I have a 40' tall Northern Pin Oak that the leaves are being eaten. I would say that 75% of the leaves show some damage to the extent that there is nothing left on some of the leaves but the 'veins'. Wondering if anyone knows what could be causing this, if there is concern about the health, and how I should treat it? My 4 acres are surrounded by Red Pines, this is the only Red Oak around, right in the middle of my yards...a good distance to any other tree. I did plant a Bur oak from acorn a few years ago, about 3' tall now and only a couple leaves shows damage.

Every spring for one evening, thousands of beetle swarm around this tree but there never seems to be any damage the next morning.

Thanks,

Lee