Comparison in drought resistance of tree species in coastal protective forests

Four tree species(Robinia pseudoacacia, Quercus acutissima, Rhus typhma, Albizia kalkora) and four shrub species(Pyrus betulaefolia, Elaeagnus angustifolia, Lespedeza bicolor, Amorpha fruticosa) were selected in this research, and their leaf water potential, transpiration rates and environmental factors were measured in Jiaonan City, Shandong Province.The results indicate that:1) the order of the daily average transpiration rates of the trees is A.kalkora < R.pseudoacacia < R.typhma < Q.acutissima, and that of the shrubs is A.fruticosa <L.bicolor<E.angustifolia<P.betulaefolia;2) the order of the daily average leaf water potential among trees is A.kalkora < R.pseudoacacia <R.typhma < Q.acutissima, while that of the shrubs is A.fruticosa <L.bicolor<E.angustifolia<P.betulaefolia;3) the biggest water use efficiency is A.kalkora for trees and A.fruticosa for shrubs;4) comparison of drought resistance indicates that A.kalkora > R.pseudoacacia>R.typhma > Q.acutissima for trees, while A.fruticosa >L.bicolor> E.angustifolia >P.betulaefolia for shrubs in general.