You are here: NRS Home  / Research Programs / Forest Disturbance Processes / Invasive species / Research Highlights

Research Highlights - Invasive Species

Dutch Elm Disease. Chestnut Blight. Emerald ash borer.  While they are iconic examples of non-native, or exotic, forest diseases and pests, they are hardly alone.

More than 400 species of non-native invasive forest insects and diseases have become established in the United States, many in the last 100 years. While some have had little effect on forests, others have spread rapidly and caused economic and ecological damage to forests and urban trees.

Because Northeastern and North Central cities have historically been entry ports for invasive pests, Northern Research Station (NRS) entomologists and plant pathologists have a long history of research on the biology and ecology of non-native forest pests as well as on methods for control and eradication. Work by NRS scientists is contributing to better understanding of tree diseases and development of management strategies and planning tools for achieving the goal of healthy woodlands, forest plantations, and urban landscapes.

Risk, Detection, and Spread

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:

Asian Longhorned Beetle Traps Now Being Trialed in 14 States and 3 Countries

Checking an Asian longhorned beetle trap. Photo by Melody Keena, US Forest Service NRS.

Checking an Asian longhorned beetle trap. Photo by Melody Keena, US Forest Service NRS.

The most effective trap and lure combination (male pheromones and plant volatiles) developed and tested for 3 years at the Worcester, MA, Asian longhorned beetle infestation site is now being trialed in 14 states and 3 other countries. Research to refine the lures continues, but the current lure has proven useful enough to allow other groups to try it out this year. Successful trapping of ALB both where infested trees were still suspected to exist and in areas that had not yet been surveyed in the Worcester, MA, quarantine zone are helping the program to pinpoint lingering populations and know where to intensify surveys to find additional pockets of beetles. Currently, traps are being placed by 9 arboreta in the Sentinel Plant Network (including the National Arboretum), groups in Italy, Switzerland, and the United Kingdom, and in 13 states by state or federal agencies. In addition to the collaborators’ time and resource inputs, funding for this work has come from Forest Service Forest Health Protection, the Horticultural Research Institute, and the Alpha Wood Foundation. In 2012, a workshop and subsequently a webinar trained people in use of the traps.

Contact

Melody Keena, Research Entomologist and Talbot Trotter, Research Entomologist

Partners

Rick Turcotte, Kevin Dodds, and Michael Bohne, US Forest Service State & Private Forestry/Northeastern Area, Forest Health Protection; Maya Nehme, Peter Meng, Kelli Hoover, Consuelo De Moraes, Mark Mescher, and Thomas Baker, Pennsylvania State University; Aijun Zhang, USDA Agricultural Research Service; Alan Sawyer, USDA Animal Plant Health Inspection Service Center for Plant Health Science Technology; Clint McFarland, APHIS Massachusetts Asian Longhorned Beetle Eradication Program; and Julie Coop, Massachusetts Department of Conservation and Recreation

More Information

Asian longhorned beetle - Adult Trapping System

Nehme, Maya; Keena, Melody; Zhang, Aijun; Sawyer, Alan; Hoover, Kelli. 2011.Monitoring Asian longhorned beetles in Massachusetts. In: McManus, Katherine A; Gottschalk, Kurt W., eds. 2010. Proceedings. 21st U.S. Department of Agriculture interagency research forum on invasive species 2010; 2010 January 12-15; Annapolis, MD. Gen. Tech. Rep. NRS-P-75. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station: 109-110.


Balanced Approach to Surveillance Reduces the Costs of Invasive Species Detection and Control

Gypsy moth trap used to detect new populations

Gypsy moth trap used to detect new populations. Photo by William A. Carothers, USDA Forest Service, Bugwood.org

Invasive species threaten ecosystem stability worldwide and inflict sizable economic damage, including expenditures for control and losses of market and non-market benefits. Enhanced efforts to detect and eradicate newly established species are critical to reducing their ecological and economic harms. Cost-effective detection programs must balance the intensity and cost of detection with the costs of eradicating newly detected populations. In addition, surveillance programs are usually applied in environments under continual invasion pressure where the number, size and location of established populations are unknown prior to detection. Northern Research Station scientists and an international team of partners developed a new planning tool that accounts for these features of the decision and invasion environment. It helps design long-term surveillance programs for high-concern invasive species to minimize the total costs of preventing their long-term establishment and spread. The tool helped evaluate the surveillance program for gypsy moth in California. They found that allocating surveillance effort across counties in proportion to surveillance cost and gypsy moth establishment rate could save the state over $200,000 annually in surveillance and eradication expenditures.

Contact

Robert Haight, Research Forester

Partners

Rebecca S. Epanchin-Niell, Resources for the Future, Washington, DC; Ludek Berec, Biology Centre of the Academy of Sciences of the Czech Republic, Branisovska; John M. Kean, AgResearch Lincoln, New Zealand

 

More Information

Epanchin-Niell, R.S.; Haight, R.G.; Berec, L.; Kean, J.M.; Liebhold, A.M. 2012. Optimal surveillance and eradication of invasive species in heterogeneous landscapes. Ecology Letters 15: 803–812. 


The FRAME Study in Delaware

Frame study in Delaware Banded wood thrush

Frame study in Delaware Banded wood thrush.

This research addresses a widely recognized problem – invasive nonnative plants – in terms of the overall ecology of urban forest fragments. Beginning in 2009, Northern Research Station scientists characterized 21 sites in northern Delaware ranging from 2.1 to 16 ha in size, starting from soil analyses and working up through litter, understory plants, arthropods, reptiles, amphibians, and birds. A unique aspect to this research is that it is informed by work begun in the 1960s in some of the same patches, by the same two research entities (the Forest Service and the University of Delaware). The 1965 report was prescient in its recognition of urban forest benefits, ranging from mental health to clean air and water. Just 2 years into the project, scientists are finding profound changes in the density of nonnative plant species in the understory, their relationship to native songbird habitat use, and their connection to underlying soil conditions. The coastal mid-Atlantic region is a hotspot for these issues because of its long history of settlement, population density, value to migrating birds, and moderate climate.

