Acacia mangium Willd. - A Fast Growing Tree for Tropical Plantation

Soil

A. mangium is typically a low elevation species chiefly associated with rainforest margins and disturbed sites on well-drained acid soils (pH 4.5-6.5) of low fertility. It also occurs behind mangroves, in seasonal swamps, along streams, and on well-drained flats, low ridges and mountain foot hills (Pinyopusarerk et al. 1993).

Climate

A. mangium distribution area is including the tropical warm and hot climate, either humid or wet zones characterized by a short winter dry season and high total annual rainfall. The mean maximum of the hottest month is about 30-34°C and the mean minimum of the coolest about 15-22°C. It is unsuitable in the area where the absolute minimum temperature falls below 0°C (Yan et al. 1996), so its distribution area is frost-free. In a typical location, the 50% rainfall is 2,150 mm; the 10% is 1,300 mm; and the lowest, on record, is 1,000 mm. It prefers wet sites with an annual rainfall of 1,000-4,500 mm. Prolonged dry periods will slow down the tree growth (Mergen et al. 1983). While the annual rainfall of over 2,500 mm in the Bengkoka/ Kudat region of Sabah is considered adequate for growth. Moreover, it is still affected by seasonal conditions (Pinyopusarerk et al. 1993). During the dry season, when monthly rainfall is below 100 mm and the evaporation rate exceeds 130 mm per month, the tree is under drought stress.

Vegetation types

A. mangium grows on the margins of closed forest (rain forest), in open forest and woodland, especially where there is disturbance by fire. In northern Queensland it occurs in tall forests on well-drained sites of the foothills and lowlands associated with various eucalypts and acacias. As a component of fringing vegetation on river banks, it is frequently associated with rain forest species such as Flindersia brayleyana and Cardwellia sublimis. Elsewhere, it occurs on the slightly better-drained sites within the swampy coastal plains where Melaleuca are locally dominant. Tracey (1982) described the vegetation types in humid, tropical Queensland.

In Papua New Guinea, It occurs in tall woodland and open forest, frequently in mixed associations with other Acacia, Melaleuca and Lophostemon spp. These vegetation types are described by Paijmans et al. (1971), Paijmans (1976) and Skelton (1987). At the western extremity of its range in Indonesia, A. mangium is dominant in small stands on disturbed sites in or on the fringes, closed-forest and Melaleuca spp. woodland.