Acacia mangiumNews 30th June, 2016 64 Likes No Comments
Acacia mangium is native to Australia; Indonesia; and Papua, New Guinea, but now has a wider latitudinal and longitudinal range. Introduced in Costa Rica, Bangladesh, Cameroon, Puerto Rico, Hawaii, Malaysia, Nepal, and the Philippines, Acacia mangium is a low-elevation species associated with rain forest margins and disturbed, well-drained acid soils (pH 4.5–6.5). Altitudinal range is from sea level to more than 100 meters (328 feet), with an upper limit of 780 meters (2560 feet). It is typically found in the humid, tropical lowland climatic zone characterized by a short dry season and a mean annual rainfall between 1500 to 3000 mm (59 to 118 in.). Acacia mangium can tolerate a minimum annual rainfall of 1000 mm (39.4 in.). Mean monthly temperatures tolerated range from a low of 13 to 21ºC (55–70 ºF) to a high of 25 to 32ºC (77–90ºF). Though considered an evergreen species, A. mangium does not grow continuously throughout the year; growth seems to slow or cease in response to the combination of low rainfall and cool temperatures (winrock.org).
It is a tree up to 30 m (98.4 feet) in height, and the diameter rarely exceeds 50 cm (20 in.) DBH. The trunk can be unbranched for more than half of the total tree height; it is sometimes fluted at the base. The bark is rough and furrowed, either grey or brown. The dark green, glabrous (lacking hair) leaves are large, up to 25 cm (9.8 in.) long, 3 to 10 cm (1.2–3.94 in.) broad, normally with four main longitudinal nerves; on juvenile trees the leaves are compound. The flowers have a mild, sweet fragrance; they are white or creamy, in rather loose spikes up to 10 cm (3.94 in.) long, single or in pairs in the upper leaf corners. The seed pods are broad, linear, and irregularly coiled, and the seeds are shiny dark brown to black. Seeds mature 6 to 7 months after flowering (www.dfsc.dk).
Since A. mangium can grow on marginal soils, many farmers choose to plant this species to improve soil fertility of fallowed fields or pastures. Mangium trees with diameters of 7 cm (2.76 in.) are fire resistant, so in plantations they can be used as fire breaks. This species has been grown in plantations in Costa Rica since 1979 when CATIE (Tropical Agriculture Research and Higher Education Center) introduced the species with a research proposal, and a medium to fast growth is reported with 3.5 m average height growth and 5.4 cm average diameter growth per year. Usually the species branches out, so pruning is essential at an early stage (Coseforma).
Acacia plantation forests have increasingly played an important role in Indonesia and other South East Asian countries to supply wood material for pulp and paper industries. PT. Musi Hutan Persada located in South Sumatra, Indonesia, began to establish its Acacia plantations in 1990 on unproductive sites formerly dominated by alang-alang (Imperata cylindrica) grasslands. A total of approximately 200,000 ha have been planted mainly with Acacia mangium. The species is selected due to its good characteristics; it is adapted to and grows well on inherently acid and poor soils dominating the company’s plantation sites. Its wood is excellent for pulp and paper as well as furniture. While the importance of using genetically improved seed has been highly recognized by the company, the first-rotation plantations were established using unimproved local seed due to unavailability of a large amount of improved seed during this period. The better quality seeds have subsequently become available from the tree improvement program set up by the company. The combined use of improved seed with proper silvicultural practices has been employed with the objective of having high plantation productivity.