I was reading the June/July 2019 Minnesota Forestry Association Woodlands bulletin. There was an article on “The Endangered Trees of Minnesota”. Two species – Butternut and Eastern Hemlock are considered endangered, meaning that they are vulnerable to extinction. Per the article Butternut is a medium to large hardwood tree with pinnately compound leaves and thick, ridged gray-brown bark. The butternut canker came onto the American scene in 1967. It was first reported in Wisconsin. The butternut canker is a fungal disease that is almost always fatal to butternuts. The fungus attacks the tree’s cambium and leaves a dark canker which eventually girdles the tree.
Over the years I have known about dying Butternuts. I even recall dead Butternuts in the woods I grew up in during the late 70’s and 80’s. Soon after we bought our acreage in 1992 I discovered a very large 80% dead Butternut. I have kept an eye on it and it is still standing but has very little live growth. Then in 2015 while walking down a trail on the bottom-land which had a number of black walnuts I noticed a tree which didn’t quite fit in.
Butternuts and Walnuts are closely related. I looked closer at this tree and it had what looked like small cankers which Walnuts don’t have. Since I have seen Butternuts before I thought this could be one. However it was very healthy, just a few dead branches. The only way to be sure was to see the nuts. I got out a long zoom camera and took pictures of the nuts way up in the canopy. I then sent them to a Butternut expert in Rochester and he confirmed it was a Butternut. He even came out to our woods and had a look at it. The nuts are oval and have a sticky outer green husk as you can see below.
A relatively healthy Butternut which has fought against the fungus and is winning is important to saving the Butternut species. Each year I collect the nuts and am trying to grow young healthy Butternuts. I have found that growing Butternuts is much tougher than growing Walnuts. All our family knows the location of “The Butternut” and they make fun of my extreme interest in it. But because it is so unique we will continue to call it “The Butternut”