Shade tolerance and regeneration of some tree species of a tropical rain forest in Western Kenya

Abstract

Shadetolerance and regeneration of some heavily exploited timber species(Uvariopsis congensis, Antiaris toxicaria, Funtumia africana,Prunus africana and Aningeria altissima)were studied in two adjacent sites in Kakamega tropical rain forest. The twosites have been subjected to different logging intensities. Within one of thesites, relatively intact areas were compared with adjoining more disturbedones.Seedling presence or absence in mature forest phase, sapling proportions in gapand the mature phase and diameter distributions were used to classify thespecies into shade tolerance groups. Results indicate that except forUvariopsis, the species are non-pioneer lightdemanders and could fit into three shade tolerance groups: A groupresembling pioneers but with seedling in shade, a mid-tolerant group andone showing a high shade tolerance. Amount of regeneration and disturbance wererelated: regeneration being higher in the more disturbed site except forUvariopsis. The intersite differences were mirrored whendisturbed and adjoining more intact areas within one of the sites werecompared.Species more abundant in the disturbed site also generally scored low in shadetolerance. However, the mid-tolerant Funtumia andnot Prunus or Aningeria that hadlowershade tolerance scores, dominated regeneration in the disturbed forest parts.The shade tolerance data suggest that Uvariopsis, Funtumiaand Antiaris could be amenable to natural forestmanagement. For Prunus and Aningeria,artificial regeneration in buffer plantations around the natural forest may beabetter option.