Plant Diseases/Splitting Bark on ornamental Maple
This splitting is near the base and covers the south, south-east side of tree mostly (see pic), with initial/minimal signs of splitting on the north side (i can send a pic if needed). I noticed it last year, and i cant tell if its improving. Its on a hill in the front yard so its not soaked below the waterline. The second pic i included is of the overall tree and you can see its full and healthy. I see no signs of anything on the leaves. Only some ants crawling up the trunk.
Your photos represent damage done to the bark. These splits may be mechanical or weather related. On thin barked trees such as many maples, frost/heat cracks can develope as a result of weather stresses. The splits/cracks can be entry points for insects and/or disease organisms. Some cultivars are more resistant to the weather related splits. I cannot tell if these areas are weather or mechanically related. For the mechanical type splits, or wounds usually some sort of physical damage occurred. Lawnmowers/string trimmers and support straps/ropes are often the culprit. Anything that rubbed or hit the bark previously can cause these. If decay or insects get started in these areas or even a loss of bark tissue, this will weaken the tree structurally, making it easier to break over during high winds or winter precipitation that accumulates on the tree. Unfortunately, this is often a terminal situation. Replacement may ultimately become a viable option.