Moluccan ironwood  (Intsia bijuga)

Classified as Vulnerable (VU) on the IUCN Red List (1).

A highly-valued commercial tree, the Moluccan hardwood is intensively harvested for its timber, as it is one of the most decay-resistant woods known (3) (4). This large, deciduous tree is also known for its distinctive crown of outward stretching branches and steep, rounded buttresses, which on fully grown trees can exceed four metres in height (2) (5). The white to pink-red flowers are arranged into a dense inflorescence and numerous broad, tear-shaped, shiny, light green leaves extend from each stem in a feather-like structure (4) (5). The fruit of the Moluccan hardwood is a pear- or oblong-shaped, thick, rigid pod that measures up to 10 centimetres in length and usually contains one to nine dull brown, large, flattened seeds (4) (5).

The Moluccan ironwood is found in South and Southeast Asia, from India through to Indonesia, as well as in Papa New Guinea, the Philippines, Australia and numerous Pacific and Indian Ocean islands, including American Samao, Madagascar and the Chagos Islands (1) (3) (6).

The Moluccan ironwood inhabits lowland tropical rainforests and is usually found around sea level, often in a zone behind mangrove forests and areas bordering swamps, rivers and floodplains (1) (2) (3). It is also found on sand and coral beaches, as well as inland areas, and will grow in both primary and secondary forests up to 600 metres above sea level (3) (5).

The Moluccan ironwood is a slow growing, deciduous tree that despite initial rapid growth takes up to 80 years to mature (4). It sheds its leaves annually and remains bare for a few days afterwards. It is a monoecious species meaning that each plant has both male and female flowers. The flowers emit a strong scent and insects, such as bees, birds and the wind are all considered to be major pollinators (4) (5).  The Moluccan ironwood fruits all-year round (5).

The Moluccan ironwood has a long history of exploitation for its valuable, strong, attractive wood, which has a variety of uses in construction, and for its bark and leaves which are used in traditional medicines (3). However, it has been so heavily harvested that today few dense, natural stands of the species remain (1) (6). It is now almost extinct in Sabah, Malaysia, and is uncommon on Peninsular Malaysia, and rarely reaches commercial size there, although it is more common in Papua New Guinea and Indonesia (1) (3) (6). There have also been few efforts to develop commercial plantations, meaning the demand for the species’ timber can only be met by removing trees from the wild (1) (6).  

While there are no known conservation measures in place for the Moluccan ironwood, permission is required to harvest it in the Philippines. It is also found in a number of protected reserves across its range, including the Ujung Kulong National Park in Java, Indonesia (3). The Moluccan ironwood is easily grown from seeds, saplings or stump cuttings, thereby providing the potential for it to be grown in commercial plantations, which would decrease the harvesting pressure on wild trees (4).

ARKive is supported by OTEP, a joint programme of funding from the UK FCO and DFID which provides support to address priority environmental issues in the Overseas Territories, and Defra

For more information on tree conservation, see:

• The Global Trees Campaign: 
  http://www.globaltrees.org/

To find out more about conservation on the Chagos Islands, see:

• Procter, D. and Fleming, L.V. (1999) Biodiversity: the UK Overseas Territories. Joint Nature Conservation Committee, Peterborough, UK.
• Sheppard, C. and Spalding, M. (2003) Chagos Conservation Management Plan. British Indian Ocean Territory Administration, Foreign and Commonwealth Office, London.