Eastern Black Walnut and Thousand Cankers Disease

Walnut Tree, Looking Up (Michigan), photo by Philosopher Queen.

Just a little Editor’s note rant to say that I grew up with a simply gorgeous black walnut tree in my yard, and it really upsets me when I have to write about yet another species that I love under threat of destruction by our out-of-control ecology. Some days it feels like all we’ll have left is squirrels, asian carp, emerald ash borers and kudzu. Also, sorry this is so long … I just kept learning stuff.

The Great Lakes Echo has a feature on Thousand Cankers Disease that attacks black walnut trees. The disease is caused by the walnut twig beetle and a newly identified fungus, geosmithia morbida, that act together to destroy walnut trees and is especially deadly to eastern black walnut. Both beetle and fungus prefer warm weather, and the theory is that it could be spreading north because of temperature. It has already been found in Pennsylvania, and Michigan and other states have a quarantine. (we know how well that worked for ash trees though)

Wikipedia’s entry for Juglans nigra aka Eastern Black walnut says that black walnut is a deciduous, flowering tree in the hickory family that is native to eastern North America. It can reach heights over 100 feet, growing tall and straight in the forest or spreading with a large crown in the open. The history of black walnut at the Walnut Council says that:

The tree once grew abundantly in the eastern bottomland forests, where the soil was deep and rich. Trees 150 feet tall with 50-foot clear stems and 6-foot diameters were not uncommon. Black walnut was the number one prized fine hardwood in America at a time before the use of veneers. Early colonists exported the wood to England from Virginia as early as 1610. Solid walnut wood was used in every sort of homemade furniture imaginable, during the Colonial and Federal periods, but rarely was the fine grain appreciated. Most pieces were covered with a coat of paint. The rage for walnut as a fine furniture wood occurred in a period from 1830-1860, during the popularity of the Empire, Victorian, and Revival styles. Unfortunately by this time, black walnut wood was already becoming scarce.

During pioneer times in the Midwest states, black walnut was still very abundant, although the extremely large trees were already gone. The tree was often cut for rudimentary things as split rail fences. Millions of railroad ties were made from walnut, since it resisted rot when in contact with the soil…

Black walnut never faltered in its use as gunstock material. It is unsurpassed, since no other wood has less jar or recoil, it doesn’t warp, shrink or splinter, and it is light in proportion to its strength. The smooth, satiny surface makes it easy to handle. The U.S. Government used black walnut gunstocks for generations and it is still the favored wood for shotguns and rifles used by hunters and sportsmen.

In a 1993 Michigan forest inventory, it was estimated that there are about 8.5 million walnut trees in Michigan’s forests. Mike has a nice detail of walnuts on the tree, Julie has a cool shot of a cardinal in a walnut tree, and you can see a gorgeous photo of a walnut tree in France on Wikipedia that really shows the spread of the tree and is big enough to make a great background! There are also some photos and drawings in the USDA Plant Profile for black walnut. If you have a wheelbarrow full of walnuts, you might want to read about growing & harvesting walnuts or watch this video. And finally, if you’re looking to plant some walnut trees, click that link!

View Cynthia’s photo on black and in her Trees slideshow.