New evidence suggests that a disease-causing tapeworm that has been spreading across the United States and Canada has arrived in the Pacific Northwest. The tapeworm, called Echinococcus multilocularis, lives as a parasite in coyotes, foxes and other canid species and can cause severe disease if passed to domestic dogs or humans.

E. multilocularis has long been recognized as a public health threat in parts of the Northern hemisphere, including Europe and Asia, but was considered extremely rare in North America until approximately 15 years ago, when cases in humans and dogs began cropping up in Canada and the midwestern U.S., indicating that the parasite was spreading.

This study, led by ����Ӱ�Ӵ�ý researchers, is the first to detect E. multilocularis in a wild host on the west coast of the contiguous U.S. Researchers surveyed 100 coyotes in the Puget Sound region, and found E. multilocularis in 37 of them. The results were .

“This parasite is concerning because it has been spreading across North America. There have been numerous cases of dogs getting sick, and a handful of people have also picked up the tapeworm,” said lead author , who recently graduated from the UW with a doctorate in environmental and forest science. “The fact that we found it here in one-third of our coyotes was surprising, because it wasn’t found anywhere in the Pacific Northwest until earlier this year.”

When E. multilocularis infects an animal or person, it causes cancer-like cysts to form in the liver and sometimes other organs. If untreated, infection can be fatal.

However, not all carriers become sick. E. multilocularis has a complex life cycle that involves multiple hosts. Canids, which host adult parasites, can support thousands of worms in their intestines without becoming sick. The worms shed eggs that are then passed in their feces.

Rodents — another host — become infected by eating food contaminated with coyote feces. Once consumed, the parasite eggs migrate to the liver and form cysts, ultimately weakening or killing the rodents. The parasite’s life cycle begins again when coyotes prey upon infected rodents.

Humans and domestic dogs are categorized as accidental hosts. Humans may pick up the parasite by consuming tapeworm eggs — in food that is contaminated with coyote or dog feces, for example — and can develop a disease called , characterized by slow-growing metastatic cysts. Symptoms may not appear for five to 15 years after exposure, which complicates diagnosis and treatment.

Alveolar echinococcosis is considered the third most important food-borne illness globally, and one of the top 20 neglected tropical diseases by the World Health Organization. Many countries have developed robust protocols for tracking it.

Domestic dogs that are exposed to E. multilocularis may or may not become sick, depending on where the parasite is in its life cycle at exposure. It is more common for dogs to carry the parasite and shed eggs without developing disease, but dogs that are exposed to parasite eggs may develop the same cancer-like cysts as other infected animals.

“To minimize the risk of dogs getting infected with E. multilocularis, owners should not let them prey on rodents or scavenge their carcasses,” said co-author , an associate professor and director of the Parasitology Diagnostic Laboratory at the Texas A&M University College of Veterinary Medicine and Biomedical Sciences.

Owners can also give dogs preventative medication for worms and ticks and ensure routine veterinary care, which should include diagnostic tests for parasites, Verocai said.

Although the researchers found E. multilocularis in more than one-third of local coyotes tested, there is little evidence of the infection spreading to other hosts. One study in Washington, Oregon and Idaho since 2023, five of which were in Washington. Few human cases have been reported in the U.S., and none on the West Coast.

“The reason that it’s so high in coyotes is because they are regularly eating raw rodents, and that is the primary way for them to get infected. Most domestic dogs are not eating the raw livers of wild rodents,” Hentati said.

Before the uptick in the 2010s, there were several reports of E. multilocularis on remote islands in northwestern Alaska. Those cases were caused by a parasite with different origins than the current outbreak. Genetic analysis pins the earlier cases to a tundra variant while these recent cases are driven by a more infectious variant with European origins. The coyotes in this study carried the newer variant, now thought to be the predominant variant in the U.S. and Canada.

Neither Canada nor the U.S. require dogs to undergo deworming upon arrival, which may explain the spread. Previous studies also proposed that E. multilocularis could have come over in red foxes imported for hunting 100 years ago, but no one knows for sure.

“The main takeaway is that Echinococcus multilocularis is here, it’s pretty prevalent in the local coyote population and people should be aware of potential risks,” Hentati said.

Co-authors include , lab manager at UW; , UW doctoral graduate in environmental and forest science; , a UW professor of environmental and forest science; , a UW associate professor of aquatic and fishery science; of the College of William and Mary; Erika Miller of Sound Data Management; of DePaul University; and of UC Berkeley. This study was funded by The National Science Foundation and the ����Ӱ�Ӵ�ý Hall Conservation Genetics Fund.

For more information, contact Hentati at yhentati26@gmail.com.

