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- Ryan O'Connor
Natural Heritage Inventory Ecologist
608-266-7714
Oak Woodland
Photo by Drew Feldkirchner
- WDNR
State Rank: S1? Global Rank: GNR what are these ranks?
Definition
Detailed Community Description from Ecological Landscapes of Wisconsin
General natural community overview
The oak woodland community occupies a position on the vegetation continuum that is intermediate between the oak savannas (especially Oak Openings) and the oak forests (especially Southern Dry Forest). Oak woodland differs from oak savanna types in that they lack the wide-spreading crowns and thick boles associated with savannas, and they have greater crown closure, with an approximate range of 50% to as much as 95%. As presently understood, the latter attribute is not simply the result of the canopy closure that affected most savannas following the implementation of wildfire suppression policies earlier in the twentieth century. As soon as fire suppression policies were widely implemented in southern Wisconsin, the rapid proliferation of shrubs and saplings would have quickly altered stand structure, causing the open understories of the Oak Woodland communities to disappear. Describing the differences between woodland and forest is difficult because of the absence of intact reference stands, but the Oak Woodland was subjected to frequent (annual) wildfires of low intensity, lacked the dense woody understory that characterizes most dry oak forests, and often had relatively lower canopy closure than true forest.
Dominant trees included white oak (Quercus alba), bur oak (Quercus macrocarpa), and black oak (Quercus velutina), sometimes mixed with red oak (Quercus rubra) and shagbark hickory (Carya ovata). Under a characteristic fire regime, shrub and sapling representation in oak woodlands would be minimal. The herb layer is potentially diverse, including some members of the prairie, oak savanna, and oak forest communities, but also featuring grasses, legumes, composites and other forbs that are best adapted to light conditions of highly filtered shade. Representative herbs may include upland boneset (Eupatorium sessilifolium), violet bush-clover (Lespedeza violacea), Virginia bush-clover (Lespedeza virginica), Culver's-root (Veronicastrum virginicum), rough-leaved sunflower (Helianthus strumosus), eastern shooting-star (Primula meadia), Short's aster (Symphyotrichum shortii), yellow-pimpernel (Smyrnium integerrimum), bottlebrush grass (Elymus hystrix), silky wild-rye (Elymus villosus), and bracted tick-trefoil (Desmodium cuspidatum).
Many of the same plants and animals that reach their optimal abundance in the oak openings also occur in oak woodland, including red-headed woodpecker, orchard oriole, eastern bluebird, and kitten-tails. Oak woodland can also support forest species, such as yellow-throated vireo, scarlet tanager, tufted titmouse, and blue-gray gnatcatcher, and in large stands, some species that are restricted to forest interior conditions, such as the cerulean warbler.
The geographic range historically occupied by oak woodland would be virtually the same as that of oak openings and prairies in southern Wisconsin. Oak woodland would have been most common on sites that experienced frequent, low-intensity ground fires. Moisture conditions would have included dry, dry-mesic, mesic, and, possibly, wet-mesic sites. Today oak woodland is most likely to occur in those parts of southern Wisconsin that continue to support relatively large areas of natural vegetation that include prairie and savanna remnants in proximity to oak-dominated forests. Portions of the Driftless Area, the kettle interlobate moraine of southeastern Wisconsin, and perhaps portions of the Central Sand Hills, offer the best potential. This type is extraordinarily rare today.
Rare animals
Species of Greatest Conservation Need
The following Species of Greatest Conservation Need are listed according to their level of association with the Oak Woodland natural community type, based on the findings in Wisconsin's 2015 Wildlife Action Plan.
Scores: 3 = high association, 2 = moderate association, and 1 = low association. See the key to association scores for complete definitions.
