spacerspacerIllinois Department of Natural Resources  

March 9, 2010  

Removal of Diseased and Damaged Trees Planned at Illini State Park

Part of effort to prevent the spread of disease to other trees at forested site on Illinois River

MARSEILLES, IL – The Illinois Department of Natural Resources this week is beginning the removal of diseased and damaged trees at Illini State Park in an effort to limit the spread of tree diseases at the park.

Removal of diseased and damaged trees will begin this week at the Marsatawa Area of Illini State Park, where the dead trees were discovered during the summer of 2009.  Park site personnel and IDNR foresters found 24 trees of different species were involved, including 16 black oak trees. Branch samples were cut from the oak 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 have oak wilt.  Oak wilt is very infectious and the trees must be removed this winter in order to slow the spread of the disease.

While a tree-removal contractor is in the area removing diseased oaks, other diseased or damaged trees will also be removed.  They include four ash trees lost to ash decline, one sugar maple that died from verticillium wilt, one silver maple that was hollowed-out due to carpenter ants and trunk rot, and one silver maple and one elm that sustained severe storm damage and will not recover. The trees that are not diseased are in a high-use area of the park and present hazards to visitors.
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 Co.