USDA Forest Service

Pacific Northwest Research Station

Pacific Northwest Research Station
333 SW First Ave.
Portland, OR 97204

(503) 808-2100

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» Alaska Research

LIDAR estimates biomass supply

LIDAR sampling. Photo credit: Hans Andersen

Remote rural communities in interior Alaska generally rely on fossil fuel to meet their power and heating needs. Diesel prices increased 83 percent from 2000 to 2005, however, and utility costs can amount to more than a third of a household’s income.

Wood-based energy may be an alternative, but estimates of available forest biomass are needed before comprehensive plans for bioenergy production can be developed. Because interior Alaska has few roads, much of the data on biomass availability is collected by aircraft equipped with LIDAR (airborne laser scanners). Researchers tested the precision of this data by pairing it with data from sparse field plots. The results were successful and within an 8 percent level of precision.

This study indicates that airborne LIDAR sampling can be useful in planning bioenergy development in interior Alaska.

Contact: Hans Andersen,


Fungi may help seedlings regenerate

Postfire establishment of tree seedlings.Photo credit: Teresa Hollingsworth

Mycorrhizal fungi on roots of tundra shrubs may facilitate postfire establishment of tree seedlings. Understanding the complex mechanisms controlling treeline advance or retreat has important implications for projecting ecosystem responses to direct and indirect effects of global environmental change. A warming climate not only promotes growth of seedlings and mature trees, but also enhances disturbances such as fire, leading to further seedling establishment.

Synergistic activity between resprouting tundra shrubs and newly established seedlings after fire could either maintain boreal community dynamics at the limit of tree establishment or provide a mechanism for expansion under future scenarios of warming and fire.
Land and fire managers are using these results to help predict future successional trajectories in treeline and tundra ecosystems. Modelers are using these results to more accurately model mechanisms that limit and facilitate tree migration into previously unoccupied areas.

Contact: Teresa Hollingsworth,


Hope remains for polar bear habitat

Wildlife biologist Bruce Marcot is placing a radio collar on a cub.Photo credit: Steve Amstrup

No “tipping point” has been reached or is foreseeable for polar bear sea ice habitat over the next century, researchers determined. If global greenhouse gas levels are reduced, polar bear populations could be maintained or recovered. This work continues research that led the U.S. Fish and Wildlife Service (USFWS) to list the polar bear as a threatened species in 2008. The analysis indicates that only major mitigation of greenhouse gases will limit sea ice loss and reduce the probability of polar bear populations becoming more vulnerable.

This research indicates that that current sea ice loss resulting from climate change may still be reversible, providing new hope for conserving polar bears. This information can be used by the USFWS to help develop recovery actions for polar bears. The research appeared as the December 2010 cover story in Nature.

Contact: Bruce Marcot,


Yellow-cedar trees dying in Alaska

Yellow-cedar trees in Alaska.Photo credit: Paul Hennon

Yellow-cedar, a culturally and economically valuable tree in southeastern Alaska and adjacent parts of British Columbia, has been dying off across large expanses of these areas for the past 100 years. The cause of the tree death is now known to be a form of root freezing that occurs during cold weather in late winter and early spring, but only when snow is not present on the ground. The snow protects the fine, shallow roots from extremely low soil temperatures.

Scientists are working with partners in the Alaska Region of the Forest Service to use this new information as the framework for a comprehensive conservation strategy for yellow-cedar in Alaska in the context of a changing climate. The research findings are featured as a cover story in the February 2012 issue of BioScience.

Contact: Paul Hennon,



Featured Scientist

Theresa HollingsworthTeresa Hollingsworth is a Fairbanks-based research ecologist who studies the boreal forests of Alaska’s vast interior. Although these forests, consisting mainly of black spruce communities, cover great expanses of land, relatively little is known about their basic ecology.

Hollingsworth’s research is helping to reveal what influence environmental factors have on the composition of these communities. In one study, for example, she named and described three black spruce plant communities and five subtypes, connected their composition to environmental gradients—the first community classification of its kind in the region. Hollingsworth is currently investigating whether fire, common in the interior during the summer months, weakens the relationship between environmental factors and black spruce community dynamics.

Contact her at


Tools and Software

e-Reader editions of Science Findings now available


This month, the station launched e-Reader-friendly versions of recent issues of the popular Science Findings series. The June through November 2011 issues are now available in both .ePub and .mobi formats, making them compatible with a wide variety of mobile devices. More recent issues of the series will be available soon. PNW is the first Forest Service research station to produce e-Reader versions of its printed publications. Learn more.

US Forest Service - Pacific Northwest Research Station
Last Modified: Tuesday,05August2014 at09:40:45CDT

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