The Study On Woody Plant Diversity Of Park In Yongchuan

In this paper,the parks of Yongchuan district are taken as the research object.We made a field investigation on the composition of woody plant species and vegetation types in twenty-two parkland of which were concluded in the comprehensive parks,community parks,theme parks and roadside greenbelts,analyzed the composition of woody plant species and the diversity of the vegetation type,growth form and woody plant species,discussed the relationship of woody plant diversity,parkland types and parkland area.The main results are as follows:(1)The results showed that there were 155 woody plants species,which belonged to 131 genera and 62 families in parkland of Yongchuan district.In those plants,there were 97 arbor species,53 shrub species,5 bamboo species.Among them,the advantage genera are Rosaceae(12 species),Palmae(9 species),Euphorbiaceae(7 species),Oleaceae(7 species).From the aspects of the plant application frequency,the low frequency(<2%)plant species were dominant(71%).The most frequently used plants were Osmanthus fragrans Lour.(21%),Ginkgo biloba Linn.(13%),Cinnamomum japonicum Siebold(12%),Ficus virens Aiton(11%),Pittosporum tobira(Thunb.)Ait.(20%),Ligustrum x vicaryi Rehder(16%),Loropetalum chinense varn rubrum Yieh(15%),and Camellia japonica Linn.(12%).The proportion of native plants in the park green space was 63%,lower than the native woody plant index(≥ 0.7)of the "Urban Landscape Evaluation Standard"(GB/T 50563-2010).It is needed to improve the application level of native woody plants in the parks.(2)Evergreen broad-leaved forest,deciduous broad-leaved forest and mixed evergreen and deciduous broad-leaved forest are the three main vegetation types above the eight vegetation types in parklands of Yongchuan district.The abundance of vegetation types of comprehensive parks,community parks and theme parks is 5.75,5.67 and 5.25,much higher than roadside greenbelts which is only 3.The diversity index and dominance index has significant difference among different vegetation types in different parklands.Comprehensive parks has the highest diversity index as 2.17,while roadside greenbelts has the lowest as 1.12.And theme parks has the highest dominance index as 0.65 while comprehensive parks has the lowest as 0.16.This suggests that comprehensive park has the highest level of vegetation diversity.Through the statistical analysis,the diversity of vegetation types has a significant positive correlation with the area of park green space.(3)There are 15 growth forms of the park woody plants in Yongchuan district.Evergreen broad-leaved trees,deciduous broad-leaved trees,evergreen broad-leaved shrubs and deciduous broad-leaved shrubs are wide application in every type of parklands.The diversity of woody plant growth form of comprehensive parks,community parks and theme parks were very high:the richness of their growth forms is 9.00,9.00 and 9.25;the diversity index of their growth forms is 2.46,2.58 and 2.60.The two indices of woody plant form of roadside greenbelts are significantly lower:the richness of its growth forms is 6.36,and the diversity index of its growth forms is 2.25.Through the statistical analysis,the correlation of the growth form diversity index and the area of park green space.is not significant.(4)The species richness of woody plant in parklands of Yongchuan is:shrub layer(3.06)>tree layer(2.63).Among them,the parkland type of which has the highest species richness of tree layer and shrub layer is comprehensive parks;the species richness of tree layer and shrub layer of the roadside greenbelts is the lowest,respectively 2.3 and 2.81.Evenness of woody plants of each type parkland are high(between 0.57 to 0.77),and the tree layer>shrub layer.The highest species diversity of woody plant in parklands of Yongchuan is comprehensive parks,of which the species diversity indices of the tree layer and the shrub layer are 0.79,0.78.The species diversity indices of the tree layer and the shrub layer of the roadside greenbelts are the lowest,respectively 0.67,0.78.In conclusion,the woody plant species diversity of the comprehensive parks is the highest,and roadside greenbelts is the lowest.Through the statistical analysis,the correlation of the woody plant diversity index and the area of park green space is not significant.