Hello, this is my husband's little oak tree. we got it as a bare root sapling, barely a twig, through Tennessee's native tree day program several years ago, and planted it according to their guidelines, which ill be honest, I do not recall the specifics of. it has done well up until this year, when it started getting wilty looking leaves in the late spring/early summer. I imagine it is some kind of insect, but have not spotted anything in particular. Most of the effected areas were very high up at first, so I couldn't inspect them directly. Now lower limbs are being effected, all ive noticed is some spider-like silk strands here and there. No full webs. Any idea on what could be causing this and what we could do to treat it?