Tom Hillman points out an embarrassing omission in the post about forests:

Of course, I left out the Forest of Drúadan.  It’s unique in LotR, in that trees are the only species Tolkien mentions there.  (Not counting the grass in the Woses’ skirts.)  It’s just a place where things happen.  The other forests Olga and I talked about are much more than that.  They’re practically characters in the story. Drúadan seems more like the old-growth American forests that we saw in The Last of the Mohicans: Large trees, well spaced, with not much undergrowth.

So there’s another question for me to think about:  Is the Forest of Drúadan so bland because JRRT has a battle to get to, and has no time for dawdling?  Or is the forest really a tamed human habitation, between being used as a quarry by the Men of Gondor, and continuously inhabited by Woses?