木 vs 樹 for trees


It seems that one difference between the usage of 木 and 樹 is that while both
mean tree, the former is also used to mean wood. My question is, is there a
further distinction for living trees?

I'm reading 風の又三郎 and 宮沢賢治 uses both the characters 木 and 樹 for a living tree.
For example in one passage

> 耕助(こうすけ)はうらめしそうに木を見上げました。

Then, 3 lines later, referring to the same tree,

> 耕助(こうすけ)は樹の下をはなれてまた別のやぶでぶどうをとりはじめました。

Is there some nuance I'm missing, or explanation for the choice of characters?

**Update:** (in case anyone is interested in why both were used in this text)
naruto said in a comment below there is no reason to alternate between 樹 and
木, and pointed out only 木 appears in the 青空文庫 version. One possible reason for
the use of both is that the manuscript was never finished by the author, and
there were still inconsistencies in the original version, and that this is one
of them (my version said it was minimally edited). Note [this online
原文](http://www5a.biglobe.ne.jp/accent/kazeno/origin.htm) uses both 樹 and 木 as
I indicated above.




When used alone, 樹【き】 is a literary expression mainly found in novels, lyrics
and poems. For living trees, we use 木 in everyday writings.

And probably 樹 is mainly used to refer to a large and grown tree. I feel one-
meter high tree is less likely to be called 樹.




When used alone, 樹【き】 is a literary expression mainly found in novels, lyrics
and poems. For living trees, we use 木 in everyday writings.

And probably 樹 is mainly used to refer to a large and grown tree. I feel one-
meter high tree is less likely to be called 樹.

