When damage is occurring at the leaf margin like this, the problem is probably related to root conditions and the ability of the plant to take up nutrients or to a fungal disease like verticillium wilt.

The dramatic rains that we have had this spring have left many plants in soil that no longer drains as quickly as is healthy for the plant; sometimes trees can sit in a pool of water for days. That situation affects the tree at the roots and causes it to be unable to take up water and nutrition efficiently, which can lead to browning, particularly at the branch tips. There could also be a problem with the pH of the soil, though red maples are reasonably tolerant of alkaline soil conditions.

The other issue that is everywhere in our state this spring is fungal disease. It is nurtured and transmitted from leaf to leaf by water so infections that might have been minor are spreading with every rain shower and prospering in the damp left behind. Verticillium wilt is a serious fungal disease that may come from the soil or even wood chips used to mulch a garden. It is hard to identify because the symptoms are varied but brown leaf margins are among them.

The diagnosis of verticillium wilt requires lab culture. It would be best, however, to begin with an examination by a certified arborist who can assess the conditions of the tree's position and the soil, and look for any undetected issues on the trunk (woodpecker or animal disturbances, mechanical damage, insects) and branches. You can find a certified arborist in your area through the International Society of Arboriculture (www.isa.org).

If you are interested in submitting plant materials to a local lab for diagnosis, you can contact the nearest Cornell Cooperative Extension Office for instructions on how to submit a sample to their labs.  The Nassau County Office is probably closest to you. (http://ccenassau.org/gardening/help-for-gardeners)