research « College of Forestry

OSU Research Forests student worker Devon Swank recently met with forest ecosystems and society Ph.D. student Rachel Zitomer to learn about some of her research on bumble bee nutritional ecology in the McDonald and Dunn Forests. Rachel is a Ph.D. student within Dr. Jim Rivers’ Forest Animal Ecology lab.

Rachel’s doctoral research examines native bee health in early successional conifer forests. Specifically, Rachel explores how characteristics of timber forest landscapes impact bumble bee health and reproduction across time. “Essentially, this research aims to provide forest managers with information about what flower species are most important for bees and what time of year the flowers are being used”, says Rachel. This information is beneficial when planning for vegetation control and restoration plantings, and can make forest management decisions more bumble bee friendly.

Why do we need pollinators?

Pollinators like bumble bees are responsible for fertilizing most of the world’s flowering plants and play a crucial role in our ecosystems. Pollinators influence our food and agricultural industry, too: wild insect pollinators are estimated to contribute about three billion dollars to the U.S. agriculture industry through pollination every year.

Unfortunately some species of bumble bee, such as the western bumble bee (Bombus occidentalis), once a common species of bumble bee in Oregon, have experienced rapid population decline over the last few decades. These declines can be attributed to a variety of factors, including climate change, pathogens, and impacts from human uses. These varied factors may contribute to bumble bee nutritional stress and decline.

Bumble bee nutritional needs

When bumble bees forage, they collect pollen and nectar by traveling from flower to flower. Nectar provides carbohydrates which fuels movement in adults and provides essential energy. Pollen provides lipids and proteins which are vital to reproduction and the development of young bees.

*Male Bombus flavifrons nectaring on bull thistle (photo by R. Zitomer)*

Pollinators in conifer forests

Generally, bees prefer open habitats with warm ambient temperatures, nesting sites and flowering plants. Given these habitat requirements, research on bees in conifer forests is lacking. This gap in research may be attributed to the fact that conifer forests are typically assumed to be shaded environments with cooler temperatures and few flowering plants. This assumption is certainly accurate for closed-canopy forests. However, there is growing evidence suggesting that bees can be quite abundant in early seral conifer forests.

Early seral forests contain key characteristics that are beneficial for bees, including low canopy cover, warmer understory temperatures, and higher flower counts. Additionally, early seral forests may provide abundant nesting opportunities, but further research is needed in this area.

Ultimately, understanding seasonal changes in bee foraging preferences and nutritional intake in actively managed early seral settings will help land managers better identify what species are most beneficial to bumble bees after a harvest and across planting seasons.

Field sites and data collection

Rachel identified twenty early seral stands in the McDonald and Dunn Forests. These were sites that had been harvested within the last 10 years. At these locations, she measured three aspects of bumble bee foraging across the foraging season (May through August) in 2020 and 2021: 1) The floral preferences of foraging bumble bees; 2) The number of flower species visited by individual bumble bees and by all bumble bees collectively; and 3) The macronutrient ratios (e.g., protein to lipid concentration) of bumble bee-collected pollen.

“We are interested in examining bumble bee nutritional ecology across time because the diversity and density of floral resources changes substantially throughout the foraging season. These seasonal shifts could affect bumble bee foraging behavior and nutrient intake” says Rachel.

Map of pollinator research field sites in the McDonald and Dunn Forests. Map provided by R. Zitomer.

What’s next?

Rachel is now analyzing the results and we are eager to write a follow up article with some of the findings! This work is of high importance to the OSU Research Forests and to other forestland managers across the state hoping to conserve and promote habitat and resources for our native bees.

This article originally appeared in the OSU Research Forests newsletter. Thanks to the OSU Research Forests and Devon Swank, OSU Research Forest student communications and outreach assistant, for allowing us to reprint this article. Devon is a senior in the College of Forestry studying natural resource management. Get updates from the OSU Research Forests.

Ashley D’Antonio is an Associate Professor of Nature-Based Recreation Management. She does research focused on recreation ecology and outdoor recreation management, and teaches undergraduate courses on similar topics. This summer, she continued work on an ongoing research project just outside Falls City, Oregon on land managed by the Oregon Department of Forestry (ODF) called Black Rock Mountain Biking Area.

