point of carbon dioxide; E -transpiration rate; FE -forest edge; FG -forest gap; gs -stomatal conductance; H -high altitude; L -low altitude; LA -leaf area; LCP -light compensation point; LL -leaf length; LM -leaf mass; LSP -light saturation point; LW -leaf width; M -middle altitude; MT -mature individuals of T. sinense; PN -net photosynthetic rate; PNmax -the maximum net photosynthetic rate of the PN-PAR; P * Nmax -the maximum net photosynthetic rate of the PN-CO2; RD -dark respiration rate; Rp -light respiration rate; SLA -specific leaf area; US -understory; YT -young individuals of T. sinense. Acknowledgements: We thank all staff in Meigu Dafengding National Nature Reserve who help to collect data, and thank Xueheng