quebracho (kābrä´chō), name for a tanning substance and for the trees from which it comes, chiefly the red quebracho, or quebracho colorado (Schinopsis lorentzii), of the family Anacardiaceae (sumac family). This hardwood tree, native to the Paraguayan subtropics, supplies one of the most durable and heavy of timbers. It also provides much of the vegetable tannin for the leather industry although the populations are being depleted. The heartwood, stripped of its bark and subjected to extraction processes, is about 30% tannin. Quebracho is obtained chiefly from wild trees of the forests of the Gran Chaco of Argentina, Paraguay, and Bolivia. White quebracho (Aspidosperma quebracho-blanco) of the dogbane family is one of the other hardwoods similarly used and is native to the same region. Red quebracho is classified in the division Magnoliophyta, class Magnoliopsida, order Sapindales, family Anacardiaceae.