by John Brouwer
Butternut is related to black walnut. The tree looks like walnut but is smaller and relatively short-lived - around 75 to 100 years. In some regions it is called white walnut.
Similar to walnut, butternut seed is encased in a green husk. However the walnut husk is spherical whereas the butternut is elliptical.
Butternut is native to southern Ontario, Quebec, New Brunswick and throughout the central Carolinian zone in the United States.
Butternut needs sunny sites so it is most often found at the edges of meadows, along fence rows, or filling in openings in the forest.
The nuts are edible and nutritious and are an important food sources of birds, squirrels, and other small mammals. First Nation peoples used the nut oil for cooking, hair dressing, leathermaking, and polishing tools. Cabinet makers and carvers appreciate the wood's softness, colour and texture. It has been an important hardy northern nut tree.
In the forest the butternut was an indicator for wild ginger. Settlers collected butternut for the nutmeats which were used in baking and are the main ingredient for butternut syrup.
But Butternut is quickly disappearing from our woodlands, meadows, and yards. The Butternut Canker fungus Sirococcus clavigignentijuglandacearum is infecting and killing healthy trees of any age and size. This disease is so extensive that butternut is now listed as a Nationally Endangered Species by Environment Canada and designated as an Endangered Species by Ontario.
The fungus enters trees through buds, a wound, or insect openings in the bark. By attacking the cambium layer under the bark, the fungus cuts off the flow of nutrients to branches and stems. In the final stages of the infection a black ooze develops on the infected branches. Gradually branches die and eventually the whole tree can succumb.
The fungus was first discovered in 1967 in the United States. In 1990 it appeared in Canada and has now spread throughout the butternut's range.
At this point there is no known cure for butternut canker so the recommended strategy is to manage existing stands to minimize tree stress. Surrounding trees are cut to eliminate sunlight competition. Seed is collected from healthy trees and planted out to support genetic resistance.
Under the Ontario protection legislation it is illegal to cut or prune a butternut tree without a permit.
There are two butternuts within a kilometre of the co-op. The large spreading tree by the dam pavilion in the conservation area is a butternut. Most co-op children have climbed this tree and perched in its branches. It shows no symptoms of butternut canker.
The other butternut is in the field to the west of Westmount Road and south of Bearinger just beyond the pine trees outlining the old homestead. This is a much smaller tree and does exhibit canker symptoms.
There are now two butternut saplings in the co-op in the field between block 2 and Pine ridge road. Both are 5 years – one has reached 10 feet and the other is around 6 feet.
There are also some saplings growing in the Environmental Reserve in the open area near the power line crossing.
This year I was able to rescue thirty seedlings that had sprouted in the cornfield by the butternut near the old homestead. These are now potted up and in our tree nursery. The tree was very prolific this year and I gathered about 75 nuts which are also planted in the nursery – under wire mesh to keep out the squirrels.
This region is the northernmost range of butternut and as such may have unique genetic material. Butternut needs to be preserved and planting seedlings from local trees may preserve the strains which, having the ability to withstand severe climatic stress, may also be found to
develop resistance to the canker.