Sustaining mahogany: research and silviculture in Mexico's community forests

The most important timber species in Neotropics, mahogany (Swietenia macrophylla) is still harvested from natural forests. The difficulty of ensuring its regeneration in logged-over forests was a primary reason for listing this species in CITES appendix II in 2003, requiring producer countries to develop sustainable production systems. The most advanced efforts are those of communities that harvest multiple products, including more than 8000 m cubic/year of mahogany timber, from all over nearly 730 000 hectares of production forests on Mexico's Yucatan peninsula. Over the past twenty years, their foresters have developed inventories and managment plans and overseen enrichment planting efforts, while researchers have established experiments and studies to evaluate management alternatives. Seven years of research on mahogani regeneration has revealed that mahogany trees with diameters superior to 75 cm are the most important seed producers, but selective harvesting of all trees over the minimum diameter limit of 55 cm is depleting them. Silvicultural experiments on different sizes of clearings have shown that 5 000 square m clearings produced by machinery or burning, treatments which impede resprouting by trees of other species, were most favorable, to establishment and growth of mahogany seedlings. Seedlings did not survive when planted under the forest canopy. Researchers, foresters, government agencies, and communities have been collaborating to integrate these new findings into revised management guidelines and to modify forestry policies accordingly. These findings are likely to be applicable to the management of this species elsewhere in its native range, and possibly also to the closely related African mahoganies