Environmental groups have attacked a decision to increase woodchip production from Western Australia’s Karri forests.

Woodchips are sold as a by-product of high grade Karri logging and the state government is increasing the annual harvest allowance under its forest management plan by 37%.

The environment minister Bill Marmion says the new allowance is consistent with the availability of karri and will allow for improved forest management.

He says there has been a higher level of low grade timber than expected.

“Unless we allowed them to process the higher volume, it’d go to waste,” he said.

WA Forest Alliance spokesperson Jess Beckerling disagrees.

“The karri forests are far better left alone to store carbon, provide habitat for our unique wildlife in Western Australia and to recover from the logging that’s occurred in them,” she said.

She says Karri forests are producing less high grade timber than before so the trees should just be left to grow.

“The Karri regeneration is struggling, it’s really struggling,” she said.

Mr Marmion says, however, the increase will ensure better long term forest management.