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Research Highlights - Forest Disturbance Processes

Disturbances to the forest ecosystem structure can be caused by phenomena such as fire, extreme weather (drought, wind, and ice storms),deer overpopulation, and invasive non-native pest species (fungal diseases, insects, and weedy plants), as well as by anthropogenic factors such as global climate change, logging, development, and arson. These can damage or destroy trees and understory plants and change the species distribution and health of plants and animal populations in the forest. Disturbances can have negative or positive effects on the sustainability of various ecosystems, according to the long-term management goals of the land.

2014 Research Highlights

Fewer Pests Found in Wood Packaging Material Following New International Standards

High-risk cargo is unloaded from containers after arrival at US ports of entry and inspected for pests, special inspection warehouses used at the port of Long Beach, California.  Photo by Robert Haack, USDA Forest Service
High-risk cargo is unloaded from containers after arrival at US ports of entry and inspected for pests, special inspection warehouses used at the port of Long Beach, California. Photo by Robert Haack, USDA Forest Service

A new international standard for treating wood packaging material, now in use in international trade for items such as pallets and crating, was first adopted by the world community in 2002. This standard, known as International Standards for Phytosanitary Measures No. 15 (ISPM 15), stipulates how wood packaging material should be treated prior to use in packing goods for export. The United States started requiring foreign countries to comply with ISPM 15 when shipping goods to the United States in 2005. A Forest Service research entomologist and his colleagues found as much as a 52 percent drop in the infestation rate of wood packaging material associated with international imports entering the United States following implementation of ISPM 15. This is encouraging news given that many of our invasive bark- and wood-infesting insects, such as the Asian longhorned beetle and the emerald ash borer, likely entered the U.S. as stowaways in untreated wood packaging from foreign ports. The study – “Effectiveness of the International Phytosanitary Standard ISPM No. 15 on Reducing Wood Borer Infestation Rates in Wood Packaging Material Entering the United States” – was published online in the journal PLOS ONE.

Partners

  • Kerry O. Britton, USDA Forest Service, R&D, Arlington, VA (retired)
  • External partners/collaborators: Eckehard G. Brockerhoff, Scion (NZ Forest Research Institute), Christchurch, New Zealand, and Mark Kimberley Scion, Rotorua, New Zealand; James Turner, AgResearch Ltd., Ruakura Research Centre, Hamilton, New Zealand; Joseph F. Cavey, USDA APHIS, Plant Protection and Quarantine, Riverdale, MD, and Lynn J. Garrett, USDA APHIS, Raleigh, NC; Frank Lowenstein, New England Forestry Foundation, Littleton, MA; Amelia Nuding, National Center for Ecological Analysis and Synthesis, University of California, Santa Barbara; Lars J. Olson, University of Maryland, Agricultural and Resource Economics, College Park; and Kathryn N. Vasilaky, Earth Institute and International Research Institute for Climate and Society, Columbia University, New York, NY

Products & Resources:

Ash at the Confluence of Two Threats: Emerald Ash Borer and Climate Change

Black ash stand in swampy land on the Chippewa National Forest near Cass Lake, Minnesota. Photo  by Louis Iverson, USDA Forest Service
Black ash stand in swampy land on the Chippewa National Forest near Cass Lake, Minnesota. Photo by Louis Iverson, USDA Forest Service

Black ash, a dominant tree species of forested wetlands in Minnesota, Wisconsin and Michigan, provides multiple ecosystem services. It is also a valuable resource for Native American crafters, especially basket-makers. The tree’s existence is threated by the emerald ash borer (EAB), which is killing virtually all ash throughout the Midwest. EAB is now threatening the vast black ash swamps of the Northwoods, and although efforts to slow its spread have been somewhat successful, EAB has not yet been stopped. In addition, climate change impacts models indicate that habitats for black ash will diminish in future decades. Forest Service researchers identified tree species that may be able to replace black ash, including species that could be planted now to ensure that forests remain after EAB damage and after substantial changes in climate have occurred. The models showed that many species currently dominating the Northwoods – quaking aspen, balsam fir, balsam poplar and paper birch – may lose substantial habitat due to warming and varied hydrological conditions, and thus are less suitable as long-term replacement species. Species including American elm, American basswood, red maple, bur oak, and boxelder may be able to colonize areas vacated by the loss of black ash.


Products & Resources:

Municipal Cooperation in Managing Emerald Ash Borer Increases Urban Forest Benefits

A regional plan for managing an EAB infestation of an urban forest greatly improves the percentage of healthy ash trees and the value of their services

Contractors removing trees infested by emerald ash borer, Shields, Michigan.  Photo by David Cappert, Michigan State University
Contractors removing trees infested by emerald ash borer, Shields, Michigan. Photo by David Cappert, Michigan State University

A new analysis of emerald ash borer (EAB) spread in urban forests shows that a regional management and funding strategy would control the infestation more effectively than city-by-city responses or no response. A Forest Service scientist and partners analyzed EAB management plans and budgets for Minneapolis, St. Paul, and 15 Minnesota cities with recent EAB infestations. They projected tree mortality and the costs of tree removals, replacement trees, and pesticide treatments and calculated how trees increase property values. The first scenario assumed none of the cities committed funds and the EAB population spread unmitigated. The second scenario assumed the 17 cities managed the infestation independently with their own city budgets. The third scenario assumed the 17 cities pooled resources to manage the infestation on a regional scale. In the first scenario, removal and replacement costs far exceeded the amount the remaining trees improved property values. The second scenario returned a similar result. When the cities pooled resources in the third scenario, increased property value benefits of the surviving trees far exceeded the costs of treatments, removals, and replacement trees. Comparing the second and third strategies show definitively that regional cooperation and implementation of EAB management greatly improves urban forest benefits.

