The tree is the skeleton of every western saddle. Understanding what trees are made of, how they're constructed, and what their failure modes look like is fundamental to evaluating any saddle you're considering buying used.
Traditional Wood Trees
For most of western saddlery's history, trees were made from wood — traditionally cottonwood, pine, or similar lightweight species. The wood is shaped to form the fork (front), the cantle (back), and the bars that rest on the horse's back. The pieces are joined and then covered in wet rawhide, which shrinks as it dries into an extremely strong, rigid casing.
A properly made rawhide-covered wood tree is among the strongest saddle tree constructions available. Custom saddle makers and high-end production manufacturers still use this method. The main disadvantage is cost — wood-and-rawhide trees require skilled handwork and more material than fiberglass alternatives.
Signs of a Compromised Wood Tree
Wood trees can crack, particularly at the fork (front) or at the bars under repeated lateral stress (roping, jumping). The tree-flex test detects this: any creaking or popping under pressure indicates a crack. Soft spots in the rawhide covering indicate either moisture damage to the wood beneath or separation of the rawhide from the tree. Either requires professional evaluation before riding.
Fiberglass Trees
Fiberglass trees, introduced widely in the 1960s and 70s, replaced wood as the standard in most production saddle manufacturing. A fiberglass tree consists of a wood core covered in fiberglass cloth and resin, sometimes without the rawhide covering used on traditional trees.
Fiberglass trees are lighter than rawhide-covered wood, less expensive to produce, and resistant to moisture. Their failure mode is different from wood: rather than cracking with creaks and pops, a fiberglass tree tends to fracture more suddenly — though the tree-flex test still detects compromised integrity. Delamination (the fiberglass separating from the core) is another failure mode not found in rawhide trees.
Flex Trees
Flex trees are a modern innovation, most prominently marketed by Circle Y (Flex2), Tucker Saddlery, and others. Rather than a completely rigid tree, a flex tree incorporates a degree of lateral give in the bars — typically achieved through a flexible material connecting the bars, allowing them to move slightly relative to each other.
The claimed benefit is that the tree adapts to the horse's back movement, reducing pressure points during motion. The debate over whether this benefit is real or marketing is ongoing in the equine community. What is clear is that flex trees require a different approach to the tree-flex test — some flex is by design. Ask the manufacturer about the expected range of flex for that model, or compare against a known-good example.
Ralide Trees
Ralide is a trade name for a thermoplastic tree material used in some production saddles. It's injection-molded into the tree shape, meaning it can be produced more consistently and inexpensively than hand-built wood or fiberglass trees. Quality Ralide trees are durable; lower-quality versions can flex excessively under rider weight. It's primarily found in budget and mid-range production saddles.
The Importance of Tree Integrity When Buying Used
Regardless of tree material, a compromised tree makes a saddle unsafe and non-repairable for riding purposes. When buying any used western saddle, the tree test is the first and most important step. No amount of beautiful leather, silver hardware, or attractive pricing compensates for a structurally unsound tree. Test every saddle, every time, no exceptions.