The specific area in question is a 100,000 km2 region known as the northwestern Eurasian tundra stretching from western Siberia to Finland. By using satellite imaging, field research, and interviews of indigenous reindeer herders, the researchers discovered that certain trees have grown over two meters in height over the last three to four decades across 8-15% of the studied area. Read the full report here.
Source: by George Dvorsky, i09.