OREGON STATE UNIVERSITY

environment and natural resources

Study: Vast sagebrush ecosystems a victim of climate change?

CORVALLIS, Ore. - The sagebrush lands of the Great Basin, one of the largest ecosystems in the United States, may be reduced to a fraction of their current area due to ecological changes already under way and climate shifts that will hasten their demise, a new study suggests.

This vast, semi-arid region, dominated by frost-tolerant sagebrush and native grasses, is already suffering impacts from invasive species, fire suppression and the encroachment of other woody vegetation. The future will also bring increases in temperature that may allow frost-sensitive species from the Southwest to move hundreds of miles north and further displace the sagebrush, scientists say.

These findings were presented recently at a professional meeting and are being published in the Transactions of the North American Wildlife and Natural Resources Conference by researchers from Oregon State University and the U.S.D.A. Forest Service.

The hottest climate scenario would reduce sagebrush to about 20 percent of its current area in the Great Basin, a fairly rapid change in hundreds of thousands of square miles of the American West. Increases in woody vegetation and fire are predicted. Only a few small areas of sagebrush in southern Wyoming, the northern edge of the Snake River plateau, and small areas of Washington, Oregon and Nevada are expected to survive and persist under all scenarios, researchers say.

"Increases in temperature due to global warming will be the driving force in these changes, along with less-predictable changes in the summer rainfall regime," said Ronald Neilson, a professor of botany at OSU and ecologist with the Forest Service. "A major change will be that as the climate warms, woody vegetation now confined by cold temperatures to the Southwest may move into the higher plateaus of the Great Basin.

"Given the flat nature of much of this terrain, once the woody vegetation gets up and over the 2,000-foot elevation, it will be like opening the floodgates," Neilson said.

Changes in precipitation are most difficult to predict in future climate scenarios, said Neilson and Dominique Bachelet, an OSU associate professor of bioengineering. Earlier work by these researchers suggested both a decrease in frosts and increases in precipitation over much of the interior West, triggering a dramatic increase in wood expansion at the expense of sagebrush shrub land, and a corresponding increase in fire due to the increased fuel load.

More problems with fire in the wild land-urban interface are also probable, the researchers said. The amount of fire suppression conducted by land managers is an unknown variable that will affect total vegetation growth, and could result in a dramatic increase of the overall biomass of these regions in future years, Bachelet said.

"What's most certain is the rising temperature, which is going to allow a lot more oak, mesquite and invading grasses into new areas," Neilson said. "Precipitation is harder to predict and may be quite variable, due to inter-decadal climate patterns that appear to be getting even more volatile and intense. We could see some decade-long periods of drought during what should be a period of overall higher precipitation."

There may actually be more plant and animal diversity under the new scenario than the sagebrush ecosystems of the past, the study indicated. And the increased amounts of vegetation in the Great Basin, inadvertently, might support a U.S. policy of increased carbon sequestration in ecosystems. But as huge areas of the American West face these changes in their ecology, some existing sagebrush ecosystem species may also go extinct.

Seven different climate scenarios were considered in this study, and it's uncertain exactly which one will prevail. As models continue to get more refined they seem to be trending toward the hotter climate scenarios, Neilson said. And the rate of ecological change may be so rapid that the early winners will be invasive weeds that can travel easily and adapt to a wider range of conditions, he said.

The existing sagebrush biome of the western U.S. is one of the two or three largest ecosystems in the nation, comparable to the Great Plains and the eastern deciduous forest. The system tends to be very hot in the summer and subject to recurring hard frosts in the winter - a climate to which hardy sagebrush with its deep roots is particularly suited. Sagebrush and the species associated with it - such as sage grouse, sage thrashers and pygmy rabbits - dominate large areas of Nevada, Oregon, Washington, Idaho, Utah, Wyoming, Montana and other western states.

These ecosystems have already undergone intense changes since European settlement, with some estimates that intensive agriculture, grazing pressure and other impacts have reduced the sagebrush lands to less than half of their original size.

"Aside from the findings of this study in particular, one thing I find most striking is the overarching impact of humans," Bachelet said. "We've brought fire suppression, air and water pollution, we've introduced competitive exotic species, and we are responsible for the incessant expansion of agricultural and urban areas. This has created huge changes for natural systems to adapt to, and may be the ultimate cause of mass extinctions."

