北京九龙山不同结构侧柏人工纯林降水的再分配

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。

Effects of Different Structure of Platycladusorientalis Plantation in Beijing Jiulongshan on Redistribution of Precipitation

Objective] Based on the precipitation data of 2014 toanalyze quantitatively the law of redistribution of precipitationin mountainous area of North China. Method] The method of field positioning was used to analyze the rainfall redistribution of Platycladusorientalis plantation with different structure (canopy, under branch height)characteristics. Result] (1)At the height of 1/2 under branch height, the through rainfalls of stands with canopy density of 0.4, 0.6, 0.8 respectively were 181.1, 168.1, and 147.1 mm, the rates of through rainfall were 78.8%, 73.1%, and 64.0%; The total stemflowswere 6.0, 5.9 and 3.9 mm respectively, the rates of stemflowwere 4.2%, 2.6% and 1.7%. The total canopy interceptionswere respectively 39.5, 56.1 and 79.1 mm. The rates of canopy interception were 17.1%, 24.4% and 34.4%. (2) At the height of 1/3 under branch height, the through rainfall of stands with canopy density of 0.4, 0.6, 0.8 canopy were 175.6 mm, 154.8 mm, and 136.0 mm, the rates of through rainfall were 76.4%, 67.3%, and 59.2%. The total stemflowswere respectively 8.3, 4.9 and 3.3 mm, the rates of stemflowwere 3.6%, 2.1% and 1.4%. The total canopy interceptionswere respectively 46.2, 70.4 and 90.6 mm. The rates of canopy interception were 20.1%, 30.6% and 39.4%. Conclusion] (1) At the same under branch height, the difference in through rainfall of P. orientalisplantation with different canopy coverage was not significant. The stemflow between the stands with canopy density of 0.4 and 0.8 showed significant difference, while the difference between the canopy density of 0.4 and 0.6 and between the canopy density of 0.6 and 0.8 were not significant.(2) At the stand with the density of 0.4, 0.6, and 0.8, the canopy interception of the stand with crown thickness accounts for 2/3 the tree height were 1.17, 1.25 and 1.14 times that of the stand with crown thickness accounts for 1/2 the tree height. (3) Significant differences in crown interception were found among different canopy density. (4) At the same rainfall intensity, the more the rainfall, the smaller the canopy interception; the longer the interval of rainfall time, the drier the canopy drier and the stronger the interception ability; The lower the branch height, the larger the canopy interception amount and with the increase of the canopy density, the canopy interception increased.