OREGON STATE UNIVERSITY

college of forestry

Scientists release predatory flies to protect eastern hemlocks from insect attack

CORVALLIS, Ore. – Scientists say that a West Coast fly no bigger than a grain of rice may hold the key to survival of a tree that is being devastated by an invasive insect.

The eastern hemlock grows from the Carolinas to Quebec and is threatened by the hemlock woolly adelgid, which is native to Asia and the Pacific Northwest. Through nearly a decade of research, scientists at Oregon State University and the USDA Forest Service have identified a predatory fly that kills the adelgid and may help to curb infestations.

In the southern Appalachians, hemlocks have been particularly hard hit, including a less-abundant species known as Carolina hemlock. As much as 80 to 90 percent of the mature trees in some stands have been killed. Researchers believe that without intervention, they could suffer the same fate as the American chestnut – a once-common eastern tree that was nearly wiped out by a fungal disease in the early 1900s.

A research team led by two entomologists – Darrell Ross in the Oregon State College of Forestry and Kimberly Wallin with the University of Vermont and the USDA Forest Service Northern Research Station – demonstrated that a type of fly in the Pacific Northwest known as a silver fly (species in the genus Leucopis) attacks adelgids on western and eastern hemlocks. And while silver flies in the East are known to prey on a species of adelgids in pine trees, those flies are not known to be attracted to hemlocks.

“Populations of flies in the West search for hemlock trees, and that’s where they find their hosts,” said Ross. “The same species in the East has evolved to look for pine trees. They probably use chemical cues from those trees to find their habitat and their hosts. That’s why it’s useful to take the flies from out here, because they’ll look for hemlock trees and feed on the hemlock woolly adelgid in the East.”

This past spring, scientists with the USDA Forest Service, the University of Vermont and Cornell University released silver flies from the Pacific Northwest in hemlock stands near Grandview, Tennessee, and along the shore of Skaneateles Lake in New York state. The researchers are monitoring the trees for evidence that the flies can successfully reproduce and prey on hemlock woolly adelgids. Early results indicate that the flies are mating, laying eggs and producing larvae that are growing to the adult stage.

“That is as good as we could have hoped for at this point,” said Ross. “It remains to be seen whether they will survive and if their populations will grow to densities that significantly impact the hemlock woolly adelgid populations and, ultimately, the survival of eastern hemlocks. We probably won't have answers to those questions for a year or two.”

“We don’t hope that the flies will eradicate all the adelgids,” added Wallin, but if they could provide a check on the pest’s population size and territorial expansion, it could allow some hemlocks to persist and recover.

The releases were done under a permit from the Animal Plant Health Inspection Service (APHIS). Forest Service scientist Albert “Bud” Mayfield and Extension researcher Mark Whitmore of Cornell led the release effort in Tennessee and New York respectively.

“It’s been a decade’s worth of research, first identifying the flies and then looking at their host breadth and then seeing if they would feed on the eastern hemlock woolly adelgid,” said Ross. “Now it’s a matter of waiting and seeing if they significantly contribute to controlling adelgid populations.”

In the West, adelgids and the silver flies that feed on them are difficult to find in the forest. “Where we find them is on street trees and in peoples’ yards and city parks,” said Ross. The Oregon State scientist travels to Washington state to collect silver flies on western hemlocks. He sends boxes of infested branches to Nathan Havill, a Forest Service entomologist in Hamden, Connecticut. In Havill’s lab, research technician Arielle Arsenault rears, collects and sorts the insects in growth chambers before they are released into the wild.

Although some species of adelgids are native to North America and do not pose a threat, the hemlock woolly adelgid currently present in the eastern United States is from East Asia. In the late 1970s, as infestations in Appalachian hemlock stands grew increasingly severe, scientists were unsure about the insect’s origins. In the early 2000s, Havill used genetic techniques to demonstrate that it had been introduced from southern Japan to the vicinity of Richmond, Virginia, in the 1950s.

He also showed that it is native to the Pacific Northwest. There, the insects appear to be controlled by silver flies and possibly by other predators as well.

