城市屋顶绿化资源潜力评估及绿化策略分析——以深圳市福田中心区为例

屋顶绿化是现代城市改善生态环境条件,缓解高密度建成区人为活动负面影响的重要策略选择。以深圳市福田中心区为工作区,利用高精度遥感数据结合设计资料查询和实地调查构建基础数据源;在总结国内外研究成果的基础上,筛选适宜的屋顶绿化约束影响因子,构建资源潜力评估方法;对工作区进行城市屋顶绿化资源潜力评估和绿化策略探讨。结果表明:(1)建筑年代、承重结构、屋顶属性、屋顶小气候是城市屋顶绿化4个方面的主要适建要素,其所涵盖的建筑年代、建筑结构、屋面构造、屋顶功能、屋顶坡度、设备面积、建筑高度和遮荫状况等8个影响因子是决定城市屋顶绿化资源潜力的关键性指标;(2)把城市屋顶绿化纳入城市生态结构和功能建设的整体考虑中,积极开展资源评估、规划研究和配套管理政策建设是推进我国城市屋顶绿化发展重要任务;(3)深圳市中心区现状屋顶绿化率仅9%,剩余构筑物中有51%适合进行全部或部分屋顶绿化覆盖,今后应考虑采取强制、引导和鼓励等不同政策手段,选择适宜的绿化技术方案,对于现有以及正在建设的并且条件适宜的构筑物进行屋顶绿化。

Resource potential assessment of urban roof greening and development strategies: a case study in Futian central district, Shenzhen, China

In recent decades, numerous urban environmental problems have emerged with rapid urbanization in China. Roof greening is an important strategy to improve the ecological environment in modern cities, and to alleviate the negative influence of human activities in high-density, built-up areas. Therefore, such greening has been rapidly developed in many domestic cities. Currently, roof greening in Shenzhen is in the lead position among major cities in China, but remains behind developed cities abroad. As a boom city with a certain international impact, we chose Shenzhen as the study region to do a resource potential assessment of urban roof greening and to explore greening strategies. The aim was to excavate space resources for roof greening, and to formulate greening strategies in accord with the actual state of roof greening development in the city. The study provides necessary theoretical support and a scientific basis for further such development, and has a great reference value to other cities for similar research or practical work. In the present study, we researched the Futian central district of Shenzhen, using as basic data sources remote sensing data, archives of project design, and onsite investigation. Based on a review of relevant research at home and abroad, we selected appropriate impact factors for roof greening, and constructed the method of resource potential assessment. Then, we assessed the resource potential of urban roof greening and explored the greening strategies. Results show that: (1) Construction period, load-bearing structure, roof attribute and roof microclimate are four important factors in urban roof greening. These may be further divided into eight key impact factors for determining the potential of urban roof greening resources. These are construction period, construction structure, roof structure, roof function, pitch, equipment area, building height and shading condition. Roof greening resource potential in urban built-up areas can be effectively assessed using the comprehensive assessment method that is based on the eight indices. (2) The roof greening resources survey showed 201 construction projects in the central district of Shenzhen; 18 of these have implemented roof greening, among which 12 have been only partially greened. The roof greening ratio is only 9%. There are still many roofs in the idle state. Thus, the potential for roof greening is great in the study region, as well as in Shenzhen and other Chinese cities. Among the remaining buildings, 51% are suitable for total or partial greening. The most important limiting factor for roof greening is building height. For policy makers, different approaches should be taken, such as mandatory and inducement measures to afforest existing or under-construction buildings with suitable greening techniques. (3) Roof greening policies and regulations should be improved in China. We should learn from foreign countries with advanced experience, to develop roof greening planning programs and management strategies that address national conditions. Urban roof greening should be included in construction of urban ecological structure and function. Development of resource evaluation, research on planning strategies, strengthening of management and related policy making are primary tasks for developing urban roof greening in our country.