RED ALDER AS A TOOL FOR RESTORING FOREST ECOSYSTEMS IN YOUNG-GROWTH WESTERN HEMLOCK-SITKA SPRUCE STANDS OF SOUTHEAST ALASKA

摘要

Red alder appears to influence the productivity of young-growth conifer forests and to affect the major resources (timber, wildlife, and fisheries) of forested ecosystems in southeast Alaska. Red alder may serve as a useful "tool" for restoring important ecosystem functions in regenerating forests. In this study, overstory stand structure and growth, and understory plant diversity and abundance were assessed in nine 38- to 42-year-old mixed red alder-conifer stands on Prince of Wales Island, Alaska.Tree species composition ranged from 100% conifer to 86% alder as a proportion of stand basal area. Height growth of alder was initially much greater than of conifers, but overstory conifers emerged from alder overstory after 20-30 years and are now 4-9m above the alder canopy. Total understory plant cover and herbaceous cover increased with increasing proportions of red alder. Understory plant communities appeared to be more diverse and abundant in mixed alder-conifer stands than in pure conifer stands. Results suggest that mixed red alder-conifer stands may increase understory plant production and availability for deer forage and improve terrestrial and aquatic habitat for wildlife and aquatic resources.