Contact

Vincent D'Amico, Research Entomologist

Partners

The University of Delaware, and the state of Delaware, New Castle County, and the city of Newark, DE.

More Information

FRAME ( Forest FRAgments in Managed Ecosystems)

D'Amico, Vince; Shriver, Greg; Bowman, Jake; Ballard, Meg; Wiest, Whitney; Tymkiw, Liz; Miller, Melissa. 2011. Multitrophic effects of calcium availability on invasive alien plants, birds, and bird prey items. In: McManus, Katherine A; Gottschalk, Kurt W., eds. 2010. Proceedings. 21st U.S. Department of Agriculture interagency research forum on invasive species 2010; 2010 January 12-15; Annapolis, MD. Gen. Tech. Rep. NRS-P-75. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station: 82.


New Fungus Kills Hickories

Rapidly declining crown of bitternut hickory in Wisconsin. Photo by Jennifer Juzwik, US Forest Service NRS.

Rapidly declining crown of bitternut hickory in Wisconsin. Photo by Jennifer Juzwik, US Forest Service NRS.

Periodic episodes of widespread and severe crown decline and mortality of smooth-bark hickory trees have occurred in the north central and northeastern United States since the early 1900s. Historically, this problem has been attributed to hickory bark beetles and drought. However, a Northern Research Station scientist, in collaboration with the University of Minnesota, found that the most common scenario in six states of the region involves the synergistic interaction of the hickory bark beetle and a newly discovered fungus species (Ceratocystis smalleyi) producing rapid crown decline and death of bitternut and pignut hickory trees. All of the hickory trees in a 5- to 10-acre stand or a portion of a larger stand may die within two years of symptoms first appearing. Hundreds of bark cankers caused by the fungus occur on main stems of declining trees, which also have hundreds to thousands of hickory bark beetle attacks. Fungus infection of the outer wood results in reduced rate of sap flow in trees with numerous cankers, followed by decreased water transport and rapid crown decline. The fungus is likely native to the region but escaped detection for many decades. The bark beetle provides the wound for fungus infection and likely serves as the primary vector.

Contact

Jennifer Juzwik, Research Plant Pathologist, and Ji-Hyun Park, University of Minnesota

Partners

L. Haugen, S. Katovich, and M. Mielke, US Forest Service State & Private Forestry, Northeasern Area; J.-H.Park and J. Cavender-Bares, University of Minnesota; J. Hietpas, Stockbridge-Munsee, Mohican Nation, Bowler, WI; B. Stempa, U.S. Bureau of Indian Affairs, Bowler, WI; M. Pecore, Menominee Tribal Enterprises, Keshena, WI; state departments of natural resources in Indiana (P. Marshall), Iowa (T. Feeley), Minnesota (E. Hayes), Ohio (J. Puperi), and Wisconsin (K. Scanlon); J. Graham, New York Department of Conservation; D. Richardson, Chippewa County Forest, WI; J. Hickey, Private Landowner, Hatley, WI


Plant Imports Cause Forest Pest Invasions

Trade in live plants is an important invasion pathway for non-native forest pests worldwide. Such pests can have severe economic and ecological consequences. Nearly 70 percent of damaging forest insects and pathogens established in the United States between 1860 and 2006 most likely entered on imported live plants. The current regulation of plant imports is outdated and needs to balance the impacts of pest damage, the expense of mitigation efforts, and the benefits of live plant importation. To inform these discussions, we document large increases in the volume and value of plant imports over the past five decades and explain recent and proposed changes to plant import regulations. Two data sources were used to estimate the infestation rate of regulated pests in live plant shipments entering the nation, thus allowing evaluation of the efficacy of the current port inspection process.

Contact

Andrew Liebhold, Research Entomologist

Partners

Kerry Britton, US Forest Service Forest Pathology Research, Research & Development; Eckehard Brockerhoff, Scion/New Zealand Forest Research Institute; Lynn Garrett, USDA APHIS CPHST; and Jennifer Parke, Oregon State University

More Information

Liebhold, Andrew M.; Brockerhoff, Eckehard G.; Garrett, Lynn J.; Parke, Jennifer L.; Britton, Kerry O. 2012. Live plant imports: the major pathway for forest insect and pathogen invasions of the US. Frontiers in Ecology and the Environment. 10(3): 135-143.



Examining the Movement of an Invasive Weevil Using the Stable Isotopes of Carbon

Polydrusus sericeus, a non-native weevil found in the northern hardwood forests of Wisconsin and Michigan. It feeds on the leaf margins and fine roots of hardwood tree species. Photo by Joanne Lund, US Forest Service NRS

Polydrusus sericeus, a non-native weevil found in the northern hardwood forests of Wisconsin and Michigan. It feeds on the leaf margins and fine roots of hardwood tree species. Photo by Joanne Lund, US Forest Service NRS

Stable carbon isotopes are naturally occurring elements with alternate forms and nuclear masses; as they vary in abundance during carbohydrate fixation in plants, and are useful as tracers in the ecological study of insect herbivores. At the Aspen FACE experiment in northern Wisconsin, mixed tree communities were grown under four air-quality treatments: elevated carbon dioxide, elevated ozone, elevated carbon dioxide plus elevated ozone, or ambient air.  Northern Research Station scientists used the unique signature of the carbon dioxide fumigation gas as a tracer to determine the source of naturally occurring populations of nonnative invasive weevils (Polydrusus sericeus) that were collected by sweep nets in the experimental rings.  Individuals from the well-established weevil populations moved infrequently in and out of the treatment rings.  Changes in weevil nitrogen content may imply changes in food quality as a consequence of air pollution. That is, leaf nutrition is lower when ozone concentration is higher, and the insect may eat more to compensate for poor quality food. The dispersal patterns can be used to determine source populations and predict future movement, helping land managers in controlling the spread of invasive species across northern hardwood species.

