'forest-related' is a compound formed from the noun 'forest' and the adjective 'related'. 'forest' originates from Old French, specifically the word 'forest' (from Medieval Latin 'foresta'), where the element meant 'woodland' or 'forest'. 'related' originates from Latin, specifically the past participle 'relatus' (from 'referre'), where the prefix 're-' meant 'again' (or 'back') and 'ferre' meant 'to carry'.

'forest' entered English via Old French 'forest' (Medieval Latin 'foresta') and became Middle English 'forest'. 'related' came into English via Old French/Anglo-Norman forms of the Latin root and Middle English 'relaten/related', ultimately producing the modern adjective 'related'. The compound 'forest-related' is a modern English formation combining these elements to mean 'connected with forests'.

Initially, 'forest' referred simply to a woodland area and 'related' carried senses of 'brought back' or 'connected (by relation or narrative)'. Over time, 'related' developed the sense 'connected with' or 'pertaining to', and the compound came to mean 'pertaining to forests' in contemporary usage.