· Brent Wilson's Answer
· Hi Ninad,
If they are Kwansan Cherry, these are highly susceptible to bark splitting, as are other flowering fruit trees and thin barked trees. The split probably occurred when the tree was much younger and has been in the healing process since. Bark splits are not likely to be fatal to trees, though it does expose a tree to other outside threats like insects and disease which can enter and cause more damage through the split. Through proper treatment to encourage the natural callusing process, a tree should be able to close most splits. Yours seems to have healed quite well on its own and infection from outside sources probably won't be a problem.
There's several things that can cause the splitting. Newly-planted trees or young trees are more prone to bark-splitting. The split was probably caused from severe and rapid weather change; whether it went from hot to cold or cold to hot very quickly. These changes can cause small cracks which then can grow into larger openings over time. Long dry periods followed by very wet weather can also cause bark splitting.
There's not much you can do now except to allow the tree to continue healing itself. Wound paint or sealers won't be of much help. You can fertilize the trees but make sure not to do so too late towards winter as this can cause problems. Cease any fertilization two months or so prior to the first frost date in your area.
Had you been able to catch the split early you could have done some tracing around the wound. If any new splits show up you can follow these instructions for tracing:
With a sharp knife, starting from one end of the split, trace around one side of the wound, about 1/2 to 1 inch back from the split bark. Stop at the other end and do the same procedure on the opposite side of the split. Knives should be sterilized between cuts by dipping for several minutes in a 1:10, bleach/water solution or a 70% alcohol solution to avoid contaminating the cuts. Carefully remove the bark from inside the traced area. You should now have a bare area. Remember to leave this untreated. A tree growing with good vigor usually calluses over quickest. Encourage vigor in the tree with yearly spring fertilizer applications and be sure to provide adequate irrigation in hot, dry weather. Bark splits will often close over completely, leaving a slight ridge in the trunk where callus tissue has been produced.
Hope this info helped. Best of luck with this tree.