Temporal changes in boreal forest tree canopy cover along a gradient of gamma radiation
作者:
B. D. Amiro,
J. R. Dugle,
期刊:
Canadian Journal of Botany
(NRC Available online 1985)
卷期:
Volume 63,
issue 1
页码: 15-20
ISSN:0008-4026
年代: 1985
DOI:10.1139/b85-003
出版商: NRC Research Press
数据来源: NRC
摘要:
A forest site in southeastern Manitoba has been irradiated by a point source of gamma rays continuously since 1973, and measurements have been made yearly to study the change in boreal forest canopy cover along the radiation gradient. After 10 years of chronic irradiation, a zone of total tree death has resulted from mean dose rates between 25 and 62 mGy h−1. Tree canopy cover was reduced at mean dose rates exceeding ~ 4.5 mGy h−1and the largest reduction occurred in the first 2 years of irradiation. The temporal responses of seven woody species to gamma radiation are presented. Bebb's willow, trembling aspen, speckled alder, and paper birch were less sensitive to radiation than black spruce, balsam fir, and jack pine. The results confirm that gymnosperms are more sensitive to gamma rays than angiosperms.
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