Quebracho

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 has been used as a source of tanning material for nearly 100 years but has been widely used only in the 20th cent.; today it 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.

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quebracho [kā′bra·chō]

(botany)

Any of a number of South American trees in different genera in the order Sapindales, but all being a valuable source of wood, bark, and tannin.

(materials)

A drilling-fluid additive used for thinning or dispersing in order to control viscosity and thixotropy; made from an extract of the quebracho tree and consisting essentially of tannic acid.

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Quebracho 

the name of several subtropical species of South American trees and of their wood, bark, and tanning extracts. The species Schinopsis balansae and S. quebracho-colorado (also known as S. lorentzii) of the family Anacardiaceae have a hard heavy wood containing approximately 20 percent tannins. The bark of Aspidosperma quebracho-bianco of the family Apocynaceae contains alkaloids (the most active, yohimbine) and approximately 25 percent tannins.