Objective: Explain how the Superior National Forest in northern Minnesota used an Adaptation Workbook to integrate climate considerations and adaption actions into a forest restoration project along the North Shore of Lake Superior.
Author: Stephen Handler, Climate Change Specialist, US Forest Service Nothern Institute of Applied Climate Science
Publication Date: December 14, 2015
Prior to European settlement, the North Shore of Lake Superior was comprised of a healthy mixture of conifer-dominated forests. Logging in the late 1800s and early 1900s removed most of the white pine and white cedar, and the forest that grew back is heavily dominated by paper birch and quaking aspen. These forests are important for wildlife habitat, as regulators of stream temperatures, and as scenic elements of the North Shore.
Each year many tourists make the drive along scenic highway 61 which follows Lake Superior’s coast from Duluth, Minnesota, to the Canadian border ("Context Sensitive Design – Case Study 12," PDF). The tourists who make this trip and residents who live in the area year-round have noticed a striking change in the landscape in the last few decades. Current stands of birch and aspen have reached their typical age limits and nearly 80 percent of the birch forest along the North Shore are old and dying ("North Shore Restoration Project – Cover Letter" PDF). In addition, conifer regeneration is nearly absent in the understory of North Shore forests due to fewer older pine and cedar trees to provide seed, increased competition from native bluejoint grass and heavy deer browse. The decline of aspen and birch and the apparent lack of conifer regeneration have prompted attention and concern from many agencies and landowners in the region.
As a result, the Superior National Forest (SNF) like many other land managers in the area, is trying to restore forests in this landscape through active forest management. In 2013, SNF staff partnered with the State of Minnesota and the Grand Portage Tribe, as well as a broader group of stakeholders called the North Shore Forest Collaborative (NSFC), to begin developing the North Shore Forest Restoration Project. All partners shared the primary concern of restoring white pine, white cedar and other native plants to the area to ensure the health and resilience of the forest for which the area is renowned. For this specific project, SNF staff on the North Shore Interdisciplinary Team designed restoration treatments that would occur on SNF lands only.
Scenic Highway 61. Courtesy of
Paul Weimer, Flickr Creative Commons.
Early feedback on the SNF North Shore Restoration project indicated that it would be necessary to include a robust assessment of potential climate change impacts. As an entire agency, the USDA Forest Service is also working at multiple levels to address the challenges posed by climate change, and individual National Forests are being encouraged to design projects with climate adaptation in mind. The SNF invited the Northern Institute of Applied Climate Science (NIACS) to participate in a project planning meeting to help the team assess climate impacts on the goals of the project and design possible climate adaptation actions. NIACS coordinates the Climate Change Response Framework, a collaborative project to encourage climate-informed forest management, across the Midwest and Northeast.
The purpose of this case study is to demonstrate how coastal forests mitigate the effects of natural hazards like flooding, demonstrate how SNF used the Climate Change Response Framework to inform their forest management plans, and discuss how this case study will be used to begin engaging with private landowners in the area.
Coastal forests provide many critical ecosystems services to coastal communities in the Great Lakes region. They help to stabilize stream banks and reduce erosion, increase infiltration, attenuate flooding, improve water quality and provide habitat for culturally-significant wildlife like wolves, bears and moose ("North Shore animals"). In addition, Minnesota’s coastal forests support a thriving recreation and tourism economy, and many outfitters, restaurants and lodges cater to the tourists who frequent the area each year ("Tourism and Minnesota’s Economy," PDF).
In order to understand how the climate is changing and what impacts these changes can have on coastal forests, observed and predicted changes in climate must be described, as well as the implications these changes have on other factors that affect forest health like succession, biodiversity, invasive species and disturbance regimes.
Observed and Projected Changes in Climate:
Recognizing that climate change will significantly alter the landscape as we see it today, the SNF North Shore project team considered information from a recent climate change vulnerability assessment for northern Minnesota forests. Northern Minnesota has experienced substantial changes in temperature and precipitation over the past 100 years, and the rate of change appears to be increasing. A great deal of observed climate information is available for the project area and for the region.
Projected Change in Minnesota's Average Annual Temperature. Taken From: The Nature Conservancy, Climate Wizard.
A few notable climate trends include (Handler et al., 2014):
- Mean, minimum, and maximum temperatures have been increasing across all seasons, with winter temperatures experiencing the most rapid warming.
- The North Shore of Lake Superior has experienced more rapid warming than other areas in northern Minnesota.
- The North Shore project area has received more precipitation over the course of the 20th century, across all seasons.
- More rain has been falling in heavy precipitation events of three inches or greater.
- Snowfall has been decreasing across northern Minnesota, although there has been an increase in large winter storms.
- Climate change has also been indicated by trends in lake ice, growing season length and wildlife range shifts.
A few projected climate impacts that could be particularly important for the North Shore project area include:
- Temperatures in northern Minnesota are projected to increase across all seasons over the next century, with dramatic warming most likely in winter (2-12°F).
- Precipitation is projected to increase in winter and spring across a range of climate scenarios, but there is greater uncertainty for summer precipitation – slight increases or large decreases are possible.
