Conocarpus erectus

Species

C. erectus

Families

Combretaceae

Local Names

Knair

Genus

Conocarpus

Native/Introduced

Introduced to Pakistan

DNA Barcode

Description

Conocarpus erectus is an evergreen shrub or tree with a spreading crown; it can grow 4 - 20 metres tall. The bole can be 20cm in diameter. There are two forms of the tree, one with green leaves and one with silvery leaves. The wood is harvested from the wild for fuel and tannins. The tree is also widely grown as an ornamental, for land reclamation and as a hedge.
A widespread species, tolerant of a wide range of habitats. Its population is decreasing because of loss of habitat, but it is not considered to be at risk. It is classified as 'Least Concern' in the IUCN Red List of Threatened Species (2011). Coastal areas of tropical America in Florida through the Caribbean and C. America to Brazil and Peru. Coasts of western Africa from Senegal to Angola.


Habitat
Salt and brackish water in mud flats of tidal zones, usually on the landward side of the mangrove forests. It often forms an inland zone at a slightly higher altitude above the high tide level. A plant of the moist, lowland tropics, where it is found at elevations up to 200 metres. It grows best in areas where annual daytime temperatures are within the range 20 - 30°c, but can tolerate 10 - 38°c. It prefers a mean annual rainfall in the range 1,500 - 2,500mm, but tolerates 1,000 - 3,000mm.
Requires a position in full sun. A very amenable plant, able to thrive on dry soils away from the mangroves; marl-filled land with a high brackish water table; and poor, sandy soils. Established plants are very drought tolerant. Prefers a pH in the range 5 - 7, tolerating 5 - 7.5. The plant can form extensive thickets by sprawling and rooting where the stems touch the ground.
There are two distinct forms of this tree, both of which can be found growing side by side in the wild. The species has green leaves, whilst var sericeus (known as silver buttonwood) has silvery leaves. The fruits float in water, thus allowing the seeds to be dispersed more widely. The bark contains tannins and has medicinal properties. Probably as an astringent.


Agroforestry Uses:
    Amenable to trimming, and easily propagated by cuttings of large wood, the plant can be grown as a hedge or screen.
    Because it can be grown from large cuttings, it has been planted as a living hedge in some water-retentive areas.
    Used in land reclamation schemes, especially on sandy and saline soils. It has become a particularly popular species in the United Arab Emirates, where it is being used to desalinate the desert and help to green it.


Other Uses
The leaves and bark are a source of tannins that can also be used for dyeing purposes. The heartwood is yellow-brown to dark brown; the thin band of sapwood light brown to nearly white. The texture is fine; the grain very fine. The wood is very heavy; hard; very strong; tough; very durable, even in contact with the soil. It takes a good polish. It is susceptible to dry-wood termites. The wood is used for fence posts, crossties, turnery and boat building. The wood keeps almost indefinitely, and is highly prized as timber, being used for carpentry work, poles, rafters, boat curves and cabinet work. The wood makes a very good fuel, burning slowly. It also makes an excellent charcoal.