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COSEWIC assessment and status report on the Butternut in Canada

Special Significance of the Species

There are about 20 species within the genus Juglans (also referred to as walnuts) distributed in North and South America, Europe, Asia and India. Of the 6 species native to North America, only butternut and black walnut occur naturally in Canada (Farrar, 1995), with southern Ontario encompassing the entire Canadian portion of the range of black walnut, and approximately 60% to 70% of all butternut in Canada.

Butternut wood is lightweight, soft, low in strength, and coarse-grained. The wood is valued for interior finishing, cabinetwork and carving. It does not have high economic value in Canada but is valued in the U.S. as a timber species.

The nuts have a delicious buttery flavour and an oil content of up to 60% at peak ripeness (Rupp, 1990). More than 40 butternut cultivars have been described with a few gentoypes exhibiting good nut qualities for commercial production (large size and ease of cracking) (Ostry et al., 2000). Nut growers value butternut as a cold-hardy, nut-producing species. Nuts are especially popular in New England for making maple-butternut candy. Additionally, there are reports that butternut trees were tapped by the pioneers and yielded an excellent syrup (Lauriault, 1989). However, the ratio of sap to syrup is four times higher than that of maple trees (Rupp, 1990). Nuts are also utilized by wildlife as a food source.

A dye can be extracted from the husks and the root bark and a tea can be brewed from the dried outside bark to cure toothaches and dysentery (Lauriault, 1989). Juglone, which is a component of butternut, is antiseptic and herbicidal: some antitumor activity has also been reported. A recent animal study suggests that juglone possesses sedative activity comparable with diazepam (the prescription drug Valium) (Foster and Duke, 2000).