USDA Forest Service

Pacific Northwest Research Station

Pacific Northwest Research Station
1220 SW 3rd Ave.
Portland, OR 97204

(503) 808-2100

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» Research Highlights

Combatting illegal logging

Tracking the origin of wood using chemical fingerprints


Douglas-fir wood in cross section. Photo credit: Edgard Espinoza, 2017.
Douglas-fir wood in cross section. Photo credit: Edgard Espinoza, 2017.

Illegal logging is the harvesting of wood in violation of national laws and regulations. It includes cutting protected species or removing wood from restricted areas. Illegal logging seriously threatens biodiversity and costs governments and businesses $10 to $15 billion annually. The Convention on International Trade in Endangered Species and the U.S. Lacey Act protect tree species at risk of exploitation. But enforcing these regulations is challenging, as it is often nearly impossible to tell where a piece of wood came from. Research geneticist Richard Cronn, working with colleagues from Oregon State University and the U.S. Fish and Wildlife Service, has developed a technique that uses the chemical fingerprint of a wood sample to pinpoint its origin.


Cronn and his team used Douglas-fir in the Coast and Cascade Ranges to test the effectiveness of this technology in revealing fine-scale geographic variation in wood chemistry and genetic markers. Douglas-fir is a widespread and economically important tree in the Pacific Northwest, and an attractive target for poaching in national forests and parks. They found that chemical fingerprints can accurately determine the geographic source of Douglas-fir wood 75 percent of the time. Chemical analysis takes seconds to perform, making it a promising “rapid screening method” for forensic wood identification. By combining chemical and genetic data, higher precision taxonomic and geographic source identification should be possible. This technology is being adapted for other economically important trees that are the targets of illegal logging activity.

Contact: Richard Cronn,


More information:  Source identification of western Oregon Douglas-fir wood cores using mass spectrometry and random forest classification.


Climate change and the world’s forests

Modeling mitigation scenarios


Forest and climate interactions are complex. Photo credit: Eirik Luka via Compfight cc.
Forest and climate interactions are complex. Photo credit: Eirik Luka via Compfight cc.

The past century has been the warmest in the history of modern civilization. And 16 of the 17 warmest years on record globally have occurred since 2001. How will the changing climate shape future forests? Ecological modeler John Kim addresses this question in his work with the Western Wildland Environmental Threat Assessment Center and the Pacific Northwest Research Station. He studies climate change impacts to vegetation using dynamic global vegetation models (DGVMs). Modeling the Earth's climate is one of the most highly complicated endeavors in science. But DGVMs provide a way to improve understanding of the interactions between two very complex systems: forest ecosystems and climate. These computer programs simulate forest responses to climate by modeling vegetation dynamics, biogeochemistry, biophysics, and the distribution of vegetation over geographic space.


Kim recently led a study simulating possible impacts of climate change on the world's forests, using a DGVM that simulates future potential changes in terrestrial ecosystem productivity, climate-driven vegetation migration, wildfires, the resulting competition between vegetation types, and the associated forest regrowth and carbon dynamics. His team characterized forest responses to climate change for various global forestry regions and looked at the potential impact of mitigation actions. They found that even though climate mitigation policies may be effective at reducing changes in temperature, precipitation, and carbon dioxide concentrations, forest biomes may still be significantly altered by climate change. For example, temperate forest regions are projected to see strong increases in productivity offset by carbon loss to fire and increasing competition from the Southern Hemisphere in soft wood products.


Contact:  John B. Kim


More information: Assessing climate change impacts, benefits of mitigation, and uncertainties on major global forest regions under multiple socioeconomic and emissions scenarios


Flowering in the cold North

Climate implications for Arctic plants


Papaver radicatum flowering at Alexandra Fiord, Canada. Photo credit: Anne Bjorkman.
Papaver radicatum flowering at Alexandra Fiord, Canada. Photo credit: Anne Bjorkman.

Climate change is altering life for plants, animals, and people in the Arctic. As the planet warms, some species respond by migrating to environments better suited to their habitat needs. Many plants are also shifting the timing of their biological cycles (known as phenology), such as the times of year when they leaf out and flower. Research ecologist Janet Prevéy is helping to unravel the relationship between temperature change and the timing of ecologically critical events in the life cycles of plants in the Arctic.


Plants adapted to cold environments have short growing seasons and are under strong selective pressure to start growth and flowering just as soon as temperatures allow. Prevéy led one of the first studies ever to examine whether the temperature sensitivity of these life events differs among tundra sites experiencing different climatic conditions. Her work made use of the largest collection of high-latitude field data on plant phenology, collected by hundreds of scientists and field assistants. By analyzing up to 20 years of data on the dates when leaves and flowers appear and die for 47 species of tundra plants at different sites and elevations, Prevéy tested the hypothesis that plants from colder sites would be more sensitive to temperature change shown in the timing of leafing out and flowering than plants from warmer sites. She and her team found evidence across species for greater temperature sensitivity of greening and flowering phenology of tundra plants in colder, higher latitude sites than at warmer, lower latitude sites. They also found that the temperature increase in spring and early summer over the past 50 years has been greater in colder, higher latitude sites than in warmer, lower latitude sites.


These are among the first results to document differing responses of tundra plants across a climatic gradient. Interestingly, Prevéy’s results also suggest that as summer temperatures create more overlap between flowering times of plants from colder and warmer sites, gene flow between populations could increase.


