Study On Ecological Adaptation Of Colored-leaf Trees In Beijing

In this paper, we investigate and collect the excellent colored-leaf trees resources in Beijing. We have built a comprehensive evaluation model of colored-leaf trees’ornamental value by the application of AHP, and have evaluated58kinds of colored-leaf trees with this model. We have made a comprehensive evaluation of colored-leaf trees’phenology, heat resistance, cold resistance and pest and disease resistance ability according to their biological characteristics and ecological characteristics. This would provide a scientific theory for the colored-leaf trees’selection and its landscape screening application in Beijing. The main findings are as follows:1. According to the size of the comprehensive evaluation value, we have used AHP to evaluate58kinds of colored-leaf trees and dividing them into four grades. I level (>3.7):higher value of integrated application types, a total of8kinds; II level (3.3to3.7):high value of integrated application species, a total of29kinds; III level (3.0to3.3):the average value of integrated application species, a total of13kinds; IV level (<3.0):the lower value of integrated applications, a total of8kinds.2. Through morphological observation method, we have evaluated the ecological adaptability of33kinds of colored-leaf trees. By observating the phenology annually, the changing process of their leaves’color and the best watching time were recorded. According to the average index of heat resistance, they would be divided into five levels, I grade (1.00to1.50):species with the highest heat resistance, a total of24kinds; II grade (1.51to2.50):species with the higher heat resistance, a total of7kinds; III grade (2.51to3.50):species with average heat resistance, a total of2kinds. According to the average cold resistance index, they would be divided into five grades, I grade (1.00to1.50): species with the highest cold resistance, a total of33kinds. According to the average pest and disease resistance index, they would be divided into five levels, II grade (1.51to2.50):species with the highest pest and disease resistance ability, a total of28kinds; III grade (2.51to3.50):species with average pest and disease resistance ability, a total of5kinds. Taking heat resistance, cold resistance and pest and disease resistance consideration, we can evaluate the ecological adaptability of33kinds of colored-leaf trees. The results show that a total of17kinds of species have a better adaptability and a total of16kinds of species have a good adaptability.3. After a comprehensive evaluation and analysis, which is between ecological adaptability and ornamental value.33kinds of colored-leaf trees are divided into four grades. A tatol of3kinds of species have better ornamental value and ecological adaptability; a tatol of14kinds of species have good ornamental value and a better ecological adaptability; a tatol of1kinds of species has better ornamental value and a good ecological adaptability, a total of11kinds of species have better ornamental value and a better ecological adaptability, a total of4kinds of species have general ornamental value but a good ecological adaptability.4. In the way of subordinate function method, principal component analysis and stepwise regression, the heat resistance of6species of Aceraceae colored-leaf trees have been comprehensively evaluated. According to the value of comprehensive heat resistance, the heat resistances’ descending order is Acer truncatum ’Lihong’, Acer freemanii, Acer negundo, Acer rubrum ’Autumn Fantasy’, Acer saccharinum and Acer platanoides. Combining the comprehensive evaluation values with the heat resistance index, we have established the optimal regression equation M=0.873-0.05A2+0.03A3-0.04A4, and then made a correlation analysis of predictive values obtained by this equation and comprehensive evaluation values. Finally the results show that this equation could accurately predict the colored-leaf trees’heat resistance.