Other researchers contributing to the project are Ross’ former OSU graduate students Glenn R. Kohler and Sarah M. Grubin. They received assistance from a leading taxonomic expert in silver flies, Stephen D. Gaimari of the California Department of Food and Agriculture. Their reports have appeared in Environmental Entomology and other professional journals.

Funding for the research was provided by the Hemlock Woolly Adelgid Initiative of the USDA Forest Service.

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Darrell Ross, 541-737-6566; Kimberly Wallin, 802-656-2517

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Kimberly Wallin
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Hemlock woolly adelgids on a hemlock branch
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Silver fly larvae feed on adelgid eggs

Global decline of large herbivores may lead to an “empty landscape,” scientists say

CORVALLIS, Ore. – The decline of the world’s large herbivores, especially in Africa and parts of Asia, is raising the specter of an “empty landscape” in some of the most diverse ecosystems on the planet, according to a newly published study.

Many populations of animals such as rhinoceroses, zebras, camels, elephants and tapirs are diminishing or threatened with extinction in grasslands, savannahs, deserts and forests, scientists say.

An international team of wildlife ecologists led by William Ripple, Oregon State University distinguished professor in the College of Forestry, conducted a comprehensive analysis of data on the world’s largest herbivores (more than 100 kilograms, or 220 pounds, on average), including endangerment status, key threats and ecological consequences of population decline. They published their observations today in Science Advances, the open-access online journal of Science magazine.

The authors focused on 74 large herbivore species – animals that subsist on vegetation – and concluded that “without radical intervention, large herbivores (and many smaller ones) will continue to disappear from numerous regions with enormous ecological, social, and economic costs.” Ripple initiated the study after conducting a global analysis of large-carnivore decline, which goes hand-in-hand, he said, with the loss of their herbivore prey.

“I expected that habitat change would be the main factor causing the endangerment of large herbivores,” Ripple said. “But surprisingly, the results show that the two main factors in herbivore declines are hunting by humans and habitat change. They are twin threats.”

The scientists refer to an analysis of the decline of animals in tropical forests published in the journal BioScience in 1992. The author, Kent H. Redford, then a post-doctoral researcher at the University of Florida, first used the term “empty forest.” While soaring trees and other vegetation may exist, he wrote, the loss of forest fauna posed a long-term threat to those ecosystems. 

Ripple and his colleagues went a step further. “Our analysis shows that it goes well beyond forest landscapes," he said, “to savannahs and grasslands and deserts. So we coin a new term, the empty landscape.” As a group, terrestrial herbivores encompass about 4,000 known species and live in many types of ecosystems on every continent except Antarctica.

The highest numbers of threatened large herbivores live in developing countries, especially Southeast Asia, India and Africa, the scientists report. Only one endangered large herbivore lives in Europe (the European bison), and none are in North America, which, the authors add, has “already lost most of its large mammals” through prehistoric hunting and habitat changes.

The authors note that 25 of the largest wild herbivores now occupy an average of only 19 percent of their historical ranges. Competition from livestock production, which has tripled globally since 1980, has reduced herbivore access to land, forage and water and raised disease transmission risks, they add.

Meanwhile, herbivore hunting occurs for two major purposes, the authors note: meat consumption and the global trade in animal parts. An estimated 1 billion humans subsist on wild meat, they write.

“The market for medicinal uses can be very strong for some body parts, such as rhino horn,” said Ripple. “Horn sells for more by weight than gold, diamonds or cocaine.” Africa’s western black rhinoceros was declared extinct in 2011.

Co-author Taal Levi, an assistant professor in Oregon State’s Department of Fisheries and Wildlife, said the causes of the decline of some large herbivores “are difficult to remedy in a world with increasing human populations and consumption.”

“But it's inconceivable that we allow demand for horns and tusks to drive the extirpation of large herbivores from otherwise suitable habitat,” Levi said. “We need to intensify the reduction of demand for such items.”

The loss of large herbivores suggests that other parts of wild ecosystems will diminish, the authors write. The likely consequences include: reduction in food for large carnivores such as lions and tigers; diminished seed dispersal for plants; more frequent and intense wildfires; slower cycling of nutrients from vegetation to the soil; changes in habitat for smaller animals including fish, birds and amphibians.