Describe an average day
Most days we would pick up our field gear at Richardson Hall around 9 am and then drive out to the trailhead (about 50 minutes away). On a typical day, we’d do one of two types of data collection. Some days we head into the trail system to download data from automatic trail counters that we’ve installed throughout the mountain biking trail system. These automatic counters estimate how many people are using the trails. We also are conducting visitor surveys as people wrap up their visit – these surveys help us understand who is using Black Rock Mountain Biking Area, why they are using the area, and what changes they may like to see to the area. When doing surveys, we spend quite a bit of time waiting at the trailhead for folks to finish mountain biking, it can get really busy, but it’s also good to have a book to read during downtime between visitors.

Describe a non-average day
Part of this project is also to help ODF think about how they might monitor recreation use at other recreation sites they manage. So, I did have one non-average day when our fieldwork was a guided tour of the Tillamook State Forest. We were able to see the varied types of recreation offered by ODF including OHV use, hiking trails, and campgrounds. It was great to meet with ODF managers and spend time with my project collaborators from the University of Washington in the field.

Describe your field crew/other entities you worked with
This project would not be possible without the amazing field crew of students that have been helping! Skyler Cristelli, a Natural Resources student in the College of Forestry, has been leading the fieldwork on this project. Last winter and spring terms, Opal Christian – a recent TRAL grad – helped Skye will all of the data collection until she graduated. And then this summer, a new Masters of Natural Resources student, Jon Anderegg, joined the project. We’re out there working at least 4 days a month for an entire year, so student help has been essential. We are also collaborating with Spencer Wood and Sama Winder at the University of Washington’s Outdoor Recreation and Data Lab. They are using remote methods (social media and a chatbot) to monitor use at Black Rock Mountain Biking Area and we’ll be comparing our data to see which approaches will be best for ODF broadly.

What happens now with this research?
We’re still collecting data on this project for a few more months. After that, we’ll be collaborating with the University of Washington to write-up a project report for ODF. We hope the work helps them to better understand and manage use at Black Rock Mountain Biking Area. And also, the overall project will help inform ODF about approaches for monitoring recreation use at other recreation destinations that they manage.

Anything else you want us to know?
I don’t mountain bike (I am too risk adverse, ha!), but Black Rock Mountain Biking Area is an amazing location! The folks that ride there are so nice and friendly, and the trail system is pretty unique. I’ve had some of my most positive experience surveying folks about outdoor recreation at this site this past summer.

What I did this summer is a profile series of students, faculty and staff in the College of Forestry. Did you have a great job, vacation, or field research experience? Contact CoFThisWeek@oregonstate.edu and we will be in touch!

The TallWood Design Institute, housed at the OSU College of Forestry, is a founding member of The Oregon Mass Timber Coalition (OMTC)—a partnership working to create a holistic vision for solving some of Oregon’s most pressing issues in forest health, affordable/sustainable housing and workforce development.

In September 2022, the White House announced the coalition will receive $41.4 million in funding from the U.S Economic Development Build Back Better Regional Challenge to invest in the future of Oregon’s forests, mass timber industry and sustainable built environment through restoration initiatives, local manufacturing infrastructure, research and development and affordable modular housing production.

Of the $41.4 million award, approximately $24.5M will flow to Oregon State University and University of Oregon to fund mass timber research and development, smart forestry initiatives and two new research facilities: the Oregon Acoustic Research Lab at University of Oregon, and the Oregon Fire Testing Facility at Oregon State. Oregon’s University Innovation Research Fund will contribute an additional $6M to the effort.

“Research and development has served as a critical tool in advancing timber in the built environment,” said Iain Macdonald, Director of Tallwood Design Institute. “The Oregon fire testing facility at Oregon State will help bolster the university and the region as a mass timber research and development hub.”

Forest engineering and resources management professor Woodam Chung is leading some of the research and development efforts. His smart forestry initiative aims to create a more resilient Oregon using data-driven forest restoration treatments with an emphasis on removing small diameter logs to increase fire resiliency, innovative technologies to increase forest workers’ health and safety, and workforce education to transform rural economies. According to Chung, forest restoration faces challenges from labor shortage, dangerous and outdated forest practices, and low-value wood.

“Innovative technology solutions are key to successful forest restoration projects to improve the resiliency of forests and forest-dependent rural communities,” said Chung. “ High quality forest inventory and wood procurement mapping will facilitate data-driven decision making for maximum benefits of forest restoration. Value-added wood products and improved efficiency of wood supply will enhance the economic viability of forest restoration projects. And finally innovative education, well-paying modern job opportunities and improved logging technology will support local forest industries, rural communities and improve forest workers’ health and safety.”

