From the Pictured Rocks National Lakeshore website:
Beech Bark Disease has spread throughout the National Lakeshore, resulting in many dead and dying beech trees. Be aware of these trees and the potential for falling branches and trees.
This disease is initiated by a non-native insect accidentally introduced into the United States. Secondary attack by both native and non-native fungi further stresses American beech trees and causes an unusually large number of weakened and dead beech trees. The insect and fungus pose no direct threat to humans. There is no practical control method in large natural forests.
Ben and I saw the devastation caused by this tiny,
invasive insect throughout our hike.
It is amazing how destructive invasive species can be.
In this case it just weakens the tree's defenses so it falls prey to secondary attacks from fungi that would normally
not harm the trees.
Ben and a beech tree under attack
Beautiful, yet deadly
This last tree isn't a beech, but it had a large fungus on it