Nautilus and Allonautilus cephalopods and their extinct ancestors have been drifting through of the ocean for more than 500 million years. Researchers have spent the last 40 years trying to understand how these mysterious “living fossils” thrive in areas with limited nutrients. published in Scientific Reports, a UW-led team documented new habits and habitats for current Nautilus and Allonautilus species. These creatures appear to live in deeper water than their extinct cousins did, and the younger ones live twice as deep as the fully mature adults. Nautilus and Allonautilus species scavenge their food and never stop moving. While a few species migrate hundreds of meters down at dawn and then back up at dusk every day, the team found that most species aren’t quite as intrepid. The researchers also describe a new population of Allonautilus in waters off the island , one of several populations thriving due to hunting restrictions inspired in part by research efforts from this team.

For more information, contact senior author , UW professor of both biology and Earth and space sciences, at argo@uw.edu.

Other UW co-authors are , and . A full list of co-authors and funding is included

Green clay tennis courts become carbon negative after 10 years

The United States has around a quarter of a million tennis courts, 40,000 of which are helping mitigate greenhouse gas emissions. Green clay tennis courts, an alternative to traditional hard courts and the red clay courts popular in Europe, are constructed with a type of rock that reacts with carbon dioxide and water to sequester carbon as a stable dissolved salt. In , UW researchers show that in the U.S., green clay courts remove 25,000 metric tons of carbon dioxide from the atmosphere each year and 80% of green clay courts make up for construction emissions within 10 years. Moving forward, the researchers hope to experiment with other materials that also remove carbon dioxide without compromising performance for players.

For more information contact lead author , UW assistant professor of oceanography, at fjpavia@uw.edu.

A full list of co-authors and funding is available .

Temperature dynamics, not just extremes, impact heat tolerance in mussels

Intertidal mussels, forming bumpy layers on shoreline rocks, withstand significant temperature swings as the tide ebbs and flows. These creatures live in one of the most thermally variable environments on Earth, but a new study shows that the rate, timing and duration of heating and cooling impact their metabolic rate, a proxy for overall health. At the UW’s , researchers exposed mussels to temperature regimens with equal highs and lows but different patterns of change. Even when the average temperature for a set period was the same, the mussels’ response was distinct. These results, , show that predicting how marine organisms respond to climate change means considering how temperature changes over time, not just how warm it gets.

For more information, contact lead author , assistant professor of biology at the College of the Holy Cross and a mentor for the UW Friday Harbor Laboratories , at mnishizaki@holycross.edu.

The other UW co-author is . A full list of co-authors and funding is available .

When algae stop growing, bacteria start swarming

Tiny geometric algae, called , produce nearly a quarter of the world’s organic matter by photosynthesis. In the microscopic marine universe, diatoms coexist with both harmful and helpful bacteria. A new study, , describes how a recently identified species of marine bacteria targets diatoms based on growth phase and nutrient availability. Growing diatoms can resist bacterial attacks, but when growth ceases, the bacteria modulate their gene expression patterns to become aggressive — first swimming and releasing compounds that damage the diatom and then clustering around them to feed. Bacteria can also overcome the diatom’s defenses in nutrient-rich environments. These findings highlight the dynamic relationship between bacteria and algae in the lab. Moving forward, researchers will explore what, if anything, changes in a more complex environment.

For more information, contact lead author , UW postdoctoral fellow in oceanography, at dawiener5@gmail.com.

Other UW co-authors are and . A full list of co-authors and funding is available .

Humans look to nature for sustenance and nourishment — food, water, energy, transportation, culture, tradition, adventure and so on. With the population of the United States now exceeding 340 million, humans are demanding more of the natural world than ever before. To understand the consequences, researchers set an ambitious goal: a wellness check on nature.

Nature is a sweeping category that includes everything from massive mountains to tiny urban gardens. Its health can’t be summarized in just a few words. In fact, it took researchers 868 pages, split into 13 chapters, to report the condition of lands, waters, wildlife, and biodiversity and describe links to human health and safety, culture, economy, and national security.

The new report, , is available for public comment and scientific review until May 30.

“The Nature Record tells an honest story,”  said , director of The Nature Record and interim executive director of the UW’s EarthLab. “It does not shy away from the scale of change we are seeing in nature — but it also shows that our choices matter, and that there are real, tangible ways to restore and sustain the systems we depend on.”

The preliminary findings are a mixed bag. On one hand, the report details a long history of resource extraction and habitat loss that will be difficult to reverse. At the same time, it shows how restoration and Indigenous stewardship approaches can help turn things around.

For example, the report states that approximately 50% of U.S. land is used for agriculture. This means farmers and ranchers must be involved in efforts to protect ecosystems and preserve biodiversity, Levin said.

The U.S. has millions of miles of rivers, which are fragmented by tens of thousands of large dams and as many as 2 million small dams and culverts.

Damming rivers disrupts fish migration and degrades ecosystem health. Ecological concerns have spurred hundreds of dam removals in the past decade, after which rivers quickly rebounded. In some places, fish have returned to spawning grounds that were inaccessible for generations.

“The assessment documents many examples where ecosystems and communities are recovering together,” Levin said. “These success stories show that change is possible when science, policy and communities align.”

The project began in 2022 following an executive order calling for an assessment of nature. Levin, selected to lead the effort, assembled a national team of experts to work on what was then called the National Nature Assessment.

