Introduction |
The Standard Malaysian Name for the heavy timbers of
Hopea spp. (Dipterocarpaceae). Vernacular names applied include giam
(Peninsular Malaysia) with various epithets, selangan (Sabah and
Sarawak) with various epithets and other localised names too numerous to
list here. Major species include H. ferrea, H. helferi, H. nutans, H.
pentanervia and H. semicuneata. The sapwood is yellow and is poorly
defined from the heartwood, which is yellow with a greenish tinge when
fresh and turns deep red-brown on exposure. Also known as Koki:r
(Cambodia); Balau (Indonesia); Hin, Mai khaen fay and Mai la en (Laos);
Thingyan (Myanmar); Heavy hopea (Papua New Guinea); Saplungan and Yakal
(Philippines); Krabok-krang, Lao Tao, Takian Hin, Takian-Nu and
Takian-rak (Thailand); and Sao xanh (Vietnam). |
Botanical Name |
- |
Natural Durability |
Only one species of giam (H. nutans) has been
subjected to the graveyard test to determine its natural durability
under exposed conditions. Of the 59 samples tested (dimension 50 mm x 50
mm x 600 mm), all were still serviceable after two years; only 5 per
cent of the test sticks were destroyed in the eighth year and 80 per
cent of the test sticks were found to be still serviceable after the
fourteenth year. Compared to other Heavy Malaysian Hardwoods tested
under the same conditions e.g. chengal, balau and merbau, this
particular species of giam seems to be more durable. The timber has
therefore, been classified as very durable under Malaysian conditions
(Jackson, 1960). |
Uses |
The timber is suitable for all heavy construction,
marine construction, ship and boat building (keels, keelsons and
framework), posts, beams, joists, rafters, flooring (heavy traffic),
decking, fender supports, mallets, vehicle bodies (framework and floor
boards), heavy duty furniture, cooling tower (structural members),
power-line poles, railway sleepers, columns (heavy duty), door and
window frames and sills, tool handles (impact), telegraphic and power
transmission posts and cross arms, container floor boards and heavy duty
laboratory benches. |
Texture |
Texture is very fine to moderately fine and even, with deeply interlocked grain. |
Density |
The timber is a Heavy Hardwood with a density of 865-1,220 kg/m3 air dry. |
Shrinkage |
Shrinkage is average to high, with radial shrinkage ranging 1.4-2% and tangential shrinkage ranging 2.6-4.4%. |
Defect |
Though the form of the trees is sometimes poor, giam
timber is generally free from major defects. Minor defects of the timber
include occasional attack by 'pin' hole, powder post and longicorn
beetles. Resin and bark pockets may also be found in the timber. The
sapwood, which is light in colour, is sometimes attacked by sap-stain
fungi. |