University of Oregon Assistant Research Professor James Johnston said he was taught that when a large fire burned a moist, Western Cascade forest to the ground, and the area didn’t burn for hundreds of years afterward, that’s what created a complex, old-growth landscape.
Instead, his study found that ancient tree stumps in the Mount Hood and Willamette National Forests had burn scars from multiple fires over their long lives. It’s the first time tree-ring scars have been used to document fire records in the region.
Johnston said forests are complex because of—not in spite of—lower-severity wildfires which don’t kill many of the trees.
“This is really exciting research,” he told KLCC. “It was a bit in the nature of a scavenger hunt, excavating these giant, old-growth stumps with chainsaws. But it was also very frustrating, because I think that this research poses more questions than it answers.”
What kinds of questions?
“Everything,” said Johnston. “I think that we need to totally rethink what we think we know about old growth Douglas fir forests.”
Johnston said to figure out the best ways to foster healthy forests, relatively recent upheavals also need to be considered. Those include clearcuts, human infrastructure at the margins of forests, and hotter and drier weather patterns.
