Hi, We have 2 trees that are exhibiting the same symptoms (see pictures), and I am trying to diagnose it and figure out if it is something I need to address so we don't lose the trees. Both trees were planted about 2 years ago. The trees are a Japanese Katsura and Japanese maple. Thanks,
The trees look like they have trunk/bark damage and the damage looks old. Reasons include planting too deeply, cankers, excessive mulch, mechanical damage, drought stress, etc. See our publication on these types of problems http://extension.umd.edu/sites/default/files/_images/programs/hgic/Publications/HG86%20Common%20Abio...
The tree on the left looks like it has been planted too deeply. You should be able to see the flare at the base of the trunk where it joins the root system. You can remove the soil from the circumference of the trunk to the point where the trunk flares out into root growth. Make sure mulch is no thicker than several inches and away from the base of the trunk. We also noticed some lady bird beetles (beneficial ) on the trunk. No control is necessary.
These trees will continue to limp along. All you can do is keep watered during dry periods. No chemical control is recommended.