Aussiebushman, I think it depends on the individual tree. I certainly would not want to fell a 500 year old red gum for firewood if I could avoid it, but if it is plentiful and much younger trees are taken, then I see no real objection to taking a few. I always preferred White Box myself.
simonsays, I noted from your opening post that you considered Red Gum a particularly difficult tree to split. You need to get out to Oz and try some of the real tough Eucalypts - spiral growth is an understatement. Or, come and help me to split some old boles of olive trees. Chainsaws are a waste of fuel and sharpening files. A bloody big hammer and several steel wedges are the only way to end up with pieces small enough to put on the stove. The olive stumps are still easier than some Eucalypts.