Stalk

The Stalk is the only known way to travel up the World Tree, but it is not known how this is possible. Merchants use this to trade and move good up to the other floors and climbers use it to travel up to the top.

About
Little is know about how this method of transportation works as it is like a beam of light that instantly transports anything it touches up to the next floor. This method the stalk uses can only be used to travel to the next floor up and you cannot skip and floors, it can also not be used to go down as the only way you descent the tree is to fail a test and be transported to a waypoint.

Uses of the Stalk
As the only known way to descend the World Tree is to fail the exams, climbers have no way of getting items or materials from floors below themselves and this is where the merchants and traders take advantage of this system. Many merchants and traders will set up shop on a floor and will trade with the climbers who come up from the last floor or who have failed exams and have items and materials from the floors above.

With this system it is much better to set up shop on the 1st floors of each new 10 floors as the traders will get a chance to trade with the climbers who have just finished a final ranking exam (much better items and materials than normal floor exams) and the the first chance to trade with failed climbers who have come down from higher floors.