Approaching the Crossroads

One thing I've noticed since we started perambulating about the perimeter or Mordor - Tolkien uses more spondees and sprung rhythm to heighten the tension, almost every sentence, then lets the language run again, suggesting the hobbits' slowing and dashing from shadow to shadow:

As the third stage of their day’s march drew on and afternoon waned, the forest opened out, and the trees became larger and more scattered. Great ilexes of huge girth stood dark and solemn in wide glades with here and there among them hoary ash-trees, and giant oaks just putting out their brown-green buds. About them lay long launds of green grass dappled with celandine and anemones, white and blue, now folded for sleep; and there were acres populous with the leaves of woodland hyacinths: already their sleek bell-stems were thrusting through the mould... 

A deep dim valley lay before them. On its further side the woods gathered again, blue and grey under the sullen evening, and marched on southwards. To the right the Mountains of Gondor glowed, remote in the West, under a fire-flecked sky. To the left lay darkness: the towering walls of Mordor; and out of that darkness the long valley came, falling steeply in an ever-widening trough towards the Anduin. At its bottom ran a hurrying stream: Frodo could hear its stony voice coming up through the silence; and beside it on the hither side a road went winding down like a pale ribbon, down into chill grey mists that no gleam of sunset touched.

It would be interesting to see what he could have accomplished, had he been a good writer.