Canopy interception of sub-alpine dark coniferous communities in western Sichuan, China
川西亚高山不同暗针叶林群落类型的冠层降水截留特征

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%.