Abstract:

Rainfall redistribution of forest canopy is responsible for the transfer of rainfall from a tree canopy to the soil and clearly influences the soil and water conservation in forest ecosystems.Therefore，research on rainfall redistribution is an important consideration from forest ecological and hydrological points of view.The partitioning of gross rainfall into throughfall，stemflow and interception in 〖WTBX〗Cinnamomum camphora〖WTBZ〗 forest were observed at the ecological benefit monitoring station of the Yangtze River protection forest in Cili County，Hunan Province，in order to assess the law of canopy hydrology.Rainfall depth had an impact on rainfall redistribution of 〖WTBX〗C.camphora〖WTBZ〗 forest.Throughfall，interception and stemflow of 〖WTBX〗C.camphora〖WTBZ〗 were positively correlated with rainfall depth (〖WTBX〗P〖WTBZ〗<005).As rainfall increased，throughfall percentage of gross rainfall increased and interception percentage decreased.At higher rainfall depths，throughfall and interception percentage stabilized by degrees.However，stemflow percentage of gross rainfall showed an increasing trend initially and a decreasing trend with the increase of rainfall depth.Rainfall intensity also had an effect on rainfall redistribution.As rainfall intensity increased，throughfall percentage of gross rainfall increased and interception percentage decreased.During the measurement period，throughfall，stemflow and interception of gross rainfall in 〖WTBX〗C.camphora〖WTBZ〗 forest were 68.5%，23% and 292% respectively.Rainfall redistribution of canopy in 〖WTBX〗C.camphora〖WTBZ〗 forest differed significantly among different rainfall depths and rainfall intensity ranges.Furthermore，the components of subcanopy rainfall (the ratio of stemflow and throughfall) were influenced by rainfall depth and rainfall intensity.At the same time，water input beneath the canopy had clearly spatial heterogeneity.Throughfall differed significantly among different sampling sites (〖WTBX〗P〖WTBZ〗<005) and the spatial variation in throughfall (i.e.，coefficient of variation of throughfall percentage) decreased with the increase of rainfall depth and rainfall intensity.

Key words: Cinnamomum camphora, rainfall redistribution, canopy interception, stemflow, hydrological effect, red soil region