Rehabilitation of Forest-Savannas in Ghana: The Impacts of Land Use, Shade, and Invasive Species on Tree Recruitment
This study investigates the varying potential of soil seed banks of predominant agricultural land uses for the recruitment of trees from seeds and seedlings in 3 farming communities in a forest-savanna ecological zone in Ghana.
Research Goals & Methods
This research focuses on local ecological knowledge (LEK) of farmers for the natural recruitment of trees from vulnerable newly germinated tree seedlings. It does so by exploring the effects of two factors on tree seedling recruitment: soil seed bank conditions associated with three predominant land uses and sunlight or shading conditions.
Conclusions & Takeaways
The results show an increase in broken forest canopy cover from 1990-2000 by 5,314 hectares. Tree seedlings ranged from 3% of total life forms (in shaded food crop farm soils) to 18% of total life forms (in shaded forest cover soils). The more recruitment-friendly land use fields- forest covered and cacao land uses - were not much different from the more intensively disturbed annual crop fields in terms of the means of germinating seeds. The most common species found in the study area was C. odorata, an invasive shrub that is known to negatively impact tree recruitment. The LEK view on tree recruitment on farms listed the principal environmental factors as the greatest single factor (one response only) that drives germination, establishment and growth of tree species are fire (24%), soil moisture (23%), soil fertility (22%), sunlight/shade (25%). Farmers stressed competition with tree seedlings from C. odorata, stating that seeds will germinate if this invasive is removed by intensive weeding. The authors conclude that for tree rehabilitation in this once densely forested forest-savanna ecological region of Ghana there is the critical need for human - assistance in the realization of the potential for tree recruitment and intensive management of the herb/shrub C. odorata by intensive weeding.
Rehabilitation of forest-savannas in Ghana: The impacts of land use, shade, and invasive species on tree recruitment. Applied Geography. 2011;31:181–190. doi:10.1016/j.apgeog.2010.04.002..
- Luther College, University of Regina, Regina, Saskatchewan, Canada