Simulating Diameter Structure:A Comparison of Nonparametric Kernel Method,Histogram Method and Diameter List Method Spatial pattern gradient analysis of a transect in a hilly urban area in China from the perspective of transportation corridor sprawl Evaluation and simulation of historical range of variability of forest landscape pattern in Huzhong area STUDIES ON KERNEL DENSITY ESTIMATION OF SPECIES ABUNDANCE DISTRIBUTION IN TWO COMMUNITIES OF RARE AND ENDANGERED PLANTS