Contact

Paula Marquardt, Research Plant Geneticist and Joanne Lund, Biological Science Lab Technician

Partners

William Mattson, emeritus, US Forest Service Northern Research Station

 

More Information

Tracing the movement of an invasive insect using stable isotopes

Marquardt, P.E.; Lund, J.N.; Mattson, W.J.  You are what you eat: stable isotopes and plant-herbivore interactions under elevated carbon dioxide and ozone. In: Proceedings, Annual Meeting of the American Society of Plant Biologists; 2011. August 6-10; Minneapolis, MN.

Lund, Joanne; Marquardt, Paula; Mattson, William Jr. 2010. Analyzing the movement of an invasive weevil (Polydrusus sericeus) using stable Isotopes. In: 95th Ecological Society of America annual meeting; 2010 Aug 1-6; Pittsburgh, PA. Abstract.


Biology and Ecology

The 1000-Species Fungal Genome Project

Dan Lindner and Jessie Glaeser working at the PCR machine in the Center for Forest Mycology Research, Madison, WI.  Photo Credit: Stephen A. Schmieding, staff photographer, Forest Products Laboratory
Dan Lindner and Jessie Glaeser working at the PCR machine in the Center for Forest Mycology Research, Madison, WI.  Photo Credit: Stephen A. Schmieding, staff photographer, Forest Products Laboratory

Fungi are essential to forest health and human activity. In the forest, they are involved in nutrient recycling and carbon sequestration of woody debris; they form beneficial networks with tree roots that assist in nutrient uptake; and they can cause disease and tree death.  In the human sphere, fungi are necessary for making beer, yeast bread, and many cheeses; mushrooms (especially truffles) are gourmet delicacies. However, many aspects of fungal physiology and genetics are barely understood. Only 10 percent of fungi have been described scientifically and only about 100 fungal species have been fingerprinted by total DNA sequencing. In an effort to better understand Kingdom Fungi, a 5-year international project has been launched that will develop total DNA sequences of 1000 different fungi representing the full diversity of fungal families.  These data will serve as a foundation for an encyclopedic database that can be used worldwide to investigate fungal biochemistry and genetics. The culture collection of the Center for Forest Mycology Research (CFMR), in Madison, WI, will supply many of the fungal cultures used in this effort.  The CFMR collection includes many haploid cultures (those with a single copy of DNA) of the forest-inhabiting fungi needed in this project, greatly simplifying sequencing and interpretation of data.

Contact

Daniel Lindner, Research Plant Pathologist

Partners

National Science Foundation; USDA National Center for Genetic Resources Preservation and  Agricultural Research Service; Fungal Genetics Stock Center; University of California–Riverside; University of California--Berkeley; Vanderbilt University; University of Arizona; Cornell University; Centrallbureau voor Schimmelcultures, The Netherlands; Institut National de la Recherche Agronomique, France; Joint Genome Institute, California.


Nutritional and Defense Chemistry of Different Ash Species Influences Emerald Ash Borer Preference, Performance, and Feeding Behavior

Emerald ash borer adult feeding on an ash leaf. Photo by Deborah Miller, US Forest Service, NRS.

Emerald ash borer adult feeding on an ash leaf. Photo by Deborah Miller, US Forest Service, NRS.

The invasive emerald ash borer (EAB) was first discovered near Detroit, MI in 2002. It has since spread to 16 states and 2 Canadian provinces and killed an estimated 50 to 100 million ash trees, causing devastating economic and ecological impacts.  All eastern North American ash species are susceptible to EAB to some degree, including green, white, black, blue, and pumpkin ash, with green ash being highly preferred and susceptible.  Asian ash species in EAB’s native range appear to have some level of resistance. NRS scientist Therese Poland is working with colleagues to elucidate differences in nutritional and defense chemistry of different ash species and examine their roles in EAB preference and performance.  Understanding the mechanisms of host preference and resistance will be critical for incorporation into ash breeding programs to develop resistant trees. Research suggested that moisture content and nutrients were important selective forces in feeding behavior of EAB larvae.  Improved nutrient balance and increased efficiency of amino acid utilization in green ash may contribute to its preference by EAB.  Elevated levels of volatile compounds induced by adult foliar feeding in green and white ash, and lower levels of induced defensive compounds in green ash may also partially explain the preference for green ash by EAB. 

Contact

Therese Poland, Research Entomologist

Partners

Tina M. Ciaramitaro, Biological Sciences Technician, USDA Forest Service, NRS; Yigen Chen, Department of Entomology, Michigan State University (Current address: Department of Entomology, University of California, Davis, CA); Michael D. Ulyshen, Department of Entomology, Michigan State University (Current address:  USDA Forest Service, Southern Research Station, Starkville, MS); and Justin G.A. Whitehill and Peirluigi Bonello, Department of Plant Pathology, The Ohio State University.

More Information

Chen, Yigen; Ciaramitaro, Tina; Poland, Therese M. 2011. Moisture content and nutrition as selection forces for emerald ash borer larval feeding behaviour. Ecological Entomology. 36: 344-354.

Chen, Yigen; Poland, Therese M. 2010. Nutritional and defensive chemistry of three North American ash species: possible roles in host performance and preference by emerald ash borer. The Great Lakes Entomologist. 43 (1-4): 20-33.

Chen, Yigen; Ulyshen, Michael D.; Poland, Therese M. 2012. Differential utilization of ash phloem by emerald ash borer larvae: Ash species and larval stage effects. Agricultural and Forest Entomology. 14: 324-330.

Chen, Y.; Whitehill, J.G.A.; Bonello, P.; Poland, T.M.  2010.  Feeding by Emerald Ash Borer Larvae Induces Systemic Changes in Black Ash Foliar Chemistry.  Phytochemistry 72: 1990-1998.

