Meaning of 青じろい in 風の又三郎


In one of 宮沢賢治's stories, the following sentence appears:

[code]

    そのとき風がどうと吹いて来て教室のガラス戸はみんながたがた鳴り、
    学校のうしろの山の萱や栗の木はみんな変に青じろくなってゆれ、
    教室のなかのこどもはなんだかにやっとわらってすこしうごいたようでした
    
[/code]

My question is as to what the meaning of 青じろく (青白く) is here.

The technical definition of this word seems to be "bluish white" or "pale",
however in context I don't understand why the trees "paled strangely".

Are the trees "paling" because their leaves are turning over due to the wind?
Or for some other reason?

Or would "darken" be a closer English word to express this usage?




It seems to me like a rhetorical figure more than anything. I can't say
anything for a certainty, but 「青白い」 calls to my mind such ideas as "ghastly",
"spooky", "eerie", so it could be alluding to the (suspected) true identity of
高田三郎 the new transfer kid, which is, as Wikipedia puts it,
「地元で伝説となっている風の神様の子。神というよりも悪霊に近い存在。」

(I haven't read the novel, by the way. So the entirety of my knowledge of the
story consists almost wholly of the quote and what's written on the Wikipedia
article. Yay!)




It seems to me like a rhetorical figure more than anything. I can't say
anything for a certainty, but 「青白い」 calls to my mind such ideas as "ghastly",
"spooky", "eerie", so it could be alluding to the (suspected) true identity of
高田三郎 the new transfer kid, which is, as Wikipedia puts it,
「地元で伝説となっている風の神様の子。神というよりも悪霊に近い存在。」

(I haven't read the novel, by the way. So the entirety of my knowledge of the
story consists almost wholly of the quote and what's written on the Wikipedia
article. Yay!)

