Friends of the Earth believe the area could accommodate more than twice its current number of trees, and says the country's national parks are 'failing to step up' to the climate crisis.
The group revealed a report, supported the People's Postcode Lottery, that showed the Lake District could support more than 30% of woodland cover.
As it stands, trees make up just 12.5% of the National Park, lower than the Yorkshire city of Sheffield, which stands at 13.3%.
The environmental group say increasing woodland cover in the UK is vital for fighting the climate crisis.
Friends of the Earth campaigner, Danny Gross, said: “England’s national parks have not risen to the challenge of the climate and nature crisis. This isn’t even listed in their core purposes set out by the government.
“National parks cover roughly a tenth of England’s land and offer enormous opportunities for natural climate solutions, such as woodland creation and peatland restoration, which would also go a long way to support new wildlife.
“We have a chance to make England’s national parks trailblazers for natural climate solutions such as woodland and other precious habitats. It’s time for National Park Authorities, the government and landowners to step up and work together to fight the climate crisis.”
More on this as we get it.