1765-75, Americanism; earlier hackmetack woods, hakmantak dense forest or interwoven shrubbery of tamarack or other conifers; probably < Western Abenaki
Examples from the web for hackmatack
Her double-decked hull was constructed of oak and hackmatack.
hackmatack and white oak knees give strength to the hull and to the white pine deck.
hackmatack knees and shelf and clamp give strength and support to the hull and white pine deck.