[IUFRO RG 7.02 FORPATH] Copper causing circular growth?

I received this from a colleague and wondered if anyone had an answer to his question: Dear Professor Schmitz, I am writing at the suggestion of Mary Warner, associate dean of the medical school. Mary and I have been working jointly on a diagnostic medical case project. For many years I have owned a farm on the east bank of the Hudson River just south of the Rip Winkle Bridge. On the steep bank that descends from the farm house to the New York Central railroad tracks, there is a small forest of sumac trees, interspersed with other growth. The sumac trees generally grow straight up, at a rate of 6 to 10 feet per year, with one exception. The exception comes out of the ground and grows in circles. See photo 001, attached. If you will look to the left of the chain saw, you will see a twisted length of copper about three-quarter inches wide. The copper is embedded in the root system of the crooked tree, and cannot be removed by vigorous tugging. When Mary and I looked at these photos last week in her office, we speculated that the DNA of the crooked tree may have mutated and is sending atypical signals to the trees cells. We talked briefly about Wilson's disease in humans, which is due to an excess of copper in the bloodstream. Needless to say, neither of us knows anything about crooked sumac trees. Our current schedule calls for me to return to New Haven at 11 a.m. on Wednesday March 10th. If you expect to be on campus that day, I could bring you a length of the crooked tree. I plan to stay over at the Graduate Club that night, and will therefore be available on March 11th as well. Alternatively, you might like to visit the farm, which is about 2 1/2 hours from Harkness Tower. I would love to have your views on what is causing the crooked tree to grow in circles. Please feel free to discuss this subject with your students. If you search Google Earth for 194 Greendale Road, Hudson, NY, 12534, you will access an aerial view of the farm. The crooked tree is on the bank to the east of the farmhouse/barn at the north end of the farm. To the west of the farm house there is a pinot noir vineyard, while the grapes to the South are largely Chardonnay. I look forward to hearing from you. With best regards, Peter Brengel, Class of 1953 --- On *Fri, 2/26/10, Peter Brengel /&lt;peterbrengel(a)yahoo.com <mailto:peterbrengel@yahoo.com>>/* wrote: From: Peter Brengel &lt;peterbrengel(a)yahoo.com <mailto:peterbrengel@yahoo.com>> Subject: To: "Peter Brengel" &lt;peterbrengel(a)yahoo.com <mailto:peterbrengel@yahoo.com>> Date: Friday, February 26, 2010, 6:16 PM Here is the crooked tree. Oswald Schmitz Oastler Professor of Population and Community Ecology, Yale University School of Forestry and Environmental Studies, 370 Prospect Street, New Haven, CT 06511 Ph (203) 432-5110; FAX (203) 432-3929