Expediting Reforestation in Tropical Forests Grasslands: Distance and Isolation from Seed Sources in Plantations

background

This study investigates the potential use of tree plantations to facilitate regeneration of indigenous trees in successionally arrested grassland. It focuses on how characteristics of the plantations and native species can determine the type of regeneration occurring in Kibale National Park, Uganda.

Research Goals & Methods

5 plantations were assessed in this study, 4 of which were surrounded by natural forest and 1 which was an isolated plantation. Tree species richness and stem density were assessed in the grassland. Within the plantations, seedling, sapling, and tree regeneration were assessed with respect to distance from plantation edge and various site characteristics.

Conclusions & Takeaways

The results show that plantations differ in species composition and stem density from forest; all plantations had higher tree species richness and stem density than anthropogenic grassland. This suggests that establishment of these plantations facilitated tree species regeneration rapidly increasing richness and stem density than anthropogenic grassland. The relationship between abundance and distance differed among common species. Small seeded animal dispersed species tended to show strong distance effect with decreasing density as distance increased (C. Africana and D. abyssinica), but C. durandii showed a weak decrease in density with increasing distance. C. odorata and M. dura with reproductive adults in plantations showed little or no distance effect. It is unclear why M. dura and A. grandibracteata, both legumes, differed in densities with increasing distance. In addition, the results showed that the isolated plantation had lower species richness and stem density than plantations located adjacent to the natural forests. According to the authors, the results suggest that forest reestablishment will occur faster in regions that have many species with densities that are little affected by distance from plantation edge than in regions that have many species with densities that decrease rapidly with increasing distance from plantation edge.