几种行道树对惠州市城市道路微气候的影响

Effect of several kind street trees on microclimate over avenue in Huizhou city

行道树是城市道路绿化的骨干树种,对道路景观有着统领的作用,对改善环境生态有积极作用。为了弄清岭南城市主要行道树对城市道路的微气候影响,以惠州市为例,对惠州主要道路的9个常见行道树种进行了遮荫效果调查。结果表明:所有行道树都具有一定的遮光率和降温率,遮光效果较好的树种是白兰,其遮光率达95.81%,较差的是王棕和长芒杜英,遮光率为61%~63%,其它树种介于两者之间。降温率最高的树种是榕树,其降温率达9.83%,温度可下降3.5℃,降温较差的是长芒杜英,其降温率为1.5%,温度仅下降0.5℃。综合荫质与遮荫效果,遮荫效果较好的树种是榕树,较差的是王棕与长芒杜英,而白兰、海南红豆、非洲楝、高山榕、黄葛树亦具有较好的遮荫效果。今后选择岭南城市的行道树在注重遮荫功能时可优先选择榕树、白兰、海南红豆、非洲楝、高山榕、黄葛树,注重景观特色而对遮荫要求不高时可选王棕与长芒杜英。

The street trees is main tree species on city’s road greening.It has very important function on street road landscape and positive roles on environment and ecology.In order to figure out the shading effect of street trees in southern city, Huizhou city has been took as an example by author. The nine common street trees which grow in Huizhou city avenue had been investigated. The results showed that all street trees have a certain shading rate and cooling rate. The Michelia alba tree has the better shading effect. It’s shading rate was 95.81 percent, The poorer is 61 percent for Roystonea regia and 63 percent for Elaeocarpus apiculatus, and other species are somewhere in between of Michelia alba and Roystonea regia with Elaeocarpus apiculatus. The Ficus microcarpa tree has more higher temperature drop rate, it’s cooling rate was 9.83 percent, and it’s temperature drop 3.5 ℃. The Elaeocarpus apiculatus has more poorer cooling rate, it’s cooling rate only was 1.5 percent, the temperature drop only 0.5 ℃. Combining with the quality of shade and shading effect, the better tree species of shading is the Ficus microcarpa, the poor one is Roystonea regia and Elaeocarpus apiculatus, while the Ormosia pinnata, Khaya senegalensis, Ficus altissima, and Ficus altissima also has good shading effect. In the future, this trees as Ficus microcarpa, Michelia alba, Ormosia pinnata, Khaya senegalensis, Ficus altissima, and Ficus lacor, it will be chosen preferentially as an street trees when it be paid attention to its shade function in the Lingnan city, when the landscape characteristics can be paid attention to, the trees as Roystonea regia and Elaeocarpus apiculatus can be chosen.