Taxes have no effect on 99% of people who cut, burn, or sell firewood.
Dont know anyone that pays taxes, or charges people taxes for selling.
As far as uncle sam come year end on that income.....I know most dont even mess with it. Say someone sells 10 cord a year for $1500. With so many things to write off, truck mileage, fuel, equipment, half a cell phone bill, etc etc......it would quickly show on paper as a loss or little to no profit. So since not really a net change either way on taxes....most just keep it simple and off-book.
So no point in complicating things with taxes or other fancy calculations to justify stuff.
Its as simple as this......my house needs a cord a month to keep warm. My house needs $160 paid to (pick your utility/fuel source) to keep warm.
So there is two options....Cut that cord and burn it. Or cut that cord, trade it for cash, and buy the heat of your choosing. Taxes dont come into play.