Upuna borneensis is a monotypic plant, meaning that there is only one species in this genus. This dipterocarp species is endemic to Borneo, where it is commonly known as penyau, resak or upun batu. Upuna borneensis is a large tree with low stout buttress. The bark is dark brown, finely flaky with the inner bark not laminated. Upuna leaves are thinly coriaceous and usually somewhat bullate. This species is frequently found in mixed dipterocarp forest and the heath forest of Borneo. The wood is commonly used in heavy construction, for building and boat making The conservation status of this species is endangered. A few trees near B2 and B3 can now be seen fruiting.

Prepared by Norsham, SY. Posted on 12. October 2013. The weekly weather was 23° to 34°C and rainy.