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Timber Specification Guide www.timber.org.au

timber in environmentally sustainable development

Timber Specification Guidelines

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Timber in building

• Timber is a major building and preferable ESD material.

• It is renewable, drawn from trees whose growth and harvest is managed by forestry.

Sustainable forest management is necessary for building a sustainable society.



Timber’s resource takes time to grow

• Trees take at least 25-40 years to grow into a size usable for timber.

• Today’s designers live with forest management decisions made prior to 1960.

• Actions taken now will only have full effect after 2040.

Forest mosaic reserve areas between plantations



Timber’s changing properties

• Moves to sustainable forest management are changing the character of available timber:– Plantation pine is largely restricted to structural

uses, due to its softness and knots;– Mature native forest hardwood logs are large and

slowly grown but, with increasing conservation reserves, their supply is limited;

– Regrowth native forest hardwood logs are cut earlier and are making up more of the supply; while

– Plantation hardwood is still more quickly grown and cut. Its qualities as solid wood product are still to be established.



Changes in timber supply

• Due to these changes, the character and availability of timber is changing, including:– The availability of sizes; – Density & hardness; – Strength & durability;– Colour & grain; and– Feature.

Drying hardwood



Design implications of this change

• New aesthetic options; • A broader range of

assembled sections;• Different detailing; and• There is a need to use

material that underpins sustainable expansion of forests.

High feature flooring



A practitioner’s question

• What is the best source (native forest or plantation) and species of timber to use in applications?

Native regrowth forest



Specification guide

• Use timber when it is suitable for the project. – Timber has lower

embodied energy than most other material.

– It is usually locally produced in regional area.

– This generates employment and diverse economic activity, a vital part of ESD

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Specification guide

• Ideally, use certified local timber or recycled timber if available and fit for purpose. – If this is not available use

local timber before imports.

– The processes for local timber production can be verified.

– Recycled timber, by definition, has limited supply.

Regrowth forest



Specification guide

• Accept non-traditional species.– Minor species

harvested need to be used fully.

– Plantation species are selected for speed of growth, not for current market preference.

Minor species veneer



Specification guide

• Understand the supply and characteristics of local species.– Some species are not

available in quantities large enough for national markets but can service local projects.

– They should have economic uses.

Rare Huon pine in furniture



Specification guide

• Be aware that strength and stiffness relationships will change.– Faster grown

plantation hardwoods and softwoods are not going to be as strong as slower grown plantation or native forest material.

Hardwood and LVL framing



Specification guide

• Do not specify large sawn sizes if assembled sections are available. – Smaller logs cannot produce the same large

sawn sections as older, larger logs.



Specification guide

• Do not specify high appearance grades as a default. Use high feature material.– High feature material

from native forests should be used to its fullest potential.

– Plantation hardwoods may contain more high feature wood.

High feature veneer



Specification guide

• Be careful with expectations of colour.– In general, the colour

of regrowth and plantation timber is lighter than mature wood and also less consistent.

– Be prepared to sort, and develop uses for new colour groups.

Silver wattle veneer



Specification guide

• Select species for hard wearing applications carefully.– In general, regrowth

and plantation timber is softer than mature wood.

Theatre floor and seating



Specification guide

• Detail timber in external applications well and finish carefully.– Sustainability is not

served by letting good timber rot because of bad detailing.



Specification guide

• Use durable species externally or treat selectively. – The most durable

timber comes from mature material.

– Treatment increases the range of uses.

High durability posts and screens

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