Ecological stoichiometry within plant organs of four forest trees in Sygera National Forest

Four typical forest types in Sygera Mountain, namely, Pinus armandii (PA), Picea likiangensis var. linzhiensis (PLL), Abies georgei var. smithii (AGS), and Juniperus saltuaria (JS) were considered using methods such as analysis of variance and stoichiometry. Effects of changes of nutrient content and stoichiometric ratio of various organs of arbor plants were evaluated. Compared with global plant nutrients, this study area had lower N and P contents. The growth of the Juniperus saltuaria forest was jointly restricted by N and P, and as the environmental gradient decreased, the growth of the other three forest types changed from N and P joint restrictions to N restrictions. The distribution order of element content in various organs among different forest types was consistent as follows: leaf>branch>root>trunk. There was a strong domestication reaction between N and P contents. This led to a significantly higher C/N ratio of the square branch Berlin compared to the other three forest types, while the C/P and N/P ratios were opposite. This may be due to the “optimal allocation principle” of nutrients in various organs under different environmental conditions. The nutrient allocation patterns of plant organs in different forest types were not the same, which reflects the differences in life strategies and nutrient utilization among different forest species.