Betula populifolia, gray birch, is a small, fast-growing native tree of the northeastern US, easily mistaken for a young paper birch at a glance — its bark is similarly chalky white — but it stays smaller, doesn't peel into papery sheets the way paper birch does, and shows distinctive dark triangular patches beneath each branch. It is a classic early-successional pioneer species, quick to colonize abandoned fields, burned ground, and roadside cuts, and it tolerates poor, dry, sandy soil that would stunt most other trees. Inconspicuous wind-pollinated catkins appear in spring, and the triangular, poplar-like leaves (populifolia means "poplar-leaved") turn yellow in fall.
It is the shortest-lived of the North American birches, typically declining after 30–50 years, and it is highly susceptible to bronze birch borer, especially once past its vigorous youth or under any drought stress — plant it expecting a relatively short but fast-growing life rather than a long-term specimen tree. Its main landscape value is quick screening, naturalizing on difficult sites, or a multi-stem clump for winter bark interest, rather than a shade tree for the long haul.
Fungal leaf spot
Brown or purplish spots on the leaves, often ringed with a yellow halo, that spread and merge in warm, humid, or wet weather; heavily spotted leaves yellow and drop early.
Pick off spotted leaves and clear fallen debris to remove overwintering spores. Improve air circulation by thinning, and water at the base so foliage dries quickly. If it persists, apply a copper- or sulfur-based fungicide at the first sign.