资源环境科技发展态势分析平台

This study investigates the short-term influences of canopy gap size on the growth and spatial patterns of Chinese pine (Pinus tabulaeformis) regeneration established before (REBG) and after (REAG) gap creation. We established four gap sizes based on the mean height (H) of the canopy trees, comprising minor (0.75 H), small (1.00 H), medium (1.25 H), and large (1.50 H) gaps, and three closed canopy reference plots (10 x 10 m) in a, plantation in northern China. Seven years after gap creation, each gap was divided into three sections according to the mean crown radius of the border trees, including the gap central area (section B), the sun-exposed gap edge (section C) and the less sun-exposed gap edge (section D). A quantitative analysis revealed no difference in the density of REBG and REAG among the different gap sizes or sections; however, their heights significantly increased with increasing gap size. Significantly taller and shorter regeneration were generally found in section B and under the closed canopy, respectively, whereas those in sections C and D showed no notable differences in height. The spatial patterns of REAG and REBG were mostly random and there were no spatial associations between these two age classes of regeneration within individual gaps. Among gaps of different sizes, the maximum density of REAG occurred most often along the northeastern edges of gaps with a diameter of less than 1.5 H, whereas the highest density of REBG appeared in the center and along the southeastern edges of minor gaps and the northeastern edges of large gaps. The spatial patterns in height of the regeneration were similar to those of abundance. Our exploratory analysis revealed that gap expansion along the northeastern edge will likely be necessary to encourage canopy gap closure and successful recruitment in the study area. Further continued monitoring might be required to determine the long-term efficacy of gap creation and such expansion. (C) 2016 Elsevier B.V. All rights reserved.