Three Decades On, Timber Durability R&D Keeps Australia Ahead

I read Jack Norton’s recent article on R&D funding and the need for sustained, long-term investment—particularly in durability assessments —with great interest.

As he highlighted, FWPA has played a crucial role by providing ongoing support for the National Centre for Timber Durability and Design Life (the Durability Centre) at UniSC since 2018.

As the current Director of the Durability Centre, I have seen firsthand how FWPA’s long-term commitment has enabled us to build and maintain the research foundations needed to support a durable and sustainable timber industry.

Thanks to this funding, the Centre was able to reinstate the decking trial referenced in Jack’s article, with further details shared in our latest newsletter. 

FWPA’s support has enabled us to establish new long-term field trials, revisit and assess older trials, and lead standards development with a long-term vision to ensure that timber performs as intended. Quite simply, this progress would not have been possible without FWPA’s commitment to long-term R&D investment.

Here’s a background and update on the 1996 Decking Trial

In late 1996, scientists from the Forest Research & Development Division of the State Forests of New South Wales initiated a long-term study to examine how preservative penetration in Pinus radiata heartwood influences timber performance in external, above-ground exposures.

At that time, the heartwood penetration requirements in the Australian Standard (AS 1604) were based largely on expert opinion rather than empirical evidence. This project was conceived to address that gap by generating real-world data to inform future standards and treatment practices.

The researchers evaluated two water-borne preservatives—chromated copper arsenate (CCA) and alkaline copper quaternary (ACQ)—alongside two light organic solvent preservatives—copper naphthenate and tributyl tin oxide—representing the major preservative systems used commercially in Australia in 1996.

Boards containing substantial heartwood were treated either to meet AS 1604 requirements or intentionally below compliance, then installed as decking at two exposure sites: Coopernook, NSW (moderate decay hazard) and Beerburrum, QLD (moderate to high decay hazard).

To further increase decay pressure, half of each deck was shaded to slow drying.

The study aimed to compare the durability of treated heartwood with untreated and fully treated sapwood and heartwood controls.

Early treatment assessments showed that the light organic solvent preservatives achieved very limited heartwood penetration, while the water-borne systems penetrated more effectively, though still not completely. Unfortunately, planned annual evaluations could not be continued due to limited resources.

The Beerburrum trial site was later destroyed by bushfire in 2000, but the Coopernook site survived—and was recently rediscovered. In early 2024, the remaining decking specimens were harvested, assessed, and relocated to the Queensland Department of Primary Industries site in Nambour for continued observation.

Nearly three decades after its establishment, this long-term trial offers invaluable insights into preservative performance and the challenges of treating heartwood—reminding us that meaningful research outcomes often unfold over decades, not years.

Our sincere gratitude goes to former Centre Director, Professor Jeffery Morrell, for bringing these samples to Queensland and to researchers, including Dave Gardner, who established this trial in the first place. I am pleased to share that the Durability Centre will now undertake annual assessments, and we look forward to sharing results with industry as they emerge.

According to Ian Blanden, FWPA’s Head of Research, Development and Extension, “without industry-wide, coordinated investment, Australia would lack the long-term datasets needed to inform standards, treatment requirements, and best practice.” FWPA’s sustained funding ensures Australia maintains critical national capability in wood durability science—an area where meaningful evidence must accumulate over decades, not grant cycles.