Lead tree/ Subabul (Leucaena leucocephala) is a low, shrub-like, fast growing, thorn-less tropical tree that grows well under sunny conditions. The tree prefers well drained soils. It is drought tolerant as it has deep roots. It can tolerate a wide range of soils – acidic, alkaline, dry-clayey gravely soils. It can grow on sharp slopes.
It is native of Mexico and Central America and has been introduced all over the tropical world through afforestation and agro-forestry projects. The lead tree is a source of fuel wood, high-protein cattle fodder and biomass. It is planted as a wind-breaker, for checking soil erosion and for its nitrogen-fixing properties. Experiments by social-forestry and animal husbandry departments in Tamil Nadu have shown that biscuits prepared from subabul leaves add to the nutritive value of animal feed. And cattle are said to prefer the subabul biscuits to subabul leaves!! Scientists have noticed that the nutritive value of leaves of sub-species that have lower seed production is better.
Leaves of the lead tree are bi-pinnate with 10-12 pairs of oppositely arranged leaflets. Its spherical flowers are white and turn brown with time. The flowers grow in clusters on ends of branches.
The seed pods are long and flattened and turn brown on maturity. The pods twist and open to reveal neatly stored oval, glossy brown, flat seeds. The lead tree is a prolific seed producer and poses the danger of becoming an invasive species by forming thickets that crowd out natural vegetation. Seeds are dispersed by birds, rodents and cattle. The young pods are eaten in Japan and Thailand.