I was curious haw this is actually measured, so to make it easier for others, LAI stands for "Leaf Area Index" [0], and is measured as "the one-sided green leaf area per unit ground surface area (LAI = leaf area / ground area, m2 / m2) in broadleaf canopies.[1] In conifers, three definitions for LAI have been used"
I'm a bit surprised to see the greening in the Rockies, and in North America in general given the devastation that the bark beetle has caused over the last 20 years. But it's nice to read that some trends are in the right direction.