Castanopsis costata, locally known as Berangan and Berangan Bukit in Malay, is an evergreen tree that can grow up to 36 m tall and 80 cm in diameter. The whitish bark is smooth or scaly or rarely flaky while the yellowish inner bark is fibrous. Its sapwood is in pale yellow colour. The twigs are pubescent (hairy) when young and glabrescent (becoming hairless) later. The stipules are linear and triangular. The leaves are coriaceous (having the texture of leather) or sometimes thick-coriaceous and glabrous (smooth) on the surface. The male flowers are arranged in clusters of 2 to 3 or sometimes solitary along the rachis while the female flowers are arranged in clusters of 3 or sometimes solitary along the rachis. Both male and female flowers have acute perianth lobes. There are 2 to 3 conical seeds with thin wall in each cupule (Soepadmo & Saw, 2000).

Castanopsis costata can be found in Sumatra, Peninsular Malaysia, Java and Borneo but more common and widely distributed in Sabah, Sarawak, Brunei and Kalimantan. This tree grows in the primary lowland mixed dipterocarp forest to montane forest at elevations up to 1900 m. The seeds are edible which can be a food source in times of shortage (Soepadmo & Saw, 2000).