INFLUENCE OF BIOPHYSICAL FACTORS VARIATION ON TREE SPECIES STRUCTURE AND COMPOSITION

Abstract

Forests are important for survival and development of human and other fauna. However, they are under degradation due to changes in biophysical factors affecting tree species structure and composition. Understanding these variations and its influence on tree species structure and composition guides conservation of forest. This study aimed at assessing the influence of biophysical factors variation on tree species structure and composition. Ecological study survey was used, tree species and soil samples were studies from 12 sample plots. Tree species were enumerated and recorded by species name and DBH, those with ≥3m height and DBH > 5 cm were classified as trees, while those with ≤3m height and less than DBH ≤5cm were recorded as saplings. Tree species attributes assessed included: tree DBH and diversity, while biophysical variables measured were: soil organic carbon, soil texture, phosphorous and Potassium. A total of 129 species were identified with majority being saplings. ANOVA for biophysical factors indicated significant variation in forest edge-interior gradient, the correlation analyses of species and biophysical factors showed SOC, P, clay and silt showed a positive correlation for most of the species. The CCA results indicated positive correlation between tree species diversity with variation in biophysical factors, the presence of gaps with high P levels were associated with majority of the saplings, however, the DBH class distribution did not observed an inverse J-shape portraying high degradation. The tree species-biophysical factors should therefore be utilized with other environmental factors such as topography when planning and choosing species for rehabilitation and restoration programmes.