The Paradox of Wildfire
The American West is burning. Can we find a way to prevent forest fires without actually making them worse?
The West is burning.
Wildfire has always been a fact of life in the dry, vast terrain west of the Rocky Mountains, but in recent decades, this intermittent phenomenon has become a routine disaster. The Eagle Creek Fire—sparked by a teenager setting off fireworks—raged through the Columbia Gorge in 2017, devastating 50,000 acres and raining ash down on Portland. Last year the Camp Fire decimated the California town of Paradise, killing 86 people, destroying thousands of structures, and wreaking damage estimated at $16 billion. This year the inferno returned with a vengeance: the powerful Diablo and Santa Ana winds fanned the explosive Kincade, Tick, Getty, and Easy wildfires in California, prompting massive evacuations and stretching responders to the breaking point. The risk of fire grew so intense that PG&E shut off power to millions of customers for days on end in an effort to stop downed transmission lines from sparking new ones. By November, the United States had seen over four million acres of forest succumb to a wall of flame.
The frightening intensity of the western wildfires come as no surprise to Prof. Aaron Ramirez [biology–environmental studies 2018–], who studies how climate change, drought, and fire interact to shape the ecology of our forests in the 21st century. For decades, he says, the federal government pursued a misguided policy of suppressing forest fires—a policy that has in some cases actually made them more intense.
The story of fire suppression in the United States began in the late 19th century, after massive forest fires polluted watersheds and threatened the supply of commercial timber. In response, the U.S. Forest Service decided to suppress any and all wildfires—the logic being that if you stop small fires, then larger fires will not occur.
In reality, Ramirez says, “fire is a natural part of these ecosystems, and suppressing it can have dire consequences for the health and resilience of the forest.” Historically, every so often, a lightning strike would start a fire that burns through the understory—the part of the forest closest to the ground—but would not kill the larger trees, which survive the blaze. This is especially true in the “dry forests” that thrive on the east side of the Cascade Mountains and in dry, lower elevations on the west side. Unfortunately, suppressing small fires in these forests creates a thick understory, choked with shrubs and small trees that are ready to burn. The thicker the understory, the more likely it is to fuel a devastating, high-intensity wildfire that destroys even the oldest and tallest trees.
This cycle of small fires that rejuvenate the forest and prevent catastrophic fires is not universal. Some forests, like the coastal rainforests in the rain-soaked mountains near the Pacific Ocean, may go for a thousand years without a natural fire. But when you take a forest in Eastern Oregon, which historically burns every seven to 14 years, combine it with a century of fire suppression, and subject it to a rapidly warming climate, you turn it into the arboreal equivalent of a time bomb.
Five Â鶹¹ú²úAV students with helmets are dangling from climbing ropes in a northern red oak that stands near the Hauser Library and Paradox Lost. These aren’t seniors trying to get their last P.E. credit in order to graduate; they’re biology majors learning how to climb trees to conduct canopy research—the technique of collecting data from the upper reaches of the forest.
Canopy research is a proud tradition in Â鶹¹ú²úAV’s biology department. Biologist Steve Sillett ’89 is a pioneer of the field and climbed Douglas-fir trees for his senior thesis with Prof. David Dalton [biology 1987–]. Some years later another student of Dalton’s, Eliza (Gould) Eisendrath ’98, climbed the old-growth Douglas-fir trees for her senior thesis.
For Ramirez, canopy research is a natural outgrowth of his interest in forest ecology. After earning a PhD from UC Berkeley in integrative biology in 2015, he worked as a postdoctoral researcher tracing the connection between climate change, drought, and fire in the Sierra Nevada forests, collaborating with the U.S. Geological Survey, the Nature Conservancy, and the Wildlife Conservation Society.
When he moved to Portland and saw firsthand the immensity of the trees that grow in the Pacific Northwest, he knew he was going to need some new techniques for getting the samples from these woody goliaths. “One walk through a forest dominated by Douglas-fir trees that are 250 feet tall will make you realize how special this place is,” he says. “And how techniques developed for other forest types won’t work!”
Prof. Ramirez and his students employ an approach to doing science known as “translational ecology.” Translational ecology, as he explains it, “is a process of doing, a science that incorporates the people who might one day use and benefit from your work.” For his research, that means working with natural-resource managers and others trying to conserve our forests.
Last year, for example, Indra Boving ’19 did her thesis in collaboration with The Nature Conservancy, which is working to manage forests in eastern Oregon by reintroducing more frequent fires as a way to prevent catastrophic fire and restore the natural resilience of these forests. Their technique is to thin the understory by chopping down the small trees and shrubs that cluster under the canopy of the “legacy trees”—the biggest and oldest trees. Partnering with the US Forest Service and local tribal communities, the agency then intentionally sets fire to the forest during the rainy season to clear out the understory and give the legacy trees some breathing room.
