MANILA, Philippines -- For the past months, if you haven't noticed, a lot of our Narra trees planted around the city have been blooming profusely. Though the flowers are short lived, they are quite noticeable as the whole Narra tree canopy gets filled with fragrant tiny golden yellow flowers. It is only for a few days in each year we get to appreciate the floriferousness of our national tree. So majestic are its profusion of golden flowers, which easily fall to the ground after being pollinated by bees. After which, hundreds of flattened dry fruits are formed for seed dispersal.
The Narra, scientifically known as the Pterocarpus indicus, belongs to the family Fabaceae. It's a native of southeastern Asia, northern Australasia, and the western Pacific Ocean islands. Aside from the Philippines, it is also found in Cambodia, southernmost China, East Timor, Indonesia, Malaysia, Papua New Guinea, the Ryukyu Islands, the Solomon Islands, Thailand, and Vietnam.
This is a large deciduous tree that can grow up to 30 to 40 meters in height, with a trunk that can grow up to two meters in diameter. The leaves are green, about 12 to 22 centimeters long, pinnate, with five to 11 leaflets. The fragrant and yellow flowers are produced in panicles, about six to 13 cm long containing a few to numerous flowers.
Its flowering season in the Philippines is from February to May. Once pollinated, the flower forms into a dry flat fruit or a semi-orbicular pod, about two to three centimeters in diameter, surrounded by a flat four to six centimeter in diameter membranaceous wing. The latter aids the dispersal of water as it slides off the tree during the typhoon months of July and August. It contains one or two seeds, and does not split open on maturity. It was observed that it ripens within four to six years, and becomes purple when dry. The central part of the pod can be smooth (as in indica form), bristly, or have small spines (as in echinatus form).
The Narra is one of the most useful trees in the country as it provides both timber and shade. Because it is being used for timber, its conservation status was classified "vulnerable" by the International Union for the Conservation of Nature and Natural Resources.
The timber is hardwood, purplish in color, rose-scented, and termite resistant. Freshly cut wood or its saw dust characteristically produce a green sap when poured with water.
The flower is used as a honey source while leaf infusions are used as shampoos. Both flowers and leaves were said to be edible. The leaves are supposedly good for waxing and polishing brass and copper. It is also a source of kino or resin. In folk medicine, it is used to combat tumors. This property might be due to an acidic polypeptide found in its leaves that inhibit the growth of Ehrlich ascites carcinoma cells. It was also used as a diuretic in Europe during the 16th and 18th centuries.
The tree is recommended as an ornamental /shade tree. It's a common sight in parks and sidewalks. The tall, dome-shaped crown, with long, drooping branches is very attractive and the flowers look spectacular. It's also a very sturdy tree and can withstand typhoons.
The Narra can be easily propagated from seeds or large stem cuttings. In large scale production of seedlings, seeds are collected during months of July and are planted in plant nurseries.After germination, seedlings can be individually transplanted in polyethylene plastic bags and given a regular spray of dilute complete fertilizer with micronutrients for optimum growth (aside from the regular watering and weeding).
As it is often attacked by defoliating insects, it must be sprayed with insecticides. A temporary shade tree is required to nurse the Narra seedlings when they're planted in the ground. Seedlings grow very fast when they're in the soil. They become fully grown trees in just four years.