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

Abstract

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.