Then, in January 2025, just weeks before the team was due to deliver a first draft, the effort came to a screeching halt when the federal government canceled the effort.

Undeterred, the team, including more than 170 scientists and experts, decided to continue working independently. They published a draft of The Nature Record in March.

“We built this to be useful,” Levin said. “And the only way it becomes truly useful is if people engage with it — question it, add to it, and help shape what comes next.”

He encourages people of all backgrounds to engage with the report and share feedback on the clarity, relevance and thoroughness, including representation of diverse perspectives.

In addition to documenting how humans are changing nature, the record provides important insights into how nature influences quality of life. Access to nature varies widely across the U.S. — the benefits of nature are not equally shared, nor is the burden of going without. Social and historical factors often determine whether communities enjoy greenspaces and clean drinking water, among other essentials.

“This assessment reflects not just the state of nature, but the relationships people have with it,” said deputy director , principal research scientist at the UW’s EarthLab. “We want people to see themselves in this work — whether through their communities, their values, or the places they care about — and to help shape how it evolves.”

For more information, contact Levin at pslevin@uw.edu.

This winter was ; as a result, many snowy, alpine areas have seen bouts of winter rainfall where there would ordinarily only be snow. These unusual weather patterns have contributed to an abysmal ski season, but they can also set the stage for dangerous avalanches. At temperatures close to freezing, precipitation can fall as rain but freeze when it hits the snow, forming an icy crust. Snow that accumulates on top of that crust is unstable and prone to abrupt slides, causing an avalanche that can close down a major highway in moments, endanger backcountry skiers and more.

Avalanche experts in Western Washington know how to manage the risks associated with rain-on-snow events, but many of their counterparts in colder regions like Eastern Washington, Idaho and Montana are less familiar with these dynamics. New research from the ����Ӱ�Ӵ�ý shows that as winters in these regions warm, their snowpacks may come to resemble those of maritime areas, with more rain-on-snow events, icy crusts and complex avalanche forecasting.��

The findings in ARC Geophysical Research.

“This winter’s warmth is a harbinger,” said lead author , a UW graduate student of civil and environmental engineering. “We know that temperatures will keep rising, and our work is a red flag for cooler regions of the greater Pacific Northwest, such as Idaho and Western Montana, that aren’t used to dealing with ice crusts and their resulting avalanche problems.”

The study is part of a larger effort to understand the structure of snow as it accumulates, which has implications for weather and avalanche forecasting, wildlife dynamics and more.��

“Snow scientists are pretty good at measuring snow depth and volume,” said senior author , a UW professor of civil and environmental engineering. “We’re also pretty good at figuring out how much water you get if all that snow melts. But our models aren’t as good at representing snow structure, such as layers of different densities and crystal types that increase avalanche risks. And we really want to know how the structure of snow changes as the climate changes. That’s a tricky question that no one has tackled, particularly for rain-on-snow conditions.”

To dig into that question, the researchers studied how warming influences ice layer formation in seasonal snowpacks. First, they collected temperature and precipitation data captured by 53 monitoring stations across the Pacific Northwest for the past 25 years. They used a computer model to identify days when ice layers likely formed at each location. They then checked the model against real-world measurements at one of the locations — a station at Snoqualmie Pass — and found that the model matched the measurements with 74% accuracy.

Finally, they used the same model to simulate those same 25 winters at 2 C and 4 C warmer than they were, and looked for changes to the number of ice crusts across the region. , the Pacific Northwest is expected to warm by 2 C to 5 C by 2050 as compared to pre-2000 temperatures.

The results were split regionally by the Cascade mountains. In colder, inland parts of the Pacific Northwest — places like Eastern Washington, Idaho and Montana — higher temperatures created more rain-on-snow days and more avalanche-prone ice layers. Locations in the warmer, maritime Cascades saw the opposite effect: Higher temperatures created slush instead of ice, potentially reducing the avalanche risk associated with ice crusts.��

The predicted snowpack changes may also impact wildlife behavior. Some foraging mammals, such as reindeer, dig down into the snow in search of food and may have a hard time breaking through an icy crust. Conversely, firm ice might provide a better running surface for animals fleeing predators. Specific regional effects will require additional study.

What’s clear now is that those who work or play in avalanche terrain in broad swaths of the Pacific Northwest — and even beyond — may need to adjust to a new set of risk factors.

“I’d love to see this shared with avalanche forecasters widely, both as a call to action and as a way to help them understand what their snowpack might look like in the future,” Alden said.

, the director of geospatial science at Audubon Alaska and former doctoral student of environmental and forest sciences at the UW, is a co-author.

This research was funded by the NASA Interdisciplinary Research in Earth Science program and the UW Program on Climate Change’s Graubard Fellowship.

For more information, contact Alden at cdalden@uw.edu.

Plowing, or tilling, is an age-old agricultural practice that readies the soil for planting by turning over the top layer to expose fresh earth. The method — intended to improve water and nutrient circulation — remains popular today, but concerns about soil degradation have prompted some to return to regenerative methods that disturb the soil less.

