Swietenia macrophylla
Swietenia macrophylla King, commonly known as big-leaf mahogany, is a large deciduous tree in the family Meliaceae native to the humid tropical forests extending from southern Mexico through Central America to northern South America, including parts of Bolivia, Brazil, Colombia, Ecuador, Peru, and Venezuela.[1][2] It typically reaches heights of 30 to 50 meters with a straight bole up to 2 meters in diameter, large pinnate leaves 50–150 cm long, and small flowers yielding winged seeds dispersed by wind.[3][4] The species exhibits rapid juvenile growth under favorable conditions but slows with maturity, thriving on well-drained soils in lowland rainforests.[1][3] Renowned for its durable, workable reddish-brown heartwood with interlocking grain that resists splitting, S. macrophylla has been a cornerstone of international timber trade since the colonial era, primarily for high-value applications in furniture, cabinetry, interior trim, boatbuilding, and musical instruments due to its acoustic properties and dimensional stability.[3] This economic significance stems from the wood's superior qualities compared to substitutes, driving demand that has historically exceeded sustainable harvest levels across its range.[4][3] Intensive selective logging, often illegal, has caused severe population declines—estimated at over 60% in three generations—prompting its listing as Endangered on the IUCN Red List in 2023 and regulation under CITES Appendix II since 2003 to curb unregulated export and promote verified sustainable sourcing.[5][4] Despite plantation efforts and reforestation initiatives, ongoing threats from habitat loss, pests like the shoot borer Hypsipyla grandella, and weak enforcement in source countries continue to challenge conservation, underscoring the tension between its commercial value and ecological persistence.[5][4]Taxonomy and Etymology
Scientific Classification
Swietenia macrophylla King is classified within the order Sapindales and the family Meliaceae, which comprises tropical and subtropical trees noted for their timber value.[6] The species was formally described by botanist George King in 1886, establishing its binomial nomenclature as Swietenia macrophylla.[7] The complete taxonomic hierarchy, following the classification adopted by the Royal Botanic Gardens, Kew, is as follows:- Kingdom: Plantae[6]
- Phylum: Streptophyta[6]
- Class: Equisetopsida[6]
- Subclass: Magnoliidae[6]
- Order: Sapindales[6]
- Family: Meliaceae[6]
- Genus: Swietenia[6]
- Species: Swietenia macrophylla King[6]
Etymological Origins
The genus name Swietenia commemorates Gerard van Swieten (1700–1772), a Dutch botanist and physician who served as personal physician to Empress Maria Theresa of Austria and contributed to botanical nomenclature through his work on medicinal plants.[10][11] The specific epithet macrophylla originates from Ancient Greek makros (μάκρος), meaning "large" or "long," and phyllon (φύλλον), meaning "leaf," reflecting the species' compound leaves that can reach 50 cm in length with prominent leaflets.[12][13] This binomial nomenclature was formalized by Daniel Oliver in 1867 for the species, building on earlier descriptions by Adolf Engler and others who emphasized the leaf morphology distinguishing it from congeners like Swietenia mahagoni.[14]Botanical Description
Morphological Features
Swietenia macrophylla is a large, semi-evergreen to briefly deciduous tree typically reaching heights of 30–45 m, occasionally up to 50 m, with a straight, cylindrical trunk supported by buttresses and attaining diameters at breast height of up to 2 m.[15] The crown is open, rounded to umbrella-shaped, often irregularly branched in mature specimens.[16] Bark on young trees is smooth and gray, transitioning to thick, plate-like, ridged, and flaky gray to dark brown layers on older trunks, with a rough texture that flakes off in patches.[17][18] Leaves are even-pinnate, alternate, and compound, measuring 16–40 cm in length, composed of 4–8 (typically 8–12) pairs of subopposite or opposite leaflets.[15][19] Leaflets are asymmetric, falcate to elliptic-oblong, 5–10 cm long and 2–5 cm wide, with young foliage emerging pink or red before maturing to dark green; the entire leaf complement is shed seasonally.[18][20] Flowers are small, unisexual (monoecious), and fragrant, approximately 5–10 mm long, with pale green sepals and white tubular corollas featuring toothed edges; they occur in axillary or terminal panicles during late dry seasons.[18] Fruits are erect, woody, ovoid-oblong capsules, 10–15 cm long (up to 22 cm) and 5–8 cm in diameter, grayish-brown, dehiscing longitudinally via 5 valves to release 30–50 seeds per capsule.[21][18] Seeds are flat, reddish-brown, with expansive wings measuring 7.5–10 cm long, facilitating wind dispersal.[21][18]Wood Properties
The heartwood of Swietenia macrophylla ranges from pale to dark reddish-brown, often darkening upon exposure to light, while the sapwood is paler, typically 5-10 cm wide and whitish to yellowish. The wood exhibits interlocked grain, producing distinctive ribbon-like or striped figuring, with a medium to coarse texture due to relatively large vessels.[22][23]| Property | Value |
|---|---|
| Basic specific gravity | 0.52-0.59 (ovendry weight/green volume) |
| Density (at 12% MC) | 530-670 kg/m³ |
| Janka hardness | 800-900 lbf |
| Modulus of rupture | 11,000-13,000 psi (varies by source) |
| Modulus of elasticity | 1,300,000-1,500,000 psi |
| Radial shrinkage | 3.6% |
| Tangential shrinkage | 5.4% |
| Volumetric shrinkage | 9.5% |