There are three beams that make up the structure of the arched bridge. Two beams, the left and middle, have extensive rot damage at the ends. The left beam has been affected by three feet or more going across and is the worst of the two. The middle beam is not as bad but still has considerable damage on the end almost by almost a foot. The right beam is fine. The cause of the damage is dirt and mulch being pushed up against the ends and bottom. It's surprising that the structure has not shifted and is still holding up.
What is the best procedure and treatment to restore the end pieces?
Photos can be provided