In a new study, a team led by ����Ӱ�Ӵ�ý researchers examined the impact of tilling on soil moisture and water retention using methods originally designed for monitoring earthquakes. Researchers placed fiber optic cables alongside fields at an experimental farm in the United Kingdom and recorded ground motion from plots receiving different amounts of tillage and compaction from tractor tires pulling farm equipment.

The study, , shows that tilling and compaction disrupt intricate capillary networks within the soil that give it a natural sponge-like quality.

“This study offers a clear explanation for why the process of tillage, one of humanity’s oldest agricultural activities, changes the structure of soil in ways that affect how it soaks up water,” said co-author , a UW professor of Earth and space sciences.

The link between tilling and soil degradation has been established for quite some time, but the rationale is less robust.

“It’s counterintuitive,” Montgomery said.

Tilling is supposed to create holes for water to reach the roots of plants, but it breaks these small channels in the soil instead, causing rain to pool on the surface and form a muddy crust. Over time, this can increase erosion and flood risk. The researchers observed this phenomenon in detail using seismological methods.

For the past decade or so, physical scientists have been exploring ways to harness the fiber optic cable network to make remote observations. They use a technique called distributed acoustic sensing, or DAS, that records ground motion based on cable strain. Because the technology is so sensitive, it can also capture the speed at which sound waves pass through a substance, which is called seismic velocity.

When soil gets wet, seismic velocity changes. Sound moves slower through mud than dry dirt.

“We wanted to find out whether seismic tools could be used to understand how soil — under different treatment regimens — would respond to environmental variability,” said senior author , a UW associate professor of Earth and space sciences.

An experimental farm near Newport in the United Kingdom, affiliated with Harper Adams University, turned out to be an ideal testing ground for their experiment.

The farm is split into rows that have received consistent cultivation for more than two decades.

There are no-till rows, rows tilled 10 centimeters deep and rows tilled 25 centimeters. Compaction is a byproduct of tilling caused by tractors. Different levels of compaction were tested by modulating tractor tire pressure.

“We took advantage of a natural experiment that had already been done, but just not yet measured,” Montgomery said.

The researchers lined their experimental plots with a fiber optic cable. They collected continuous ground motion data for 40 hours and combined it with weather data over the same period, which featured light to moderate rainfall and mild temperatures.

“We observed the natural vibration of the ground and found that it is really sensitive to environmental factors, including precipitation,” said , lead author and former UW postdoctoral researcher of Earth and space sciences, now at the Chinese Academy of Sciences.

They determined how each cultivation strategy impacted the soil’s response to rainfall by comparing trends in seismic velocity across study sites. Shi developed various models to process the data and help the researchers understand seismic velocity in terms of soil moisture.

The method is straightforward, inexpensive and offers far better spatial and temporal resolution than previous monitoring tools.

The researchers believe it could help farmers understand how to manage their land, provide real time flooding alerts, improve earth systems models by refining estimates of atmospheric water content and better inform seismic hazard maps with data on liquefaction risk.

Additional co-authors include , a UW professor of atmospheric and climate science, , a UW research assistant professor of civil and environmental engineering, from the University of California Santa Cruz, formerly at Purdue University, , , and from Harper Adams University, from the University of Exeter 

This study was funded by The Pan Family Fund, the Murdock Charitable Trust, the UW College of the Environment Seed Fund, the David and Lucile Packard Foundation, and a National Environmental Research Council cross-disciplinary research capability grant.��

For more information, contact Denolle at mdenolle@uw.edu.��

Stark black against an open sky, common ravens are often spotted soaring above wolves in Yellowstone National Park. Researchers assumed that the notorious scavengers were following the wolves to get their scraps, but new research reveals a twist: Ravens don’t follow wolves, they remember common hunting grounds and regularly check back for fresh meat.

When food is easy to find, animals save energy by memorizing the path to retrieving it. Because scavengers rely on other animals to eat, their meals are less predictable. Some scavengers contend with this insecurity by tailing predators, but as this study shows, ravens don’t. Researchers tracked 69 ravens and 20 wolves across Yellowstone National Park for two and a half years and found that the ravens knew where to go without cues from the wolves.

“Scavengers are not quite as glorious as predators, and have traditionally been understudied by comparison. Getting a better understanding from the scavengers’ viewpoint might give us insight into sensory abilities, underappreciated environmental cues and spatial and temporal memory,” said , a ����Ӱ�Ӵ�ý professor emeritus of environmental and forest sciences and the study’s senior author.

March 12 in Science.

Ravens and wolves pick at the scraps of a wolf kill in Yellowstone National Park. Credit: Bob Landis

The mutualistic relationship between ravens and wolves has fascinated humans for centuries. According to Norse mythology, the god Odin created two ravens — — to travel the world gathering intelligence for him. Odin sent his two wolves, , with the ravens to ensure they remained fed.

