Not only good things can be said of the butternut tree and it would be wrong to avoid mentioning the deleterious effect that a butternut tree may have on other trees planted within the radius of its root system.  I have had several experiences of this kind.  One butternut tree on my farm, having a trunk six inches in diameter, killed every Mugho pine within the radius of its root system.  This amounted to between 50 and 100 pines.  Their death could not be attributed to the shade cast by the butternut as Mugho pines are very tolerant of shade.  As the first branches of the butternut were more than three feet off the ground, the pines could not have been influenced by the top system of the tree nor do I believe that it was due to fallen leaves, but rather directly to the greatly ramified roots.  Large evergreens, such as Colorado blue spruce, native white pine, limber pine and Jeffrey pine are known to have been similarly influenced.  While small butternut trees do not, in my experience, have this effect, this may be explained by the fact that the radius of their root systems is much more limited.  Most plants, other than pines, thrive within the influence of butternut roots, however, and it certainly does not damage pasture grass as some of the country’s best grazing land is among such trees.  The damage results from a chemical known as Juglone which is elaborated by the root system and when the roots of the butternut cross those of its evergreen neighbor, this acts as a poison to the evergreen and may kill it.

[Illustration:  An 8-foot propeller of butternut wood is the prime mover for wind power generator which in a brisk wind generated 110 volts and 10 amperes at 300 RPM.]

The butternut is attacked by one serious disease which is in the nature of a blight (melanconium oblongum), since it is transmitted through spores.  It usually attacks old trees, the branches of the top part dying, and the bark on the main trunk becoming loose.  The disease progresses slowly and I have seen large trees infected for twelve or fifteen years, continuing to bear fine crops.  It does have a very weakening effect, though, and eventually saps the life from the tree long before its natural span of life of about fifty years is over.

Chapter 9

PIONEERING WITH ENGLISH WALNUTS IN WISCONSIN

The convention of the Northern Nut Growers’ Association at Geneva, New York, in 1936, brought many interesting subjects to the attention of nut enthusiasts.  None, however, commanded as much attention as an exhibit by Paul C. Crath, of Toronto, of walnuts from the Carpathian Mountains in Europe.  There were more than forty varieties of walnuts represented in it, in sizes ranging from that of a large filbert to that of a very large hen’s egg, and in shape being globular, ovate or rectangular.  The exhibitor had these identified by varietal numbers until testing and propagation should suggest appropriate names.