One of my clients has several huge sweet gum trees in there front yard with a trunk diameter of around 4ft. All but 2 of them look great and healthy.. One is dead completely... The other in question is alive but it's bark is almost falling off at the trunk and 6 ft up. It has small bore holes all in it.. Pull the bark back where it's rotted and there r ants everywhere.... There is limbs beginning to die on this tree but most is still green at the moment. Could ants b the cause of this or they the secondary problem? I notice the dead tree has fungus at the very base of the tree where it meets the grass. The lawn has irrigation and I noticed with this tree that's I'm concerned about its like there is sawdust at the base. Not much but some.. Any help would be great thanks!