Longer growing seasons enabling seedlings to take hold
FRISCO — As the Earth steadily warms, snowpacks are dwindling, especially in spring, leading to a longer growing season that enables trees to replace grasses and wildflowers by taking root in high mountain meadows.
A new study by Oregon State University researchers suggests the tree invasion has been accelerating the past few decades, at least in the Pacific Northwest, where the scientists reported the results of a long-term monitoring project in Jefferson Park, a subalpine meadow complex in the central Oregon Cascade Range, where tree occupation rose from 8 percent in 1950 to 35 percent in 2007.
“We worry a lot about the loss of old-growth forests, but have overlooked declines in our meadows, which are also areas of conservation concern,” said Harold Zald, a research associate in the College of Forestry at Oregon State University and lead author of this study. Continue reading “Global warming: Trees are invading mountain meadows”