| Ants, wasps, and bees | Score | |
|---|---|---|
| Confusing Bumble Bee | Bombus perplexus | 1 |
| Rusty-patched Bumble Bee | Bombus affinis | 1 |
| Yellowbanded Bumble Bee | Bombus terricola | 1 |
| Beetles | Score | |
|---|---|---|
| A Leaf Beetle | Pachybrachis atomarius | 1 |
| A Leaf Beetle | Cryptocephalus cuneatus | 1 |
| A Pear-shaped Weevil | Coelocephalapion decoloratum | 1 |
| A Pear-shaped Weevil | Sayapion segnipes | 1 |
| Northern Barrens Tiger Beetle | Cicindela patruela patruela | 1 |
| Birds | Score | |
|---|---|---|
| Red-headed Woodpecker | Melanerpes erythrocephalus | 3 |
| Cerulean Warbler | Setophaga cerulea | 2 |
| Eastern Whip-poor-will | Antrostomus vociferus | 2 |
| Long-eared Owl | Asio otus | 2 |
| Worm-eating Warbler | Helmitheros vermivorum | 2 |
| American Woodcock | Scolopax minor | 1 |
| Hooded Warbler | Setophaga citrina | 1 |
| Least Flycatcher | Empidonax minimus | 1 |
| Northern Bobwhite | Colinus virginianus | 1 |
| Butterflies and moths | Score | |
|---|---|---|
| Columbine Dusky Wing | Erynnis lucilius | 1 |
| Grasshoppers and allies | Score | |
|---|---|---|
| A Spur-throat Grasshopper | Melanoplus foedus | 2 |
| Showy Grasshopper | Hesperotettix speciosus | 2 |
| Blue-legged Grasshopper | Melanoplus flavidus | 1 |
| Club-horned Grasshopper | Aeropedellus clavatus | 1 |
| Green-streak Grasshopper | Hesperotettix viridis | 1 |
| Grizzly Spur-throat Grasshopper | Melanoplus punctulatus | 1 |
| Handsome Grasshopper | Syrbula admirabilis | 1 |
| Mermiria Grasshopper | Mermiria bivittata | 1 |
| Plains Yellow-winged Grasshopper | Arphia simplex | 1 |
| Scudder's Short-winged Grasshopper | Melanoplus scudderi | 1 |
| Short-winged Grasshopper | Dichromorpha viridis | 1 |
| Speckled Rangeland Grasshopper | Arphia conspersa | 1 |
| Spotted-winged Grasshopper | Orphulella pelidna | 1 |
| Stone's Locust | Melanoplus stonei | 1 |
| Leafhoppers and true bugs | Score | |
|---|---|---|
| A Leafhopper | Cuerna sayi | 1 |
| A Leafhopper | Paraphlepsius nebulosus | 1 |
| A Leafhopper | Prairiana angustens | 1 |
| A Leafhopper | Flexamia prairiana | 1 |
| An Issid Planthopper | Bruchomorpha extensa | 1 |
| Yellow Loosestrife Leafhopper | Erythroneura carbonata | 1 |
| Mammals | Score | |
|---|---|---|
| Eastern Pipistrelle | Perimyotis subflavus | 3 |
| Big Brown Bat | Eptesicus fuscus | 2 |
| Franklin's Ground Squirrel | Poliocitellus franklinii | 2 |
| Northern Long-eared Bat | Myotis septentrionalis | 2 |
| Woodland Vole | Microtus pinetorum | 2 |
| Little Brown Bat | Myotis lucifugus | 1 |
| Silver-haired Bat | Lasionycteris noctivagans | 1 |
| Reptiles | Score | |
|---|---|---|
| Gophersnake | Pituophis catenifer | 3 |
| Gray Ratsnake | Pantherophis spiloides | 3 |
| Ornate Box Turtle | Terrapene ornata | 3 |
| Timber Rattlesnake | Crotalus horridus | 3 |
| Blanding's Turtle | Emydoidea blandingii | 2 |
| Prairie Ring-necked Snake | Diadophis punctatus arnyi | 2 |
| Prairie Skink | Plestiodon septentrionalis | 2 |
| Wood Turtle | Glyptemys insculpta | 2 |
| Butler's Gartersnake | Thamnophis butleri | 1 |
| Plains Gartersnake | Thamnophis radix | 1 |
| Slender Glass Lizard | Ophisaurus attenuatus | 1 |
Please see Section 2. Approach and Methods of the Wildlife Action Plan to learn how this information was developed.
Rare plants
The Natural Heritage Inventory has developed scores indicating the degree to which each of Wisconsin's rare plant species is associated with a particular natural community or ecological landscape. This information is similar to that found in the Wildlife Action Plan for animals. As this is a work in progress, we welcome your suggestions and feedback.
| Scientific Name | Common Name | Score |
|---|---|---|
| Agrimonia parviflora | Swamp Agrimony | 2 |
| Aplectrum hyemale | Putty Root | 1 |
| Asclepias purpurascens | Purple Milkweed | 2 |
| Besseya bullii | Kitten Tails | 3 |
| Camassia scilloides | Wild Hyacinth | 1 |
| Carex swanii | Swan Sedge | 3 |
| Dasistoma macrophylla | Mullein Foxglove | 2 |
| Desmodium canescens | Hoary Tick-trefoil | 3 |
| Desmodium perplexum | Perplexed Tick-trefoil | 2 |
| Hypericum prolificum | Shrubby St. John's-wort | 2 |
| Lespedeza violacea | Violet Bush Clover | 3 |
| Lespedeza virginica | Slender Bush Clover | 2 |
| Nyssa sylvatica | Black Tupelo | 1 |
| Prenanthes crepidinea | Nodding Rattlesnake-root | 1 |
| Quercus muehlenbergii | Chinquapin Oak | 2 |
| Rhus aromatica | Fragrant Sumac | 2 |
| Scutellaria ovata ssp. ovata | Heart-leaved Skullcap | 3 |
| Silene virginica | Fire Pink | 2 |
| Sisyrinchium angustifolium | Pointed Blue-eyed-grass | 2 |
| Spiranthes ovalis var. erostellata | October Lady's-tresses | 2 |
| Thaspium chapmanii | Hairy Meadow Parsnip | 2 |
| Thaspium trifoliatum var. flavum | Purple Meadow Parsnip | 2 |
Landscapes
The following Ecological Landscapes have the best opportunities to manage for Oak Woodland, based on the Ecological Landscapes of Wisconsin Handbook.
