The Bob Brown Foundation is taking its legal battle to stop native forest logging in Tasmania to the High Court.
The conservation group had its Federal Court case dismissed on Wednesday but has vowed to fight on.
It had argued Tasmania's regional forestry agreement is invalid because it does not properly protect threatened native animals.
"The forest industry called for a wake after the Federal Court decision," foundation spokeswoman Jenny Weber said.
"Instead the Bob Brown Foundation held a celebratory launch of the next stage of its campaign including its move towards a High Court appeal."
Dr Brown held a town hall meeting in Hobart on Thursday and announced the decision to prepare a special leave application to the High Court.
Tasmania's Liberal government, Labor opposition, peak forestry body and state-owned forestry company Sustainable Timber Tasmania (STT) all support the Federal Court's ruling.
Resources Minister Guy Barnett said it was extremely disappointing High Court action was being pursued.
"The Federal Court was clear and it's time for the Bob Brown Foundation to respect the umpire's decision," he said.
"The government has always stated that we have full confidence in our regional forest agreement and our sustainable forest management practices.
"We will fight to protect Tasmanian businesses, jobs and communities."
Tasmania's forestry industry says it employs more than 5700 people, directly and indirectly.
The Federal Court judgment agreed with STT that there is a broader suite of environmental protections in force in Tasmania.
The foundation argues native forest logging has put the critically endangered swift parrot at further risk.
A recent study found there were fewer than 300 of the migratory birds remaining in Australia.
Dr Brown has twice been arrested in recent months at separate protests at logging coupes in the island state's northeast.