Belian  (Eusideroxylon zwageri) is a hardwood tree that does not belong to dipterocarp group. This tree belongs to the family Lauraceae. Belian tree is a tree species that grows slowly and will take up to 120 years to reach 30 cm diameter. However, the seed germinates easily if given a suitable environment. This tree can grow up to 30 m height with trunk diameter reaching 1 m. Belian seeds are poisonous and very hard.

The natural distribution is Indonesia (Kalimantan and Sumatra), Malaysia (Sabah and Sarawak Borneo) and the Philippines. It is known as Belian (Sabah and Sarawak Borneo); Borneo Ironwood (European Union); Belian, Onglen, Tebelian, Tulian and Ulin (Indonesia); and Biliran, Sakian and Tambulian (Philippines). Belian tree grows in lowland forest and secondary forest with a height of 500 m above at sea level. Belian trees are usually found along riverbanks. Belian is the official tree of Sarawak.

Belian wood is categorized under heavy hardwood group and of high market value. The wood is very hard, does not rot easily and is naturally resistant because of the unique anatomical features, that it is nick-named as “Borneo ironwood”. Stumps of logged belian trees are still around decades after they were felled. Due to its density, Eusideroxylon zwageri is one of very few wood species that does not float in water. Belian wood is widely used in heavy construction and large-scale production such as for house structures, pillars, floors, and walls. Belian wood is also made into shingles for roofing. Dayak longhouse structure is usually built using belian wood. It is also valued highly as coffin wood by the Chinese.

In FRIM, flowering, belian tree can be seen near FRIM’s mosque.

Article by; Naimah CL, uploaded on 7 May 2014. The weekly weather was; rainiy with thunderstorms and temperature ranging from 24°C to 34°C.