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Ronald Neilson, 541-750-7303

Invasion of New Beach Grass Could Weaken Shoreline Protection

CORVALLIS, Ore. - An invasion of American beach grass is under way along the Oregon coast, threatening to change dune ecology and reduce the ability of dunes to protect roads, property and towns from coastal storms.

Scientists at Oregon State University have documented a slow but steady takeover by this beach grass, an invasive species. They found that protective “foredunes” covered by the new grass species are only about half as high as those created by the European species of grass that were formerly dominant.

This phenomenon has already occurred from Long Beach, Wash., to Pacific City, Ore., and is continuing to spread, the researchers say.

“This decrease in dune height may translate into a significant decrease in coastal protection from storms and tsunamis,” said Eric Seabloom, an OSU assistant professor of zoology.

In continuing studies, scientists plan to use oceanographic models to show just how much protection is lost when European beach grass is replaced by American beach grass.

The European grass – also an invasive species – has been dominant since it was first introduced to the area around the turn of the 20th century, to help stabilize blowing sand on the coast.

“It did its job extremely well,” said Sally Hacker, an OSU associate professor of zoology and expert on marine and estuarine communities. “Without it, the sand would cover towns and roads.”

The European beach grass did so well that by the 1930s it had spread along the entire Oregon coast, and created an extensive “foredune” system, large protective sand hills found in front of almost every sandy beach in Oregon. These dunes can provide significant protection for homes, roads, towns and other infrastructure, and serve as a barrier against flooding during major storm surges and perhaps even tsunamis.

But the second invasion by the American beach grass species had gone practically undetected. Introduced near the mouth of the Columbia River in the mid-1930s, also to stabilize beaches, American beach grass tends to out-compete its European cousin. The status of this beach grass variety went unnoticed for more than 50 years, until Seabloom and a colleague discovered it had crept as far south as Tillamook Head and as far north as the Olympic Peninsula.

Surveys of the entire Oregon coast have determined that the current range of domination of American beach grass extends from Long Beach, Wash., to Pacific City, Ore. But even beyond that, from Pacific City south, most of the beach grass is the American beach grass, with just a few pockets of European beach grass.

“Lower dune heights, increasing wave heights that have been observed over the last 50 years, and global climate change could create a scenario in which the dunes no longer serve a coastal protection function,” Hacker said.

Beyond the protection concerns, there are other ecological issues in play as well.

While the foredune system created by European beach grass is good for coastal landowners, it is not so good for endangered beach plant species and the federally-threatened Western snowy plover, scientists say. As more sand accumulates in growing stands of beach grass, the land behind the dune tends to get “terrestrialized,” or turned into wetlands and forest habitats.

“The willows and other trees and larger shrubs you often see behind the dunes are an indication that wetlands are being formed in the mini-valley behind the dunes,” Hacker said.

As that process advances, beach habitat disappears, taking with it the plovers’ critical nesting grounds. The southward march of the American beach grass species could reverse the terrestrialization trend, as the American variety creates a much smaller foredune.

Hacker and Seabloom have received funding from Oregon Sea Grant to study the impacts and interactions of these invasive grasses on the Oregon coast. They are also working with Peter Ruggiero, a geomorphologist in the Department of Geosciences at OSU, to understand the coastal protection capabilities of dunes along the coast.

Source: 

Sally Hacker,
541-737-3707

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foredune
A housing development behind a foredune created by European beach grass at Pacific City, Ore.

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A foredune created by European beach grass at Cape Kiwanda, Ore. The bright green grass in the middle of the photo is American beach grass invading the foredune.

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European beach grass on the beach at Cape Kiwanda, Ore.

Conservation Biology Program at OSU Ranked First in Nation

CORVALLIS, Ore. – Conservation biology research at Oregon State University has been ranked in a new survey as the best of 315 such programs in the United States and Canada.

The rankings, done for the first time by the journal Conservation Biology, the leading professional journal in this field, point out that OSU had the second highest number of publications, the greatest number of “citations” that reflect the scientific significance of a publication, and the number one overall ranking.

California universities – at Santa Barbara, Davis, Santa Cruz, and Berkeley – held four of the next five highest rankings, along with the University of Wisconsin at Madison. The University of Washington was ranked seventh and Stanford University tenth. In this evolving field, the research programs of these leading West Coast universities were far ahead of many prestigious schools in the Ivy League, Big Ten and other major eastern colleges.