Chen, Yigen; Whitehill, Justin G.A.; Bonello, Pierluigi; Poland, Therese M. 2011. Differential response in foliar chemistry of three ash species to emerald ash borer adult feeding. Journal of Chemical Ecology. 37: 29-39.


Evolutionary Studies of Carbon Sequestration Fungi

Beatriz Ortiz-Santana collecting fungi in the forests of Michigan.  Photo credit: Dana L. Richter, MTU-MI

Beatriz Ortiz-Santana collecting fungi in the forests of Michigan.  Photo credit: Dana L. Richter, MTU-MI

NRS scientists at the Center for Forest Mycology Research (CFMR) are conducting DNA-based studies on the largest evolutionary assemblage of brown rot fungi. Brown rot fungi are particularly important because they include many native forest pathogens and also degrade wood to create coarse woody debris, which many animals rely on as habitat. These fungi also play critical roles in carbon sequestration, improve the quality of forest soils, and influence forest structure and succession. Several members of the this group are indoor wood-decay and other species are considered good edibles or are important sources of pharmaceutical and biotechnological products. The scientists used molecular data to define species and to understand evolutionary relationships within this group. About 600 DNA sequences have been generated from 18 genera and 82 species of brown-rot fungi from United States, Europe and Asia. This contribution to the ''Fungal Tree of Life'' will greatly increase our understanding of the diversity and systematics of wood-inhabiting fungi, which in turn will facilitate research on the role of these fungi in forest ecosystems. An accurate identification of fungi in this group is essential for their development as a food source and for their pharmaceutical and biotechnological properties. An accurate assessment of the diversity of brown rot fungi in the forest will also help climate change scientists and forest managers in their estimates of the rates of carbon sequestration and development of soil organic matter from coarse woody debris.

Contact

Beatriz Ortiz-Santana, Botanist and Daniel Lindner, Research Plant Pathologist

Partners

David S. Hibbett and Alfredo Justo, Clark University; National Science Foundation (PolyPEET grant DEB 0933081)


U.S. National Culture Collection Network

CFMR Culture Collection Manager Rita Rentmeester preparing fungal cultures for long-term storage in liquid nitrogen. Photo Credit: Stephen A. Schmieding, Forest Products Laboratory

CFMR Culture Collection Manager Rita Rentmeester preparing fungal cultures for long-term storage in liquid nitrogen. Photo Credit: Stephen A. Schmieding, Forest Products Laboratory

The culture collection maintained by the Center of Forest Mycology Research (CFMR) in Madison, WI, has been included in a National Science Foundation-funded initiative to protect and support culture collections of plant-associated microorganisms. Collections of living microbes represent an essential foundation for U.S. science and the future bio-economy, but there is currently no system for preserving these collections or distributing information among collection managers. The U.S. National Culture Collection Network was established to develop a series of key resources needed by the collection community, including the development of shared informatics tools, networking among culture collection managers, the establishment of standard operating procedures for culture collection best practices, and the implementation of a loss-prevention plan to protect at-risk collections from destruction or degradation. This research collaboration network will also seek ways to institutionalize long-term support for culture collection scientists and users through the revitalization of the U.S. Federation of Culture Collections. Efforts will also be made to link U.S. culture collections with internationally based organizations. The RCN is funded by the National Science Foundation for 5 years for $500,000.  More information is available at http://www.usccn.org/Pages/default.aspx.

Contact

Jessie Glaeser, Research Plant Pathologist

Partners

National Science Foundation; USDA National Center for Genetic Resources Preservation; American Phytopathological Society; Fungal Genetics Stock Center; Pennsylvania State University; University of California–Davis; Oklahoma State University; Global Biological Resource Center Network


Elucidating the Biology of the European Oak Borer

Adult European oak borer

Adult European oak borer

The European oak borer (Agrilus sulcicollis) was discovered in North America in 2009- first in Ontario, Canada, and then in Michigan by NRS entomologists. The European oak borer is a close relative of the emerald ash borer (Agrilus planipennis), an Asian pest that has killed millions of ash trees in the United States since its discovery in 2002. In Europe, the European oak borer infests primarily oaks but occasionally it infests chestnut and beech. Almost nothing was known about the European oak borer in the United States in 2009, and over the past few years, Northern Research Station entomologist have studied its life cycle, host range, seasonal flight period, attraction to girdled trees and trap logs, attraction to traps of different colors, natural enemies, and morphological characters for distinguishing larvae of European oak borer from the native twolined chestnut borer (Agrilus bilineatus), the principal Agrilus pest on oak in eastern North America. Overall, the European oak borer appears to be much less aggressive than the emerald ash borer, suggesting that it will only be an occasional pest of oaks in the United States and probably always infesting oaks in association with the twolined chestnut borer. 

Contact

Robert A. Haack, Research Entomologist and Toby R. Petrice, Entomologist

Partners

Paul Bloese, Michigan State University

More Information

Haack, Robert A.; Petrice, Toby R.; Zablotny, James E. 2009. First report of the European oak borer, Agrilus sulcicollis (Coleoptera: Buprestidae), in the United States. Great Lakes Entomologist. 42: 1-7.


Control and Management

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:

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.


Unique Bacillus thuringiensis (Bt) Toxin-Binding Molecule Located in Gypsy Moth Gut

Fluorescent micrograph of gypsy moth BTR-270 localized in paraffin embedded midgut tissue section. BTR-270 (orange) was localized exclusively in the microvillar brush border of the midgut known to be the target site of Bacillus thuringiensis insecticidal proteins. Nuclei were stained blue with DAPI and the basement membrane was counterstained with a green fluorescent wheat germ agglutinin lectin. Photo by Al Valaitis, US Forest Service NRS.

