Forest structure characteristics in disturbed and undisturbed sites of Mt. Elgon Moist Lower Montane Forest, western Kenya

Abstract

This paper, reports results of an ecological study carried out in Mt. Elgon moist lower montane forest, Kenya. The vertical and horizontal structure of the forest was investigated in a bid to better understand the ecological state and management needs of the forest. The assessed forest attributes were (1) stocking levels, (2) diameter size distribution structure for all tree species combined and for five dominant tree species individually, (3) vertical stratification—vegetation layers identification and differentiation, canopy continuity and foliage dispersion. Forest sampling was done in both heavily and lightly logged-over sites. From the results, Mt. Elgon moist lower montane forest can be classified as an under-stocked tropical mixed rain forest. Tree densities varied among sites either as a result of logging, site quality or both. Diameter size for all species combined followed the reverse J-curve, typical of uneven-aged mixed forests. Regeneration and recruitment patterns of the forest and of individual tree species varied among sites; and in spite of a good overall forest regeneration, this did not necessarily mirror the regeneration status of constituent tree species. Both vertical and horizontal forest structure characteristics seem to suggest a building phase for the forest. Data reveal a forest canopy characterized by dispersed foliage intersected by forest gaps (±200 m 2) leading to thick and continuous undergrowth. Elevation, logging intensity and forest development history seem to be the main factors attributable to the observed structure and regeneration of Mt. Elgon forest.