Partners

  • Kent Kovacs, University of Arkansas, Fayetteville; Rodrigo Mercader, Washburn University, Topeka, KS; Deborah McCullough, Michigan State University

Products & Resources:

Identifying Policy Tools That Encourage Community-Level Defensible Space in Six U.S. Communities

Idaho home with defensible space fostered by an incentive program. Photo by Sarah McCaffrey, USDA Forest Service
Idaho home with defensible space fostered by an incentive program. Photo by Sarah McCaffrey, USDA Forest Service

Numerous factors contribute to whether or not an individual will take action to reduce his or her wildfire risk. When an individual opts to not implement risk mitigation measures, community leaders can use a variety of policy tools to encourage that person to adopt an action or change behavior. These tools included passing rules or regulations, building capacity to act, providing incentives, and establishing community norms. A Forest Service scientist and partners reviewed approaches used by six communities in Idaho, Oregon, and Utah that have been effective at encouraging homeowners to adopt and maintain mitigation activities. Each community’s approach was different. Each was tailored to meet specific community needs, and ranged from collective efforts organized locally to efforts developed externally to provide incentives or potential punishments for not adopting treatments. The most consistent policy tool across communities was capacity building, primarily raising awareness of the fire hazard and potential mitigation behaviors and leveraging external resources, generally obtaining grant funding to assist with vegetation reduction efforts. Another commonality was the involvement of a central group or individual that provided leadership by initiating and championing the mitigation effort and serving as a link to external resources.

Partners

  • Eric Toman and Melanie Stidham, Ohio State University; Bruce Shindler, Oregon State University

Products & Resources:

Restoration of Degraded Northern Forest Stands

Forest Service research informs returning stands with a history of exploitative cutting to sustainable forest management

U.S. Forest Service partnerships with researchers in Canada and elsewhere have led to broad applicability of findings from forest rehabilitation studies and collaborative technology transfer. Photo credit: Daniel Dumais, Quebec Ministry of Natural Resources
U.S. Forest Service partnerships with researchers in Canada and elsewhere have led to broad applicability of findings from forest rehabilitation studies and collaborative technology transfer. Photo credit: Daniel Dumais, Quebec Ministry of Natural Resources

Many forests throughout the United States have a long history of commercial timber extraction. Although forestry research provides a basis for sustainable management, a focus on short-term financial gain often leads to exploitative harvesting in which valuable trees are removed without attention to residual stand condition, often leading to degraded forests with poor composition and vigor. As a consequence, landowners are faced with the difficult task of trying to restore desired attributes to stands with limited production potential. Forest Service scientists are working with researchers and managers in the northeastern U.S. and adjacent parts of Canada to study management alternatives for rehabilitation of degraded stands. Working with university and government partners in the U.S. and Canada, they developed a coordinated program of research and application that informs the restoration of functionality and productivity to forests throughout the region. In addition to workshops, field tours, and webinars in Maine, New York, and Quebec, the group’s work recently served as the basis for a special section on Restoration Silviculture in the Journal of Forestry.

Partners

  • Ralph Nyland, State University of New York: Jeremy Wilson, Harris Center, NH (formerly University of Maine); Mohammad Bataineh, University of Arkansas (formerly University of Maine); Steve Bedard, Francois Guillemette, Patricia Raymond, Stephane Tremblay, and Catherine Larouche, Quebec Ministry of Natural Resources; Jean-Martin Lussier, Canadian Forest Service; Roger Greene at Mason, Bruce, & Girard, Inc., ME.

Products & Resources:

2013 Research Highlights

Defining Light Levels and Light Quality that Minimize Invasive Plant Growth but Promote Oak Growth

Oaks may have an advantage over invasive plants at right ideal light levels and light quality

Japanese stiltgrass leaves grown under 85 micromoles/m2/sec  and a ratio of red to far red light (R:FR) of 0.3 showing physical signs of stress
Japanese stiltgrass leaves grown under 85 micromoles/m2/sec and a ratio of red to far red light (R:FR) of 0.3 showing physical signs of stress

Oak regeneration in eastern forests is dependent on an increase in light to the understory, which is accomplished by harvesting or fire. Unfortunately, these disturbances also promote invasive growth of the nonnatives tree-of-heaven, garlic mustard, and Japanese stiltgrass. Forest Service scientists grew these three invasive species and northern red oak in growth chambers under eight light levels and corresponding light quality, which represented forest light conditions under different management regimes. All three invasive plants showed significantly less shoot growth at lower light levels, roughly equivalent to a forest that had been burned, thinned, or harvested as a light shelterwood (that is, light levels below 180 micromoles/m2/sec and a ratio of red to far red light [R:FR] equal to 0.64). Although adequate oak growth in the field has been achieved at low light levels, the data revealed no patterns in oak shoot growth, possibly due to seed-source effects or root limitations. At low light levels, Japanese stiltgrass exhibited physical signs of stress; its shoot growth levels were lowest and water stress highest. Forest management resulting in low light levels combined with lower light quality may deter growth of invasive plant species.


Surge in red spruce growth following decades of acid deposition-related decline.

Surge could signal a reversal in pollution-related damage due to improved air quality

Healthy red spruce foliage. Photo by Paul Schaberg, U.S. Forest Service
Healthy red spruce foliage. Photo by Paul Schaberg, U.S. Forest Service

Inputs of acid deposition are firmly linked to changes in tree nutrition, reductions in woody growth, and increases in mortality for numerous tree species. In red spruce, broad-scale mortality occurred during the peak of pollution emissions. Acid deposition alters the nutrition of red spruce trees, making them vulnerable to foliar winter injury and loss, and often leading to growth reductions and tree death. Declines in growth also affect the capacity of forests to capture carbon dioxide from the air. Research by a Forest Service scientist and partners documented that a regional 2003 winter injury event reduced the growth of red spruce trees for at least 3 years and estimated that cumulative reductions across the landscape were large. However, researchers were surprised to find that, after growth reduction from the 2003 winter injury, red spruce in New England experienced a dramatic growth increase to levels almost twice the average growth for the last 100 years. New research is examining if recent reductions in air pollution or climate change (warmer winters that reduce foliar injury and extend the growing season) can help account for this remarkable rebound.


