The role of fire in forest ecosystems
Most people learn early on in life that fire is a bad thing, having been warned of its dangers by their parents, or perhaps learning the lesson first-hand from sitting a little too close to a campfire.
Most people learn early on in life that fire is a bad thing, having been warned of its dangers by their parents, or perhaps learning the lesson first-hand from sitting a little too close to a campfire. For a long time in our country, forest managers also had a similar belief: that forest fires were always detrimental to the ecosystems they were managing, and needed to be extinguished as soon as possible.
This stance by our forest managers was significantly driven by experiences our country had with catastrophic fires in the late 1800’s and early 1900’s. Most notably, the Peshtigo Fire in Wisconsin , in 1871, which took the lives of over 1,500 people, making it the deadliest forest fire in U.S. history. Devastating fires such as these helped shaped attitudes (and forest management strategies) for decades to come.
However, as forest managers and ecologists learned more about the role of fire, management strategies began to change. After the Yellowstone fires in 1988, which burned over 1,200 square miles, the benefits of allowing forest fires to burn were starting to be understood.
Fire is a natural part of many forest ecosystems, occurring in regular intervals that vary depending on the forest type, forest understory, climate, soil type, and other factors. Natural forest fires are typically started by lightning during the warm and dry seasons, which range from the snowmelt period in spring through the fall. Historically, since these lightning-caused fires occurred at regular intervals, they were successful in clearing out old, dead, and/or decaying vegetation bit by bit. Old vegetation was continually being recycled into new growth.
When these types of fires are suppressed, the result is a build-up of fuel. Over a period of years, more and more fuel accumulates, setting the stage for a catastrophic event, such as what occurred in Yellowstone in 1988. The Peshtigo Fire was also largely a result of the excessive accumulation of fuel, mainly through logging slash left from the extensive logging that took place during that time period.
Besides preventing catastrophic fires, periodic, smaller-scale forest fires have positive effects on many habitat types. Fire clears out old and overgrown vegetation, and recycles nutrients back into the soil. Additionally, many species have evolved to co-exist with fire. For example, in Michigan, jack pine trees are considered a fire-dependent species—their cones are tightly held together with a glue that only opens with high temperatures, which are typically only produced through fire.
Today, one of the ways to safely balance the role of fire with the encroachment of people and structures into forestland is through prescribed fire. Prescribed fire is when forest managers purposely set a fire to reduce fuel loads or obtain some other management objective. They are only undertake during optimal weather conditions and with the utmost safety protocols in place. Prescribed fire is a tool that allows forest managers to mimic the historic benefits of wildfire, while maintaining a safer, more controlled strategy.
Visit Michigan State University Extension to learn more about forests and forest management.