This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
棶 combines 木 (tree) with 來, which likely contributes the sound. The exact historical development is uncertain.
The left side is a tree 木, and the right side 來 looks like a person coming. Picture a tree that people come to, though its exact meaning is uncertain.
For ライ, imagine a line of trees: line -> ライ, and the tree 木 on the left helps you remember the sound.