Influence of neighbor competition and tree attributes on the fruit production of Sinomanglietia glauca, an endangered tree species endemic to China

Abstract

Sinomanglietia glauca is a critically endangered species with limited population and narrow distribution in China. Yet to date, we know surprisingly little about how the characteristics of forests affect the reproduction process of S. glauca individuals. The fruit production of S. glauca individuals was examined in artificial forest (AF), free-encroached deciduous forest (FF), and intensively encroached forest by evergreen trees and moso bamboos (EF) at Mingyueshan Mountain in Jiangxi province. The relationships between the characteristics of fruits and seeds and those of parent trees and neighborhood were analyzed through redundancy analysis. The fruiting indicators (number, weight and volume of fruits/seeds) for S. glauca in AF were significantly higher than those in EF and FF. The fruit production was positively related to the crown radius and the ratio of crown length to tree height, and was negatively linked to neighbor enclosure index. The characteristics of parent trees, neighborhood and their interaction explained the variation of fruit production by 70.6%. Although the competition of neighbors exerted less explanatory power than the characteristics of parent trees, it was negatively correlated with the crown radius and volume. The crown radius and neighbor enclosure were identified as the two dominant causal factors taking the major responsibility to the fruit production. The increasing competition from neighbors bring detrimental impacts on the fruiting of S. glauca. Efficient management strategies were proposed to reduce the interference from neighbors, such as reasonably pruning and thinning adjacent evergreen trees and bamboos.