Swietenia humilis aka Pacific Coast Mahogany

Swietenia humilis belongs to the mahogany family, Meliaceae. People call it Mexican mahogany or Pacific Coast mahogany. Its native range runs from Mexico south to Costa Rica. It grows in the tropics, where a clear dry season occurs. Useful Tropical Plants cites the 2010 IUCN Red List. That list gives the tree a Vulnerable status.

Trees reach about 49–66 feet [15–20 metres] in height. The short trunk often bends and has no buttresses at its base. Its width ranges from about 1–1.6 feet [0.3–0.5 metres]. This deciduous tree sheds its leaves rather than keeping them year-round. The trunk and branches give off a clear gum. Bees carry pollen between its flowers. The tree can cross with two other species. These are Swietenia macrophylla and Swietenia mahagoni.

Wild trees grow in dry forests, grasslands, scrub, and rocky sites. They also grow in farm fields and pastures. Farmers keep single trees spread across this worked land. In Guatemala, the tree grows in moist forests too. It also grows there in forests that are quite dry. Across its range, it reaches about 3,937 feet [1,200 metres] above sea level. People grow it for its looks and as roadside hedges. They also plant it near homes. Trees planted along valleys can help limit soil loss.

Growers raise this tree from seed. They sometimes sow seeds where the trees will stand. Fresh seed needs no treatment before growers sow it. Stored seed may sprout better after twelve hours in warm water. In nurseries, growers sow in light sand, under shade, or in containers. Seeds take about ten to twenty-one days to sprout. Growers then remove shade and harden the young trees before planting out. Dried seeds can keep for several months at room temperature.

Local carpenters use the heavy wood, though its role in trade is small. People have used seed oil in cosmetics and soap. Plant extracts have cut feeding and growth in mealworm larvae. There are no known food uses. The bark and seeds hold an alkaloid reported to be very poisonous. Folk medicine uses seeds for worms and other illnesses. These include coughs, chest pain, cancer, and amoebiasis. Such uses do not prove that treatment works or is safe. In studies, a seed compound has made gut and womb muscles contract.