i zoomed into some land that i'm intimately familiar with in mississippi. it got the tree loss right (when some logging took place), but doesn't show the later reforesting.
Looking in the area of the map East Texas and eastward toward the east coast, there is a definite blue tinge showing indicating gains in that area. Using the slider to narrow the range makes it even more clear.
I wonder if this is gains from natural regrowth or reforestation efforts like you describe. I was pleasantly surprised to see any positive direction on the map as I have a seeminly pessimistic view on the situation.