OREGON STATE UNIVERSITY

college of forestry

Oldest trees are growing faster, storing more carbon as they age

CORVALLIS, Ore. – In a finding that overturns the conventional view that large old trees are unproductive, scientists have determined that for most species, the biggest trees increase their growth rates and sequester more carbon as they age.

In a letter published today in the journal Nature, an international research group reports that 97 percent of 403 tropical and temperate species grow more quickly the older they get. The study was led by Nate L. Stephenson of the U.S. Geological Survey Western Ecological Research Center. Three Oregon State University researchers are co-authors: Mark Harmon and Rob Pabst of the College of Forestry and Duncan Thomas of the College of Agricultural Sciences.

The researchers reviewed records from studies on six continents. Their conclusions are based on repeated measurements of 673,046 individual trees, some going back more than 80 years.

This study would not have been possible, Harmon said, without long-term records of individual tree growth. “It was remarkable how we were able to examine this question on a global level, thanks to the sustained efforts of many programs and individuals.”

Extraordinary growth of some species, such as Australian mountain ash – also known as eucalyptus –  (Eucalyptus regnans), and the coast redwood (Sequoia sempervirens), is not limited to a few species, the researchers said. “Rather, rapid growth in giant trees is the global norm and can exceed 600 kg (1,300 pounds) per year in the largest individuals,” they wrote.

“In human terms, it is as if our growth just keeps accelerating after adolescence, instead of slowing down,” said Stephenson. “By that measure, humans could weigh half a ton by middle age, and well over a ton at retirement.”

The report includes studies from the Pacific Northwest. Harmon and his colleagues worked in forest plots – some created as early as the 1930s – at the H.J. Andrews Experimental Forest east of Eugene and Mount Rainier National Park. Researchers measured growth in Douglas-fir, western hemlock, Sitka spruce, western red cedar and silver fir. The National Science Foundation and the Pacific Northwest Research Station of the USDA Forest Service provided funding.

Under the auspices of the Smithsonian Institution’s Center for Tropical Forest Science, Thomas and colleagues in Africa established a 123-acre forest research site in Cameroon in 1996. They measured growth in about 495 tree species.

“CTFS does very important work facilitating collaboration between forest ecologists worldwide and therefore enabling us to gain a better insight into the growth of trees and forests,” Thomas said. “This model for collaboration was the basis of the Nature study.”

While the finding applies to individual trees, it may not hold true for stands of trees, the authors cautioned. As they age, some trees in a stand will die, resulting in fewer individuals in a given area over time.

The study was a collaboration of 38 scientists from research universities, government agencies and non-governmental organizations in the United States, Panama, Australia, United Kingdom, Germany, Colombia, Argentina, Thailand, Cameroon, Democratic Republic of Congo, France, China, Taiwan, Malaysia, New Zealand and Spain.

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Mark Harmon, 541-737-8455; Duncan Thomas,  541-752-5211

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Photo by Duncan Thomas
Korup canopy
Photo by Duncan Thomas

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Photo by Al Levno

$1 million USDA grant boosts Oregon State tree research for bioenergy

CORVALLIS, Ore. – A $1 million grant to a research team led by Steve Strauss, Oregon State University distinguished professor of forest biotechnology, aims to boost America’s energy independence by helping to develop a tree-based bioenergy industry.

The funds from the U.S. Department of Agriculture will support an investigation into the genetics of fast-growing cottonwood trees. The researchers will focus on the molecular mechanisms of hybrid vigor, which promote growth and productivity. All commercially grown cottonwoods in the Pacific Northwest are hybrids between different species, and it is costly and time-consuming for industries to identify the most productive hybrids.

“The research may enable more rapid development of highly productive and stress-tolerant varieties,” Strauss said.

The research will be carried out in collaboration with Portland-based GreenWood Resources, the major grower of cottonwoods in the Pacific Northwest. Other major scientific collaborators include Stephen DiFazio of West Virginia University and Todd Rosenstiel of Portland State University.

The grant is part of an $8 million national bioenergy initiative supported by the USDA and the U.S. Department of Energy.

