Research On The Shading Effect Of Common Street Trees In Jinan

With the development of the city,the effect of urban heat island is becoming more and more serious.The comfort of pedestrians and non motor vehicle drivers is low in summer.People's demand for good road space environment is more and more urgent.Road green space is an important green infrastructure of a city,which plays an important role in creating a good urban ecological environment,building a beautiful urban environment and building a comfortable outdoor space for citizens.Street trees are an important part of urban road greening,which can block the strong direct sunlight in summer,improve the urban microclimate,shade the road space and reduce the temperature,purify the air,fix carbon and release oxygen,absorb dust and harmful gases to reduce air bacteria,reduce noise,etc.At present,most researches focus on the selection of tree species of street trees,focusing on the ecological role of street trees,or the analysis of the landscape effect of street trees,but for the shade effect of street trees,only as a general principle and ignored,it is not the focus of research.It is known that street trees can provide shade,but whether the shade effect of different street trees is the same and which street tree has better shade effect needs quantitative research.In this study,Fatong,Guohuai,catalpa,ash,dried willow,Melia azedarach and Ligustrum lucidum were selected as the research objects,and the research environment of the research objects was determined through field investigation.The temperature,humidity and illuminance of all light,temperature,humidity and illuminance under shade conditions,tree height,crown width,crown height,branch point height and DBH were measured to explore the shading rate,cooling rate,humidification rate,shade quality and comprehensive shading effect of seven species of roadside trees under similar conditions,and the comprehensive shading effect of seven species of roadside trees was compared and analyzed to obtain seven kinds of sidewalks The conclusion of the comprehensive shade effect of tree plants was made,and the application of the conclusion was discussed.The paper is divided into six parts:The first chapter is the introduction.This paper expounds the purpose of the research,discusses the importance of the research,classifies the research results and the knowledge system involved in the research,further discusses the details and research methods of the research,and explains several key points of the research.The second chapter is about the determination of the research site,including the geography,the road,the climate and the application of the roadside trees.Through field investigation and literature research,the selection principles of research objects are determined,which are respectively located in Liuzhuang road Zhangzhuang section of Jingshi Road,Lashan overpass Bayi overpass section of Jingshi Road,West 2nd Ring Road Binzhou section of Weihai Road,West 2nd Ring Road kelangshan section of liuchangshan Road,East Zhangzhuang road lashanhe road of Jingshi Road,West Zhuanshan road and West 2nd Ring Road section of Jingliu road Zhangzhuang road Location.In the third chapter,the research objects and data were measured,and the research tree species were screened,including Fatong,Guohuai,catalpa,ash,dry willow,Melia azedarach and Ligustrum lucidum.The time,method and main content of data collection were defined,and the related index definition and calculation method of shade effect were expounded.In the fourth chapter,the data analysis of individual plant shading effect is carried out.The data of sample plants are measured and calculated.The differences of shading rate,cooling rate,humidification rate,shade quality and comprehensive shading effect of different tree species are analyzed and sorted.The results showed that the order of daily average cooling rate from high to low was catalpa tree,dry willow,Fatong tree,Ligustrum lucidum,Melia azedarach,Sophora japonica,and ash.The order of daily average shading rate from high to low was Melia azedarach,Fatong tree,Sophora japonica,ash,Ligustrum lucidum,dry willow and catalpa tree.The order of daily average humidification rate from high to low was Fatong tree,dry willow,catalpa tree,Melia azedarach,ash,Sophora japonica,and ash.The order of comprehensive shading effect from high to the bottom is Fatong,Melia azedarach,Salix mandshurica,catalpa,Sophora japonica,ash and Ligustrum lucidum.Chapter ? correlation analysis of observation indexes and shading effect The regression analysis of shading rate,cooling rate,crown width and comprehensive shading effect,the correlation analysis of humidification rate,crown height,branch point height,DBH and shading effect,the correlation analysis of human comfort regulation rate and humidification rate,shade quality and shading effect,the results show that crown width has the greatest impact on the shading effect of street trees,followed by cooling rate and shading rate;street trees The higher the humidification rate,the better the comprehensive shading effect;the higher the crown height,the higher the branch point and the larger the DBH of the street tree,the better the comprehensive shading effect;the humidification effect of the street tree will not increase the human body's heat sensation;the higher the shade quality of the street tree,the better the human body's comfort regulation rate.The sixth chapter summarizes and discusses the main conclusions and applications.This paper analyzes and compares the comprehensive shading effect and related variables of seven species of street trees,and discusses their application in the construction and design of road green space.