spacerspacerIllinois Department of Natural Resources

July 13, 2010


Intended to prevent spread of disease to other trees

MARSEILLES, IL – The Illinois Department of Natural Resources (IDNR) today announced that a dozen diseased and damaged trees are being removed at Illini State Park in an effort to limit the spread of tree diseases at the forested site on the Illinois River.

Removal of diseased and damaged trees is planned at the Marsatawa Area of Illini State Park.  Site personnel and IDNR foresters found 12 trees of different species were involved.  Branch samples were cut from the trees and taken to the University of Illinois Plant Clinic for testing.  The lab results were not conclusive for a single pathogen.  However, foresters believe all signs and symptoms suggest that the oak trees involved have oak wilt, a very infectious disease, and suggested that the trees should be removed as soon as possible to slow the spread of the disease.

This summer’s tree removal follows a similar effort in which a number of trees were removed last March at Illini State Park.

The area of Illini State Park where the tree removals are to be done will be closed to the public for safety reasons while the work is ongoing.  The public is asked not to remove any of the wood from the area as that might spread tree diseases.  Many of the oaks are also infected with a secondary pathogen called hypoxylon canker.  This disease can also be spread easily and infect trees that are unhealthy, stressed or declining.

Further steps to prevent the spread of disease will be taken after the trees are removed, such as trenching to cut root grafts between infected and non-infected tree roots.  Foresters indicate it could take several growing seasons to break the disease cycle.

Park users are encouraged to report any large oak trees with leaves turning color,

browning up or dropping during the normal growing season.  Illini State Park features a large oak population that produces important acorn forage for a variety of wildlife and a beautiful wooded setting for users.  Finding the diseased trees early can help stop the spread of this disease to other portions of the park.

The 510-acre Illini State Park is located just south of Marseilles on the Illinois River in LaSalle County.