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Northern Research Station
One Gifford Pinchot Drive
Madison, WI 53726
(608) 231-9200
(608) 231-9544 TTY/TDD

Sustaining Forests

Conserve and Enhance Wildlife and Fish

Animals inhabiting our forests, including the waters flowing over it and the air above it, are important to a large segments of society. Some come to view the animals and birds, others to hunt or fish. Some are content just to know that these creatures exist in the wild in viable numbers. Several Federal laws such as the National Forest Management Act and Endangered Species Act mandate viable wildlife populations. Recent research has demonstrated the importance of factors at multiple spatial scales on the viability of wildlife populations. For example, the vegetative composition and structure of a forest stand affects the abundance of birds breeding there, but the reproductive success of individuals may be affected by factors ranging from a nest site microhabitat to a landscape or region. Our scientists have also studied the ability of hardwood forests to regenerate when white-tailed deer populations are excessive. The NRS has one unit dedicated to wildlife and fish research and scientists in several other units who study wildlife as part of their forest ecosystem management research.

Northeastern and Midwestern forests are home to a wide variety of animal species. Some of these have exacting requirements for maintaining sustainable populations (Kirtland’s warbler for example); other species are quite adaptable and can live in many environments, even urban forests (think racoons and coyotes). Because much of the forested lands in the NRS region are privately owned and managed, NRS scientists focus much of their research on wildlife living in managed forests. Species studied include early-succession shrubland birds in old fields and powerline rights-of-way, neotropical migrants and songbirds; as well as terrestrial salamanders, fish, bats, and butterflies.

Research Studies

The blackburnian warbler is one of several species that were more abundant in Norway spruce plantations than any of the native forest types we sampled in central Massachusetts. Photo by Bill Thompson, US National Park Service.Non-native Norway Spruce May Become Essential Bird Habitat
In western Massachusetts, non-native Norway spruce (Picea abies) were planted in the early 1900s as a potential commercial species, but now land managers are wondering whether they should retain them to support native wildlife. Native eastern hemlocks (Tsuga canadensis) are in decline from an invasive Asian beetle known as the hemlock wooly adelgid. Norway spruce share characteristics with eastern hemlocks, such as short needles and dense canopy cover, and could possibly serve as surrogate habitat for native wildlife.


Fencing around study area to keep deer out.Hunting for Trees’ Sake Researching Hunting’s Effects on Deer Browsing
Northern Research Station researchers and Menominee Tribal Enterprises staff are collaborating on a 10-year study to test the impact of deer browsing on tribal lands. Researchers will monitor seedling growth within fenced and non-fenced areas both on and off tribal land. Researchers will note seedling survival rates, growth, species diversification, and overall forest densities within the research area.


Adult Acadian flycatcher on nest.Threat of Climate Change to Songbird Breeding Population
Much of the research taking place on the effects of climate change on wildlife is focused on habitat, and frequently on habitat used by species that are already imperiled. If wildlife managers are going to successfully navigate the conservation challenges they face today and into the next century, they will need to understand the mechanisms by which climate affects breeding, interspecies interactions, and other demographic processes for common and imperiled birds.


Female wood turtle. Photo by Joel Flory, SUNY-ESF. Used with permission.Movement Patterns of Wood Turtles Using Genetic Approaches
Conservation efforts for disconnected populations can be improved with information on broad-scale dispersal movement patterns. Using landscape genetic approaches can identify movement patterns by characterizing population structure and linking this structure spatially with landscape features. Wood Turtles (Glyptemys insculpta) are a species of concern due to reported range-wide population declines. The western Great Lakes population is disconnected from the larger northeastern population.  The western population is found primarily in northern Wisconsin and Minnesota, and consists of small, isolated population distributed patchily across the landscape. An isolated population exists in Iowa. Previous genetic research in this region showed evidence of lower allelic richness and heterozygosity indicating spatial isolation, but sampling was limited. The loss of genetic diversity has major implications on species persistence, and identifying potential landscape barriers to movement, and thus, gene flow, is imperative.  


