Site Index and Height Growth Curves for Douglas-fir in Reference Abstract Cochran, P. H. 1979. Site index and height growth curves for managed, even-aged stands of Douglas-fir east of the Cascades in Oregon and Washington. USDA For. Serv. Res. Pap. PNW-251, 16 p., illus. Pacific Northwest Forest and Range Experiment Station, Portland, Oregon. Height growth and site index curves and equations for managed, even-aged stands of Douglas-fir (Pseudotsuga menziezii (Mirb.) Franco) east of the Cascade Range in Oregon and Washington are presented. Data were collected in stands where height growth apparently has not been suppressed by high density or top damage. KEYWORDS: Increment (height), site index, stem analysis, even-aged stands, Douglas-fir, Pseudotsuga menziesii, Oregon (eastern), Washington (eastern). Introduction Over 9 million of the 20 million acres of commercial forest land in eastern Oregon and eastern Washington is in mixed conifer forests. 2 Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) is a primary component of many of these forests occurring either in pure stands or mixed primarily with white fir (Abies concolor (Gord. & Glend.) Lindl.), grand fir (Abies grandis (Dougl.) Lindl.), western larch (Larix occidentalis Nutt.), or ponderosa pine (Pinus ponderosa Laws.). The site index and height growth curves presented here are for Douglas-fir in pure or mixed, even-aged, managed stands where relatively low density, lack of top damage, and absence of vegetative competition early in the life of the stand permit full height development. A managed stand is being manipulated toward some goal, usually a "target" average diameter and height within a set time frame. To attain these goals, the manager will often use some combination of precommercial and commercial thinnings and perhaps early suppression of competing vegetation. |