Consequences of plantation harvest during tropical forest restoration in Uganda

Background

Timber plantations have recently received considerable attention as a forest restoration strategy for heavily degraded lands in the humid tropics. Plantations can facilitate secondary forest regrowth by providing an understory environment more favorable for native plant recruitment than unmanaged degraded habitats. This study explores how using plantations as a restoration tool affects forest succession; how initial floristics affect successional pathways; and the effect of fire exclusion or other interventions.

Research & methods

The study was conducted in Kibale National Park, Uganda. The land was previously used agriculturally with plantations of pine (high density) and cypress (low density) established in the 1950s. Long-term plots were established shortly after logging in both forest types, as well as in unlogged plantations, and were surveyed every two years for stem diversity and abundance, with subplots surveyed for stems < 1 m.

Conclusions & takeaways

In unlogged sites, tree seedling density, species richness, and sapling height were much greater in high-density than low-density plantations. After logging, density, richness, and height were similar across plantation types. Twice as many seedlings and species were found in sites with moderate disturbance from timber activity than in sites with high disturbance. One fire-excluded site was included in the study. The fire-excluded site had greater tree sapling density, species richness, and height than unlogged plantations and greater tree sapling density and species richness than plantation 6 years after logging.

The study suggests that fire exclusion as a strategy for promoting forest succession should be considered alongside forest plantations.