Dipterocarpus alatus aka Hairy Leaf Apitong

Dipterocarpus alatus is a tree that stays green year-round. It belongs to the Dipterocarpaceae family. Common names include apitong and gurjun balsam. It grows in Bangladesh, Myanmar, Thailand, Laos, Vietnam, and Cambodia. Reports list the Philippines too. Whether it is native there is not clear. It grows by rivers and in mixed dipterocarp forests. It also grows in forests that stay green or shed leaves. Loss of its habitat puts the tree at risk. Useful Tropical Plants cites the 2009 IUCN assessment, which lists it as Endangered.

This large tree needs room for its broad crown. PFAF gives a garden height of 98 feet [30 metres]. It gives a spread of 66 feet [20 metres]. Other accounts give heights of 131 feet [40 metres]. A few trees reach 180 feet [55 metres]. Its crown forms an umbrella shape above a straight trunk. The trunk can reach 4.9 feet [1.5 metres] across. Its lower 66 feet [20 metres] may lack branches. PFAF says the tree grows slowly.

This tree grows in tropical lowlands below 1,640 feet [500 metres]. It grows best with daytime warmth of 22–32°C. A temperature of 5°C may kill it. PFAF lists USDA zones 10–12. Young plants can live in deep shade for years. The species also grows in light shade or full sun. It prefers moist soil that drains well. It can grow in sand, loam, and clay. Soil can be slightly acid, neutral, or slightly alkaline. Sources give different rainfall needs, but both describe wet climates.

People plant it for shade along streets in Vietnam. Foresters use it to help bring woodland back to damaged land. It takes root in soil that rivers leave behind. It can improve soil beneath its crown. Growers sometimes plant it among fruit trees. People use its wood to build and make furniture. Tapping its trunk yields an oily resin. People use this for light, paint, varnish, and ink. They also use it to keep water out. Sow fresh seed soon; it soon loses its power to sprout. Seeds can start to sprout within four to seven days at 25°C.

PFAF lists no known food uses for this species. Traditional remedies use its resin in rubs to ease pain. They also use it in wound dressings. Some mix the resin with beeswax. Reports also describe using young bark for rheumatism and liver complaints. These records show traditional use, not proof that treatment is safe. Wood dust can cause boils, so handling it poses a health risk.