“This tight coevolutionary relationship between predator and scavenger has persisted in human thought for millennia,” Marzluff said.

Modern scientific research documents a similar relationship between the two species. Ravens have been known to follow wolf tracks through the snow and respond to howls. After wolves were reintroduced to Yellowstone National Park in 1995, ravens were a wolf than anywhere else in the park. The odds of seeing a raven further increase when wolves are hunting.

Marzluff, who is well known for studying crows and ravens, teamed up with lead author , an assistant professor at the University of Veterinary Medicine Vienna then the Max Planck Institute of Animal Behavior, to study how ravens track wolves so well.

The wolves in Yellowstone are already closely monitored, but the researchers needed data on the ravens to compare. Over a few months, Marzluff and Loretto trapped 69 ravens and outfitted them with small GPS trackers. For two and a half years, the researchers monitored where the ravens and wolves went, which routes they took and when their paths crossed.

They only documented one instance of a raven following a wolf for an extended period, yet overall, ravens still managed to arrive promptly after the wolves made a kill. Ravens were spotted at nearly half the observed wolf kills within seven days and some flew more than 150 kilometers to reach a kill. Their flight patterns also suggested that the ravens were making a beeline instead of conducting a sweep.

Ravens were also far more likely to visit areas where wolf kills were more frequent, per the researchers’ “carcass abundance map,” which split the territory into nine square kilometer parcels and plotted kill sites.

The authors propose that ravens rely on spatial memory — the brain’s ability to follow directions — to monitor the wolves’ favorite hunting grounds. Their hypothesis is further supported by data showing that ravens fly over common kill sites en route to other food sources, including areas where humans hunt wild game.

“We already knew that ravens can remember stable food sources, like landfills,” Loretto said. “What surprised us is that they also seem to learn in which areas wolf kills are more common. A single kill is unpredictable, but over time some parts of the landscape are more productive than others — and ravens appear to use that pattern to their advantage.”

Additional co-authors include and from the Senckenberg Biodiversity and Climate Research Centre; , and Lauren Walker from National Park Service and and from ​​Max Planck Institute of Animal Behavior.

This study was funded by the European Union, the National Geographic Society, the German Research Foundation, the James W. Ridgeway endowment to the School of Environmental and Forest Sciences at the ����Ӱ�Ӵ�ý and Yellowstone Forever.

For more information, contact Marzluff at corvid@uw.edu or Loretto at  matthias.loretto@vetmeduni.ac.at.

This story was adapted from by Max Planck Institute for Animal Behavior.

[April 6] UPDATE: Flower petals are falling on the Quad as the trees lose their blossoms. The waning bloom is still quite a site but it’ll be a while before the trees are back on full display.

[March 23] UPDATE: The cherry trees are officially in peak bloom! Visit campus anytime in the next week or so to see the blossoms in all their glory.

[March 18] UPDATE: Recent temperature swings have slowed bud development for the Quad cherries. About half of the trees are still in peduncle elongation stage while half have moved on to the “puffy white” stage that precedes full bloom. Cool temperatures in the coming days may delay peak bloom as trees gradually blossom. Warm weather could produce a sudden transition. Check the live cams for updates.

[March 13] UPDATE: It’s snowing but the blossoms are still growing! The Quad cherries are now in the “peduncle elongation” stage, where the flower-bearing stalk extends from the bud. Some have also begun to flower.

Each spring, large crowds gather on the ����Ӱ�Ӵ�ý Quad to admire 29 puffy pink cherry trees making their seasonal debut. The trees begin to wake up as the weather warms, and this year, estimates suggest that they will reach “peak bloom” on March 20.

The UW’s iconic cherry trees achieve peak bloom when 70% of the blossoms have opened, but the week before and after still offer visitors an optimal viewing experience.

The cherry blossom visitors’ website provides updates on bloom status as well as details on transportation, activities and amenities. The cherry blossoms also have live video feeds for virtual viewing and their own social media accounts on and .

The cherry trees are both beautiful and ecologically significant. Tracking when the buds burst each year helps researchers predict peak bloom and determine how climate warming is impacting the trees, which were planted in the Washington Park Arboretum in 1936 and then relocated to UW in 1962.

This year, many plants began to emerge early as a mild winter gave way to spring. Recent UW research described how plants rely on both temperature and light cues to time their flowering. Temperature is particularly important to cherry trees, which estimate the arrival of spring based on how cold it has been. They accrue “chilling units” as winter progresses and “heating units” as it yields to spring.

“The buds need to accumulate a specific amount of chilling units before they can start accumulating the heating units. When it is not as cold, the chilling units accumulate much slower, so it takes them longer to wake up from dormancy, which is very counterintuitive,” said , a UW doctoral student of environmental and forest sciences.

Theil is now overseeing data collection on campus, with the help of approximately 20 undergraduate students. The researchers make observations as the trees begin to wake up and feed the data into a computer model that incorporates weather forecasts to predict peak bloom.

