Alder is a type of deciduous tree that belongs to the birch family, Betulaceae. There are several species of alder, including the European alder (Alnus glutinosa) and the red alder (Alnus rubra), among others.
Alders are typically small to medium-sized trees that can grow up to 100 feet tall, but most species typically reach around 30 to 50 feet in height. They are fast-growing and can tolerate a wide range of soils, including wet and swampy conditions.
Alders have distinctive cone-like fruits that are woody and persist on the tree throughout the winter. The leaves are typically oval-shaped and have a serrated edge. The bark of mature trees is dark gray or blackish and rough to the touch.
Alders have several uses, including in construction as a hardwood, for fuel, and for ornamental purposes. They are also important for soil stabilization and erosion control in wetland environments. Additionally, alders play an important role in the ecosystem as they are able to fix nitrogen from the air and enrich the soil.