Dura-Heat River BirchGrown for its beautiful "exfoliating" (peeling) bark AND 'Dura Heat' has been developed to grow smaller than other River Birch AND to have virtually no summer leaf drop! Trees grow quickly, but mature at about half the size of other birch, making them a good choice for spots too small for larger trees. Leaves are smaller, darker green and glossier than other birch It is this glossiness which helps to retain moisture and avoid leaf drop. Leaves turn