How to help trees survive after flood

Trees are among the victims of the flood of 2017.

And you may not really know it for a while, according to arborist Shawn Kingzette, district manager for Davey Tree Service in East Dundee.

Having its roots submerged for more than a week can kill a tree's root cells. Roots need oxygen, and water-filled soil doesn't let oxygen in. Having surface roots exposed and bark covered in silt doesn't help either, nor does being gouged by floating debris.

The tree may not die or fall over this year.

"It's more of a gradual thing," Kingzette said.

Particularly vulnerable are upland trees, such as oaks, hickories, lindens and some maples, he said. They aren't designed for standing in water.

"In our area, oaks are already 100 to 150 years old and not used to being in extra-wet conditions," he said.

Damaged trees are attractive to pests, such as the twolined chestnut borer. It feeds on struggling oaks from the top down and can take two to three years to kill the tree.

"Stressed trees actually do put out scents and indicators that say (to pests), 'Hey, I'm struggling,'" Kingzette said.

Besides the obvious broken limbs, exposed roots, gouges in the trunk, tree owners will want to keep an eye out for premature fall color, as well as wilted leaves, discolored foliage and dieback, which is when a leaf of root dies from the tip backward.

As for how to help, trees that are unstable or leaning may be reset or staked. Sediment should be removed from around trees as much as possible to return the soil level to the original grade. Consider calling a tree service to aerate compacted soil.

And lay down some organic mulch around the tree, such as wood chips or chopped leaves. The mulch will decompose, rebuilding soil and protecting new, sensitive root cells. Just don't let the mulch touch the bark.

Add mulch to protect new, sensitive roots.