This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
桗 combines 木 (tree) with 朶, but the historical origin and original meaning are uncertain. It may be a phono-semantic compound, but the exact development is unclear.
The left side is a tree 木, and the right side 朶 looks like a drooping branch. Imagine a tree with a hanging branch, but its exact meaning remains obscure.
For タ, picture a tar-like substance dripping from the drooping branch of the tree: tar -> タ.
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