Tallwood Design Institute will also utilize the funds to help manufacturers and designers fabricate, prototype and test mass timber housing solutions with an emphasis on design that uses small-diameter logs. Mass timber is a sustainable substitute for carbon intensive materials and building systems and is an affordable, quality and energy efficient option for modular and affordable housing. Read more about the project!

This story is part of the College of Forestry 2022 Fall Update – learn more about our research, new hires, and outreach.

The College of Forestry at Oregon State University is leading a three-year $4 million-dollar project, with the US Forest Service, Washington State University, Montana State University, and multiple other partners from academia, government, tribes, and community organizations, to develop critical knowledge and increased capacity to inform policy and management decisions for resilient forested watersheds and downstream communities to ensure the protection and distribution of safe drinking water.

When watersheds burn, there is increased potential for floods, erosion, mass movements, and introduction of contaminants to streams and rivers. This issue is critical, because wildfire prone forested watersheds supply water to between 60–70 percent of the US population. These hazards and contaminants can catastrophically impact downstream community infrastructure, drinking water treatment, public health, and aquatic ecosystem health.

“The effects from wildfires on water supplies can persist for decades, resulting in hidden costs to communities that have been estimated to be 30-times greater than the costs of wildfire suppression,” said College of Forestry Professor Kevin Bladon, forest disturbance hydrologist and lead investigator on the project. “Additionally, many communities are unknowingly vulnerable because of inadequate drinking water treatment plant processes and preparedness to treat climate change and wildfire-associated changes in water quantity or quality.”

The funding for this work was part of the 2022 U.S. federal budget and was put forward by Oregon state Senator Jeff Merkley as a priority issue. The research will provide decision makers with information and tools critical to improve their understanding of wildfire impacts in forested watersheds, the opportunities for active forest management to mitigate risks, and to identify communities at greatest risk for impeded distribution of safe drinking water.

“Safe drinking water is one of society’s most basic needs,” said Bladon. “Preventing or mitigating the potentially devastating and long-term impacts of wildfire and climate change on essential clean water supplies in downstream communities is crucial to increase community preparedness, ensure healthy communities and reduce long-term aquatic impacts and financial costs.”

This story is part of the College of Forestry 2022 Fall Update – learn more about our research, new hires, and outreach.

The U.S. Economic Development Administration (EDA) has awarded the Oregon Mass Timber Coalition (OMTC) $41.4 million to develop and expand Oregon’s emerging mass timber industry. The award was announced September 2, 2022, and addresses three significant issues across Oregon:

A worsening housing crisis
Increasing threats of wildfires
The need to create good-paying jobs in communities recovering from the pandemic

The grant will support university research involving the use of mass timber in housing; spur development of a factory by the Port of Portland to produce mass timber housing; fund forest restoration projects in the Willamette National Forest; jump-start public-private partnerships to grow employment in the creation and use of mass timber in housing; and support efforts to modernize building codes in Oregon communities impacted by recent wildfires to enable recovery efforts using mass timber products in housing.

The EDA’s $1 billion Build Back Better Regional Challenge is a signature initiative of the Biden Administration’s American Rescue Plan program. It aims to boost economic recovery from the pandemic and rebuild American communities, including those grappling with decades of disinvestment. The OMTC is one of 21 coalitions selected from a nationwide pool of 529 applicants to receive funding through the EDA’s Build Back Better Regional Challenge.

“I’d like to thank the Biden-Harris Administration and the U.S. Economic Development Administration for recognizing the incredible work being done by the Oregon Mass Timber Coalition,” said Governor Kate Brown. “From the new roof for the Portland International Airport to housing materials, Oregon’s mass timber industry is at the cutting edge of sustainability and economic opportunity––helping to address the climate and housing crises while enhancing forest resiliency and creating jobs for people from rural communities, people with low incomes, and people of color.”

“This is a transformational moment for Oregon,” said Port of Portland Executive Director Curtis Robinhold. “The project will create rural and urban jobs with products grown and manufactured right here in Oregon. The innovations will enable production of high-quality building products from low-quality wood. This will increase housing, provide jobs and promote forest health. That means more homes at lower costs, new workforce opportunities and more climate-resilient communities. We are grateful to Oregon’s entire Congressional delegation for their support of the OMTC project and our vision for growing Oregon’s mass timber industry.”

