Intsia bijuga aka Johnstone River Teak

Intsia bijuga is a tropical tree in the pea family, Fabaceae. Its common names include Moluccan ironwood, ipil, and kwila. Its native range runs from Zanzibar to the western Pacific. It grows across tropical Asia, northern Australia, and many Pacific islands. It lives on sand beaches, coral shores, and inland flood sites. It also grows where mangrove woods meet inland forest.

This tree has a broad crown and a buttressed trunk. One garden reference gives a height and width of 82 feet [25 metres]. Other accounts describe heights of 115–131 feet [35–40 metres]. One summary gives an extreme of 164 feet [50 metres]. Its trunk can reach 5–7 feet [1.5–2 metres] across. The leaves are glossy green, and the tree stays mostly evergreen. Its flowers have a scent and attract bees and other insects. It forms seedpods with hard-coated seeds. Sources differ on growth speed, from slow to moderately fast.

This species needs a warm climate and cannot cope with frost. PFAF places it in USDA zones 11–12. It grows best in full sun but accepts some shade. Young seedlings need strong light. It prefers fertile soil that drains very well. Sand and loam suit it, including soils with some salt. Mildly acid soil suits it best, though it accepts other pH levels. It thrives with ample rain, but established trees withstand some drought. Salt spray and coastal winds cause it little trouble.

The wide crown gives shade in streets and large grounds. Coastal sites suit its wind and salt tolerance. Its roots help hold soil on worn slopes and creek edges. People plant it for windbreaks and soil repair. Its timber has high value, and heavy wild harvesting threatens remaining stands. Useful Tropical Plants cites a Vulnerable listing from the 2009 IUCN assessment. The tree can fix nitrogen. Its leaves also supply mulch as they fall and break down.

People use the bark in traditional treatments for several ailments. These include diarrhoea, dysentery, rheumatism, and urinary complaints. The seeds serve as food during shortages, but need careful preparation. Reports describe soaking them in salt water, then boiling them. PFAF also warns that the fruit may be poisonous. That warning limits any claim that the whole plant is safe. The supplied accounts give no specific pest or disease problems.