Bangkirai (Shorea spp.)
Bangkirai (Shorea laevis) is a deciduous tree of the Dipterocarpaceae family, in the subfamily Dipterocarpoideae.
Bangkirai is traded under the name Yellow Balau, as well as other names typical for its country of origin.
Bangkirai grows in south-east Asia, on the north-west Malaysian archipelago, especially in Sulawesi (the former Celebes) and Kalimantan, as well as in India, Pakistan, Sri Lanka, Myanmar, Thailand, Laos, Vietnam, Cambodia and in the Philippines.
Description of the wood
The three to eight centimetres of sapwood is light grey to pale yellow. The heartwood has a yellowish light-brown to greenish hue when fresh that often darkens to an olive brown shade. The heartwood is not always easy to distinguish from the lighter coloured sapwood, which creates a rather homogenous overall appearance. There are, however, strong variations in colour. When exposed to the elements, Bangkirai, like many other tropical timbers, greys very quickly. Bangkirai is a heavy wood with a density of 0.92 g/cm³. Its strength, however, exceeds that of oak by some 50%.
Sawing, milling, drilling and chiselling the wood is easy enough, though difficulties can arise with fibres splitting when planing the wood due to interlocked grain. Contact with iron can lead to black stains on the wood’s surface.
The Bangkirai heartwood is resistant to wood-destroying fungi (durability class 2, acc. to DIN EN 350-2) and termites. The sapwood is not durable and its resistance to marine borers (Teredo) is insufficient. Holes from wood borers can also be found in Bangkirai.
The heartwood is practically untreatable (treatability class 4, acc. to DIN EN 350-2), the sapwood, on the other hand, is very easy to treat (treatability class 1).
Bangkirai main uses are in particularly heavy duty structures, such as for bridges, railway sleepers or floors. A growing market for this wood is being found in terrace and patio floorings and garden furniture.