For her thesis, Indra looked at how these intentional fires affect the hydraulic function of trees—their ability to transfer water from their roots to nourish their leaves. She used samples from various plots of land—some had been thinned, some had been burned, and some had been left alone—to see which strategy yielded the healthiest and most resilient trees.
Â鶹¹ú²úAV biologists are also working on ways to predict the effects of wildfire without actually having to set one. To this end, Ramirez and his students built the ingenious Tree Toaster 9000, a recycled laboratory oven that they use to heat the branches of trees to simulate the effects of fire. Their experiments with the Tree Toaster allow them to better predict the kinds of impacts fire will have on the forest.
They also devised the BioBasecamp, a one-of-a-kind mobile laboratory that allows Â鶹¹ú²úAV students to do novel research in remote field sites. Starting with an Airstream Basecamp trailer, Ramirez installed solar panels and an impressive array of lithium-ion batteries to power all the lab equipment needed to perform crucial measurements—and even conduct experiments—in the field, without having to rush back to campus every time they need to peer through a microscope or measure the rate of water flow through a plant’s stems. “My hope for the BioBasecamp is that it allows students to take the lid off their creativity and design field-based projects that are difficult, if not impossible, for others to replicate,” he says.
In the darkness of an October Monday, hours before dawn, Ariel Patterson ’20 heads on a five-hour drive out of Portland to the Sycan Marsh Preserve in southern Oregon, about an hour northeast of Klamath Falls. “It’s so beautiful,” she says. “It is just miles and miles of forest, ponderosa pine, and lodgepole pine.”
Those trees are the reason she came to Sycan. Her thesis will build on Indra’s by looking at samples both from pine trees and from the surrounding soil, which contains rich communities of bacteria, fungi, and protozoans that maintain a complex symbiosis with the trees. Ariel uses a sterilized spoon to collect soil samples from various depths and distances from the base of the trees. Back in the lab, she will extract DNA from the samples to create a larger colony that she can study.
The tree samples are trickier: she climbs a ladder and collects branches from trees that have experienced burns, carefully selecting branches that sprout from the same height, measure 15 cm long, and are mostly straight, and places them in bags to ensure they don’t dry out. Later, back in the lab, she will subject them to different levels of simulated drought. These simulations will show how the hydraulic systems of the trees react to the drought stress that is becoming increasingly common as a result of climate change.
Ramirez’s passion for his research has inspired his students to undertake some incredible projects. Edward Zhu ’19 climbed more than 200 feet to the very tops of Douglas-fir trees to test a hypothesis that the tallest trees in a forest are the most vulnerable to climate change. If this is true, it may be harder for the giant trees that now define the Pacific Northwest to thrive in a warmer, drier future.
Edward looked at Douglas-fir trees in Powell Butte, a nature park in the Portland city limits. He compared trees of average height (roughly 100 feet tall) with the tallest trees (more than 200 feet tall) to see if either was more vulnerable to drought. This required climbing to the tops of the trees and cutting off branch segments to bring back to the lab and subject them to simulated drought conditions. What he found was that the tallest trees were indeed more sensitive to the effects of drought. This information was shared with Portland’s Parks and Recreation, and Ramirez and the students are currently working to figure out what it means for the future of Portland’s urban forest.
Maia Shideler ’20 is developing some methods using lichens as indicators of old-growth forest health as part of a larger experiment that is currently being done in the Ellsworth Creek Preserve in southwestern Washington by The Nature Conservancy to figure out how to take a forest that’s been subjected to severe logging and return some of the important qualities found in old-growth forests.
Purna Post-Leon ’20 and Claire Brase ’20 are studying how living close to humans changes the physiology of urban trees. Specifically, they are looking at how things like thethe urban heat-island and air pollution affect the water use of urban trees compared to more natural forests in the Sandy River Gorge.
Ramirez also teaches a field-based forest ecology and natural history course titled Leaves 2 Landscapes that takes students into the field to learn about the magnificent trees of the Pacific Northwest. The students also do independent translational ecology projects like planting blister-rust resistant sugar pine seedlings into the forests around Ashland. This semester, the students are developing their own science-based management prescription for a patch of forest managed by The Nature Conservancy. The prescription the students come up with will be implemented by the Conservancy—from the trees they mark for removal to the way they recommend the use of fire.
Looking to the future, Ramirez hopes that the environmental studies program at Â鶹¹ú²úAV will contribute to a deeper understanding of the complex cycles of drought and wildfire—and yield, in time, the seeds of change.
Alejandro Chávez lives in Berkeley, where he works remotely in tech and bikes around looking for cool beer and interesting food.
Tags: Â鶹¹ú²úAV, Diversity/Equity/Inclusion, Climate, Sustainability, Environmental, Professors, Research, Students, Thesis