The Nature Conservancy: Adaptation Forestry in Minnesota's Northwoods

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Evaluation

This project was funded by the Wildlife Conservation Society in 2012, and planting occured in the spring of 2013 and 2014 across several sites in northeastern Minnesota. TNC and the University of Minnesota-Duluth are coordinating monitoring of this project over time.

The Nature Conservancy is coordinating this project, in collaboration with NIACS, University of Minnesota-Duluth, and other organizations. The project is being implemented on approximately 2,000 acres of forestland in northeastern Minnesota, on a mix of federal, state, and county land. Project partners are creating examples of climate change adaptation that feature a combination of management practices and planting to increase ecosystem complexity. This project has been supported by a grant from the Wildlife Conservation Society and its Climate Adaptation Fund. The Doris Duke Charitable Foundation supported the establishment of the Climate Adaptation Fund.

Project Area

Adaptation actions have been implemented across 2,000 acres of forestland in northeastern Minnesota, on a mix of Federal, State, and County-owned land. Project partners included the Superior National Forest, Minnesota Dept. of Natural Resources, St. Louis County, and Lake County. The project included action on 500 acres of each of these common forest types: Boreal Mixed, Mesic Pine, Dry-Mesic Pine, and Hardwood-Conifer.

Management Goals

Chris Dunham (TNC) walks through a project site with large white pine retained as seed trees.

This project was designed specifically to demonstrate and test climate-informed management practices designed to make forests more resilient in the long-run. In the Great Lakes region, conventional forestry practices have emphasized simple stand structures through even-aged management practices. Aspen has tended to benefit across much of the landscape. The focus of this project, consists of a combination of management practices to increase ecosystem complexity:

  • Managing for a range of species with a diverse array of life history traits (e.g., shade tolerance, drought and fire). A full spectrum of traits translates to a better ability to respond favorably to new climate conditions
  • Managing for a multi-aged forest using partial harvest methods.
  • Planting a suite of climate-adapted tree species (bur oak, red oak, white pine, and basswood). TNC chose these species because ecological modeling suggests they are likely to thrive under warmer, drier conditions. All four species are native to the region, but uncommon due to a legacy of past harvesting practices, a climate that historically favored boreal species, and dispersal limitations. 

Climate Change Impacts

Much of current forest management in northeastern Minnesota focuses on maintaing and restoring native boreal species, such as aspen and white spruce. At the same time, forest composition in northeastern Minnesota is projected to change as the climate changes, and recent research suggests that these same species are at greater risk in a changed climate. These anticipated changes suggest that, in the long term, climate change may be working in direct opposition to some current restoration management actions. Modeling studies project changes in forest composition in northeastern Minnesota under future climate scenarios, including a shift towards more maple and a less diverse forest composition across the northern forested landscape. This suggests that many of the tree species that are currently a focus of restoration efforts (white spruce, aspen, paper birch), with the exception of white pine, may be unsuited to future conditions compared to more southerly distributed species, such as maples, basswood, and oaks.

Adaptation Actions

This project was designed with several adaptation practices in mind:  

  • Promoting diverse age classes 
  • Retaining biological legacies

 

Area/TopicApproachTactics
Planting
5.2. Maintain and restore diversity of native species.
9.1. Favor or restore native species that are expected to be adapted to future conditions.
Project partners planted almost 109,000 seedlings across the various project sites. Bur oak, northern red oak, white pine, and basswood are all native to northern Minnesota and expected to be favored by future climate conditions.
8.1. Use seeds, germplasm, and other genetic material from across a greater geographic range.
Seedlings of each species will come from 2 distinct seed zones in Minnesota, plus a third seed zone in lower Michigan for white pine.
9.4. Protect future-adapted seedlings and saplings.
Seedlings were protected from deer herbivory with a combination of bud caps and tree tubes.
Forest Management Practices
5.1. Promote diverse age classes.
5.3. Retain biological legacies.
Planting sites were selected because they had recently employed partial harvest methods such as patch clearcuts and group selection. Large seed trees and snags were retained at each site.

Monitoring

A subset of the project sites, including 4,600 seedlings, were designed as replicated studies. Follow-up monitoring is being coordinated in partnership between TNC and the University of Minnesota-Duluth. Monitoring variables include: and n May 2014, in addition to monitoring survival, growth, phenology, and other factors.
Survival and growth of planted seedlings, particularly comparing seedlings from southern seed zones to local seed zones.
Phenology of planted seedlings, such as leaf-out dates.
Morphology of planted seedlings

Project Photos

Click to enlarge photos

Project Videos

Preparing the Northwoods for an uncertain future (Produced by the WCS Climate Adaptation Fund

Next Steps

Monitoring data from the first few seasons has yielded some encouraging results. Seedling survival from all seed zones was over 80% over the first winter. Bur oak seedlings seem to have higher survival rates than northern red oak, but northern red oak seedlings are growing faster. Project partners have organized several field tours and presentations to share the results of this project, and these efforts will continue.

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Keywords

Upland hardwoods, Assisted migration, Genetic diversity, Planting, Research

Last Updated

Wednesday, November 2, 2016