Green Log and Limb Weight
Green weight and volume of a log or limb from its butt / top diameter, length.
Example
You enter
- Butt (large end) diameter (in) 16
- Top (small end) diameter (in) 16
- Length (ft) 8
- Species (green density) red_oak
You get
- Piece volume 11.17 ft^3
- Green weight (static load) 703.7
Checked against published worked examples from: USDA FPL Technical Note 218 green weights.
Details, formula, and sources
ScopeGreen weight and volume of a log or limb from its butt / top diameter, length, and species green density - the static load every rigging number starts from.
Formula or tablevolume = (pi/3) x length x (r1^2 + r1 r2 + r2^2) with r = dia/24 (frustum; cylinder when butt = top); weight = volume x green density.
Source and editionUSDA Forest Products Laboratory Technical Note 218, Weights of Various Woods Grown in the United States (green column); first-principles frustum volume.
Free accessFPL Technical Note 218 is free at fpl.fs.usda.gov (US government). The frustum volume is public geometry.
What governsEstimate. AHJ and licensed professional govern.
API field namesbutt_dia_in, top_dia_in, length_ft, species, volume_ft3, weight_lb
- Green density TN-218 green weights (red oak 63, coast Douglas-fir 38, slash pine 56, eastern white pine 36, etc., lb/ft^3); generic hardwood 58 and softwood 45 are round figuresUSDA FPL Technical Note 218