Regeneration dynamics of miombo woodland in response to different anthropogenic disturbances: forest characterisation for sustainable management

摘要

Miombo woodland, the most extensive vegetation formation in Africa, recovers well after cessation of disturbances from different land use practices on a site. The core strategy of sustainable miombo woodland management requires a detailed understanding of the implications of land use practices such as charcoal production, slash & burn agriculture and timber harvesting, on miombo woodland dynamics. The study undertook a comparative analysis of the influence of charcoal production, slash & burn agriculture and timber harvesting on woodland recovery at population and stand levels. Sites of known age after abandoning a specific land use were selected where the land uses were practiced in close proximity to each other. This involved characterizing miombo woodland based on some selected dominant species through developing stem diameter class distribution profiles. Most species in charcoal and slash & burn regrowth stands showed gradual development from one size class to another with this development being significantly (P 0.0005) influenced by species rather than the disturbance category. The reason is that the key miombo species are light demanding and require maximum exposure to sunlight to grow fast. By contrast, species in single-tree harvested stands exhibited static stem diameter class profiles with no individuals in certain classes. The study concludes that whilst single-tree selection timber harvesting appears to show that the forest is intact at the stand level, it is actually not a sustainable management option at population level. It also concludes that charcoal production and slash & burn agriculture are necessary disturbances that enhance the establishment and development of the regeneration pool of the miombo woodland species.