PORTLAND, Ore. (KOIN) — On a hillside in the Clatsop State Forest, small flags dot the hillside of a clear-cut area. It’s a site where the Oregon Department of Forestry planted new seedlings in early 2021 and it’s now serving as a source of data for which species fared best through the ice storm, heat dome and ensuing drought. 

Brad Catton, the reforestation unit forester for the Clatsop State Forest, is quick to note that this is by no means considered official research. Instead, he calls it “cowboy science.” 

“Because it isn’t science,” he said. “It’s not replicated anywhere. It gives us a quick snapshot and it’s what we need to see how things are doing.” 

In the Clatsop State Forest, the temperature climbed to about 108 degrees during the heat dome that impacted Oregon in late June. While this temperature isn’t as high as the 116 degrees the Portland metro area experienced, it was still a shock for the forest, which usually enjoys the cool, misty weather the Coast Range provides. 

The seedlings ODF is monitoring were planted between December 2020 and February 2021 in a 12,500 square foot area. They include five different tree species: Douglas fir, grand fir, noble fir, sitka spruce, western redcedar and western hemlock. 

In their first year in the ground, the baby trees saw both extremely cold and extremely hot temperatures. 

A Douglas fir seedling planted in the Clatsop State Forest has scorched branches after the June 2021 heat dome. Photo taken Dec. 1, 2021 (KOIN)

ODF started monthly progress inspections on the seedlings starting in May. At that time, the survival rates for each species were as follows: 

  • Douglas Fir 99% 
  • Grand Fir 100% 
  • Noble Fir 100% 
  • Sitka Spruce 100% 
  • Western Hemlock 96% 
  • Western Redcedar 100% 

By September, after the young trees endured the heat dome and an extremely dry summer, several more trees had died. ODF saw a particularly high mortality rate spike in the western hemlocks and grand firs. Here are the survival rates ODF reported in September: 

  • Douglas Fir 91% 
  • Grand Fir 56% 
  • Noble Fir 82% 
  • Sitka Spruce 100% 
  • Western Hemlock 41% 
  • Western Redcedar 80% 

While Catton doesn’t see this as official science, Jim Gersbach, a public information officer for the department of forestry, says it does serve as a source of data. 

Catton’s job is to replant parts of the forest. This data helps him know what grows best in what conditions. For example, he knows western hemlock prefer more shade, so he tries to plant them in places they will thrive. 

Although it’s hard to see, a dead western hemlock seedling stands next to the white flag in the Clatsop State Forest. The Oregon Department of Forestry said the seedling did not survive the heat dome and dry summer. Photo taken Dec. 1, 2021 (KOIN)

He said on average, western hemlock seedlings have a survival rate of about 59% in September. So, seeing the survival rate drop to 41% after an extremely dry year lets him know that they don’t grow well in those conditions. 

“I never want to force anything in anywhere. I’m always looking for what’s gonna grow the best and use that to our advantage,” Catton said. 

He said ODF has people working with assisted migration, which means shifting seed zones from the south farther north. He said he’s not familiar with the process, but he knows that as ODF sees the effects of climate change, there are people researching what plants will grow best if Oregon’s average temperature continues to increase. 

Larry O’Neill, Oregon state climatologist and associate professor at Oregon State University, said it’s wise for foresters and timber land owners to take into account that the baseline climate is changing. 

A western redcedar seedling planted in the Clatsop State Forest has scorched branches after the June 2021 heat dome. Photo taken Dec. 1, 2021 (KOIN)

“What that means in practice is that things that naturally grew here before or naturally were adapted here may not be so in the future,” he said. 

He said that in the future, the climate might not be hospitable to varieties of firs and cedars that have historically grown well in Oregon. With growing timber, a process that can last decades before harvest, he said it would be very wise to take the changing climate into account.

For now, Catton said he’s very sad to see such loss among some of the tree seedlings. But at the same time, he’s encouraged to see that a nearby stand of trees he planted three years ago came out of the summer mostly unscathed. Not a single tree appeared scorched by the heat dome. 

Still, he knows the full extent of damage might not be visible yet. He said while he’s glad most seedlings survived the heat, he wouldn’t go so far as to say they’re “bouncing back.” 

“I’m hoping that we’ve seen the extent of the damage and it won’t continue,” he said.