- Intense precipitation events are likely to continue to become more frequent.
- Snowfall is projected to continue to decline across the assessment area, with more winter precipitation falling as rain.
Expected Climate Change Impacts:
Climate change has the potential to affect many aspects of coastal forests in northern Minnesota, including the way they function and the services they provide. In many cases, the potential exists for climate change to intensify challenges that these forests are already facing. Discussed below are some of the more notable issues and concerns.
Biodiversity describes the variability among living organisms. It can be used to describe diversity at the scale of ecosystems, species, ages or even genetics.Biodiversity at each of these scales is critical to forest resilience. Trees of different species and age perform distinct and complementary functions, some of which overlap. Individuals with different genetic traits may have different abilities to respond to new challenges or stresses. In general, having more diversity gives an ecosystem more potential options in the face of changing conditions (Elmqvist et al. 2003). This idea, response diversity, is important in northern Minnesota because many coastal forests have already experienced declines in diversity due to past management practices, fire suppression, development, deer herbivory and other causes. In northern Minnesota, the rate of climate change is predicted to outpace forests’ ability to naturally adapt. This has the potential to lead to a decline in forest diversity, making these areas more vulnerable to pests, wildfire and other potential threats. Read More…
USFS Staff Manage the Forest
Image courtesy of Stephan Handler.
Succession and Disturbances
In northern Minnesota, natural disturbances like wildfires have been suppressed in many forests by management activities. Although this is done largely to protect people and property in the area, this suppression has altered succession. As a result, many species that depend on wildfires have been aging and gradually being replaced by fire-intolerant species
Under climate change, extreme disturbances like wildfires, blowdowns, and pest outbreaks may act as a catalyst for rapid changes in forest composition. This is because these events frequently result in massive losses of trees and create large areas for uninterrupted regeneration of new plants. Trees that depend on disturbance and need lots of sunlight may be able to occupy these sites after disturbances. Post-disturbance openings might also provide opportunities for new mixes of species to colonize the area, including southern tree species.
Invasive and Nuisance Species
USDA Forest Service Climate Change Atlas Tool
If you are interested in exploring how climate change will alter the distribution of tree species throughout the Great Lakes region, the USDA Forest Service has created the Climate Change Atlas tool. This tool documents the current and possible future distribution of 134 tree species.
In addition to the previously listed stressors, climate change may also provide conditions that are more suitable for animals, plants and diseases that are threats to Minnesota’s northern forests. For example, warmer winters have led to increasingly large numbers of deer to survive each year. These large deer populations are feeding on many of the seedlings and saplings in the understory, and preventing robust regeneration of target browse species like white pine and cedar.
Invasive plant species like garlic mustard and buckthorn can disrupt forest ecosystems by changing the ground layer conditions for regeneration and competing for available moisture and nutrients. More disturbance and variable conditions expected under climate change are generally expected to benefit invasive species, which tend to be generalists and more opportunistic than native species.
New populations of insect pests, like aspen blotch miner, birch leaf miner, forest tent caterpillar, jack pine budworm, spruce budworm, and white pine tip weevil all have the potential to limit the growth of or kill many native trees in northern Minnesota. Warmer conditions and longer growing seasons can allow insect populations to build more rapidly during an outbreak, and insect attacks tend to be more damaging when they occur in forests that are already stressed due to droughts ("Minnesota Forest Ecosystem Vulnerability Assessment and Synthesis," PDF).
In summary, these climate trends point to a future that is warmer and more variable, presenting greater stress for boreal species such as paper birch, white spruce and balsam fir. The steep terrain and shallow soils along the North Shore make the area more susceptible to flooding from heavy rain events, as was experienced in the summer of 2012. Conversely, the southern aspect, warmer conditions, thin soils and longer growing season could combine to make water stress more challenging for forests in this landscape. High deer populations mean that many preferred browse species (white pine, oak species, etc.) may have a hard time establishing without protection from herbivory ("Minnesota Forest Ecosystem Vulnerability Assessment and Synthesis," PDF).
Forestry requires landowners and natural resource managers to plan over long time scales. Trees take several decades to establish and grow to maturity, so management actions taken today will have effects long into the future. Even without considering climate change, forestry requires managers to grapple with the uncertainty of large-scale disturbances (fire, wind and forest pests), market demands for different forest products and competing demands for other land uses. Now that it is increasingly clear that climate change effects are already occurring and will likely continue through this century, foresters need to consider how future climate conditions will affect their ability to meet their management goals.
NIACS has developed a flexible process to help forester managers and landowners address climate change called Forest Adaptation Resources (FAR). This process includes an Adaptation Workbook, which asks forest managers to consider a series of questions to focus their thinking on potential climate impacts and adaptation actions for a particular project with real-world management goals (Figure 1).
Figure 1: The basic five-step process outlined in Forest Adaptation Resources, which starts with the particular management goals a landowner or forest manager has for a particular project area (modified from Swanston and Janowiak; 2012).