Products & Resources:

Data Show Need for Prompt Removal of Dead Ashes

Safety hazards develop quickly from ash trees killed by emerald ash borer

Dead ash trees in a floodplain at Oak Openings Metropark near Toledo, OH. Photo by Kathleen Knight, U.S. Forest Service.
Dead ash trees in a floodplain at Oak Openings Metropark near Toledo, OH. Photo by Kathleen Knight, U.S. Forest Service.

Yearly data collected by Forest Service scientists on thousands of ash trees in emerald ash borer (EAB)-infested sites in Ohio help managers planning their response to EAB in their forests. The dataset, begun in 2005, tracks each individual tree over time to show declining canopy health, EAB symptoms, death, and tree fall. Over 80% of dead ash trees fell within 5 years of dying, with some of them falling much sooner. Recently, this information was used in a plan to remove dying ash trees along trails in an Ohio Department of Natural Resources Nature Preserve to prevent these hazardous trees from falling on people.


Products & Resources:

Role of social factors in wildfire outcomes

Systematic post-fire collection of data on social dynamics during fires improves positive community outcomes

Burned area from the Little Bear Fire near Rudosio, NM. Forest Service scientists and cooperators are developing a research framework that can be used to gather information on social dynamics during and before the fire. Photo by Sarah McCaffrey, U.S. Forest Service.
Burned area from the Little Bear Fire near Rudosio, NM. Forest Service scientists and cooperators are developing a research framework that can be used to gather information on social dynamics during and before the fire. Photo by Sarah McCaffrey, U.S. Forest Service.

To better understand the role of social dynamics before and during a wildfire event in determining outcomes, Forest Service scientists and cooperators are developing a research framework that can be used by researchers and managers to systematically gather information immediately after an event on key social dynamics during and before the fire. This process can help clarify how local context and interactions between diverse factors—from fire management decisions, to homeowner decisions, to communication processes—contribute to positive and negative wildfire outcomes. The consistent methodology developed can be used across multiple fires to improve the ability to learn across events. Over time, this will allow for identification of ways to improve both fire programs and social fire outcomes. The protocol has been refined over the course of two fires in 2012 and two in 2013. Initial findings across fires have identified the importance of pre-fire training amongst emergency responders in fostering relationships that facilitate effective interactions during an event and of open and honest communication with the public not only about what is most directly relevant to them, but also the specific mechanics of fighting a fire.


Products & Resources:

2012 Research Highlights

Modeling Fire in the Continental United States

Map of estimated fire frequency for the historic period 1650-1850.
Map of estimated fire frequency for the historic period 1650-1850.

Knowledge of historic fire frequency is important in guiding restoration of fire dependent ecosystems, but it is often missing or cannot be determined locally due to lack of fire-scar tree records. A Northern Research Station scientist and collaborators have developed a new model called PC2FM that predicts historic fire frequency for the continental United States. The model uses mean maximum temperature, precipitation, their interaction, and estimated reactant concentrations to estimate mean fire intervals. Having science-based estimates of historic fire frequencies for specific project areas is a major advancement in ecosystem restoration. Another important use of the model is in assessing potential changes in climate (temperature and moisture) on the likelihood of wildland fires. The PC2FM model can be used to map large-scale historic fire frequency and assess climate impact on landscape-scale fire regimes

Partners

Richard Guyette and Michael Stambaugh, University of Missouri-Columbia


Impact of Invasive Insects and Fire on Forest Water Resources

A prescribed fire burning in the New Jersey Pinelands. Prescribed fires reduce stand leaf area, resulting in lower evapotranspiration and increased ground water recharge during the following growing season.
Michael Gallagher, U.S. Forest Service
A prescribed fire burning in the New Jersey Pinelands. Prescribed fires reduce stand leaf area, resulting in lower evapotranspiration and increased ground water recharge during the following growing season.

Northern Research Station scientists quantified water use in three representative upland forest stands in the New Jersey Pinelands that were either defoliated by gypsy moth or burned by prescribed fire. Both defoliation and prescribed fire initially had little effect on overall stand biomass but did reduce leaf area, which altered energy partitioning and reduced evapotranspiration. At the landscape scale, defoliation of about 20 percent of the forest increased ground water input by 7 percent. This research indicates that nonstand- replacing disturbances can have significant, but typically short-term, effects on energy partitioning and evapotranspiration at the stand and landscape scales.

Contact

Kenneth Clark

Partners

Rutgers University (Newark and New Brunswick); U.S. Geological Survey


Do Insect-Killed Trees Increase Fire Risk?

Spruce budworm disturbance periodically kills balsam fir, affecting both live and dead fuel loads.
Brian Sturtevant, U.S. Forest Service
Spruce budworm disturbance periodically kills balsam fir, affecting both live and dead fuel loads.

Insect disturbance is thought to increase fire risk by increasing dead fuels across large landscapes. But results from a recent simulation study by Northern Research Station scientists and partners challenge that notion. They applied a landscape succession and disturbance model (LANDIS-II) to evaluate the relative strength of interactions between eastern spruce budworm (a native but destructive insect that feeds on the needles of fir and spruce), vegetation change, and fire disturbances in the Boundary Waters Canoe Area (BWCA) in northern Minnesota. The researchers found that spruce budworm disturbance decreased area burned and fire severity when averaged across 300-year simulations. They concluded that budworm disturbance can partially mitigate longterm future fire risk by periodically reducing live ladder fuels within the mixed forest types of the BWCA, although budworm disturbance will do little to reverse the compositional trends caused in part by fire suppression. These results have important ramifications for both fire mitigation strategies and ecosystem restoration initiatives in the region.

Partners

Bruce Anderson, Superior National Forest; Ellen Bogardus-Szymaniak, TEAMS Enterprise Unit; Douglas Shinneman, U.S. Geological Survey; Peter Wolter, University of Wisconsin-Madison


Predicting Landscape Effects of Forest Mortality Caused by Drought

Leaf scorch and drought symptoms in linden.
Joseph O'Brien, U.S. Forest Service
Leaf scorch and drought symptoms in linden.

