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Erima

Scientific name

Octomeles sumatrana. Family: Etrameleaceae

Other names

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

Description

  • Grows to 60m high and 1.5m diameter.
  • Trees are of good form, and often heavily buttressed.
  • Bark is grey-white to grey-brown with shallow fissures.

Occurrence

  • Occurs on rich, alluvial soils along rivers in:
    • Sabah
    • Sumatra
    • Papua New Guinea
    • Philippines
    • Solomon Islands.
  • Major markets are Japan and Hong Kong; however, it’s sometimes imported into Australia.

Appearance

Colour

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

Grain

  • Interlocking common, forms striped figure (pattern) on quarter-sawn stock.

Uses

  • Construction: concrete formwork, plywood.
  • Decorative: joinery, furniture.
  • Others: packing cases, coffins, matchboxes, canoes, treated shingles.

Properties

  • Density: 365kg/m3 at 12% moisture content; about 2.7m3 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 according to AS 2082—2000: Timber—Hardwood—visually stress-graded for structural purposes.
  • Joint groups: J6 unseasoned, JD6 seasoned.
  • Shrinkage to 12% MC: 4.5% (tangential), 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 impregnates with preservative; penetration of heartwood is unsatisfactory using available commercial processes.
  • Seasoning: be careful to minimise degrade by distortion and checking.
  • Hardness: very soft (rated 6 on a 6-class scale) to indent and work with hand tools.
  • Machining: be careful due to softness; keep cutting edges sharp to avoid woolliness; generally easy to work.
  • Fixing: poor rating for holding screws and nails.
  • Gluing: satisfactorily bonds using standard procedures.
  • Finishing: readily accepts paint, stain and polish; a good polish will give a silky, satin finish.

Identification features

General characteristics

  • Sapwood: white to grey-yellow with little distinction from heartwood.
  • Heartwood: light yellowish brown; darkens on exposure.
  • Texture: medium, open and uniform; grain often interlocked; moderate lustre on dressed radial surfaces.

Wood structure

  • Vessels: solitary and radial pairs; diffuse uniform distribution; medium size, visible to the unaided eye; vessel lines are common but not distinctive.
  • Parenchyma (soft tissue): not visible with hand lens.
  • Rays: moderately fine; distinct as flecks on cut radial surfaces.

Other features

  • Burning splinter test: match-size splinter burns to grey ash.

Research and resources

  • 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