Fluorescent micrograph of gypsy moth BTR-270 localized in paraffin embedded midgut tissue section. BTR-270 (orange) was localized exclusively in the microvillar brush border of the midgut known to be the target site of Bacillus thuringiensis insecticidal proteins. Nuclei were stained blue with DAPI and the basement membrane was counterstained with a green fluorescent wheat germ agglutinin lectin. Photo by Al Valaitis, US Forest Service NRS.

Ongoing research for over two decades has sought to understand how the insecticidal proteins produced by Bacillus thuringiensis (Bt) gain access to the brush border membrane of the gut cell, insert into the membranes, and promote cytotoxicity of intoxicated insect gut cells. A high affinity interaction with specific receptors located on the apical microvillar surface of gut cells in Bt-susceptible insects such as the gypsy moth is a crucial step in the mode of action of Bt. New studies by Northern Research Station scientists provide strong evidence that a unique proteoglycan-like molecule, BTR-270, serves as the receptor for the insecticidal Bt toxins in gypsy moth larvae. The topological location of BTR-270 in gypsy moth gut tissue was examined using specific antibodies in conjunction with fluorescence microscopy providing additional evidence that the receptor for toxin binding interactions is present exclusively along the electronegative surface of the midgut cells.


Emerald Ash Borer Natural Enemies Becoming Established in the United States

his tiny emerald ash borer egg parasitoid, Oobius agrili (Hymenoptera: Encyrtidae), is reproducing by laying its egg inside an emerald ash borer egg. In about a month, another O. agrili adult will emerge from this egg -- instead of an emerald ash borer larva.  Photo by Deborah Miller, US Forest Service NRS.

This tiny emerald ash borer egg parasitoid, Oobius agrili (Hymenoptera: Encyrtidae), is reproducing by laying its egg inside an emerald ash borer egg. In about a month, another O. agrili adult will emerge from this egg -- instead of an emerald ash borer larva. Photo by Deborah Miller, US Forest Service NRS.

Scientists with the Northern Research Station are working closely with other researchers, land managers, and citizen scientists to expand the USDA Interagency Emerald Ash Borer Biological Control Program. Biological control of EAB involves the release of small, highly specialized wasps, or ''parasitoids,'' that seek and destroy EAB eggs or larvae in ash trees. Since the first EAB parasitoids were released by Forest Service and Animal and Plant Health Inspection Service scientists in Michigan in 2007, the EAB Biological Control Program expanded EAB biological control to 15 states during 2012. During this time, NRS scientists and federal, state, and university collaborators have been working to develop non-destructive methods to determine parasitoid establishment in ash trees. This work is paying off, and parasitoid establishment is now confirmed at release sites in Michigan, Ohio, Indiana, Illinois, Maryland, and Pennsylvania. NRS scientists also began collecting data at field sites in Michigan to assess the long-term impact of EAB biological control on ash health and regeneration.

Contact

Leah S. Bauer, Research Entomologist

Partners

US Forest Service-  State & Private Forestry, Northeastern Area; Forest Health Technology Enterprise Team; Huron-Manistee and Hiawatha National Forests; USDA Agricultural Research Service; States of Michigan, Wisconsin, Missouri, Minnesota, Pennsylvania, New York; City of Chicago; Michigan State University; Wayne State University; Ohio State University; University of Masachusetts; Purdue University; University of Michigan; Michigan Tech University; SUNY-ESF; APHIS, Brighton, MI, Buzzards Bay, MA. 

More Information

Emerald ash borer - Biological Control - Natural enemies

Gould, Juli S.; Bauer, Leah S.; Lelito, Jonathan; Duan, Jian. 2012. Emerald ash borer biological control release and recovery guidelines. U.S. Department of Agriculture, Animal Plant Health Inspection Service, Forest Service Northern Research Station, and Agricultural Research Service. 76 p.

Duan, Jian J.; Bauer, Leah S.; Hansen, Jason A.; Abell, Kristopher J.; Van Driesche, Roy. 2012. An improved method for monitoring parasitism and establishment of Oobius agrili (Hymenoptera: Encyrtidae), an egg parasitoid introduced for biological control of the emerald ash borer (Coleoptera: Buprestidae) in North America. Biological Control. 60: 255-261

Duan, Jian J.; Bauer, Leah S.; Abell, Kristopher J.; van Driesch, Roy. 2012. Population responses of hymenopteran parasitoids to the emerald ash borer (Coleoptera: Bupresitidae) in recently invaded areas in north central United States. BioControl. 57: 919-209.

Liu, Houping; Bauer, Leah S.; Miller, Deborah L.; Zhao, Tonghai; Gao, Ruitong; Song, Liwen; Luan, Qingshu; Jin, Ruozhong; Gao, Changqi. 2007. Seasonal abundance of Agrilus planipennis (Coleoptera: Buprestidae) and its natural enemies Oobius agrili (Hymenoptera: Encyrtidae) and Tetrastichus planipennisi (Hymenoptera: Eulophidae) in China.  Biological Control 42: 61-71.

Zhang, Yanzhou; Huang, Dawei; Zhao, Tonghai; Liu, Houping; Bauer, Leah S. 2005. Two New Species of Egg Parasitoids (Hymenoptera:Encyrtidae) of Wood-Boring Beetle Pests from China. Phytoparasitica. 53(3): 253-260.


Comprehensive Program to Develop Emerald Ash Borer-Resistant Ash

Dissected tree showing an EAB early instar larva that has been killed by host tree defense responses.  Photo by: David Carey

Dissected tree showing an EAB early instar larva that has been killed by host tree defense responses.  Photo by: David Carey

The emerald ash borer has killed millions of ash trees in both urban and forested landscapes since it was first discovered near Detroit, MI, a decade ago. All eastern North American species of ash are known to be susceptible to EAB. Forest Service scientists are part of an interdisciplinary team that received a 3-year, $1.4 million grant from APHIS to develop EAB-resistant ash resources for the restoration of ash in both urban and natural landscapes. With expertise in ecology, genetics, plant propagation, and molecular biology, the team is working to identify EAB-resistance in both Asian and North American ash, understand the mechanisms of resistance, and breed ash trees with improved EAB-resistance. Researchers have identified candidate genes, proteins and chemicals involved in resistance by comparing an EAB-resistant Asian species to EAB-susceptible North American species. Once the role of these compounds in resistance is confirmed, work will begin to use them as biomarkers to screen for EAB-resistance in ongoing breeding programs, greatly accelerating the breeding and selection process. The research team is identifying additional EAB-resistant Asian ash species as well as rare native ash trees that have survived heavy EAB-infestations to use as parents in the breeding program.

