Science of the Seasons

Winter 2019

Aside from bitter cold ushered in by the occasional polar vortex, data shows that winter in the Northeast and Midwest is becoming warmer and wetter than in the past. Increased climate variability means winter storms are becoming more extreme and winter weather is yielding to spring temperatures earlier in the year. These shifts have the potential to change the range of invasive insects such as the hemlock woolly adelgid and habitat suitability for native tree species.

This page brings together Northern Research Station science that relates to the winter season, along with links to other seasonal resources within the USDA Forest Service.

Scientists Perspectives on the Seasons

Ice covered trees from scientifically simulated ice storm experiment on Hubbard Brook Experimental Forest.Winter. Just the word evokes the feeling of snow on your face, bone-chilling wind, and hard frozen ground. Changing climate conditions may redefine winter, however, and that has ramifications for everything from invasive insects to the farm economy. From the Mid-Atlantic to the Northwoods and from the Central Appalachians to the Central Hardwoods Region, observed trends in climate over the historical record show that the mean annual temperature has increased, with even greater warming during winter. What difference can a couple of degrees make? Projected changes in climate precipitation will have important implications for economically valuable timber species, forest-dependent animals and plants, recreation, and long-term natural resource planning

Forest vulnerability assessments for forest ecosystems in the Northeast and Midwest are available at:

[photo:] Hemlock woolly adelgid on an eastern hemlock twig.
For more than half a century, the tiny, aphid-like hemlock wooly adelgid (HWA) has been creeping out of urban forests and into rural forests, resulting in the widespread decline and death of hemlock trees in the eastern United States.

Three beetle species may serve as a desperately needed defense for hemlock trees embattled by the HWA. A leading question for Northern Research Station scientists is whether the beetle species Scynmnus sinuanodulus, Sasajiscymnus tsugae, and Laricobius nigrinus can survive winter, which is an active season for the adelgid.  

Northern Research Station scientists are using electronic “bug condos” to examine the impact of temperature on feeding behavior, to identify the conditions under which feeding will take place, and those conditions, such as post-feeding freeze that may place the beetles at risk. 

Learn more at:

Selected Research Stories

Selected Publications

The publications listed below do not represent every study related to winter; for a more complete list of NRS publications, please visit our Publications page at:

Christianson, Lindsey; Venette, Robert. 2018. Modest Effects of Host on the Cold Hardiness of Emerald Ash Borer. Forests. 9(6): 346-.

Janowiak, Maria K.; D'Amato, Anthony W.; Swanston, Christopher W.; Iverson, Louis; Thompson, Frank R., III; Dijak, William D.; Matthews, Stephen; Peters, Matthew P.; Prasad, Anantha; Fraser, Jacob S.; Brandt, Leslie A.; Butler-Leopold, Patricia; Handler, Stephen D.; Shannon, P. Danielle; Burbank, Diane; Campbell, John; Cogbill, Charles; Duveneck, Matthew J.; Emery, Marla R.; Fisichelli, Nicholas; Foster, Jane; Hushaw, Jennifer; Kenefic, Laura; Mahaffey, Amanda; Morelli, Toni Lyn; Reo, Nicholas J.; Schaberg, Paul G.; Simmons, K. Rogers; Weiskittel, Aaron; Wilmot, Sandy; Hollinger, David; Lane, Erin; Rustad, Lindsey; Templer, Pamela H. 2018. New England and northern New York forest ecosystem vulnerability assessment and synthesis: a report from the New England Climate Change Response Framework project. Gen. Tech. Rep. NRS-173. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 234 p.

Snyder, Keirith A.; Evers, Louisa; Chambers, Jeanne C.; Dunham, Jason; Bradford, John B.; Loik, Michael E. 2018. Effects of changing climate on the hydrological cycle in cold desert ecosystems of the Great Basin and Columbia Plateau. Rangeland Ecology and Management.

Tussey, Dylan A; Aukema, Brian H; Charvoz, Anthony M; Venette, Robert C. 2018. Effects of Adult Feeding and Overwintering Conditions on Energy Reserves and Flight Performance of Emerald Ash Borer (Coleoptera: Buprestidae). Environmental Entomology. 47(3): 755-763.

Wolcott, Daniel M.; Donner, Deahn M.; Brown, Donald J.; Ribic, Christine A. 2018. Kirtland's warbler winter habitat changes across the Bahamian Archipelago in response to future climate-condition scenarios. Caribbean Naturalist. 49: 1-20.

Wolfe, David W.; DeGaetano, Arthur T.; Peck, Gregory M.; Carey, Mary; Ziska, Lewis H.; Lea-Cox, John; Kemanian, Armen R.; Hoffmann, Michael P.; Hollinger, David Y. 2018. Unique challenges and opportunities for northeastern US crop production in a changing climate. Climatic Change. 146(1-2): 231-245.

Schaberg, Paul; Murakami, Paula; Hawley, Gary J.; Collins, Kendra. 2017. American chestnut restoration in New England - cold damage as an added challenge. New England Society of American Foresters News Quarterly. 78(3): 8-11.

Strimbeck, G. Richard; Schaberg, Paul G.; Fossdal, Carl G.; Schroder, Wolfgang P.; Kjellsen, Trygve D. 2015. Extreme low temperature tolerance in woody plants. Frontiers in Plant Science. 6. doi: 10.3389/fpls.2015.00884 (15 p.).

Stay Connected

Blog icon   Facebook icon  RSS icon  Twitter icon  YouTube icon

Environmental Education

Four climbers cross a stretch of snowy mountain
Winter hiking and climbing take special preparation and planning. Here are some resources to help put you on the right path.

❄️ Winter Hiking Safety Tips ~ U.S. Forest Service
❄️ Know Before You Go - Hiking

Featured Podcasts

Hemlock Woolly Adelgid

Kelly van Frankenhuyzen talks with U.S. Forest Service experts about hemlock woolly adelgid and it's impacts on eastern hemlock forests.

  • Andrea Hille, Silviculturist, Allegheny National Forest, Pennsylvania
  • Nathan Havill, Research Entomologist, Northern Research Station, Hamden, Connecticut
  • Therese Poland, Research Entomologist and Project Leader of Ecology and Management of Invasive Species in Forest Ecosystems research work unit, Lansing, Michigan

Royalty free music from

Right click to download MP3 file (9 mb)

Download transcript


Ice Storm Experiment

Kelly van Frankenhuyzen talks with U.S. Forest Service experts about the Hubbard Brook Ice Storm Experiment and the importance of studying ice storms.

Royalty free music from

Right click to download MP3 file (8 mb)

Download transcript


View our podcast archive

Last Modified: February 5, 2019