水保所知识产出(1956---)知识库

Throughfall in a forest ecosystem has potential hydrological impacts in the semi-arid loess region of China due to
continuous human intervention. However, in black locust forests in this region, throughfall and its spatial het-
erogeneity and controlling factors remain unclear. We examined throughfall, its spatial variability and the effects
of rainfall characteristics and vegetation structure on throughfall in a black locust stand experiment. Of the
489.72 mm cumulative gross rainfall during 20 sampled events, the average of throughfall for all trees, inter-
ception loss (IL) and stemflow (SF) were 380.93 mm (77.71%), 98.48 mm (20.19%) and 10.30 mm (2.10%),
respectively. For a single tree, measured throughfall percentage decreased from upper to bottom in the canopy
vertical layer, and the horizontal distribution increased with distance from the trunk. A correlation analysis
between throughfall and rainfall characteristics, indicated that rainfall amount had a greater effect on
throughfall than rainfall intensity and duration. Throughfall generally occurred following rainfall events of more
than 0.76 mm for black locust. Throughfall percentage initially increased weakly, and then decreased with
increasing rainfall intensity, while it initially increased, and then remained constant with increasing rainfall
duration. Throughfall percentage decreased with increasing leaf area index (LAI) during differently-sized rainfall
events, whereas throughfall variations were different in differently-sized rainfall events. Throughfall is affected
by tree height, diameter at breast height (DBH), canopy width and canopy openness to some degree, while the
effects were higher in larger storms than in smaller storms. Our study highlights the need to consider the effects
of throughfall on hydrological processes, particularly for forest management in semiarid regions.