The term SCOT ALDER TREE can be broken down into three parts: SCOT, ALDER, and TREE. The first part, SCOT, is an acronym for the Scottish National Tree, which is a species of tree native to Scotland. The second part, ALDER, refers to a type of tree in the birch family that is found throughout Europe, North America, and parts of Asia. The third part, TREE, is a general term for a woody perennial plant. The crossword solution for this term is ARN, which stands for Alnus, the genus of ALDER trees.