Varnish tree

Article By:

Strausbaugh, Perry D. Department of Botany, West Virginia University, Morgantown, West Virginia.

Core, Earl L. Department of Biology, West Virginia University, Morgantown, West Virginia.

Last reviewed:January 2020

DOI:https://doi.org/10.1036/1097-8542.728300

The deciduous plant Toxicodendron vernicifluum (previously known as Rhus vernicifera), also called lacquer tree, a member of the sumac family (Anacardiaceae). The varnish tree, which can reach a height of 40–60 ft (12–18 m), is a native of China, but it has long been cultivated in Japan (where it is called the urushi tree). When the bark is cut (see illustration), it exudes a milky juice (sap) that darkens and thickens on exposure. This exudate, which can cause skin irritation, has been used as a lacquer in China and Japan for thousands of years. When properly applied, the thin transparent film becomes a varnish of extreme hardness. Lacquer is a remarkably protective coating because it is not altered by acids, alkalies, alcohol, or heat up to 160°F (71°C). Nutgalls (nut-shaped galls, which are a source of tannic acid), iron in solution, and gold or other metals are mixed with the exudate before drying to make the various kinds of lacquers. The process of lacquering is technical and tedious; in some cases, 300–400 coats are required, and it may take several years to complete the finish of one item. See also: Lacquer; Sapindales; Varnish

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