I'd like to add to that, how much more soil carbon becomes present because of the litter being dropped by those trees?

How much more water is being stored in the ground because of an increase in soil carbon?

How much longer is the growing season extended by with additional water availability?

How does extending the growing season impact mineralization and root exudate formation?

How do these processes impact site specific net primary productivity? How does growing trees in a space impact our ability to grow trees in a space?

These questions are all individually difficult to answer empirically, but are compounded by the massive amount of geologic and climatic variation we see across the planet.