| Ecological Landscape | Opportunity |
|---|---|
| Southeast Glacial Plains | Major |
| Southwest Savanna | Major |
| Western Coulee and Ridges | Major |
| Western Prairie | Important |
| Central Sand Hills | Present |
| Central Sand Plains | Present |
| Southern Lake Michigan Coastal | Present |
Major (3 on map)
A major opportunity for sustaining the natural community in the Ecological Landscape exists, either because many significant occurrences of the natural community have been recorded in the landscape or major restoration activities are likely to be successful maintaining the community's composition, structure, and ecological function over a longer period of time.
Important (2 on map)
Although the natural community does not occur extensively or commonly in the Ecological Landscape, one to several occurrences do occur and are important in sustaining the community in the state. In some cases, important opportunities may exist because the natural community may be restricted to just one or a few Ecological Landscapes within the state and there may be a lack of opportunities elsewhere.
Present (1 on map)
The natural community occurs in the Ecological Landscape, but better management opportunities appear to exist in other parts of the state.
Threats/Actions
What are conservation actions?
Conservation actions respond to issues or threats, which adversely affect species of greatest conservation need (SGCN) or their habitats. Besides actions such as restoring wetlands or planting resilient tree species in northern communities, research, surveys and monitoring are also among conservation actions described in the WWAP because lack of information can threaten our ability to successfully preserve and care for natural resources.
Threats/issues and conservations actions for natural communities
Considerations
The following are additional considerations for Oak Woodland in Ecological Landscapes with opportunities for protection, restoration, and/or management. For more information, see the Wildlife Action Plan.
Southeast Glacial Plains
The Southern Unit of the Kettle Moraine State Forest offers some of the best management and restoration opportunities for oak openings and prairies in the upper Midwest. Oak woodland could be incorporated into savanna and prairie restoration projects, thereby providing a fuller representation of the variable conditions formerly characteristic of this region but also providing potentially viable habitat for some of the vulnerable “forest” species in this region. Other potential restoration and management sites occur within the joint TNC-WDNR Mukwonago River Watershed project (Walworth County).
Southwest Savanna
Some of the “pastured but never plowed” oak savanna sites that have been identified in this Ecological Landscape by WDNR Integrated Science Services staff may offer opportunities to restore and manage for savanna and oak woodland types. Additional survey work is needed to clarify the feasibility of initiating projects here.
Western Coulee and Ridges
There are many overgrown oak savanna remnants in this Ecological Landscape and restoration opportunities for both savanna and oak woodland are likely but not yet identified at the site level. Potential examples should be searched for on existing public lands such as Rush Creek Prairie State Natural Area (Crawford County), Fort McCoy Military Reservation (Monroe County), and Lower Chippewa River State Natural Area (Buffalo, Dunn, Trempealeau Counties).
Western Prairie
Some of the Waterfowl Production Areas and Wildlife Areas in this Ecological Landscape (e.g., Oak Ridge Lake Waterfowl Production Area (St. Croix County) may offer restoration potential for this community type.
Photos
Click to view a larger version. Please considering donating your photos to the Natural Heritage Conservation Program for educational uses. Photo use
Oak Woodland Photos
White oak woodland along the Mukwonago River, managed with prescribed fire to reduce shrub and sapling cover and encourage native grasses and forbs. Lulu Lake State Natural Area, Walworth County.
Photo by Eric Epstein.
Oak Woodland features high canopy closure but the dominant oaks retain distinctive limb architecture. Such vegetation is transitional between oak forest and oak savanna and can be managed at appropriate scales and in the right settings to benefit some forest interior species along with other species requiring or preferring more open conditions. Jefferson County.
Photo by Drew Feldkirchner.
Blue Spring Oak Opening, Jefferson County. Dominant trees are open grown bur oaks.
Photo by Eric Epstein.
Oak woodland with understory dominated by Penn sedge (Carex pensylvanica) but lead plant and other native prarie species are present, Monroe County.
Photo by Christina Isenring.
This Oak Woodland in Crawford County has been burned recently. Fires here have revealed the presence of rare plants that had been suppressed by the heavy shade created by dense growths of shrubs and saplings.
Photo by Eric Epstein.
Oak woodland with white oak, bur oak, and shagbark hickory. Governor Nelson State Park, Dane County.
Photo by Eric Epstein.
Note: photos are provided to illustrate various examples of natural community types. A single photograph cannot represent the range of variability inherent in a given community type. Some of these photos explicitly illustrate unusual and distinctive community variants. The community photo galleries are a work in progress that we will expand and improve in the future.
