Butternut, also called white walnut

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Settlers in Wisconsin Planting butternuts.
Butternut, also called white walnut and oilnut,
was a large, deciduous tree, one of several North
American members of the Juglandaceae. It was
valued by native Americans and early American
settlers for its rich and flavorful nuts. They
also used the bark for medicines and as a dye.
Butternut wood made excellent furniture. An
extremely cold-tolerant, hard-mast species,
butternut was an important food for wildlife.
Map showing Native range Of butternut.
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Is butternut extinct?
Well, no, probably not yet. Heres a picture of
a butternut tree growing in the Nicolet National
Forest in northern Wisconsin. This tree was the
state champion tree of Wisconsin in 1990. Its
dead now.
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What killed all the butternuts? About 90 of the
butternuts in the U.S. have been killed over the
last 40 years by an exotic fungus Sirrococcus
clavigignenti-juglandacearum. In many parts of
the former range of butternut there are no trees
left.except maybe hybrids.
Cankers on butternut
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What is being done?
Candidate canker-resistant butternut grafted and
growing in a greenhouse and in a clonal orchard,
two types of tree museums for butternut.
Seeds and scion wood of remnant butternuts are
being collected. We want to know if these trees
survived the epidemic because they were unexposed
to the fungus, resistant to the fungus, or
because they werent butternut.
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Are some trees resistant to butternut
canker? Theyre dying to find out!
Inoculations and other tests of candidate mother
trees and their progeny are under way. The amount
of resistance a tree passes on to its progeny is
a measure of the extent to which resistance has a
genetic basis.
Candidate butternut mother tree to be evaluated
for resistance
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Buartnut kernels
Are the resistant trees butternuts?
Some, we dont yet know how many, are hybrids
with Japanese walnut, an exotic widely planted as
a nut tree.
Japanese walnut twig
Japanese walnut (heartnut) crosses with butternut
to make a Buartnut. We use DNA analysis to
separate buartnuts from butternuts.
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Reintroduction What will butternut be?
Scientists and landowners have made the first
steps toward a long-term and comprehensive
program for the conservation and reintroduction
of butternut. A lot remains to be done. Ask what
you can do to help.