Historically, the onset of peak bloom has fallen between March 12 and April 3, with an average date of March 23. While the weather impacts peak bloom year to year, climate change drives longer term trends over multiple decades.

Research shows that bloom time has shifted approximately two days earlier each decade since the 1960s. Researchers began monitoring the trees in 2012 and referenced newspaper archives to estimate peak bloom dates for the preceding years.

“With the climate warming more rapidly in the spring, I expected to see the flowers blooming earlier,” said lead author , a recent doctoral graduate from the UW school of environmental and forest sciences. “But as we dove into the literature and examined the data, we saw a delay in bloom, as a result of winter warming in Seattle.”

The study focused on the Somei-yoshino, or Yoshino, cherry tree cultivar. These trees, sometimes called the Japanese flowering cherry, are found throughout Japan. They also line the National Mall in Washington D.C. and paint many Seattle neighborhoods pink in the springtime.

The bloom delay Maust observed applies only to Yoshino cherry trees in Seattle. In colder climates, such as Washington D.C., the trees have ample time to accrue chilling units. Still, the two populations are quite similar, genetically.

Propagation, or breeding more trees, occurs by grafting one tree onto another. This process limits genetic variability in favor of consistency. Because all Yoshino cherry trees are sterile clones of one another, they do not produce fruits or seeds, but they do reliably bloom in beautiful pink hues each spring.

For more information on bloom time, contact Theil at mtheil@uw.edu or Maust at  amaust@uw.edu. For information about the Yoshino Genome Project, contact Steinbrenner at astein10@uw.edu.

At the ����Ӱ�Ӵ�ý Harris Hydraulics Lab, an odd scene plays out. Over and over again, researchers from the UW and the (PNNL) pass a small rubber model of a marine animal through a large tank filled with flowing water and fitted with a spinning turbine. On some runs, the model bonks against the turbine blades; on others, it receives a glancing blow or sails past undisturbed. When bonks or knicks occur, a small collision sensor on one of the turbine’s blades detects the impacts and plots the interactions in a computer program.

The researchers are repeatedly simulating something that they hope will rarely happen in the wild: a collision between marine wildlife like a seabird, seal, fish or whale — or submerged debris like logs — and an underwater turbine.��

“We want to make sure we’re minimizing the chances of a collision in the first place,” said Aidan Hunt, a senior research engineer in mechanical engineering at the UW and member of the (PMEC). “But if a collision were to occur, we want to be able to detect it, and potentially avoid it, in real time. The available evidence suggests that collisions are rare, but we’re taking a ‘trust-but-verify’ approach.”

Marine energy — power harvested from tides, waves and currents — has enormous potential as a clean, renewable resource. But more information is needed about how large, commercial installations of underwater turbines or power-generating buoys could affect marine wildlife, whether through increased noise in the environment, habitat change or direct interactions with equipment.��

The marine collision experiments are part of the , a collection of projects led by PNNL to study the environmental impact of marine energy.��

The work at Harris Hydraulics follows a by PNNL and the UW Applied Physics Lab using a four-foot-tall prototype turbine installed at the entrance to Sequim Bay. In that study, researchers trained an underwater camera on the turbine for 109 days and then catalogued every instance of an animal approaching or interacting with the turbine. The camera captured more than 1,000 instances of fish, birds and seals approaching the turbine blades. There were only four collisions, and all were small fish.��

“This study was a first step, but a promising one,” said co-author , a research scientist at the UW Applied Physics Lab. “We didn’t see any endangered species in our study, and the risk of collision for seals and sea birds seemed to be quite low. We’re excited to get back out there with the camera and learn even more.”

The Sequim Bay experiment generated hours of valuable data, but that degree of intense monitoring may not be practical in large commercial installations in the future. Cheaper impact sensors, like the ones logging bath toy impacts at Harris Hydraulics, could be a solution, researchers say.�� 

The project is funded by the U.S. Department of Energy’s Hydropower & Hydrokinetics Office, through the Pacific Northwest National Laboratory’s Triton Initiative and the TEAMER program.

For more information, contact Hunt at ahunt94@uw.edu or Emma Cotter at emma.cotter@pnnl.gov.

As climate change nudges weather in the eastern Cascades in extreme and volatile directions, forest managers in the region have a lot to juggle. Hotter, drier summers are contributing to bigger and more frequent wildfires. Meanwhile, warmer winters may cause the Cascades to lose 50% of its annual snowpack over the next 70 years. Mountain snow supplies the Yakima River Basin with 75% of its water supply, making it a crucial reservoir for both nature and agriculture . Less winter snow also leads to drier and more fire-prone forests in the summer.

To encourage fire resilience, forest managers use tried-and-true tools like controlled burning and the selective felling of trees to thin out the forest. Both methods remove fuel and help return forests to historical conditions — but less is known about their impact on snowpack.

