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Postlogging structural changes and regeneration of Olea welwitschii (Knobl) Gilg. & Schellemb. in the Kibale National Park, Uganda


  • The author declares no conflicts of interest



The study was conducted in the Kibale National Park forest where both light and heavy logging was conducted during 1969–1970. The forest areas which had high stocking densities of Olea suffered the heaviest logging impacts. Research on the autecology of Olea welwitschii (Knobl) Gilg. & Schellemb., an excellent timber species, was undertaken to examine the effects of differential logging intensities on its residual population structure, tree morphology and regeneration. A series of quadrats were placed in the lightly and heavily logged forests, unlogged mature forest and in ecotonal forest tracts. All Olea trees, irrespective of size within the plots, were identified, marked, mapped and their diameter at breast height, height, branching height and multiple stemming measured. Results indicate that the distribution and abundance of Olea tree species was influenced by variations in human disturbances. Heavy forest disturbances created conditions similar to those in ecotonal sites which encouraged successful Olea tree colonization, regeneration and fast growth. However, the closed and semi-closed canopy conditions following logging suppressed Olea regeneration. These observations qualify Olea to be a colonizer and light demander in the juvenile seral stages. It exhibits high tree mortality across all size classes and low survival under natural forest conditions compared with other typical forest climax species. Heavy logging also led to shorter multiple stemmed Olea trees which retained multiple branches on the trunks below the main canopy. Consequently, low-level timber harvesting seems compatible with sustainable Olea utilization. The characteristics of Olea as a colonizing as well as canopy tree species makes it ideal for domestication, forest restoration and plantation management.