Sprouting as a survival strategy for non-coniferous trees: Relation to population structure and spatial pattern of Emmenopterys henryi (Rubiales)

Abstract

To improve the management and protection strategies of Emmenopterys henryi, the effect of sprouting on the population and spatial distribution pattern was explored. Environmental conditions of the community, tree diameter at breast height (DBH), and height of each individual tree were obtained using a contiguous grid quadrate method in four plots of deciduous and evergreen broad-leaved forests in Dapan Mountain National Nature Research in Zhejiang, China with the largest distribution area of E. henryi. The principal components analysis (PCA) showed that the sprouting ability of E. henryi is strongly related to the degrees of rock bareness, altitude, and slope. The analysis of the population structures showed that the population of group A only with parental trees was in decline due to a lack of seedlings and saplings, whereas the population of group B with both parental trees and sprouts (group B) was increasing. Groups A and B differed in their spatial distribution patterns in the plot 2, with group A showing a random distribution and group B displaying an aggregated distribution. Because the optimum block scale was between 16 m2 and 32 m2, analyses of the spatial pattern and dynamics of the spatial pattern at 25 m2 could accurately reflect the true distribution. The population of E. henryi is small, and the spatial patterns of the population indicated an aggregated distribution with the exception of plot 2 of group A. Plot 2 showed significant environmental deterioration from nearby rocks and ravines, and as a result, a number of small trees died from root exposure, which led to a random distribution of plot 2. The effects of sprouting should be considered when studying the population and spatial patterns of plants.