Singed brown edges on leaves of trees are called scorch. This can be caused by different types of stress such as drought, root growth restriction, compacted soil or even salt damage. Oak Wilt is a disease which also causes browning of the tree leaves. Bacterial Leaf Scorch (BLS) is a disease which infects Oak trees as well as Maples, Lindens, Elms and others, although it is more commonly found in Oaks, especially Red Oaks. Leafhoppers, spittle bugs and other Xylem feeding insects carry the bacteria from tree to tree.