Interesting. I live a couple hours northeast of Anchorage, Alaska. It is a remote, mountainous area that is also in a rain shadow to some extent, thus fairly dry. I was having dinner recently with a local who has lived here his whole life of 60+ years. He said it is remarkable the increase in shrubs, trees, and general greening of the area since when he was a teenager. Places that were open tundra are now impassable. I'm sure some is increase in temperature, but CO2 could also be a factor.