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

J.C. Tappeiner, D.W. Huffman, D. Marshall, T.A. Spies, J.D. Bailey
1997 Canadian Journal of Forest Research  
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-gowth stands were significantly greater than those in the young-growth stands. Growth rates in the old stands were comparable with those
more » ... mparable 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.
doi:10.1139/cjfr-27-5-638 fatcat:ftzsuq7qw5cnlfw2mefpmzjzta