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Steven Strauss, 541-737-6578

GMOs in agriculture to be Corvallis Science Pub topic

CORVALLIS, Ore. – Direct modification of DNA, or genetic engineering, is a tool for plant breeding that has spread at unprecedented speed over the last two decades. At the Oct. 14 Corvallis Science Pub, Steve Strauss, director of Oregon State University’s Outreach in Biotechnology program, will discuss the pros and cons of gene technology for agriculture.

The Science Pub presentation begins at 6 p.m. in the Majestic Theater, at 115 S.W. Second St. in Corvallis. It is free and open to the public. In November, Science Pub will resume at its usual location at the Old World Deli.

Today’s agricultural bounty can be traced to traditional plant breeding and other technologies, but population growth and demands for higher quality food will require large improvements in agricultural productivity, said Strauss. The undesirable environmental and social effects of more intense farming systems also need to be minimized.

“Gene technology is a valuable tool, not a silver bullet,” Strauss added. “It can do a lot, but it must be used with due caution and as part of integrated, ecologically-guided management systems for sustained benefit.”

Biotechnology appears capable of providing major humanitarian benefits to the poor by improving nutrition and food security.

“Despite the fears and growing legal barriers, the stakes in this debate are too high to turn away from,” he said. “We must find socially acceptable ways to move forward.”

While genetic engineering can provide nutritional and agronomic benefits, it has also come up against strong social and legal resistance in many countries, making its future uncertain. Strauss will review what the technology actually is, how it is similar and different from conventional breeding, and how it has impacted agriculture to date. He will also discuss diverse sources of the controversy surrounding it, including the numerous myths and confusing science that pervade the online world.

Strauss is a distinguished professor in the Oregon State College of Forestry and a fellow of the Leopold Leadership Program at Stanford University. He is also the director of the Tree Biosafety and Genomics Research Cooperative at OSU that conducts research on mitigation of risks from genetic engineering in forestry.

Sponsors of Science Pub include Terra magazine at OSU, the Downtown Corvallis Association and the Oregon Museum of Science and Industry.

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Steve Strauss, 541-737-7568

Climate center at OSU gets major grant to study forest mortality

CORVALLIS, Ore. – Oregon State University has received a five-year, $4 million grant from the United States Department of Agriculture to investigate increasing impacts of drought, insect attacks and fires on forests in the western U.S., and to project how the influence of climate change may affect forest die-offs in the future.

The researchers will also enhance an earth system model to allow them to predict when forests are becoming vulnerable to physiological stress and then create strategies to minimize impacts of climate, insects and fire.

“The western United States has gone through two decades of devastating forest loss and we don’t even fully know why it happened, much less how to predict these events,” said Philip Mote, director of the Oregon Climate Change Research Institute at OSU and a principal investigator on the grant. “Certainly wildfire, bark beetle infestation and drought play a role, but the intersection of these factors with forest management decisions hasn’t been well-explored.

“A change in severity of drought, for example, can make the difference between trees losing some needles and wiping out the entire stand,” added Mote, a professor in the College of Earth, Ocean, and Atmospheric Sciences at OSU. “The margin between life and death in the forest can be rather small.”

Other lead investigators from OSU on the project include Beverly Law, a professor in the Department of Forest Ecosystems and Society, who will focus on modeling forest processes with the Community Land Model; and Andrew Plantinga, a professor in the Department of Applied Economics, whose expertise is on the economics of land use, climate change and forests.

“Climate variation and extremes can impact trees differently depending on species-specific traits that determine how they compete and respond to environmental conditions,” Law said. “We know little about how physiological limits vary by species, and have not incorporated such knowledge in earth system models.”

The OSU researchers note that forest management decisions could potentially play a role during periods of drought, for example. Drought-stressed trees become vulnerable when they experience vapor pressure deficits – and cannot take in enough water to sustain them, or to remain vigorous enough to help repel invading bark beetles, said Law, who is co-lead principal investigator on the project.

An excess of trees in an area of limited water might benefit from targeted thinning so fewer trees remain to compete for the same amount of water, Law noted. However, forests that already have low densities “are not expected to respond well,” she said.