Climate change is expected to affect forest landscape dynamics in many ways, but one of the most important direct effects will probably be drought stress. Northern Research Station scientists used weather and Forest Inventory and Analysis (FIA) data to develop equations to predict drought mortality and incorporated them into a landscape forest dynamics model (LANDIS-II). They found that incorporating drought as a tree-killing disturbance does significantly modify forest composition and landscape dynamics. Through model simulations applied to a test landscape in Wisconsin, scientists were able to conclude that, for the Upper Midwest, (1) a drought-induced tree mortality signal can be detected using FIA data; (2) tree species respond primarily to the length of drought events rather than their severity; (3) the differences in drought tolerance of tree species can be quantified; and (4) future increases in drought could bring changes to forest composition.

Contact

Eric Gustafson


2011 Research Highlights

Novel Ectomycorrhizal Fungus Beneficial for Restoration of the American Chestnut in Reclaimed Mined Sites

[photo:] Planting American chestnut on a reclaimed mine site on the Wayne National Forest.  S. Hiremath, photographer.A major problem in reforestation efforts on nutrient-poor abandoned mined lands are the survival and establishment of planted seedlings in the harsh environment. Inoculating seedlings with suitable mycorrhizal fungi can mitigate this problem by providing improved nutrient and water uptake to the seedling. We have identified a novel native ectomycorrhizal fungus associated with American chestnut seedlings that improves their survival and growth in mined lands.

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As part of the American chestnut restoration project, Forest Service scientists have planted thousands of blight-resistant American chestnut seedlings on reclaimed abandoned mined lands in southeastern Ohio. While evaluating various planting protocols, they tested inoculation with several species of ectomycorrhizal fungi (which play a vital role in tree nutrition), including the well-known Pisolithus tinctorius. However, they found that a novel species of ectomycorrhizal fungus belonging to the genus Scleroderma was the most active and effective in the locations tested. This species appeared to be native to the reclaimed mined lands and was aggressive in forming beneficial symbiotic association with chestnut seedlings, even replacing the other species. Identification through DNA sequencing indicated that the novel species was closely related to Scleroderma areolatum and Scleroderma citrinum. This newly identified novel ectomycorrhizal fungus appears to be better suited to form functional mycorrhizae under environmental extremes. Large-scale tests of this fungus for the restoration of chestnut as well as in reforestation efforts on reclaimed mined sites are planned.

NRS Investigator

Shiv Hiremath

Partners

Forest Service Partners:  National Forest System, Wayne National Forest
External partners:  Miami University (Oxford, Ohio)



Reducing Negative Cultural Impacts of Emerald Ash Borer: Saving Black Ash Wood for Native American Basketmakers

[photo:] Technicians tossing a log in a river.  Photo by Therese Polans, US Forest Service Northern Research Station Black ash has great cultural and economic importance in the northeastern United States, especially for Native Americans.  The widespread destruction and removal of black ash in response to an emerald ash borer (EAB) find is a painful prospect for tribes and basket-makers. An innovative collaboration between a Forest Service geographer and entomologist combining traditional knowledge with scientific expertise has found that a traditional practice offers a reasonable solution for those who depend on black ash splints.

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Black ash has great cultural and economic importance in the northeastern and midwestern United States, especially for Native Americans. Widespread destruction and removal of black ash following the discovery of an emerald ash borer (EAB) infestation site is a painful prospect for tribes and basket-makers. Historically, black ash has sometimes been submerged for later use in basketmaking. In a recently completed study, a Forest Service entomologist working with a Forest Service geographer demonstrated that sinking black ash logs in running water for two to three months in the spring kills emerald ash borer larvae and preserves the wood qualities necessary for basketmaking. The scientists worked with a family of basketmakers from the Gun Lake Tribe throughout the research. Additional studies will evaluate submersion during winter months and the impacts of longer term under-water storage on basket-splint quality and color.

 

NRS Investigators

Therese M. Poland and Marla Emery

Partners

Ed Pigeon, Angie Pigeon, and Monte Davis, Match-E-Be-Nash-She-Wish Band of Pottawatomi (Gun Lake Tribe), Michigan 

 



Fireflux Experiments Improve Safety of Prescribed Burns in the New Jersey Pine Barrens

[photo:] Instrumented towers set up within and in the vicinity of prescribed fires in the New Jersey Pine Barrens provide critical meteorological and air quality data for validating smoke prediction tools.  Photo by Nicholas Skowronski, U.S. Forest Service - Northern Research StationPredicting the effects of smoke from low-intensity prescribed fires on local air-quality is being made easier by new tools developed by Forest Service scientists. These tools are now being validated through data collected from fuels, meteorological, and air quality monitoring networks set up near and within prescribed fires in the New Jersey Pine Barrens.  The tools and observational data from this project help fire and forest managers in planning for prescribed burns to minimize adverse air-quality impacts in the vicinity of the burns.

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Prescribed fires are an essential fuels management tool for enhancing ecosystem health and protecting people, homes, and property from wildfires. When prescribed fires are conducted near urban centers or areas where air pollution is already a problem, federal, state, or local air quality standards can be exceeded. Three large fire-fuel-atmosphere interaction (also known as Fireflux) experiments measured fuel loading and consumption, atmospheric turbulence, fluxes of energy, water vapor and CO2, and smoke transport at the landscape scale during operational prescribed fires in the New Jersey Pine Barrens. Results from the experiments indicate that most of the heat and water vapor released from consumed fuel is indeed captured by flux measurements, and that particulate matter (PM2.5) concentrations returned to below EPA standards rapidly after flames passed. Measurements of fuel consumption, fluxes, and atmospheric circulations during fires are essential for evaluating and improving predictive models used by fire and land managers for prescribed burn planning and smoke management.

NRS Investigators

Kenneth L. Clark, Nicholas Skowronski, and Michael Gallagher, Silas Little Experimental Forest, New Lisbon, NJ; 
Warren E. Heilman, Joseph J. Charney, and Xindi Bian, Eastern Area Modeling Consortium, East Lansing, MI; and
John Hom and Matthew Patterson, Newtown Square, PA.

 

Partners

New Jersey Forest Fire Service; New Jersey Department of Environmental Protection; Michigan State University; and Ohio State University.

