80+ year old Japanese laceleaf maple with root collar disease (caused by top loading soil during relandscape) affecting about 25-40% of base circumference. Hollow sound, soft, crumbling bark from 1/2" to 1 1/2" deep, towards center. No insects observed within rotted bark. Some areas of callous forming. Dieback in upper crown, symptoms affecting one major branch. We plan to remove top loaded soil a minimum of 2' out from around trunk, to level of flares. Soil samples being analyzed for fertilization needs. In removing soil on 1 side, fine hairlike red rootlets found at surface above flares. 1. What is safest way to remove dirt without harming roots? Compressed air device or high-pressure water? 2. Where bark and underlying tissues are dry, soft, hollow, and/or breaking off, shall all this be removed, albeit carefully? If wet? 3. If fertilization is needed, what is appropriate method? 4. Do JM have flares around entire circumference? See photos. Thanks.
Yes Yes, from the trunk. No!!! I have not experienced your situation with maples but I have seen it with mature oaks, invariably the tree, sooner or later, dies. Mature trees are generally far more delicate than adaptable younger trees. The rotten part of the trunk will very likely be the point of entry of other pathogens that will weaken the tree even further. The best you can do is to insure that the tree gets adequate watering and is not lacking any nutrients in order to try to prolong your enjoyment as much as possible. Gomero
Thanks for your reply. I've since learned the problem appears to be root collar disease, caused by root collar area being buried during landscaping renovation. the treatment is to excavate the root collar and provide a retaining wall to prevent further soil contact with the root collar, to fertilize as you suggested and provide adequate water. As for removing dead bark, as you suggested, I've not found any resource info about how to do this, nor how extensive this removal should be. Any details on this are welcome.
You want to remove any dead bark that is loose and comes off easily using your fingers or a cutting tool, you do not want to damage the healthy bark. By looking to the new pictures, one concern that I may have relates to water pockets: you should monitor your tree during the rainy season to assess if water is being retained in the holes that have appeared in the bark after the removal of the rotten bark. If that is the case you should act to provide drainage (like by cutting the retaining piece of bark), otherwise the rot will certainly accelerate in those areas. Gomero
