Impact of enrichment planting on tree species diversity in Kibale national park

Abstract

Historically, most of the Kibale NP was either massively logged or selectively harvested reducing tree species densities. However, the gazettement of area into national park and ceased large scale tree harvest from the forest. As well tree planting through enrichment strategies to restore the tree species richness has been implemented in the degraded areas. Thus, the unique history provides an excellent opportunity to understand the extent of forest restoration and suggest strategies for further restoration. The study investigated the variation of tree species diversity in enriched and natural regenerating habitats of Kibale National Park (KNP). A total of 20 quadrates of 20m x 20m established in each site were sampled measuring all live tree with DBH ≥10 cm. Overall, 552 tree species from enriched site and 457 from the naturally regenerating sites were enumerated. The three most dominant families in the two sites were Apocynaceae (44.5%,), Fabaceae (14.6%) and Canellaceae (8.3%) and Apocynaceae (22.4%), Cannabaceae (18.5%) and Ebenaceae (16.7%) in the naturally regenerating site. Tree species richness using the Shannon-Wiener diversity indices was 2.0598 for the enriched site and 2.1726 for the regenerating site. The calculated species evenness index was 0.6765 for the enriched site and 0.6765 for the naturally regenerating site. The most dominant tree species was Funtumia elastica with an IVI value of 165.18 in enriched and 48.7 for the natural regeneration. The diameter class distribution structure of the trees for both sites depicted a reverse J-shaped pattern indicating a relatively young forest. The Sorensen value was 0.37 indicating that 37% low degree of similarity between the two sites. Thus, the study indicates the potential of enrichment planting in restoration of degraded natural areas.