Other than the Ents of Lord of the Rings fame, trees generally aren't known for their mobility. So news that some tree species may be headed north at an average clip of 62 miles (100 kilometers) a century may come as a surprise.
At that rate, stands of yellow birch in the U.S., for example, may move well north of the Canadian border by the early 2100s.
That's the finding of a new study led by the U.S. Forest Service, which concludes that a few dozen tree species in the eastern U.S. are moving north at an unexpected rate, likely due to global warming.
In a paper appearing this month in the journal Forest Ecology and Management, the study authors documented the northward march of 40 major tree species over 30 eastern states based on the distribution of seedlings versus mature trees.
Previous studies of plant migrations had been done using only computer simulations, or they focused on how some species are climbing up hills and mountains, said co-author Chris Oswalt, of the Forest Service's Southern Research Station in Knoxville, Tennessee.
By contrast, the new study looked at movement based on latitude, using a sampling of the forest service's most recent ground-based data.
The finding confirms a link between global warming and forest migration, said lead study author Chris Woodall, of the Forest Service's Northern Research Station in St. Paul, Minnesota.
"This is no longer conjecture," he said.
Umm. We kinda knew this. 10k years ago Canada was something of a waste land. The trees have been migrating north as a very brisk clip ever since the last glacial cycle ended. They were already moving north. The world was not is not and will not be in some sort of stable state, ecologically.
I need to get the paper, but it's probable that what they have done is tie the temperature changes at latitude to the flora. That would be a linkage that would be hard to ignore and "prove" that global warming was the causation. We'll see.
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