“We hope this report increases appreciation for the importance of large herbivores in these ecosystems,” said Ripple. “And we hope that policymakers take action to conserve these species.”

To understand the consequences of large herbivore decline, the authors call for a coordinated research effort focusing on threatened species in developing countries. In addition, solutions to the decline of large herbivores need to involve local people. “It is essential that local people be involved in and benefit from the management of protected areas,” they write. “Local community participation in the management of protected areas is highly correlated with protected area policy compliance.”

In addition to Ripple and Levi, co-authors include Christopher Wolf and Luke Painter of Oregon State; Rodolfo Dirzo of Stanford University; Thomas M. Newsome of The University of Sydney in Australia; Kristoffer T. Everatt and Graham I.H. Kerley of Nelson Mandela University in South Africa; Mauro Galetti of the Universisade Estadual Paulista in Brazil; Matt W. Hayward of Nelson Mandela University and Bangor University in the United Kingdom; Peter A. Lindsey of Panthera (nonprofit organization) and the University of Pretoria in South Africa; David W. MacDonald, Yadvinder Malhi and Christopher J. Sandom of the University of Oxford in the United Kingdom; John Terborgh of Duke University; Blaire Van Valkenburgh of UCLA.

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William Ripple, 541-737-3056

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Eastern gorilla by Peter Stoel
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African elephant by Kristopher Everatt
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Lowland tapir by Thomas Newsome
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Mountain Nyala by Halszka Hrabar
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The threatened European bison, Bison bonasus. Photo by Graham Kerley.
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 Common hippopotamus by Kristopher Everatt
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Illustration of herbivore impacts

Cascades study may rewrite the textbook on forest growth and death

CORVALLIS, Ore. – A century-long study in the Oregon Cascades may cause scientists to revise the textbook on how forests grow and die, accumulate biomass and store carbon.

In a new analysis of forest succession in three Douglas-fir stands in the Willamette National Forest, two Oregon State University scientists report that biomass – a measure of tree volume – has been steadily accumulating for 150 years. In the long term, such a trend is not sustainable, they said, and if these stands behave in a manner similar to others in the Cascades, trees will begin to die from causes such as insect outbreaks, windstorms or fire.

“Mortality will occur in the future,” said Mark Harmon, professor and Richardson Chair in Forest Science at OSU. “It just hasn’t arrived.”

In 1910, pioneering forest scientist Thornton T. Munger established the research plots in stands that had, by that time, been recovering from a wildfire for about 50 years. Growth and mortality were measured in the plots every five years until 1955 and again starting in 1992.

Scientists generally treat mortality as a phenomenon that occurs at an average rate over many years, said Harmon. However, results from these stands show that mortality can proceed slowly for many years and then increase rapidly in sudden pulses.

Harmon and Rob Pabst, forestry research assistant at OSU, published their findings recently in the Journal of Vegetation Science.

“The way we have thought about mortality is wrong,” said Harmon, who is conducting long-term monitoring at 10 stands in the Cascades. “When we started measuring mortality, our goal was to come up with a long-term average, but it became clear that that’s misleading because its very nature is variable.”

After a disturbance such as a fire or a clear-cut harvest, “it takes a while for the machinery in the forest to get going,” Harmon said. “And then it starts to increase biomass and hits a point where a lot of the biomass isn’t being removed by tree death. But we know there are episodes of mortality: beetle kills, fire, wind storms.”

Continuous accumulation of biomass over many centuries is not realistic, he added. If the tree stands they analyzed were to continue to accumulate biomass over the next 200 years, they wrote, biomass would reach world-record levels, far exceeding “what has been observed in old-growth forests of the Pacific Northwest.”

“There must be some event waiting in the future that will knock them down,” Harmon said. “Whether that will become more frequent in the future because of climate change or something else, I don’t know.”

The findings have practical implications for management of public and private forestlands. For timber production purposes, it has been common practice to harvest trees at regular intervals, usually when the rate of biomass accumulation reaches a high point. In Douglas-fir forests, that interval is often 50 to 70 years.

