winter

[rayheinrich]

One possible interpretation (all others are welcome) uses
the dual meaning of 'letter' as a pivot. Bare winter branches can
look like individual characters of words (especially Japanese) and
taken together they might form the words of a postal letter.
Spring wrote them and enclosed them in envelopes of leaves.
There they sit, unread, until winter opens them. (Hmm, actually it's
autumn that opens them, but the bareness of 'branch letters' seems
most evident to me in winter so...) Anyway, something like that.
Happy you liked.