During a two-day workshop in April 2013, NIACS led a discussion among the SNF staff involved in planning the North Shore Forest Restoration Project. This team outlined the major goals of the project and considered how a range of broad-scale projected climate change scenarios might affect the particular landscape along the North Shore. Information on climate change was presented from the Minnesota Forest Ecosystem Vulnerability Assessment mentioned above, and team members used their own local knowledge and expertise to consider how specific aspects of the project area would amplify or reduce the general projections. Then the team thought critically about how climate change might present challenges and opportunities for their management goals, and brainstormed a wide range of adaptation tactics that could address expected climate impacts. A "menu" of adaptation actions from the FAR document helped the team generate specific ideas. Finally, the team discussed key monitoring items that would be helpful to determine if adaptation actions were effective. Table 1 shows an example of the thought process from the FAR document (Swanston and Janowiak; 2012).
Table 1: A simplified illustration of how the project team used the Adaptation Workbook.
1. Define project area, management goals and timelines.
This information was specified in the Proposed Action for the North Shore Forest Management Project. The team listed their specific management objectives for several forest types, all of which are targeted to be completed over the next 10-12 years.
Example management objective: Regenerate paper birch on up to 1,000 acres using clear cuts with reserve areas.
2. Assess climate change risks and opportunities for the project.
A great deal of information was pulled from the Minnesota Forest Ecosystem Vulnerability Assessment and Synthesis document. The team considered broad-scale trends and then discussed how climate change impacts might be affected by the specific conditions in the project area.
Example: Across northeastern Minnesota, paper birch is projected to have 13-77 percent less suitable habitat by the end of the century, across a range of climate scenarios. The proximity of this project area to Lake Superior may moderate some of the expected changes in temperature and precipitation.
3. Evaluate management objectives in light of climate change information.
The team thought critically about how climate change might present challenges and opportunities for their management objectives, and decided whether those objectives were still feasible.
Example: Although paper birch is projected to decline over the long term, the team decided that the feasibility of regenerating paper birch in the short term was still high. They decided to go forward with this objective, because adding a young age class of paper birch would also give this species more opportunity to persist over the next several decades.
4. Identify adaptation approaches and tactics.
The team used the "menu" of adaptation approaches and strategies in the FAR document to brainstorm a list of possible adaptation tactics for each forest type and management objective.
Example: Identifying the best possible locations to retain paper birch on the landscape for the long term, including stands of healthy paper birch, areas with north-facing slopes and cold pockets.
5. Monitor and evaluate effectiveness of the selected actions.
The team discussed key monitoring items that would be helpful to determine if adaptation actions were effective. They focused on monitoring actions that are already required for National Forests.
Example: Standard stocking surveys can determine if regeneration in harvested stands is up to par. These surveys can also be used to detect if regeneration becomes more difficult over time or in certain stand types compared to others.
After going through the Adaptation Workbook, SNF staff continued to think about possible adaptation actions and refine the North Shore Forest Restoration Project. Importantly, the team recognized that many of the management actions they already had planned also had benefits for climate change adaptation. Also, northeastern Minnesota may turn out to be one of the best possible "refuge" areas in the region for boreal species like paper birch and white spruce. Therefore, the team ultimately decided to proceed with many of the original goals and objectives of the project. Several modifications were added to increase diversity and future management flexibility, and some of these included:
- Identifying the best possible locations to retain paper birch on the landscape for the long term, including stands of healthy paper birch, areas with north-facing slopes and cold pockets.
- Identify stands of old, poor-quality paper birch for restoration to other appropriate native or climate-adapted forest types.
- Increasing the proportion of planted white pine, species expected to fare better under climate change.
- Planting additional native species that are present in the surrounding landscape that were not originally part of the project design, including bur oak and northern red oak.
- Try a variety of deer herbivory protection strategies – fences, tree cages, bud caps and/or repellant sprays.
Adding these adjustments to the original proposed action will help the Superior National Forest restore forest cover along the North Shore, and accomplish the objectives of restoring native vegetation communities, improving wildlife habitat, improving watershed health, providing sustainable timber products and reducing hazardous fuels.
The North Shore Forest Collaborative has been engaged in discussion about climate change and adapting/creating a resilient forest ecosystem. In 2013, NSFC hosted a workshop (PDF) for landowners interested in restoring their property along the North Shore. Approximately 60 people came to the event, which featured keynote speaker Casey McQuiston, a soil scientist for the US Forest Service. At this workshop topics such as climate change impacts on the North Shore forest, vulnerability assessments and specific tactics the Forest Services is considered to increase resiliency were highlighted. The NSFC has also invited Minnesota Sea Grant staff to provide climate change training and to present on strategies for engaging private landowners to their members. In addition, the technical committee of the NSFC has begun working on documents that describe the desired future condition of the forest at a finer scale and is incorporating climate change considerations into those documents. The Northern Institute of Applied Climate Science will be partnering with the NSFC and adjacent landowners as they implement the Superior National Forest’s North Shore Restoration Project. And as the NSFC works to expand on these efforts on their own private land by applying for grants together, and coordinating contracts to implement the work. Natural Resource Conservation Service has been working to implement similar strategies on private land.