Crown Development and Site Estimates in a Douglas-Fir Plantation Spacing Test
Abstract:Relationships among stem and crown dimensions of Douglas-fir were examined 43 years after planting on site IV land at initial spacings of 4 X 4 through 12 X 12 feet. Average dbh, height, and crown dimensions of the largest trees (largest 20 percent or 100 trees per acre by dbh) and of comparable crown classes all increased consistently with increase in initial spacing. Trees of similar dbh or total height were currently quite similar in crown dimensions, although they had arrived at this condition by somewhat different routes. Striking differences among spacings in apparent site indices are attributed mainly to restriction of height growth by competition rather than to real site differences. Average heights of several stand components were compared as bases for site index estimates; heights of a fixed number of the largest diameter trees were most nearly consistent among spacings, although no procedure eliminated spacing effects. Comparisons suggest possible usefulness of live-crown length as one criterion for acceptable site trees in stands of abnormal density. High initial density in low-site stands can lead to serious underestimates of potential productivity. Forest Sci. 16:287-301.
Document Type: Journal Article
Affiliations: Silviculturist, Pacific Northwest Forest and Range Exp. Sta., Forest Service, U. S. Dep. of Agr., Portland, Oreg.
Publication date: September 1, 1970
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- Forest Science is a peer-reviewed journal publishing fundamental and applied research that explores all aspects of natural and social sciences as they apply to the function and management of the forested ecosystems of the world. Topics include silviculture, forest management, biometrics, economics, entomology & pathology, fire & fuels management, forest ecology, genetics & tree improvement, geospatial technologies, harvesting & utilization, landscape ecology, operations research, forest policy, physiology, recreation, social sciences, soils & hydrology, and wildlife management.
Forest Science is published bimonthly in February, April, June, August, October, and December.
2015 Impact Factor: 1.702
Ranking: 16 of 66 in forestry
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