北京建成区道路绿化空间结构和行道树健康状况

采用实地普查测量方法，定量研究了北京建成区188条道路行道树的树种结构、径级分布、立木层次和健康状况。结果表明，国槐（Sophora japonica）、毛白杨（Populus alba）、银杏（Ginkgo biloba）是建成区主要行道树种，使用量分别占研究区树木总株数的54．7％、13．7％和7．4％。建成区树木...

Spatial Structure and Health Condition of Street Trees in Beijing Built-up Areas

The structure and health condition of street trees were investigated by using aerial photograph method in Beijing built-up areas. The species composition, tree DBH （diameter at breast height） , tree stratum and health condi- tion were analyzed. The results showed that Sophora japonica （54.7%） , Populus alba （ 13.7% ） and Ginkgo biloba （7.4%）were the dominant species according to their individual percent of contribution. The average density was 201 tree/hm2 and the average DBH was 18.5 cm in the study area. Nearly 12 percent of trees were classified as big tree （DBH≥50 cm）, and the small trees mainly occupied the range of 10 cm≤DBH 〈 20 cm. In addition, the average height of trees was 8.9 m. Only 6 percent arbors were higher than 15 m, and the pruned trees had a large percent as high as 86.7%. Most of the other arbors were small which mainly accounted for the stratum of 5 m≤H 〈 10 m. Nearly 74 percent trees had good or medium health level, but there were more than 26 percent trees in poor health condition which was influenced by pruning and ground cover greatly.