Ecosystem Effects of Sitka Alder in a Douglas-fir Plantation
Ecosystem Effects of Sitka Alder in a Douglas-fir Plantation
复制标题
花旗松人工林中西特卡桤木的生态系统效应
DOI:
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发表时间:
1984
期刊:
影响因子:
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通讯作者:
K. Cromack
中科院分区:
文献类型:
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作者:
D. Binkley;J. Lousier;K. Cromack
The natural seeding of Sitka alder (Alnus sinuata (Regel) Rydb.) into a portion of a Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) plantation afforded an opportunity to assess the effects of shrubby Sitka alder on Douglas-fir growth and nutrient content, on ecosystem biomass, aboveground net primary production, and litterfall, and on soils. Estimated accretion ofnitrogefi (N) was 30 kg ha - yr - for 23 years in the Sitka alder/Douglas-fir ecosystem. Though Douglas-fir stocking and basal area were not significantly affected by Sitka alder, current average dbh was 13 percent greater, 5-year average basal area growth 33 percent greater, and stem biomass increment 40 percent greater on the Sitka alder site. Nitrogen concentrations in Douglas-fir foliage increased significantly with Sitka alder present, but concentrations of phosphorus and sulfur were markedly reduced. Nutrient content of litterfall was 3 to 7 times greater on the Sitka alder site, and the soil-N availability index was 3-fold greater. Moderate N-fixation rates and shrubby growth form of Sitka alder combine to make it an attractive species for mixture with conifers on N-deficient sites. FOREST SCI. 30:26-35.