Comparison of throughfall at Cryptomeria japonica and Fagus crenata stands in FFPRI Tohoku Research Center

Shoji Noguchi, Yasuda Yukio, Murakami Wataru
2007 BulletinofFFPRI)   unpublished
Throughfall is an important element in the hydrologic cycle in forests. The distribution of throughfall at Cryptomeria japonica and Fagus crenata stands in Tohoku, Japan was observed using 50 bucket raingauges over 15 rain storms. The canopy openness above the raingauges was also calculated using hemisphere photographs. The ratio of throughfall to gross rainfall at the Cryptomeria japonica stand ranged from 0.539 to 1.219 (mean: 0.809; SD: 0.139; CV: 17.2%). The ratio depended on the amount of
more » ... d on the amount of rainfall. Dripping points were observed under the canopy edge at the Cryptomeria japonica stand. No linear relationship was found between the ratio of throughfall to gross rainfall and canopy openness at the Cryptomeria japonica stand. The ratio of throughfall to gross rainfall at the Fagus crenata stand ranged from 0.534 to 0.913 (mean: 0.700; SD: 0.096; CV: 13.8%). The ratio didn't depend on amount of rainfall compared to that at the Cryptomeria japonica stand. A weak linear relationship was found between the ratio of throughfall to gross rainfall and canopy openness at the Fagus crenata stand. We could estimate amount of throughfall on large scale (e.g. forest stands scale) using the relationship. These results suggest that the mechanism of throughfall differs between Cryptomeria japonica and Fagus crenata stands. We proposed to examine what influence the shape of the trees, leaf shape, the roughness of the bark, and the tree crown structure, etc. have on throughfall in order to clarify the interception quantitatively.
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