“What we don’t know,” Mote said, “is what the threshold is between stress and mortality, which trees to thin and how many, and whether such a strategy not only works, but is economically feasible for landowners.”

Law said the intervention strategies “should not result in potentially harmful ecological impacts on habitat and soil quality.”

Among the goals of the project are to:

  • Improve the ability of a leading land surface model to predict tree mortality;
  • Map the vulnerability of western forests to mortality under present and future climate conditions,  particularly in Oregon, Washington, California and Idaho;
  • Apply forest vulnerability data to forest sector models to help land managers better predict ecological and economic outcomes, including timber production, forest recreation and water use.

As part of the study, the researchers will run computer models that will utilize a crowd-sourced computing effort called Weatherathome.net, through which a network of thousands of volunteers will use their home computers to run climate model scenarios. Such a network can equal or exceed the output of a supercomputer.

The OSU grant is part of the inter-agency Decadal and Regional Climate Prediction Using Earth System Models Program, which is coordinated by the National Science Foundation and includes USDA and the Department of Energy.

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Phil Mote, 541-737-5694

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Dying trees

Forest die-off

Of bears and berries: return of wolves aids grizzly bears in Yellowstone

CORVALLIS, Ore. – A new study suggests that the return of wolves to Yellowstone National Park is beginning to bring back a key part of the diet of grizzly bears that has been missing for much of the past century – berries that help bears put on fat before going into hibernation.

It’s one of the first reports to identify the interactions between these large, important predators, based on complex ecological processes. It was published today by scientists from Oregon State University and Washington State University in the Journal of Animal Ecology.

The researchers found that the level of berries consumed by Yellowstone grizzlies is significantly higher now that shrubs are starting to recover following the re-introduction of wolves, which have reduced over-browsing by elk herds. The berry bushes also produce flowers of value to pollinators like butterflies, insects and hummingbirds; food for other small and large mammals; and special benefits to birds.

The report said that berries may be sufficiently important to grizzly bear diet and health that they could be considered in legal disputes – as is white pine nut availability now - about whether or not to change the “threatened” status of grizzly bears under the Endangered Species Act.

“Wild fruit is typically an important part of grizzly bear diet, especially in late summer when they are trying to gain weight as rapidly as possible before winter hibernation,” said William Ripple, a professor in the OSU Department of Forest Ecosystems and Society, and lead author on the article. “Berries are one part of a diverse food source that aids bear survival and reproduction, and at certain times of the year can be more than half their diet in many places in North America.”

When wolves were removed from Yellowstone early in the 1900s, increased browsing by elk herds caused the demise of young aspen and willow trees – a favorite food – along with many berry-producing shrubs and tall, herbaceous plants. The recovery of those trees and other food sources since the re-introduction of wolves in the 1990s has had a profound impact on the Yellowstone ecosystem, researchers say, even though it’s still in the very early stages.

“Studies like this also point to the need for an ecologically effective number of wolves,” said co-author Robert Beschta, an OSU professor emeritus. “As we learn more about the cascading effects they have on ecosystems, the issue may be more than having just enough individual wolves so they can survive as a species. In some situations, we may wish to consider the numbers necessary to help control overbrowsing, allow tree and shrub recovery, and restore ecosystem health.”

As wolves help reduce elk numbers in Yellowstone and allow tree and shrub recovery, researchers said, this improves the diet and health of grizzly bears. In turn, a healthy grizzly bear population provides a second avenue of control on wild ungulates, especially on newborns in the spring time.

Yellowstone has a wide variety of nutritious berries – serviceberry, chokecherry, buffaloberry, twinberry, huckleberry and others – that are highly palatable to bears. These shrubs are also eaten by elk and thus likely declined as elk populations grew over time. With the return of wolves, the new study found the percentage of fruit in grizzly bear scat in recent years almost doubled during August.

Because the abundant elk have been an important food for Yellowstone grizzly bears for the past half-century, the increased supply of berries may help offset the reduced availability of elk in the bears’ diet in recent years. More research is needed regarding the effects of wolves on plants and animals consumed by grizzly bears.