Conservation biology is one of the younger scientific disciplines, but of growing importance. It brings together scientists from such traditional fields as botany, ecology, atmospheric science, oceanography, forestry, fisheries, agriculture and zoology – as well as social and economic perspectives - to study and learn how to protect the Earth’s biological diversity. Research can range from endangered species and ecosystem function to the effects of global warming, often exploring the environmental and ecological impact of humans.

“We’re particularly proud of this ranking, as it speaks not only to our faculty strengths, but to so much that we value at OSU,” said OSU President Ed Ray. “As the planet’s climate changes and the world looks for answers, OSU’s work in this field will be of ever increasing importance, and our faculty will be collaborating with colleagues in similarly outstanding programs to push the frontier of conservation biology forward.”

OSU in recent years has also received extremely high rankings in related fields, such as first in agricultural sciences, geosciences and forest ecology. A survey last year of forest faculty, in fact, showed that peers rate the OSU College of Forestry the best in North America.

Conservation biologists are integrating the findings of physical sciences, such as marine or atmospheric science, with the biological sciences, in ways that will help humans understand or predict the dangers facing various species and ecosystems, and ways those concerns might be addressed. They provide information about the many valuable services provided by biodiversity and healthy ecosystems, the threats posed by overpopulation, the effects of habitat loss.

Oregon provides a unique setting for conservation biology research, experts say, with an enormous diversity of land forms and biodiversity. Within a few miles, the region changes from ocean ecosystems to one of the world’s largest temperate rain forests, agricultural valleys, populated urban areas, alpine peaks and high desert. Studies in recent decades have ranged from near-shore ocean ecosystems to forest ecology, endangered species, terrestrial pollution, salmon health, stream ecology, the impacts of climate change and amphibian declines.

In recent years, OSU scientists from oceanography and zoology discovered and warned about the “hypoxic zones” of increasing concern off the Oregon coast, in which changing ocean conditions are causing large-scale die-offs of crabs and other marine species. Several papers from the College of Forestry have questioned conventional approaches to salvage logging and replanting after forest fires.

One recent study co-authored by an OSU researcher indicated that much conservation biology research around the world is dictated by personal interests and convenience, rather than the greatest threats to biological diversity. Other work that has gained international attention outlined the role of wolves, cougars and other top predators in protecting plant and animal diversity in national parks and elsewhere.

Conservation biology research at OSU has earned millions of dollars of research support from leading federal agencies, private foundations and local governments, and the university recently formed an Institute for Natural Resources to better link scientific research with the biological, social and policy issues it could help address. OSU also benefits from its close collaboration with other federal research agencies that are on or near the university’s campus.

“Many of the highly ranked schools, such as Oregon State University and Colorado State University, have a rich history of applied ecological research stemming from their designation as federal land grant universities,” the journal noted in its report. “These schools in particular have close ties to federal and state natural resource–based agencies, as evidenced by their interactions with researchers at several U.S. Geological Survey, U.S. Department of Agriculture Forest Service, and U.S. Environmental Protection Agency laboratories.”

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Ed Ray,
541-737-4133

Forecast: After Slow Start, Western Oregon May be Cooler, Wetter – and Snowier?

CORVALLIS, Ore. – In his years of producing a fall and winter weather forecast for the state, George Taylor has rarely if ever predicted snow for western Oregon – and true to form, he won’t go too far out on a limb this year.

But Taylor, who manages the Oregon Climate Service at Oregon State University, concedes that it is a good likelihood this year.

“The stars are lined up that way,” he said with a laugh.

Taylor and colleague Cadee Hale have just issued the Oregon Climate Service’s forecast for October through March and the bottom line is that once we get through October, temperatures are expected to be slightly cooler than average in western Oregon, with average to above-average precipitation. And, they say, there is “a good chance” for low-elevation snow in western Oregon.

Oregon residents east of the Cascades, on the other hand, will see warmer-than-average temperatures and average precipitation through the fall and winter.

The brightest forecast may be for skiers and ski resort owners: Snowpack in the Cascade Mountains is expected to be well above-average this year.

“We anticipate a very good ski season,” Taylor said.

