A new study has shown that trees that make up many of the forests in the eastern portion of the US are steadily migrating north and west, reports Phys.org.
If the trend continued, it could one day change the composition of western forests to look more like eastern forests, while some sections of eastern forests could shift to something else entirely.
The change seems to be due to a shift in climate as the southeast gets drier while the west gets gradually wetter. For instance, the range of the eastern white pine has moved over 80 miles west since the early 1980s.
Also, the scarlet oak has moved over 127 miles to the northwest from the Appalachians over the same time period and the tree is more common in the midwest.
"This analysis provides solid evidence that changes are occurring," wrote US forest chief Michael Dombeck. "It's critical that we not ignore what analyses like these and what science is telling us about what is happening in nature."
According to experts, subtle shifts in what grows at a forest's borders can mean big geographic changes over time.
According to researchers, as the climate warmed, the northern movement of vegetation into colder regions was to be expected, but the movement west was a bit of a surprise.
Songlin Fei, a forest ecologist at Purdue University in West Lafayette, Indiana, and his colleagues studied the shifting patterns of 86 types of trees using data collected by the US Forest Service's Forest Inventory and Analysis Program over two periods, from 1980 to 1995 and between 2013 and 2015 for all states.
They found more species were moving west than north, probably partly due to changes in precipitation patterns, the team reported on 17 May in Science Advances.
''That was a huge surprise for us,'' says Fei.