三峡山地不同林型冠层截留特征及再分配过程研究

森林冠层对降雨的截留和再分配是生态水文学的重要研究内容.截留过程因降雨特征、森林类型及立地环境存在差异.以三峡库区山地的暖性针叶林、落叶阔叶林和针阔叶混交林三种林型为研究对象，对比了2018年植物生长季(4—11月)56场降雨的再分配特征及影响因素.结果表明：1) 降雨在三种林型的再分配特征具有明显差异.暖性针叶林的透流量、树干径流量、林冠截留量分别占同期林外降雨的62.0%、7.2%、30.8%；落叶阔叶林分别占77.9%、3.5%、18.6%；针阔混交林分别占73.3%、2.7%、24%. 2) 再分配参数与降雨量的相关分析显示，三种林型下树干茎流量、透流量均与降雨量呈线性正相关关系，冠层截留量与降雨量呈幂函数关系. 3) 场次降雨特征也会影响再分配，大雨和暴雨时三种林型内降水再分配的动态过程存在明显差异.三种林型的降雨再分配过程因受降雨量、降雨强度等降雨特征和林冠结构的影响而产生差异.针阔叶混交林在强降雨条件下能够更有效地减缓降雨对地表土壤的强烈冲击，减少水土流失.

Canopy interception and redistribution process of different types of forest in the hillslope of the Three Gorges Area

Rainfall interception and redistribution by forest canopy are important research contents of forest hydrology. The interception process varies due to meteorological conditions， forest types and site environment. Three forest types including warm coniferous forest， deciduous broad-leaved forest and coniferous and broad-leaved mixed forest in the Three Gorges Mountain Area were selected as experimental objects to compare the redistribution characteristics and influencing factors of 56 rainfall events in the 2018 plant growing season. The results are shown as follows. 1) The redistribution characteristics of the three forest types were different. The throughfall， stem flow and canopy interception of warm coniferous forest accounted for 62.0%， 7.2% and 30.8% of rainfall outside the canopy， respectively. Deciduous broad-leaved forest accounted for 77.9%， 3.5% and 18.6%， respectively； coniferous and broad-leaved mixed forest accounted for 73.3%， 2.7% and 24%， respectively. 2) The stemflow and throughfall of three forest types were linearly related with rainfall amount， while canopy interception showed a power function relationship with rainfall. 3) The dynamic process of precipitation redistribution in the three forest types was significantly different between heavy rain and heavy rain. The rainfall redistribution process of the three forest types was different due to the influence of rainfall， rainfall intensity and canopy structure. Mixed coniferous broad-leaved forest would alleviate the strong impact of rainfall on surface soil and reduce soil erosion more effectively under heavy rainfall conditions.