[photo:] Young male Kirtland’s warbler.  Photo by Kyle Sommers, US Forest Service Hiawatha National Forest intern.Managing Species of Conservation Concern: Kirtland’s Warbler under Changing Environmental and Management Conditions
The Kirtland’s Warbler (Setophaga kirtlandii) is an endangered migratory songbird that breeds primarily in Michigan and winters in the Bahamian Archipelago. The species is an extreme habitat specialist on the breeding grounds, showing a strong preference for large, dense patches of young jack pine (Pinus banksiana) and well-drained sandy soils. Due to intensive collaborative management, the species has recovered from ca. 200 breeding males in 1971 to ca. 2,000 breeding males today. With the potential for delisting, continued conservation and management requires more information on how changing environmental conditions in both the breeding and wintering groundscould impact the long-term viability of the species.


[photo:] Species viability graph.Mature-forest birds benefit by shifting to early-successional habitat after breeding
Populations of many migratory birds that require large tracts of mature forest to nest are declining across the eastern states, despite the fact that our forests are maturing and in many states are stable or increasing in area. Birds provide vital ecological functions in forests, including pest control and seed dispersal, so continued declines in bird populations may negatively affect forest health and regeneration.  


[photo:] Species viability graph.Population and Genetic Modeling Methods for Assessing Species Viability and Evaluating Conservation Strategies
The ability of populations to sustain themselves in the face of global change, habitat fragmentation and loss, invasive species, and other threats depends on population processes that occur over large scales.  As a result, conservation efforts increasingly target larger spatial scales.  Landscape-based demographic models have rarely been applied at ecoregional scales.  


[photo:] golden cheeked warbler.  Photo from US FWS.Habitat and Resource Selection by Wildlife Species of Conservation Concern
Knowledge of wildlife species habitat or resource needs is a basic requirement for wildlife management.  The Indiana bat (Myotis sodalis) has been on the United States Endangered Species List since 1967.  Knowledge of how landscape and forest management affect forest wildlife, like the Indiana bat, will allow resource managers to make more informed management decisions that will aid in the recovery of species.  


[photo:] A managed savanna site in the Missouri OzarksEffects of savanna and woodland restoration on bats and birds in the central hardwood region
There is great interest in restoring savanna and woodlands because of their former abundance on the landscape and high floristic diversity.  However, there is not good knowledge of the effects of restoration on wildlife or of potential conflicts with management for forest species of conservation concern.  


[photo:] Landscape Diversity, Vegetation types, National Wildlife Federation, GLA websiteConserving Wildlife in Managed Forests
Public land managers are mandated to sustain viable populations of all species on their lands, which requires an understanding how wildlife populations respond to forest management practices. Our research focuses on forest birds, as populations of many species of eastern deciduous forests are declining across their range, raising concerns over possible negative effects of timber management.  


[photo:] Landscape Diversity, Vegetation types, National Wildlife Federation, GLA websiteEffects of forest composition on Northern Goshawk nest occurrence and productivity
The Northern Goshawk is a forest raptor found at low densities throughout northern hardwood forests of the Great Lakes region, and is a species of management concern for the Chequamegon-Nicolet National Forest (CNNF), Wisconsin.  The species has a circumboreal distribution and appears to be quite flexible in its nesting requirements and prey base, which limits the applicability of literature on nesting and foraging requirements from outside of the Great Lakes region.  Therefore, there is a need for local information on these aspects of Northern Goshawk biology to inform land managers of the most effective means to conserve the species. 


Crop Tree Management
Crop tree management (CTM) is a widely applicable silvicultural technique used to enhance the performance of individual trees. It offers flexibility in that it can be applied on small or large properties and, with certain modifications, it can be applied as a precommercial or commercial operation. 


Thinning treatments
To apply effective thinning treatments, land managers need answers to several important questions: How do individual trees respond to reduced crowding?  How does thinning affect wood quality and tree vigor?  How does thinning affect wildlife habitat? Do harvest operations associated with thinning damage the residual forest? What are the financial impacts associated with thinning?


