Trees trap carbon. When they die, trees release carbon. Unless you bury dead trees underground (e.g. as paper, furniture, etc., in deep landfills), in terms net amount of carbon capture, there's no difference between a massive forest fire, periodic controlled burns, decay, etc.
They differ in time cycles. Even a sequoia will eventually die and release its carbon back into the atmosphere.
There's this myth that forests somehow reduce carbon in the atmosphere. Left to themselves, they store carbon, but they can't capture carbon. They're carbon-neutral. If you cut them down and release the carbon, you have a one-time emission. If you plant new ones, you have a one-time carbon capture.
The only real net change to CO2 comes from:
1) Extracting dinosaur-era carbon, and releasing it.
2) How we handle our waste. Ironically, composting releases all the plant carbon eventually, while burying it underground stores some carbon away from the atmosphere.