ah yes, very sensible. For those on dial-up:
While clean air is still important for our community, this winter it’s more important that you keep yourself warm.
If your home or heating has been earthquake-damaged, we understand that your first priority will be to stay warm and healthy.
We want to assure you that we will not take action if the earthquake means you need to use an old woodburner or open fire to stay warm this winter.
From above factsheet.
I guess that means the price of firewood has gone up due to increase demand.
Either way, it's quite clear that the cheapest way of heating is burning firewood -
by a long shot!