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Forests, Climate Change, and the Future
Forests, Climate Change, and the Future

 

Forests support vast networks of biodiversity, provide abundant raw materials, and remove the greenhouse gas carbon dioxide from the atmosphere. The environmental and economic value of the nation’s forested landscapes is perhaps too great to calculate, which is why public and private organizations make enormous investments to protect and manage these vital ecosystems.

But how do policy makers in organizations like the Bureau of Land Management (BLM), the U.S. Forest Service (USFS), and The Nature Conservancy know if the steps they take to manage and preserve forests will have the desired effects? Forests grow and evolve on time scales far greater than that of the lives of the people whose job it is to care for them. It may be centuries before the effects of some efforts are fully realized. The uncertainties associated with climate change make it even more difficult to say whether management strategies will prove successful decades or more into the future.

Dr. Robert Scheller, Assistant Professor of Environmental Science at Portland State University, studies forest landscapes, their unique ecologies, and the ways they’ve changed over time. Working in collaboration with scientists and policy makers from around the nation, Dr. Scheller develops computer models that predict the evolution of forests over time taking into account factors like climate change, forest resiliency, and the capacity of ecosystems to adapt to changing conditions. These models provide policy makers key information that can help them determine if specific forest management strategies will be successful in the long run.

“Forest management policies have really long-term effects,” said Dr. Scheller. “Many trees live to be 500 to 1,000 years old. So when forest managers make decisions about planting trees or doing controlled burns, they need to be looking way into the future. Our work helps them do that.”

In California’s Lake Tahoe Basin, Dr. Scheller is involved in an ongoing project sponsored by the BLM through the Sierra Nevada Public Lands Management Act. In this study, Dr. Scheller and his co-P.Is. are examining the effects of fire suppression, wildfires, forest fuel (thinning) treatments, and bark beetle infestations on the long-term potential of the Lake Tahoe forest to sequester carbon.

Given the state of the forest, the study asks, do measures such as controlled burning have net positive or negative carbon footprints? In other words, does burning materials to prevent and/or mitigate fires such as the massive 2007 Angora fire send more carbon into the atmosphere than the forest itself can absorb? If so, would this still be the case if society continues to add carbon dioxide into the atmosphere, perpetuating climate change into the foreseeable future? Using state of the art computer modeling techniques, Dr. Scheller and his colleagues are conducting simulations of predicted changes in climate and ignition patterns and the effects those changes will have on the forest’s ecosystem.

“What we’ve found is that in the short-term fuel treatments in the Lake Tahoe forest add more carbon to the atmosphere,” Dr. Scheller said. “But in the long-term there is an offset that comes from increasing the forest’s resiliency to fire, which in turn leads to fewer major crown fires and thus a net negative for carbon in the future.”

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Half way across the country in northern Minnesota, Dr. Scheller is conducting an ongoing project with collaborators from the USFS and Oregon State University. In the Chippewa National Forests, Dr. Scheller and the research team are compiling multiple maps and datasets detailing factors such as species distribution, forest harvesting, management practices, and others into a single model they will use to conduct simulations forecasting how climate change will affect species and habitat in the forest. When the project is completed, it will provide forest managers with a new tool they can use to develop strategies to protect and preserve the forest and economically important forest product industries threatened by the warming climate in northern Minnesota.

“There are three strategies we have to mitigate the damaging effects of climate change on forests,” Dr. Scheller said. “One is resistance: protecting old growth forests by fighting fires. Then there is resilience, which is the incorporation of practices such as controlled burns to prevent the large fires and help the forest survive smaller fires. And finally, adaption; helping forests adapt to the changing conditions on an accelerated pace. Whatever methods forest managers choose there are effects on the forest.”

Dr. Scheller noted that while this project is focused on the Chippewa National Forest in northern Minnesota, similar projects in forests anywhere could be implemented providing forest managers across the country with detailed, visual model simulations of forest and individual species within those forests reacting to climate change over time.

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Back home in the Oregon Coast Range, Dr. Scheller is working on a project funded by the BLM and the Environmental Protection Agency to study the sustainability of harvesting forest biomass to be used as a source of renewable fuel for electricity generation. 

A visitor to a site in the Coastal Range where lumber has been harvested would likely notice that logging operations leave biomaterial behind: unusable parts of trees and other plant life. Biomass energy companies use this material to make energy and cliam it is a renewable and carbon neutral power source. Supported by funding from the Oregon Department of Forestry, Dr. Scheller and his colleagues are trying to answer questions such as ‘is the carbon added to the atmosphere by using biomass for energy production mitigated by the substitution of biofuel for fossil fuels; and how will the harvest of biofuel change or alter the sustainability of Oregon’s coastal forests?'

“The big question this study is concerned with is from a climate mitigation viewpoint,” Dr. Scheller said. “Is it better to implement forest resistance strategies, try to harvest less and store more carbon in the landscape, or go with the biofuel harvesting and replace and replace some of the burning of fossil fuel?”

The study will assess the trajectories of Oregon’s coastal range forests, the potential for bioenergy supplies, and the opportunities for forest management strategies related to the harvesting of biomass for energy production, all of which will help policy makers in the Department of Forestry plan for a future in which climate change will affect Oregon’s forests which remain a major economic driver in the state’s rural counties.

“One of the major lessons from all of these studies,” Dr. Scheller said, “is that if we move to a low carbon emission trajectory, there are actions we can take to manage the effects of climate change on our forests. But if we continue on a high emissions trajectory, our options become very limited and that would be a bad situation to be in.” 

According to Dr. Scheller, our forests are pretty resilient. History has shown that forests have survived climate change in the past. Droughts and heat waves come and go. But while forests have a natural resilience that land managers can capitalize on, there is a limit to the stress they can take and the carbon they can sequester. Dr. Scheller’s work helps forest managers better understand how best to preserve and protect forests in the face of climate change caused by escalating levels of carbon in the atmosphere.