'tree-lined' originates from Modern English, a compound of 'tree' + 'lined' (the past participle of the verb 'line', meaning to form a line or border).

'tree' comes from Old English 'trēow' (tree), which became Middle English 'tre(e)' and then Modern English 'tree'; 'line' as a verb/past participle derives ultimately from Latin 'linea' (via Old French 'ligne'), giving Middle English 'line' and the past participle form 'lined', combined in Modern English as the compound adjective 'tree-lined'.

Initially it described something literally 'bordered or marked by lines of trees' and it has largely retained that literal meaning into modern usage.