However, since the stands in Harmon and Pabst’s study have continued to accumulate biomass steadily for 150 years, the optimum harvest cycle may be considerably longer than 50 years. It is likely, they wrote, that some Douglas-fir forests have been harvested many decades before they reached a point when the rate of biomass accumulation slowed.

The findings also suggest that these forests can continue to sequester carbon from the atmosphere well past typical harvest intervals. “While we suspect that live biomass accumulation will eventually slow down and perhaps cease, this is likely to occur many decades in the future, barring a major disturbance in these plots,” they wrote. “This implies substantially more live carbon can be accumulated in this type of forest if harvest rotations are extended past the 50- to 100-year age.”

The research was supported by the National Science Foundation and the Pacific Northwest Research Station of the USDA Forest Service. The paper is available online (http://onlinelibrary.wiley.com/doi/10.1111/jvs.12273/full).

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Mark Harmon, 541-737-8455

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Pioneering forest scientist T. T. Munger established long-term monitoring stands in the Oregon Cascades in 1910.

Satellites give scientists unprecedented views of insect outbreaks in forests

CORVALLIS, Ore. – Scientists for the first time have simultaneously compared widespread impacts from two of the most common forest insects in the West – mountain pine beetle and western spruce budworm – an advance that could lead to more effective management policies.

By combining data from satellites, airplanes and ground-based crews, the researchers have shown in unprecedented detail how insects affect Western forests over decades.

In the past, forest managers relied on airplane surveys to evaluate insect damage over broad areas. However, satellites can reveal patterns at a much finer scale. By combining both types of data, scientists are refining estimates of damage and showing how they may relate to other factors that determine forest structure and composition.

“This is the first time anyone has compared the impacts from these two insects in consistent units of change going all the way back to 1970,” said Garrett Meigs, a post-doctoral researcher at the University of Vermont. Meigs conducted his analysis while he was a Ph.D. student in the College of Forestry at Oregon State University. He worked with Robert Kennedy, an expert in landscape analysis and an assistant professor in OSU’s College of Earth, Ocean, and Atmospheric Sciences.

They published their findings in this week’s issue of Forest Ecology and Management, a professional journal.

Outbreaks of both insects occur in cycles and can affect millions of acres of forest lands from year to year. The mountain pine beetle has killed lodgepole pine trees across much of western Canada and the United States in recent decades. Western spruce budworm defoliates – but does not normally kill – Douglas-fir, spruce and true firs. However, repeated years of western spruce budworm attack can weaken trees and make them vulnerable to other stresses, which may eventually kill them.

“Mortality from bark beetles is only the beginning of long-term change,” said Helen Maffei, a U.S. Forest Service scientist in Bend, Oregon, who supported the study. “Dead trees fall and decay, and forest regrowth begins and continues over many decades. This new technique can help us understand not only how insect outbreaks are initiated and spread but also address the question, ‘What comes next’? It can help us better understand the process of recovery.”

The new method of using satellites, aerial surveys and forest inventory data enables scientists to identify hotspots of insect activity that may need special attention from forest managers in the future.

“By blending the richness of the Forest Service data with the robustness of the satellite signal, I think we have a really useful new approach to understanding insect patterns on the landscape,” said Kennedy.

The new methods aren’t yet available to businesses, government agencies and other organizations, but through a partnership between Oregon State and Google, that may change. Kennedy is working with the company to use satellite data and new analytical procedures in a system that would be accessible to land managers. The system will be freely available on Google’s Earth Engine, a platform for planetary data and analysis.

“If successful, it would mean that agencies could begin working with the satellite data and potentially take the next step in merging with the Forest Service observation data directly,” said Kennedy.

The report is online in OSU’s Scholar’s Archive, http://hdl.handle.net/1957/55196. Support was provided by the NASA Earth and Space Science Fellowship Program and the USDA Forest Service.

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Garrett Meigs, 541-602-8167

Robert Kennedy, 541-737-6332

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Mountain pine beetle larvae borrow under bark.

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Mountain pine beetle damaged forests in the Oregon Cascades.

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Trees defoliated by western spruce budworm in Washington.

OSU’s Starker Lecture Series to focus on Douglas-fir

CORVALLIS, Ore. – Oregon State University’s annual Starker Lecture Series will focus this year on the Pacific Northwest’s most iconic tree – the Douglas-fir – which had its first major planting 100 years ago.

