Dead trees keep surprisingly large amounts of carbon out of atmosphere

my old boss had an idea - "bury trees".

There's a bit of nuance to be filled out, like challenges of forest plantation monoculture and so on, but it always sounded quite practical to me. Iirc the idea derived from "coal".

Why do you have to bury them? Can’t you just let the logs sit on the forest floor?

Decomposition returns carbon dioxide to the air. Or worse, methane, if there isn't enough oxygen.

Don’t things decompose underground as well?