Tundra Shrubs Turn into Trees as Arctic Warms

Tundra is by definition a cold, treeless landscape. But scientists have found that in a part of the Eurasian Arctic, willow and alder shrubs, once stunted by harsh weather, have been growing upward to the height of trees in recent decades.

The reason for the change: the warming Arctic climate, they say.

Roughly 30 years ago, trees were nearly unknown there. Now, 10 percent to 15 percent of the land in the southern part of the northwestern Eurasian tundra, which stretches between Finland and western Siberia, is covered by new tree-size shrubs, which stand higher than 6.6 feet (2 meters), new research indicates.

"What we have found essentially is that the growth of these shrubs is really linked to temperatures," said study researcher Marc Macias-Fauria of Oxford University's Biodiversity Institute. "They are reacting to warming temperatures by growing more."