北京市常用绿化树种持水能力研究

A study on Water Holding Capacityof Common Greening Tree Species in Beijing

为了评估北京城市绿化主要树种的林冠截留降水能力,采用浸水法测定了14种树种的叶片和枝条的持水量,计算各树种冠层的降水截留能力,并采用聚类分析进行综合评价。结果表明:(1)油松(Pinus tabuliformis)等针叶树种以及金叶榆(Ulmus pumila cv.‘Jinye’)等叶面积指数高的树种的叶片具有较高的持水能力;(2)油松和白蜡(Fraxinus chinensis)等树种的枝条结构粗糙,具有较高的持水能力;(3)枝条在冠层截留中具有重要作用,枝条持水能力占冠层总持水能力的9.73%~62.03%,平均达到35.76%;(4)综合叶片、枝条和冠层持水能力,油松、刺槐(Robinia pseudoacacia)、白蜡、旱柳(Salix matsudana)持水能力较强,可用于建设更高效截留能力的城市绿地。

The water holding capacity of the leaves and branches of 14 tree species is measured by the water immersion method and the rainfall interception capacity of the canopy of each tree species is calculated in order to evaluate the rainfall interception capacity of the main tree species for urban greening in Beijing.In addition,cluster analysis is employed to comprehensively evaluate the water holding capacity of the tree species.The results are as follows:(1)The leaves of coniferous species such as Pinus tabulaeformis and species with high leaf area index such as Ulmus pumila have higher water-holding capacity;(2)P.tabulaeformis and Fraxinus chinensis have rough branch structure and higher water-holding capacity;(3)Branches have played an important role in canopy water interception,and the water-holding capacity of branches has accounted for 9.73%~62.03% of the total water-holding capacity of tree canopy(35.76% on average);(4)In terms of the water holding capacity of leaves,branches,and canopies,Pinus tabulaeformis,Robinia pseudoacacia,Fraxinus chinensis,Salix matsudana have strong water holding capacity,which can be used to build urban green spaces with more efficient interception capacity.