To address this knowledge gap, a team of researchers at the ����Ӱ�Ӵ�ý and The Nature Conservancy (TNC) embarked on an ambitious, multiyear study of snowpack along Cle Elum Ridge, an area of the eastern Cascades in the headwaters of the Yakima River Basin. The group experimentally thinned the forest to varying degrees in a roughly 150-acre area. Then, they measured the amount and duration of snowpack during the winter of 2023 and compared it to a previous winter before the forest treatment.��

The results were encouraging: Forest thinning efforts increased snowpack by 30% on north-facing slopes and by 16% on south-facing slopes. Thinning aided snowpack the most where it created a patchwork of gaps in the forest rather than a more even density; gaps of 4-16 meters in diameter seemed to be the “sweet spot” for snow.��

The research points toward more refined forest management practices that can optimize for both wildfire resilience and snowpack.

in Frontiers in Forest and Global Change.

“At its core, this research shows that reducing wildfire risk and protecting water resources don’t have to be competing goals,” said lead author , a postdoctoral researcher at the University of Alaska who completed this work as a UW doctoral student of civil and environmental engineering. “That’s genuinely good news for a place facing both growing wildfire threats and increasing water vulnerability. So much of the climate conversation focuses on loss, which makes findings like this especially meaningful.”

Predicting snowpack in forested areas, especially those at higher altitudes, hinges on understanding how much snow reaches the ground and how much lands in the forest canopy. Snow on the ground is more likely to stick around through the season, whereas snow in the trees may either melt or sublimate back into water vapor. In either case, it wouldn’t add to the reservoir of water that melts in the spring and summer.�� 

“Trees intercept snow and so can reduce snowpack, but trees also shade snow and so can retain snowpack,” said senior author , a UW professor of civil and environmental engineering. “The dominant effect depends on winter temperatures, and the Cascade crest near Cle Elum is right on the border where the effect flips from trees decreasing snow to trees saving snow.” 

found that natural gaps in the forests of the eastern Cascades accumulated more snow. This, combined with other research, gave the team reason to hope for a positive connection between forest thinning and snowpack, though it wasn’t a sure thing. have found that open areas elsewhere in the Western U.S. saw reduced snowpack.

Thus, it was time for a direct — and complex — study of managed forests.

Researchers picked Cle Elum Ridge for the work, where TNC’s forest managers were planning thinning treatments to improve forest health and wildfire resiliency. The orientation of the ridge allowed them to compare north- and south-facing slopes — southern slopes in the region see more sunshine and less snow retention on average. From October 2021 to September 2022, the researchers worked with TNC’s forest managers and local contract loggers to remove trees on both slopes in a gradient, from no thinning to extensive. The team also set up time-lapse cameras at several strategic points to measure snow depth over time.

Then, they waited for snow to fall.

By March 2023, the area was close to its peak snowpack, and the team returned with staff and equipment from the UW (RAPID). The RAPID crew flew a specialized drone that generated a detailed 3D map of the study area using a laser-mapping technology called lidar.��

By comparing the new 3D map and timelapse imagery to lidar data captured before the forest treatment, the team was finally ready to calculate two things: the change to the forest structure, and its effect on the snowpack.

Across the whole study area, the team found that thinning helped the forest recover 12.3 acre-feet (or about four million gallons) of water in the form of snow per 100 acres on north-facing slopes, and 5.1 acre-feet (or about 1.5 million gallons) per 100 acres on south-facing slopes.��

As expected, areas where the thinning opened gaps in the canopy were most effective at restoring snow storage that had been previously lost to environmental degradation and climate change. Gaps of 4-16 meters in diameter seemed to retain the most snow, though there were few gaps larger than 16 meters to evaluate.

One surprising result: The way forest managers thin forests doesn’t reliably create gaps. Forest managers map out their reductions using the density of trunks in an area, not canopies, as their primary measurement.

“Imagine a group of 100 people all holding umbrellas in the rain,” said co-author , director of the UW Climate Impacts Group. “They’re standing close enough together that their umbrellas overlap, so none of the rain hits the ground. If you remove 10 of the umbrellas randomly, you’d still have plenty of coverage overall. But, if you remove 10 umbrellas that are right next to one another, you create a gap in the umbrella ‘canopy,’ and you get a 10% increase in the amount of rain that hits the ground.”

That realization adds a nuance to the findings. It’s likely that forest thinning can benefit both wildfire and snowpack resilience at the same time, but only if managers keep canopy gaps in mind.��

“One thing we all learned was that snow people and tree people speak different languages,” Lumbrazo said. “Different experts look at totally different variables to help them decide whether or not to cut down a single tree. So an important goal is to get everyone speaking the same language. And I think this paper is one step towards better communication.”

Overall, the results suggest practical changes to forest management practices in the eastern Cascades. For example, managers might consider more tree-thinning on north-facing slopes, since snowpack gains may be greater there. With further research, these learnings may also extend to other regions in the Pacific Northwest.��

The work could also aid collaboration between forest managers and hydrologists at a time when the region needs all the water it can get.

