Gum, Forest Red

Forest red gum is a versatile, dense and durable hardwood, with a light to dark red heartwood perfect for flooring, decking, construction and furniture making.

Other Names

Blue Gum (Qld), Red Irongum (Qld), Red Gum, Blakely's Red Gum, Eucalyptus umbellata, Eucalyptus vlakelyi, Eucalyptus blakelyi

Botanical Name

Eucalyptus tereticornis

Common Form
Sawn
Species Type
Hardwood
  • Overview

    • Forest red gum produces a reliable timber suited to a wide range of uses. The timber is highly durable with an extremely high density. It displays a tight interlocking grain alongside its lush red colour, making it excellent for applications where appearance and durability are important.

    As the name suggests, forest red gum is a medium to tall forest tree. Trees of this species grow to a height of 20 to 50 metres, with a girth of up to two metres. The trunk is straight and is usually unbranched for more than half the total height of the tree, with limbs that are more steeply inclined than other eucalypt species. The bark is shed in irregular sheets, resulting in a smooth trunk surface, coloured in patches of white, grey and blue. Rough dark grey to black dead bark is retained at the base of the stem.

     

    A versatile timber, forest red gum can be used in wharf and bridge construction, railway sleepers, cross-arms and mining timbers. It is suitable for all building members including posts and poles, framing, flooring, lining, decking and cladding. It is suitable for both indoor and outdoor furniture. As well as sawn and round applications, forest red gum is suitable for the manufacture of structural plywood.

     

    Eucalyptus tereticornis, the most commercially important of the two sub-species, spreads from coastal south-eastern Victoria to southern Papua New Guinea. E. blakelyi subsp. blakelyi is found from northern Victoria through New South Wales and into southern Queensland. Timber appearance and properties are identical for both species. E. tereticornis sapwood is not susceptible to lyctid borer attack, unlike E. blakelyi. This species is not susceptible to termites.

     

    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.
    8.60%

    Radial : Radial shrinkage is perpendicular to the growth rings. It is shrinkage in the direction towards the centre of the tree. Measurement is % value
    4.80%

    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.
    0.34%

    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.
    0.25%

    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:

    F17

    F14

    F11

    F8

    F7

    Seasoned:

    F22

    F17

    F14

    F11

    F8

    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:

    1000kg/m3

    Unseasoned:

    1170kg/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.
    85

    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.
    120

    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.
    12

    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.
    14

    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.
    44

    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.
    70

    Impact - Unseasoned: Provides the Izod value, which is the energy taken in joules (J) to fracture the timber.
    17

    Impact - Seasoned: Provides the Izod value, which is the energy taken in joules (J) to fracture the timber.
    15

    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.
    Medium - 15 - 24 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.
    Medium - 15 - 24 Nm

    Hardness - Unseasoned: Refers to the Janka hardness test and is a measure of timber’s resistance to indentation.
    8.6

    Hardness - Seasoned: Refers to the Janka hardness test and is a measure of timber’s resistance to indentation.
    11.3

    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.

    		 Check mark
    (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.

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    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.

    Resistant

    Fire Properties

    1 - non-combustible 2 - reasonably non-combustible 3 - slightly combustible 4 - combustible

    Fire Properties Group
    Number:

    Group Number - Other:
    3 if used on MDF or particleboard ≥12mm; veneer thickness 0.6-0.85mm

    Average Specific Extinction Area: This value is determined by the volume of smoke measured over the mass loss of the tested sample per test carried out in accordance with ‘Cone Calorimeter Test’ AS/NZS 3837. It is measured in units of m2/kg.
    <250

    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.
    BAL 12.5 and 19 – All AS3959 required applications
    Appearance

    The timber from forest red gum, as its common name indicates, is predominantly red. Heartwood ranges in colour from light to dark red. The sapwood is distinctly paler in colour, a grey or cream-red that is distinguishable from the heartwood. A moderately coarse grain that is uniform in texture complements these rich colours. Forest red gum is a timber that reliably displays interlocked grain.

    Common Applications

    Timbers of this species have a range of applications. As sawn and round timber, forest red gum is used in wharf and bridge construction, railway sleepers, cross arms, poles, piles (including wharf piles) and in mining timbers.

    For general construction purposes, sawn timber can be used in general house framing, cladding, fascia and barge boards. It is ideal for internal and external flooring, linings and joinery due to attractive colour and reliably interlocked grain. Its durability and strength make it excellent for fencing, landscaping, retaining walls. Decorative applications include use in outdoor furniture, turnery, joinery and structural plywood.

    Forest red gum is also suitable for some boatbuilding applications, including keels, framing and planking. The timber’s hardwearing characteristics make it useful for machinery bearings and underwater bearing applications of low stress. 

    Workability

    Forest red gum has class 1 durability for above and in-ground ­— the highest rating possible. Expect to have 25 years of service from forest red gum timber in-ground.

    The sapwood readily accepts preservative impregnation but penetration of heartwood is negligible using currently available commercial processes.Forest red gum does not require fire retardant treatment for use in construction in bush-fire prone areas.

    Timber of this species can be satisfactorily dried using conventional air and kiln seasoning methods, and is very hard. The interlocked grain often makes it difficult to dress cleanly on the radial surface.

    In spite of this hardness, no difficulty has been experienced with the use of standard fittings and fastenings. As with most high-density species, machining and surface preparation should be done immediately before gluing. However, this timber will readily accept paint, stain and polish. 

    Origin of timber
    NSW
    Readily Available
    NSW
    The Forest Red Gum grows naturally over a very broad range of latitudes and is unique among Eucalypts for this reason. The timber is therefore widely available.
    a kitchen with wooden cabinets and a countertop

    Joinery

    Timber joinery offers a classic, stylish touch to any interior or exterior space.
    a reception desk in a building

    Panelling, Interior

    Timber panelling creates interiors as warm as they are stylish. Commonly using an MDF or plywood substrate, internal timber paneling is natural and versatile and comes as either solid natural timber panels or as sheets of engineered wood products
    a wooden fenced hillside with plants and a fenced yard

    Retaining Walls (Landscaping)

    When it comes to retaining wall, landscape design and construction, timber is the natural choice. A material that is durable, sturdy and reliable, it has natural aesthetics that help it blend seamlessly with the outdoors. Careful consideration during the specification and design process will facilitate the creation of a long lasting, durable and beautiful timber retaining wall that will complement its surrounding landscape for years to come.
    a close-up of a building

    Cladding, External

    The natural appeal, versatility and strength of timber makes it the superior choice for external cladding. Through specification, planning, design and finishing processes, timber cladding not only creates a building of superior strength, acoustic and thermal performance but also creates a place of beauty, style and natural appeal.
    a room with tables and chairs

    Structural Timber Poles

    Timber poles are utilised in structural construction to provide support for gravity loads and resistance against lateral forces. Not only serving a structural function, timber poles provide many aesthetic benefits, with their use in construction often complementing architectural designs aimed at harmonisation with the natural environment.
    a room with benches and paintings on the wall

    Flooring

    The warmth, strength and natural beauty of timber flooring is enduringly popular in a wide variety of domestic, commercial and industrial applications.

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