leucaena

Leucaena is a genus of tropical and subtropical trees and shrubs in the legume family, Fabaceae. The best known species is Leucaena leucocephala, commonly called lead tree, ipil-ipil or huizache. The genus includes several species, all adapted to warm climates. Leucaena leucocephala is a fast-growing, drought-tolerant nitrogen-fixing tree that is widely cultivated for forage and soil improvement.

Description: Leaves are pinnate with dozens to hundreds of small leaflets; flowers are small, white or pale cream, arranged in elongated, bottlebrush-like inflorescences; fruit is a flat pod containing several seeds. The tree reaches several meters, up to 7-20 meters.

Ecology and distribution: Native to southern Mexico and Central America; now naturalized across the tropics and subtropics, including Africa, Asia, the Caribbean, and Pacific islands. It tolerates poor soils and drought. It forms symbiotic nitrogen-fixing associations with rhizobia, improving soil fertility.

Uses: Livestock forage and feed; leaves high in protein; used as green manure, cover crop, nitrogen fixer; wood for fuel, charcoal, timber; shade and erosion control.

Toxicity and safety: Contains mimosine, a toxic non-protein amino acid. In ruminants, detoxification can occur in the rumen but toxicity may occur if feed is high in mimosine or if animals are non-ruminants or young; signs include hair loss, goitre, reduced production. Processing or dietary strategies can mitigate risk; consult local guidelines.

Invasiveness and management: In some regions, leucaena can become naturalized or invasive, forming dense stands that outcompete native vegetation. Seed dispersal and root suckers contribute to spread; management and monitoring recommended where appropriate.