Grain Size Effect on Landscape Pattern Indices——A Case Study of Shenyang Urban Forest

Grain size effect on landscape pattern indices of Shenyang urban forest was investigated at the fine-grain scale(one side of a pixel was less than 30 m) through 25 commonly used landscape indices based on the QuickBird satellite image taken in 2006.The results showed that(1) the 25 landscape pattern indices can be divided into three types according to their responses to grain size changing.Indices of the first type increased or decreased monotonically,and the second type showed u or n style,while the third group displayed uncertain responses;(2) Responses of landscape pattern indices to grain size changing of the five urban forest types fell into two trends.Patch number of subordinated forest and road forest decreased fast with grain size changing,which caused the corresponding landscape pattern indices to change greatly,because the two urban forest types were mainly composed of small patches.On the contrary landscape and recreation forest,production and management forest,and ecological and public welfare forest,characterized by big patches,were not sensitive to patch number but sensitive to patch area,which made landscape pattern indices such as area weighted mean patch size and effective mesh size to change greatly;(3) 5 m was the optimal grain size for Shenyang urban forest landscape pattern research based on landscape pattern indices scalogram.