Spatial patterns of community-level sprouting in a karst old-growth forest of southwest China

Sprouting is essential for forest regeneration and plays an important role in preserving the stability of the forest community. Few studies have investigated the role of spatial interaction in the sprouting process of natural forests. We investigated the spatial distribution patterns of sprouting trees, the survival of the sprout, the effect of nearby individuals' size on the survival of the sprout, and the ability to sprout of the karst old-growth forests in China's Maolan National Nature Reserve using spatial pattern analysis. Our results show that spatial aggregation patterns of sprouting, dead, and alive trees were detected, indicating dispersal limitation and microsite effect. Sprouting trees were separated from dead trees and attracted to alive trees on a scale of 0 to 2 m, implying that sprouting survival was more likely related to scramble competition and the microsite effect. Mutual stimulation occurred between the diameters of sprouting trees as well as between the diameters of sprouting trees and dead trees, indicating that trees with similar diameters tend to cluster together and that favorable microsite conditions supported sprouting trees to regenerate and grow quickly. Furthermore, the sprouting capacity varied with different diameters and heights of the parent trees, but the sprouting ability did not show a spatial association and was not affected by the size of other individuals nearby at the community level. Taking into account these results, we inferred that microsites might play a very important role in regulating the spatial pattern, survival, and growth of sprouting trees in karst forests.