With warming summer temperatures across Alaska, white spruce tree growth in Interior Alaska has declined to record low levels, while the same species in Western Alaska is growing better than ever measured before. According to researchers, 'The movement of an entire biome is often hypothesized in models of probable future climate, but the Alaska boreal forest is actually shifting today, and the process is well underway.'
http://www.sciencedaily.com/releases/2015/06/150611161304.htm