Firewood?
Sustainable?
How about: *polluting*, *extremely unhealthy* the reason firewood is not used that much anymore is because of the problems it comes with. Wooden gas burner is not a solution, think about the environment as well, how many wild trees would be cut down just because people will try and sell it illegally once the prices sore. It's not an alternative, is not an option, we all need to learn about environment friendly options and at the end make things better not just for us but for our future generations as well.