Fires that have raged across a huge swathe of West Yorkshire moorland since Sunday are expected to cost the National Trust at least £500,000.
The charity, which owns Marsden Moor near Huddersfield, has appealed for donations to help fund its restoration.
It said £360,000 worth of recent restoration work and £80,000 worth of equipment was lost. It also spent £50,000 on hiring a helicopter.
Fire crews said earlier that all the fires were now out or under control.
The National Trust believes the costs are likely to rise by "several hundred thousand pounds" when the full extent of the destruction is calculated.
Rangers will assess on-the-ground damage once a satellite image is taken on Thursday to identify how much was burnt.
A trust spokesperson said: "It is currently estimated that a £360,000 investment... in restoring this special habitat has been lost."
The helicopter cost the charity £2,000 an hour and a specialist moorland vehicle and firefighting equipment worth £80,000 were also lost to the flames.
"In addition to this loss, more restoration work will be likely to cost several hundred thousand pounds," the trust added.
The Marsden fire is thought to have been started by a discarded barbeque at Easter Gate near the village of Marsden on Sunday.
It spread west to Saddleworth, Greater Manchester and at its height covered 15 sq km (6 sq miles).
Marsden Moor is a Site of Special Scientific Interest, a Special Protection Area and a Special Area of Conservation due to ground nesting birds and peat bog habitat.
A National Trust spokesman said a "significant amount" of restoration, funded by conservation body Moors for the Future, would have to be redone on the peat, essential for carbon storage, wildlife, flood management and archaeology.
Some parts may take months to recover, while other parts would take several years.
He added that birds may have flown away but their nests and eggs would have been destroyed and reptiles and small mammals like mountain hares may have been caught in the flames.
Two other blazes at Ilkley Moor are ending and being monitored by fire crews.
A man has been charged with arson in connection with one of those fires.