[photo:] Intensively managed pecan sapling with weed control, deer protection, and pruning to maintain central stem.Intensive Management of Hardwood Plantings
In the 1960s the diminishing supply of quality hardwood saw timber, especially black walnut, raised the question of how best to grow hardwoods in plantations to assure future supplies.  At the time, we determined the most promising native hardwood for timber production in intensively managed plantings was black walnut, white ash, and several of the oak species.  


[photo:] Swamp white oak 8 years after being planted as a large container seedlings grown by the Root Production Method (RPM®) in a former agricultural crop field along the Missouri River.  Trees were planted with redtop grass to control competition.Restoring Forests in Bottomland Fields
We have identified several promising practices and seedling types that can be used to successfully restore oak to future bottomland forests when bringing marginal agricultural lands back into forest production.


[photo:]  Red maple stem heating experiment.Fire Effects in Eastern Forests
Understanding fire effects requires consideration of the processes by which the effects occur.  We are applying process-based (mechanistic) approaches to modeling fire effects on endangered Indiana bats and fire-caused tree injury and mortality.  Fires pose risks for bats but also provide opportunities for improving bat roosting habitat, our project considers both sides of the problem. 


[photo:] Moderate-intensity surface fire in mixed-oak forestEcosystem Management Study: Restoration of Mixed-oak Forests with Prescribed Fire
Historically, fire was a frequent disturbance process in the mixed-oak forests of the central hardwoods region. Fire control has altered forest structure and composition. Forests are more dense and the sustainability of oak and hickory dominance is now threatened by an abundance of shade-tolerant and fire sensitive tree species such as red maple, sugar maple, and beech. Prescribed fire has been advocated to promote and sustain open-structured mixed-oak forests and the plants and animals that have adapted to these communities. However, long-term research on fire effects is lacking.


[photo:] Redring milkweed (Asclepias variegata), growing in an Ohio mixed-oak forest after repeated prescribed fires.Plant Diversity in Managed Forests
The great majority of plant diversity in forests is contained in the herbaceous layer, comprised of both herbaceous and woody species.  We seek a better understanding of how forest management activities affect plant diversity.  NRS-2 scientists are investigating the direct and indirect effects of timber harvesting, prescribed burning, herbicide application, and deer browsing (alone and in combination) on plant composition and diversity in mixed oak, Allegheny, and Northern Hardwood forests.


[image:]  Map of contigous USA - shows locations of FFS sitesFire and Fire Surrogate Treatments: The Central Appalachian Plateau Site
Current forests in many fire-dependent ecosystems of the United States are denser and more spatially uniform, have many more small trees and fewer large trees than did their presettlement counterparts. Causes include fire suppression, past livestock grazing and timber harvests, and changes in land use. The results include a general deterioration in forest ecosystem integrity and the threat of losing important, widespread forest types. Such conditions are prevalent nationally, especially in forests with historically short-interval, low- to moderate-severity fire regimes, such as the upland oak forests of the central hardwoods region.   


[photo:]  Sugar Maple Decline on the unglaciated Allegheny Plateau in northern PennsylvaniaSite, Stress, Nutrition, and Forest Health Interactions
A range of stressors including defoliating insects, pathogens, droughts, inadequate soil base cations, and changing climate have interacted to affect the health and regeneration of selected northern and central hardwood forest species. In the 1980s and 1990s sugar maple dieback and mortality was extensive across the unglaciated Allegheny Plateau in northern Pennsylvania. 


Photo: Atlantic SalmonStream habitat for Atlantic salmon fry and parr
The NRS roster of scientists even includes a fisheries biologist! His research focuses on the effects of change in habitat, land use, hydrology, and food-web structure on Atlantic salmon and trout in New England stream ecosystems. Large woody debris (LWD, that is, fallen logs and branches) are an important component of good aquatic habitat for trout and salmon, as they control the flow speed and thus sediment load, create pools, and provide nutrients for invertebrates. Our scientists works with New England and international groups that are working to preserve wild runs of salmon in the east and to reintroduce the Atlantic salmon into its historical habitat on both sides of the Atlantic Ocean.


Last Modified: 01/05/2021