Contact: Janet Prevéy,


More information: Greater temperature sensitivity of plant phenology at colder sites: implications for convergence across northern latitudes

Intentional use of wildfire

What about the public health impacts?


Nuns Fire near Napa, CA 2017. Photo credit: USDA, Lance Cheung.
Nuns Fire near Napa, CA 2017. Photo credit: USDA, Lance Cheung.

Wildfires are getting larger, more frequent, and more severe in many places in the West. This means more smoke, which has become a public health concern for communities downwind of large wildfires. Ecologist Jonathan Long recently led a study exploring strategies for using prescribed fires and unplanned wildfires to increase ecological resilience, while also protecting air quality. He and his co-authors showed that by using fire under favorable weather and fuel conditions, large areas of forest can be treated while keeping daily emissions below levels that are likely to cause harm to people in downwind communities. They described a framework that aligns ecological and public health goals through the following actions: assessing fires based upon their risks to human health rather than the size of the area burned, pacing fire spread based on airshed capacity to disperse the resulting emissions, and communicating with the public to reduce the exposure of downwind populations.


Long and his team applied the framework retrospectively to compare differences in smoke impacts between resource objective wildfires and full-suppression wildfires within the San Joaquin River watershed in California’s Sierra Nevada. They found that an extreme wildfire like the Rim Fire not only affected millions of people in California and Nevada, but also that its smoke impact per unit area burned was several times greater than fires used to achieve resource objectives in the same area. Land managers are now applying their strategy to minimize smoke impacts to downwind communities from burning over 4,000 acres around Caples Lake in the Sierra Nevada in California.


Contact:  Jonathan Long,


More information: Aligning smoke management with ecological and public health goals

What's New

New video introducing fire scientists


Watch fire ecologists Morgan Varner and Morris Johnson describe their research. They address some challenging management questions related to wildfire, such as: how does fire affect wildlife habitat and other things we care about? How do fuel treatments affect fire behavior? Find out a little bit about these PNW Station scientists and what it’s like to study wildfire, fuel treatment effectiveness, and fire behavior.




Mount St. Helens High School STEM Field Ecology Program


PNW Station ecologist Charlie Crisafulli leads a discussion with STEM students at Mount St. Helens. Photo credit: Ray Yurkewycz, Mount St. Helens Institute.
PNW Station ecologist Charlie Crisafulli leads a discussion with STEM students at Mount St. Helens. Photo credit: Ray Yurkewycz, Mount St. Helens Institute.

In September 2017, high school students in the STEM (science, technology, engineering and math) Field Ecology Program enjoyed a multiday field experience at Mount St. Helens National Volcanic Monument.

This program engages students in field-based ecological projects and subsequent analyses, interpretation, and presentation. Students develop critical thinking skills and get to connect with a wide variety of science professionals. Over the years, 700 students and nine teachers have conducted relevant field research at Mount St. Helens with natural resource professionals from a variety of public and private entities. The STEM program is organized by the Mount St. Helens Institute.





Featured Scientist

Richard Cronn, Research Geneticist.New technologies and discoveries are continually advancing our understanding of genetics. Research geneticist Richard Cronn works at the frontier of this exciting field, contributing new knowledge about genetics and genomic methods and how they can support forest and rangeland management. Stationed at the Corvallis Forestry Sciences Laboratory, he leads the Cronn Lab, where he oversees research on population genetics, plant evolutionary genetics, and molecular genetics.


Cronn is primarily interested in how perennial plants sense and respond to stressful environmental signals (light, temperature, moisture), cyclic signals (seasons), and how these responses contribute to local adaptation. Some of his work involves developing genetic markers for domestic and international trees, plants, and animals of management concern.


As just one example of this research, Cronn and his colleagues sequenced all the expressed genes from Douglas-fir to create a transcriptome atlas. A "transcriptome" is the collection of genes an organism is expressing at any given point in time, reflecting its response to environmental cues like stress. The Douglas-fir atlas can help forest managers enhance traditional breeding methods and make this ecologically and economically important species healthier and more productive in future climates. He has also collaborated with other Forest Service research stations and universities on the Western Forest Transcriptome Survey, a massive undertaking to sequence genes from a variety of plants, animals, and pathogens to identify genes and gene networks that are temperature responsive and therefore able to contribute to climatic adaptation.


Cronn’s research extends to a number of non-model forest plants and animals. He and his team characterized the aspen leaf transcriptome, opening the door for gene expression studies of a species that may be an important study system for forest responses to climate change. He has conducted a genetic analysis of yellow-cedar, another tree species that is responding to climate change in Alaska. He also helped sequence entire mitochondrial genomes from 40 fishers, closing a knowledge gap about genetic variation between different fisher populations, and revealing that their observed genetic structure has been in place for thousands of years.

In addition to these applied studies, he has advanced the science of plant genetics. For example, he pioneered the technique of using of low-copy nuclear sequences for phylogenetic studies. He also helped to uncover patterns of duplicate gene expression in cotton (reciprocal silencing of duplicates in polyploids)—an advance that has far-reaching implications for understanding plant evolution, domestication, and crop improvement.


The study of genetics is important for forest management. Cronn's research contributes to a better understanding of the distribution, evolution, and health of wild plants and animals and their ability to adapt to changing environmental conditions over time.



US Forest Service - Pacific Northwest Research Station
Last Modified: Wednesday,06December2017 at16:24:15CST

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