More information

Clark, K.L.; Skowronski, N.; Gallagher, M.; Heilman, W.E.; Hom, J.  2010.  Fuel consumption and particulate emissions during fires in the New Jersey Pinelands.  3rd Fire Behavior and Fuels Conference, International Association of Wildland Fire, Spokane, WA.  [On CD-ROM].

Heilman, W.E.; Zhong, S.; Hom, J.; Clark, K.; Skowronski, N.; Kiefer, M.; Shadbolt, R.; Bohrer, G.; Bian, X.; Charney, J.J.  2010.  Development and validation of modeling tools for predicting smoke dispersion during low-intensity fires.  3rd Fire Behavior and Fuels Conference, International Association of Wildland Fire Spokane, WA.  (On CD-ROM). (Abstract- pdf - you may download a free pdf reader from Adobe)

Kiefer, M.T.; Zhong, S.; Shadbolt, R.P.; Heilman, W.E.; Charney, J.J.; Bian, X.  2010.  Application of a vegetation canopy parameterization to wildland fire modeling.  29th Conference on Agricultural and Forest Meteorology, American Meteorological Society, Keystone, CO. [Online]. Available: http://ams.confex.com/ams/19Ag19BLT9Urban/techprogram/programexpanded_636.htm



The El Niño Southern Oscillation Modifies Forest Growth Under Elevated Carbon Dioxide and Ozone Levels

[photo:]  Hybrid larch plantation established in 1976 (Riemenschneider & Nienstaedt (1983). Forest Service scientists found that forest responses to climate variability in a future atmosphere with elevated CO2 and ozone levels do not parallel those in the present-day atmosphere.  The relative growth responses to both gasses increased in dry years with high irradiance.  These results suggest that current dynamic global vegetation models, which are used to couple global carbon cycle and climate models, might underestimate forest uptake of CO2 under a changing climate.

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At the Aspen FACE experiment in northern Wisconsin, Forest Service scientists examined 10 years of growth and meteorological data for annual changes in the growth responses of model trembling aspen forests. These forests were grown in natural conditions but exposed to elevated concentrations of atmospheric carbon dioxide and ozone expected in the mid 21st century.  The strongest responses to both gasses (that is, positive growth response to CO2 and negative to ozone) occurred in summers with the least rainfall and the most sunny days, and that were preceded by warm temperatures the previous autumn.  The global climate phenomenon known as El Niño Southern Oscillation (ENSO)is known to influence North American climate for up to six months before and after its peak during North American winter.  Comparison to sea surface temperature data in the tropical Pacific Ocean showed that periodic ENSO cold phase (La Niña) events produced the regional climatic conditions that stimulated forest growth responses to both elevated CO2 and ozone. 

NRS Principal Investigators

Mark E. Kubiske and Paula E. Marquardt, Institute for Applied Ecosystem Studies


2010 Research Highlights

Emerald ash borer damages estimated, biocontrol goes national

[photo:] Contractors removing trees infested by EAB, as part of an early effort to contain outlier populations in Shields, MI (photo by David Cappaert).Emerald ash borer (EAB), a nonnative invasive bark boring beetle discovered near Detroit, MI, and Windsor, Ontario, in 2002, is now found in thirteen states and two Canadian provinces (January 2010). Much of the damage occurs in urban forests. NRS scientists continue to study various aspects of EAB management and control.

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Robert Haight was a member of a working group supported by The Nature Conservancy (TNC) and The National Center for Ecological Analysis and Synthesis that estimated the 10-year costs of ash treatment, removal, and replacement of 38 million ash trees. This number is being used by governmental program managers to justify the benefits of continued EAB research and eradication and treatment programs.  

Leah Bauer, working with many partners, designed a biological control program for management of EAB.  At present, removal of dead trees or insecticide injections of high value trees are the only options available to landowners and municipalities. EAB natural enemies (small parasitic wasps from China) have been released into infested ash stands. These wasps seek and destroy EAB eggs or larvae in ash trees. These parasitoids are now established in areas of Michigan, Ohio, and Maryland. 

Partners

Noel F. Schneeberger, Forest Health Program USFS;  Paul Chaloux, National EAB Program, USDA APHIS; and  Darrell E. Zastrow, Wisconsin Department of Natural Resources.



Climate Change Response Framework project in northern Wisconsin models strategies for preparing for global climate change effects

[photo:] Iconic northern forest scenes such as this one may become more rare as climate change intensifies. The Northern Research Station’s Northern Institute of Applied Climate Science and its cooperators---the Eastern Region, the Chequamegon-Nicolet National Forest, and Northeastern Area State and Private Forestry---have developed an exciting new approach to preparing adaptive strategies for possible global climate changes. Although this project is focused on forests in northern Wisconsin, the participants hope that it will be a model for many regions and ecotypes. The Climate Change Response Framework Project (CCRFP) has reached out to involve not just scientists and organizational stakeholders but private forest landowners, tribal nations, and local governments in the gathering, assessing, synthesizing, and sharing of information. 

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The Climate Change Science Applications and Needs Workshop brought together over 55 experts in climate change science, policy, forest management, and forest ecology to ensure that products from the Climate Change Response Framework incorporate current understanding of the science of climate change, climate change impacts, carbon accounting, and interactions with ecological and social systems. The Shared Landscapes Initiative Workshop brought together 65 participants from across northern Wisconsin to foster dialogue on climate change. They represented federal, tribal, state, and county agencies, non-governmental organizations, universities, and industry groups. The Ecosystem Vulnerability Assessment and Synthesis, a component of the Climate Change Response Framework Project was finalized in the summer of 2010 by an analysis team led by NRS scientist Christopher Swanston. It describes the current landscape and forest types of northern Wisconsin and summarizes projected changes to the climate of northern Wisconsin by 2099.



