Wisconsin Dept. of Natural Resources: Caroline Lake State Natural Area


Staff from the Wisconsin DNR completed the Adaptation Workbook in 2014, and they generated several ways to incorporate adaptation considerations into the management and monitoring at the Caroline Lake State Natural Area. No management actions are imminent, but monitoring at the site continues.

Staff from the Wisconsin DNR completed the Adaptation Workbook for a 500-acre State Natural Area at the headwaters of the Bad River in northern Wisconsin.

Project Area

The Caroline Lake State Natural Area (SNA) is one of almost 700 protected areas across the state. SNA's are specifically chosen to represent outstanding examples of Wisconsin's native landscape of natural communities, significant geological formations, and archaeological sites. Natural areas are managed passively for research and educational use, the preservation of genetic and biological diversity, and to provide benchmarks for determining the impact of use on managed lands. The Caroline Lake SNA was designated in 2002, and it was selected because of its position at the headwaters of the Bad River, which eventually replenishes the water of the Kakagon/Bad River Sloughs. The Caroline Lake property spans 539 acres, containing numerous high-quality plant communities including northern wet forest, northern dry-mesic forest, northern sedge meadow, shrub carr, and open bog. The extensive forested wetlands of this site are an important nesting area for several warbler species. Common loons, osprey, and bald eagles have been observed at the site.

Management Goals

Wisconsin DNR forestry staff leading a field tour at Caroline Lake SNA.

For this project, DNR staff considered the 407 acres of the Caroline Lake SNA that are forested. The overall management at SNAs is mostly passive, allowing SNAs to serve as a baseline of natural undisturbed ecosystems.  The management objectives for this property include: 

  1. Retain reserve/legacy trees as groups or individuals throughout the property within harvested stands.
  2. Manage the older stands at the site as a reserve for northern mesic/wet-mesic/wet forest, northern sedge meadow, an aquatic reserve and wetland protection area, and as an ecological reference area. Natural processes will determine the structure of the older forest and wetlands.
  3. Increase tree species diversity by increasing representation of hemlock, yellow birch, white cedar, white pine, basswood and white ash.

Climate Change Impacts

Hemlock regeneration at Caroline Lake SNA.
For this project, the most important anticipated climate change impacts include:
Milder winters could increase deer populations and deer browse on species like hemlock and cedar
Warmer conditions could be beyond the tolerance of boreal or northern species

Adaptation Actions

Project participants used the Adaptation Workbook to develop several adaptation actions for this project, many of which were based on the concept that the SNA is serving an important role as a climate refugia for northern species, and also that the SNA could act as a "baseline" to compare the effects of climate change on unmanaged stands compared to managed stands elsewhere on state land. Some specific adaptation ideas that the DNR developed for Caroline Lake include:

Entire Property
4.1. Prioritize and maintain unique sites.
Continue to maintain some unmanaged “benchmark” areas for comparison to managed stands.
Reserve and protect pockets of hemlock to serve as refugia for that species.
Northern Hardwoods - Passive Management
5.3. Retain biological legacies.
Create or maintain large nurse logs to promote hemlock germination.
Northern Hardwoods - Active Management
5.2. Maintain and restore diversity of native species.
Diversify tree species and age classes by selecting against sugar maple and promoting mid-tolerant species such as white pine, yellow birch, black cherry, basswood and ash through increasing gap sizes in harvested areas.
Aspen Stands
9.1. Favor or restore native species that are expected to be adapted to future conditions.
9.2. Establish or encourage new mixes of native species.
Actively manage for conversion by extending rotation age to gradually reduce the pioneer species component
Planting desired hemlock-hardwoods species, and those species such as red oak, white pine, black cherry and basswood that better tolerate warming and deer browse


Project participants identified several monitoring items that could help inform future management, including:
Natural regeneration of priority species such as cedar, hemlock, and swamp hardwoods.
Hydrological changes in peatland systems on the property

Project Photos

Click to enlarge photos

Map of the Caroline Lake SNA.
Fall color at the Caroline Lake SNA. Photo credit: Robert Kleppin.

Project Documents

Next Steps

Monitoring and management will continue at Caroline Lake SNA. DNR staff have suggested formally amending the SNA's management plan language to include climate change adaptation as a rationale for including more active management on the property in certain instances.

Learn More

To learn more about this project, contact Stephen or learn more at: http://dnr.wi.gov/topic/lands/naturalareas/index.asp?SNA=336


Lowland/ wetland conifers, Lowland/ bottomland hardwoods, Upland conifers, Upland hardwoods, Refugia

Last Updated

Thursday, November 3, 2016