ASL
Foresters use algorithms to estimate the green (live) weight of trees. The algorithms used in this lesson come from "Tables for Estimating Total Tree and Product Weight and Volume of Major Southern Tree Species and Species Groups" Joseph Saucier and Alexander Clark III , Southwide Energy Committee, American Pulpwood Association Inc., Nov. 1985. These algorithms are good for the South Eastern United States. The principle works for any part of the world but the species and growing conditions vary. If you live in a different part of the US you should contact your county extension agent for trees and algorithms for your area.
ASL
Foresters need to estimate the amount of wood in a forest. For many years foresters carefully measured and weighed trees. They graphed the weight verses the diameter and height for each kind of tree. Next they found formulas that would reproduce the graphs. By using these formulas we can estimate a tree's green weight from its diameter and height.
ASL
First, we need to find your tree's diameter. It is hard to measure through the center of a tree. We can measure the tree's circumference. A tree's circumference becomes smaller the higher up you climb. We need to agree on a place to measure the circumference. Foresters stand next to the tree and measure at chest height.
ASL
Measure your tree's circumference. Use the formula Circumference = 2 * pi * radius to calculate the diameter.
ASL
Estimating the height of a tree.
From Geometry we remember that the ratio of 2 sides of similar triangles are equal. Use this fact to design a procedure to estimate a tree's height.
The algorithms require the two measurements you have made: Diameter at breast height = D (in inches), Height of tree = H (in feet). The lesson's calculators convert the tree's height to inches so the units agree.
For each kind of tree there are two different algorithms. One is for trees with a small diameter and a second for trees with a large diameter.
ASL
|
Tree species |
Size |
Algorithm (calculates weight in pounds) |
|
Southern Pine Coastal plane |
< 5 inches |
0.32214(D2H)0.91330 |
|
|
> 5 inches |
0.19821 (D2)1.06419 (H)0.91330 |
|
Southern Pine |
< 5 inches |
0.28557 (D2H)0.92236 |
|
|
> 5 inches |
0.18703 (D2)1.05385(H)0.92236 |
|
Hard Hardwoods |
< 11 inches |
0.38315 (D2H)0.92045 |
|
|
> 11 inches |
0.11710 (D2)1.16763(H)0.92045 |
|
Soft Hardwoods |
< 11 inches |
0.26153(D2)1.12422(H)0.93871 |
|
|
> 11 inches |
0.10743(D2)1.12422(H)0.93871 |
|
Sweet gum |
< 11 inches |
0.24512(D2H)0.95220 |
|
|
> 11 inches |
0.09605(D2)1.14754(H)0.95220 |
|
Yellow Poplar |
< 11 inches |
0.16258(D2H)0.99008 |
|
|
> 11 inches |
0.12701(D2)1.04157(H)0.99008 |
ASL
Hardwood, or deciduous trees, lose their leaves in the fall. Some hardwood trees actually have soft wood. Red Maple, Paper Birch, Aspen and American Elm are examples of soft hardwood trees. Oak and Hickory are hardwood trees that have hard wood. SEE LIST OF TREES.
ASL
These algorithms give you the green or wet weight of the tree above ground. About 20% of the tree is found in the roots, below ground. Multiplying the green, above ground weight by .2 will give you the weight of the roots. The total green weight of the tree is the sum of the roots and above ground weights.
ASL
Find the green weight of your tree using:
a pocket calculator and the formulas above,
go to the models page and use a computer algorithm.
