• 07.117 in the direction of the pine-woods on the east side of the Misty Mountain
• 14.040 right to the pinewoods of the Misty Mountains;

I am intrigued that Tolkien uses it in the same sense of “woods of pine trees” – even the same woods – with two spellings.  The OED has it hyphenated, one-word, and two-words.

“pinewood, n. and adj.” OED Online, Oxford University Press, June 2017, http://www.oed.com/view/Entry/144125. Accessed 19 September 2017.