Brown edged leaves on hornbeam

The Carpinus, or hornbeam, is most commonly found in the mild or cooler climates of China, Europe, and the Eastern United States. Possible reasons for brown edge could be drought, excessive heat, lack of proper nutrients, or diseas. I would recommend taking a leaf sample in to your local college to get an answer from their science department. Either that or take a leaf and soil sample to your local courthouse and consult the environmental department.