Temperature And Humidify Effect And Psycho-physiological Influence Of Plant Communities In Shenzhen Urban Green Areas

Green plant is an indispensable and important infrastructure of urban ecology, which not only can improve urban environment and enhance green coverage ratio, but also can bring us physical and mental pleasure and beautiful enjoyment. Landscape plant community is the elementary unit of urban landscape and the ecological basis of urban green space system. Scientificity and rationality of plant community design has a profound and far reaching significance and long term influence on elevating the level of urban greening, ameliorating the urban microenvironment, creating better living environment and playing the important role of plants.500～600m2plant community is widely used and plays an important role in urban planning. Large-scale landscapes, such as urban green space and the whole park were chosen as research object in previous researches, however, little work has been done on the ecological benefit of small-scale plant communities, and there is no quantitative analysis of the psycho-physiological influence of plantscapes on human. In order to design scientifical plantscapes, help small-scale plant communities work better, and realize the maximization of ecological benefits and health function of plant communities to provide guidelines for livable environment, a survey on the landscape plant arrangement in park green space of Shenzhen City was carried out with the method of stratified sample combined with random sample. Based on the results, this paper utilized interdisciplinary knowledge (including Ecology, Landscape Aesthetics, Rehabilitation Medicine and Psychology) and some methods (including fixed point observation and psychological questionnaire), and analysed the temperature and humidify effect of fifteen small-scale plant communities and psycho-physiological influence of plantscapes on human. Moreover, in order to explore sound effect on human in plantscapes, we analysed psycho-physiological influence of planrscapes and sounds on human.The main research results were as follows:1. There were595species of plants in urban parks in subtropical Shenzhen City. It indicated that the application frequencies of plants were mainly concentrated in f≤20%. In comparison with specie richness index, diversity index (Simpson and Shannon-Wiener) and evenness index, species diversity of various plant communities was different. These findings, including analysis of application frequencies of plants, comparison with plant community diversity and suming up common examples of plant communities, laid the foundation for the study of representative plant communities.2. The small-scale plant communities have obvious temperature and humidify effect. The diurnal variations of temperature reduction and relative humidity increase were described as V-shaped curves, and both of them achieved extreme value at14:00-15:00h. There were obvious seasonal variations of temperature reduction and relative humidity increase. The seasonal order of temperature and humidify effect of plant communities was summer> autumn> spring> winter. Four types of plant communities had significant differences in temperature reduction and relative humidity increase. We finally concluded that multilayer plant community had the most significant effect on temperature reduction and relative humidity increase, followed by tree-grass plant community, palm mixed plant community and bamboo grove. The results showed that the planner should choose multilayer plant community and pay attention to the structures of plant communities and the combinations of trees, shrubs and grass to maximize the temperature and humidify effect of microclimate.3. It was clearly showed that there were correlations between temperature and humidify effect of small-scale plant communities and characteristics of plant communities (canopy density, canopy area and tree height). The equations of linear regression for temperature reduction (△T) and relative humidity increase (△H) were established, which not only can be used as quantitative analysis tool to estimate ecological benefits of plant communities in temperature and relative humidity, but also to predict the temperature and humidify effect of quasi-plant communities in the process of urban greening:△T=-2.973+0.041canopy density (%)+0.032canopy area (m2)-0.025tree height (m)+0.027solar radiation (mol m-2s-1)(R2=0.976)△H=1.786+0.026canopy area (m2)+0.025canopy density (%)+0.047tree height (m)+ 0.014solar radiation (μ mol m-2s-1)(R2=0.966)4. Plantscapes had positive psycho-physiological influence on human, which not only can decrease participants’ blood pressure and heart rate, increase galvanic skin response and result in more a waves and less β waves, but also can reduce the degree of stress and anxiety of participants and enhance vigour. Multilayer plantscape was the most effective followed by Palm mixed plantscape and tree-grass plantscape, and bamboo grove was the least effective. Jn small-scale plantscapes, the designers should pay more attention to the structures and layers of plantscapes to help people achieve a relaxed psycho-physiological state.5. Plantscape and sound combinations had significant influence on human both physiologically and psychologically. In general, soothing music and birdcall could bring benefits to both mind and body of participants when viewing the same plantscape picture, whereas noise had negative effects on participants. We suggested that the plantscape planners should pay more attention to the role of sound and design plantscape with soothing music or birdcall to maximize the psycho-physiological effects of plantscapes.In this research, the temperature and humidify effect and the psycho-physiological influence of small-scale plant communities were studied. Based on the findings. we established regression model of temperature and humidify effect of small-scale plant communities. and refined audio-visual configuration mode of small-scale plantscapes to provide some guidelines and theoretical reference for designing scientifical plantscapes and building healthy and comfortable living environment.