Only you can prevent Endor fires!
Smokey the Bear is an American National Park icon and he has a message for everyone: “Only YOU can prevent forest fires!” Somebody should have mentioned that to the Rebels before they blew up the Imperial bunker, because — and I’m not sure if you noticed this or not in Return of the Jedi — the explosion is near nuclear proportions! The forest fires will rage for weeks, maybe months, considering this is a forest moon.
So, even though the radiation fallout from the exploding Death Star was going to kill them anyway, the Ewoks could also burn to death. Not great to be an Ewok…