Effect of Dwarf Mistletoe on Bole Taper and Volume in Young Douglas-Fir

Boles of 210 residual understory Douglas-fir trees, ranging from uninfected to heavily infected with Douglas-fir dwarf mistletoe, were measured for cylindrical form factor, Girard form class, height-to-diameter ratio, bole profile, and volume. Height-to-diameter ratio and Girard form class were significantly reduced by dwarf mistletoe across the range of infection classes. However, no effect due to infection by dwarf mistletoe was found on cylindrical form factor, and only a slight difference in bole profile between uninfected and heavily infected trees was found. These results suggest that dwarf mistletoe increases bole taper and affects the volume of younger Douglas-fir by affecting tree diameter and height but not by a substantive change in bole profile. West. J. Appl. For.16(1):5–8.