Lake Tomahawk Demonstration Area, Oneida County, Wisconsin

About Lake Tomahawk Demonstration Area

This demonstration area is part of the Northern Highland-American Legion (NH-AL) State Forest, at 225,000 acres the largest state forest in Wisconsin. Established in 1925, the forest protects the headwaters of the Wisconsin, Flambeau, and Manitowish rivers in the northern part of the state. The Wisconsin Department of Natural Resources manages the land.

Upland habitats support a mix of pines, spruce, fir, and northern hardwoods including birches, maples, ash, and aspen. Most of the forest is young to middle-aged: 20 to 80 years. About 30 percent of NH-AL is managed to regenerate timber stands dominated by aspen and white birch through the use of clearcut and shelterwood harvests on 45- to 60-year rotations.

Visitors use the forest for camping, canoeing, hiking, birdhing, snowmobiling, biking, and hunting. A broad diversity of wildlife inhabits the tract.

Improving the Land for Woodcock

Foresters have supervised numerous logging jobs in the last 20 years, and many forest stands on NH-AL currently provide feeding, brood-rearing, and nesting habitat for resident and migrating woodcock. Around 4,500 to 5,500 acres are logged each year across the property, in both thinning/selective harvest and regeneration-oriented harvests.

Forest Compartment 30, southeast of Lake Tomahawk, is managed as young-forest habitat. Most of the approximately 1,000 forested acres in this compartment are dominated by aspens; stands range across the full successional spectrum from very young to mature and senescing. The goal is to break up large blocks of even-age aspen to create more age-class diversity within the forest while providing habitat for woodcock, golden-winged warblers, ruffed grouse, and other young-forest wildlife.

Soon after this photo was taken, managers mowed and sheared this woodcock singing ground to suppress invading birch, pine, sweet fern, and briars.

Because so many different forest age classes already exist, the entire compartment is considered a demonstration area.

Two stands in particular, of 74 and 45 acres, are scheduled to be harvested over the next several years. In 2010 managers removed small trees and other vegetation – white birch, seedling pine, sweet fern, and briars – in improving or creating nine wildlife openings. Male woodcock will use the openings as singing and display habitat. A network of trails have been mowed and widened. (The trails will also function as singing grounds.)

In a low zone along the Wisconsin River, managers have begun to renew older stands of alder. In a smaller wetland area, four 50- to 100-foot-wide strips were mowed in 2010. Alder in a nearby larger wetland will be harvested as soon as an adjacent aspen stand is cut, providing access. Woodcock will use the rejuvenated alder on these damp-soil sites for feeding and daytime resting.

A map depicts recent management efforts on the demonstration area.

Science

WMI biologist Amber Roth monitors a golden-winged warbler study site in the demonstration area. During the spring and summer breeding season, five to six males regularly hold territories on a 40-acre, 11-year-old (as of 2010) aspen clearcut done as a pine-retention treatment. (Other male golden-wings defend territories elsewhere on the demonstration area, including along a transmission line right-of-way and in other clearcuts.)

Biologist Amber Roth uses mist nets to capture golden-winged warblers in a study of the species conducted on Lake Tomahawk Demonstration Area.

The site is attractive to golden-winged warblers because its dense shrub layer is interspersed with grassy patches and scattered residual canopy trees that were not cut during the last clearcut harvest; male golden-wings use the trees as song perches.

Though golden-wings typically nest in very young forest, they may feed and rear their fledglings in somewhat older forests and in a variety of forest community types. Thus for this species, and for others, maintaining an age range of aspen and a diversity of forest types on the landscape likely are important habitat-management aspects.

All male golden-wings on the study site have undergone mitochondrial DNA testing between 2007 and 2010, and only one male (in 2007) was found to be a cryptic hybrid. (A cryptic hybrid appears to be a pure golden-winged warbler, based on plumage characteristics, but is actually not genetically pure: i.e., an ancestor interbred with a blue-winged warbler.)

The most abundant associated bird species on this site (in order of abundance from high to low) are chestnut-sided warbler, indigo bunting, rose-breasted grosbeak, veery, and white-throated sparrow.

Male golden-winged warbler before banding.

Across the demonstration area, and across aspen forest of all ages, the most abundant bird species (in order of abundance from high to low) are ovenbird, chestnut-sided warbler, veery, red-eyed vireo, and rose-breasted grosbeak. Retaining white and red pine in aspen forests here has likely benefited conifer-loving species like the pine warbler and black-throated green warbler.

All of these species are migratory, and some are Neotropical migrants that spend the winter in Central and South America. Only two of the ten most abundant species are year-round residents – black-capped chickadee and blue jay – which suggests that aspen forests in this area provide a crucial breeding habitat for migratory birds.

Other Species of Greatest Conservation Need observed on the demonstration area include whip-poor-will, yellow-bellied sapsucker, veery, ovenbird, rose-breasted grosbeak, and white-throated sparrow.

Funding and Partners

Wisconsin Department of Natural Resources, North Lakeland Discovery Bird Club, Ruffed Grouse Society, Wildlife Management Institute

How to Visit

From Wisconsin Route 47 south of Lake Tomahawk, turn east on Lyannis Road. A drivable road along an old railroad grade, parallel to a utility line right-of-way, runs north-south the length of the demonstration area. Two logging roads (one drivable with high-clearance all-wheel-drive vehicles, and one walkable) lead east through the demonstration area toward the Wisconsin River. Multiple logging roads wind through the compartment, giving access to different-aged forest tracts.

For more information on the Northern Highland-American Legion State Forest, see http://dnr.wi.gov/forestry/StateForests/SF-NH-AL/

Foresters overseeing management of Forest Compartment 30 work out of the Wisconsin DNR office complex in Woodruff, WI. For detailed information contact forester Craig Dalton at craig.dalton@wisconsin.gov.

WMI contract biologist Amber Roth can be contacted at PO Box 589, South Range MI 49963, phone (906) 483-2190, amberroth33@yahoo.com.