“As we lose snowpack, everything becomes really squeezed,” said co-author , a senior aquatic ecologist at TNC who earned her doctorate in aquatic and fishery sciences at the UW. “We are currently in our third consecutive year of water restrictions in the Yakima River Basin, and are staring down one of the lowest snow years on record. However, our research shows that the treatments currently used for restoring fire resilient forests are compatible with the forest structure needed for supporting water security. And in a world where climate change is reducing water supplies and increasing wildfire severity, we are pleased to report that the same forest treatments can support both goals.”

Co-authors include , a former UW graduate student of civil and environmental engineering; , a former UW undergraduate student of atmospheric and climate science; , a data processing specialist at the UW RAPID facility; and , director of Forest Conservation and Management at The Nature Conservancy.

This research was funded by The Washington Department of Natural Resources, The Nature Conservancy and the National Science Foundation.��

For more information, contact Lundquist at jdlund@uw.edu, Dickerson-Lange at dickers@uw.edu or Howe at emily.howe@tnc.org.��

The Cascadia Subduction Zone is unusually quiet for a megathrust fault. Spanning more than 600 miles from Canada to California, the fault marks the convergence of the Juan de Fuca and North American plates. While other subduction zones produce sporadic rumblings as the plates scrape past each other, Cascadia , fueling assumptions that the plates are locked together by friction.

The subduction zone — miles offshore and deep underwater — is difficult to observe. Most data collection is based onshore, which limits the breadth and quality of results. The lack of earthquakes further complicates efforts to understand its behavior and structure.

In a new study, the first to monitor strain offshore for an extended period of time, ����Ӱ�Ӵ�ý researchers report that the plates may not be fully locked. Based on 13 years of ground motion data from sensors in different regions, the study shows the northern portion of the fault is locked and quiet, but the central region appears to be more active. There, researchers observed signs of a shallow, slow-motion earthquake and detected pulses of fluid flowing through subterranean channels, which may relieve pressure from the fault.

The findings, , may alter expectations of how this area will respond to a large earthquake. Similar features in other places have stopped a rupture that might have otherwise continued along the entire fault line.

“It’s preliminary, but we think that variable fluid pathways in Cascadia will change the behavior of large earthquakes on the fault,” said co-author , a UW associate professor of Earth and space science.

The Juan de Fuca plate is advancing toward the North American plate at a rate of . But because the plates are stuck together, that motion generates pressure. Eventually, the building tension will exceed what the plates can tolerate. When they eventually slip free, an earthquake will spread along the boundary.

Megathrust earthquakes, which occur at boundaries where one plate slides beneath another, rock the Pacific Northwest every 500 or so years. one to 1700, and estimates suggest a 10 to 15% chance that the entire fault will rupture, producing an earthquake that could exceed magnitude 9, within the next fifty years. The results from this study do not alter those odds, but the dynamics captured might influence the severity of the eventual earthquake.

A recent survey of the seafloor found that into at least four geologically distinct segments. Each one may be insulated from a rupture in another region. In this study, the researchers took a closer look at two of the regions by analyzing data from three monitoring stations, one near Vancouver Island and two off the coast of Oregon.

“We wanted to understand strain changes in different regions offshore,” said lead author , a UW doctoral student of oceanography. “We used the seismometers to measure how the seismic velocity varies underneath each station.”

Seismic velocity is a term used to describe the rate at which ambient noise travels through a material. Because the speed of sound depends on what it is moving through, tracking seismic velocity can give researchers a window into processes occurring beneath the ocean floor.

“When you compact something, you can expect the sound waves to move through it faster,” said Kidiwela.

The steady increase in seismic velocity observed at the northern site told the researchers the rock was compacting, which supports the theory that the two plates are locked in place.

The central region displayed a different pattern. For two months in 2016, seismic velocity decreased. The researchers attribute this drop to a slow-motion earthquake on the shallow edge of the oceanic plate that relieved some of the pressure at the fault.

Other drops in seismic velocity, recorded between 2017 and 2022, were linked to fluid dynamics. Subduction squeezes liquid out of rocks and pushes it toward the surface. The study found that other faults, running perpendicular to the subduction zone, may act as pathways for letting trapped fluid out.

“During a megathrust rupture, one of the ways that an earthquake propagates is through fluid pressure. If you have a way to release these fluids, it could help improve the stability of the fault, and potentially impact how the region behaves during a large earthquake,” Kidiwela said.

Pulling data from just three sites, the researchers observed complex dynamics that may have gone overlooked. Future work will greatly expand this effort. in 2023 to build an underwater observatory in the Cascadia Subduction Zone.

“Finding this link between fluids coming to the shallow subduction zone is pretty unique, as is the evidence that the fault is not completely locked,” said co-author , a UW professor of oceanography and one of the scientists involved with the observatory. “It suggests that we need more instruments there, because there may be more going on than people have been able to figure out before.”

Additional co-authors include from the University of Utah.��

This study was funded by the Jerome M. Paros Endowed Chair in Sensor Networks at the ����Ӱ�Ӵ�ý and the National Science Foundation.��

For more information, contact Kidiwela at seismic@uw.edu.