Abstract: Disclosed is an improved apparatus for engaging and climbing columnar structures such as trees and poles that includes improved structural support members and an improved foot climber assembly. The size and shape of the structural components have been optimized for strength and portability. The improved tree-gripping surfaces have a curved shape, an increased thickness, and a series of substantially parallel ridges along the outer surface for stronger and more stable gripping ability. Softer stops and tighter locks are provided between components for quiet assembly and operation in sensitive habitats. The geometry of the apparatus positions the hunter's weight to maintain a strong and safe tree-gripping lever action in order to prevent the apparatus from slipping down the tree. The flexible seat permits the user to remain safe, comfortable, and motionless for long periods. The user can climb and descend the tree with the assistance of the apparatus.