Time lag effects and rainfall redistribution in subtropical evergreen broad-leaved forest in eastern coastal China

摘要

In order to reveal the ecological mechanism of rainfall redistribution and lag effects on precipitation of evergreen broad leaved forest in eastern coastal China, 25 m×25 m permanent plot studies were carried in C. fargesii stand and S. Superba stand in Forest Ecosystem Observation and Research station in Tiantong, Zhejiang Province. The results indicated that the total rainfall outside the forest was 5114.0 mm, the average rates of canopy interception, throuhfall, and stemflow were 24.5%, 6.1%, and 69.4% respectively in C. fargesii stand, which were 30.7%, 7.7%, and 61.6% respectively in S. Superba stand. Rainfall redistribution function of C. fargesii stand was better than that of C. fargesii stand. Throughfall and stemflow were increased with rainfall class increasing while canopy interception decreased as rainfall class increasing, especially during typhoon storm period, throughfall was observed after 67.6min when rainfall classes<5 mm happened, while throughfall was observed after 11.8 min when special heavy storm happened in C. fargesii stand, 6 times shorter than little rainfall event. The lag time of throughfall in 5. Superba stand was longer than that in the C. fargesii stand. The time lag shortened gradually as rainfall class increased. Lag time of stemflow was about 2 times than that of throughfall.