Abstract: Exploring ecological stoichiometry of carbon (C), nitrogen (N) and phosphorus (P) in tree layer of forest is of great importance to understanding nutrient allocation and limitation status in the dominant layer of forest community. Different organs (leaf, branch, trunk, bark, and root) of five typical forests (Pinus yunnanensis forest, Pinus armandii forest, evergreen broadleaf forest,Quercus semicarpifolia forest,Keteleeria evelyniana forest) were sampled in subalpine area of central Yunnan. The concentrations of C, N and P were measured and C∶N∶P stoichiometry were analyzed. The results showed that the ranges of C concentrations in the leaves, branches, trunks, barks and roots of five forest types were 482.40-576.03, 472.50-566.47, 462.67-512.30, 465.10-542.30, 478.67-566.47 mg·g^-1, N concentrations 11.30-25.42, 4.20-7.47, 3.49-8.30, 6.18-9.71, 6.08-10.64 mg·g^-1, and P concentrations 0.84-2.36, 0.42-1.02, 0.25-0.81, 0.30-0.82, 0.55-1.63 mg·g^-1, respectively. The difference of C concentrations was not different among organs. The concentrations of N and P in leaf and root were higher than other organs. The C concentration, C/N, and C/P in the evergreen broad-leaved forest and Q. aquifolioides forest were ranked as: trunks > roots > leaves > branches > barks, the N concentration presented in the order of leaves > roots > barks > branches>trunks, while the C/P of the other three forest types were ranked as: trunks > barks > branches > roots > leaves. The P concentration in the organs of the five forest types followed the order of leaves>roots>branches>barks>trunks. The N/P in the four types of forests were between 10 and 20, and that in the evergreen broad-leaved forest was less than 10, indicating that the growth of the evergreen broadleaved forest was mainly limited by N and the other forest types were colimited by N and P. The results of twoway ANOVAs showed that the C concentration and N/P varied among forest types, while the N and P concentrations, C/N and C/P varied among organs.

Key words: information visualization, applied ecology, research hotspots, bibliometrics, evolution