One of the reasons for predictions of cooler temperatures and a higher possibility of snow in western Oregon is the development of La Niña-like conditions near the equatorial Pacific. While it is too early to conclude that a La Niña event will take place this winter, cooler temperatures in the tropical Pacific and stronger trade winds suggest it is a possibility.

La Niña events usually result in cooler, wetter winters for the western portions of the Pacific Northwest.

Every year Taylor makes a prediction for fall and winter weather based on a number of factors, culminating in selecting "analog years" that most closely resemble current conditions. He takes into account long-term wet and dry cycles (known as the multi-decadal phase), El Niño and La Niña episodes, sea level pressures, temperatures, wind speeds, solar cycles and even hurricanes, which have a surprisingly strong correlation to Northwest climate.

"Based on a composite of analyses, we are usually able to identify four or five analog years that had similar conditions during the first several months of the year, which helps us predict what the weather may be like in the fall and winter," Taylor said.

Taylor and Hale were able to find four analog years with conditions comparable to this winter. Each had some extreme weather events during those years.

• 1952-53 – A major flood hit western Oregon in January, and a major windstorm that same month caused significant damage;

• 1953-54 – A heavy rainstorm fell in western Oregon in November; two strong windstorms followed in December, and three major storms – with wind, rain and snow – struck in January.

• 1970-71 – A major windstorm in March affected the entire state. December was wet with snow in the low elevations. A heavy snowstorm struck the entire state in January, dumping 11 inches of snow in Salem and nine inches in Portland.

• 1988-89 – There was heavy rain with localized flooding in November, followed by an extremely dry month in December. Record low temperatures and heavy snow arrived in February, resulting in five deaths. Central Oregon was hit by flooding in March, the same month a major windstorm killed three people.

It is difficult to predict extreme weather events based on analog years, Taylor pointed out, and there is a possibility of heavy rains, windstorms and even heavy snow. Three of the four analog years included snowstorms and two of those years had heavy snow, even in western Oregon.

“I will say that there is a good chance of at least one low-elevation snow event,” Taylor said. “And the mountains should see a lot of snow after a slow start. We expect mountain snows to accumulate quickly in November and become significant in January and February.”

The entire forecast and background on how Taylor and Hale arrive at their conclusions is available at the Oregon Climate Service website at: http://www.ocs.oregonstate.edu/index.html

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George Taylor,
541-737-5694

New Tools Available to Tackle Epidemic of Swiss Needle Cast

CORVALLIS, Ore. – Forestry researchers at Oregon State University have developed a computerized risk analysis system to help predict the vulnerability of specific sites to Swiss Needle Cast, a serious problem in Coast Range forests that can cut tree growth and causes losses of more than $200 million a year.

The model, which is now in prototype form and should be fully available to landowners by early next year, may be an important tool to help address a resurgence of the Swiss Needle Cast epidemic that has occurred just in the past couple years, almost doubling from its level in 2004.

Other initiatives are also under way in the Swiss Needle Cast Cooperative based at OSU, which was founded 10 years ago as a cooperative effort of private industry, academia and other government agencies.

“This new risk-rating model should be a reliable predictive tool so that landowners can make more informed decisions on what tree species to plant,” said David Shaw, an assistant professor in the Department of Forest Science at OSU, and director of the cooperative. “Some of our co-op members are pretty excited about its potential to help address this problem.”

Swiss Needle Cast, a fungal disease of Douglas fir that is native to the Pacific Northwest, is mostly a problem in areas within 20 miles of the ocean, where warm, wet conditions favor its growth. It’s a cyclical problem that is made more severe by warmer winters, wetter springs and extended drizzle.

Historically, the fungus was a minor concern in this region, which was dominated by hemlock and Sitka spruce trees, with only smaller amounts of Douglas fir. But with intensive forest management during the past century, the varied tree species were often harvested and replaced with a monoculture of Douglas fir, which grew well and commanded higher market prices.

“Other than with the concerns about Swiss Needle Cast, Douglas fir grows exceptionally well in the Coast Range, and in past decades a couple million acres were converted to it,” Shaw said. “But now we have a perfect storm of conditions favoring this fungus, with dense plantations of the trees it infects and favorable climate conditions.”