There is precedent for high levels of ungulate herbivory causing problems for grizzly bears, who are omnivores that eat both plants and animals. Before going extinct in the American Southwest by the early 1900s, grizzly bear diets shifted toward livestock depredation, the report noted, because of lack of plant-based food caused by livestock overgrazing. And, in the absence of wolves, black bears went extinct on Anticosti Island in Canada after over-browsing of berry shrubs by introduced while-tailed deer.

Increases in berry production in Yellowstone may also provide a buffer against other ecosystem shifts, the researchers noted – whitebark pine nut production, a favored bear food, may be facing pressure from climate change. Grizzly bear survival declined during years of low nut production.

Livestock grazing in grizzly bear habitat adjacent to the national park, and bison herbivory in the park, likely also contribute to high foraging pressure on shrubs and forbs, the report said. In addition to eliminating wolf-livestock conflicts, retiring livestock allotments in the grizzly bear recovery zone adjacent to Yellowstone could benefit bears through increases in plant foods.

The research was supported by private, state and federal agencies, including the U.S. Geological Survey.

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William Ripple, 541-737-3056

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Grizzly bear
Grizzly bear


Serviceberry

Serviceberries

Climate change threatens forest survival on drier, low-elevation sites

CORVALLIS, Ore. – Predicted increases in temperature and drought in the coming century may make it more difficult for conifers such as ponderosa pine to regenerate after major forest fires on dry, low-elevation sites, in some cases leading to conversion of forests to grass or shrub lands, a report suggests.

Researchers from Oregon State University concluded that moisture stress is a key limitation for conifer regeneration following stand-replacing wildfire, which will likely increase with climate change. This will make post-fire recovery on dry sites slow and uncertain. If forests are desired in these locations, more aggressive attempts at reforestation may be needed, they said.

The study, published in Forest Ecology and Management, was done in a portion of the Metolius River watershed in the eastern Cascade Range of Oregon, which prior to a 2002 fire was mostly ponderosa pine with some Douglas-fir and other tree species. The research area was not salvage-logged or replanted following the severe, stand-replacing fire.

“A decade after this fire, there was almost no tree regeneration at lower, drier sites,” said Erich Dodson, a researcher with the OSU Department of Forest Ecosystems and Society. “There was some regeneration at higher sites with more moisture. But at the low elevations, it will be a long time before a forest comes back, if it ever does.”

Similar situations may be found in many areas of the American West in coming decades, the researchers say, and recruitment of new forests may be delayed or prevented – even in climate conditions that might have been able to maintain an existing forest. While mature trees can use their roots to tap water deeper in the soil, competition with dense understory vegetation can make it difficult for seedlings to survive.

Openings in ponderosa pine forests created by wildfire have persisted for more than a century on harsh, south-facing slopes in Colorado, the researchers noted in their report. And fire severity is already increasing in many forests due to climate change – what is now thought of as a drought in some locations may be considered average by the end of the next century.

If trees do fail to regenerate, it could further reduce ecosystem carbon storage and amplify the greenhouse effect, the study said.

Restoration treatment including thinning and prescribed burning may help reduce fire severity and increase tree survival after wildfire, as well as provide a seed source for future trees, Dodson said. These dry sites with less resilience to stand-replacing fire should be priorities for treatment, if maintaining a forest is a management objective, the study concluded.

Higher-elevation, mixed conifer forests in less moisture-limited sites may be able to recover from stand-replacing wildfire without treatment, the researchers said.

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Erich Dodson, 541-908-0227

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Slow recovery

Slow forest recovery

Land management options outlined to address cheatgrass invasion

The study this story is based on is available online: http://bit.ly/ZO8Ezb

 

CORVALLIS, Ore. – A new study suggests that overgrazing and other factors increase the severity of cheatgrass invasion in sagebrush steppe, one of North America’s most endangered ecosystems.

The research found that overgrazed land loses the mechanisms that can resist invasion. This includes degradation of once-abundant native bunchgrasses and trampling that disturbs biological soil crusts. The work was published today in the Journal of Applied Ecology by researchers from Oregon State University, Augustana College and the U.S. Geological Survey.

