Selection Of Greening Tree Pecies In Northern Cities Based On Comprehensive Service Function Evaluation

The traditional selection of landscaping tree species mainly considers its landscape service function and ignores the ecological service function.Nowadays,in order to improve the actual needs of urban environment,how to correctly select tree species and scientifically allocate them to give full play to their ecological service function in addition to landscape service function has become a key scientific problem to be solved.This project intends to take24 common greening tree species such as Cercis chinensis,Firmiana simplex,Cerasus jamasakura,Melia azedarach,Platanus orientalis,Sophora japonica,Koelreuteria paniculate,Acer truncatum,Acer buergerianum,Pteroceltis tatarinowii,Ginkgo biloba,Aesculus chinensis,Liriodendron chinense,Celtis sinensis,Ailanthus altissima,Pinus tabuliformis,Pinus bungeana,Cedrus deodara,Juniperus formosana,Sabina chinensis,Juniperus chinensis,Ligustrum lucidum,Magnolia grandiflora,Osmanthus fragrans in northern cities as the research object.Through field investigation,sampling and indoor test,Determine and obtain the landscape service of each tree species（index data of green quantity,green leaf stage and beauty）,And the evaluation of the ecological service function of street trees to the road（Water conservation,dust retention and noise reduction,cooling and humidification,carbon fixation and oxygen release capacity）index data.Combined with the principal component analysis method,the ecological and landscape service functions of street trees are evaluated comprehensively.The appropriate street trees can be selected according to local needs,and get the main conclusions:（1）The evaluation of landscape service function of Urban greening trees,from the data of individual service function,the larger tree species with green density（Leaf biomass per unit crown volume）include Magnolia grandiflora,Cedrus deodara and Juniperus formosana（222.2-253.6 g/m³）,the tree species with high aesthetic score are Cercis chinensis,Osmanthus fragrans,Cerasus jamasakura and Magnolia grandiflora（10.2-10.9 points）.The green leaf days of Platanus orientalis,Celtis sinensis,Sophora japonica are more than 220 days.According to the above survey data,the research tree species can be ranked by principal component analysis:In deciduous broad-leaved trees,in terms of road beautification and landscape characteristics,Platanus orientalis,Cerasus jamasakura,Ginkgo biloba,Melia azedarach,Cercis chinensis are the preferred tree species（F₁:0.42,0.21,-0.03,-0.06,-0.11）,Liriodendron chinense,Koelreuteria paniculate,Aesculus chinensis,Celtis sinensis,Sophora japonica are the secondary tree species（F₁:-0.18,-0.21,-0.31,-0.56,-0.58）,Acer buergerianum,Acer truncatum,Firmiana simplex,Ailanthus altissima,Pteroceltis tatarinowii are alternative trees（F₁:-0.59,-0.61,-0.63,-0.71,-0.83）.Among evergreen tree species,according to the comprehensive evaluation and ranking results of landscape service function,In terms of road beautification and landscape features,Osmanthus fragrans,Magnolia grandiflora,Ligustrum lucidum are the preferred tree species with high comprehensive evaluation（F₁:1.6,1.41,1.4）,Cedrus deodara,Juniperus formosana,Sabina chinensis are the secondary tree species（F₁:1.34,1.2,0.71）,Juniperus chinensis,Pinus tabuliformis,Pinus bungeana are the alternative tree species（F₁:0.45,0.22,0.01）.（2）The ecological service function of street trees plays an important role in the ecological restoration of urban roads,the single service function includes the tree species with strong dust retention ability of the leaves of the unit crown,such as Magnolia grandiflora and Platanus orientalis（32.0-39.0 g/m³）;Trees with strong carbon sequestration and oxygen release ability include Koelreuteria paniculata,Platanus orientalis,and Magnolia grandiflora（1000–1700g/m³）;Melia azedarach,Ginkgo biloba,Pinus bungeana,Sabina chinensis and Magnolia grandiflora significantly promoted the water conservation capacity of tree roots（14.32-18.44%higher than the control）,The tree species with strong noise reduction ability of green quantity per unit crown volume include:Magnolia grandiflora,Juniperus formosana,Juniperus chinensis,Cedrus deodara（10.2-13.2 d B/m³）;The tree species with strong transpiration cooling capacity per unit crown include:Magnolia grandiflora,Platanus orientalis,Cercis chinensis（1.92-2.48 g/m³）,According to the above survey data,the research tree species can be ranked by principal component analysis:In deciduous broad-leaved trees,Ranking results according to the comprehensive evaluation of ecological service functions,In terms of environmental protection and ecological capacity,the higher species of Platanus orientalis,Aesculus chinensis,Firmiana simplex,Ginkgo biloba,Koelreuteria paniculate are the preferred species（F₂:1.82,0.38,0.33,0.20,-0.08）,Liriodendron chinense,Cercis chinensis,Melia azedarach,Cerasus jamasakura,Ailanthus altissima are the secondary tree species（F₂:-0.09,-0.13,-0.21,-0.30,-0.30）,Sophora japonica,Celtis sinensis,Pteroceltis tatarinowii,Acer buergerianum,Acer truncatum are the alternative tree species（F₂:-0.41,-0.47,-0.66,-0.79,-0.9）;In the evergreen tree,according to the ranking results of comprehensive evaluation of ecological service function,Magnolia grandiflora,Sabina chinensis,Pinus tabuliformis have high evaluation and are tree species with strong ability to purify the environment and maintain ecology（F₂:1.42,0.43,0.32）,Juniperus formosana,Juniperus chinensis,Cedrus deodara have average ability（F₂:0.08,0.01,0.01）,while Osmanthus fragrans,Pinus bungeana,Ligustrum lucidum have the weakest ability（F₂:-0.16,-0.23,-0.84）.（3）Among the 24 species of trees studied,according to the survey of landscape services and ecological services,Platanus orientalis,Ginkgo biloba,Magnolia grandiflora are greening trees with good landscape and ecological services,Ligustrum lucidum,Osmanthus fragrans belong to landscape service function is ideal,but ecological service is not high,Firmiana simplex,Sabina chinensis,Pinus tabuliformis are greening tree species with ideal ecological service but low landscape service northern cities should choose suitable tree species according to their local needs.（4）Comprehensively consider the landscape service function and ecological service function of tree species,and comprehensively evaluate and screen tree species,In the deciduous broad-leaved tree,the landscape services and ecological services of tree species are considered comprehensively.The trees of Platanus orientalis,Aesculus chinensis,Ginkgo biloba,Sophora japonica,Cerasus jamasakura can be selected as the first choice for city greening（F:1.39,0.14,0.09,0.05,-0.02）.Firmiana simplex,Liriodendron chinense,Koelreuteria paniculate,Melia azedarach,Celtis sinensis can be used as secondary tree species（F:-0.03,-0.05,0.11,-0.11,-0.38）,and Cercis chinensis,Ailanthus altissima,Acer buergerianum,Pteroceltis tatarinowii,Acer truncatum can be used as alternative tree species（F:-0.4,-0.53,0.71,-0.76,-0.78）.Among evergreen tree species,Magnolia grandiflora,Osmanthus fragrans,Cedrus deodara can be used as the preferred tree species for urban greening（F:2.35,0.63,0.56）,Sabina chinensis,Ligustrum lucidum,Juniperus chinensis can be used as secondary tree species（F:0.46,0.25,0.12）,while Pinus tabuliformis,Pinus bungeana,Juniperus formosana can be used as alternative tree species（F:-0.06,-0.16,-0.21）.