Humans aren’t the only ones that got sunburned during the heat waves this summer — so did Oregon’s trees. The evidence of the “sun scald” can be seen all over the Coastal mountain range, but the long-term effects of this extreme heat remain to be seen.
You can see the damage for yourself when you look along the Coastal mountain range. If one is driving into Benton County from Lincoln County, you’ll see the red and burnt orange needles on the tops of Doug firs and ponderosa pines.
The damage isn’t confined to the Coastal range, but trees there seem to have been hurt the worst by the hot spell. Local foresters and ecology experts speculate that this is because those trees are less acclimated to hot weather.
“The average temperature over there is 10 to 15 degrees cooler than it is in Philomath,” said Steve Hiebert, longtime Lincoln County forester. “Those trees just weren’t accustomed to going up to 108, but that was the temp that day … It happened so quick and fast.”
Foresters like Hiebert think that this could have long-term effects on these trees’ growth, especially because June — the same month that saw record-breaking temperatures — is when these trees are in their natural growth cycles.
“The hot afternoon sun took all those needles and cooked them,” he said. “On the first day they stayed green and flipped over, then turned yellow and then about five days later they turned bright red and then they fall off shortly after. The outcome, I’m guessing, is going to be about a third less growth on the tree this year and the next few years.”
Even big timber outfits like Starker Forests are seeing the first kind of damage of this kind.
“This is kind of a new occurrence for us,” said company president Randy Hereford. “I’ve been with the company for 40 years and never seen anything like this as far as heat goes.”
He also said that the damage appears to be worse as you head into Lincoln County, as southern and western facing slopes were hit harder than the vast majority of forest lands in Benton County.
Hereford also said it seemed like the damage happened mostly to old growth trees, which tend to be more capable of bouncing back from extreme weather events.
“There’s lots of speculation as to why but we probably won’t fully know why we’re starting to see more red needles,” he said. “We’re seeing that mostly on the larger old growth trees.”
Scientists like Beverly Law, a professor emeritus of the Oregon State University College of Forestry, study ecophysiology, which directly analyzes the ways that organisms naturally react to their environments. She says that non-acclimatized trees being hit by the excessive heat may be one factor in the damage, but only time will tell how lasting of an impact this will have, or whether we’ll continue to see the same kinds of summers in the future.
“What can happen is some of them aren’t necessarily shut down permanently … some of those species will survive and start photosynthesis again,” Law said. “But we don’t really know what the long-term physiological effects will be. I’ve even seen ponderosa pine in the valley that were sun scorched … but then they had new needles growing on them in a couple few years.”
Climate change’s effect on extreme weather may worsen these physiological effects in the future, but scientists also can’t predict, specifically, which patches of forest will react in what ways.
“I think it’s like a ‘don’t panic yet (message),'” Law said. ‘But these extreme events, they’re hard to predict when they’ll happen. We know the weather conditions that set them up for it … (will) become more frequent in the future and you hope you don’t have this several years in a row.”