Table 3 Volume equations used by FIA-PNW to estimate cubic volume including top and stump (CVTS)

Douglas-fir

WOR & WWA

(Brackett 1977)

\( \mathrm{CVTSL}={\displaystyle \begin{array}{c}-3.21809+0.04948\ \log (H)\ \log (D)-0.15664\ {\left(\log (D)\right)}^2\\ {}+2.02132\ \log (D)+1.63408\ \log (H)-0.1685\ {\left(\log (H)\right)}^2\end{array}} \)

CVTS = 10^CVTSL

EOR & EWA

(Summerfield 1980)

CVTSL =  − 6.110493 + 1.81306  ln(D) + 1.083884  ln(H)

CVTS = exp(CVTSL)

CA^a

(MacLean and Berger 1976)

BA = D² 0.005454154

\( \mathrm{CF}4=-0.248569+0.0253524\ \frac{H}{D}-0.0000560175\ \left(\frac{H^2}{D}\right) \)

If CF4 < 0.3, then CF4 = 0.3; If CF4 > 0.4 then CF4 = 0.4

CV4 = CF4 BA H

\( \mathrm{TERM}=\left(\left(1.033\ \left(1.0+1.382937\ \exp \left(-4.015292\ \left(\frac{\mathrm{DBH}}{10.0}\right)\right)\right)\right)\ \left(\mathrm{BA}+0.087266\right)-0.174533\right) \)

\( \mathrm{CVTS}=\frac{\mathrm{CV}4\ \mathrm{TERM}\ }{\mathrm{BA}-0.087266} \)

Western hemlock

OR, WA, & CA

(Chambers and Foltz 1979)

CVTS = 10^{−2.72170 + 2.00857  log(D) + 1.08620  log(H) − 0.00568 D}