The series is hosted by the OSU College of Forestry. It kicks off on Thursday, Jan. 29, with a screening of the documentary, “Finding David Douglas.”

The film, which looks at the 19th-century Scottish botanist’s compelling life of adventure and discovery, begins at 7 p.m. at the Whiteside Theatre in Corvallis, located at 361 S.W. Madison Ave. Director and historian Lois Leonard will be on hand for a discussion with the audience after the film. The event is free and open to the public.

On Thursday, Feb. 5, a workshop will be held on “Objectives-Driven Silviculture” at the Linn County Expo Center, located at 3700 Knox Butte Rd. in Albany. The workshop is sponsored by the Mary’s Peak Chapter of the Society of American Foresters.

Free public lectures in the series include:

  • Feb. 12 - “Every Reason to Hope: David Douglas and Pacific Northwest Trees,” by Jack Nisbet, author of a book on the botanist titled “David Douglas: The Collector and Naturalist at Work.” 3 p.m. Richardson Hall Room 107. A book signing will follow. OSU professor emeritus Richard Hermann will sign copies of a new book, “Douglas-fir: The Genus Pseudotsuga,” which he co-authored with OSU professor emeritus Denis Lavender.
  • March 12 – “A Contemporary View of Douglas-fir Silviculture,” by Chad Oliver, the Pinchot Professor of Forestry and Environment and director of the Global Institute of Sustainable Forests. 3:30 p.m. Richardson Hall Room 107.
  • April 16 – “Innovative Applications of Douglas-fir in Building Design,” by Ethan Martin, Northwest regional director of WoodWorks, an initiative of the Wood Products Council. 3:30 p.m. Richardson Hall Room 107.

On Thursday, May 14, the series will conclude with a capstone field trip where participants will tour managed forests, a wood products research and testing lab, and a commercial processing facility, as well as learn about new architectural uses for wood.

The Starker Lecture Series is sponsored by the Starker family in memory of T.J. and Bruce Starker, prominent leaders in the development of the Oregon forest products industry. The series is also supported by the OSU College of Forestry and the Oregon Forest Resources Institute.

More information on the series is available at http://starkerlectures.forestry.oregonstate.edu

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OSU College of Forestry, 541-737-2004

H.J. Andrews research forest federal funding renewed

CORVALLIS, Ore. – Research and education at the H.J. Andrews Experimental Forest, one of the nation’s premier ecological science sites, has received a six-year, $6.7 million grant from the National Science Foundation.

Funds will support a new round of projects through the Long-Term Ecological Research program at the 16,000-acre Andrews forest in the Cascades east of Eugene. Since 1980, the Andrews forest has been the site of groundbreaking forest research and educational programs that serve more than 1,500 children and adults annually.

Oregon State University, the USDA Forest Service's Pacific Northwest Research Station and the Willamette National Forest collaborate in ecological research and application to critical resource management issues such as restoration of aquatic ecosystems, managing carbon stocks and adaptation to climate change..

The goal of the latest round of funding, known as LTER7, is to examine how forested mountain ecosystems respond to changes in climate and land-use and how people interact with the forest through ethical decision-making, said Michael Paul Nelson, the Ruth H. Spaniol chair of renewable resources at OSU and lead principal investigator for the H.J. Andrews Experimental Forest LTER research program.

It is focused on a central question: How do climate, natural disturbance and land use as controlled by forest governance – the structures and processes through which people make decisions and share power – interact with biodiversity, hydrology and carbon and nutrient dynamics?

Researchers will continue to address issues such as the transport of carbon and other nutrients through air and water flows. They will study the decomposition of organic matter and changes in the timing of events such as the blossoming of plants and insect emergence from streams.

“Many aspects of LTER7 will have broader social impacts,” Nelson said. “We will continue the strong tradition of fostering public engagement and producing policy-relevant knowledge in the area of ecosystem science. We’re engaging the public, resource managers and policymakers in studies of how changing social networks influence forest landscapes. We’ll also analyze forest governance from the perspective of conservation ethics.”

