Abstract: A saddle tree including a progressive flex headplate, and a saddle constructed therewith, which are capable for properly fitting a variety of different size horses. The headplate assembly is constructed of a plurality of flexible, and resilient overlapping layers which increase in length from top to bottom and which are secured together at the center point of the layers. The configuration supplies the headplate assembly with non-linear resistance, permitting progressive flexure of the legs of the headplate assembly while providing resistance in response to flexure of each leg, providing the headplate assembly with points that flex to properly fit horse's horses of varying widths.