Evenly spaced vertical lines on a column will seem to get closer together as you near the edges of the column. The same is true of cracks in a tree. On either side of the tree you will see closely spaced, narrow vertical cracks. Toward the middle of the tree, the cracks are more widely spaced. Lets apply this to a drawing of a Coastal Redwood. Click on the first image to start a step-by-step sideshow.