Post-fire recovery is faster than expected in the forests of the western Cascades, SEFS-led study finds

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Photo by: Sofia Kruszka

New research published by the SEFS Harvey Lab looks at how forests west of the Cascade crest in Washington and northern Oregon are recovering from recent large and severe fires. The answer? Surprisingly fast, when compared to many interior dry forests elsewhere in the western US. When it comes to recovery, the age of the forest prior to the fire had an impact, with old-growth forests showing more abundant and diverse tree seedlings establishing after the fire compared to forests that were younger and simpler in structure before the fire. 

In other forests of western North America, post-fire tree regeneration has slowed or potentially stopped altogether in some cases due to increases in fire size, severity, or frequency in combination with warmer and drier post-fire conditions. However, even after recent large and severe fires, the burned forests on the west side of the Cascades are exhibiting rapid natural post-fire tree regeneration and forest recovery. 82% of stands where the fire was severe and killed all the pre-fire trees had post-fire regeneration rates that exceeded Washington state forest practice minimum density thresholds by 3-5 years post-fire, suggesting that, overall, naturally occurring tree regeneration is sufficient for meeting management objectives of forest recovery. Seedling density increased in areas with cooler and wetter conditions and with proximity to surviving live trees; but, surprisingly, tree seedlings were abundant at distances up to 400 meters from the nearest live tree. As lead author and PhD student Madison Laughlin put it “Seeing abundant post-fire tree seedlings at such far distances from live mature trees suggests we may be underestimating seed availability following severe fire in these forests. Seeds might be dispersing farther than previously thought, or some cones on trees that were killed by fire might persist, if not burned, and provide an on-site seed source. These are hypotheses we are currently testing in our ongoing research.”

Lead author and SEFS PhD student Madison Laughlin. Photo by: Brian Harvey

This research highlights the importance of old-growth forests and suggests that the complexity in older forests promotes forest resilience to severe, stand-replacing wildfires. Because these areas burn infrequently relative to other drier forest ecosystems in the western US, little research has been conducted on post-fire regeneration in the region. As warming continues due to climate change and wildfire potential increases in northwestern Cascadia, it will be critical to understand how forests are re-establishing with trees after severe fire. “Post-fire recovery of forest ecosystems is something that can play out over very long time scales, especially in forests that are characterized in part by infrequent and severe fires. These findings are encouraging signs for forest resilience to these kinds of fires in the northwestern Cascades, and our future re-measurements of these plots will help us track long-term recovery”, mentioned SEFS Professor Brian Harvey, senior author on the study. “We’re also measuring multiple complementary response variables in coordinated studies so we can track things like the entire post-fire plant community as well as the post-fire fuel profiles and potential for subsequent reburns in these areas. This collectively is helping us build understanding of how fire affects a wide diversity of ecosystem components, and with our partners, co-develop strategies for managing that diversity pre- and post-fire.” 

The study was published in the journal Forest Ecology and Management, led by SEFS PhD student Madison Laughlin with coauthors Jenna Morris, Liliana Rangel-Parra, and Brian Harvey from Professor Brian Harvey’s lab in SEFS, and Drs Dan Donato and Joshua Halofsky at the Washington Department of Natural Resources. It uncovers a critical piece in our understanding of forest resilience and managing post-fire landscapes. The findings suggest a high capacity for recovery from large and severe fires that are characteristic in forests west of the Cascades in Washington and northern Oregon—particularly in areas with old-growth forests.

This research was supported by a grant from the United States Geological Survey Northwest Climate Adaptation Science Center, the USDA Forest Service – PNW Research Station as part of the Westside Fire and Climate Adaptation Research Initiative, the Good Neighbor Authority between the USDA Forest Service and Washington Department of Natural Resources, the Jack Corkery and George Corkery Jr. Endowed Professorship in Forest Sciences, and support from Jerry Franklin.

As wildfire activity increases in forests, SEFS-led research helps predict wildfire severity based on fire size

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When wildfires cross a landscape, the severity of the burn isn’t uniform over the area impacted. Areas where most or all trees are killed by fire are considered “high severity burns.” The shape and size of high severity burned patches within fires play an important role in forest resilience and fire regimes, and have been difficult to predict.

person in a orange vest laughing in a forest
Michele Buonanduci and students from Prof Brian Harvey’s Lab conduct research of the Norse Fire from 2017 in the Snoqualmie National Forest

New research led by recent SEFS alumna Michele S. Buonanduci, a member of SEFS Associate Professor Brian Harvey’s lab, identifies a method to predict burn severity for future fires by looking at the relationship between fire size and patterns of burn severity. The researchers used data from over 1600 fires occurring in the Northwest US between 1985 and 2020 to see how relationships between fire size and severity vary across space and time, and found that the larger the fire, the higher the likelihood of large, contiguous, simple patches of high severity burned area. This relationship was consistent across the Northwest US and throughout the 35-year satellite record used in the study. Published in Ecology Letters, these findings provide a way to predict fire severity and impact based on projected fire sizes for near-term fires.