Contact

Jennifer Koch, Research Biologist

Partners

Forest Service Research Partners/Collaborators:

Kathleen Knight and Therese Poland, US Forest Service Northern Research Station; Daniel A Herms and Omprakash Mittapalli, Department of Entomology, The Ohio State University, Ohio Agricultural Research and Development Center; Pierluigi Bonello, Department of Plant Pathology, The Ohio State University; Don Cipollini, Department of Biological Sciences, Wright State University

More Information

 

Whitehill, Justin G.A.; Popova-Butler, Alexandra; Green-Church, Kari B.; Koch, Jennifer L.; Herms, Daniel A.; Bonello, Pierluigi. 2011. Interspecific proteomic comparisons reveal ash phloem genes potentially involved in constitutive resistance to the emerald ash borer. PLoS ONE. 6(9): e24863. doi:10.1371/journal.pone.0024863

Rivera-Vega, Loren; Mamidala, Praveen; Koch, Jennifer L.; Mason, Mary E.; Mittapalli, Omprakash. 2012. Evaluation of reference genes for expression studies in ash (Fraxinus spp.). Plant Molecular Biology Reporter. 30: 242-245.


Silvicultural Thinning and Hemlock Vulnerability to Hemlock Woolly Adelgid

In order to reduce hemlock vulnerability in stands threatened by hemlock woolly adelgid (HWA), crowded stands have received silvicultural thinnings to increase hemlock crown size and health before HWA invasion.

In order to reduce hemlock vulnerability in stands threatened by hemlock woolly adelgid (HWA), crowded stands have received silvicultural thinnings to increase hemlock crown size and health before HWA invasion.

Due to periodic extreme winter temperatures, tree mortality in the northern range of hemlock can occur slowly and in patches for more than a decade. Long-term monitoring of tree health and growth rate is essential to document whether pre-invasion thinning practices are effective in reducing stand vulnerability after HWA arrival. In addition, prior research has suggested that HWA may have a preference for hemlock foliage with certain concentrations of nitrogen and other nutrients. Northern Research Station scientists looked at whether thinning treatments increased concentrations of foliar nutrients compared to stands that had not been thinned. Scientists sampled foliage in 3  study areas in Pennsylvania, annually, for 6 years and found that thinning treatments do not appear to have had an effect on any of the 10 foliar macronutrients that were tested. Although thinned stands did have higher soil N-mineralization rates, probably due to climatic and/or soil influences, foliar nitrogen trends were no different between treatments. These findings suggest that even though thinning treatments have increased growth rates and tree health, there was not difference in foliar nutrition compared to stands that had not been thinned.

Contact

Mary Ann Fajvan, Research Forester

Partners

 

Rick Turcotte, US Forest Service State & Private Forestry, Northeastern Area; Andrea Hille, Allegheny National Forest; West Virginia University; Pennsylvania State Game Commission; Massachusetts Department of Natural Resources; New Hampshire Division of Forest Lands

More Information

Fajvan, Mary Ann. 2008. The role of silvicultural thinning in eastern forests threatened by hemlock woolly adelgid (Adelges tsugae). In: Deal, R.L., tech. ed. Integrated restoration of forested ecosystems to achieve multiresource benefits: proceedings of the 2007 national silviculture workshop; 2007 May 7-10; Ketchikan, AK. Gen. Tech. Rep. PNW-733. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station: 247-256.


Hybridization between a predator introduced for biological control of hemlock woolly adelgid and a native species

Laricobius rubidus, a native Eastern beetle species that is hybridizing with   a Western species introduced as a biological control of hemlock woolly adelgid. Photo  by Nathan Havill, US Forest Service NRS.

Laricobius rubidus, a native Eastern beetle species that is hybridizing with a Western species introduced as a biological control of hemlock woolly adelgid. Photo by Nathan Havill, US Forest Service NRS.

Hybridization between introduced biological control agents and native species has the potential to impact native biodiversity and pest control efforts. Laricobius nigrinus is a predaceous beetle from western North America that was introduced to the eastern U.S. for biological control of the hemlock woolly adelgid. More than 200,000 beetles have been released in 17 states. In the East, there is a closely related native species, Laricobius rubidus, which also feeds on hemlock woolly adelgid but prefers pine adelgids. Nuclear and mitochondrial DNA was used to examine whether the two species are hybridizing in release sites in the east. We found widespread hybridization across the landscape. This is the first example of widespread hybridization between a biological control agent and a native species. It is not yet known what the ultimate outcome of hybridization between these species will be, but it appears that there is little preventing the species from finding each other and producing viable offspring. This study confirms the importance of evaluating the potential for introduced biological control agents to hybridize with their native relatives. The results will influence the way we choose species to release for biological control in the future.

Contact

Nathan P. Havill, Research Entomologist

Partners

Scott Salom, Gina Davis, Melissa Fischer - Department of Entomology, Virginia Tech; Adalgisa Caccone, Joanne Klein - Department of Ecology and Evolutionary Biology, Yale University; David L. Mausel - Forestry Department, Menominee Tribal Enterprises; Symbiont Biological Pest Management; and Cera Jones - North Georgia College and State University

More Information

 

Klein, J.; Havill, N.; Caccone, A. 2010. Polymorphic microsatellite loci for Laricobius nigrinus and L. rubidus (Coleoptera: Derodontidae), predators of the hemlock woolly adelgid. Molecular Ecology Resources 10: 752-754.