At its worst, Swiss Needle Cast can cut Douglas fir growth by up to 50 percent, causing new-growth tree needles to turn yellow and be “cast off.” As recently as 2004, efforts to change the mix of tree plantations had shown some success and cut the acreage of significant infection in half, to less than 200,000 acres. But a new survey shows the disease has made a dramatic recovery and once again is nearing peak levels, affecting 338,000 acres. A particular hot spot is the low elevation areas and hills around Tillamook, where conditions appear optimal for the disease.

“Most of what we’re seeing is probably variation driven by weather,” Shaw said. “This is not a problem we’re going to eradicate any time soon, so we have to develop ways to deal with it.”

The new model is being developed at OSU with funding from the Swiss Needle Cast Cooperative, by Jeff Stone, an associate professor of botany and plant pathology, and Len Coop of the Integrated Plant Protection Center. It can tell landowners whether a very specific plot of land will be at low, moderate or high risk to develop significant Swiss Needle Cast infection. This can help guide decisions on what to plant for future tree rotations. The model incorporates a diverse range of data about topography, climate, local weather patterns, historic disease problems and other relevant issues.

For those with existing problems, there are fewer options. Use of fungicides is effective but too expensive to use on a broad scale. OSU studies in the Swiss Needle Cast Cooperative have determined that thinning of the weakest Douglas-fir and replacement with hemlock or spruce can be of some value. It helps to avoid nitrogen fertilization, which favors the growth of fungus. And in extreme cases, some landowners may even consider conversion of their existing forest to different species.

Within five to 15 years, Shaw said, other research may produce Douglas fir varieties with improved Swiss Needle Cast tolerance, through studies that are now under way.

A series of workshops will be conducted next year to help private and industrial landowners learn more about the new risk-rating model and other steps to address this problem, Shaw said.

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David Shaw,
541-737-2845

OSU RECOGNIZED FOR CONTRIBUTIONS TO NEW NUCLEAR DESIGN

CORVALLIS - Work done in an upgraded and improved test facility in the Department of Nuclear Engineering and Radiation Health Physics at Oregon State University has helped create the "next generation" of nuclear power reactors that many experts believe will herald the future of nuclear energy.

This fall, tests done in this facility, along with much other work in a massive, international project, led to the final approval by the Nuclear Regulatory Commission of the AP 1000 Generation III-plus, an advanced nuclear reactor design from Westinghouse that will soon be available for international and domestic orders.

For its work in this field, the Advanced Thermal Hydraulic Research Laboratory at OSU, in collaboration with TIC The Industrial Company, received two awards from the Associated Builders and Contractors. The awards recognize their achievements in upgrading the testing facility from the AP600 design to the AP1000 design.

These reactor designs are much simpler, less costly to build, and based on "passively safe" concepts that take advantage of natural forces such as gravity, natural circulation, convection and evaporation for improved safety. They have fewer pumps, piping, valves, and cables, and overall less items to install, inspect or possibly fail than a traditional plant.

At OSU, these processes and design elements were built in one-quarter scale in the test laboratory, and tested repeatedly under varying conditions. The recent major upgrade to the facility involved construction and design of new electrical, mechanical, and pipe components, new data acquisition hardware, tracking instrumentation, and state of the art computer hardware and software.

"OSU is very proud of the important research we contributed to assist Westinghouse and the Nuclear Regulatory Commission in their determination that this reactor design concept meets the design requirements of reducing costs and enhancing safety," said Andrew Klein, professor and head of the Department of Nuclear Engineering and Radiation Health Physics.

This project is one of OSU's largest collaborative research efforts with private industry. Many nuclear industry officials say that power reactors of the type created by this research should be the safest, most economical nuclear power plants ever designed, and could lead to a re-birth of the nuclear power industry both in the U.S. and around the world.

Leaders of the OSU Thermal Hydraulics and Reactor Safety team include Jose Reyes, Qiao Wu, Brian Woods, John Groome and Teresa Culver, as well as both graduate and undergraduate students.

Source: 

Teresa Culver, 541-737-2644

Extreme Weather Stresses Douglas-Firs

CORVALLIS, Ore. – Driving through forested regions surrounding Oregon's Willamette and Umpqua Valleys this summer, you may have noticed reddish dead branches, tops or whole dead Douglas-fir trees.

