Erima

Scientific name

Octomeles sumatrana. Family: Etrameleaceae

Local names

Ilimo (PNG), binuang (Philippines, Sarawak), benuang (Indonesia), fote, rara (Solomon Islands).

Description and natural occurrence

Erima can attain 60 m in height and 1.5 m in diameter. The trees are of good form, and often heavily buttressed. Bark is grey white to grey brown with shallow fissures. Erima occurs on rich, alluvial soils along riverine systems in Sabah, Sumatra, Papua New Guinea, the Philippines and the Solomon Islands. The major markets for erima are Japan and Hong Kong; however, it is sometimes imported to Australia.

Wood appearance

Colour. Heartwood is yellow-brown, occasionally with a purplish tinge. Sapwood is somewhat paler but not always clearly defined.

Grain. Interlocking grain common, forming striped figure on quarter-sawn stock.

Wood properties

Density. 365 kg/m3 at 12% moisture content; approximately 2.7 m3 of seasoned sawn timber per tonne.

Strength groups. S<7 unseasoned; SD8 seasoned.

Stress grades. Non-structural (unseasoned), F4, F5, F7, F8 (seasoned), when visually stress-graded in accordance with AS 2082-2000, Timber - hardwood - visually stress-graded for structural purposes.

Joint groups. J6 unseasoned; JD6 seasoned.

Shrinkage to 12% MC. 4.5% (tangential) and 0.13% (radial).

Unit shrinkage. 0.21% (tangential); 0.13% (radial). These values apply to timber reconditioned after seasoning.

Durability above-ground. Class 4 - life expectancy less than 7 years.

Durability in-ground. Class 4 - life expectancy less than 5 years.

Lyctine susceptibility. Sapwood is susceptible to lyctid borer attack.

Termite resistance. Not resistant.

Preservation. Sapwood readily accepts preservative impregnation. Penetration of heartwood is unsatisfactory using currently available commercial processes.

Seasoning. Careful seasoning is required to minimise degrade by distortion and checking.

Hardness. Very soft (rated 6 on a 6 class scale) in relation to indentation and ease of working with hand tools.

Machining. Care required due to softness. Cutting edges must be sharp to avoid woolliness. Generally easy to work.

Fixing. Screw and nail holding ability is rated as poor.

Gluing. Can be satisfactorily bonded using standard procedures.

Finishing. Will readily accept paint, stain and polish. With a good polish it gives a silky, satin finish.

Uses

Construction. Concrete formwork, plywood.

Decorative. Joinery, furniture.

Others. Packing cases, coffins, matchboxes, canoes, treated shingles.

Identification features

General characteristics

Sapwood. White to grey-yellow with little distinction from heatwood.

Heartwood. Light yellowish-brown. Tends to darken on exposure.

Texture. Medium, open and uniform. Grain often interlocked. Somewhat lustrous on dressed radial surfaces.

Wood structure

Vessels. Solitary and radial pairs. Diffuse uniform distribution. Medium size visible to the unaided eye. Vessel lines common but not distinctive.

Parenchyma. Not visible with hand lens.

Rays. Moderately fine. Distinct as flecks on cut radial surfaces.

Other features

Burning splinter test. A match size splinter burns to grey ash.

Further reading

Hopewell, G (ed.) 2006, 'Construction timbers in Queensland: properties and specifications for satisfactory performance of construction timbers in Queensland, Class 1 and Class 10 buildings', books 1 and 2, Department of Primary Industries and Fisheries, Brisbane.

Ilic, J 1991, 'CSIRO atlas of hardwoods', Crawford House Press, Bathurst, Australia.

Standards Australia, 2000, 'AS 2082-2000: Timber - hardwood - visually stress-graded for structural purposes', Standards Australia.

Last updated 04 August 2010