Gmelina fasciculiflora, G. leichhardtii, G. dalrympleana. Family: Verbenaceae.
Beech, grey teak.
|Description and natural occurrence|
A large tree attaining a height of 40 m and a stem diameter of 1.5 m. It has a straight, slender trunk, usually circular in cross-section, often flanged at the base but not prominently buttressed. The bark is approximately 10 mm thick, light grey to dark grey and is rough and scaly with the scales generally angular but occasionally rounded.
Found in rainforests along the east coast of Australia:
G. fasciculiflora and G. dalrympleana - Rockingham Bay, Innisfail area, through to Cape York and Torres Strait Islands. G. leichhardtii - Clyde River, New South Wales to Fraser Island, Queensland. Also further north on the Eungella Range and Mt Elliot (south of Townsville).
Sawn timber of these species is not readily available. Other species of Gmelina are imported from Papua New Guinea, Solomon Islands and Fiji.
Colour. The heartwood ranges from pale straw to light grey-brown. There is no noticeable colour difference between sapwood and heartwood.
Grain. A firm, close grained, slightly greasy wood. At times it has interlocking grain. There is no pronounced figure or sheen except for a glistening effect on dressed surfaces due to tyloses in the vessel lines.
Density. 515-545 kg/m3 at 12% moisture content; approximately 1.8 m3 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 in accordance with AS 2082:2000, Timber - hardwood - visually stress-graded for structural purposes.
Joint groups. J4 unseasoned. JD4 seasoned.
Shrinkage to 12% MC. 3.7% (tangential); 1.6% (radial). These values are for G. leichhardtii only.
Unit shrinkage. 0.26% (tangential); 0.15% (radial). These values apply to timber of G. leichhardtii 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 accepts preservative impregnation but penetration of heartwood is negligible using currently available commercial processes.
Seasoning. Air seasons very slowly. Requires mild schedules for satisfactory kiln drying.
Hardness. Soft (rated 5 on a 6 class scale) in relation to indentation and ease of working with hand tools.
Machining. Machines well due to its slightly greasy nature.
Fixing. Because of the natural acidity of this species, non-corrosive fittings and fastenings should be used.
Gluing. Can be satisfactorily bonded using standard procedures.
Finishing. Will readily accept stain, polish and paint.
Decorative. Furniture, joinery, carving, turnery, picture frames. Considered the premier carving timber in Queensland.
Others. Boat building (decking, planking). Has been used for draughtsperson´s implements, templates, pattern making, cask bungs, brush stock, venetian blind slats, beehives. Was used to some extent in general building framing in the early to mid 1900s, and in flooring, lining, mouldings, joinery and cladding, but use in such applications has been very infrequent for some decades.
Sapwood. Not distinctly different in colour from heartwood.
Heartwood. Pale straw to light grey-brown.
Texture. Medium to coarse, grain often interlocked.
Growth rings. Absent.
Vessels. Medium in size, barely visible without a lens; many solitary but some in short radial multiples or groups of two or three. Vessel lines distinct. Tyloses common; whitish deposits also common in vessels and sometimes in rays; sometimes visible without a lens on longitudinal surfaces.
Parenchyma. Not visible under a lens.
Burning splinter test. Gives a full, greyish-white to buff coloured ash. Burns with a crackling noise.
Odour. Freshly cut surfaces have a faint sour odour.
Cutting. A sharp knife cuts this species across the grain with distinctive ease, leaving a very smooth surface with a soapy feel.
Boland, DJ, Brooker, MIH, Chippendale, GM, Hall, N, Hyland, BPM, Johnston, RD, Kleinig, DA and Turner, JD 2006, 'Forest trees of Australia', 5th edn, CSIRO Publishing, Collingwood Australia.
Bootle, K 2005, 'Wood in Australia: types, properties and uses', 2nd edn, McGraw-Hill, Sydney.
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 17 August 2010