Abstract: Pinus yunnanensis, an endemic conifer species in southwestern China, is important for regional economic development and soil and water conservation. Here, we investigated the elevational variations of diameter at breast height (DBH), tree height, leaf morphology and carbon (C), nitrogen (N) and phosphorus (P) concentrations of mature individuals of P. yunnanensis in natural secondary forests of northeast Yunnan. We analyzed adaptive responses of foliar C∶N∶P stoichiometry along the elevation gradient. The results showed that DBH, tree height, leaf P concentration and C∶N ratio increased first and then decreased with elevation, while C∶P and N∶P ratios exhibited an opposite pattern. In addition, leaf length per bundle, specific leaf length, and concentrations of C and N were lower at higher elevation, while dry mass per bundle increased with elevation. Leaf N∶P (mean 5.82±0.10) in each elevation was lower than 14, which was significantly negatively correlated with DBH and tree height. These results suggest that P. yunnanensis showed adaptive growth and leaf nutrient balance with elevation. The growth of P. yunnanensis was limited by N, supporting the growth rate hypothesis where growth rate is expected to be negatively related with plant N∶P. The elevational patterns of stoichiometric characteristics of P. yunnanensis revealed in this study could be helpful for vegetation management.

Key words: ANPP, forest aboveground biomass, LANDIS-Ⅱ model., RCPs