In reply to RomTheBear:
I would never light fires wild camping in the hills.
However, as someone alluded to earlier, when canoeing I often have a wood fire. I use a firebox, raised off the ground, and carry my own fuel. Its a great way of having a fire without doing damage to the environment (I know this isn't strictly true, depending on where wood came from, and all the usual things about burning fossil fuels getting there, but neither is using gas/petrol).
On the shore, I have dug pits in gravel or sand and had them in that, using driftwood or carefully collected standing dead wood - in such a way that I wouldn't take all from one spot, and leaving masses for insect life. This works in places which are less visited. Where others, less careful, would see your activity, its best not to, as they may see it as carte blance to burn everything in sight.
For bothies, which I visit almost entirely in winter, I always have a fire - its part of the experience as well as heating. Only once have we burnt anything found locally, when some massive trees from a landslip had blocked the stream outside and needed clearing anyway. The rest of the time we carry all fuel - mostly coal but occasionally a nice log for visual effect!