Comparison and Development of Height Growth and Site Index Curves for Douglas-Fir in the Inland Northwest

Stem analysis data from Douglas-fir (Pseudotsugam enziesii) collectetd throughout the inland Northwest were used for testing height growth and site index equations. The equations performed well in northern and centraI ldaho, northeast Oregon, and northeast Washington on vegetative types similar to those sampled in model development. However, if the equations were applied on drier sites outside the original geographic study area, overestimates of height growth and underestimates of site index could result. Therefore, revised height growth and site index equations are presented for western Montana and central Washington