Investigation And Comprehensive Evaluation Of Vertical Greening Plant Resources In Guangzhou

As the urbanization pace is accelerating,urban land resources are straining,green space is reducing,tall buildings are unimaginably boosting,as well as elevated roads and bridges are crossing everywhere,vertical greening has become the research focus of garden landscape application and also a hot topic among urban residents.Guangzhou,as the capital of Guangdong province,is a representative city in southern China.The vertical greening in Guangzhou has been put into use early,which that there were a lot of experiences and achievements on vertical greening.However,there are many key technical and development problems in the vertical greening application,such as less of the application of plant varieties,not widely area used,the technology system of landscape evaluation still unperfect and the high maintenance cost relatively.Therefore,in this paper,four old urban districts in Guangzhou,which of including Yuexiu District,Tianhe District,Liwan District,and Haizhu District,have been selected.There have been systematical studied on their vertical greening plant resources,configuration and selection,landscape application models and design,maintenance technology and landscape effect evaluation of vertical greening plants.So as to provide the vertical greening application technical reference for Guangzhou and even more south China.The research results show as follows:(1)By survey and statistical analysis on Yuexiu,Tianhe,Liwan and Haizhu in Guangzhou,the average rate of vertical greening was 75% among the 106 sites,of which Tianhe District has the highest application rate of 88.46%,The application rate in Liwan District is the lowest,at 66.67%.(2)There has been applied a total of 86 species of vertical greening plants from 72 genera,42 families in Guangzhou,including 45 herb plants,24 woody plants and 17 liana plants.The most commonly used families belong to Araceae and Liliaceae.The highest frequency of growing were the species as for Schefflera actinophylla,Bougainvillea glabra,Nephrolepis auriculata,Quisqualis indica and Epipremnum aureum.(3)Among the 106 sites in Guangzhou,scaffolding greening,bridge body greening and wall greening are the most popular vertical greening structure,and the application of column and slope greening are relatively rare.The plant cultivation forms mainly include hedge type,hanging type,climbing type,modular type,paving type and bag type,including11 hedge type,21 hanging type,35 climbing type,29 modular type,4 paving type and 6bag type.(4)The cultivation substrates used for vertical greening in Guangzhou include mixed substrates and natural soil substrates.the mixed substrate has been used widely,as which can meet the requirements of nutrient.The natural soil matrix,applied to those vertical greening in Zhongshan Seventh Road,Zhongshan Eighth Road,Wuyang Community,Fangcun Avenue and Tianhe Wetland Park.That has poor nutrients leading plants to grow bad.The water supply methods of vertical greening landscape in Guangzhou mainly include drip irrigation and drip arrow.The application of automatic drip irrigation with better effect on plants has been used more generally.(5)The results of the questionnaire survey show that ecological benefit has the largest weight of 0.2991 among the four-criteria layer elements,while Resistance capacity has the smallest weight of 0.2116.The weight values of 14 evaluation index factors showed as follow: Ecological adaptability>Conservation cost>Landscape coordination>Planting cost>Color richness>Dust retention ability>Drought tolerance>Resistance to diseases and insect pests>Depression density>Ability of anti-pollution>Ability of noise reduction>Species diversity>Water resistance>Ability of local microclimate improvement.Ecological adaptability has the maximum proportion,which is 0.1446,while the weight value of ability of local microclimate improvement is the smallest,which is 0.0377.(6)Using the analytic hierarchy process to evaluate 22 vertical greening landscapes in this paper,the result of comprehensive evaluation was all scores more than 3 points,including 8 Grade I and 14 Grade II.It shows that the quality of the vertical greening landscape in Guangzhou is pretty high and the landscape effect is pretty good.Thinking about in vertical landscape type ways,there were one of the 8 Grade I landscapes contain applied in road construction,three of them applied in park constructions,and four of them applied in shopping malls constructions.Which indicates that the vertical greening at shopping malls and parks constructions had better landscape effect,and bad landscape effect in road constructions.The vertical greening landscapes with great effect commonly showed well growth of whole plants,high degree of coverage,rich colors,and coordinating the sketches,lights and the land environment well.Moreover,which usually had good aesthetic feelings of composition,well ecological benefit and high landscape degree.The vertical greening landscapes with poor visual effect usually had poor whole plants growth,barren varieties and monotone colors,which do not present the diversity of plants and landscapes.(7)According to the results of questionnaire survey on vertical greening,that 103 people completed,69.9% of people strongly supported the development of urban vertical greening,28.16% of people support it,0.97% of people do not care about the vertical greening,and 0.97% of people do not support it.The result showed that people generally holds a favorable attitude towards the development of vertical greening,and vertical greening deserves further study and positive guiding.