Evaluation Of Shanghai Public Greenbelt Plant Communities And Optimize On Structure

This paper studied on the public greenbelts in Songjiang District of Shanghai,took field survey on 10 main public greenbelt plant communities in newly built Songjiang,summed up characteristics such as the species composition of plant communities,Hierarchical structure and so on.It also took 6 plant communities with similar size and similar environment to comprehensively appraise the landscape and ecology.The study based on SBE method and AHP method to appraise ornamental landscape,quantitative experiment on main ecological functions of each plant community.Combined landscape effectiveness with eco-efficiency of plant community to synthetically arrange them and get the best configuration mode and to make recommendations to optimize landscape.The following conclusions gained:1.In the 10 plant communities be surveyed there are 68 plant species,which belonged to 60 genera and 49 families.The plant species of highest frequency of occurrence are: Cinnamomum camphora,Ligustrum lucidum,Prunus cerasifera,Malus halliana,Hypericum monogynum,Camellia japonica,Oxalis corniculata,Iris tectorum.In the comprehensive evaluation of the 6 plots there are 45 species,which belong to 31 genera and 36 families. Cinnamomum camphora has biggest frequency for 100%,the frequency of Oxalis corniculata, Iris tectorum is 67%,and the frequency of Fatsia japonica,Euony musmaackii,Sabina chinensis cv.kaizuka is 50%.2.The results of SBE method to evaluate plant communities:the most favorite spring landscape is D3(Cinnamomum camphora-Michelia figo+Malus halliana+Camellia japonica-Hypericum monogynum+Euony musmaackii-Oxalis corniculata),the most favorite summer landscape is D6(Cinnamomum camphora+Albizzia julibrissin+Firmiana simplex-Osmanthus fragrans+Prunus cerasifera-Pyracantha fortuneana-Iris tectorum+ Oxalis corniculata),the most favorite autumn landscape is D4(Metasequoia glyptostroboides-Ligustrum lucidum-Cercis chinensis-Euony musmaackii-Oxalis corniculata),the most favorite winter landscape is D1(Sapindus mukorossi-Podocarpus macrophyllus+Prunus cerasifera-Pittosporum tobira-Iris tectorum).The best plant community comprehensive configuration mode is D3 whose visual effects are highly praised by the judges.D5(Cinnamomum camphora-Prunus lannesiana-Fatsia japonica+Aucuba japonica var.variegate-Ophiopogon japonicus) with the lowest points is the worst landscape and is not recognized by the public.3.The results of AHP method to evaluate plant communities:The total order of effectiveness of community landscape is D3＞D6＞D1＞D4＞D2＞D5.In appearance characteristic evaluation factors the most important value is color collocation,whose weight is 0.4690.In landscape diversity evaluation factors the most important value is seasonal variation, whose weight is 0.5055.The study shows that the SBE method and the AHP method have the same result in landscape evaluation.4.Difference in temperature in each plant community is highest in July and lowest in June, which is consistent with the actual temperature change of June,July and August.Plant communities have the most obvious cooling effect at 14:00 and 10:00 in a day which is 5.1℃and 4.6℃,and has the lowest cooling effect at 16:00 which is 2.8℃.5.The highest humidity difference of each plant community is in July and gradually reduces in June and August.Plant communities have the most obvious humidification at 8:00 and 14:00,and the increasing of relative humidity is 9.3%and 9.2%.6.At 12:00 anion concentration difference reaches the max in and outside the plant communities,and at 16:00 it is the lowest.Moreover the concentration difference turns from increase to lower showing to a parabola.7.The highest comprehensive evaluation total score plant community on landscape and ecological benefits is:Cinnamomum camphora-Michelia figo+Malus halliana+Camellia japonica-Hypericum monogynum+Euony musmaackii-Oxalis corniculata.