Ck. Muhairwe et al., EFFECTS OF ADDING TREE, STAND, AND SITE VARIABLES TO KOZAKS VARIABLE-EXPONENT TAPER EQUATION, Canadian journal of forest research, 24(2), 1994, pp. 252-259
Crown class, site class, and breast-height age were incorporated into
Kozak's variable-exponent taper equation (A. Kozak. 1988. Can. J. For.
Res. 18: 1363-1368) for three species: Douglas-fir (Pseudotsuga menzi
esii (Mirb.) France), western red cedar (Thuja plicata Donn), and aspe
n (Populus tremuloides Michx.). For lodgepole pine (Pinus contorta Dou
gl.), crown ratio, breast-height age, and quadratic mean diameter were
incorporated into Kozak's taper equation. The effects of adding these
variables to the exponent part of the taper equation on the predictio
n abilities of the taper model were assessed for prediction of diamete
r inside bark along the stem, total tree volume, and tree merchantable
height. It was found that apart from the use of crown ratio for lodge
pole pine, the additional variables resulted in only marginal improvem
ents to the published version of Kozak's taper function. Therefore, th
e cost of measuring these additional variables is not justifiable.