“It’s really difficult to plan for future fire activity if we don’t have a sense of what these fire severity patterns might look like,” said Buonanduci.

Given the complexity of the factors that influence fire severity, including topography, vegetation type, and weather, projecting future burn impacts is challenging. “A really wide range of severity levels and patterns are possible at any given landscape and just might depend on the weather at the time of burning,” said Buonanduci.

With collaborators from the Washington Department of Natural Resources, Buonanduci and her co-authors sought to anticipate the types of spatial patterns we might see in future fires, given projections for fire size.

Fire severity directly affects post-fire seed availability and dispersal, rates of forest regeneration, carbon uptake, and landscape change to non-forest. When you have large, contiguous high severity burn areas, forests are more likely to transition to non-forest vegetation as it’s more difficult for the remaining unburnt seed sources to reach the interior of the burn area than it would be in smaller, patchy burn areas.

“Those high severity patches are often where management intervention is most needed in terms of replanting with tree seedlings following fire. So having a sense of the range of ecological effects we might expect is going to be really important for forest managers working in a variety of contexts,” said Buonanduci.

aerial view of a burned forest
Students from Prof Brian Harvey’s Lab conduct research of the Norse Fire from 2017 in the Snoqualmie National Forest

Already, the results of this work are in use to better prepare land managers and communities for future fires. Buonanduci and her collaborators are using their findings to make projections for potential ecological effects of fire in western Washington and northwestern Oregon in the near future.

Co-authors on the study included Daniel Donato and Joshua Halofsky, SEFS affiliate assistant professors with the Washington State Department of Natural Resources, and SEFS alumna Maureen Kennedy, associate professor of quantitative wildfire ecology at the School of Interdisciplinary Arts and Sciences at UW Tacoma.

This work was funded by a US Geological Survey Northwest Climate Adaptation Science Center award and a Graduate Research Innovation award from the Joint Fire Science Program.

SEFS wildfire and forest management research highlighted in publications and presentations

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SEFS Professor Brian Harvey and students in his lab recently published papers on wildfire and forest management, including how fire potential and carbon storage after beetle outbreaks can be changed by forest management decades prior (Ecosystems), how forest resilience is affected by the combination of wildfire severity and post-fire climate conditions across the western US (Proceedings of the National Academy of Sciences), and how wildfire severity in areas experiencing more than one fire in recent decades are reshaping forest landscapes and forest resilience across the northwest US (Global Ecology and Biogeography). Harvey and students, as well as SEFS Assistant Professor Brittany Johnson, also presented at the Oregon Post-fire Research and Monitoring Symposium in February, including the following recorded talks:

RAPID Response: Brian Harvey to Study Re-Burned Yellowstone Forests

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by Karl Wirsing/SEFS

In 1988, wildfires burned about a third of Yellowstone National Park’s forests. Most of those wooded areas hadn’t burned in 100 to 300 years, largely within the average burn cycle for those forests, and they bounced back really well from the disturbance. But what happens when the next fire comes far sooner than the average? With shorter-interval burns and changing climate conditions, will the younger trees and forest be as resilient to a severe fire? Along with collaborators at the University of Wisconsin, Professor Brian Harvey will try to answer those questions, among others, this summer as part of a new National Science Foundation grant for Rapid Response Research (RAPID).

A lodgepole forest in Yellowstone that naturally reseeded after the 1988 fires.

RAPID grants are a special category for funding research that needs to be carried out immediately. They provide a one-year pulse of money for time-critical projects that can’t wait for the usual funding cycle. In this case, more than 10 thousand hectares of forest in Yellowstone did in fact re-burn last summer—only 28 years after the 1988 fires—so this summer will be the first and best opportunity to observe how these forests respond to the short-interval disturbance. “This grant provides an awesome opportunity to get there as soon as the forest is likely to show signs of resilience, or if it is not going to be as resilient,” says Brian. “This is the key time and place to be testing these questions.”

Natural disturbances, of course, are integral to forests worldwide, but conifer forests in western North America are facing warmer temperatures and larger, more severe wildfires than at any time in recorded history. Changing climates—with hotter, drier summers—are increasing disturbance frequency in some areas, and disrupting long-established patterns of forest regrowth and succession. In Yellowstone’s forests, the dominant species is lodgepole pine, which has closed, serotinous cones that release their seeds only in response to fire. Nearly all of the seedlings then establish one year after a fire; historically, they’ve then had many decades to grow and start producing cones (and seeds) of their own before the next burn. But instead of a fire interval of 150 to 300 years, these Yellowstone forests could start seeing new fires within a matter of a few decades. “Some systems are used short-interval fires,” says Brian. “But throughout much of Yellowstone, that’s a novel thing.”

