Ask Mr. Smarty Plants

Quercus palustris (pin oak) is native to New York, and is one of the faster-growing of the oak trees, so perhaps your recent efforts helped with the growth spurt. This USDA Plant Profile indicates that it is also native in or near Onondaga County and it is known to be somewhat tolerant of urban conditions. However, any time a plant that has done so well for a number of years in one spot has sudden changes, you have to ask yourself what has been the change in the environment? Because we are neither entomologists nor plant pathologists, we can only suggest links to some websites that might give you some clues, and then some contacts that hopefully will help you diagnose and, if possible, treat the problems. 

First, because the Pin Oak is a red oak, we must mention the dreaded Oak Wilt, to which red oaks are most susceptible. This has long been a big problem in Texas, but to our surprise, it has cropped up in New York. Read this article from Cornell University Plant Clinic: "Oak wilt - a new threat to forest and landscape trees in New York State." The bark of this tree is thin and easily damaged, and the nitulidid beetle, which spreads the oak wilt fungus, is always happy to find a split or opening in the tree's defensive bark. Another possibility for the bark damage is canker (Cornell University Plant Disease Diagnostic Clinic).  We don't have a clue to the "flying ants" near the tree. Termites, perhaps?

At any rate, it's obvious you need more help than we can give you, so we are going to refer you to Cornell Cooperative Extension - Gardening. Click on the "Get local help" link and you will get contact information for people who know a whole lot more about the plants, pests and diseases of New York than we do. This site mentioned that some of the county websites were not up yet, and we found this to be the case with Onondaga County; however, there are telephone numbers at the bottom of that page.

Quercus palustris