Davis, G; Havill, N.; Adelman, Z.; Caccone, A.; Kok, L.; Salom, S. 2011. DNA barcodes and molecular diagnostics to distinguish between an introduced and native Laricobius (Coleoptera: Derodontidae) species in eastern North America. Biological Control 59: 53-59.

Havill, N.;, Salom, S.; Davis, G.; Fischer; M.; Mausel, D.; Onken, B. 2011. The introduction of Laricobius nigrinus as a biological control agent for the hemlock woolly adelgid:  Is there a threat to the native congener, L. rubidus? In: Implementation and Status of Biological Control of the Hemlock Woolly Adelgid. B. Onken and R. Reardon, eds.

Havill NP, Davis G, Mausel D, Klein J, McDonald R, Jones C, Fischer M, Salom S, Caccone A. In press. Hybridization between a native and introduced predator of Adelgidae: An unpredicted result of classical biological control. Biological Control.



Can We Prevent Nonnative Plant Species from Interfering With Oak Regeneration?

Japanese stiltgrass on a study plot.

Japanese stiltgrass on a study plot.

Oak regeneration in eastern U.S. forests is associated with fire and harvesting.  Forest canopy openings of any kind lead to invasions by non-native invasive plant species, creating a dilemma for forest managers.  Invasive plant establishment is also dependent on available resources as defined by site topography and regional gradients.  Northern Research Station scientists compared survival and productivity of three invasive plants – garlic mustard, Japanese stiltgrass, and tree of heaven – at 56 sites in the Allegheny Plateau and Ridge and Valley Provinces, across northeastern and southwestern slopes. Five management regimes in these regions and local gradients were evaluated:  control, single burn, repeat burn, shelterwood, and diameter-limit cutting. Garlic mustard had greater survival in the Allegheny Plateau and in both burn types, but Japanese stiltgrass and tree of heaven showed no difference in survival.  All three species had more biomass in the shelterwoods.  Japanese stiltgrass and tree of heaven’s productivity was greater in the Ridge and Valley and garlic mustard’s productivity was greater on northeastern slopes.  No difference in survival suggests that some invasive plants can become established, but not prosper, in undisturbed forests as well as disturbed forests.  Garlic mustard may be more sensitive to existing environmental and disturbance conditions.

Contact

Cynthia D. Huebner, Research Botanist

Partners

These results are part of a larger four-year project funded by the National Research Initiative, CSREES (now NIFA) involving US Forest Service Northern ResearchStation scientists (including Cynthia D. Huebner, Matt Dickinson, Rakesh Minocha, Gary Miller, and Chris LeDoux).  Other FS cooperators include the Monongahela National Forest, the Wayne National Forest, and the George-Washington-Jefferson National Forest; Glenn Matlack and two Masters students (Ohio University); David McGill and one Masters student (West Virginia University); Zaleski State Forest of Ohio; Plum Creek Timber Industries; Beckwith Timber; NewPage; Pardee –Curtin Timber; Ms. Jeanie Riggleman;, Mr. Douglas Grimes; and Mr. Scott Funkhouser.  There are 56 plots located across Ohio, West Virginia and Virginia on public and private lands, requiring coordination with public and private landowners as well as several timber industries.


Molecular Techniques Speed Biodiversity Studies in Threatened Eastern Hemlock Stands

Image is provided as an example image, it would be possible to produce a similar image made up of many (up to several hundred) different arthropods

Image is provided as an example image, it would be possible to produce a similar image made up of many (up to several hundred) different arthropods

The stability and sustainability of Eastern and Carolina hemlock are threatened in the eastern United States by an invasive insect, the hemlock woolly adelgid (HWA).  In addition to posing a threat to the trees themselves, the adelgids pose a risk to hundreds to thousands of species associated with hemlock.  Evaluating these threats by surveying the ecological communities is both labor intensive and time consuming. Continued reductions in the cost and speed of molecular “barcoding” (the use of the mitochondrial CO1 gene) and the development of the Barcode of Life Database (BOLD) have provided an opportunity to rapidly and accurately evaluate the rich community of arthropods in forests impacted by HWA.  Currently, the CO1 gene is being used to identify the approximately 1000 spider and insect species found associated with the Eastern hemlock, and to evaluate the potential for multiple management options (including the use of insecticides and the development of hybrid hemlocks) to buffer these forest systems against losses of biodiversity.

Contact

Talbot Trotter, Research Ecologist and Nathan P. Havill, Research Entomologist

Partners

Gisella Caccone, Yale University; Mark Ashton, Yale School of Forestry and Environmental Studies; Evan Preisser, University of Rhode Island; Richard Cowles, Connecticut Agricultural Experiment Station

More Information

Ingwell, L.; Miller-Pierce, M.; Trotter, R. T.; . Preisser, E. in press. Vegetation and invertebrate community response to Eastern hemlock decline in southern New England.  Northeastern Naturalist.


Nun Moth Natural Enemies

Collaborator injecting Nun moth larva with Entomophaga miamiaga. Photo by Melody Keena, US Forest Service NRS.

Collaborator injecting Nun moth larva with Entomophaga miamiaga. Photo by Melody Keena, US Forest Service NRS.

Proactive research on the nun moth is aimed at preventing the introduction and establishment of this potentially devastating Eurasian pest of conifers that is closely related to the gypsy moth to North America. Nun moth is the first nonnative insect species not established in North America that the Forest Service has received permission from APHIS for continuous rearing in the Forest Service’s Quarantine Facility. This nun moth research is expected to become a model for future proactive research to prevent the introduction and establishment of high-risk exotic pest species. Preventing such an infestation could save enormous amounts of time, money, and ecological destruction. Recent activities on the nun moth include 1) full review of all its known natural enemies and determination that some established gypsy moth parasitoids will also kill nun moth; 2) documentation of susceptibility to Entomophaga maimaiga; 3) development of DNA methods to distinguish these moths; and 4) development of methods to bioassay control options or rear natural enemies for this insect.

