vol.fvs.ni.m3: Predicts volume (m^3) from diameter (cm) and height (m) by...

In FAwR: Functions and Datasets for "Forest Analytics with R"

Predicts volume (m^3) from diameter (cm) and height (m) by species, using functions from Wykoff et al. (1982).

Description

This vectorized function uses models and parameter estimates from Wykoff et al. (1982) to predict tree volumes given tree heights (m) and over-bark diameter measurements (cm) taken at 1.37 m (4'6”). The function vol.fvs.ni.bdft performs the computation in imperial units, and vol.fvs.ni.m3 is a wrapper for convenience.

Usage

vol.fvs.ni.m3(spp, dbh.cm, ht.m)
vol.fvs.ni.bdft(spp, dbh.in, ht.ft)

Arguments

spp	Tree species. Must be one of: WP, WL, DF, GF, WH, WC, LP, ES, SF, PP, MH
dbh.cm	Tree diameter, cm, measured at 1.37 m. from the ground.
dbh.in	Tree diameter, in., measured at 1.37 m. from the ground.
ht.m	Tree height, m.
ht.ft	Tree height, ft.

Details

The species are: WP = white pine, WL = western larch, DF = Douglas-fir, GF = grand fir, WH = western hemlock, WC = western red cedar, LP = lodgepole pine, ES = Engelmann spruce, SF = subalpine fir, PP = ponderosa pine, and MH = mountain hemlock.

Value

The function returns a vector of tree volumes, in cubic metres.

Note

The function doesn't perform any input checks. Caveat computator.

Author(s)

Andrew Robinson <[e-mail]>

References

Robinson, A.P., and J.D. Hamann. 2010. Forest Analytics with R: an Introduction. Springer.

Wykoff, W. R., Crookston, N. L., Stage, A. R., 1982. User's Guide to the Stand Prognosis Model. GTR-INT 133, USDA Forest Service, Ogden, UT.

Examples

vol.fvs.ni.m3(c("DF, WH"), c(25, 27), c(15, 20))

FAwR documentation built on June 22, 2025, 5:07 p.m.