Called Bluegum in NZ. Family Myrtaceae. Hardwood origin Australia. Approx 500 species of eucalyptus in existence. All of these make extremely good firewood as the wood is so dense that is has prolonged burning time, and high heat out-put.
Eucalyptus, like elm, has high water content and needs long seasoning. There appear to be many different varieties that vary somewhat but in general, once seasoned these are hard woods that give good heat. They can have a slightly resinous, medicinal, although not unpleasant, smell due to the gums contained within, making them less than ideal for cooking. However, it can be an excellent heat source if well seasoned.