Kauri, Queensland

Queensland kauri is an Australian native softwood with a fine even texture, pale cream to light or pinkish brown heartwood and a straight grain.

Other Names

South Queensland Kauri, Dundathu Pine, Black Kauri, Blue Kauri, Mountain Kauri, North Queensland Kauri, Bull Kauri, Agathis palmerstonii, Agathis atropurpuea, Agathis microstachya

Botanical Name

Agathis robusta

Common Form
Sawn
Species Type

Queensland kauri pine is one of Australia's native softwood timber species. Its species name, Agathis robusta, is derived from its cones, which look like a ball of thread (agathis), combined with its vigorous growth (robusta). An attractive timber suited to many indoor uses, including fine cabinetry, the Queensland kauri was heavily logged in the early years of European settlement. Large trees are therefore more rare now than in pre-European times; despite this, the species is not classified as endangered.

Queensland kauri occurs in two localities: in southern Queensland on Fraser Island and around Maryborough; and there is a northern population on the Atherton Tableland west of Cairns. Although these two populations were once given different scientific names (A. robusta in the south and A. spathulata in the north), they have since been discovered to be the same species. Queensland kauri is a large, coniferous tree with a straight trunk, growing to a height of 25-40 metres with a trunk diameter of between 100 - 200cm. The trunk is clear of branches for over half its length. The characteristically straight and symmetrical trees are covered with smooth to flaky grey-brown bark. Woody scales from collapsing cones gather at the base of these trees.

The timber yielded by this species has a fine even texture that is pale cream to light or pinkish brown in hue, with a straight grain. Queensland kauri withstands some exposure. It dries quickly with little degrade but needs protection against blue stain, microscopic fungi that commonly infest the sapwood of trees.

Queensland kauri timber is commonly used for cabinetwork, turning, joinery and shelving. It is suitable for use in pattern making, lining, flooring, vats, boxes, battery separators and plywood. It is otherwise used for making furniture and violin bellies.

Shrinkage

Very Low Low Medium High Very High
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Tangential : Provides a simplified rating for tangential shrinkage. This is the measure of the percentage reduction in dimension from the unseasoned to 12% moisture content condition.

3.40%

Radial : Radial shrinkage is perpendicular to the growth rings. It is shrinkage in the direction towards the centre of the tree. Measurement is % value

3.20%

Unit Movement Tangential: This is the percentage of dimensional change for each 1% moisture content change between about 3% moisture content and the fibre saturation point for the particular species.

0.17%

Unit Movement Radial: This is the percentage of dimensional change for each 1% moisture content change between about 3% moisture content and the fibre saturation point for the particular species.

0.14%

Strength Group Strength groups are given for unseasoned (S1-S7) and seasoned (SD1-SD8) timber in accordance with AS 2878. S1 and SD1 yield the highest strength and stiffness whereas S7 and SD8 yield the lowest.

Very High

High

Reasonably High

Medium High

Medium

Reasonably Low

Low

Very Low

Unseasoned:

S1

S2

S3

S4

S5

S6

S7

S8

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Seasoned:

SD1

SD2

SD3

SD4

SD5

SD6

SD7

SD8

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Stress Grade A stress grade is defined in AS 1720 as the classification of timber for structural purposes by means of either visual or machine grading. The stress grade indicates the basic working stresses and stiffnesses to be used for structural design purposes. Measured in MPa.

Structural
No. 1
Structural
No. 2
Structural
No. 3
Structural
No. 4
Structural
No. 5

Unseasoned:

F7

F5

F4

Seasoned:

F8

F7

F5

F4

Density per Standard Seasoned density is based on moisture content of 12%. Unseasoned density is an approximation as it depends on the moisture content at the time of measurement. Measured kg/m3.

Seasoned:

470kg/m3

Unseasoned:

720kg/m3

Joint Group The joint group is a classification of the strength of a species in joint design. The values are from 1 (very high strength) to 6 (very low strength).

Very High

High

Reasonably High

Medium

Low

Very Low

Unseasoned:

J1

J2

J3

J4

J5

J6

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Seasoned:

JD1

JD2

JD3

JD4

JD5

JD6

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Colour The colour of seasoned heartwood can vary between species and often within a species. The information provided should be used as a general guide only. In most cases, the colour of sapwood is either a lighter shade of the heartwood or a white/cream colour.

  White, yellow, pale straw to light brown Pink to pink brown Light to dark red Brown, chocolate, mottled or streaky
   
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Mechanical Properties

Modulus of Rupture - Unseasoned: This property is a measure of maximum stress which timber can momentarily sustain when loaded slowly and continuously as a beam. Measured in MPa.

46

Modulus of Rupture - Seasoned: This property is a measure of maximum stress which timber can momentarily sustain when loaded slowly and continuously as a beam. Measured in MPa.

64

Modulus of Elasticity - Unseasoned: This property is of importance in determining the deflection of a beam under load — the greater the stiffness, the less the deflection. Measured in GPa.