These trees may be reflecting physiological stress from the effects of extreme swings in weather over the past year and a half, says Rick Fletcher, forester with the Oregon State University Extension Service.

After experiencing months of saturated soils in the winter, then bone dry periods in the spring and summer, some Douglas-firs planted in less than ideal situations are showing what some foresters call "flare out," the occasional dead branch, top or the entire tree.

So far, most of the stressed trees seem to be limited to Douglas, Lane, Benton, Linn, Yamhill, Polk and Marion counties, from the areas surrounding McMinnville, south to Roseburg, according to local OSU Extension foresters. Douglas-fir in western Oregon's northern and westernmost counties, including Clackamas, Washington and the coast seem relatively unaffected. So far, economic impacts of this stress on forestry are unknown.

"Starting in December, 2005 and January, 2006, we experienced 44 days of straight precipitation, an all time record of consecutive days," said Fletcher. "These conditions left many Valley foothill sites with water logged soils for weeks on end, a recipe for disaster for wet-intolerant species like Douglas-fir."

In waterlogged soils, many fine roots die, leaving the tree to try and regrow these roots in the spring, stressing the trees, Fletcher explained.

"The summer of 2006 was very hot, with three separate periods of temperatures in excess of 100 degrees," said Fletcher. "These hot, dry conditions were with us for 110 straight days, putting trees in severe moisture stress.

"This one, two, three punch was devastating for trees on marginal soil types, leaving them easy picking for a host of insects and diseases," Fletcher said. "Samples I have examined are suffering from a range of problems such as twig weevils, coneworms, root rot and bark beetles. It would be too easy to point fingers at one of these problems as being the cause, when in reality, it is the weather conditions that are much more to blame."

Typically, species like Douglas-fir find these extremes in soil conditions marginally acceptable for growth, under more average climate conditions, said Fletcher. But this series of events during the past 17 months have just been too harsh for Douglas-fir on these sites.

While many different tree species seem to be affected, young Douglas-fir on marginal growing sites are taking the worst of the damage, he said. "Around the Willamette Valley foothills, Douglas-fir has been planted and comes in naturally on soils that are shallow and droughty, seasonally wet, or in some cases both."

Flare-out is common to the south as well, in the Umpqua Valley, according to John Punches, OSU Extension forester in Douglas County. "The situation is most common here on lower elevation, south and west facing slopes that tend to be hotter and drier, where moisture stress is exacerbated by unmanaged competition from grass and brush," he said. "Local landowners often assume that Doug-fir will grow on these sites. They may under optimum weather conditions, but these less than ideal conditions invariably result in significant branch, top and whole tree mortality."

Some commercial Christmas trees are being affected as well, said Dave Shaw, Extension forest health specialist at OSU. But Shaw thinks the stress seems to be limited to those trees growing in soils that are less productive—those waterlogged in the winter and dry as a bone in the summer.

"Across any given property it is likely that the problem is patchy and not evenly distributed," said Shaw. Once the rains come in, the extent of impacts will be clearer, he said. Then, healthy trees will green up and stressed parts will not.

These OSU Extension foresters say that the growing conditions for Doug-fir are looking more moderate this year.

"Even though our spring was short on precipitation, overall, the growing conditions we have been experiencing in 2007 are much more average than what we experienced in 2006," said Fletcher. "But it will take time for the trees to recover from 2006."

Similar Douglas-fir die-off occurred in other recent years, especially in 1998-99, said Fletcher.

For more information and photos of these problems, visit the Oregon Department of Forestry publication entitled: "Dead Branches, Dead Tops, and Dead Douglas-fir Trees - The Interaction of Water Stress, Insects and Disease," at http://egov.oregon.gov/ODF/PRIVATE_FORESTS/docs/fh/deadbr99.pdf

Source: 

Rick Fletcher,
541-766-3554
(Linn, Benton)

200-year experiment changes face of forest management

CORVALLIS - A 200-year study of rotting logs in the Oregon Cascade Range is only 10 percent complete, but findings from this research have already helped save hundreds of millions of dollars, improved forest health and shattered conventional wisdom about the decay of woody debris.

It also has attracted the interest of forest managers from around the world.

This work was begun 20 years ago by scientists from the College of Forestry at Oregon State University with 530 logs at the H.J. Andrews Experimental Forest near Blue River, Ore. The research was seen as a way to more rigorously document the process of wood decay and the value it provides in nutrient release, soil enhancement and other issues.