The ecological consequences of these changing fire regimes are unclear and could be profound in the next century. The results of this study, in turn, could be widely relevant for understanding abrupt changes in forest ecosystems across the globe.

“This project is a unique opportunity to test what’s going on at the leading edge of climate change and changing fire regimes in these areas,” says Brian. “We’re really seeing the start of conditions in Yellowstone that may be heading outside the range we’ve seen in the paleo-ecological record. No matter what we find, it’s going to be extremely exciting, and very important. On one hand, these ecosystems can always surprise us in their resilience. On the other hand, as many times as we’ve been surprised by their resilience, we may be heading toward a state where things could be changing pretty rapidly.”

Similar to the sites Brian will be studying this summer, this lodgepole pine forest—originally burned in the 1988 fire—was re-burned in 2012 (with this photo taken in 2015).

Starting this July, Brian will head out to the burned sites in Yellowstone with his incoming master’s student, Saba Saberi, along with an undergrad field intern. They will meet up with a team from the University of Wisconsin, and together they’ll be investigating and measuring a number of factors for how the shortened fire interval is affecting the forest, including burn severity, post-fire tree seedling establishment and carbon storage.

A major component of this research, which Brian’s master’s student will be leading, involves studying how well satellites can measure burn severity in forests that are still very young since the last severe fire. “We have well-developed satellite indices to measure burn severity in forests, but most of these indices have really only been tested on older forests with much greater live biomass,” says Brian. “However, when fire burns through a dense stand of 25-year-old trees, we don’t know how accurately the satellite can detect burn severity. This is a big part of what Saba will be testing in her master’s research at SEFS. “Calibrating these satellite indices will allow us to investigate spatial patterns of burn severity over much broader scales, and gain insight into how fire regimes may be changing right before our eyes.”

The RAPID grant provides a total of $200,000 in funding, with just under $60,000 coming to Brian for his role in the project, and the rest supporting his collaborators at the University of Wisconsin.

Also joining the crew in the field will be a freelance writer from the New York Times to spend a weekend a write a store about the project. The Discovery Channel will be sending a team, as well, as part of documentary about the research on climate change and fire. Brian and his collaborators plan to produce a series of mini-documentaries (5-8 minutes in length), in English and Spanish, to explain effects of increased fire activity and climate warming on western forests to a wide audience.

It’s going to be a packed July for Brian and his partners, and we look forward to hearing reports from the field!

Photos © Brian Harvey.

New Faculty Intro: Brian Harvey

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by Karl Wirsing/SEFS

Brian Harvey might not be able to pinpoint the exact moment he knew he wanted to be a professor, but he can definitely recall a series of “pinch me” moments that gradually crystallized his dream—a dream he’s now realized, as he will be joining our faculty this spring as an assistant professor of forest ecosystem science and services!

Brian, who was born in Cleveland but spent most of his childhood in the San Francisco Bay Area, double-majored in geography and environmental studies as an undergrad at UC Santa Barbara. After he graduated, one of his first jobs was with an environmental consulting firm, where he was involved in a lot of remediation clean-up at industrial sites. “It was a really good experience in terms of working with all the different stakeholders in environment management,” he says, “from businesses and municipalities to state and federal governments.”

Brian with his wife Denisse Guerrero-Harvey and son Joaquin Guerrero-Harvey on a recent trip to New York City.
Brian with his wife Denisse Guerrero-Harvey and son Joaquin Guerrero-Harvey on a recent trip to New York City.

Still, though he found much of the work fairly interesting, Brian says the job mostly had the unintended effect of rekindling his interest in ecology and natural sciences—and therefore a desire to return to school.

So he then enrolled in a master’s program at San Francisco State University to study geography and natural resource management. “I went back to school to get back into ecology, and particularly forest ecology, and I did my thesis research on a post-fire study of the Point Reyes National Seashore.”

Resurveying an area that had burned in 1995, Brian was able to explore more than a decade of post-fire succession to see how the forest ecosystem had responded. “Those years at San Francisco State were when things really started to click for me,” he says. “I realized this was my dream job, to be able to combine research in forest ecology with teaching and mentoring.”

