Assessment of the floristic and structural outcomes of forest restoration in Mpanga Forest Landscape, Mpigi District

Abstract

Tropical forest restoration is a critical global strategy for mitigating biodiversity loss and climate change. However, the effectiveness of active restoration in replicating the ecological complexity of natural forests remains a subject of intense debate. This study examined the floristic (composition and diversity) and structural outcomes of restoration in Mpanga forest landscapes, Mpigi district. A total of 16 concentric circular plots (six in the restored forest and 10 in the natural reference forest). Seedlings, saplings and trees were recorded in the plots to assess species composition, diversity and structure. The results revealed the species composition was distinct, with the restored forest dominated by early-successional species like Bosqueia phoberos, while late-successional species such as Khaya anthotheca were largely confined to the natural forest. Species richness, evenness, and Shannon-Wiener diversity were higher in the natural forest, while species abundance was significantly higher in the restored than natural forest. Structurally, the restored forest had a similar stem density but a significantly lower basal area. Its diameter distribution was bell-shaped and skewed towards small trees (0-9.9 cm), indicating an even-aged stand. In contrast, the natural forest exhibited a stable, inverse-J distribution with trees across all size classes. These findings demonstrate that while restoration can establish tree cover, it has not yet replicated the complex floristic and structural outcomes of a natural forest, highlighting the need for long-term management and strategic interventions.