Tight federal budgets made this a demanding funding year for all 26 of the locations in the Long-Term Ecological Research Network, he said. Support for the Andrews program reflects an innovative combination of physical and social science activities.

Education and outreach projects include a rich K-12 teacher-training program and a strong arts and humanities effort through the Long-Term Ecological Reflections program, which includes partnering with the Spring Creek Project for Ideas, Nature, and the Written Word at Oregon State.

The National Science Foundation’s review panel praised the partnership between Oregon State and the Forest Service. “It could be a model for other collaborative research groups with diverse requirements,” reviewers noted.

“The Andrews forest has offered exceptional opportunities for students and faculty, not just from OSU, but other schools and colleges, to be part of relevant, impactful research on our forest landscapes,” said Thomas Maness, dean of OSU’s College of Forestry, which houses the Andrews LTER program.

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Michael Paul Nelson, 541-737-9221

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The H.J. Andrews Experimental Forest

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Lookout Creek in the H.J. Andrews Experimental Forest

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Old-growth habitat at the H.J. Andrews Experimental Forest

Former OSU forestry dean Hal Salwasser dies at 69

CORVALLIS, Ore. – Harold J. “Hal” Salwasser, former dean of the College of Forestry at Oregon State University, died at his home in Corvallis Wednesday night (Oct. 15) of apparent natural causes. He was 69 years old.

Salwasser had been an active member of the forestry faculty since stepping down as dean in 2012 after 12 years leading the college. He had planned to retire from Oregon State at the end of December.

“Hal was a wonderful colleague, a respected forester and an engaged Corvallis community member,” said OSU President Edward J. Ray. “His work leading the College of Forestry grew the university’s essential contributions in teaching and research concerning the world’s forests, watersheds, natural areas and the wood products industry.”

Salwasser guided the OSU College of Forestry through a period of immense transition in forest policies and management nationally and globally. He led efforts to maintain forest production while incorporating new concerns about biodiversity, climate change, wildfire, stream health protection, and other issues.

As dean, Salwasser oversaw a forestry program that is more than 120 years old and is consistently ranked as one of the best forestry programs in the country. Today the OSU College of Forestry has an annual budget of some $25 million, with more than a thousand undergraduate and graduate students and an internationally recognized faculty.

Salwasser also directed the Forest Research Laboratory at OSU, which spans a broad range of disciplines, while incorporating social, economic and policy aspects of forests.

Before coming to Oregon State, Salwasser was the chief executive officer of the Pacific Southwest Research Station of the U.S. Forest Service. There he supervised the natural resources research and development of Forest Service activities in California, Hawaii and the Pacific Islands. He previously was regional forester for the northern region of the U.S. Forest Service, which included Idaho, Montana, and the Dakotas.

The Salwasser family has requested that in lieu of flowers, contributions be made to the Hal Salwasser Fellowship Fund through the OSU Foundation.

Plans for a celebration of life will be announced later.

 

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Steve Clark, 541-737-3808; steve.clark@oregonstate.edu;

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Hal Salwasser

Aspen recovering as wildlife populations shift in Yellowstone National Park

CORVALLIS, Ore. – Wildlife in Yellowstone National Park is undergoing dramatic shifts with consequences that are beginning to return the landscape to conditions not seen in nearly a century, according to a series of new studies.

In the park’s northeast section, elk have decreased in number in their historic winter range in the Lamar Valley and are now more numerous outside the park. This change in elk numbers and distribution can be traced back to the reintroduction of wolves in 1995-96. Scientists have hypothesized that wolves affect both the numbers and the behavior of elk, thereby reducing the impact of browsing on vegetation, a concept known as a “trophic cascade.”

Rising grizzly bear numbers are also taking their toll on elk. As a result, lush vegetation is growing back in many but not all areas.

“Without wolves, this would not have happened,” said Luke Painter, an instructor at Oregon State University and lead author of three recent papers that describe the results of his fieldwork monitoring vegetation growth patterns in the park. “Wolves caused a fundamental change, but certainly they are interacting with other factors such as bears, climate, fire and human activity.”

