Sometimes, when bark falls from tree trunks, we can see that the wood is twisted. The grain corkscrews upward in patterns that have been mysterious to me. In response to an inquiry, a little web research reveals a possible explanation. Branches and foliage grow more luxuriantly on the sunny side of the tree. That's the south side around here. Prevailing wind in this area is mostly west to east. That creates more pressure against the south side of the trees, gradually twisting them as they grow. Or at least that's the best story to stick to that I could find. Other possibilities mostly included bugs. These trees are bristlecone pines in Mt. Evans National Park. The larger ones are more than a thousand years old. My memory was that at least some were twisted. Now that I look at the image, we can see that my memory may be too old.