Effects Of Summer Landscape Plant Communities On Microenvironment And Climate In Guangzhou Residential Areas

With the development of economy and people's pursuit of quality of life,the quality of residential environment has been paid more and more attention.Building a comfortable residential environment is also an important issue in the current ecological construction environment.In this paper,the characteristics of 25 plant communities in five residential areas of Guangzhou are analyzed,and the objective meteorological factors are measured.Through the analysis of the data,the changes of temperature and humidity in the microclimate environment of different communities are compared,and the factors affecting the comfort degree of microclimate environment are found out,and the relevant suggestions for the design and maintenance of plant communities in residential areas are put forward.The results show that:(1)Landscape plant communities have significant cooling and humidifying effects on microclimatic environment.The temperature and humidity of the community were significantly different from those of the control group(P < 0.05).The community could decrease the temperature by 1.04-2.68 C and increase the humidity by 1.44%-15.55%.(2)Different underlying surfaces have different cooling and humidifying rates.The lowest temperature and humidity increase rate was found in the plant communities covered by the ground.The order of cooling rate is: ground cover(6.24%)> permeable pavement(5.41%)> wood pavement(4.86%)> cement hard pavement(4.31%).The order of humidification rate is: ground cover(17.83%)> wood trestle(9.83%)> permeable pavement(9.66%)> cement hard pavement(8.07%).The cooling rate of ground cover was1.42% and 8.81% lower than that of cement hard pavement(p > 0.05);the cooling and humidifying rates of plant communities with different planting structures were different,arbor-shrub-grass(5.61%)> arbor-shrub-grass(4.97%)> arbor(4.42%).Tree-shrub communities have the highest cooling rate because of the more comfortable plant space.In terms of humidification rate,arbor shrub grass(10.92%)> arbor shrub(8.93%)> arbor shrub(8.25%).Because of the richer plants in arbor,shrub and grass communities,the transpiration of plants is stronger and the humidification rate is the highest.There was no significant difference in the cooling and humidifying rates among the three planting structures(p < 0.05);the leaf area index in plant communities was positively correlated with the cooling and humidifying rates of the communities.The formula of fitting curve is as follows:Cooling rate:y = 0.0044 x + 0.0374,R2 = 0.1777(a < 0.05)Humidification rate: y = 0.0083 x + 0.0813,R2 = 0.0463(a < 0.05)(3)Landscape plant communities can improve microclimate comfort.The degree of comfort improvement was between 3.32% and 10.39%.The comfort degree of 25 communities was divided into uncomfortable and uncomfortable,14 communities were evaluated as uncomfortable,11 roads were evaluated as uncomfortable,and the comfort degree of control points was evaluated as uncomfortable and uncomfortable.The degree of improvement of community comfort of different underlying surfaces in residential areas is different.The performance from high to low is ground cover(7.07%)> permeable pavement(6.00%)> wooden pavement(5.33%)> cement hard pavement(4.67%)and the other three types are significantly different(p < 0.05),but the other three types are not significantly different(p > 0.05).The improvement degree of comfort degree of different planting structures was different,the order was arbor,shrub and grass(5.91%)> arbor and shrub(5.50%)> arbor(4.60%).The comfort degree of arbor-shrub-grass structure was significantly different from that of Arbor-shrub structure(p < 0.05),but the difference between Arbor-shrub structure and Arbor-shrub structure was not significant(p >0.05).(4)Solar radiation,building height,wind speed,water body and community location are also factors affecting community comfort.Solar radiation directly affects the light intensity of the community,and brings radiation heat,which makes the community warm and humid.The high buildings in the residential areas are between 11 and 31 stories,and the high buildings are between 31 and 93 meters,which shield part of the sunshine.Under the combined action of plants and buildings,the illumination intensity in the community changes irregularly.Communities with better comfort are generally located at the entrance ventilation of residential areas,with water body,rich vegetation and large shade area of leisure areas.In summer,8:00-20:00,8:00-9:00 is the most comfortable time of the day,which is suitable for residents to go out or do morning exercises.From 25 plant communities,10 plant communities with a comfort improvement of more than 6% were selected,and their characteristics were analyzed.Suggestions on the design and maintenance of residential garden plant communities were given from the factors affecting the comfort.In order to improve the comfort of community,we should start with increasing water body,greening and shading design,underlying surface design,reasonable shrub and grass collocation,and ventilation-oriented design.At the same time,attention should also be paid to the management and maintenance of daily plant communities,planting a number of plants adapted to the local climate and environment.The community comfort was maintained by pruning plants and supplying vacant plants.This study provides more scientific data basis and guidance for the design and maintenance of plant communities in residential areas based on micro-climate comfort,lays a foundation for building a good human settlements environment,and contributes a little to the construction of ecological civilization.