Research On Evaluation Of Health And Safety Of Trees In Urban Road Green Space

On August 18,2018,typhoon "Rumbia" entered Anhui Province,causing severe wind damage in many Province of Anhui,among which strong wind and heavy rainfall caused many sections of trees in Ma'anshan City to fall,incline and break and traffic congestion in many sections.Through the statistical investigation of wind damage,health and safety of57 garden trees in 82 road green space of the main urban area in Ma'anshan City,this paper creatively combines delphi method and fuzzy priority ranking method to screen evaluation indexes,and constructs a comprehensive evaluation system of tree health and safety based on analytic hierarchy process method and fuzzy membership function method.And cluster analysis method is used to grade the evaluation results.According to the comprehensive score,cluster comparative analysis is carry out to explore the relationship between the health and safety of different trees in the road green space of Ma'anshan City.One-way ANOVA method and Duncan test method are used to analyze the significant difference of tree health in different road areas of the main urban area in Ma'anshan and the methods timely and accurately reveal the characteristics and influencing factors of the healthy change of trees,providing a certain reference for the maintenance and management of trees in Ma'anshan at this stage.The main results are as follows:(1)By delphi expert consultation method and fuzzy priority ranking method,some health and safety indexes are deleted and registered.(2)The indexes with higher weight of tree health in road green space of Ma'anshan are respectively tree vigour(Wi = 0.1716),inclination(Wi = 0.1025),tree crown density(Wi= 0.0869),exposed state of trunk xylem(Wi = 0.0868),ratio of tree crown to withered shoot(Wi = 0.0709)and tree crown inclination(Wi = 0.0612).The indexes with higher weight of tree safety are wood characteristics(Wi = 0.1615),inclination(Wi = 0.1277),height diameter ratio(Wi = 0.0757),oblique opening of trunk(Wi = 0.0730),decay ratio of tree trunk basis(Wi = 0.0644)and root type(Wi = 0.0481)indexes.(3)The results of wind damage cluster classification and tree safety cluster classification by fuzzy membership function method are basically the same in the road green space of the main area of Ma'anshan,The results of 37 kinds of trees health cluster classification by fuzzy membership function method and trees safety cluster classification by fuzzy membership function method are completely the same,15 kinds of trees cluster classification results are similar,5 kinds of trees cluster classification results are opposite.(4)The classification of healthy and safe trees in the main urban area of Ma'anshan can be divided into 4 grades,Among them,there are 11 kinds of I class trees,which can be used as the key tree species of road green space in Ma'anshan.There are 18 kinds of II class trees,which can be used as the backbone tree species of road green space in Ma'anshan City;There are 12 kinds of ? class trees,which are not recommended for large area selection;There are 16 kinds of ? class trees,which are not recommended for selection on tree species arrangement.(5)One way ANOVA method and Duncan multiple comparison method are used to analyze and compare the significant differences of the same tree in different road areas,and the results show that there are no significant difference(P > 0.05)except for the average growth competition index,the average first-class dead branches index,the average exposure of tree trunk xylem index,the average root damage index,the average proportion of nutrient in and out of the space index,the average surface water accumulation index.The other 17 indexes show significant difference(P < 0.05).