Kempas
Scientific name
Koompassia spp. principally K. malaccensis, K. excelsa. Family: Leguminosae
Other names
Impas (Sabah); Tualang (Malaysia); Tapang, Kayu raja, Mengris (Sarawak); Manggis (Philippines); Oempas (Sumatra); Ginoo (Palawan); Mengaris (Borneo)
Description
- K. excels:
- very large tree growing to 60m high
- high, wide-spreading buttresses
- clean, columnar bole (trunk) with little taper
- bark is smooth, corky and grey.
- K. malaccensis:
- usually smaller, growing to 50m tall
- more slender in form.
Occurrence
- Occurs throughout Borneo, Malaysia, the Philippines, Indonesia and Papua New Guinea.
Appearance
Colour
- Heartwood is pink when freshly cut, darkening to a deep orange-brown to red-brown after exposure.
- Sapwood is pale yellow to pink-brown and distinct from heartwood.
Grain
- Grain is interlocked, spiral or wavy.
- Texture is coarse and even, except when zones of included phloem (bark) are present.
Uses
- Decorative: parquetry flooring, panelling, furniture, shop fitting.
- Others: railway sleepers, poles, posts in Southeast Asia, but not recommended for these applications for long-term use in Australia; plywood, flooring, decking (but refer unsuitable use below); walking sticks, charcoal, shingles, chemical vats, cargo handling pallets.
- Unsuitable use: timber including phloem (bark) has reduced strength and will split when exposed to the weather, making it unsuitable for some uses, such as exposed decking.
Properties
- Density: 515-545kg/m3 at 12% moisture content; about 1.8m3 of seasoned sawn timber per tonne.
- Strength groups: G. fasciculiflora and G. leichhardtii—S6, G. dalrympleana—(S7) unseasoned, G. fasciculiflora—(SD6), G. leichhardtii—SD6, G. dalrympleana—(SD7) seasoned (brackets indicate provisional value).
- Stress grades: G. fasciculiflora and G. leichhardtii—F4, F5, F7, F8; G. dalrympleana—F4, F5, F7 (unseasoned); G. fasciculiflora, G. leichhardtii—F7, F8, F11, F14; G. dalrympleana—F5, F7, F8, F11 (seasoned) when visually stress-graded according to AS 2082—2000: Timber—Hardwood—Visually stress-graded for structural purposes.
- Joint groups: J4 unseasoned, JD4 seasoned.
- Shrinkage to 12% MC: G. leichhardtii—3.7% (tangential), 1.6% (radial).
- Unit shrinkage: G. leichhardtii—0.26% (tangential), 0.15% (radial)—these values apply to timber reconditioned after seasoning.
- Durability above-ground: Class (1) (life expectancy over 40 years).
- Durability in-ground: Class 1 (life expectancy over 25 years).
- Lyctine susceptibility: Untreated sapwood susceptible to lyctine borer attack.
- Termite resistance: not resistant.
- Preservation: sapwood readily impregnates with preservative, but penetration of heartwood is negligible using available commercial processes.
- Seasoning: air seasons very slowly; requires mild schedules for satisfactory kiln drying.
- Hardness: soft (rated 5 on a 6-class scale) to indent and work with hand tools.
- Machining: machines well due to its slightly greasy nature.
- Fixing: due to natural acidity, use non-corrosive fittings and fastenings.
- Gluing: satisfactorily bonds using standard procedures.
- Finishing: readily accepts stain, polish and paint.
Identification features
General characteristics
- Sapwood: pale yellow to pink-brown, distinct from the heartwood.
- Heartwood: orange-brown to red-brown.
- Texture: coarse and even, grain varies but rarely straight.
Wood structure
- Growth rings: indistinct.
- Vessels: diffuse porous arrangement, few and medium to moderately large; solitary or in radial groups of 2–3; frequent deposits.
- Parenchyma (soft tissue): aliform and confluent.
- Rays: fine, barely visible with the naked eye.
Other features
- Burning splinter test: match-size splinter burns to a full white ash.
- Ripple marks: present.
Research and resources
- Boland, DJ, Brooker, MIH, Chippendale, GM, Hall, N, Hyland, BPM, Johnston, RD, Kleinig, DA and Turner, JD 2006, Forest trees of Australia, 5th ed., CSIRO Publishing, Collingwood, Australia.
- Bootle, K 2005, Wood in Australia: Types, properties and uses, 2nd ed., McGraw-Hill, Sydney.
- Ilic, J 1991, CSIRO atlas of hardwoods, Crawford House Press, Bathurst, Australia.
- Queensland Government, DAF 2018, Construction timbers in Queensland: Properties and specifications for satisfactory performance of construction timbers in Queensland. Class 1 and Class 10 buildings, Books 1 & 2, Department of Agriculture and Fisheries, Brisbane.
- Standards Australia, 2000, AS 2082—2000: Timber—Hardwood—Visually stress-graded for structural purposes, Standards Australia International, Strathfield, NSW.