Comment by bluGill

Depends on how they burn and what forest we are talking about. A small intensity fire will leave many of the healthy trees alive while burning dead ones, and will turn some of the carbon into charcoal which is sequestered. A larger intensity fire will also kill healthy trees, and turns the carbon into CO2.

Many of the forests in North America need to burn every year in that low intensity fire. Their seeds won't even sprout until after a fire (when all the dead undergrowth has been burned away thus leaving the new sprout with sunlight). However this doesn't apply to all forests in North America, and I know even less about other countries.

Moral of the story: consult a forester who knows the local forest before talking about anything. In many places we have been badly mismanaging forests and there is no nice way out. We probably do need to burn down and start over with large parts of North America because of all the harm decades of "Smokey the bear" have done to our forests.