Betula

Betula is a genus of deciduous trees and shrubs in the family Betulaceae, comprising about 30 to 60 species depending on the circumscription used. Commonly known as birch, these plants are native to the temperate regions of the Northern Hemisphere, with populations across Europe, Asia, and North America. They are frequent in moist woodlands and along rivers, and several species are cultivated as ornamentals.

Most birches have slender trunks and characteristic peeling bark that is white, gray, or yellow. Leaves are simple, alternate, and serrated. In spring they produce small catkins, typically dioecious, followed by winged seeds.

Notable species include Betula pendula (silver birch) and Betula pubescens (downy birch) in Europe; Betula nigra (river birch) in the southeastern United States; Betula lenta (sweet birch) and Betula alleghaniensis (yellow birch) in North America. Taxonomic placement varies among authorities, with some recognizing different species or subspecies within a broad Betula complex.

Birches are often early-successional, colonizing disturbed sites. They form ectomycorrhizal associations, contributing to soil connectivity. They prefer moist, well-drained soils but are generally hardy and adaptable. Some species are susceptible to pests such as the bronze birch borer in North America.

Wood is valued for furniture, plywood, and veneer; bark was used historically for canoes and containers; sap can be tapped in spring to make birch syrup or beverages. In culture, birch has symbolic meanings in several regions and features in various traditional crafts.