Carbon and water cycle recovery patterns after disturbance in forest ecosystems

[photo:] A prescribed fire conducted in the Pine Barrens of New Jersey.  NRS-06 researchers are measuring the recovery of carbon and water cycling following fire and insect defoliation in forests in the Pine Barrens.  The recovery of carbon and hydrologic cycling following two major disturbances in pine and oak-dominated stands in the New Jersey Pine Barrens---invasive insect defoliation and fire---are being measured by NRS scientists Kenneth Clark and Nicholas Skowronski

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Both disturbances immediately reduced leaf area in each forest, reducing stand productivity and water use, which then closely tracked the recovery of leaf area.  Understory vegetation played a major role in the regrowth of foliage after each disturbance.  Within 1 year after defoliation or prescribed fire, stands were again sequestering carbon dioxide from the atmosphere.  When integrated over all years measured, both stands approached carbon neutrality within 2-3 years.  Clark and Skowronski’s research has been published in Global Change Biology and will appear in the Journal of Geophysical Research soon. 

Partners

Noel F. Schneeberger, Forest Health Program USFS;  Paul Chaloux, National EAB Program, USDA APHIS; and  Darrell E. Zastrow, Wisconsin Department of Natural Resources.



Hazardous fuel assessments using LIDAR and field measurements

[photo:] A prescribed fire conducted in the Pine Barrens of New Jersey.  NRS-06 researchers are measuring the recovery of carbon and water cycling following fire and insect defoliation in forests in the Pine Barrens.  Lasers, in what is termed Light Detection and Ranging (LiDAR) systems, are being used by NRS researchers Nicholas Skowronski and Kenneth Clark to measure forest structure and canopy fuel loading at the Silas Little Experimental Forest in the New Jersey Pine Barrens.

At left: Light detection and ranging (LIDAR) data showing the cover of understory vegetation at 1 to 2 meter height before and after prescribed fire in the Pine Barrens of New Jersey. Green indicates < 10 % cover, and red indicates > 40% cover.  The area covered by the figures is 9 square-km. 

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These systems can detect and accurately quantify flammable parts of canopy and understory that will burn in wildfires in 1-meter-thick layers.  Currently, they are used to determine hazardous fuel loads around homes and commercial developments. This information can be used to guide risk-mitigation practices and zoning policy and is applicable to any wildland-urban interface area.  Skowronski and Clark’s research will appear in Remote Sensing of Environment soon, and researchers at the Silas Little EF have recently received a grant from the Joint Fire Sciences Program to validate crown fuel estimates made using LIDAR technology. 


2009 Research Highlights

Biomass utilization

[photo:] Value-added products such as flooring utilize small-diameter material toproduce jobs important to community sustainability.“If only there was a use for small-diameter woody material…” is a lament heard throughout the forested United States. People view biomass utilization through a multi-faceted lens: as a step in the quest for energy independence; as a tool for economic revitalization; as a way of reducing wildfire risks; or as a means of improving ecosystem health.

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What is standing in the way to achieving any of these worthy goals through biomass utilization? NRS scientists Pamela Jakes and Sarah McCaffrey assisted partners who examined 10 Federal biomass projects throughout the country with these questions in mind. They found that transportation cost is one of the major barriers to biomass utilization, along with the perceived low value of biomass, lack of value-added product options, and environmental concerns. In communities where the projects were located, people overwhelmingly supported the development of small-scale technology to increase biomass utilization. Small-scale projects for energy generation and for production of animal bedding, flooring, and related goods were seen as more viable than large-scale projects because of the size and types of local markets, required capital investment, available workforce, and increased social acceptance for smallscale use. Of particular interest is the development of local industries that produce value-added products and keep the economic benefits in the local community.

Partners

  • Dennis Becker, University of Minnesota
  • Kathleen Halvorsen, Michigan Technological University
  • Cassandra Moseley, University of Oregon


Restoring the American chestnut

[photo:] Pollination of one of the few remaining American chestnuts in Vermont, an attempt to capture genes from locally adapted, cold-tolerant native trees.The American chestnut was a key forest tree species in eastern North America and new research may help return this species to forests. A fungal blight that spread across eastern North America about 100 years ago killed almost all American chestnut trees and eliminated them as a dominant forest species.

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The fungus that caused the blight was first brought into the U.S. from Asia and it still persists in sprouts from living stumps and root systems of otherwise-dead native chestnuts. The American Chestnut Foundation® (TACF) is leading a partnership with the Northern Research Station and other institutions to selectively breed blight-resistant chestnut. Recent testing by NRS scientist Paul Schaberg and researchers at the University of Vermont has focused on the survivability of the TACF hybrid/backcross stock in the northerly portion of the original range of American chestnut. One study showed that American chestnut seedlings were less tolerant of cold and were more prone to freezing injury and dieback of terminal shoots. In another study, the nuts of American chestnut were also found to be prone to injury if not protected from subfreezing temperatures. New studies are investigating ways in which the cold tolerance of nuts and shoots can be bolstered through genetic selection and management practices.

Partners

  • The American Chestnut Foundation
  • The University of Vermont


Preventing the spread of invasive insects

[photo:] Ash firewood enclosed in a double plastic bag to prevent live emerald ash borer from being transported; all adult beetles that emerged from the firewood died inside the plastic bags.Wood products—especially wood packaging materials and firewood—have been identified as important pathways for the movement and introduction of invasive insects, particularly bark beetles and wood borers. Two recent invasive insects, Asian longhorned beetle (ALB) and emerald ash borer (EAB), were probably introduced and transported this way.

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NRS researchers Therese Poland and Melody Keena explored innovative treatments for killing the insects while inside of various wood products. One treatment, proposed as a potential replacement for fumigation or heat treatment, is using vacuum to desiccate the insect larvae. The other treatment, proposed to prevent escape of invasive species from firewood (which is often moved without any treatment), is double-bagging with large plastic bags such as garbage bags, until the insects have emerged and died inside the bags. The use of vacuum treatments to kill ALB and EAB larvae and bagging firewood with plastic bags to prevent escape and spread of EAB were effective.

