Enrichment Planting Does Not Improve Tree Restoration when Compared with Natural Regeneration in a Former Pine Plantation in Kibale National Park, Uganda

background

This study assesses the rate of biomass accumulation of planted seedlings relative to natural regeneration in a harvested plantation in Kibale National Park, Uganda. Enrichment planting was carried out in an area where a pine plantation had been harvested to determine the relative value of these management options.

Research Goals & Methods

Two-ha plots were established; in one, 100 seedlings each of 4 native species were planted. To estimate biomass, trees in forestlands that were adjacent to the park were identified; DBH and DGH (diameter at ground level) measured; trees were fell ground level. Trees species commonly found in the regenerating areas were selected so that they were sizes similar to those regenerating in the harvested area.

Conclusions & Takeaways

The results showed that the use of fast growing pine plantations facilitated the establishment and growth of indigenous trees and enrichment planting subsequent to pine plantation harvesting was not necessary to a obtain rich tree community with a large number of new recruits. This was attributed to a number of factors such as species ability to resprout following injuries from harvesting. Also at the end of the study many of the existing trees with DBH between 5 and 30cm species appeared to be the result of resprouting from broken shoots or injured stems. The authors conclude that even though performance in enrichment planting has high probability of success especially when planting is timed to optimize survival; enrichment planting involves high costs in nursery maintenance and field labor. Given the positive rates of restoration both in terms of species richness and biomass accumulation. It is important to evaluate whether natural regeneration will meet management needs before suggesting enrichment planting.