Sharp loss of mahogany in South America, study finds

Image credit, CITES.Scientists estimate that 66% of the historic range of mahogany in South America has been lost to commercial logging and forest conversion. Furthermore, the remaining stock is extremely low density and located in remote areas indicating that the best commercial stands have been thoroughly logged. 

Big-leaf mahogany (Swietenia macrophylla) is an extremely high-value timber species. Consumer demand for the wood in a variety of products has fueled intense exploitation pressure. It was listed included in Appendix II of the Convention on International Trade in Endangered Species (CITES) in 2002.

James Gorgan from Yale University and fellow researchers used a combination of satellite imagery and a survey of experts to estimate the historic range of big-leaf mahogany and determine the extent of current loss.

Their rapid, qualitative approach, while somewhat rough, has allowed them to arrive at figures that otherwise would be extremely time consuming and expensive using a more precise, quantitative methodology. For example, they note that their study cost $93,000 compared to $538,000 spent on a field-based inventory just for mahogany in Peru.

A similar qualitative approach could be used to for other threatened tropical trees such as Cedrela spp. and Dalbergia spp. The data gathered can prove valuable in conservation efforts - particularly in developing stronger regulations on international trade under CITES. The authors write,

Empirical information on the geographic range and commercial status of high-value timber species in the neotropics is rare and fragmentary. This lack of information can cripple international public policy debates considering regulatory responses to unsustainable
harvests.

In the case of Mahogany, the losses have been great but there appears to be some hope. The  study estimates  a historic range of 278 million hectares and of this, 58 million hectares have been lost to deforestation and an additional 125 million hectares have been logged.

But countries such as Brazil and Bolivia have taken substantial steps to curb the losses and institute more sustainable practices.  For example, both countries have instituted strict regulations on mahogany harvesting.  However, more needs to be done on the part of both producing and consuming nations - this study provides much need data in supporting these efforts.

--Reviewed by Rob Goldstein

Grogan, J., Blundell, A., Landis, R., Youatt, A., Gullison, R., Martinez, M., Kómetter, R., Lentini, M., & Rice, R. (2009). Over-harvesting driven by consumer demand leads to population decline: big-leaf mahogany in South America Conservation Letters DOI: 10.1111/j.1755-263X.2009.00082.x