'tree-shaped' originates from the Old English word 'trēow' for 'tree' combined with the adjective-forming element from 'shape' (from Old English 'gesceap' / 'sceap'), where 'trēow' meant 'tree' and 'shape' meant 'form' or 'appearance'.

'tree-shaped' is a Modern English compound formed by combining 'tree' + the past-participial/adjectival form 'shaped' (from Middle English 'shape', from Old English 'gesceap'), resulting in the descriptive compound now written as 'tree-shaped'.

Initially the parts meant 'tree' and 'form/appearance'; the compound has retained the original combined sense of 'having the form or appearance of a tree' into modern usage.