CLIMATIC BOUNDARIES IN VERTICAL FOREST VEGETATION ZONATION OF SUBTROPICAL EAST CHINESE MOUNTAINS——A CASE OF THE SOUTHWEST MOUNTAINOUS AREAS IN ZHEJIANG

The research of vertical forest vegetation zonation is the frontier issue in global change.In the paper,a detailed analysis is made by using the automatic weather station and meteorological stations data.Based on factor analysis and Mann Whitney U test method,this paper extracts out the main climatic factors and discusses the climatic boundariess problem of vertical vegetation zonation in southwest mountainous areas of Zhejiang province by the comparison between 39 subtropical east Chinese mountains.The results show that the temperature,the climatic seasonality and the wind are the three most important climatic factors.There are significant correlations between winter strength and the boundaries of broad-leaved forests and coniferous forests.The lowest average monthly temperatures between-0.8℃ and-1.2℃,between 2.1℃ and 2.9℃,are the lowest boundaries of deciduous broad-leaf forest and evergreen deciduous broadleaf forest.The annual mean temperature between 13.3℃and 13.6℃ is the boundary between warm-coniferous forest and temperature-coniferous forest.Wind is one of climatic factors on limits of altitudinal forest belts,but we cant qualitativily delimit the climatic boundary now.