Officials for Pictured Rocks National Lakeshore in Michigan’s Upper Peninsula said an advancing beech bark disease that has spread across the northeastern United States is now moving quickly across the park, leaving dead and dying beech trees in its wake.
The Mining Journal reported that the disease, which includes insect and fungal components, produced its first visible symptoms at Pictured Rocks in 2001 and is expected to eventually claim thousands of trees at the park.
Bruce Leutscher, chief of science and natural resources at Pictured Rocks, said that in the years since first discovery of the symptoms at the national lakeshore, park rangers have been monitoring the progression of the advancing front of the beech bark disease, as well as removing trees presenting falling hazards near park facilities, picnic areas, parking lots and other areas.
“The killing front is now quickly spreading from east to west through Pictured Rocks, resulting in a high mortality rate for beech trees,” Leutscher said. “With no intervention, this exotic disease complex may functionally remove an important native tree species which is an integral part of the northern hardwood forest type at Pictured Rocks.”
The pattern of spread of the beech bark scale insect, followed by occurrence of fungal infection and later tree death, led to a classification in 1972 of the beech bark disease development that is still used today.
Leutscher said the “advancing front” is found in areas recently invaded by beech scale insect, characterized by forests with many large, old trees supporting scattered, sparse building populations of beech scale.
This is followed by the “killing front,” where areas are characterized by high populations of beech scale, severe fungal attacks and heavy tree mortality. This is the condition now wildly spreading across Pictured Rocks.