Trees Take Curious Twists
Ten years ago in this same column, Hans Nielsen made the observation that cracks in dead spruce trees near his house always seemed to spiral down in one direction. That direction was clockwise around the tree (regardless of whether you look at the situation from the top down or from the bottom up).
Neil Davis, who edited this column from 1976 through 1981, found in a survey of his own that 68 percent of the dead spruce trees that he looked at also had cracks that spiraled clockwise. A significant number--about 20 percent--just went straight up and down.
That initial article intrigued me, and I have ever since found myself looking at dead spruce trees to see which way the cracks spiraled. In addition, I've expanded the "data base" to include telephone poles, and I've probably stopped on the highway to look at over a thousand by now.
The results? In over three-quarters of the cases, cracks in the poles run from upper right to lower left--clockwise. In most of the other cases, the cracks run straight up and down, or are just too close to call.
The phenomenon seems to be real. Neither the plant biologists nor the lumber yard workers that I've talked to can offer an explanation. Any suggestions?