Partners

  • Zhangjing Chen and Marshall White, Virginia Tech University
  • Deepa Pureswaran, Canadian Food Inspection Agency
  • Andrea Diss-Torrance, Wisconsin Department of Natural Resources


Preservation of lingering ash trees

[photo:] Grafting a bud from 'lingering ash' onto rootstock.Reports following the outbreak of the emerald ash borer (EAB) indicated that there was no resistance to this insect in the Detroit area, where ash was a popular street tree. As the beetle spread away from urban areas into more genetically diverse native stands and woodlots, NRS researchers Jennifer Koch, Kathleen Knight, and Therese Poland, along with a partner, established plots to monitor the impact of EAB in these areas.

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More than 3,000 ash trees in infested forests in Michigan and Ohio have been monitored yearly using a canopy health index. Almost all of the ash trees are dead, however these inventories have identified a small number of trees that have persisted. Data collected in 2009 showed that about 1.0% of the ash trees have remained alive and that 0.1% retained a healthy crown appearance. Even if these trees ultimately succumb to EAB, the traits that helped them survive longer may be helpful in breeding ash trees that could resist EAB. Forest Service researchers and collaborators are working quickly to preserve these “lingering ash” so tests can be performed to determine what mechanisms that allow them to survive.

Partner

  • Dan Herms, Ohio State University, OARDC


Planning wildlife conservation in large landscapes

Wildlife conservation and management practices have traditionally used site-level approaches, but now, largerspatial- scale efforts are needed. NRS scientists have been at the forefront of developing these larger-scale models. Spatially explicit information on habitat requirements, land use, and vegetation composition and structure now make it possible to model habitat dynamics of larger landscapes.

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The book Models for Planning Wildlife Conservation in Large Landscapes, published in 2009 and edited and compiled by NRS scientist Frank R. Thompson, III, and a colleague, Joshua Millspaugh, consolidates conceptual basis and practical approaches to modeling and conserving wildlife in large landscapes. The book is divided into three sections. The first includes chapters that address critical concepts to consider in large-scale conservation activities. The second includes chapters reviewing available modeling approaches. The last component includes chapters integrating theory and methods as a series of case studies from diverse ecosystems and for multiple wildlife species. The book is available from Academic Press.

Partners

  • Seventy authors from universities, state and federal agencies, industrial landowners, private consulting firms, and nongovernmental organizations contributed to the 24 chapters in this book.


2008 Research Highlights

Treated wood packing material could still harbor invasive insects

[image:] Wood packing materialThe international community attempted to stem the spread of invasive species in 2002 by adopting international standards for treating wood-based packaging materials, such as pallets and shipping crates.  However, Robert Haack, a Northern Research Station scientist and a cadre of international researchers have demonstrated that insect borers could infest such packaging material, even after treatment, especially when bark was present.

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Researchers conducted field and laboratory studies and discovered that the shape and size of bark patches left on packaging materials impacted the colonization and development of insects.  Using their findings, the international standard for wood packaging is now being revised to require removal of any bark patches that are wider than three centimeters and exceed 50 square centimeters in surface area.

These bark tolerance limits are now being considered by individual countries worldwide.  If adopted by the world community through the International Plant Protection Convention, these revised packaging standards should significantly reduce the spread of invasive insects through wood packaging materials. More>>

Partners

  • Michigan State University
  • APHIS
  • Department of Homeland Security-Customs and Border Protection


Studies lessen guesswork in monitoring for emerald ash borer outbreaks

[image:] Adult emeral ash borerThe emerald ash borer has killed or damaged more than 25 million ash trees in North America since its detection in 2002. One of the problems in stopping the invasive Asian insect is that by the time it’s detected in an area, it’s often too late to save its victims. Northern Research Station scientists are taking some of the guesswork out of predicting where the beetles might strike next.

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Researchers have developed a method of using past beetle travel patterns to calculate the risk of colonization at new locations. The resulting maps can help land managers with limited time and resources better target where they’ll focus monitoring efforts.

Once a monitoring site is selected, a second study could help researchers refine which trees they investigate. Scientists discovered that the emerald ash borer has an order of preference in which species it will infest, such as choosing green ash over blue ash, while avoiding non-ash species altogether.

As scientists gain a better understanding of the ash borer’s preferences and movements, they can continue to fine tune monitoring strategies and defense mechanisms to hopefully stem the tide of an otherwise undeterred invader. More>>


New fire-weather index anticipates atmospheric turbulence, erratic fire behavior

[image:] clouds above pine treesFighting wildfires can be risky business. Even under the most controlled situations, trouble can literally blow in without warning. Sudden gusts of wind from varying directions can radically change the direction and behavior of a fire, threatening property and lives.

Researchers from the Northern Research Station have developed a weather index that measures the likelihood of trouble brewing overhead. Using weather software that predicts temperatures and wind speeds near the ground and higher in the atmosphere, scientists can calculate the amount of turbulent energy, an indicator of erratic wind gusts that might be present near the ground.

Experimental hourly predictions of the turbulence-based fire-weather index are available from the Forest Service’s Eastern Area Modeling Consortium at www.nrs.fs.fed.us/eamc/current/experimental/, where fire managers can test the effectiveness of the new index for pinpointing when and where the atmosphere could contribute to erratic fire behavior. Simulations in the western Great Lakes and Northeastern U.S. are yielding promising results.

Partners

  • Eastern Area Modeling Consortium
  • Silas Little Experimental Forest


Fungi help American chestnut reclaim habitat

[image:] Two people planting a chestnut seedling in OhioA fungal disease nearly decimated the American chestnut population by 1940. Now a different fungus is helping the tree reestablish itself in its native territory.

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Northern Research Station scientists recently planted 750 blight-resistant American chestnut seedlings within the Wayne National Forest in Ohio. Their site selection, however, was somewhat unconventional: an abandoned, burnt out coal mine. To help the seedlings establish themselves in such a nutrient-poor environment, scientists inoculated them with mycorrhizal fungi, to counterbalance the area’s soil deficiencies.

The success of this project can provide land managers with a novel strategy for reforesting reclaimed lands with compromised soil value while also restoring a national treasure.

