This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
樰 is a rare character composed of 木 (tree) and 雪 (snow). It likely refers to a type of tree associated with snow, but the exact historical development is uncertain.
A tree 木 covered in snow 雪: 樰 might be a snow-covered tree.
For たら, imagine a snow-covered tree with a tarp (たら) draped over its branches to protect it from the snow.
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