Twisted trees are cool to see while on the hiking trail. What causes these trees to spiral? Referred to as SPIRAL GRAIN, there is no definitive explanation. It is speculated to be caused by various things. A tree growing in a lop-sided way, which can cause nutrient deficiencies in the roots. This could be from growing out of a rock or leaning onto another tree by way of gravity. Stress from wind storms or droughts can be a factor. Trees with asymmetrical crowns in very wind exposed sights may cause the tree to twist. Regardless, they are interesting to see and found in many areas where trees are present.