Wow, I'm going to assume you mean Bartleby the Grandfather tree in the center of Ravenwood....
Once you have completed all your required assignments in Wizard City, Merle Ambrose will ask you to investigate Krokotopia.
Once you have been given that quest, you can access the Spiral door by entering Bartleby the World Tree. Completing crafting quests or other quests that direct you to Krokotopia will not gain you entrance, you must complete the required storyline quests in Wizard City.
After you’ve completed Krokotopia, you can move on to Marleybone, then MooShu, then Dragonspyre, then Celestia. You can visit Grizzleheim at level 5, but cannot return until level 20.
If you want the prize, you have to build the ladder rung by rung. There are no shortcuts.
