Agroforestree Database

Local names:
 Burmese (ansanah,pashu-padauk), English (narra,Malay paduak,pricky narra,red sandalwood,redwood,smooth narra), Filipino (narra), French (amboine,santal rouge), Indonesian (sena,linggod,sonokembang,angsana,angsena), Lao (Sino-Tibetan) (chan dêng), Malay (

Pterocarpus indicus is a big tree, growing to 33 m in height and 2 m diameter. The trunks are usually fluted and buttressed to 7-m diameter at the base. The crowns are large and bear many long branches that are at first ascending, but eventually arch over and sometimes droop at the ends. Trees with long willowy, drooping branches are particularly conspicuous and attractive in Singapore and some parts of Malaysia and Hawaii. Elsewhere the drooping habit may not develop. In a non-seasonal humid tropical climate such as in Kuala Lumpur and Singapore, the trees are generally evergreen, but in regions with seasonal rainfall, the trees are deciduous. 

The leaves are compound-pinnate, bearing about 12 alternate leaflets. The leaflets are rather large, 7 x 3.5 to 11 x 55 cm and ovate to elliptic in shape, with a pronounced acuminate tip. 

The flowers are yellow, fragrant, and borne in large axillary panicles. When flowering, the buds do not open in daily sequence. Instead, as buds come to full size, they are kept waiting, to be triggered into opening. The opened flowers last for one day. After that, several days may pass before another batch of accumulated 'ready' buds open. The nature of the trigger is unknown. Whole avenues of such trees blooming in unpredictable synchrony making a splendid display.

The fruits, which take four months to mature, are disc-shaped, flat, and have winged margins. About 5 cm across, the fruit have a central woody-corky bulge containing several seeds (ptero-carpus means winged fruit). Unlike most legumes, the Pterocarpus fruit is indehiscent and is dispersed by wind. It also floats in water and can be water-dispersed. 

There are 1-3 seeds in each fruit.

Two distinct forms of P. indicus are recognized: P. indicus Willd. forma echinatus (Persoon) Rojo and P. indicus Willd. forma indicus. The seed portion of the pod of forma echinatus (common name pricky pear narra) is covered with distinct bristle-like spicules, while the seed of forma indicus are smooth (common name smooth narra). The distribution of pricky narra appears to be more limited than that of smooth narra. The end uses are identical.

Pterocarpus is based on the Greek words ‘pteran’ meaning a wing and, ‘karpos’ meaning’ fruit.

Ecology

The genus Pterocarpus consists of 20 species distributed throughout the tropics. P. indicus has a wide range from southern Myanmar to the Philippines and throughout the Malay Archipelago to New Guinea and the Solomon Islands. There is considerable morphological and ecological variation when viewed throughout its range, but because of extensive propagation, the trees planted in any given locality tend to be uniform. In Malaysia, its natural habitat is by the sea and along tidal creeks and rivers. Elsewhere (e.g., Papua New Guinea), it occurs in inland forests. In the Moluccas, four varieties are locally recognized, which occupy a range of habitats from the coast to submontane forests and seasonal swamps.

Native range
Cambodia, Malaysia, Myanmar, Papua New Guinea, Philippines, Singapore, Solomon Islands, United States of America, Vietnam

Tree management

P. indicus behaves like a pioneer and grows best in the open. Seedlings are slower growing than cuttings and exhibit considerable variation in vigor. A strict culling program would be necessary to ensure that only the best stocks are planted out. Rooted cuttings can be established readily on nearly all kinds of soils, from coastal sands to inland clays, in urban and garden situations, and even in quite small planting holes dug into pavements. However, establishment trials in forest areas have had mixed results and some have failed. The reasons are not clear. With a little practice, it is easy to distinguish a healthy tree by its luxuriant foliage from one that is thinly leafed and stressed. Under favorable conditions, trees in Singapore have been known to grow an average of 33 m in height and 1.55 m in girth in 11 years, or an average annual increment of 1.2 m height and 14 cm girth. Urban trees in Singapore are fertilized with compound fertilizer at the rate of 0.5, 1, and 15 kg /tree /annum in the first, second, and third years of growth. Subsequently, they get 3-5 kg per tree per annum depending on their size. The fertilizer is spread evenly on the soil under the tree crown and is applied once a year. Where the area of the soil is smaller than the crown (e.g. for trees planted in pavements and road dividers), the fertilizer is divided into two or more smaller applications. As an urban tree, P. indicus is relatively wind-firm and seldom suffers branch breakage. Trees of all sizes and ages easily regenerate new shoots when lopped or pollarded. In Papua New Guinea, logged forest trees readily regenerate new plants from the roots.

