We use a treeless saddle instead of the usual English or Western saddle because a saddle is built around an actual piece of wood.  The tree is great for the horses back if jarred a lot or ridden for hours, but a treeless saddle allows a handicapped rider to feel the movement & warmth of the horse - much like a bareback pad.

     Plus the treeless saddle is built like a western saddle (without the horn) giving the rider security & safety.