What is the wooden frame of a saddle referred to as?

The wooden frame of a saddle is referred to as the tree. This component provides the structure and support for the saddle, ensuring that it maintains its shape and properly distributes the rider's weight across the horse's back. The tree is crucial for the saddle's function and fit, as it affects comfort for both the horse and rider. It is designed to give the saddle its functional and aesthetic shape, with variations in design to suit different riding disciplines and horse conformations.

Other terms in the question refer to different parts of the saddle: the seat is where the rider sits, the flap is the part that hangs down on the side of the saddle and protects the rider's leg, and the gullet is the channel in the tree that runs the length of the saddle, allowing clearance for the horse's spine. Understanding these definitions helps clarify why the tree is specifically the answer in this context.