Alder, American Red

American red alder grows on the west coast of the USA and is the most common commercial hardwood in that region. This attractive timber is used for furniture, interior mouldings, doors and turning and carving.

Other Names

Red Alder, Western Red Alder, Western Alder, Oregon Alder, Pacific Coast Alder

Botanical Name

Alnus rubra

Common Form
Sawn
Species Type
Hardwood
  • Overview

    • American red alder is the most common hardwood in the Pacific Northwest of the USA, and it the largest of the American alders. It is a fast-growing species and has nitrogen-fixing nodules on its roots that are formed as a result of a beneficial relationship with a species of bacteria. The distribution of red alder extends from southeast Alaska to central coastal California. While the species predominantly grows within 200 km of the Pacific coast, there is a small inland extension of red alder across northern Washington into northernmost Idaho.

    American red alder timber is almost white when freshly cut but rapidly changes to a light brown colour with a red or yellow tinge when it is exposed to air. Heartwood is formed only in very old trees and there is no visible boundary between heartwood and sapwood. The timber is of medium density and low bending strength, making it unsuitable for structural applications. However, it machines, polishes and turns well, making it an ideal timber for furniture, cabinetry and other interior applications.

    American red alder is available as both rough and dimension stock; veneer production is limited. While American red alder is readily available in the regions where it grows in the USA, its international availability is mixed.  The American Hardwood Export Council (AHEC) is working to increase the export of the timber into markets such as Australia.

    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.
    4.20%

    Radial : Radial shrinkage is perpendicular to the growth rings. It is shrinkage in the direction towards the centre of the tree. Measurement is % value
    2.40%

    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.
    0.26%

    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.
    0.15%

    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

    Seasoned:

    SD1

    SD2

    SD3

    SD4

    SD5

    SD6

    SD7

    SD8

    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:

    Seasoned:

    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:

    460kg/m3

    Unseasoned:

    730kg/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

    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.
    45

    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.
    68

    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.
    8.1

    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.
    9.5

    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.
    20.4

    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.
    40.1

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

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

    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.
    Low - up to 15 Nm

    Hardness - Unseasoned: Refers to the Janka hardness test and is a measure of timber’s resistance to indentation.
    2

    Hardness - Seasoned: Refers to the Janka hardness test and is a measure of timber’s resistance to indentation.
    2.6

    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.
    (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.
    (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.

    Lyctid Borer Susceptibility - Other:

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

    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

    American red alder timber is a moderately dense, reasonably straight grained and uniformly textured timber. When cut it is almost white in colour but changes rapidly to a light brown with a reddish or yellow tinge when exposed to air. Red alder can be sanded, painted or stained to produce a highly attractive finish.

    Common Applications

    American red alder is most commonly used for furniture, cabinets, interior mouldings, doors and joinery. Due to its excellent turning and carving properties, Red alder is used for novelties and kitchen utensils. It is also used in plywood and fibre-based products, such as tissues and writing paper. 

    Workability

    American red alder machines well and is an excellent timber for turning and polishing. It also nails, screws and glues well, making it ideal for furniture production. Red alder readily accepts paint and stains. Note that the grading rules are unique to this hardwood. The grades are: Superior (Select & Better), Cabinet (No.1 Common) and Frame (No.2 Common). When specifying red alder, it is recommended that you work closely with the supplier to determine the best grade for the intended application.

    Origin of timber
    North America
    Readily Available
    NSW
    American red alder is reasonably available in the regions of the Pacific Northwest USA where it grows. It is available in some international markets but limited in others. Check with local suppliers or the American Hardwood Export Council (AHEC) for availability of the timber in your area.
    Source of timber
    Native Forest

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