Research On Risk Prediction Static Model Of Trees' Damage Caused By Strong Wind In Typical Streets Of Guangzhou

In recent years,typhoons have seriously damaged the urban vegetation in Guangdong,Hong Kong and Macao Bay area.The wind damage of trees in urban streets is stem break or uproot,which is destructive to the surrounding buildings and traffic infrastructure.However,due to the complex strong wind environment of urban streets,it is difficult to measure and simulate,the individual morphological differences of trees in urban streets are difficult to abstract,and the mechanical mechanism of trees'wind damage is not mature.Relevant scholars prefer to do research on trees's species wind resistance classification based on statistical analysis of post disaster damage data,rather than building a universal mechanical prediction model of trees'wind damage to prevent wind disaster and improve the ability of street trees to resist wind damage.This kind of research starts from improving the wind resistance of economic forest,and there are few similar researches on trees in street environment.The core content of paper is to build a static prediction model for the risk of strong wind damage of non centrosymmetric trees in typical streets of Guangzhou.In order to improve the wind resistance ability of urban street trees,a comprehensive and detailed literature research was carried out.In this paper,33 trees in De Zheng Middle Road(section)and its interior were selected as the research objects.Based on the theories and technologies of tree mechanics,tree measurement,plant phenotype,near earth meteorology and computational fluid dynamics,a quantitative function model was established to evaluate the ability of trees to resist strong wind damage(trunk base breaking and uproot)through critical wind speed(CWS).From the functional model involving dozens of tree wood mechanics,ground and underground morphological characteristics(independent variables)derived to the indirect factors(selection of trees'species and control of trees'age,trees'spatial distribution and site conditions,daily pruning and plant protection)influencing the independent variables,the contribution(importance)of each(class)factor to the strong wind resistance ability of street trees was evaluated based on the comprehensive model and experience From the perspective of landscape architecture,this paper puts forward targeted planning and design and engineering technical suggestions.Main conclusions:the prediction results of 33 trees in De Zheng Middle Road(section)are similar to the actual wind damage;In almost all cases,the critical wind speed of stem base breaking is higher than the critical wind speed of uproot(U(10)_SB>U(10)_UR).In most cases,the position of the root-soil plate in all directions tends to be at the base of the trunk or at the far end of the root.The factors(model independent variables)that directly affect the ability of trees to resist strong wind can be roughly divided into(a)wood mechanical characteristics(b)above ground morphological characteristics(c)underground morphological characteristics,and the contribution of(b)(c)to the ability of trees to resist strong wind is greater than(a).Because of the difference of mechanism,uproot is more sensitive to factors related to canopy quality than stem base break.Three types of indirect factors include(A)selection of trees'species and control of trees'age(B)trees'spatial distribution and site conditions(C)l daily pruning and plant protection.When uproot is the main wind damage type of street trees(Guangzhou and other cities in South China),"non tree species'conditions"is relatively more important.