Neobalanocarpus heimii

Neobalanocarpus heimii, known as chengal, is a large tropical forest tree. It belongs to the Dipterocarpaceae family. Its native range spans Peninsular Thailand and Peninsular Malaysia. It grows in mixed dipterocarp forest on rolling ground. Its habitat extends from sea level to about 3,281 feet [1,000 metres]. Heavy logging has made it scarce across parts of its range. Useful Tropical Plants reports a Vulnerable listing from the 2009 IUCN assessment.

Reference profiles give a height of 131 feet [40 metres]. PFAF gives a spread of about 92 feet [28 metres]. Forest trees can exceed 197 feet [60 metres] in height. The trunk often grows straight and round. It may lack branches for 98 feet [30 metres] or more. Some trees have uneven trunks and branches near the ground. Detailed growth notes describe a slow rate, despite PFAF's medium-rate summary. One planted tree reached a trunk width of 19 inches after 40 years.

Bees and other insects pollinate the flowers. Trees do not follow a fixed yearly flowering cycle. Heavy crops of flowers and fruit come several years apart. A flowering spell lasts about three weeks. Seeds lose their ability to sprout within a short time. Fresh seed therefore needs prompt sowing under shade. It can sprout fast, with little delay from dormancy. Growers reduce that shade as the young trees gain size.

Chengal needs the warmth and moisture of a tropical climate. Its native sites average 24–27°C through the year. Annual rainfall there reaches 2,000–4,000 millimetres. PFAF places it in USDA zones 10–12. Young plants need shade and suffer from drought or harsh light. Older trees need sun. Moist soil with good drainage suits the species. It grows in sand, loam, and clay. Reported soils include those formed over granite, shale, and volcanic rock. PFAF also records tolerance of mildly acid through mildly alkaline soil.

The tree supplies hard, heavy wood for demanding building work. Uses include bridges, railway work, poles, and floors. The timber resists termites, wood borers, and fungal decay. This describes the wood, not the living tree's pest resistance. Cuts in the trunk yield a resin called damar penak. It has seen limited use in varnish making. PFAF records no known food or medicinal uses. The sources report no known hazards, but do not establish safety for eating.