Well...for the tree to crack originally it either was faulty to start with or someone did a job on it to made it crack!
If you truly like the saddle and it fits the horse, why not just get a price to put a new tree under it?
It would certainly be cheaper than purchasing a new saddle and possibly cheaper than purchasing a second hand quality saddle that is well worn...
Why not contact "Circle Y" and see if they will stand behind their product...you never know till you ask.
So far the saddle has cost you nothing... a phone call is cheap enough to do.