Conservation of tropical forests through the sustainable production of forest products: The case of mahogany (Swietenia macrophylla King) in the Chimanes Forest, Beni, Bolivia

There is much interest in the role that the sustainable production of forest products can play in tropical forest conservation, by integrating conservation and development objectives, and by providing economic incentives for the retention of natural habitats. Possible forest uses should be evaluated by (i) the sustainability of the extraction activity, and (ii) the impact that extraction has on the residual forest.;In evaluating uses of tropical forests, the logging of mahogany (Swietenia macrophylla) is a natural starting point because of mahogany's long commercial history. In this study, I found that mahogany is a difficult species to harvest sustainably because of its requirement for large disturbances to regenerate. In the Chimanes Forest, Bolivia, mahogany appears to regenerate only after episodic hydrological disturbances of either erosion, or logjam-induced flooding and deposition of alluvial sediments. Since these disturbances are infrequent, most stands have not regenerated for many years, and entire stands can be larger than the diameter limit. With the current lack of management control in the Chimanes Forest, harvest is exceeding sustainable levels. There is little or no regeneration in logged stands, presumably because the disturbances caused by logging are too small.;Because of mahogany's low density, logging to date has resulted in little structural damage to the forest. The Chimanes experience illustrates that silvicultural sustainability is not necessary for low impact forest uses that can achieve some conservation objectives.;The supplies of mahogany are almost exhausted in the Chimanes Forest. Future extraction will depend on lesser known species. We conducted experimental logging at a range of harvest intensities, and found that as harvest intensity increases, per tree structural damage to the residual forest and the regeneration of commercial tree species increases. In the future, having a larger number of commercially viable timber species (and being able to harvest at locally higher harvest intensities) could help achieve silvicultural sustainability. The net impact of having a larger number of commercially viable species will depend on the likelihood of achieving control. With no control, a larger number of harvested species will simply result in equally unsustainable, but more damaging, extraction.