A wood is smaller than a forest. Forests are larger, denser and more impenetrable than woods. We also tend to use the word 'wood' or 'woods' for Northern Hemisphere-style trees. For example, if you are talking about Brazil or Indonesia, you would use the word 'forest', not 'wood'.

There's no real difference. They are basically synonyms.

I don't think there's a difference. With regard to origin, Longfellow begins "Evangeline" with the words "This is the forest primeval," and he is talking about Acadia--Nova Scotia in the 1600s--so his "forest primeval" is obviously natural, not planted. Ditto for any "rain forest." Meanwhile, Wikipedia tells me, http://en.wikipedia.org/wiki/Maine_North_Woods , that the Maine North Woods "covers more than 3.5 million acres (14,000 km²) of forest land," so a "woods" isn't necessarily small. ahdictionary.com gives two definitions which are delightfully inconsistent. a. A growth of trees and other plants usually covering a smaller area than a forest. b. A forest.

What the author means is the forests are planted by humans (I do not agree with him/her) and feels that woods are just the development of nature. I have never heard this before, but it is what I think the author means. And, the word planned is spelled with the two nn's.

It depends on the contest how it is used. We have a idiom (which I used earlier today talking with my brother) you can't see the forest for the trees). That means a person does not see the clear picture of anything because he is focused on the little stuff. So, he does not see the big picture - the forest as he is focused on seeing one tree.