Construction And Application Of Ecological Suitability Evaluation System On Costal Salinity Tolerant Afforestation Tree Species

Nowdays, landscaping in new cities of China's east coast is facing a common problem. The high salinity of soil is making landscaping very difficult because of the shortage of suitable afforestation tree species. This study built an ecological suitability evaluation system for salinity tolerant afforestation tree species using analytic hierarchy process. Moreover, taking the demonstration in Shanghai Lingang Harbor City as an example, this study put the evaluation system into practice. The main conclusions are as follows:1An ecological suitability evaluation system for salinity tolerant tree species was built, which was composed of survival index, growth index, and resistance index.2Application of evaluation system1) Survival index:23tree species had full survival index(zero mortality rate).7tree species including Quercus virginiana, Diospyros morrisiana, Viburnum odoratissimum, etc. had low survival index.2) Growth index:Robinia pseudoacacia, Melia azedarach, and Cercis chinensis had the biggest hight and width growth in both year one and year two. Broussonetia papyrifera, Clerodendrum bungei, and Euonymus maackii had much bigger growth in year two than in year one. Generally, grow protential in year two was bigger than year one. Through ranking and dendrogram, in both years, growth index of category arbor and category small arbor or shrubs were devided into four groups seperately. The results showed that Robinia pseudoacacia was ranked first respectively showing strong growth adaptability. Pyrus betulaefolia however was ranked the last respectively showing weak growth adaptability. Other tree species changed in ranking and grouping, which showed the difference during the two year's growth.3) Resistance index:Most trees had insect attack. Leave eating, piercing sucking, and borer insects had the most obvious damage. There were more insect species in the second year. Because of the drought in year one, most tree species were under water and salinity stress. Among them, Magnolia liliflora, Pyrus betulaefolia, and Diospyros morrisiana had the lowest endurance against water and salinity stress. Water stress was decreased largely during the second year, therefore each species proformed better. However6species including Magnolia liliflora, Pyrus betulaefolia and Diospyros morrisiana still showed burnt in leaf or leaf top,which showed low endurance against water and salinity stress. Shanghai was hit by typhoon in both years. In the first year, most species were recorded in the situation of lodging, incline, and broken branches, which showed a low wind resistance. In the second year, there were no lodging witnessed, but more serious incline. Through ranking and dendrogram, in both years, resistance index of category arbor and category small arbor or shrubs were devided into three groups seperately. Ilex rotunda was ranked first in both years showing strong resistance. The ranking of Broussonetia papyrifera increased largely in the second year, the resistance of which became stronger. Ternstroemia gymnanthera and lex integra ranked high in both years, which showed a relatively strong resistance. Diospyros morrisiana and Magnolia liliflora ranked low in both years which showed a rather low resistance.Through comparation and evaluation the survival index, growth index, resistance index and ecological suitability index of30introduced afforestation tree species, the study slected species with high ecological suitability. Robinia pseudoacacia, Melia azedarach, Cercis chinensis, Ternstroemia gymnanthera, Amygdalus persica and Cercis chinensis are of high ecological suitability, which could be recommened strongly as key afforestation tree species. Toona sinensis, Sapindus mukorossi, Populus deltoides cv. Zhonghuahongye, Koelreuteria bipinnata, Ilex rotunda, Sapium sebiferum, Ilex integra, Euonymus maackii, Rhaphiolepis umbellate and Clerodendrum bungei are of relatively high ecological suitability, which could be recommened as afforestation dominate tree species. Cinnamomum japonicum, Quercus virginiana, Salix sp., Pyrus betulaefolia, Photinia serrulata, Ligustrun lucidum, Distylium buxifolium, Viburnum odoratissimum, Diospyros morrisiana, Eurya emarginata and Magnolia liliflora are of poor ecological suitability, which would not be recommended. Broussonetia papyrifera and Ailanthus altissima still need further observation and measurement. The results can provide both theoretical and practical reference for further afforestation tree species selection in this area.