The Oregon Mass Timber Coalition is a partnership between the Port of Portland, Business Oregon, Oregon Department of Forestry, the Department of Land Conservation and Development and the TallWood Design Institute (a collaboration between the University of Oregon and Oregon State University).

Mass timber is an advanced engineered wood product that is an alternative to the use of concrete and steel in multi-story buildings. “Already a global leader in mass timber, the Northwest is poised to bring mass timber forward as a housing solution,” said Iain Macdonald, director of the TallWood Design Institute. “Mass timber allows for rapid construction using sustainable, locally sourced, low-carbon wood products.”

President Biden visited Portland International Airport in April as part of a national infrastructure tour. He met with members of the OMTC and observed the use of locally sourced mass timber construction in PDX’s new nine-acre mass timber roof and learned how mass timber can be used in housing.

The $41.4 million federal investment will jump start development of mass timber housing products. The Port of Portland will use the funding for site improvements that will lead to constructing a factory at Terminal 2 in Northwest Portland to build mass timber housing.

“This award recognizes Oregon’s leadership in mass timber design, engineering and construction, supported by the TallWood Design Institute’s research and development work” said Judith Sheine, professor of architecture at University of Oregon. “The EDA grant will fund lab facilities and additional research and development critical to the continued growth of the mass timber sector and its expansion into the affordable housing market.”

The Build Back Better funding will support a comprehensive strategy for expanding the mass timber housing market, including:

Mass timber research and innovation: The award will accelerate the mass timber research and development efforts by constructing an acoustic testing laboratory at University of Oregon and a fire testing facility at Oregon State University. In addition, the award advances applied research at UO and OSU by testing mass timber housing prototypes for structural, seismic, durability and energy performance.
Terminal 2 Mass Timber Innovation Hub: Federal investment will offset the costs of site development for a mass timber modular home factory, the University of Oregon’s acoustics research lab and a fabrication facility at the Port of Portland’s Terminal 2. Planning for site improvements at T2 will begin immediately, with construction of the lab and site work expected to begin in 2024.
Public-Private Partnerships will be developed to produce mass timber homes at a greater pace and promote workforce training opportunities in advanced manufacturing and the use of mass timber in construction.
Sustainable sourcing: The Oregon Department of Forestry will receive funding to implement forest restoration projects within the Willamette National Forest to improve resilience, reduce wildfire risk, and provide a sustainable supply for mass timber production. Resilience treatments will utilize a materials track-and-trace program to provide utilization and resource accountability.
Smart forestry initiative: OSU will receive funding for research and development to modernize forest restoration practices, including improved forest inventory mapping, enhanced forest worker health and safety, and efficiency within wood supply chain activities. OSU also will develop workforce training curriculum to help promote employment in the forest and wood products industry. “From forests to manufacturing to the construction site, we have designed a holistic suite of investments that create benefits across the supply chain,” said Iain Macdonald, Director of the TallWood Design Institute.
Model development codes: The Department of Land Conservation and Development will modernize development codes to support the use of mass timber in newly built modular workforce housing in 10 communities, prioritizing those impacted by the 2020 wildfires. This will serve as a model for other communities looking to accelerate housing production using mass timber.

For more information about the Oregon Mass Timber Coalition, visit www.masstimbercoalition.org/projects.

For more information about the Port of Portland’s focus on mass timber, visit www.portofportland.com/masstimber.

As one of the world’s premier centers of forestry education and research, the OSU College of Forestry is a recognized leader in sustainable forestry, sustainable land management solutions, climate-friendly forest products, green building, and smart recreation and urban planning: a comprehensive breadth of expertise necessary to develop the principles, practices, processes and products that improve rural and urban livelihoods while protecting the environment.

Our research is carried out by faculty, staff and students and happens in classrooms, labs, on public and private lands across the state, in the College’s own 15,000 acres of Research Forests and in our 11 research cooperatives.

The College of Forestry received over $14.7 million in research grants and contracts for FY 2022. The awards support College of Forestry research that advances scientific knowledge critical to the health of forests, people and communities.

