Effects of clear-cutting on nitrogen leaching and fine root dynamics in a cool-temperate forested watershed in northern Japan

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• 作者：Karibu Fukuzawa ; Hideaki Shibata ; Kentaro Takagi ; Mutsumi Nomura ; Noriko Kurima ; Tatsuya Fukazawa ; Fuyuki Satoh and Kaichiro Sasa
• 关键词：Fine root biomass ; Nitrate ; Sasa dwarf bamboo ; Soil solution ; Stream chemistry
• 刊名：Forest Ecology and Management
• 出版年：2006
• 期刊代码：54_03781127
• 类别：abs
• 出版时间：15 April 2006
• 卷：225
• 期：1-3
• 页码：257-261
• 文件大小：257 K

摘要

Stream and soil solution chemistry, fine root biomass and soil nitrogen processing before and after clear-cutting of trees and subsequent strip-cutting of understory vegetation, dwarf bamboo (Sasa senanensis), were investigated to understand the effect of these disturbances on biogeochemical processes on forested watershed in northern Japan. Tree-cutting did not cause a significant increase of nitrate (NO₃⁻) concentration in stream water during the growing season after the cutting. Subsequent Sasa-cutting caused significant increase of stream NO₃⁻ concentration to ca. 15 μmol L⁻¹. There was no significant change of stream pH following both cuttings. NO₃⁻ concentration in soil solution increased after both cutting, but the change of concentration was higher (>100 μmol L⁻¹) after the Sasa-cutting than after the tree-cutting. In a riparian conserved area, on the other hand, NO₃⁻ in soil solution remained low after tree-cutting, suggesting the riparian area acted as a NO₃⁻ sink after the tree-cutting. There was no significant change in total biomass of fine roots after the tree-cutting because of an increase in Sasa root biomass despite a decrease in tree roots. The subsequent Sasa-cutting caused a 50%decrease of fine root biomass compared to that in the un-cut Sasa site. These results suggested that nitrogen uptake by Sasa was very important in preventing nitrogen leaching after tree-cutting, and decline of this nitrogen uptake after Sasa-cutting lead to marked NO₃⁻ leaching to the stream.