Broken Tree of Saddle
Checking your saddle for a broken, twisted or stretched tree is important. This can occur at any time when least expected. Saddle trees are make from different materials. Some plastic trees are likely to warp under pressure and heat. Below is a picture of a saddle with a warp tree. The horse ridden with this saddle become very sore in the back and hindquarters. Eventually the problem was discovered. With regular massage and rest from a saddle, the horse's back recovered. A saddle that is disrupted through the tree generally has wrinkles in the seat area.
A saddle tree can experience these problems from a fall, horse rearing and bucking. Also if you keep your saddle in the hot sun then ride in it. If you do not sit straight, over time the tree will become twisted.
Hold the cantel on your sterum and then apply pressure towards your sterum. If there is a problem the tree will bend as shown. A spring tree will have some movement but not this much as shown. A broken or warp tree will spread and move as the horse is ridden. It will become worst as the horse warms up and the heat from the horse makes the plastic tree more flexible.
Creases under the panels
A saddle that has wrinkles/creases in the seat or under the panels is a problem. This shows the saddle is obviously moving and flexing.