Big-leaf mahogany  (Swietenia macrophylla)

Classified as Vulnerable (VU) on the IUCN Red List (1), and listed on Appendix II of CITES (3).

The majestic mahogany is a tall tree that towers above the forest canopy. As its name suggests, it bears large leaves, up to 45 centimetres long, which are composed of an even number of leaflets found on either side of the central midrib (2) (4). The bark has a sweet odour and small white flowers are produced, in which the stamens are characteristically fused to form a tube (4). The fruits of the big-leaf mahogany are large, light grey to brown capsules that measure almost 40 centimetres in length. Each fruit contains up to 71 winged seeds, 7 to 12 centimetres long (2).

Big-leaf mahogany has a patchy distribution from southern Mexico through Central America and south to Brazil and Bolivia (5). Information on population numbers is lacking but good stands still persist in Bolivia and Brazil (1).

Found in various forest types (1), the big-leaf mahogany grows at elevations from sea level up to 1,400 metres, in areas with an average annual precipitation of 1,600 to 4,000 millimetres and an average temperature of 23 to 28°C. It prefers rich, deep and well-drained soils (2).

This large tree is extremely long-lived and slow-growing (5). The timing of flowering and fruiting depends on the location of the tree, but in Mexico the small white flowers bloom in April and last until June, and the fruit capsules ripen in January through March the following year (2). When released, the numerous winged seeds are dispersed by the wind (4).

The beautiful hardwood obtained from mahogany trees has been in high demand for centuries. Big-leaf mahogany has now replaced Caribbean (S. mahagoni) and Honduras mahogany (S. humilis) as the most commercially important member of the genus, following the commercial extinction of the latter two species as a result of over-exploitation (5). Big-leaf mahogany is the leading commercial timber of Latin America (6), but many people in the industry are concerned that without enforced protection measures this species may also become commercially extinct within five years (7).

In a vital move for the future protection of this majestic tree, big-leaf mahogany was included on Appendix II of the Convention on International Trade in Endangered Species (CITES) in 2002 (6). Previously, the species was included on Appendix III in many countries but illegal trade continued due to the huge demand and high prices fetched by the wood of this species. It is hoped that this new legislation will enable the sustainable management of this important tree (7).

For further information on the big-leaf mahogany and its conservation see:

• Global Trees Campaign:
  www.globaltrees.org