Over the next 100 years, Wisconsin’s climate is expected to undergo changes that may significantly impact forest communities across the state. Today, more than 150 years since its formation, the Menominee Reservation remains one of the most densely forested parts of Wisconsin. In fact, there are more trees today than before the Menominee mill was built; it has prepared more than 2 billion board feet (4.7 million cubic meters) of timber for sale over the years. The health of the Menominee Forest can be attributed to a long-term strategy practiced by its tribal forest managers. This strategy, called sustained yield, requires that growth balance what is removed from the forest. The practice is aligned with the Menominee goal of thinking seven generations ahead.
The Menominee Forest, which covers nearly 220,000 acres, has more than 30 tree species. A genetically diverse forest offers several different habitats for wildlife species, which contributes to greater overall biodiversity. Eagles, hawks, osprey, deer, wolves, and bears all populate the forest. Genetic diversity also helps ensure a forest’s long-term survival, especially in a time of climate change. Certain tree species tolerate changing conditions better than others. For a community like the Menominee Nation, whose economic interests are tied to timber cut from the forest, it’s important not to rely entirely on species that may become less productive as temperatures rise and precipitation patterns change.
Climate change brings with it additional threats to forest health that its managers must address. Insects and diseases are often among the first indicators of climate change. Higher summer temperatures extend the growing season, giving insects and diseases a greater opportunity to spread. While extremely cold temperatures can kill most insects, this has occurred less and less often over the past 50 years during northeast Wisconsin winters. Thus, insect populations can be expected to thrive. The most dangerous types of insects—invasive species—are those introduced from other parts of the world. With no natural predators in their new forest environments, they grow and reproduce quickly.
Invasive species complicate the Menominee’s goal of preserving forest health for future generations. They further illustrate the importance of maintaining a healthy and diverse forest, as a forest overly populated with one species can be wiped out by insect infestation and any diseases the insects might cause. Beech bark disease causes significant mortality and defect in American beech. The disease is caused by a soft-bodied scale insect that secretes a white wax that may eventually cover the entire trunk. The insect’s feeding weakens the tree, making it susceptible to even more serious damage caused by the invasion of a fungus called Nectria. Another invasive pest discovered in Wisconsin forests is a species of beetle called the emerald ash borer (EAB). While adult beetles feed on ash tree leaves, the larvae do the real damage. These immature beetles feed on the inner bark of the trees, which disrupts the trees’ ability to transport water and nutrients. EAB has killed tens of millions of ash trees in the states it has affected since 2002.