Q. Seems as if our smaller trees had bark-splitting issues this year. What can I do to prevent this from occurring next year?
A. It is true that we saw a lot of bark damage in young maples and other thin barked species this season.
The most common cause of bark splitting is winter sun scald. Sun scald occurs when the winter sun warms the bark on the west or southwest side of the tree, while the shaded portions of the bark remain cold. This temperature difference between the two sides may cause bark splitting. To help avoid winter sun scald, one can make a hardware cloth cage placed around the bark to break up the sun’s rays. Use 1/4 inch mesh hardware cloth to construct a cage that fits around the trunk from ground level to at least 4 feet. The cage should not directly touch the trunk (keep about 2 to 4 inches away). Moisture and insects can cause issues when vinyl or plastic tree barriers are attached directly to the trunks of trees. Critters can also actually chew through many of these materials. One could also paint the trunk with a white latex paint (low VOC) to reflect the sun’s rays. However, the cage will also protect the trees from vole and rabbit damage.
Splitting can also occur from physical damage. How many times have you accidentally hit the tree with a lawn mower or the weed whacker? Sometimes it only takes a few thwacks to cause damage that shows up later on in the season. Think of the bark as a skin that can be bruised – sometimes repeated thwacking can cause significant cracking. This is one reason why some mulch is good to have around trees to keep the mower and weed whacker away from the trunk.
Bark splitting can also occur when trees are planted too deep, or when mulch and soil is piled up against the trunk. Make sure you can always see the root flare of the tree. Pull away any soil or mulch that may have been indiscriminately piled up against the trunk over time. If the crown area of a tree is too wet, then cracking of the bark can develop from the rotting bark tissue under the gunk. I have seen a lot of this phenomenon this season because of the tremendous amounts of rainfall we received.
Bark splitting can also occur when herbicides are used near trees.
Finally, bark splitting can occur when the tree has an insect or disease issue. If one sees holes in the damaged area, or bark splitting and dead branches farther up in the tree; then submit pictures of the damage to the Extension office at kemeryr@purdue.edu. Usually trees will slowly heal damaged areas.
