In recent months, we couldn’t help but hear about climate change, from Pope Francis to President Obama to world leaders gathered in Paris. What does it mean to our Minnesota forests and their creatures, and most importantly, what can we do about it?
But Climate Has Always Changed
Our Earth and forests are ever-changing. So is our climate. The pace of this change usually happens slowly over hundreds, thousands or millions of years allowing our forests and their creatures to adapt. Much of Minnesota was glaciated just over 10,000 years ago. So what’s different this time? Scientists have noticed the Earth’s overall average global temperature has warmed in the last 150 years, and it’s happening faster than past changes. About 40% more carbon dioxide has been added to the atmosphere since the Industrial Revolution in the mid-1700s. The most recent decade was the warmest since instrumental record keeping began around 1880. Abundant evidence shows it’s primarily the result of human activity. Our burning of fossil fuels for heat and energy is releasing greenhouse gases such as carbon dioxide, trapping heat in the atmosphere.
Warmer, Stormier, and a Changing Forest
Depending on our future emissions levels, scientists predict the Earth’s average temperature to rise another 3 to 12 degrees by 2100. Minnesota is projected to have increases in annual average temperature of 9 degrees Fahrenheit (most notably in winter). Overall precipitation could increase by 3-5 inches, but in the form of more frequent, intense rain and wind events, with periods of severe drought. Increases in disturbances such as blowdown events, wildfire and erosion are expected. Snowfall could be reduced by 30 % and snow depth by 40-60 %. The growing season may increase by 35-49 days.
Minnesota is unique in its diversity of biomes including grassland, deciduous forest and coniferous forest. They have been shaped by differences in temperature and precipitation, from north to south and east to west, creating a tension zone and causing many of our forest plants and wildlife to be at the edge of their range. As climate changes occur, their ranges will shift north and east. Species that will struggle the most to adapt or migrate will be those with isolated habitats, very specific habitat requirements, low reproductive rates, limited dispersal, dependence on interactions with specific other species, low genetic variability, and/or living near their physiological tolerance limits.
Our forest ecosystems, economy and recreation may be altered in many ways. Stressed trees will be more susceptible to insects and disease. Invasive and non-native plants and pests that thrive in the new conditions may increase. An example is the eastern larch beetle which effects tamarack and fares better in warmer weather. Northern tree species such as balsam fir, spruce, tamarack, quaking aspen, and paper birch will likely decrease and be replaced by oak, hickory, elm and maple. Lake trout and cisco will be negatively affected by warmer lakes. Less snow and coniferous cover will not bode well for spruce grouse and marten. Moose likely already feel the impact of warmer temperatures and loss of energy spent staying cool. White-tailed deer may benefit from greater access to forage and reduced energy loss in winter. However, as their abundance increases, potential impacts to crops and forest vegetation could be felt. And possible effects of increase in disease outbreaks under new temperature and precipitation patterns, like epizootic hemorrhagic disease, should be considered. Activities from timber harvest to maple syrup-ing, and fishing to snowmobiling will “feel the heat”.
What Can We Do? – Grow Diverse and Resilient Forests
While climate change may seem overwhelming, the good news is we can take action. Mitigation, or reducing carbon emissions, is our first opportunity. It includes familiar activities such as turning the thermostat down and lights off, driving less and using more efficient vehicles, using renewable heat and energy sources, and planting trees to shelter our homes.
In addition to mitigation, as a forest owner, you have a second vital opportunity – adapting to climate change by managing your forest for diversity and resilience. The four steps you can take are:
- Prepare – Learn more about climate change, identify potential threats and vulnerabilities to your forest, and share with and encourage others.
- Plan – Gather basic information about your forest, establish goals, and identify where climate change may impact it.
- Apply key strategies – Implement on-the-ground practices to meet your goals. (More detail to follow.)
- Monitor and adapt – Track your efforts and adjust your strategies as needed.
Key Adaptation Strategies
Your goals, and the adaptation strategies to address them, could include the following. You may already be applying some of these tangible, on-the-ground practices:
- Forest health – Encourage native trees and plants, especially those predicted to thrive in the new conditions; consider harvesting trees expected to be most vulnerable sooner rather than later and occasional thinning to decrease competition and increase vigor of remaining trees; be on the watch for invasive plants and control them promptly; and maintain a diversity of native trees, sizes and age classes so your “eggs are not in one basket”.
- Wildlife habitat – Maintain and restore native forest habitats; buffer and protect wetlands and streams; and maintain refugia, habitat structure and connectivity, and large undeveloped, un-fragmented forest habitat blocks.
- Water quality – Minimize disturbance to water bodies and wetlands; restore shorelines to native vegetation; and maintain watershed health by keeping it forested.
- Carbon storage – Grow and retain trees on site; minimize soil and tree damage during harvest; and use trees in long-lived wood products.
- Recreation – Create low-impact trail systems; monitor and repair trails after large storms; and encourage deer management to control populations and protect forest vegetation from over-browsing.
- Human health and safety – Manage wildfire risk by being Firewise and reducing fuel load around your home and forest; and maintain safe trails by closing or re-routing them when threats such as hazard trees or unsafe crossings exist.
For greater detail on adaptation strategies, see the Weather-Wise Worksheet for Woodland Owners. Though it refers to forests in New England, the strategies are also very relevant to our Minnesota forests. Please consider using it with your professional forester to integrate climate change goals and strategies into your forest stewardship planning and management, taking action to keep your forest healthy, diverse and resilient far into the future. Your forest, its creatures and you will be glad you did!
For more information on climate change, see the DNR web page at http://www.dnr.state.mn.us/climate/climate_change_info/overview.html
Photo by Philip Potyondy