Here are some examples of the new awards:

“Reconciling timber production and biodiversity conservation : Testing the Triad approach to providing ecosystem services”
Sponsor: USDA National Institute of Food and Agriculture
Principal Investigator: Matt Betts

“DISES: Modeling interactions between community forest dynamics and local livelihoods amidst institutional changes”
Sponsor: National Science Foundation
Principal Investigator: Reem Hajjar

“Assessing post-fire land management practices to improve recovery of soil health, vegetation, and ecosystem services”
Sponsor: USDA National Institute of Food and Agriculture
Principal Investigator: Kevin Bladon

“Predicting Near Real-Time Post-Fire Debris Flow Along ODOT Corridors”
Sponsor: Oregon Department of Transportation
Principal Investigator: Ben Leshchinsky

“Collaborative Research: Will it stay, or will it go? And if it goes, when? Parameterizing the Drivers and Timing of Post-Earthquake Landslides”
Sponsor: National Science Foundation
Principal Investigator: Ben Leshchinsky

“Evaluating the response of native pollinators to fuel-reduction treatments in managed conifer forests”
Sponsor: CAL FIRE
Principal Investigator: Jim Rivers

No one loves mushrooms as much as Ray Van Court loves mushrooms.

Their favorite food? Matsutake mushrooms. Their favorite hobby? Mushroom hunting. Their favorite time of the year? Mushroom season.

In fact, Van Court loves mushrooms so much they quit their corporate job to pursue ways to make the world a better place through fungi.

As a PhD candidate in wood science and graduate research assistant, Van Court is working on a project with assistant professor of forest-based bio-products Gerald Presley. Together, they use ectomycorrhizal fungi to bioremediate heavy metal-treated wood waste.

“Preservatives are critical to retaining the structural integrity of wood, but disposal of treated wood is problematic,” Van Court says. “Wood treated with metals including arsenic and copper is disposed of in landfills, often unlined, where these toxic metals can move into the environment. Preventing the migration of these metals, and potentially recovering them, could reduce the ecological impact of these contaminants.”

Certain species of ectomycorrhizal fungi are known to tolerate high metal environments, and initial work has shown that they may reduce metal toxicity. These mechanisms include binding them, transporting them, and producing compounds that stabilize the metals. Introducing fungi particularly adept at immobilizing metals in contaminated sites could reduce the environmental impact of toxic metal migration. The resulting retention of bound metals may also allow for reclamation.

This, says Van Court, represents a long-term solution to the problem of treated wood waste with little required inputs – all ectomycorrhizal fungi need is trees to associate with.

To test this idea, Van Court and Presley are performing a multi-stage lab experiment, screening 20 different species of ectomycorrhizal fungi in plate culture against three toxic metals.

“This screening will identify which species best tolerate and uptake metals used in wood preservatives and is an enormous increase in species and metals compared to previous research,” says Van Court.

In the second stage of the research, trees will be inoculated with the best performing fungi and planted in heavy metal-treated mesocosms, controlled containers that replicate natural environments. Trees and fungi will grow together in the metal contaminated system for a few months, after which their effect on metal will be measured. This initial work will test the effectiveness of the fungal system and pave the way for future field research.

While doing the research, Van Court was surprised by the scarcity of technologies related to ectomycorrhizal fungi and the limited knowledge on fungi growth. The fungi are usually in symbiosis with trees and for many species very little is known regarding how to replicate what the tree or other organisms in the ecosystem typically provide to the fungus.

“Admittedly, they are much harder to grow and maintain than decay fungi, but they represent a lot of untapped potential,” Van Court says. “As all kinds of products – from medicines to packaging material – have come from decay fungi, what new sustainable products might come from ectomycorrhizal ones? With new analytical and genetic tools, I think we are poised to learn much more about these fungi, and I am excited to see where this research and other projects can go.”

A version of this story appeared in the Spring 2022 issue of Focus on Forestry, the alumni magazine of the Oregon State University College of Forestry.

Nathan Vega, an undergraduate student double majoring in renewable materials and forestry, has always had an interest in the fields of renewable energy and forest-based bioenergy.

“I am especially interested in biochar for its potential to help with wildfire prevention, energy production and agricultural management,” Vega says.

Biochar is a carbon-rich, charcoal-like substance made by burning organic material, like agricultural or forestry waste, at low oxygen levels in a process called pyrolysis. Biochar can be used as a soil enhancer or as a way to sequester carbon. The energy or heat created during the conversion can also be captured and used as clean energy.

“Biochar is part of something called the circular economy,” Vega says. “And the foundation of this economy is a transition to renewable energy and materials.”

An alternative to the traditional linear economy, the circular economy is restorative or regenerative by design. It seeks to reduce waste and material use, recover resources at the end of a product’s life, and channel them back into production, significantly reducing pressure on the environment.

