Study On General Indicator System And Quantitative Technology For Assessment Of In-forest Landscape Quality Of Urban Forest

Urban forest is an important part of urban green space.Scientific evaluation of urban forest quality is a prerequisite for determining a reasonable urban forest structure and scientifically constructing urban forest.At present,there have been a lot of studies on the evaluation of urban forest landscapes,but there are few discussions on the general evaluation techniques of various types of urban forests.In this study,four types of urban forests,including scenic-recreational forest of urban park and urban forest of residential areas which are in urban areas,scenic-recreational forest of country park and scenic forest of suburban mountainous areas which are in suburbs,were used as research objects,and evaluation indicators were selected on the stand scale.Different methods such as scenic beauty estimation method,expert consultation method and correlation coefficient method were used to evaluate the in-forest landscape quality of urban forest and evaluation indicators were selected.A regional universal in-forest landscape quality evaluation index system of urban forest was constructed,and the in-forest landscape quality was classified,in order to provide technical support for urban forest structure regulation,management and production practice.The main research conclusions are as follows:?1?The relationship between stand structure and scenic beauty of in-forest landscape is complex.The correlation between different stand structure indicators and scenic beauty of in-forest landscape of urban forest is different,and the difference significance between different scenic beauty grades is also different.A total of 16 stand structure indicators have a significant or extremely significant correlation with scenic beauty of in-forest landscape,and a total of 10 stand structure indicators have significant or extremely significant differences between different scenic beauty grades.?2?Fifteen evaluation indicators were selected based on four types of urban forest,and the evaluation indicator system of in-forest landscape quality of urban forest was constructed by factor analysis method.The linear stepwise regression and the quadratic polynomial stepwise regression were used to construct the general quantitative model of the scenic beauty of in-forest landscape.The linear stepwise regression model?SBE₁=20.797+2.317U₁+10.171U₂-15.925U₃?is effective and its R²=0.454,which can predict the scenic beauty of in-forest landscape to a certain extent.?3?The scenic beauty?SBE?and the comprehensive quality index of forest structure?U?were used as clustering index to systematically cluster the in-forest landscape in different types of urban forests.The in-forest landscape was divided into four grades by TOPSIS method,and the order from high to low is optimal-quality landscape,high-quality landscape,intermediate landscape and low-quality landscape.The indicator characteristics of the optimal landscape in different types of urban forests are not exactly the same.?4?The main color patch indexes that affect the in-forest landscape quality of various types of urban forests are different.According to the types of in-forest color patches,a certain proportion of buildings and tree crown is conducive to the improvement of in-forest landscape quality,while a large number of branches and dead branches have a negative effect on the in-forest landscape.The stand structure affects the in-forest landscape quality by affecting the spatial distribution characteristics of in-forest color patches.