Helping Minnesota’s Forests Transition to a Warming Climate

Ecolution reporting made possible by Seward Co-op, which has been a community-owned grocer since 1972: Together, we continue to cultivate a cooperative economy.

Julie Etterson (third from left) collects seeds with her students. Courtesy photo

I spent my childhood slopping through the swamps and woods behind our house in Littlefork, Minnesota, near the Canadian border. Some of my earliest memories revolve around the springtime joy of stumbling upon a pristine white bloodroot flower emerging from the mud, a dazzling yellow patch of marsh marigold, or a turtle. So it may seem natural that I ultimately became a biology professor. However, my career pathway was circuitous.

Turned off by high school biology, I majored in international studies in college. I was interested in how our cultural lenses shaped environmental policy. After graduation, I worked for several years as an environmental advocate and educator. Gradually, I realized that I needed to deepen my scientific understanding to be a more effective proponent of change. So, I returned to college for a second degree, got a taste of doing research as an undergraduate, and dreamt up questions that formed the basis of my PhD thesis and the foundation of my career today.

For the last 30 years, I have been studying whether wild plant populations can adapt quickly enough to keep pace with climate change. After numerous short-term experiments (i.e., three to five years, the length of a grant funding cycle), my general conclusion was no, they cannot, although it was clear to me that longer-term experiments would be better to answer this question.

Fortunately, a group of evolutionary biologists and seed storage experts were also thinking about long-term experimentation. Together, we established Project Baseline, a seed collection, to test evolutionary rates across time and space. Basically, we built a time capsule of seeds. Almost ten years ago, we collected seeds of wild plant species across their geographic ranges and stored them at the USDA seed storage facility in Fort Collins, Colorado. Now researchers can withdraw the ancestral seeds from the seed bank, collect contemporary seeds from the same location, and grow them side by side to directly observe evolutionary changes that have occurred over time in the contemporary populations. As the seed bank ages, the differences between old and new collections will become more pronounced and we can dissect the mechanisms of adaptation.

Moving Minnesota’s Forests

Most recently, I have turned my attention to the here and now. In northeastern Minnesota, we already see declines in some dominant tree species of the mixed boreal forest. Although this is sad, it is also an opportunity to take action. Habitat gaps left from tree mortality, due to drought, storms, or pests, are vulnerable to invasive species. But we can fill these natural habitat gaps, or those caused by other human activity, with trees that have a better chance of surviving into the future as the climate continues to change.

At present, the climate in northeastern Minnesota is more similar to that of the Twin Cities 20–30 years ago. That is about a 150-mile northerly shift in the climate envelope. Assuming that trees are adapted to climate, which decades of research supports, populations that will thrive in the Arrowhead Region now are the ones that currently live further south. Moving species and their climate-adapted populations in the direction of climate change is often referred to as “assisted migration.” My colleagues at the Nature Conservancy and I tested this hypothesis to confirm that this strategy would help forests transition as climate continues to change around them.

Other organizations and some state and county forestry departments, such as North Shore Forest Collaborative, Minnesota Power, and the U.S. Forest Service, have also been exploring and testing this approach for future implementation.

It is becoming increasingly important to me to help people find ways to feel empowered to combat climate change to avoid feelings of despair and resignation. I feel the burden of ecoanxiety in the voices of the younger generation — from my students and my own kids. This has been a motivational force for me to think of ways people can participate in the solution. To this end, over the last few years, I have collaborated with a broad range of partners, especially the Nature Conservancy, on a project we are calling Minnesota Million. Our goal is to plant one million acres of “climate-smart” trees in Minnesota by the year 2045.

We have two main goals. First, the more trees there are, the more carbon is captured from the atmosphere and stored in the plant body, which can make a dent in our carbon emissions. Second, we can use this project to plant trees that have a better chance of surviving into the future. In other words, we can also do assisted migration while we are doing forest restoration and climate remediation.

Our state doesn’t grow enough tree seedlings to meet this demand, so we are building partnerships with youth groups and other citizens to collect tree seeds from more southern sources. We are recruiting farmers, tribal nurseries, and student groups to grow the seedlings that are necessary to achieve our long-term goals. We consider ourselves to still be in our infancy, but we are growing and will be planting over 100,000 tree seedling plugs in spring 2024. MN Million is a young but growing movement that will provide a mechanism for people to become a part of the climate solution.

The Minnesota climate is changing, and the forests that we expect to see at our favorite state parks or other wild areas will change too. We can either stand on the sidelines, watch the natural processes of mortality and replacement take place, and hope that invasive species don’t fill the gaps. Or we can take proactive action to facilitate forest community change while also increasing the capacity of our forests to serve as the lungs of the planet.


Find out how to become involved with MN Million as a seed collector or grower at climatesmarttrees.com

Dr. Julie Etterson (she/her) is a Distinguished McKnight University Professor and director of the Institute on the Environment at the University of Minnesota Duluth.