Alder or Ash are both types of trees. Alder is a deciduous tree that is native to Europe, North Africa, and parts of Asia. It is often found near water and is used for its wood and bark. Ash is a deciduous tree that is native to North America, Europe, and parts of Asia. It is often used for its wood and bark, as well as for medicinal purposes. Both trees are popular for their hardwood and can be used in furniture and other woodworking projects.