Sleeping Bear Dunes National Lakeshore - Pests (U.S. National Park Service)

There are a whole host of insects and pathogens (fungi, molds, diseases) that feed on and complete their life cycles within the many different tree species found within the northern hardwood and conifer forests of the Lakeshore. Many of these are pests that are a natural feature of the maturing forests and changing landscapes. On occasion, these pests will reach numbers where they impact and even kill many of a tree species from large blocks of lands. Some of the pine and larch pests do this on a 20 to 100 year cycle. Deaths of oaks from oak wilt seems to be on the rise in the region. Changes in management are warranted to protect the trees from being damaged by human activities and equipment. The birch trees throughout the Lakeshore are succumbing to a number of fungi and diseases. Much of this appears to be part of the natural succession of a hardwood forest as these early successional trees are overgrown and shaded out by maple and beech trees, but the bronze head birch borer have also caused their decline.

Of greater concern are a whole array of non-native pests and pathogens that may soon have devastating impacts on the forests throughout the eastern U.S. Gypsy moths have been a threat to, and, a heavy defoliator of the forests in the East and Midwest for many years. Treatments are now available, but some of these treatments can also be hard on the native moths, so they are only used when gypsy moth populations reach specified levels that could cause high tree mortality. Emerald ash borer insects are moving northward as hitchhikers on firewood. They have been found within a few miles of the Lakeshore. Once established, they can kill all of the ash trees in a forest and there are few viable treatments. Beech bark disease is a non-native fungus that is carried by native insects as they feed on beech trees. It soon kills the host tree and eventually over 90% of the surrounding beech trees. Hemlock wooly adelgid is an insect that feeds on hemlock needles and soon weakens the tree so that it dies. The loss of tree species to this array of pests could completely change the landscape of Sleeping Bear Dunes. Monitoring and action plans are being developed to address these and a host of other threats to the forests of the region. Many new pests are on the horizon as they hitchhike over on crates and packing material from other countries and set-up home in the forests of the United States.