亚高山林区河岸带康定柳木质残体持水能力随径级的变化特征

Changes in water holding capacity of Salix paraplesia woody debris with diameter classes in riparian zone of subalpine forest

为了解亚高山林区河岸带木质残体的持水能力,以王朗国家级自然保护区亚高山林区河岸带康定柳(Salix paraplesia)直径>30、30~20、20~10、10~5、5~2和2~1 cm六个径级的木质残体为研究对象,运用浸泡模拟法研究了其吸水过程和持水能力随径级的变化特征。结果表明:不同径级木质残体的最大持水量为1024.78~2674.67 g·kg-1,不同径级木质残体的持水量大小顺序为10~5、20~10、30~20、>30、2~1、5~2 cm;不同径级的木质残体在吸水过程中随着浸泡时间的增加,其饱和含水量不断升高,吸水速率不断降低。同时,30~5 cm径级的木质残体具有良好的持水能力与吸水能力。川西亚高山林区不同径级的康定柳木质残体持水能力差异明显,建议在河岸带保留较大径级的木质残体,有利于提高河岸带水源涵养功能。

To understand the water holding capacity of woody debris in the riparian zone of subalpine forest,water absorption process and water holding capacity of Salix paraplesia woody debris with six different diameter classes(>30,30-20,20-10,10-5,5-2 and 2-1 cm)were measured in the subalpine riparian zone of Wanglang National Nature Reserve by water immersion method.The results showed that the maximum water holding capacity across all diameter classes varied from 1024.78 to 2674.67 g·kg-1.Water holding capacity from high to low was in order of10-5,20-10,30-20,>30,2-1,and 5-2 cm.The saturated water content increased over time during the process of water absorption,and the water absorption rate decreased.Woody debris with 30-5 cm diameter classes had good water holding capacity and water absorption capacity.In conclusion,retention of woody debris with larger diameter in the riparian zone is beneficial to improving the function of water conservation.