Is Wookie's rest on fire all the time?
How much time passes until you get to the Emerald Grove? Maybe one or two long rests if you tarry? At that time, you can already see it being on fire through the telescope. And then you may spend several months walking around and it is still on fire when you get there.
The only logical conclusion is that it is on fire by default and we had no particular reason to hurry when we got there.