We have 3 mature trees on the side of our house that we had assumed for the last 5 or so years had been increasingly dripping "sap". Now it appears that the culprit may be the white substance showing up all over smaller tree branches that looks similar to melted globs of marshmallows. We also have visible green mold on one of the trees, and another had large strips of bark missing higher up. I have attached several pictures. We are trying to determine if these are treatable (and if so, how to proceed), or if we need to remove them all. This would leave very little shade in our yard and the neighbor's, as it is on the property line. Any help would be greatly appreciated.