The main differences between vertical Christmas trees and horizontal Christmas trees are:

The valve of the vertical Christmas tree is placed vertically at the top of the tubing hanger, and the horizontal valve of the horizontal Christmas tree is at the outlet tubing.

Vertical Christmas tree downward drilling is done by water pressure or voltage from the bottom of the Christmas tree to the top of the tubing hanger, while horizontal Christmas tree downward drilling is through the radial penetrator next to the tubing hanger.

The tubing and tubing hanger of the vertical Christmas tree are installed before the tree, while the tubing and hanger of the horizontal Christmas tree are installed after the tree.