Bison have also played an important role in the changes in vegetation in northern Yellowstone. Their numbers have increased four-fold as elk have decreased. In places where bison congregate, they browse on aspen, cottonwood and willow, compensating in part for the decline in elk. However, bison cannot reach as high as elk to browse, allowing more trees to escape and grow to maturity.

From 2010-12, hiking in the Yellowstone backcountry, Painter re-measured 87 aspen stands previously studied by his adviser, William Ripple, and former OSU student Eric Larsen in 1997 and 1998. Painter conducted a regional survey of stands across the northern part of the park and also in the Shoshone National Forest west of Yellowstone, where hunting and cattle grazing are allowed.

Painter detailed his findings this summer in an online report in the journal Ecology. He received his Ph.D. in the College of Forestry at Oregon State in 2013 and is now an instructor in OSU’s Department of Fisheries and Wildlife.

“This new study illustrates the powerful insights you can get from taking a view over 15 years or more,” said Aaron Wirsing, an associate professor of wildlife science at the University of Washington. Wirsing was not involved in Painter’s study.

“Wolf reintroduction was a landmark moment, but the changes vary throughout ecosystems as a function of other factors,” Wirsing added. “By taking an ecosystem point of view, this paper shows the complexity of the system and all its moving parts.”

For much of the 20th century, aspen appeared to be in severe decline. While studies by Ripple and his OSU colleague Robert Beschta pointed to the beginnings of an aspen recovery within a decade of wolf reintroduction, other researchers reported finding little evidence of aspen regrowth. Painter has shown that aspen recovery is widespread over much of the northern range, but where elk are still numerous, aspen stands are heavily browsed and stunted. In the famous Lamar Valley itself, bison have become the dominant herbivore, suppressing some aspen stands.

“There is a recovery of aspen happening, but it’s early and it’s not happening everywhere yet,” said Painter. “That’s the way things work in nature.”

Painter found that a quarter of all aspen stands now have five or more young aspen tall enough to escape elk browsing, a condition not seen in decades. Moreover, 46 percent of all stands have at least one tree that has grown beyond the reach of elk. Browsing rates were significantly lower in 2012 than in 1997. The greatest increases in aspen heights were in the east where Ripple and Beschta first reported signs of recovery in 2006.

Other researchers have suggested that fire and climate could be just as significant as wolves in explaining the recovery of aspen stands, but Painter found no evidence to support those possibilities. Following the severe Yellowstone fires in 1988, he said, aspen failed to recover as elk continued to browse young shoots.

In addition, aspen in northern Yellowstone showed signs of vigorous regrowth since 2000 despite relatively dry conditions, which would be likely to suppress aspen growth.

In the early 1990s, many researchers didn’t expect widespread changes to occur from wolf reintroduction, Painter said. “The idea was that if you drop some wolves in here, everything will stay about the same, but the elk population will go down. But what happens is, it mixes up the whole pot. It’s been a surprise that there are so few elk wintering in the Lamar Valley.”

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Luke Painter, 360-970-1164

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Bison in Yellowstone National Park, 2012.

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Luke Painter

New book details threats to the world’s forests, offers solutions for conservation

CORVALLIS, Ore. – As forestlands around the globe continue to diminish in the wake of human population growth and climate change, two leading scientists have written a new book in which they issue a call to action for forest conservation.

Among threats to the vital services provided by forest ecosystems, they say, are residential development, climate change and illegal logging operations in the tropics.

“In the 1950s, we assumed that the forests were not going to change,” said Richard Waring, retired professor of forestry at Oregon State University and co-author of the book. “We assumed that if you disturbed them in a certain way, they would come back. Right now it looks like some of the drier forestlands will be in continuous transition to ecosystems that may not include trees at all.”

Since it is buffered by the Pacific Ocean, the West Coast is relatively unusual. Climate change models show that the conditions there for tree growth are likely to stay the same or even improve.

In the 1980s, Waring said, scientists began to realize that their assumptions of forest stability were wrong. They began incorporating rising atmospheric carbon-dioxide levels into their computer models of forest ecosystems. In a few places, unprecedented insect outbreaks and fires began to occur.

Waring and Joseph Landsberg, a forest biologist in Australia, detail their thoughts in a new book, “Forests in Our Changing World,” published by Island Press.

