基于i-Tree模型的湛江市行道树冠层截留雨水效益分析

行道树是城市森林的重要组成部分，在冠层截留降雨方面起着十分重要的作用，研究城市行道树冠层截留雨水的能力和价值有利于对其进行筛选。通过i-Tree tools对湛江霞山区、开发区、赤坎区3个中心主城区的行道树抽样调查，进行定量的冠层截留雨水生态效益分析评估。湛江市区种植有行道树种67种，分别隶属于52个属，其中细叶榕、小叶榄仁、大王椰子、非洲楝、椰子数量最多，除细叶榕之外，其他树种的比例均<10%；行道树胸径范围以7.6~15.2、15.2~30.5、30.5~45.7 cm这3个径级为主，其中胸径15.2~30.5 cm的占42.7%；湛江市行道树叶面积总计8 600 854 m²，树冠覆盖面积达2 905 896 m²；单株叶面积最大的为黄葛树，其次为非洲楝；湛江市行道树年冠层截留量达689 041.96 m²，获得的经济效益为350.2万元，平均单株年冠层截留降雨量获得的效益为43.4元，其中单株效益最高的是黄葛树，其次是非洲楝，再是细叶榕。较大的叶面积及冠幅对于增强冠层截留雨水能力起到很大作用，在暴雨成灾的南方，可以选择黄葛树、非洲楝和细叶榕这些冠层截留率大的行道树。

Beneficial Analysis of Rainwater Interception by Street Trees in Zhanjiang City Based on i-Tree Model

Roadside trees are an important part of the urban forest and play a very important role in terms of trapping rainwater.The study of the ability and the value of urban roadside trees to intercept rainwater is beneficial to the selection of roadside trees.Through i-Tree tools,this paper conducted a quantitative analysis and evaluation on ecological benefits of rainwater interception through the sampling survey of roadside trees in the main urban areas of the three central districts(Xiashan,Development,and Chikan)in Zhanjiang.It was found that in the urban area of Zhanjiang,67 species of tree were planted,belonging to 52 genera.Among them,Ficus microcarpa,Terminalia neotaliala,Roystonea regia,Khaya senegalensis and Cocos nucifera were the most plentiful.The proportion of other tree species was less than 10%,except for F.microcarpa.The diameters of roadside trees were dominated by three ranges:7.6 to 15.2,15.2 to 30.5,and 30.5 to 45.7 cm.In Zhanjiang City,the total area of roadside trees was 8600854 m 2,and the area of canopy cover was 2905896 m 2.The largest leaf area per individual tree was F.virens,followed by K.senegalensis.According to the software analysis,the annual intercept rainfall of roadside trees in Zhanjiang city reached 689041.96 m 3,from which the economic benefit was 3502000 yuan RMB,and the average annual intercept rainfall of a single plant was 43.4 yuan.Among them,the highest benefit per plant was F.virens,followed by K.senegalensis,and F.microcarpa.Roadside trees play a significant role in intercepting rainwater in urban forests.Large leaf area and canopy breadth play a significant role in enhancing the ability of the canopy to intercept rainwater.According to the needs of interception amount,fast-growing tree species with large interception rate can be selected for cultivation in flash-flooding south.