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Title: The effect of alder forest cover and alder forest conversion on site fertility and productivity

Conference ·
OSTI ID:6970787

Red alder (Alnus rubra Bong.) is known for its ability to improve the status of soil N through symbiotic N fixation. The objective of this paper is to assess the effect of red alder forests and their removal on soil and solution chemistry and on the growth of trees subsequently established on such sites. This was achieved through a series of paired field comparisons at two locations in Washington, involving similar-aged pure alder and Douglas-fir forests on soils that were essentially the same prior to stand establishment. At Pack Forest alder and Douglas-fir stands on high- and low-productivity sites were subjected to three levels of harvesting: bore only removal, whole tree (aboveground) harvesting, and complete removal of all vegetation and forest floor. The effect of harvesting intensity was examined on nutrient removal with biomass and through leaching, and on subsequent seedling growth. At Thompson Research Center adjacent Douglas-fir and alder forests were harvested, and half of each area was replanted with either Douglas-fir or red alder seedlings, yielding four forest conversion units. Differences in growth patterns, tree nutrient status, and leaching losses between these conversion plots were examined. Compared with adjacent Douglas-fir forests, substantially more N, P, K, and Ca are tied up in aboveground vegetation and on the forest floor of alder forests, and these elements also cycle faster in alder ecosystems primarily due to the deciduous nature of alder.

Research Organization:
Oak Ridge National Lab., TN (USA)
DOE Contract Number:
AC05-84OR21400
OSTI ID:
6970787
Report Number(s):
CONF-8807107-1; ON: DE88016786
Resource Relation:
Conference: 7. North American forest soils conference, Vancouver, Canada, 25 Jul 1988; Other Information: Portions of this document are illegible in microfiche products
Country of Publication:
United States
Language:
English