Short short story: "Walnut"

He had lived his entire life in this tree, this tree of senior status, on a grassy knoll where he could only see shades of green from the leaves that entombed him. He was surrounded by nuts, most the same age as he, and while he was programmed not to care, he was weary of the view. It had been a good life, and even though he knew falling meant a slow death, drying from the outside in, he was ready for change.