Exposed wood in the ground doesn't last long, if it does become part of the soil the carbon will escape into the atmosphere. The branches in cold climate might

Exposed wood in the ground doesn't last long, if it does become part of the soil the carbon will escape into the atmosphere. The branches in cold climate might take a decade to decompose, but those too will end up releasing carbon quite soon. It is true that nature takes care of it, so it's not a waste problem like plastic is, but carbon-wise this part of wood stops storing not long after the tree is cut.