The wood for campfires is going to become more of a problem as more of us go camping and it gets more scarce with the rate of deforestation we have. Chainsaw or not, the only legal way to collect firewood is permission from a landholder. No State Government I've found legally allows collecting wood from the side of public roads and various councils enforce this to different degrees, ranging from ignoring it to fining you. The variance to this is PARs may have areas which the landholder allows collecting, usually to encourage you not to collect from the Nat Park those roads often lead to.
It's certainly noticeably harder to 'find' firewood these days where once it was very easy. One of the main reasons I go camping is to cook on a campfire, I reckon the food just tastes a lot better, plus I flamin hate flies and so winter camping is the norm.
I have an electric chainsaw, awesome tool, but it's still a tad noisy in a quiet campsite, so also carry a 500mm handsaw and that goes through quite thick wood fairly fast and quiet - this is for wood I transport in which are easier tied to the roof rack as longer logs.
I was in the NT last week where some trapped Euro tourists were cutting up Mulga around the campsite directly from living trees, apparently this is 'normal' in parts of Europe. We certainly don't want that!
One good thing in NT parks, is the common inverted pyramid steel fire pits which do seem to be quite frugal with wood use, so I'm going to get a Darche firepit as the design seems to be a good one.