Spatial patterns of leaf carbon, nitrogen, and phosphorus stoichiometry and nutrient resorption in Chinese fir across subtropical China

Understanding patterns and drivers of leaf carbon (C), nitrogen (N), phosphorus (P) stoichiometry and nutrient resorption at large geographical scales is important to understand the plant adaptation strategy under climate changes. However, most current knowledge was obtained from multi-species based on field investigation and literature data. Whether it is equally applicable to individual species needs further exploration. Here, we determined C, N, and P concentrations of mature leaf and leaf litter, and calculated the nutrient resoprtion efficiency (NuRE) from 19 Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) plantations across subtropical China with relatively wide ranges of latitude and altitude. Results showed that leaf C concentration was high, while leaf N and P concentrations were low, leading to high C:N and C:P ratios in leaf. The CRE was relatively low, and PRE was significantly higher than NRE. Leaf C concentration and CRE increased with latitude, mainly driven by mean annual temperature (MAT). Leaf P concentration and PRE increased, and C:P and N:P ratios decreased with altitude, mainly driven by soil P concentration. In middle-aged group, stand age significantly affected the leaf N and P concentrations, and the C:N and C:P ratios. CRE and PRE were influenced by leaf C and P concentration, respectively. These results indicated that leaf C, N and P stoichiometry and nutrient resorption displayed different spatial patterns in subtropical China, which were mainly induced by the variations of heats and soil P status. Additionally, our findings suggested that forest development affected the leaf stoichiometry but not the nutrient resorption in the middle-aged group. Overall, this study is expected to reveal the nutrient trade-off mechanism of Chinese fir in response to future climate change, and to provide reference for basic stoichiometric parameters of individual species for the establishment schemes in the carbon and nutrient cycling model for large-scale plantation.

Automated summary

Understanding leaf carbon, nitrogen, and phosphorus stoichiometry at large geographical scales can help reveal plant adaptation strategies to climate change. Research in subtropical China showed different spatial patterns of leaf nutrient concentrations and resorption efficiency, driven mainly by temperature and soil phosphorus levels, while forest development impacted leaf stoichiometry but not nutrient resorption in mid-aged stands.