Between November 2013 and May 2014, BIZ carried out a resource survey for baobab in communal and resettled areas of Zimbabwe, to predict the annual harvest of baobab fruit, and how much of a large-scale market could be met sustainably, without creating deficits at the local consumption level or impacting detrimentally on the tree and its environment.
Until recently, only one species of baobab was thought to exist on mainland Africa, Adansonia digitata. However, the presence of a second species, Adansonia kilima, has been confirmed in Tanzania, Kenya, Zambia, Namibia and South Africa. Adansonia kilima is generally restricted to moderate elevations (650-1500m) while A. digitata prefers elevations below 800m.
During the resource assessment, morphological analysis was used to confirm the presence of A. kilima in Zimbabwe also.
Mature trees of A. kilima and A. digitata look similar. There are, however, some differences:
Tree shape: A. kilima is usually bottle shaped, whereas A. digitata is generally broad relative to height.
Flowers: Flowers of A. kilima are smaller (about half the size of A. digitata), and often found in large numbers per tree. Differences in the length and posture of the petals make it easy to distinguish from a distance the smaller, partly closed calyx and partially exposed anthers of A. kilima from the larger calyx with fully exposed anthers and effaced petals of open A. digitata flowers.
Size and density of stomata in leaves: The stomata lengths of A. kilima are much smaller than those of A. digitata. Similarly, the stomatal density of A. digitata is much lower than that of A. kilima.
Leaves were collected from 4 different sample sites around Zimbabwe and the size and density of the stomata were measured. We found that trees could be divided into 2 distinct groups, with the size and density of stomata in each group corresponding with those for A. digitata and A. kilima. This indicates that both species do occur in Zimbabwe and they occur in the same areas.