Vega jumped at an opportunity to work within the circular economy, assisting Scott Leavengood, director of Oregon Wood Innovation Center, in testing Portland, Oregon, based Sankofa Lumber’s new line of panel products known as “SecondStory.”

“SecondStory” panels are unique in that they are composed of reclaimed structural building materials, including lumber, oriented strand board (OSB) and plywood. Sankofa refers to these panels as architectural surfaces and advises using them for purposes like flooring, casework and wall cladding. “SecondStory” panels are currently installed in the Oregon State women’s gymnastics facility locker room.

Leavengood and Vega tested the panels to determine qualities like hardness, bond and bending strength and moisture performance. They measured the panels’ performance based on comparable products like
particleboard, medium-density fiberboard (MDF) and hardwood plywood. The Cascadia CleanTech Accelerator, powered by VertueLab and CleanTech Alliance, funded the testing.

“For entrepreneurs working with any kind of new material or new product, the first question they always get from potential customers is ‘what’s it like?’ or in other words, how does the product compare to what’s on the market now?’ says Leavengood. “We were able to help Sankofa Lumber answer these questions since Nathan put the product through a workout.”

Bond strength is critical for composite products. Leavengood and Vega found the strength excellent even after products were exposed to high humidity and water submersion for several days.

Focusing on his classes and assisting Leavengood with his research projects provided Vega with support and something to focus on during the pandemic.

“Everyone at the College of Forestry was very welcoming and friendly,” Vega says, “Plus, this job was a great part of the last year-and-a-half as it let me get out of the house and listen to music while I did the experiments.”

Vega is a recipient of the Friends of Renewable Materials Seneca Scholarship, Powers Scholarship, and Presidential Scholarship from the College of Forestry. He said receiving the scholarships has been essential to ensuring his success at Oregon State.

“These scholarships have allowed me to pursue my education without distraction or worry,” Vega says. “It’s been such a relief to find that I am so supported.”

When Vega is not studying, he likes to spend his free time reading, gardening, cooking, listening to music, hiking and playing the drums. He also likes to spend his time with his friends and family and he recently joined the college’s logging sports team.

After graduation, Vega wants to work in bioenergy, specifically biochar production from forest biomass as a carbon-negative energy source.

A version of this story appeared in the Spring 2022 issue of Focus on Forestry, the alumni magazine of the Oregon State University College of Forestry.

Christopher Still, a professor at the Oregon State University College of Forestry, studies forest ecology and the physiology of trees. His research spans from a singular leaf on a tree to entire ecosystems. He also studies carbon cycling and forest-climate interactions.

So, when the temperatures rose to unprecedented levels in the summer of 2021 and a heat dome descended upon Oregon, Still knew the scorching heat and intense energy from the sun would stress the trees, scorch the foliage and impact Oregon’s forests. Especially after two years of state-wide drought. But at what scale? And what would that mean for the long-term health of the trees?

“The ‘heat dome’ led to numerous reports of foliage scorch and leaf drop in westside forests of the Coast Range and Cascades,” Still said. “Western hemlock and western red cedar seemed to be impacted the most, but Douglas-fir and various alders and maples were affected, too. Notably, trees and saplings with direct solar exposure and on south-facing slopes seemed to suffer the worst foliage scorch.”

With help from citizen scientists, researchers like Still spent months documenting the heat dome’s effects on Oregon’s trees. Using a website created by the Oregon Department of Forestry, community members and researchers reported their observations to map and analyze the foliage scorch.

Still then organized a symposium to share information and begin piecing together what the heat dome event might mean for the long-term health of trees.

“Researchers do not know what the near- and long-term physiological causes and consequences of foliage scorch and heat stress will be, at either leaf or tree scales. The impacts could range from impaired metabolism on surviving leaves, to reduced stem diameter growth, to eventual tree mortality,” Still says.

The symposium served as a central place for tree experts like foresters, silviculturists and botanists to meet and discuss their findings and plan for the next steps to monitor the impacts of the heat dome.

“I think there are many challenges for forest management. The challenges range from trying to help forests become more resilient to climate change impacts, to working on assisted migration and planting of new genotypes and identifying species that can better handle a warmer and drier climate in the future,” Still says.

Still says we should expect more intense heatwaves in the future, and we should all work urgently to lower our carbon footprint to mitigate future climate change.

However, he said the data shows there is much to learn about heat stress physiology and how different genotypes, species and forest types will respond to future heat and drought extremes.

