Alder or Elder is a term used to refer to two different species of trees. Alder is a genus of flowering plants in the birch family, while Elder is a genus of shrubs and small trees in the honeysuckle family. Both species are native to temperate regions of the Northern Hemisphere and are often found growing near water sources. They are both valued for their wood, which is used for a variety of purposes, including furniture, construction, and fuel.