Abstract: Plant community is formed under the combined action of plant and environment. In the formation and development of plant community, landform and climatic factors play important roles. On the basis of plant community investigation, and by using detrended canonical correspondence analysis (DCCA), this paper analyzed the effects of each landform and climatic factor on the plant species number, distribution structure, and diversity in different strata of Pinus yunnanensisforest. The DCCA ordination efficiency for the tree layer, shrub layer, and herb layer was very significant (P<0.01). The effects of environmental factors on the plant species diversity and distribution were in the order of mean precipitation in summer (from May to Sept.), annual temperature range, and mean annual precipitation for tree layer, mean precipitation in summer, mean annual precipitation, and frostfree days for shrub layer, and frost-free days, elevation, and mean precipitation in summer for herb layer. Human disturbances had great effects on shrub layer but little effects on tree and herb layers.

Key words: urea, potassium dihydrogen phosphate, chestnut, photosynthesis characteristics, growth and fruiting.