“I think the scale of the impacts – both the spatial scale and the range of species and forest types affected – was surprising. I think the resilience shown by some species and forests was also a pleasant surprise,” Still says.

A version of this story appeared in the Spring 2022 issue of Focus on Forestry, the alumni magazine of the Oregon State University College of Forestry.

Swiss needle cast, a foliage disease specific to Douglas-fir resulting in needle loss and reduced growth, is perhaps the most well-studied foliage disease globally. Knowledge about this disease, caused by the native pathogenic fungus Nothophaeocryptopus gaeumannii, is used to study other foliage diseases worldwide.

This is due to the influence of the Swiss Needle Cast Cooperative at Oregon State University. “Since 1996, the cooperative has been focused on research and management of Douglas-fir in zones where Swiss needle cast occurs,” says professor and forest health specialist Dave Shaw, the current director of the cooperative.

Now, a quarter of a century later, the cooperative has published an article in the Journal of Forestry, summarizing their current understanding of Swiss needle cast based on twenty-five years of research.

Swiss needle cast, considered one of the top threats to Douglas-fir plantation health and productivity in western Oregon, Washington and SW British Columbia, was first identified on Douglas-fir growing in Switzerland in the early 20th century. Forest pathologists in North America found the fungus was common in native Douglas-fir stands but was not causing problems.

The disease emerged in Christmas tree plantations in Washington and Oregon in the 1970s, and by the 1990s, it had intensified in coastal Oregon and Washington Douglas-fir plantations. In January 1997, in response to the disease epidemic, the Swiss Needle Cast Cooperative was formed by private forest landowners, federal and state agencies, and the Oregon State University College of Forestry to conduct research and address management practices.

“The more we learn, the better we will be able to sustain the productivity of our forests,” Shaw says. “However, this is a native disease that has a role here in the PNW, and we have some ability to manage forests effectively in the presence of the disease.”

Swiss needle cast symptoms include chlorotic, yellowish foliage, low needle retention, thin crowns and reduced tree growth. The fungus occurs wherever its only host, Douglas-fir, is grown. Disease, however, is only expressed when the fungus causes significant defoliation of two and three-year-old needles.

This, says Shaw, is an essential point for managers. The fungus may be present and yet have no effect on Douglas-fir productivity.

The fungus lives inside the needles of Douglas-fir. It only impacts needle function when fungal fruiting bodies called pseudothecia emerge into and plug the stomates, or air pores, on the underside of the needle, blocking gas exchange. When too many stomates on a needle get plugged, the needle dies and is cast, or dropped, from the branchlet.

Even after twenty-five years of research, Shaw says the science can still be surprising.

“We recently found that Swiss needle cast is distinctly a young tree disease, and older stands, except in extreme examples, are not as affected. There is something unique about young stands that makes the disease more prevalent,” Shaw says. This work was based on collaborations between graduate student Sky Lan, Shaw, and scientists from the Environmental Protection Agency who climbed mature and old-growth trees over two hundred feet tall to get samples and measure microclimate.

While Shaw and others do not yet know why this disease affects younger trees more often, they hypothesize the difference may be due to temperature dynamics within the canopy.

According to Shaw and Gabriela Ritokova, the associate director of the cooperative and a forest pathologist with the Oregon Department of Forestry, the management of Swiss needle cast is nuanced and site-specific. A “Guide to the Silviculture of Swiss Needle” is available on the Swiss Needle Cast Cooperative website.

Shaw explains that future challenges include understanding how climate change will influence the disease.

“Epidemiology-wise, winter temperature, and late spring-summer leaf wetness control disease,” Shaw says. “As we continue to increase winter warming, we may see the disease spread from the core areas now impacted to higher elevations and the western Cascades.“

A version of this story appeared in the Spring 2022 issue of Focus on Forestry, the alumni magazine of the Oregon State University College of Forestry.

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Category Archives: research

Pollinators in the Forest

What I did this summer: Ashley D’Antonio

Over $41 million awarded to accelerate use of mass timber to restore forests, create jobs and address housing

Ensuring Water Security with Increasing Wildfire Threats in the Western US

Oregon Mass Timber Coalition Awarded Funds to Create Jobs and Address Housing

FY 2022 Research Awards

More to mushrooms than meets the eye

Advancing the circular economy

Some like it hot: PNW trees like it temperate

25 years of global leadership, and it started in our own backyard

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