This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
橊 is a rare character. It visually combines 木 (tree) with 畱, but the historical development and original meaning are uncertain.
The left side 木 suggests a tree or wood, but the overall meaning is unclear. Think of it as a mysterious tree with an unknown name.
For ル, imagine a mysterious tree with a loop-shaped branch: loop -> ル, and the tree's name is a secret.