Acacia mangium Seeds | Mangium
LATIN NAME: Acacia mangium
COMMON NAME: Mangium, Black Wattle
Plant Profile
Acacia mangium is a fast-growing tropical tree of the legume family, twenty-five to thirty metres tall, with a straight trunk and a canopy of phyllodes: flattened leaf stalks that function as leaves and hang vertically to reduce glare. True leaves appear only on seedlings.
It is native to north Queensland, Papua New Guinea and the eastern Indonesian islands, and it has been planted across South-East Asia and southern China as a pulpwood and reclamation species. The flowers are cream rods, and the seed pods curl tightly when they dry. The bark is rough and grey-brown, and the tree is often recognisable from a distance by the pale underside of its hanging foliage.
Science & Biotechnology
The phyllodes are an adaptation to strong light and poor soils, and they give the tree its characteristic drooping, dark green canopy. Like many acacias, it fixes nitrogen through rhizobia in root nodules, which is why it can grow on degraded land and why it is used to improve soil before other crops.
The species is also an aggressive seeder. A mature tree can produce tens of thousands of hard-coated seeds that remain viable in the soil for years, germinating after fire or disturbance. In parts of Indonesia and Malaysia it has become a weed of degraded grassland, which is the risk that comes with its vigour.
Uses & Benefits
The wood is pale, light and short-fibred, and it is grown mainly for pulp and for particleboard. It is also used for furniture cores, for pallets and for fuel, and the bark yields tannin.
The tree is planted for shade in plantations, for erosion control and for rehabilitation of mine spoil. It is not a food crop, though the seed is eaten in some places after prolonged boiling, and the flowers are a minor source of honey. The wood is also used for charcoal and for mine props, and the tree is planted to shade coffee and cocoa in some regions.
Growing from Seed
Seed has a hard coat and needs treatment: pour near-boiling water over it and leave to soak for twelve hours, or nick the coat. Sow at 25 to 30°C and germination is rapid and heavy.
Seedlings are planted out at three to four months, at three by three metres, and they grow extremely fast in the first three years. The tree tolerates acid, infertile and waterlogged soil but needs full sun. Because of its weed potential, it should not be planted near intact forest or where seed can spread into unmanaged land. Seed keeps for years in a dry jar, which is part of the reason the species spreads so easily after disturbance.
Our Take
A plantation workhorse with real weed potential, best kept in managed blocks and never planted loose near bushland. A plantation workhorse with real weed potential, best kept in managed blocks and never planted loose near bushland or watercourses.
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