Good question. I have never put any in my fireplace, and I have wondered if eucalyptus bark would make a tinder as good as my revered Utah juniper. Given their reputation, I will start with small logs. I don't believe they will burn for a long time..

The word I get from fire fighters who have been on a line with eucs is that they behave more like powder kegs than anything else, but I have actually not had that pleasure, either. Came close once with a campfire that got away in a eucalyptus grove, but we got it out before it torched any trees.