植物群落特征对夏季公园林荫空间微气候的影响研究

选取福州市西湖公园林荫空间为样地，借助ENVImet软件，引入正交试验设计，探究植物群落特征对夏季林荫空间微气候的影响。结果表明如下几方面。1)树木叶面积指数在所有时段均对林荫空间的降温通风能力起主导作用，降湿效应在早上时段主要受乔灌草比例影响，其余时段主要受树木叶面积指数影响。2)树木叶面积指数、灌木层占比与林荫空间的降温能力呈正相关，与降湿能力呈负相关；乔木植距与冠幅比值略大于1:1时，降温效果最佳；空间的通风效果与树木叶面积指数的关系受树冠高度影响；随着灌木层占比和种植密度的升高，空间风速呈下降趋势。3)降温降湿通风效果最佳的组合方案为：选择叶面积指数高(6.6)的树木，乔灌草比例为3:1:1，种植密度为12m。最后，基于研究结果提出设计策略，为城市公园规划设计提供必要的数据支持和设计依据。

Study on the Influence of Plant Community Characteristics on the Summer Microclimate of the Tree-shaded Space in Parks

This study took the tree-shaded spaces within West Lake Park of Fuzhou as a typical example and used ENVI-met, combined with orthogonal experimental design, to explore the influence of plant community characteristics on micro-climate of the tree-shaded spaces in summer. The results revealed that: 1) Leaf Area Index (LAI) of trees played a leading role in cooling and ventilation capacity of shaded spaces in all periods. The humidity reduction effect was mainly affected by the proportion of trees, shrubs and grasses in the morning, and the leaf area index of trees is mainly affected in the rest of the period. 2) LAI of trees and the proportion of shrubs were positively correlated with the cooling capacity while negatively correlated with the humidity reduction of shade spaces; the cooling effect achieved the best when the ratio of tree planting distance to crown width is slightly over 1:1; and the relationship between ventilation effect and tree LAI was influenced by the height of tree crowns. Besides, with the increasing of shrub layer proportion and planting density, the spatial wind speed presented a downward trend. 3) The best combination plan for cooling, humidity reduction and ventilation was a combination of a high LAI (6.6) of trees, the ratio of arbor, shrub and grass was 3:1:1, and the planting density was 12m. Finally, this study proposed specific design strategies, which offered data basis and design guidance for future urban park planning and design.