larch, any tree of the genus Larix, conifers of the family Pinaceae (pine family), which are unusual in that they are not evergreen. The various species are widely distributed in the Northern Hemisphere. Needles of the larches are mostly borne in characteristic radiating clusters. A western American larch ( L. occidentalis ) achieves a great height, and its lumber is used for interior construction, ties, posts, and cabinetmaking. The American, or black, larch ( L. laricina ), commonly called also tamarack and hackmatack, ranges from the Arctic Circle to cold swamps in more temperate regions of the NE United States and is cultivated elsewhere for its beauty. The wood of this species has been used in shipbuilding and for posts, ties, and poles. The European larch ( L. decidua ) has long been valued for its durable wood and as a source of Venice turpentine. This tree, the Japanese larch ( L. leptolepis ), and the Siberian larch ( L. sibirica ) are also cultivated for ornament. The related golden larch is Pseudolarix amabilis. Larch is classified in the division Pinophyta, class Pinopsida, order Coniferales, family Pinaceae.