“We think there are ways to assess the risks these lands face to reduce the impact of cheatgrass invasion,” said Paul Doescher, professor and head of the OSU Department of Forest Ecosystems and Society, and co-author on the study.

“In the future we should work cooperatively with ranchers and land managers to promote a diverse sagebrush and bunchgrass ecosystem,” Doescher said. “That type of community will protect the native plant and wildlife species and benefit sustainable rangeland use at the same time.”

Researchers suggested that one of the most effective restoration approaches would be to minimize the cumulative impact of grazing, by better managing the timing, frequency of grazing and number of animals.

The researchers also determined that, contrary to some previous suggestions, grazing does not reduce cheatgrass abundance. Cheatgrass was found by this study to be extremely tolerant of even intensive grazing, and the findings “raise serious concern” about proposals to use cattle grazing to help control its spread in areas where native bunchgrasses still persist.

The study outlines the complex ecological processes that can promote cheatgrass invasion and the indirect role overgrazing plays in that process. Increasing gaps and connection of gaps between once-abundant native bunchgrasses allow “a dramatic increase” in cheatgrass invasion, the study concluded. Such gaps could serve as a valuable “early warning indicator” and allow for management approaches that could help conserve and restore the land.

Cheatgrass threatens vast regions of the American West, especially the Great Basin in Nevada and surrounding states. These are areas which were once carpeted by millions of acres of native sagebrush, perennial bunchgrasses and associated wildlife that had evolved with little herbivore pressure. Cheatgrass displaces native grasses and wildlife, can increase fire frequency and ultimately cause an irreversible loss of these native shrub-steppe communities.

This also has grazing implications: cheatgrass is a short-lived annual grass that dries out quickly and provides lower quality forage for much of the year, compared to perennial bunchgrasses.

“Cheatgrass changes the fire regime, and as it spreads, can reach a tipping point,” said Michael Reisner, now an assistant professor at Augustana College who led this study as a doctoral student at OSU.

“After you cross that threshold, a major rangeland fire will come through that takes out the sagebrush, and in most cases the native ecosystem never recovers,” Reisner said. “Many of the plant and animal species that were there can disappear, mostly replaced by cheatgrass that offers poor forage for cattle.”

In a more resistant system, abundant native bunchgrasses can limit the size and connectivity of gaps, which minimizes the water and nutrients available to cheatgrass. Using data from 75 study sites, researchers found that high levels of cattle grazing were associated with reduced bunchgrass cover, with wider and more connections between the gaps that provided an opportunity for cheatgrass to invade.

Cattle trampling also appeared to disturb biological soil crust that offers a second defensive barrier against cheatgrass, and further speeds the invasion. Impacts are greater on the drier and warmer sites within this region.

If the level and amount of gaps indicates that it’s necessary, changes in grazing could help restore bunchgrass cover, maintain a diversity of native grass species and provide much better resistance to cheatgrass invasion, the study concluded. Continued research is needed to quantify the threshold levels of cattle grazing that would still maintain a healthy native ecosystem.

This work was supported by the U.S. Joint Fire Sciences Program, OSU, and the U.S. Geological Survey.

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Paul Doescher, 541-737-6583

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Intact rangeland

Intact rangeland


Grazing impacts

Grazing impacts

College of Forestry

About the OSU College of Forestry: For a century, the College of Forestry has been a world class center of teaching, learning and research. It offers graduate and undergraduate degree programs in sustaining ecosystems, managing forests and manufacturing wood products; conducts basic and applied research on the nature and use of forests; and operates 14,000 acres of college forests.

Starker Lectures to explore forest biomass issues

CORVALLIS, Ore. – The 2013 Starker Lecture Series at Oregon State University will begin Feb. 28 and continue through May with the theme “Forest Biomass: Energy and Beyond.”

Leading experts will examine the changing use of forest biomass to produce energy, fuels and chemicals, while considering technical, economic, environmental implications, wildlife, soils and other issues. The lecture series will conclude with a field trip in Benton and Lane County.

