First, tree width. Yes, the tree has to be the correct width; the points should lie parallel to the horse's back (as illustrated in the previous post). But in some cases, the tree can be the correct width and still not fit properly, because many other things come into play: tree shape, gullet shape, length of tree points and panel configuration all contribute to how well - or how poorly - a saddle fits. For example, let's say that you have a lean, high-withered Tb like this fellow here:
Here he is in a saddle with the correct tree width, but with the wrong panel configuration (too shallow):
As you can see, the saddle's sitting pommel-high; it will put the rider too far back in the seat and concentrate pressure on the rear half of the saddle rather than distributing weight evenly over the surface of the panels. And though you can't really tell it from the photo, there was also insufficient clearance over the wither, and the rider's weight would have caused the saddle to sit directly on the withers. (NOTE: This is one reason that so many horses with this conformation are labelled as "narrow", because without panel modifications, most saddles with the correct tree width will sit on the wither; hence the need to go to a narrower tree for clearance. This just causes more atrophy in the back and makes the horse even harder to fit properly.)
So what would have to be done to the saddle? The panel would obviouosly need to be thicker in the rear, but it would also need to be modified in front; in this case, a wither gusset:
and a dropped or trapezius panel:
The combination of these two panel options will "fill in the dips" below those big withers and lift the saddle up off the wither. The photo below roughly shows - in green - where the weight bearing surface will be on a "standard" panel; the red lines show the weight bearing area of a saddle with a trapezius panel and wither gusset:
UP NEXT: Channel width and panel contact. Stay tuned!