One of my sweet gum trees has begun seeping sap from the main trunk, a few...
One of my sweet gum trees has begun seeping sap from the main trunk, a few feet off the ground. I see no other visible sign of infestation, and the tree seems otherwise healthy, but the affected region spreads halfway around the tree and extends a few feet vertically, and is growing. Is this most likely due to disease? canker? insect? And can anything be done to save the tree? Nearby trees are ok (sweet gum and otherwise), but a couple years ago neighboring willow trees a few feet away died (I assume that's a coincidence, as they had visible infect infestation). The tree in question now does have an old 'injury' from where a hammock was attached years ago; the hammock is long gone but a small metal hook is still embedded (swallowed up as the tree matured). It seems unlikely the embedded metal would be directly causing damage at this late date, but I suppose it could always serve as an entry point for infestation; it is about a foot or two above where the bark is seeping.
Your sweet gum tree may have slime flux, a harmless bacterial infection. The infection doesn't hurt the tree, but the tree still tries to expel it by flooding the area with sap flow, which looks messy. Here is some more information about it from our website's Plant Diagnostic: http://plantdiagnostics.umd.edu/level3.cfm?causeID=1230
It is also possible that there is a rot resulting from the hammock hook. But in that case, the bark would probably be loose or cracking, that would indicate a more serious problem than slime flux. There is a good chance there is no connection. Get back to us if you start seeing more symptoms.