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Slash pine

Scientific name

Pinus elliottii var. elliottii, P. elliottii var. densa. Family: Pinaceae

Other names

Florida pine; yellow pine (in south-eastern United States)

Description

  • Medium-sized tree.
  • Grows 30–35m high and stem to 0.7m diameter.
  • Branches are usually large and spreading.
  • Bark is grey to red-brown, thick, rough, and deeply fissured.
  • Bark sheds in small scales.

Occurrence

  • Grown in plantations in the coastal regions of northern New South Wales to Rockhampton, Queensland.
  • Introduced into Queensland in the late 1920s.
  • Native to south-east United States from South Carolina to Florida and west to Louisiana.

Appearance

Colour

  • Heartwood is reddish brown to shades of yellow.
  • Sapwood is usually pale yellow to yellow.

Grain

  • Generally straight.
  • Obvious difference in colour between earlywood and latewood results in a very distinctive figure (pattern) when back-sawn.

Uses

Engineering

  • Preservative-impregnated poles for pole-frame construction, power poles, piles.

Construction

  • General purpose softwood used as dressed seasoned timber in general house framing, flooring, lining, joinery, mouldings, and laminated beams.
  • Preservative impregnated for external cladding, decking, fascia and barge boards; and seasoned sawn or round forms in fencing, pergolas, landscaping, retaining walls and playground equipment.
  • Structural plywood and reconstituted panel products such as particleboard and medium-density fibreboard.

Decorative

  • Furniture, plywood, joinery, turning.

Others

  • Scaffold planks, wood wool, paper products.

Properties

  • Density: 625kg/m3 at 12% moisture content; about 1.6m3 of seasoned sawn timber per tonne.
  • Strength groups: Pinus elliottii var. elliottii—S5 unseasoned, SD5 seasoned. P. elliottii var. densa—(S5) unseasoned, (SD5) seasoned (brackets indicate provisional value).
  • Stress grades: F4, F5, F7, F8, F11 (unseasoned); F7, F8, F11, F14, F17 (seasoned) when visually stress-graded according to AS 2858—2008: Timber—Softwood—Visually stress-graded for structural purposes.
  • Joint groups: J4 unseasoned, JD3 seasoned.
  • Shrinkage to 12% MC: 4.8% (tangential), 3.0% (radial).
  • Unit shrinkage: 0.29% (tangential), 0.20% (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 not susceptible to lyctid borer attack.
  • Termite resistance: resistant.
  • Preservation: immature plantation-grown stems are almost entirely sapwood, which typically comprises more than 50% of the stem radius even in mature plantations; sapwood readily impregnates with commercial preservative but the heartwood can’t be adequately treated using available commercial processes.
  • Seasoning: to avoid distortion, dry framing sizes at high temperatures; boards may be air-dried or kiln-dried at conventional or high temperatures.
  • Hardness: firm (rated 4 on a 6-class scale) to indent and work with hand tools.
  • Machining: keep planer blades sharp when dressing to avoid compressing the softer earlywood and causing ridged surfaces.
  • Fixing: nails tend to follow the growth rings due to deflection by latewood bands; be careful when using standard fastening and fittings; use a nailing gun for good results.
  • Gluing: glue can absorb differently between earlywood and latewood, but this rarely causes problems.
  • Finishing: be careful when you select timber for finishing and when you prepare surfaces for paint and varnish due to the high resin content of some material and earlywood/latewood ridging of dressed timber.

Identification features

General characteristics

  • Sapwood: pale yellow to yellow.
  • Heartwood: reddish brown to shades of yellow.
  • Texture: non-uniform, alternating bands of earlywood and latewood; transition from earlywood to latewood is moderately abrupt; grain is straight; knots usually present in constructional timber grades.

Wood structure

  • Growth rings: clearly visible due to the latewood forming a dense, dark band; false annual rings are occasionally present.
  • Vessels: absent.
  • Resin canals: numerous, prominent as lines on dressed longitudinal surfaces.
  • Rays: fine, visible with a lens.
  • Parenchyma: absent

Other features

  • Odour: wood, generally, has a strong resinous odour.

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 2858—2008: Timber—Softwood—Visually stress-graded for structural purposes, Standards Australia International, Strathfield, NSW.