That revelation solidified his decision to continue on in graduate school for a Ph.D. Since he’d always been fascinated by the Yellowstone fires of 1988, he reached out to one of the pioneers of research in that area, Professor Monica Turner from the University of Wisconsin, and joined her lab to focus on forest disturbance ecology in the Northern Rockies. “That was sort of the next pinch-me-I’m-dreaming moment,” he says, “walking around in Yellowstone in the forests I’d seen as a kid go up in flames in 1988, and here I was getting to study this stuff for my Ph.D. It was unbelievable.”

Brian hiking to a research site with his youngest field assistant, his son Joaquin!
Brian hiking to a research site with his youngest field assistant, his son Joaquin!

While he was wrapping up his doctoral program in 2015—he had actually defended his dissertation in 2014 just before the birth of his son, who turned a year and half this August—he started looking for postdoc opportunities. He ended up applying to and getting selected for a prestigious Smith Conservation Research Fellowship, and he based his project at the University of Colorado Boulder.

Founded by Dr. David H. Smith, a pediatrician who developed a vaccine for childhood spinal meningitis and later became an active conservationist, Smith Fellowships support early-career scientists working in the field of conservation biology. The Society for Conservation Biology now runs the program, which brings in five fellows a year, provides funding for two years and allows them to design their own projects (SEFS Professor Josh Lawler was also a Smith Fellow from the class of 2004).

Professional training and development are also central elements of the program, as Smith Fellows attend three weeklong retreats a year. Traveling to different sites, they gain skills in everything from science communication and working with the media, to how to translate their research into successful environmental policy and management. “For me,” says Brian, “the Smith Fellows program has been a tremendous foundation for fulfilling my social contract as a scientist—making sure my research is not only broadening our understanding of the natural world, but also providing a solid foundation for informed decision-making.”

The core of the Smith Fellows program, of course, is the fellows’ proposed research project, and Brian has been looking at the phenomenon of subalpine fir decline in the Rocky Mountains. Largely overlooked since it never significantly factored into timber production, subalpine fir has suddenly gained prominence as some of its peers—especially lodgepole pine and spruce—have suffered extensively from bark beetle outbreaks. Mountain pine beetles and spruce beetles have killed trees across large tracts of forest, and Brian says a lot of research has identified subalpine fir has a critical stopgap species to keep habitat intact until the next generation of spruce and pine can establish. Yet now subalpine fir populations have also started to decline, so Brian is trying to figure out why that’s happening. “Resilience, or the capacity of forests to ‘bounce back’ after disturbance,” he says, “is critical for maintaining many of the ecosystem services we associate with forests—water supply, wildlife habitat, carbon storage and recreation opportunities.”

This research will keep Brian plenty busy through the fall and winter until he completes his fellowship, and then he’ll begin his move to Seattle. His official start date with SEFS is March 16, 2017, just in time for spring quarter—and he can’t wait to get here.

Brian taking a lunch break during fieldwork on a project examining post-fire tree regeneration in Grand Teton National Park in Wyoming.
Brian taking a lunch break during fieldwork on a project examining post-fire tree regeneration in Grand Teton National Park in Wyoming.

“As a forest ecologist, I can’t imagine a more exciting time to be in the Pacific Northwest,” he says. “You’ve got an enormous wealth of foundational forest ecology research from many of the folks at UW, and at the same time we’re starting to see the emergence of some really big changes in forests from wildfires and bark beetle outbreaks in the last several years.”

Brian sees a growing need to understand when, where and why these disturbances are happening, and to answer the critical question of how our forest ecosystems will respond. “A lot of my work focuses on understanding the mechanisms of resilience in these forests,” he says, “and then how processes play out across different spatial and temporal scales. Disturbances like fires and insect outbreaks are natural and important components of ‘normally’ functioning forests. At the same time, climate change and the associated steep increases in disturbance activity can trigger big changes in forests, setting different trajectories for decades to centuries.”

More broadly, Brian says he’s looking forward to connecting with graduate students and colleagues in the school and university, and collaborators and stakeholders across the Pacific Northwest. “The key theme in my research is looking at how forests change over space and time, and the role disturbance plays in those changes,” he says, “and I really like to use multiple approaches and tools to answer questions. That opens up a lot of opportunities to work with grad students who have a diverse skillset, and also to collaborate with folks across a broad spectrum of disciplines.”

We can’t wait to welcome Brian and his family to Seattle this spring, and to start harnessing his tremendous energy and ideas. “I absolutely love what I do,” he says, “and I’m excited to interact with folks who are as enthusiastic as I am!”

Photos © Brian Harvey.

Brian walking through a recently burned forest in western Wyoming where native fireweed (Chamerion angustifolium) has taken advantage of the space opened up from disturbance.
Brian walking through a recently burned forest in western Wyoming where native fireweed (Chamerion angustifolium) has taken advantage of the space opened up from disturbance.