Is this black walnut dying?
The dying branches and large crack in the main trunk indicate that the tree is structurally unstable and otherwise under stress. We believe it's prudent to ask a forester or certified arborist to assess the tree's health and suggest a course of action.
So far thousand cankers disease has not been detected in Minnesota. A forester or certified arborist is qualified to identify or rule out the presence of this disease.
Go to the following websites to learn more about it: