Chestnut  Oak (Quercus montana)  forests only grow at the highest elevations in Lewisboro at Mountain Lakes camp, Ward Pound Ridge Reservation and a few other locations. They thrive in dry, very thin, rocky, acidic soil on hilltops. The very thick bark of the chestnut oaks makes them fire-resistant so that when lightning strikes hilltops, chestnut oaks survive, while other competing vegetation does not.

The chestnut oak is easy to identify based on its massively ridged dark gray-brown bark, which is the thickest of any oak in North America!

Other plants growing along side chestnut oaks in these harsher environments include the black oak, mountain laurel, huckleberry and blueberry with Pennsylvania sedge and pin cushion moss making up the groundcover.