Treated wood interests, seeking to make green concerns a greater factor in consumers' deck-buying decisions, have begun publicizing an research paper they funded that found ACQ-treated wood has far better environmental characteristics over the life of the product than does wood-plastic composite decking.

The analysis by AquAeTer --an engineering firm specializing in energy, environmental, and ecological sustainability issues--and published in January in the Journal of Cleaner Production, a peer-reviewed online scientific journal, concluded that wood decking treated with ACQ (alkaline copper quaternary, a popular wood-treatment product) required less use of fossil fuel and had less impact on the environment than did a similar deck made of wood-plastic composite (WPC) material.

"Compared to an ACQ treated lumber deck of the same size, and using the assumptions of this LCA (Life Cycle Assessment), with the understanding that assumptions can vary, use of WPC results in approximately 14 times more fossil fuel use and results in emissions with potential to cause approximately three times more GHG (greenhouse gases), almost three times more water use, four times more acid rain, over two times more smog, approximately two times more ecological toxicity, and equal the eutrophication potential," AquAeTer's Christopher Bolin and Stephen Smith wrote.

The research was sponsored by the Treated Wood Council (TWC), an industry association for wood treaters and timber manufacturers located in the same office building in Washington as the American Forest & Paper Council. A spokeperson for TWC shared the results Tuesday in a briefing with ProSales' parent company, Hanley Wood.

TWC's promotion of the report comes just a few weeks after The Freedonia Group, a Cleveland-based market research firm, predicted that, when measured by lineal feet, wood's share of the decking market will decline from 86% in 2009 to 77% in 2014. Demand for wood will rise just 0.5% per year, going from 2.604 billion lineal feet in 2009 to 2.67 billion in 2014, Freedonia says. In contrast, wood-plastic composite and plastic lumber decking is expected to enjoy double-digit growth rates.

To date, the green aspects of wood vs. WPC haven't received much attention, but forest products companies appear to believe it's worth promoting. TWC spokesperson Kim Drew said that in eight consumer focus groups that wood interests have conducted recently, none of the focus group members brought up environmental issues as a concern when they were choosing products. But when the question of environmental sustainability was raised, they responded immediately, she said.

In doing its 25-page analysis, AquAeTer said it followed principles and guidance provided by groups such as the International Organization for Standardization, which produces ISO standards. The authors also indicated how they sought to create an apples-to-apples comparison of ACQ-treated wood and WPC despite dramatic differences within those two products. For instance, while WPC content can vary markedly, it based its conclusions on what it called a "typical" WPC product: 50% recycled wood flour, 25% post-consumer recycled high-density polyethylene (HDPE), and 25% virgin HDPE. The treated wood used was southern pine radius-edge decking.

AquAeTer based its conclusions on decks that covered 320 square feet and required approximately 1,000 board feet of decking material. Only the decking was examined; the green aspects of foundations were excluded, because they tend to be made from wood both in treated-wood and WPC decking projects.

The study also assumed that the deck would last 10 years, even though makers of WPC products give warranties for far longer than that. It assumed the use of some typical sealers on the treated-wood decking but didn't assess any impact from the use of cleaning substances on the WPC.

The study also noted that, in the greater scheme of things, decking isn't a big deal. "If an average family adds or replaces a deck surfaced with ACQ-treated lumber, their impact 'footprint' for [greenhouse gas] emissions, fossil fuel use, acidification, smog-forming potential, ecological toxicity, and eutrophication releases each is less than one-tenth of a percent of the family's annual impact," the authors wrote.