Study On The Structure,Species Diversity And Spatial Differentiation Of Notable Trees In Hefei City

The cultivation history of urban trees has been a key natural component of urban ecosystems for thousands of years.It is an important green infrastructure for cities and an important link between urban residents and nature.However,due to the competition of artificial buildings and hard surfaces,polluted air,water,soil and other factors,it is difficult for urban trees to exert their biological potential.Therefore,many scholars have proposed that the protection and management of rare and notable trees in cities should be strengthened,their health status should be emphasized and their landscape ecological value should be exerted.In this study,the city in Hefei was used as a research area to study the structure,diversity and spatial distribution pattern of urban notable trees species.Based on the research of notable trees in domestic and foreign,this article investigates the notable trees of industrial district(Yaohai District)and Administrative District in Hefei,the identification of notable trees within one ring of main district in Hefei combining the identification index system of notable trees which was established by the team in the past,and finds the regulation of the structure,diversity and spatial distribution pattern of notable tree species in the city of Hefei,it reveals the formation mechanism of the notable trees in the city of Hefei.Research indicates:(1)The identification indicators of notable trees are divided into two parts:qualitative and quantitative.In this study area,there are 416 notable trees were identified,and 112 strains were identified within one ring of city in the previous one research.A total of 528 notable trees were identified,The number of notable trees assessed by qualitative indicators is much lower than that of notable trees assessed by quantitative indicators.The scores of urban notable trees with quantitative index scores are more significant in the low score range,and the number of notable trees in the high score range is less distributed,and the scores and quantities of notable trees in Hefei are generally presented with the score.The higher the scores are,the lower the distribution of notable tree numbers are.There are differences in the distribution of notable trees in the three urban areas.From high to low,they are Yaohai District(347 strains),the main urban district(112 strains)and the Administrative District(69 strains).Due to its rapid economic development and rapid urban renewal,the main urban areas are seriously damaged during the high-frequency urban renewal process,and the habitat of urban trees is highly narrow and tense,resulting in a small number of significant trees in the main urban area.Yaohai District is lagging behind the main urban area due to its economic development.Its urban renewal speed is slower than that of the main urban area.The early trees suffered less loss during the urban renewal process,and the trees have more sufficient growth space,resulting in a higher number of significant trees in the Yaohai District than the main urban area.In the future urban renewal construction,we should pay attention to the protection of the habitat and growth space of the original trees in the city,and minimize the loss of the original trees in the process of urban renewal,thus helping to avoid "planting trees without seeing green"and "I saw trees,no forests."(2)The 416 notable trees identified in this survey belong to 33 families,30 genera and 23 families.Among them,the most dominant species in terms of quantity,the highest value of the species are Platanus acerifolia,Cinnamomum camphora and Populus tomentosa,the relative abundance of 31.73%,15.87%and 6.63%;the most dominant position,the highest value of importance The family is of the genus Platanus,Lauraceae and Salicaceae.The Platanus acerifolia and the Cinnamomum camphora are all fast-growing fast-growing tree species,which meet the pursuit of the speed of landscaping in urban garden construction.Therefore,they are widely used.In urban garden construction,attention should be paid to the coordination of fast-growing trees and longevity trees.The proportion of the tree species is sustainable and ecological.The distribution of Salicaceae plants is mainly due to the fact that the tree species,especially Populus tomentosa,have been adapted to the climatic conditions between Hefei and Jianghuai since ancient times.It has a long history of planting in Hefei and is widely distributed.There are differences in the flora composition of notable trees in urban areas.Yaohai District has the most prominent tree species,followed by the main urban dictrict,and the Administrative District has the least tree species.Among the notable trees in Yaohai District,the species with the highest abundance,the most dominant position and the highest importance are the Platanus acerifolia and the Cinnamomum camphora,the Administrative District is the Cinnamomum camphora,the genus,and the main city is Pterocarya stenoptera.Among the three urban districts,the Yaohai District has the most distinctive trees,followed by the main urban ddisttrict,while Administrative District has the most distinctive trees.Further statistics show that the most common species of the genus Lauraceae in the prominent trees of the city in Hefei,followed by Leguminosae and Salicaceae.(3)More than half of the notable trees are distributed between 20 and 40 years,and with the age of the trees increases,the number of notable trees in the city shows a downward trend.The age distribution of notable trees has obvious differences among urban district.The distribution of notable tree species in the main urban district is the most uniform and the overall age is the highest.In the second Yaohai District,the urban age of the Administrative Districts is the most uneven,almost all concentrated.The distribution is in the low age range and the overall age is the lowest.Among the prominent species,the evergreen broad-leaved tree species accounted for 20.64%;the evergreen coniferous tree species accounted for 7.58%;the deciduous broad-leaved tree species accounted for 67.23%;and the deciduous coniferous tree species accounted for 4.55%.There are a total of 171 native tree species in the prominent trees of the city in Hefei,accounting for 32.39%of the total number of plants assessed;357 non-local tree species,accounting for 67.61%of the total number of plants.The native tree species accounted for 57.5%of the total number of prominent tree species in the city;17 species of non-native tree species accounted for 42.5%of the total number of tree species.The species of native trees in the prominent trees are more than the species of non-native species,which is consistent with the laws of regional plant growth.However,due to the large number of exotic tree species introduced in urban greening construction in recent years and the adaptability of some exotic tree species,it is determined that the number of native tree species in the dominant tree is far less than that of non-native species.(4)The average tree height of the prominent trees in Yaohai District is the highest(12.84m),followed by the main urban district,and the average tree height of the administrative strict is the lowest;the average diameter of the main trees in the main urban district is the largest(0.58m),followed by the Yaohai District,the government culture.The average area of the new area is the smallest;the Yaohai District has the largest canopy area(36,278.31 m2),followed by the main urban district,and the Administrative District has the lowest crown area.Further analysis found that there are also differences between the streets.(5)Among the five streets in Yaohai District of Hefei City,the average height of the notable trees in Changhuai Street was the highest(13.87m),followed by Tongling Road Street,Mingguang Road Street and Shengli Road Street.The average tree height of Sanli Street was the lowest.The largest average breast diameter of the significant trees is Changhuai Street(0.48m),followed by Shengli Road Street,Sanli Street and Tongling Road Street.The average tree diameter of Mingguang Road Street is the smallest.The area with the largest canopy width is Shengli Road Street(11610.87m2),followed by Mingguang Road Street,Tongling Road Street and Changhuai Street.Sanli Street has the smallest canopy area(6)Analysis of the diversity and spatial distribution pattern of notable tree species shows that the main urban district has a long history and mature greening,and its tree species diversity index is the highest.The Administrative District is relatively new,and it is the political,economic and cultural center of Hefei.The planning of urban district is more scientific and modern.The landscaping construction also pays more attention to the diversity of plant varieties,and the diversity of significant tree species in the area is only second in the main city.Among the three urban districts,the Yaohai District,which is the industrial district of Hefei,has the lowest species diversity.Different from the distribution of species diversity index,the distribution of notable tree species in the Administrative District is higher than that in the main urban area,and the species uniformity in the Yaohai District is the lowest among the three urban districts.(7)The distribution of notable trees in the city of Hefei is mainly concentrated in urban roads,residential land and parks,and there are differences between urban areas.The most prominent place in the Yaohai District is the urban road.The most prominent location of the city in the new district of the government culture is the residential land,while the most prominent place in the main urban area is the park.