elm, gum
樠 centers on a type of tree, specifically elm or gum trees. The meanings are narrow botanical references rather than a broad conceptual idea.
樠 combines 木 (tree) with 㒼, which likely contributes the sound. The character is used for specific tree names, but the exact historical development of 㒼 is uncertain.
The left side 木 is a tree. The right side 㒼 looks like a dense, spreading canopy. Picture a tall elm or gum tree with a thick crown of leaves.
For ボン, imagine a bonsai elm tree: bonsai -> ボン, and the tiny tree still has the same distinctive shape as the full-sized 樠.
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