A 140km “Urban suburban rural” gradient in New York City was set up and used to study the effects on urbanization on forest vegetation,forest soils and forest landscape.Along the gradient from urban to rural area,the types,composition and community structure of forest vegetation very obviously.The contents of main heavy metals in forest soils go down gradually.The number of forest patches decreases,their size increases,the heterogeneity of landscape decreases.These variations are closely related to traffi...