川西亚高山不同暗针叶林群落类型的冠层降水截留特征

在林分和小流域尺度上,应用模型研究了四川卧龙亚高山暗针叶林冠层的降水截留特征.结果表明:生长季节(5—10月),箭竹-岷江冷杉原始林冠层截留系数在33%～72%之间,平均48%;冠层截留量与降水量之间呈显著的线性关系,截留系数与降水量之间呈负指数函数关系;试验小流域内,植被冠层最大截留量的平均值为1.74mm,不同林分间的差异显著,其顺序为藓类-箭竹-岷江冷杉林>草类-箭竹-岷江冷杉林>藓类-杜鹃-岷江冷杉林>草类-杜鹃-岷江冷杉林>杜鹃灌丛;冠层最大截留量与叶面积指数(LAI)之间呈极显著的线性关系;冠层截留量、冠层最大截留量、附加截留量分别占同期降水量的39%、25%和14%.所选模型对整个生长季平均截留量的模拟效果较好,相对误差为9%～14%.

Canopy interception of sub-alpine dark coniferous communities in western Sichuan, China

Based on field measurements of throughfall and stemflow in combination with climatic data collected from the meteorological station adjacent to the studied sub-alpine dark coniferous forest in Wolong,Sichuan Province,canopy interception of sub-alpine dark coniferous forests was analyzed and modeled at both stand scale and catchment scale.The results showed that monthly interception rate of Fargesia nitida,Bashania fangiana-Abies faxoniana old-growth ranged from 33% to 72%,with the average of 48%.In growing season,there was a linear or powerful or exponential relationship between rainfall and interception and a negative exponential relationship between rainfall and interception rate.The mean maximum canopy interception by the vegetation in the catchment of 1.44 km2 was 1.74 mm and the significant differences among the five communities occurred in the following sequence:Moss-Fargesia nitida,Bashania fangiana-A.faxoniana stand>Grass-F.nitida,B.fangiana-A.faxoniana stand>Moss-Rhododendron spp.-A.faxoniana stand>Grass-Rh.spp.-A.faxoniana stand > Rh.spp.shrub.In addition,a close linear relationship existed between leaf area index(LAI)and maximum canopy interception.The simulated value of canopy interception rate,maximum canopy interception rate and addition interception rate of the vegetation in the catchment were 39%,25% and 14%,respectively.Simulation of the canopy interception model was better at the overall growing season scale,that the mean relative error was 9%-14%.