National Geographic : 1958 Mar
© National Geographic Society A Short Spike Marks the Heart of the Oldest Known Living Tree This pine has survived more than 4,600 years; missing rings make precise dating difficult. Dr. Schulman calls it a pickaback tree because new growth has mounted the old through the ages. Here he grasps "Great-granddad," the primary stem. "Granddad" (center) shows a 364 hollow. "Dad," the next layer, is dying. Bark-covered "Junior" (right) keeps the tree alive.