'arbored' originates from Latin, specifically the word 'arbor', where the root meant 'tree'.

'arbor' passed into Old French/Old English forms such as 'arbre'/'arbor', entered Middle English as 'arbore'/'arbor', and the verb 'to arbor' (and its forms like 'arbored') developed from the noun.

Initially it meant 'tree' (the noun 'arbor'); over time it evolved into verbal and adjectival senses meaning 'provided with trees' or 'sheltered by an arbor'.