Study On Selection And Application Of Wind-resistant Garden Trees In Coastal Area Of Shenzhen

Shenzhen is a key coastal city in the southeast coast of China,and is also a city with high frequency of typhoon disaster.For the reason,the wind damage and morphological wind resistance indexes of 41 kinds of road trees and 51 kinds of common garden trees in Qianwan area of Shenzhen after being hit by super typhoon Mangkhut in 2018 were investigated.And using the expert consultation method to determine indicators.Two kinds of comprehensive evaluation systems were constructed by using analytic hierarchy process(AHP)to quantify and weight the index measured,and then the comprehensive evaluation method was used to rank the characteristic indexes of plant damage caused by wind and the morphological indexes of wind-resistant plants by fuzzy membership function.The clustering results were compared and analyzed according to the total value of the comprehensive score of the characteristic index of wind damage and the total value of the subordinate function of the morphological wind resistance index to explore the wind resistance of the trees in the road and the park.In addition,the relationship between tree damage characteristics and plant morphology was verified by the results of wind damage evaluation of garden trees to establish the morphological index prediction system of plant wind resistance.The aim is to provide a method to verify the wind resistance of plants for the future,and to select garden trees with strong wind resistance for planting on the road or in the park.Wind-resistant landscape construction needs a scientific and complete process,from the planning and design,construction and maintenance,to establish a set of garden plant application management system.By recommending the application mode of garden trees with wind-proof function and landscape requirements to put forward the application of wind-resistant landscape planting,the construction of typical landscape features and plant collocation Suggestions under the premise of wind resistance,and the cultivation and restoration ideas of road green belt after the disaster.It aims to provide some reference for coastal city construction and plant wind-proofing and disaster reduction.The main research results are as follows:(1)Five evaluation indexes were determined for the wind damage characteristics of garden trees in Qianwan area:trunk fracture rate,trunk lodging rate,minor branch fracture rate,trunk tilt rate and blade tear rate.Ten evaluation indexes of wind resistance morphology of garden trees in Qianwan area were determined:crown height ratio,chest diameter,crown width,wind area of plants,height of plant center of gravity,bendingstrength,compressive strength along grain,crown shape,leaf layer status and root status.(2)The total value of the comprehensive score of the characteristics of wind damage and the total value of the subordinate function of morphological wind-resistance of garden trees are basically consistent with the clustering analysis results,and the wind-resistance of garden trees can be predicted by the plant morphological indicators.Through the analysis of clustering results of the two evaluation systems,it is found that 17% garden trees have the same classification results,76% have similar classification results,and 7% have completely opposite classification results in the road green land.It is also found 10%garden trees have the same results,73% close and 17% opposite in the park green space.(3)The landscape tree in Qianwan area according to the results of hierarchical clustering was divided into wind resistance Ⅰ,Ⅱ,Ⅲ grade,and carries on the wind resistance.Among them,there are 13 kinds of the wind resistance Ⅰ level,such as Bismarckia nobilis,Wodyetia bifurcata,Ormosia pinnata,Syzygium samarangense,Myrica rubra,etc.,for the wind-resistant tree,not easy to break off and lodging;There are 26 kinds of tree in wind resistance level Ⅱ,such as Roystonea regia,Phoenix canariensis,Mangifera persiciformis,Ficus microcarpa,Terminalia mantaly,etc.,for the average wind resistance;There are 11 kinds of tree in wind resistance level Ⅲ such as Bauhinia blakeana,Handroanthus chrysanthus,Cleistocalyx operculatus,Sterculia lanceolata,Jacaranda mimosifolia and so on,the wind resistance performance is relatively poor,suggest choose in specific environmental conditions or to use less.(4)Establishing an application management system of garden plants from the aspects of "planning,design,construction and maintenance",which can be used to guide the greening construction of coastal areas.In terms of planning and design,it is necessary to select and configure different wind-resistant tree species according to geographical environment.In terms of construction,it is necessary to pay attention to the key points in the construction process of afforestation.In terms of maintenance,it is necessary to do a good job in the early survival maintenance and the later conventional maintenance management.(5)There are several ways to combine the windbreak function and landscape requirements in the road green space and the park green space.The first is to form five application models of plant planting in the protected forest area,windward surface,leeward surface,tuyere area and sheltered area.Under the premise of wind resistance,typical landscape types should be created,including green shade,coconut wind and sea rhyme,color contrast,rich seasonal phase,and fragrant five types of landscape.Thirdly,according to the characteristics of the road green space and the park green space affected by thedisaster,the idea of planting and restoration was applied to restore the green space belt after the disaster by "retaining plants,replacing plants and retreating plants".