This was transwikied from http://lifeafterpeople.wikia.com/wiki/Tokyo_Sky_Tree
3 Days After People: The Sky tree plunges into darkness as Tokyo's grid fails.
230 Years after People: The Sky tree's sister, The Tokyo Tower is destroyed and the Sky Tree gets light damage from the top.
500 Years after people: After an earthquake , the support columns crack, leaving the floor to fall. The entire building now collapses in a pancake style.