Baobab (Adansonia digitata L.) population structure across different agro-ecological zones in Coastal and lower Eastern Kenya

ABSTRACT Baobab (Adansonia digitata L.) is a multipurpose wild fruit tree of sub-Saharan Africa with unknown population demographic stability. This study assessed the baobab population structure in two main growing regions of Kenya where thirty-five plots (0.5 × 3 km each) were set in two transects, along road C107 in the coastal region and B9 in the lower Eastern Kenya, covering different agro-ecological zones (AEZs). For all baobabs within a plot, position, height and diameter at breast height (DBH) were recorded, stem densities calculated and DBH size-class distribution (SCD) curves developed. In total, 599 and 1351 baobab trees were recorded in the 14 and 21 plots in the Coastal and lower Eastern regions, respectively with densities of 0.285 (±0.07 S.E.) and 0.429 (±0.07 S.E.) stems/ha, respectively. The rather dry AEZ “Lower Midland 5” had a significantly higher density of mature (p = .047) and total trees (p = .028) than the other zones. However, at regional level (coast versus eastern), there were no significant differences in the densities of juvenile, mature or total baobab trees. Negative SCD slopes obtained in the two regions indicated more trees in the smaller size classes and hence good recruitment. The results indicated stable populations in general, but local communities should be encouraged to maintain existing trees and promote the establishment of young baobabs.