Time Lag Effects and Rainfall Redistribution in Subtropical Evergreen Broad-Leaved Forest in Eastern Coastal China

Abstract

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 inC. fargesiistand andS. Superbastand 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 inC. fargesiistand, which were 30.7%, 7.7%, and 61.6% respectively inS. Superbastand. Rainfall redistribution function ofC. fargesiistand was better than that ofC. fargesiistand. 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 inC. fargesiistand, 6 times shorter than little rainfall event. The lag time of throughfall inS. Superbastand was longer than that in theC. fargesiistand. The time lag shortened gradually as rainfall class increased. Lag time of stemflow was about 2 times than that of throughfall.