An Australian timber industry body is being investigated over claims it misled the public by asserting that buying wood products helped the fight against climate change.

The consumer watchdog has asked Forest & Wood Products Australia to respond to allegations it made two deceptive claims: that the CO2 stored in trees is locked up when they are logged and converted into wood products, and that forestry is one of Australia’s most greenhouse-friendly industries.

The “Wood. Naturally Better” advertisement campaign was based on variations on the slogan “It’s more than attractive furniture. It’s a helping hand in climate change.”

It prompted a complaint to the Australian Competition and Consumer Commission by the Wilderness Society. Forest campaigner Luke Chamberlain said the advertisements were “clear green washing”, and failed to reflect that logging old-growth forest resulted in larger greenhouse gas emissions than plantation harvesting.

“Eighty-five per cent of what comes out when native forests are logged ends up as woodchips, waste and sawdust and most of the carbon is lost during the forest burn and the creation of woodchips,” he said.

He said suggestions that forestry was a carbon-positive industry were “unsubstantiated and debatable”.

Forest & Wood Products Australia managing director Ric Sinclair said the complaint was baseless, citing a federal government report in 2005 that found forestry was Australia’s only carbon-positive industry.

He said the advertisements made no claims about emissions from forest waste. They aimed to improve the public’s poor understanding of the role timber products could play in storing carbon.

Last week the organisation published its own research that found timber in Australian houses stored about 100 million tonnes of carbon, adding about 2 million tonnes of CO2 equivalent each year as new houses are built.

“It is a statement of fact that wood products store carbon — half the dry weight of wood is carbon,” said Mr Sinclair.