Even though the study is far from complete, it has already achieved many of these goals and raised other important questions that will continue to affect modern silviculture and the understanding of forest ecology, said Mark E. Harmon, the Richardson Chair and Professor of Forest Science at OSU. The work has been funded by the National Science Foundation and the U.S.D.A. Forest Service.

"Much of what we've found has run contrary to the conventional wisdom and is not what we expected," Harmon said. "And this long-term, intensive study of the decay of forest debris and logs has raised considerable awareness of this issue among forest managers."

Two decades ago, forest harvest operations usually "cleaned up" a site after logging, removing most of the debris at considerable cost and effort. As this and other studies showed the compelling ecological value of that material, the debris is now largely left where it is, making the forest healthier in the long run and saving hundreds of millions of dollars in unnecessary work.

"When this study began, we still assumed that most debris and logs decayed in more or less the same way, only releasing their stored-up nutrients after decades or centuries of decay," Harmon said. "It's now understood that there are large differences between the decay rate caused by different decomposers of different tree species, and that some nutrients from dead wood begin to enrich the forest almost immediately.

"That's a huge change in our thinking, and there are still a lot more changes to come," he said.

Among the other findings of the first 20 years of this work:

  • As much as one-third of the nitrogen in Pacific Northwest forests, one of the key nutrients that limit vegetation growth, appears to come from nitrogen fixation processes within rotting logs, in addition to that being slowly released from the wood itself.
  • Nutrient release begins far more quickly than ever anticipated, from both decaying fungi and the leaching effects of persistent rains.
  • The "brown rot" fungi that cannot break down lignin in trees leaves structural material behind to help form the next generations of forest floor and ultimately soil. White rot fungi, by contrast, degrade all parts of the wood, leaving almost nothing behind and decaying far more rapidly but only on some tree species.
  • Although some wood (such as Douglas-fir) resists decay, mechanisms such as mushroom growth on downed logs work to drain nitrogen from these logs, much more than had been understood.
  • There is a 10-fold difference in wood decay rates among dead trees. True firs such as silver fir will decay far more rapidly than other species, as much as 5-6 percent a year and may be gone in 60 years or less. Other species such as western red cedar or Douglas-fir may persist for hundreds of years.
  • Some parts of a log will decay and release nutrients much more quickly than other parts, leading to complex patterns that cannot be predicted by considering just the "average" condition of the wood.
  • Decay processes are dynamic and constantly changing, and they affect everything from nutrient release to soil changes, stream sedimentation, and plant, animal and fish habitat.

    "In the past we just didn't pay much attention to what was decaying, and how, and what the ecological implications of that were," Harmon said. "We now know there are huge differences between tree species, that some fungi decay some species and not others, and that all of these factors will play a role in sustainable forestry and overall forest health."

    In the future, Harmon said, trees increasingly will be planted that are never meant to be harvested - by design, they will be left to decay and play certain roles in forest ecology, for the health of plants, trees, microbes and wildlife. With large trees that have commercial value, it's still not certain exactly how many must be left for the complete range of forest benefits, he said, and findings on that issue will continue to emerge from studies such as this.

    Oddly enough, some of today's evolving forest management systems may seem more similar to those in the early days of the Pacific Northwest forest products industry - when large amounts of less-valuable wood was left behind in practices that were later deemed "wasteful" and changed dramatically after the 1940s, in order to harvest more of the wood and leave a clean site behind.

    The findings of these studies and their temporal scope have been so compelling, Harmon said, that they have attracted not only forest scientists but artists.

    "We originally began this work assuming it would be of interest only to forest researchers and ecologists," Harmon said. "Now people from all over the world are watching these studies, and many experts think of nutrient release as one of the last frontiers in understanding the role of dead trees in forest ecology.

    "Writers have done features on the work in national publications. Even artists and sculptors have worked with us to portray the fascinating, natural processes of forest growth and long-term changes."

  • Media Contact: 
    Source: 

    Mark E. Harmon, 541-737-8455

    DVD project helps land managers plan for the future

    CORVALLIS - Rural land managers reflect on their past and plan for the future in a new DVD produced by the Oregon State University Extension Service.

