The Role of Selected Environmental Factors on the Regeneration of (Ocotea usambarensis ) in Mount Kenya Forest, Kenya

Abstract

Despites the propagation efforts, density of Ocotea usambarensis has continued to diminish in the southern slopes of Mount Kenya. The species which is native in the montane forest is seldom on farm and found as remnant species. The concerns on the role of environmental factors and how they influence regeneration of Ocotea usambarensis have been sidelined resulting to lack of adequate information that would be required for modeling how to reestablish Ocotea usambarensis. This study therefore examined the role of Rainfall, Humidity, Temperature, wind speed and soil characteristics on regeneration of Ocotea usambarensis. The study was conducted in the southern slopes of Mount Kenya forest. Data on environmental factors, regeneration status and species diversity were analyzed using regression, Pearson Correlation, Shannon- Wiener (H ) Index and Simpson (D) Index. The regeneration status was “J” shaped with mature trees more than regenerants. The relationship was strong (R2 = 78%) between humidity and rainfall (P < 0.05) while for temperature and wind speed were insignificant. The correlation between soil compositions varied significantly (P< 0.05). The soil pH positively correlated with soil nutrients while Cation exchanges capacity negatively correlated with potassium and silicon. It was observed that Diospyros abyssinica was growing in close association with O. usambarensis playing the role of nurse species. With the absence of seedlings in most of the sites and the limiting environmental factors, promotion of vegetative propagation and enrichment planting would enhance conservation and restoration of the species in Mt. Kenya forest. The high levels of soil nutrients and Cation exchange capacity in forest soils indicated the need to maintain them high on farm for optimal growth rate. Enhancing optimal environmental conditions for growth would enhance conservation and restoration of the Ocotea usambarensis