Karla is standing in a hole made by a pine tree (most likely) several decades ago. Starting as a mere nut, the tree grew really tall, then died and fell to the ground, its roots pulling up a whole lot of dirt and making a really big hole. As time went on, the tree's body slowly disappeared except for a very few pieces and a mound of composted wood and soil. Nice stuff for planting. So the next time you need a big hole and have a few centuries to wait for it to be dug, plant a pine nut.