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?
They release their carbon as they rot or otherwise consumed. That's why the article talks about wood in cold streams, which rots very slowly.
In the long term they will decompose and return vast majority of its carbon back into atmosphere. Blame fungi and bacteria.