The seeds are difficult to extract, but will germinate readily through built-in weaknesses in the fruit wall. There is therefore no advantage of extracting the seeds because the germination time and percentage are practically the same between whole fruits and extracted seeds.

The genus Pterocarpus consists of 20 species distributed throughout the tropics. P. indicus has a wide range from southern Myanmar to the Philippines and throughout the Malay Archipelago to New Guinea and the Solomon Islands. There is considerable morphological and ecological variation when viewed throughout its range, but because of extensive propagation, the trees planted in any given locality tend to be uniform. In Malaysia, its natural habitat is by the sea and along tidal creeks and rivers. Elsewhere (e.g., Papua New Guinea), it occurs in inland forests. In the Moluccas, four varieties are locally recognized, which occupy a range of habitats from the coast to submontane forests and seasonal swamps.

P. indicus may be propagated by seed, which germinate in 8-100 days, but the initial growth of seedlings and saplings is relatively slow. 
Propagation by cuttings is preferred, especially for ornamental planting. P. indicus is unique among big timber trees in that the capacity for rooting of stem cuttings is not lost with age. Stem cuttings can be taken from trees of any age and size. Cuttings of diameter 6 cm or larger will root better than cuttings of smaller diameter. Young leaf-bearing stems will not root at all.  For roadside planting, the cuttings used are in the form of stakes 15-3 m long and as much as 10 cm diameter. Such stakes produce up to 10 radiating shoots at the top, making a symmetrical crown very quickly, above pedestrian height. Few species can match P. indicus in the ability to produce well-crowned instant trees within one or two years. If large stakes fail to root, it is usually because of water-logging or accidental movement of the stakes during the tender rooting period. These problems can be avoided by rooting the stakes in loamy soil in large well-drained containers, while tied securely to a simple supporting framework. The stakes root in about 3 months and can be reduced to as short as 10 cm length, but such cuttings would take longer to develop into trees.

 The young leaves and flowers are said to be eaten and those who eat them probably concentrate such meals during the leaf flush and flowering periods.

Apiculture: The flowers are a honey source.

Although the wood is not necessarily recommended as firewood, it certainly could be used for firewood. Some Pterocarpus burn green.

Timber:  The timbers of all species of Pterocarpus are highly valued. P. indicus timber is moderately hard (.52 specific gravity), moderately heavy, easy to work, pleasantly rose-scented, takes a fine polish, develops a range of rich colors from yellow to red, and has conspicuous growth rings, which impart a fine figure to the wood. Remarkably, such growth rings are developed even in the non-seasonal humid tropics. Traditionally, Pterocarpus has been so much in demand for cabinet class furniture that nearly everywhere its existence in the wild is precarious. In the Philippines, it is the national tree and the favorite timber for the manufacture of fine furniture, cabinetry, cart wheels, carving, construction and musical instruments. The heartwood is brick red to golden brown in color but ages to a dull brown leather colour. The highly prized Amboyna burl, one of the rarest and most valued wood products in the world, is marked with little twisted curls and knots in a manner more varied than bird's-eye maple. There is a distinctive sweet smell when working the wood. The more red the wood, the heavier it is, but an average density might be 720 kg/m³. It is little used for ornamental turning, but because the burl is so exquisitely figured, it makes a nice compliment to a piece to use it for finials or perhaps a cabochon-like inlay on a flat box top. 

Shade or shelter: In Malaysia, it has been planted as a shade tree for at least 200 years. 

Tannin or dyestuff: The wood gives a reddish dye, more fugitive than that of Pterocarpus santolinus. It is also a source of kino.

Medicine: The red latex is used in folk remedies for tumors, the plant for cancers, especially of the mouth. The leaves are reported to significantly inhibit the growth of Ehrlich ascites carcinoma cells in mice. Malayans apply the kino to sores of the mouth, and the root juice to syphilis. Javanese apply the young leaves to boils, prickly heat and ulcers. In the Carolyn Islands, finely powdered leaves are applied to a ruptured vagina. The kino, containing kinotannic acid, was once administered in diarrhoea, often combined with opium. Reported to be antibilious, emetic, and sternutatory, Malay padauk is a folk remedy for bladder ailments, diarrhoea, dropsy, headache, sores, stones, thrush, and tumors of the abdomen.

Nitrogen fixing: Studies in Hawaii, Malaysia, the Philippines, and Singapore, indicate that the species fixes nitrogen.

Ornamental: It flowers gregariously, the whole crown becoming as though painted yellow. In Singapore, it is practically the symbol of that country’s garden city planting program; many avenues are graced by this attractive tree. Planted occasionally in Puerto Rico for shade and ornament.