6.8

Modulus of Elasticity - Seasoned: This property is of importance in determining the deflection of a beam under load — the greater the stiffness, the less the deflection. Measured in GPa.

7.8

Maximum Crushing Strength - Unseasoned:

Also referred to as compression strength. This property measures the ability of the timber to withstand loads applied on the end grain. Measured in MPa.

24

Maximum Crushing Strength - Seasoned: Also referred to as compression strength. This property measures the ability of the timber to withstand loads applied on the end grain. Measured in MPa.

39

Impact - Unseasoned: Provides the Izod value, which is the energy taken in joules (J) to fracture the timber.

5.5

Impact - Seasoned: Provides the Izod value, which is the energy taken in joules (J) to fracture the timber.

2.4

Toughness - Unseasoned: This is a measure of timber’s ability to resist shocks and blows, and is synonymous with impact strength. It is measured in Nm.

Toughness - Seasoned: This is a measure of timber’s ability to resist shocks and blows, and is synonymous with impact strength. It is measured in Nm.

Hardness - Unseasoned: Refers to the Janka hardness test and is a measure of timber’s resistance to indentation.

2.3

Hardness - Seasoned: Refers to the Janka hardness test and is a measure of timber’s resistance to indentation.

2.3

Durability

Low Moderate Reasonably High High
(0 - 5 yrs) (5 - 15 yrs) (15 - 25 yrs) (more than 25 yrs)

In-Ground: Durability is defined as the inherent resistance of a timber species to decay, or to insect or marine borer attack. All references to durability refer to the heartwood only. A scale of low to high (durability class 4 = low; 1 = high) has been adapted for above and in-ground durability.

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(0 - 7 yrs) (7 - 15 yrs) (15 - 40 yrs) (More than 40 yrs)

Above ground: Durability is defined as the inherent resistance of a timber species to decay, or to insect or marine borer attack. All references to durability refer to the heartwood only. A scale of low to high (durability class 4 = low; 1 = high) has been adapted for above and in-ground durability.

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(0 - 20 yrs, usually < 5) (21 - 40 yrs) (41 - 64 yrs) (More than 60 yrs)

Marine Borer Resistance: Indicates whether a species is resistant (R) or not resistant (NR) to marine borer attack.

Lyctid Borer Susceptibility: Indicates whether a species is susceptible (S) or not susceptible (NS) to lyctid borer attack.

Not Susceptible

Lyctid Borer Susceptibility - Other:

Termite Resistance: Indicates whether a species is resistant (R) or not resistant (NR) to termites.

Not Resistant

Fire Properties

Bushfire Resistance: Naturally bushfire-resisting timbers are those with inherent bushfire-resisting properties. Some species have been tested and a number are in the process of being tested and are measured by Bushfire Attack level (BAL).
BAL -12.5: Ember attack,
BAL – 19: Increasing levels of ember attack and burning debris ignited by windborne embers together with increasing heat flux between 12.5 and 19 kWm3,
BAL – 29: Increasing levels of ember attack and burning debris ignited by windborne embers together with increasing heat flux between 19 and 29 kWm3.

Not Tested
Appearance

The wood of the Queensland kauri is creamy-white. The surface is plain in appearance, and the timber has a fine grain and clear, even texture that is much darker than Hoop Pine. The shimmering ray flecks that occur on the face of quarter-cut timbers distinguish it from hoop and bunya pines, that produce a less startling figure. Heartwood and sapwood in of this species are difficult to distinguish. Finished timbers have a warm golden appearance, ideal for use in interiors.

Common Applications

The first European settlers fashioned Queensland kauri into kitchen sinks, breadboards, bench-tops and flooring. Today the timber is still used in a wide range of interior situations. Common applications include cabinetmaking, turnery and joinery. The durability and regular colours of the timber make it well suited to furniture design and indoor fittings such as shelves. Less sturdy grades of this timber can also be made into plywood, crates and boxes. Panels of Queensland kauri are used to line boat interiors. Luthiers also favour this timber for fashioning violin bellies and guitars because of the good resonating properties created by its regular grain.

Workability

Queensland kauri is generally easy to work except when compression wood is present. The timber stains and polishes well and can be finished to create a beautiful glossy surface. It can be glued successfully and rates as fair for steam bending. The heartwood of the Queensland kauri is not sufficiently durable for external use or for use in contact with the ground but accepts impregnation with preservatives. Because of the size of larger tree trunks (one to sometimes three metres in width) it was once possible to obtain fairly wide boards. When air-dried, the timber is fairly light, with an air-dried weight of 300-450 kilograms per cubic metre.

Origin of timber
QLD
Readily Available
QLD
Now a rare timber, the Queensland kauri is almost completely cut out and does not perform well in plantations. Other Agathis species are found in North Queensland and New Guinea. The New Zealand kauri is also almost unobtainable now.
Source of timber
Native Forest

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