Density, ages, and growth rates in old-growth and young-growth forests in coastal Oregon

J. C. Tappeiner; D. Huffman; T. Spies; John D. Bailey

doi:10.1139/x97-015

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Density, ages, and growth rates in old-growth and young-growth forests in coastal Oregon

J. C. Tappeiner·D. Huffman·T. Spies·John D. Bailey

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Abstract

We studied the ages and diameter growth rates of trees in former Douglas-fir (Pseudotsuga menziesii (Mirb.)Franco) old-growth stands on 10 sites and compared them with young-growth stands (50-70 years old, regenerated after timber harvest) in the Coast Range of western Oregon. The diameters and diameter growth rates for the first 100 years of trees in the old-growth stands were significantly greater than those in the young-growth stands. Growth rates in the old stands were comparable with those from long-term studies of young stands in which density is about 100-120 trees/ha; often young-growth stand density is well over 500 trees/ha. Ages of large trees in the old stands ranged from 100 to 420 years; ages in young stands varied by only about 5 to 10 years. Apparently, regeneration of old-growth stands on these sites occurred over a prolonged period, and trees grew at low density with little self-thinning; in contrast, after timber harvest, young stands may develop with high density of trees with similar ages and considerable self-thinning. The results suggest that thinning may be needed in dense young stands where the management objective is to speed development of old-growth characteristics.

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J. C. Tappeiner, D. Huffman, T. Spies, John D. Bailey. 1997. Density, ages, and growth rates in old-growth and young-growth forests in coastal Oregon. https://doi.org/10.1139/x97-015

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