Wood fires aren't great if you're growing and cutting down the trees but if he's burning wood from trees that have fallen naturally and would otherwise rot it's

Wood fires aren't great if you're growing and cutting down the trees but if he's burning wood from trees that have fallen naturally and would otherwise rot it's a lot better - the rotting itself releases CO2 at a similar level so you're not increasing the overall CO2 emissions, just changing how it comes about. Obviously trees that fall naturally aren't sustainable on a large scale but for an individual it's feasible.