Why are trees and farmland incompatible? Can cows and stuff not graze from trees or something? There are all kibds of trees, I'm sure there's something that doesn't drown everything around it in shade and grows low for grazing. And you can plant stuff far apart... I guess the trees they want are big chunky carbon sinks with no other purpose?
Bogs are excellent carbon sinks. Died plant matter turns into peat and in the long term to coal. The water isolates the carbon dioxide from getting out and is full of rare species that help taking care of it.
First? You need fallow land, in case of lower yields due to drought/etc, and this includes world wide issues such as war.
Second? Crop rotated, tiled (drained) land, and land with all the rocks, tree roots cleaned out is as gold.
Reverting emergency spare land back to trees is the very last thing anyone should want. Every other climate issue should be resolved first.
This is just plain dumb.