Impact of land-use type and bark- and leaf-harvesting on population structure and fruit production of the baobab tree (Adansonia digitata L.) in a semi-arid savanna, West Africa.

摘要

Non-timber forest products (NTFPs) strongly contribute to livelihood security in the semi-arid tropics. There is increasing concern about the population status of NTFP-providing trees and therefore a need for their sustainable use. Thus, this study examines the impact of land-use type on the multipurpose baobab tree (Adansonia digitata L.) in Burkina Faso, combined with rates and patterns of bark- and leaf-harvesting, and their impact on fruit production. We compared stands in a protected area (W National Park of Burkina Faso) with those of surrounding communal area (fallows, croplands and villages) to obtain an indication on the status of the baobab population, to assess its harvesting tolerance and to estimate to what extent their actual use is sustainable. Our results reveal that land-use type has an impact on the population structure of the baobab. The size class distribution curve of park stands was inverse J-shape which indicates good rejuvenation, while the curve of fallows, croplands and villages stands was bell-shaped, indicating a lack of recruitment. However, a high number of seedlings were recorded in villages. Nearly all baobabs were pruned and debarked in villages, croplands and fallows while half of the individuals were harvested in the park. Most of the trees were pruned and debarked moderately. Debarking and pruning were slightly size specific. Pruning in interaction with tree-size had a significant impact on fruit production. In contrast, debarking had no effect on fruit production. We conclude that despite the land-use impact and the intense harvesting, baobabs are still well preserved in the communal area due to their longevity, extremely low adult mortality rates and traditional management practices. However, land-use intensifications may lead to increasing pressure on baobab populations in the future. Therefore, adapted management strategies are needed to guarantee the persistence of this important species and to avoid a shortage of baobab products.Digital Object Identifier http://dx.doi.org/10.1016/j.foreco.2010.09.009