洋浦经济开发区城市森林对降温增湿遮荫的作用

Cooling,Humidifying and Shading Effects of Urban Forests in Yangpu Economic Development Zone

通过实地观测研究洋浦经济开发区城市森林对降温增湿遮荫的作用,以便评价洋浦城市森林的合适程度和树种与结构的适宜性。结果表明,洋浦城市森林具有一定的降温、增湿与遮荫作用,各观测点的平均降温为0.8℃,平均增湿为5%,平均遮荫为94%。但各观测点所代表的树种和结构组成在降温增湿和遮荫方面的效应不一,最热时段的12:00～13:30和13:30～15:00降温最好的是马占相思与椰子混合林;增湿方面最好的是马占相思与椰子混合林、双排椰子林;遮荫最好的是短穗鱼尾葵。洋浦城市森林的降温效果在午间最好,增湿效应则在午前与傍晚最好,遮荫作用在午间最好。相比之下,洋浦城市森林的降温与增湿效应与三亚城市森林的有相当差距,说明洋浦城市森林在面积、行道树林宽度、密度、树种选择与搭配等尚有许多要改善的地方。

On-the-spot measurements were made to determine the cooling,humidifying and shading effects of the urban forests in Yangpu Economic Development Zone with the aim of evaluation of the adequacy of the urban forests in terms of size,layout,tree species and their combination.The results obtained indicated that the urban forests in Yangpu Economic Development Zone did show certain cooling,humidifying and shading effects,0.8 oC decrease in temperature,5% increase in humidity and 94% reduction in solar penetration on average were recorded in the treatments than that in the control.No consistent tendency was observed in the cooling,humidifying and shading effects among the treatment tree species and combinations.During the hottest span of the day at 12：00~13：30 and 13：30~15：00 Acacia mangium Willd.and Cocos nucifera L.combination gave best cooling effects,while Acacia mangium Willd.and Cocos nucifera L.combination as well as two-row Cocos nucifera L.offered best humidifying services,and Carvota mitis Lour.provided best shading results.The best cooling and shading effects of the urban forests in Yangpu were at noon time whilst humidifying effects occurred before noon time and during evening.In comparison with those in Sanya,the urban forests in Yangpu were somewhat inferior in both cooling and humidifying effects.Therefore the urban forests in Yangpu are considered not adequate in size,layout,tree species diversity,tree crown density,tree species combination and roadside tree row width.Recommendations are made to improve the urban forest services by increasing the size,structure and density of the forests,diversifying tree species by introducing some more endemic species,better care and improving the consciousness of the public in urban forest development and maintenances.