Contact

Melody Keena, Research Entomologist

Partners

Ann Hajek, Cornell University; Jeremy R. deWaard, Forest Sciences, University of British Columbia, Vancouver Canada; Leland M. Humble, Canadian Forest Service, Natural Resources Canada, Victoria, British Columbia; and Oldřich Pultar, Forest and Game Management Research Institute, Forestry Protection Department, Znojmo, Czech Republic

More Information

Keena MA, Vandel A, and Pultar O. 2010. Phenology of Lymantria monacha (Lepidoptera: Lymantriidae) laboratory reared on spruce foliage or a newly developed artificial diet. Annals Ent. Soc. 103(6):949-955.

deWaard, Jeremy R.; Mitchell, Andrew; Keena, Melody A.; Gopurenko, David; Boykin, Laura M.; Armstrong, Karen F.; Pogue, Michael G.; Lima, Joao; Floyd, Robin; Hanner, Robert H.; Humble, Leland M. 2010. Towards a global barcode library for Lymantria (Lepidoptera: Lymantriinae) tussock moths of biosecurity concern. PLoS ONE. 5(12): e4280. 10 p.


Effects and Impacts

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:

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:

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


Changing Climate, Changing Forests

Cover image from Changing Climate, Changing Forests: The Impacts of Climate Change on Forests of the Northeastern United States and Eastern Canada

Cover image from Changing Climate, Changing Forests: The Impacts of Climate Change on Forests of the Northeastern United States and Eastern Canada

Northern Research Station scientists and a large nationwide team analyzed the extensive literature on the potential effects of climate change on northeastern forest ecosystems and provided a concise scientific overview to inform natural resource management and policy decisions. They found that the evidence is now irrefutable that the climate of the northeastern United States and eastern Canada has changed in the last century and greater change is projected in the future. These changes have had and will continue to have dramatic impacts on northeastern forests. Projections include shifts in suitable habitat for forest tree species, with significant declines in suitable habitat for spruce-fir forests and expansion in area of suitable for oak-dominated forests; changes in forest productivity, with possible gains from extended growing seasons and CO2 and nitrogen fertilization and offsetting losses associated with atmospheric deposition of pollutants, forest fragmentation, and forests pests and pathogens; changes in the distribution and abundance of wildlife species through changes in habitat, food availability, thermal tolerances, and susceptibility to parasites and disease; alterations in forest water and nutrient cycling, and expansions in the range and virulence of pests, pathogens and invasive species. With the accumulating evidence of climate change and its potential effects, forest stewardship efforts would benefit from integrating climate mitigation and adaptation options in conservation and management plans.

Contact

Lindsey Rustad, Research Ecologist

Partners

John Campbell, Louis R. Iverson, S.N. Matthews, Jennifer Pontius, A. Prasad, US Forest Service Northern Research Station; Jeffrey S. Dukes, Purdue University; Thomas Huntington, U.S. Geological Survey; Kathy Fallon Lambert, Harvard Forest; Jacqueline Mohan, University of Georgia, Odum School of Ecology; Nicholas Rodenhouse, Wellesley College; plus about 40 additional contributors and co-authors

More Information

Rustad, L.E.; Campbell, J.L.; Dukes, J.S.; and others. 2012.  Changing Climate, Changing Forests:  The  Impacts of Climate Change on Forests of the Northeastern United States and Eastern Canada.  GTR-NRS-99. Newtown Square, PA:  USDA Forest Service, Northern Research Station.



Restoration of floodplains impacted by emerald ash borer

Restoration of flood plains impacted by emerald ash borer, Newly planted elm seedlings beside an ash tree.

Restoration of flood plains impacted by emerald ash borer, Newly planted elm seedlings beside an ash tree.

As emerald ash borer (EAB) spreads and impacts forest ecosystems, managers need methods to restore ash floodplain forests. To evaluate the best timing for replanting forests devastated by EAB, Northern Research Station scientists planted tree seedlings in three scenarios: forests where the ash trees had already been killed by EAB, forests where the trees were currently being killed by EAB, and forests where the trees had not yet been killed. The tree species planted in the project were pin oak, sycamore, and an elm that is tolerant to Dutch elm disease (DED) bred by Jim Slavicek (NRS) as crosses between DED-tolerant cultivars. Elm used to be a dominant tree species in these ecosystems before DED killed almost all of the large trees, and it is exciting to be returning it to these forests. Tree plantings were done in collaboration with the Columbus Metroparks, Summit County Metroparks, and as part of an ARRA project with the Toledo Metroparks. Survival of the planted trees has been good, especially considering the torrential flooding of 2011 and the drought of 2012, demonstrating that all three species are well-adapted to floodplain conditions. The restoration plantings benefit to the parks by filling in gaps left the loss of ash trees and increasing the diversity of the forest canopy .

Contact

Kathleen Knight, Research Ecologist

Partners

Jim Slavicek, US Forest Service Northern Research Station; Columbus Metro Parks; Metroparks Serving Summit County; Metroparks of the Toledo Area; John Cardina (The Ohio State University)

 

More Information

Knight KS, Slavicek JM, Menard K, Pisarczyk E, Wiggin B, and Kappler R. In press. Using Dutch elm disease-tolerant elm to restore floodplains impacted by emerald ash borer. In: Sniezko RA, Yanchuk AD,  Kliejunas JT, Palmieri KM, Alexander JM, and Frankel S.J. Tech. Coords. Proceedings of the 4th International Workshop on the Genetics of Host-Parasite Interactions in Forestry: Disease and Insect Resistance in Forest Trees. July 31 – August 5 2011, Euguene, OR.


Last Modified: October 2, 2015