Agroforestree Database

Local names:
 English (Papua New Guinea walnut,Pacific walnut,New Guinea walnut,Argus pheasant tree), Filipino (dao), German (Drachenapfel), Indonesian (dahu), Malay (sengkuang), Thai (sang-kuan,phrachao ha phra ong,ka-kho,dao), Vietnamese (s[aas]u)

Dracontomelon dao is a large tree up to 45(-55) m tall, bole branchless for up to 20(-25) m, up to 100(-150) cm in diameter, with narrow buttresses up to 6 m high, bark surface irregularly scaly, greyish-brown with brown or greenish patches, inner bark pink or red.

Leaves arranged spirally, crowded towards the ends of twigs, large, imparipinnate; leaf rachis 6-25(-44) cm long, leaflets (7-)9-19, alternate to opposite, 4.5-20(-27) cm x 2-7(-10.5) cm, glabrous or sometimes pubescent below, with hairy domatia.

Inflorescence axillary or terminal, paniculate; bracts and bracteoles caducous; flowers bisexual, actinomorphic, 5-merous, slightly fragrant, white to greenish-white, 7-10 mm long, in panicles of up to 50 cm long; petals valvate but imbricate at the apical part, puberulous outside or on both surfaces, or glabrous; stamens 10, in 2 whorls, those opposite the calyx lobes longer than those alternating with them, filaments glabrous, anthers dorsified, disk intrastaminal, puberulous but glabrescent, or glabrous; pistil composed of 5 carpels which are free but connate at base and apically, ovary superior, 5-celled with a single ovule in each cell, styles 5, stigma capitate with the stigmatic tissue lateral.

Fruit a drupe, globose, 5-celled, or seemingly 1-celled by abortion, each cell with a distinct operculum, endocarp woody and hard.

Seed pendulous from an apical, axial placenta.

The specific epithet is the common name for the species in Filipino.

Ecology

D. dao occurs in primary or secondary, evergreen or semi-deciduous (monsoon) forest at low altitude 0-500(-1 000) m, in areas with high rainfall or less frequently in areas with a short dry season where it is deciduous or partly so. It is found scattered on well drained to poorly drained clayey to stony soils, mainly alluvial flats and in swampy areas.

Native range
Cambodia, China, India, Indonesia, Malaysia, Myanmar, Papua New Guinea, Philippines, Solomon Islands, Thailand

Tree management

Young trees reach a height of 3-4 m after 2 years and 6.5 m after 5.5 years. In Java, trial plantations are established at a spacing of 1 m x 3 m and the canopy closes after 8 years. The tree tolerates shade and since natural pruning is good, artificial pruning is seldom necessary.

Seed should be extracted immediately after the fleshy fruits have been collected. Pulp and seed can be separated by maceration. There are 520-620 seeds/kg. Seeds are recalcitrant and there is a 33 % germination when sown fresh and no germination at all after 6 months under ambient conditions in Java. In Malaysia, 85-95 % of fresh seeds germinate after 28-67 days.

D. dao occurs in primary or secondary, evergreen or semi-deciduous (monsoon) forest at low altitude 0-500(-1 000) m, in areas with high rainfall or less frequently in areas with a short dry season where it is deciduous or partly so. It is found scattered on well drained to poorly drained clayey to stony soils, mainly alluvial flats and in swampy areas.

Propagation is usually by seed. Trees can also be established by direct sowing and wildings as it regenerates easily.

  The fruit is edible but considered inferior and mostly eaten by children, the kernel of the seed is also edible. Flowers and leaves are cooked and eaten as a vegetable in Papua New Guinea, and used as food flavouring in the Moluccas.

The tree is used for firewood.

Timber:  D. dao is the main source of dao timber, density of the wood is (330-) 370-790 kg/cu m at 15 % moisture content. The heartwood is greyish, greenish-yellow to walnut brown, often with irregular dark brown to nearly black bands or fine streaks, the more or less clearly differentiated sapwood is pale yellow with pinkish or greyish tinge, up to 10 cm wide. Grain straight or interlocked, texture moderately coarse to coarse and even, lustrous, wavy grain sometimes producing a coarse fiddle-back figure. It is used for veneers, furniture, plywood, interior trim and light frames.

Medicine:  The bark is used against dysentery, leaves and flowers are also employed in traditional medicine.

Ornamental:  The tree is planted as an ornamental in roadside plantings.