand)
A quadratic mean of the diameter values. A quadtratic mean is the diameter of the tree of average basal area.
Basal Area Per unit area (Stand)
Calculate the total basal area per acre or hectare. Basal area is the cross-sectional area of the stems on an acre or hectare.
Site Index (Stand)
A measure of site productivity based on age and tree height

Stocking Statistics (Stand)

Stand Density Index (Stocking)
A measure of relative stand stocking tranlated into 10" or 25.4cm trees.
Percent Stocking (Stocking)
A Gingrich percent stocking calulation for a specific tree per acre and basal area.
Gingrich Stocking Diagram (Stocking)
A Gingrich Stocking Diagram

Volume Equations (Log)

Cubic (Log Volume)
Cubic volume (feet or meters) is calculated as the frustum of a geometric shape.
Doyle (Log Volume)
Doyle log volume.
Scribner (Log Volume)
Scribner log volume.
International (Log Volume)
Board foot log equations are an estimate of the board foot products that people will make from a log of specified dimensions.

Volume Equations (Tree)

Beer's Tree Volume (Volume)
Tree volume equations estimate the cubic or board foot volume is a tree given diameter at breast height and the merchantable height.
Mesavage and Girard's Tree Volume (Volume)
The board foot tree volume equations produce the number in Mesavage and Girard. 1946. Tree volume tables.
Wood Density (Volume)
Determine the weight of a cubic unit of wood given specific gravity & moisture content.

Acorns (Tree)

Average Acorn Weight (Volume)
Average acorn weight in pounds as predicted from Diameter at breast height (DBH) and species of oak. a Table from Down, 1944 was fit with polynomial equations to allow a formula represntation of the tabular data.



Avery, T. E., H. E. Burkhart. 2002. Forest Measurments 5th Edition. McGraw-Hill. ISBN 0-70-366176-7. 456 pp.
Husch, B., T. W. Beers, J. A. Kershaw, Jr.. 2003. Forest Mensuration 4th Edition. John Wiley & Sons. ISBN 0-471-01850-3. 443 pp.
Johnson, P. S., S. R. Shifley, and R. Rogers. 2002. The Ecology and Silviculture of Oaks. CABI Publishing. ISBN 85199-570-5. 356 pp.
Shivers, B. D., B. E. Borders. 1996. Sampling Techniques for Forest Resource Inventory Mensuration. John Wiley & Sons. ISBN 0-471-10940-1. 365 pp.


Beers, T. W.. 1964. Composite Hardwood Volume Tables.. Purdue University, Agricultural Experiment Station, Lafayette, IN. Research Bulletin. (787):12 p.
Gingrich, S. F.. 1967. Measuring and evaluating stocking and stand density in Upland Hardwood forests in the Central States.. Forest Science. 13():38-53.
Kershaw, Jr, J. A. and B. C. Fischer. 1991. Maximum size-density relationships for sawtimber-sized mixed upland central hardwoods.. In: "The 8th Annual Central Hardwoods Conference", L. H. McCormick and K. W. Gottschalk eds. USDA, Forest Service, Northeastern Forest Experiment Station, General Technical Report. (NE-148):414-428.
Krajicek, J. E. and K. A. Brinkman and S. F. Gingrich. 1961. Crown competition-a measure of density. Forest Science. 7():35-42.
Larsen, D. R. Dan C. Dey and T Faust. 2010. A Stocking Diagram for Midwestern Eastern Cottonwood-Silver Maple-American Sycamore Bottomland Forests. Northern Journal Of Applied Forestry. 27(4):132-139.
McGill, D. W. and R. Rogers, A. J. Martin, and J. S. Johnson. 1999. Measuring Stocking in Northern Red Oak Stands in Wisconsin. Northern Journal Of Applied Forestry. 16(3):144-150.
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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Natural Resources Biometrics by David R. Larsen is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

Author: Dr. David R. Larsen
Created: June 21, 2015
Last Updated: June 21, 2015