The mountain region of Southwest China is not only one of the two key regions that China’s natural forests distributed, but also has lots of degraded natural forests. Its natural forests are essential to keep regional ecosystems safe and biodiversity conservation. The forests geographical zoning plays an important role in regional forests management. Based on plants geographical division and some special topic zonings published, according to zonal climax forest types, land features and drivers of degradation, this paper used the DIVA-GIS and ArcMap, divided the degraded natural forests in mountain areas of Southwest China into five zones, namely tropical rain and monsoon forests of low-mountain in South Yunnan, evergreen broad-leaf and Pinus massoniana forests over limestone in Guizhou-Yunnan, evergreen broad-leaf and Pinus yunnanensis forests of plateau in Central Yunnan, evergreen broad-leaf and Cryptomeria-Metasequoia-Cunninghamia forests of low-mountain around Sichuan Basin, dark coniferous forests over valley and mountains in Sichuan-Yunnan. Introduced the degradation state and main reasons of natural forests of each zone. Zoning of the degraded natural forests at regional level will contribute to the ecological restoration of the degraded natural forests in mountains of Southwest China.

[目的] 基于华北石质山区侧柏人工林2014年（3-10月）降水数据进行量化分析，探究其降水的再分配规律。[方法] 采用野外定位研究方法，对不同结构（郁闭度、枝下高）侧柏人工林林冠层降水再分配特征进行分析。[结果] （1）1/2枝下高0.4、0.6、0.8郁闭度林内穿透雨总量分别为181.1、168.1、147.1 mm，穿透雨率分别为78.8%、73.1%、64.0%；树干径流总量分别为6.0、5.9、3.9 mm；总树干径流率分别为4.2%、2.6%、1.7%；林冠截留总量分别为39.5、56.1、79.1 mm；林冠截留率分别为17.2%、24.4%、34.4%。（2）1/3枝下高0.4、0.6、0.8郁闭度林内穿透雨总量分别为175.6、154.8、136.0 mm，穿透雨率分别为76.4%、67.3%和59.2%，树干径流总量分别为8.3、4.9、3.3 mm，总树干径流率分别为3.6%、2.1%和1.4%，林冠截留总量分别为46.3、70.4、90.7 mm，林冠截留率分别为20.1%、30.6%和39.5%。[结论] （1）侧柏人工林同一枝下高不同郁闭度林分林内穿透雨量差异不显著。2种枝下高郁闭度为0.4和0.8之间的树干径流量均存在显著差异，郁闭度0.4和0.6以及0.6和0.8之间差异不显著。（2）郁闭度为0.4、0.6、0.8时，冠厚占树高2/3（即枝下高为1/3）的林分林冠截留量分别是1/2的1.17、1.25和1.14倍。（3）2种枝下高各自不同郁闭度间林冠截留量均存在显著差异。（4）同等降雨量情况下雨强越大，林冠截留量越小；2次降雨间隔时间越长，林冠层越干燥，林冠截留能力越强；枝下高越低（即冠层厚度越大），林冠截留量越大，且随着郁闭度的增加，林冠截留量逐渐增大。