    "Landmarks in Conservation" is designed to help rural landowners, farmers, ranchers and foresters devise sustainable natural-resource management plans for their operations. The interactive multimedia project utilizes both DVD and web technologies.

    "This project draws on the experiences of nearly 30 land managers from across our state," said Bill Braunworth, agriculture program leader for the OSU Extension Service. "It demonstrates the importance of resource management planning, whether you operate a five-acre farm near Portland or a 100,000-acre ranch in southeast Oregon."

    The DVD and its companion website are a cooperative effort funded by the OSU Extension Service, the USDA Natural Resources Conservation Service and a private gift to the OSU Foundation. The DVD holds nearly two hours of video clips, while the website serves as a gateway to more than 120 print, video and online resources.

    "We are excited about the scope and potential impacts of this project," said Sara Magenheimer, public affairs specialist with the Natural Resources Conservation Service. "It presents technical, research-based information in an understandable, user-friendly fashion."

    The project's non-linear structure helps educators customize classroom, workshop or field instruction to meet the needs of specific audiences. It also empowers individuals to select the learning pace, media formats and content that work best for their own situation.

    "The insights and stories of these Oregon land managers are really what bring this project to life," Braunworth said. "They help viewers understand that connection between healthy natural resources and a profitable, sustainable operation."

    "Landmarks in Conservation" (DVD-1) is available from OSU Extension and Experiment Station Communications for $19.95 per copy plus $4 shipping and handling. Discounts are available when purchasing 10 or more copies. To order the DVD, visit http://extension.oregonstate.edu, call toll-free, 1-800-561-6719, or fax your request to 541-737-0817.

    Source: 

    Bill Braunworth, 541-737-1317

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    Scientists develop groundbreaking new model for impacts of dams

    CORVALLIS, Ore. – Scientists have developed a new system to help policy makers better assess the costs and benefits of building dams – the first system of its kind to use an interdisciplinary approach to simultaneously evaluate the distribution of biophysical, socio-economic and geopolitical impacts of dams, according to one of the study’s co-authors.

    “We as scientists tend to look at things through our own tiny little drinking straw, studying our one narrow field,” said Bryan Tilt, an assistant professor of anthropology at Oregon State University and one of the study’s authors. “When it comes to dams, we felt a broader perspective was needed. Because when you put up a dam, it affects whole ecosystems and whole communities.”

    The study, which was funded by the National Science Foundation, is part of a special issue on dams featured in the summer edition of the Journal of Environmental Management. The entire special issue was edited by Tilt and Desiree Tullos, an assistant professor in the Department of Biological & Ecological Engineering at OSU. Tullos is another co-author on the study and the principal investigator on the National Science Foundation grant.

    Each scientist was brought in for their piece of the dam puzzle. Lead author Philip H. Brown of Colby College is an economist who studies microeconomic issues in economic development. Tullos is an environmental engineer with expertise in ecohydraulics and hydraulic modeling. Tilt is an environmental anthropologist who studies the social and environmental impacts of rural development, with a special focus on China, where dam construction far outpaces any other nation. Darrin Magee of Hobart and William Smith Colleges is a geographer specializing in energy and water issues in China. And OSU’s Aaron Wolf studies water resources policy and conflict resolution.

    The scientists have developed what they call an Integrative Dam Assessment Modeling tool, or IDAM. The model was designed as a decision-support tool that policy makers can use to understand holistically the impacts, costs and benefits of building a dam in any area.

    “It can be used anywhere, with some modifications,” Tilt said, adding that the researchers have used the tool to study the impact of dams in China and are continuing that research through a new National Science Foundation grant this summer.

    The dam assessment tool measures the costs associated with a proposed dam development project and also measures the possible benefits. Each of the diagrams in the tool consists of 27 individual indicators of the effects of dam construction, divided into socio-economic, geopolitical and biophysical themes.

    In the published study, the authors illustrated the use of the IDAM tool by testing it on two hypothetical dams with different design characteristics.

    This summer the research team travels to China again where it will put the IDAM tool into practice on real dams. Tilt said they will collect data on two rivers: one that has several dams on it already (the Upper Mekong River) and one that is slated for dam development in the near future (the Nu River, also called the Salween).

     

    Media Contact: 
    Source: 

    Bryan Tilt, 541-737-3896