The Bob Brown Foundation's protests of harvesting specialty timbers at the Que River in the Tarkine "contradict the advice of the world's leading scientific experts on climate change", Britton Timbers says.
But Bob Brown Foundation campaign coordinator Scott Jordan said the company was "cherry picking" data and had used material from a report published in 2007.
A media release from Britton Timber on Monday quoted a statement from a 2007 report by the Intergovernmental Panel on Climate Change that said "a sustainable forest management strategy aimed at maintaining or increasing forest carbon stocks, while producing an annual sustained yield of timber, fibre or energy from the forest, will generate the largest sustained mitigation benefit".
Managing director Shawn Britton said that statement was reinforced by the report released by the IPCC in August 2019.
"Every tree harvested in Tasmania's native forests is regenerated and the sector is actively working to increase forest carbon stocks through increasing the plantation estate," he said.
But Mr Jordan said Britton Timber was "clearly trying to justify something that is completely contrary to what the report's main finding is".
"The overwhelming recommendation from the latest IPCC was we need to stop the logging of primary forests around the planet and we need to start the rapid restoration of degraded forests," Mr Jordan said.
Mr Britton said an engineered, plastic product imported from overseas was the "likely alternative" to the selective harvesting of specialty timbers under the Tasmanian Forest Agreement.
"To ship a plastic product from overseas instead of using a locally produced renewable natural material is madness, and hardly a good environmental outcome," he said.
Britton Timber also quoted a section from the 2019 IPCC report that said harvested wood products "can store carbon over the long-term and can substitute for emissions-intensive materials reducing emissions in other sectors".
Mr Britton said the Bob Brown Foundation was "not on the same page as global climate change experts".
"But if we are to take up the fight against climate change, we need to follow the best advice - and that is that timber is The Ultimate Renewable Building material. This is the scientific consensus," he said.