校园内不同树种行道树及不同类型绿地遮光效应的比较

本文以内蒙古农业大学东校区的水泥路面作为对照,利用照度计原位观测了校园内3种主要行道树,即垂柳、新疆杨、油松和3种类型绿地即乔+灌+草、乔+草、草坪的光照度,比较了不同树种行道树及不同类型绿地的遮光效应.研究结果表明:对照点和3种行道树光照度的日变化趋势均呈倒“U”字型,除了乔+草绿地类型外,其它绿地光照度的日变化趋势呈倒“V”字型.与对照相比,垂柳、新疆杨、油松林3种主要行道树都具有明显的遮光效应,其遮光效应分别为30.5％、20.4％、35.9％,大小表现为油松林＞垂柳＞新疆杨,这种效应的出现可能与不同树种树冠的几何形状、叶面积指数以及树木长势及枝下高等的有关.就不同类型绿地的遮光效应而言,乔+灌+草和乔+草两种绿地类型的遮光效应分别为43.5％和43.9％,均显著大于草坪和水泥路面,而草坪与对照水泥路面之间的遮光效应没有显著性差异.要提高绿地的遮光效应,应选用树冠较大及枝叶浓密的乔木树种,并应在空间上合理配置.

RESEARCH ON THE SHADING EFFECT OF DIFFERENT STREET TREES AND GREEN LANDS IN INNER MONGOLIA AGRICULTURAL UNIVERSITY

We selected three street trees named Salix babylonica Linn.,Populu sbolleana Lauche.And Pinus tabulaeformis Carr.and three green lands named tree + shrub + herb,tree + herb and lawn in the eastern campus of Inner Mongolia agricultural University,the shading effects of different greenery trees and the street trees was analyzed.The results shows that: The diurnal variation trend of three street trees together with the nearing naked and cement land(CK) was inverted U curve coincidently,while the green lands ’s diurnal variation shows inverted V curve except of tree + herb.Compared with the cement land,three street trees all has obvious shading effect,the order is Pinus tabulaeformis﹥Populu sbolleana Lauche.﹥Carr.Salix babylonica Linn.,the shading effect is 30.5%、20.4%、35.9% respectively.This phenomena may be related with the geometrical shape of tree crown,index of leaf area and the growth state and the branch height.The shading effect of tree+ shrub+ herb and tree+herb are significantly higher than the lawn and the cement land,the shading effect for the lawn and the cement land is 43.5% and 43.9% respectively,while the shading effect between the lawn and the cement land has no difference.