蒙古栎林对大气降雨的再分配规律

Rainfall Redistribution of Mongolian Oak Plantation in Harbin

全面认识和了解森林冠层对降雨的再分配规律,有利于揭示森林生态系统水分循环机制。以哈尔滨市城区蒙古栎人工林为研究对象,通过冠层结构稳定时期的20场降雨数据,分析了蒙古栎林冠层对降雨的截留再分配规律,结果表明:(1)观测期内蒙古栎林的穿透雨量、树干径流量和冠层截留量依次为197.6、62.8、78.8 mm,分别占林外降雨量的58.27%,18.52%,23.24%;(2)根据模型估算,当降雨量超过4.3 mm时蒙古栎林才能够产生树干径流,当降雨量超过6.7 mm开始出现穿透雨;(3)穿透雨、树干径流及林冠截留的绝对量均随降雨量的增大而显著增加,但其占降雨量的比例却表现出不同的变化趋势。(4)穿透雨量的变异系数随降雨量的增大显著减小,二者呈极显著的负相关(p<0.01);(5)蒙古栎生物学特征有利于树干径流的产生,其树干径流量比相同区域内的其他树种高。

Exploring forest canopy redistributing regime of rainfall contributes to reveal water recycle mechanism of forest ecosystem.The Mongolian oak(Quercus mongolica)plantation in Harbin city was selected to study its rainfall redistribution effect and variability via20rainfall events in a growing season.The following results were concluded:1)the throughfall,stemflow and canopy interception in Mongolian oak plantation were respectively197.6,62.8and78.8mm,which accounted for58.27%,18.52%and23.24%of the rainfall in open field;2)throughfall occurred when the outer rainfall exceeded6.7mm and stemflow occurred only if the rainfall exceeded4.3mm according to the model estimates;3)the amount of throughfall,stemflow and interception all increased significantly with increasing rainfall,while their ratios to rainfall showed different trends;4)The coefficients of variability in throughfall decreased significantly with the amount of rainfall increasing,and the two showed a negative correlation(p<0.01);5)the biologic character of Mongolian oak is beneficial to stemflow producing,thus the Mongolian oak produced more stemflow than other species did in common region.