Partners

  • The Ohio University
  • American Chestnut Foundation
  • Ohio Department of Corrections
  • Boy Scouts of America and
  • Wayne National Forest


Map forecasts shifting populations into forested areas

[image:] House in a forested area, with a bulldozer int he foregroundResidential development, once concentrated in metropolitan areas, has spread across the landscape and into fire-prone wildlands, creating a serious problem to protect people and property from this natural process of forest ecosystems. Solutions to this problem start with measuring the extent of population shifts into the Wildland Urban Interface (WUI).

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Experts in landscape ecology and rural demography teamed up with Northern Research Station scientists to analyze geographic and ecological databases from rural landscapes and combined them with U.S. Census Bureau data to map where people live near or within forested lands. Their national WUI map is a widely-used policy and management tool and indicates that one-third of all U.S. homes are located in this zone. Looking ahead to the year 2030, researchers expect steady housing growth in the West and Southeast, regions especially prone to human disturbances from wildland fire and introduction of invasive species.

These newly acquired projections give policymakers and resource experts the opportunity to anticipate and prepare for many different human impacts on ecosystem structure and function. WUI and housing growth maps, statistics and GIS data for download can be found at http://silvis.forest.wisc.edu/maps.asp.

Partners

  • University of Wisconsin-Madison
  • Oregon State University
  • Pacific Northwest Research Station
  • Rocky Mountain Research Station
  • The Wilderness Society


Model suggests strategies to balance human development with ecosystem function

[image:]  Example fire probability map showing the spatial pattern of fire risk generated for the Lakewood study area, part of the Chequamegon-Nicolet National Forest. Wildland-Urban Interface is cross-hatched in black.As the U.S. population continues to shift into remote areas adjacent to public lands, greater pressure is put on land managers to be mindful of their new neighbors while still maintaining the ecosystems in their charge. Humans both increase fire ignitions and depend on public agencies for fire protection. However, because fire-dependent ecosystems are often more flammable than other forest types, forest managers must find ways to balance human safety with ecosystem management goals.

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Northern Research Station scientists worked with resource specialists from Wisconsin’s Chequamegon-Nicolet National Forest to evaluate fire mitigation strategies that account for the needs of nature and the activities and safety of neighbors. A forest simulation program that accounts for fire risks from humans allowed managers to test various mitigation strategies, such as bans on debris burning and location of fire-resistant tree species, to see how each strategy affected their overall management objectives.

Newly developed rural population projection maps were also used to determine which remote locations were most likely to be developed in the study area. Alternative future development patterns are currently being integrated into the simulation program to evaluate potential fire risk and forest management options in the face of anticipated development patterns.

The success of these modeling options may pave new and innovative ways for land managers to maintain fire-dependent ecosystems while reducing conflicts with existing and future human neighbors. More>>

Partners

  • University of Missouri-Columbia
  • Oregon State University
  • Conservation Biology Institute
  • U.S. Forest Service

2007 Research Highlights

Improving gypsy moth containment methods

[image:] Map shows gypsy moth spread in north central U.S.NRS entomologists and colleagues generated a clearer understanding of why the gypsy moth expands its range in periodic pulses, due to an Allee effect, and demonstrated how the rate of spread was related to the strength of these Allee effects.

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This knowledge will help forest managers fine tune the Slow-the-Spread program, which seeks to identify and suppress population peaks along the gypsy moth expansion front to slow the rate of spread to uninfested forests.

Partners

  • Slow-the-Spread Foundation
  • U.S. Forest Service: State and Private Forestry – Forest Health Protection


Engaging the public in support of fire mitigation efforts

[photo:] home in the woods near Mack Lake, MichiganThe public plays an integral role in effective fire management by supporting efforts to reduce fire hazard on public lands (thinning and prescribed fire) and by decreasing fire risk on their property (defensible space) and within their community.

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Through studies in different areas of the nation, NRS researchers found that 60 to 80 percent of the population supports both thinning and prescribed burning as management tools to reduce fire risk and a majority engage in defensible-space activities. Researchers also confirmed that the most effective means of increasing public acceptance is an interactive one that allows managers to better understand key local concerns and establish trust, while allowing individuals and communities to clarify misconceptions.

Partners

  • Michigan State University
  • Oregon State University
  • Cornerstone Strategies
  • University of Massachusetts
  • University of Minnesota
  • University of Florida


Trees need calcium supplements too

[photo:] shows tree wound on sugar mapleNRS researchers demonstrated that restoring calcium levels in sites affected by acid rain-induced nutrient leaching has positive effects on the health of red spruce and sugar maple. Because calcium is essential to tree health, protracted loss of this nutrient from forests reduces tree health and productivity.

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These species are important in northern forest ecosystems and to rural economies. In red spruce, calcium restoration resulted in a dramatic reduction of foliar and bud freezing injury during the severe winter of 2003-04. For sugar maple, calcium restoration resulted in significant increases in growth and vast improvements in stem wound closure. This is particularly important to sugar maples, which are wounded annually to collect maple sap for maple syrup.

Partner

  • University of Vermont


Biological control offers hope for management of emerald ash borer

[photo:] EAB predatorNRS scientists implemented the first field releases of stingless wasps that may provide biological control of the emerald ash borer (EAB), an invasive pest that is killing the ash trees in North America. EAB was discovered in Michigan and Ontario in 2002 and has since spread to Ohio, Indiana, Illinois, Maryland, Virginia, Pennsylvania, and West Virginia.

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Genetic comparisons by NRS research entomologists revealed that China is likely the country of origin for this destructive beetle. In northeast China, they discovered two new natural enemies specific to EAB – tiny wasps that parasitize and kill EAB eggs and larvae. After permits were issued in July 2007, NRS scientists released these parasitic wasps in four EAB-infested field sites as part of their ongoing search for tools to manage EAB populations.

Partner

  • Michigan State University


Oak wilt risk analysis helps keep Wisconsin forests healthy

NRS scientists developed a simple risk analysis methodology that helps prevent introduction and subsequent spread of an established invasive pathogen, the oak wilt fungus, in forest stands.

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This method is the basis of statewide guidelines for timber harvesting activities in Wisconsin oak timberlands and should reduce the risk of oak wilt introduction and spread.

Partner

  • Wisconsin Department of Natural Resources