With a wildfire there's no point in fighting 99% of it - you fight the edges that are near people/property, try to contain it, and wait for rain and for it to run out of fuel. So of a 1000 sq km fire it may only be a few dozen linear kilometers that are being actively fought.
From a forestry management perspective, you don't want the forest to live forever, and trying to prevent old, dead trees from burning is a nightmare. Let the fire burn, protect the property, and the forest will reseed itself during the fire.
