Keep an eye out for healthy butternut trees. Pessimism about the future of this species is spreading as a relatively new fungus continues to kill butternut throughout its range. Butternut canker (Sirococcus clavigignentijuglandacearum) was first reported in Wisconsin in 1967 and was named and described in 1979. It's origin is unknown. Ninety-one percent of Wisconsin butternuts of all ages are reported to be infected.
The best hope that researchers have is that disease-resistant trees can be found and propagated. To preserve the gene pool, guidelines for cutting butternut have been established: trees with more than 70% live crown and less that 20% of the trunk or root flares affected by cankers should not be cut. Trees with no cankers on the trunk or root flares should also be retained if they have more than 50% live crown.
If you know of a healthy butternut that is within 100 feet of infected butternuts, contact Brent Teillon, the Chief of Forest Protection, at 802-241-3678. Trees that appear to have overgrown or inhibited the growth of cankers are also of interest, but backyard trees which may not have been exposed to the fungus don't qualify as "resistant" specimens. If potentially resistant trees are found in Vermont, the Department of Forests, Parks and Recreation will cut scions (young shoots) next February and send them to Minnesota where they will be grafted onto rootstocks and inoculated with the fungus.
Butternut never occurs in pure stands and is rarely abundant. The trees need fairly large openings when they are young and their crowns must be in full sun. The nuts are important as a food source for squirrels which, in turn, are the bread and potatoes of fox, coyote, fisher and bobcat. It grows farther north than black walnut and is particularly important in Vermont where black walnut is restricted to a small corner of Addison County.