All of the events are free and open to the public, and all lectures will be on a Thursday afternoon from 3:30-5 p.m. in Richardson Hall Room 107.

A capstone field trip titled “A Tour of Forest Biomass – from the Ground Up!” will be held May 30 from 9 a.m. to 4 p.m. It will feature visits to forest biomass production sites and energy facilities, and a discussion of on-the-ground and facility supply and processing considerations, including technical, environmental and economic. Advance registration for the field trip, and more information about all of the lectures, is available online at http://starkerlectures.forestry.oregonstate.edu/

The speakers and their topics include:

  • Feb. 28: “Sustainable Integrated Forest Biorefineries,” with Shri Ramaswamy, professor at the University of Minnesota.
  • April 11: “Wood to Wing: Envisioning an Aviation Biofuels Industry Based on Forest Residuals in the Pacific Northwest,” with Michael Wolcott, director of the Institute for Sustainable Design at Washington State University.
  • May 2: “Environmental Considerations,” a panel discussion including Matthew Betts, associate professor at OSU, discussing forest wildlife habitat; Robert Harrison, a professor at the University of Washington discussing forest soil productivity; and Elaine Oneil, research scientist with the University of Washington discussing forest product life cycle analysis.
  • May 16: “Oregon’s Biomass Experience: An Integrated Approach to Forest Biomass,” with Matt Krumenauer, senior policy analyst with the Oregon Department of Energy.
  • May 30: “A Tour of Forest Biomass – from the Ground Up!” capstone field trip.

The Starker Lecture Series is sponsored by the Starker family in honor of T.J. and Bruce Starker, and is supported by the Oregon Forest Resources Institute and the OSU College of Forestry.

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Julie Howard, 541-737-1591

“Food for Thought” lectures on ag, food biotechnology begin in January

CORVALLIS, Ore. – The “Food for Thought” community lecture series will begin its eighth season this month at Oregon State University, bringing internationally recognized experts to discuss new options for food and fuel production, and implications for the environment, public health, and their economic and social viability.

The series emphasizes the roles of biotechnologies, in both novel and traditional forms.

All lectures will be at LaSells Stewart Center on the OSU campus on Wednesday or Thursday evenings, beginning at 7 p.m. The talks, which are followed by audience discussion and a chance to meet with speakers, are free and open to the public.

The series is part of OSU’s Outreach in Biotechnology program based in the College of Agricultural Sciences, and is designed to promote understanding of biotechnologies and related issues. The series and outreach program are supported by the OSU College of Agricultural Sciences and the OSU College of Forestry.

The first presentation will be Thursday, Jan. 24, by Prabhu Pingali, deputy director of agricultural development at the Bill and Melinda Gates Foundation. His lecture is titled “Green Revolution 2.0: making it work for hunger and poverty reduction in the developing world.” He will provide a retrospective on the first Green Revolution, including both its achievements and limitations in increasing global food supply and reducing poverty, and the urgent need for a second revolution to sustainably feed the world and enhance the prosperity of small farmers.

There are two other lectures in the series on Wednesday evenings:

  • Feb. 13: “Global economic and environmental impacts of agricultural biotechnology.” Nicholas Kalaitzandonakes, an endowed professor of agribusiness and the director of the Center for Economics and Management of Agrobiotechnology at the University of Missouri, will discuss the distribution of economic benefits and costs from the first wave of transgenic biotechnologies in agriculture, including for farmers, companies and consumers.
  • March 13: “Technology and food marketing in the age of animal welfare.” Joy Mench, a professor in the Department of Animal Science and the director of the Center for Animal Welfare at the University of California, Davis, will discuss what animal welfare means from both scientific and ethical perspectives, and how it is represented in the marketplace to enable consumers to make more informed purchasing and care decisions.

More information about the speakers and their presentations will be available online at http://oregonstate.edu/orb. Podcasts of 38 previous lectures are available online (downloadable from iTunes U and YouTube), as well as study guides prepared for teachers of undergraduate students and honors students, grades 10-12.

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Steve Strauss, 541-737-6578

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Prabhu Pingali

Prabhu Pingali