Managing forests for sustainability, they said, will mean controlling destructive, often unregulated logging operations in the tropics; turning forest slash into the soil rather than burning it; increasing resilience by planting multiple species of trees rather than single species; reducing erosion from forest soils; and monitoring broad forest trends through satellite imagery.

In the United States, Waring said, about 1.5 percent of the nation’s forestlands are disturbed annually through logging, housing development, fires and clearing. While that may not sound like a lot, he added, it means that most of the country’s forests would be replaced with new forests in less than 70 years.

“It’s a wake-up call,” Waring said. “We think it’s real and people should be concerned about it. There’s more carbon stored in the forest than anywhere else above ground.”

Between 2000 and 2005, about 6 percent of the United States’ forestlands were disturbed through fires, insect attacks, disease and logging – the largest percentage of any country with large forested areas. Canada saw the largest area of disturbance, about 40 million acres, in absolute terms. Most human disturbances of forests, Waring and Landsberg wrote, are driven by economic gain that ignores the long-term loss of ecosystem services such as carbon storage, biodiversity and water quality.

Wood products, which can store sequestered carbon, will increasingly come from tree plantations rather than natural forests, they added. At present, plantations account for only 3 percent of the world’s forestlands but produce about 25 percent of all forest products.

Future plantation managers would do well to avoid the “debacle” with blue gum (Eucalyptus globulus) in western Australia. Federal tax incentives and exaggerated claims of tree growth led to overplanting and as drought struck the region, water supplies were depleted, and trees stopped growing or died.

Waring specializes in forest ecology and the analysis of trends through satellite imagery. Landsberg has conducted forest research in the United Kingdom and Australia. As a former chief of the Division of Forest Research for Australia’s Commonwealth Scientific and Industrial Research Organization, or CSIRO, he oversaw a staff of more than 200 scientists.

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Richard Waring, 541-737-6087

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9781610914956

New book details world-wide research on Douglas-fir

CORVALLIS, Ore. — The Pacific Northwest’s iconic Douglas-fir tree rivals coast redwood for honors as the world’s tallest tree. It isn’t a true fir – the species that was named for Scottish botanist David Douglas is, however, the mostly widely distributed North American conifer.

And it is a marvel of water engineering. From root to top, a mature tree transmits water across more than 22,000 cell walls, each equipped with 50 to 60 elegantly designed valves.

In recognition of this commercially important tree, the Forest Research Laboratory at Oregon State University has published “Douglas-fir: The Genus Pseudotsuga,” which details more than a century of research. It covers what is known about the species’ evolutionary history, genetics, environmental requirements and breeding programs in Europe, Asia, Australia, New Zealand and North America.

Douglas-fir is native to western North America but has been accepted in forest management programs around the world. It is a member of the genus Pseudotsuga, which includes up to a dozen species in Asia and North America. In Europe, Douglas-fir is the most commonly planted North American tree.

Two OSU forest scientists, Denis Lavender and Richard Hermann, wrote “Douglas-fir.” Both received Ph.Ds. from Oregon State in botany and went on to conduct research on the species through the OSU Forest Research Lab until they retired.

“When Denis and I were at the Forest Research Lab, we received questions about Douglas-fir from around the world,” said Hermann. “So we decided to collect everything we could find and write a book.”

A native of Germany, Hermann specialized in Douglas-fir management in plantations and natural regeneration. In addition to his work at Oregon State, he held research appointments in Poland, France, Germany and Italy and served in leadership positions with the International Union of Forest Research Organizations.

Lavender, who died last spring, focused on reproductive biochemistry and the role of dormancy in tree vitality. After leaving Oregon State in 1984, he served as the head of the Forest Science Department at the University of British Columbia and helped to establish the Silvicultural Institute of British Columbia. His method for storing and planting seedlings increased the survival rate of conifers by 20 percent.

“Douglas-fir” is available free online at http://hdl.handle.net/1957/47168 or in print for $45 ($60 for international orders) from the communications office in the OSU College of Forestry, forestrycommunications@oregonstate.edu.

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Richard Hermann, 503-223-8307