Stand Diameter Size Diversity in Pinus kesiya var. langbianensis Natural Forests

Purpose This study discussed the stand diameter size diversity of Simao pine(Pinus kesiya var. langbianensis),and the correlation and change trend between stand diameter size diversity and environment had been analyzed.Method Forty-five plots of Simao pine natural forests had been investigated in Pu'er City of Yunnan Province, China. And Shannon index (H), Simpson index (D) and Gini coefficient (G) for overall stand, Simao pine and other trees in plots were selected to quantify the stand diameter size diversity. Then,the variations of stand diameter size diversity had been analyzed respectively along with climate factors, topographical factors, soil factors, stand factors, and the comprehensive change trend of stand diameter size diversity along with environmental factors had been analyzed by detrended correspondence analysis (DCA).Results (1) The variation of stand diameter size diversity indices of other trees were larger than overall stand and Simao pine, while the indices of overall stand and Simao pine were consistently. The stand diameter size diversity performed as all trees ≥ Simao pine > other trees in the plots. (2) H_t,H_s,D_t and D_s had the consistent change trend along with climate factors, topography factors, soil factors and stand factors, H_o and D_o also had the consistent change trend while the change of Gini indices were irregularity. (3) H_t,H_s,H_o,D_t,D_s and D_o had significant related with DCA first axis, and the indices had increased along with the first axis. All climate factors were not relation significantly with DCA first axis, and altitude of topographical factors, total potassium (TK), hydrolysable nitrogen(HN) and available potassium(SK) of soil factors, and stand dominant height and average height of stand factors had significant correlation with DCA first axis, and the correlation coefficients were greater than 0.5.Conclusion The diameter size diversity of Simao pine stands was effected by topography, soil and stand factors.