对江苏省 13 个市 70 多条国省干线公路绿化树种的种类、数量和结构进行了调查统计, 结果表明:在树木数
量结构中, 杨树( Populus spp.) 最多, 占总量的 45%, 其他依次为水杉( Metasequoia glyptostroboides Hu et Cheng) 20%、女真( Ligustum lucidum Aifon) 9%、香樟〔Cinnamomum camphora ( L.) Presl〕7%、柳树( Salix spp.) 3 %、银杏( Ginkgo biloba L.) 3%、冬青( Ilex spp.) 2%、松树( Pinus spp .) 2 %和广玉兰( Magnolia grandiflora L.) 2 %, 乔木与灌木的比例为 2∶1。对树种及树种结构因子与环境( 气候) 和经济因素进行了相关分析, 发现除树木种类和密度外, 树种结构因子均与气候或经济因素呈极显著正相关或负相关, 说明这2 个因素对绿化质量影响较大。 采用简单灰色关联法对各市公路绿化系统树种结构综合因子进行了排序和评价, 结果表明:以无锡市的综合性状关联度最高( r =0 .765 1) , 表明该市的绿化结构为最好, 公路绿化发展水平最高, 其次为镇江( r =0.604 2) 和苏州( r =0.592 2) 。
 

The species, quantities and structure of trees in green land system of more than 70 national and provincial roads belong to 13 cities of Jiangsu Province were investigated .In quantity of all tree species, Populus spp .was in the largest numbers ( 45 %) , other principal species Metasequoia glyptostroboides Hu et Cheng ( 20 %) , Ligustum lucidum Aifon ( 9 %) , Cinnamomum camphora ( L.) Presl ( 7 %) , Salix spp .(3 %) , Ginkgo biloba L .( 3 %) , Ilex spp .( 2 %) , Pinus spp .( 2 %) and Magnolia grandiflora L. (2 %) , with a ratio of arbor to bush 2 ∶1 .Relationships among the tree structural indicators and the environmental and economic factors were analyzed .It was found that, except tree species and density, other tree structural indicators exhibited significant positive or negative relationship with climate and economic factors, indicating that greening quality of road was largely effected by this two factors .Besides, Relational analysis of Grey system was used to order and evaluate comprehensive factors of tree structure in city road greening system .The result showed the correlation degree was the highest in Wuxi ( r =0 .765 1) , the next in Zhenjiang ( r =0 .604 2) and Suzhou ( r =0 .592 2) .It was suggested that Wuxi city had more reasonable tree structure and higher level of road greening developing than other cities .