Twig and leaf traits of Michelia wilsonii at different developmental stages in Zhougong Mountain, Ya’an

Abstract

Objective This study, with an examination of the twig and leaf traits of Michelia wilsonii at different developmental stages, is aimed to research the balanced utilization of such resources so as to better predict the spatial distribution of the branch and leaf traits. Method With the M. wilsonii of Zhougong Mountain in Ya’an selected as the research object, the standardized major axis regression (SMA), principal component analysis (PCA) and geostatistical methods were employed to study the correlation and spatial characteristics of twig and leaf traits at different developmental stages. Result (1) The fresh leaf weight, dry leaf weight, dry matter content, leaf area, specific leaf area, leaf thickness, annual twig density, biennial twig density and biennial twig dry matter content were significantly different among developmental stages (P＜0.05), while the annual twig dry matter content was not significantly different among developmental stages (P＞0.05); (2) There was a significant correlation between leaf traits among developmental stages (P＜0.05) and a significant correlation between twig traits (P＜0.05) while the correlation among leaf and twig traits was weak(P＞0.05); (3) The optimal model of the semi-variogram function was linear model for the twig and leaf traits among the whole population, with a distribution of randomness while the big tree stage, with a distribution of aggregation, mainly followed the exponential and spherical model; the spatial correlation of small and medium tree stage is weak. Conclusion As developmental stages advance, the yielding of profits by M. wilsonii slows down and the distribution of twig and the employment of the semivariance function can help predict leaf traits. [Ch, 2 fig.7 tab. 30 ref.]