Oak Wilt Discovered In Forest County

Oct 9, 2019

Red oak
Credit Pixabay.com Sweetaholic

Add Forest county to those affected by the tree-killing Oak wilt disease.

The DNR tested wood samples taken from two red oak trees in the town of Lincoln, just north of Lake Lucerne.

Oak wilt is common in the southern two-thirds of Wisconsin, but only within the past few years has it been found in the Northwoods. Forest was one of the last area counties without the disease. Iron county has not had a verifiable infestation.

Linda Williams is a DNR forest health specialist in Woodruff...

"...Until now, Forest county had not had any oak wilt positively identified within the county boundary. Some of the counties around it certainly had Oak wilt. Forest county did not, until now. We did identify two trees in the same area that were dying and wilting from oak wilt this year..."

Oak wilt is a fungal disease that kills thousands of red oak trees each year. It plugs the areas in the tree where water moves, slowing the water down and causing the leaves to wilt and fall off. Red oaks have pointed leaves while white oaks have rounded leaves.

Williams says to slow the spread, but careful when you prune oaks...

"...A lot of oak wilt is introduced in the spring when people are out pruning or wounding trees. So if people can avoid pruning, wounding or harvesting oaks during the spring time period. In this area it's April 15-July 15, that can really significantly reduce the risk of trees getting oak wilt...."

Williams says infected trees start to wilt and drop green or partially green leaves in late summer. She says these are not the brown, dry leaves you see in autumn. They fall rapidly from the tree, with a tree losing most of its leaves within a few weeks. She says unlike an infestation of Emerald Ash Borer which can wipe out ash trees, oaks will regenerate in the an affected by oak wilt.

Oak wilt can be transported on fire wood, so she says get firewood locally.