But it's not like it's going to turn into some sort of desert, the area, after forest fires, will be replaced by another species that is presumably resistant to the fungus, and life moves on.
It just depends whether we value preserving diverse ecosystems, or if we're happy to spread species / diseases around the world and just see what survives. I'm not saying there's a fundamentally "right" answer, but I prefer diverse ecosystems to the point I think it's worth trying to intervene when possible.
Yes, Life (capital L) moves on, but perhaps not the kind of life that we'd prefer. We can just shrug and say, "Oh well" or we can take a moment to reflect on what, if anything, we might do to steer natural selection in directions we find more pleasant.