Nyororin,
After submitting my reply I figured out you will do such a reply. You are studying linguistic and words should be used precisely :)
OK I should have wrote "the word yama also refers to" instead of "the word yama has another meaning". I'll edit the post.

Then what about what I was saying regarding the forest? Does the word means "forest" or it just refers to "forest" in ancient Japanese ?

It also referred to "forest" in the past, but mainly because 90% of forests are on mountains. :D That meaning lingers in certain modern words, such as 山火事.
I personally wouldn`t use "yama" in that part of the article at all - you`ll still be linking it to the word and not the location as it should be. I would say that in the past, mountains were thought of as ... instead of even bringing up the word. The word "yama" isn`t saying anything more than "mountain" - what you want to convey is that mountains were thought of as such locations.

Anyway, good to know that you weren`t just creatively translating to make Japan look like a mystical magical oriental world of mystery (as is all too common these days.)

ETA; I re-read, and do think that the forest part is also a bit too... overdone. :D The dictionary definition isn`t quite saying what you have interpreted it as. The meaning of forest with great resources is more linked to 山の幸 in contrast to 海の幸. The 山 in that phrase refers more to forest than actual "mountain" in reference to resources - but I wouldn`t go as far as to say it was ever "a place of luxuriant vegetation which brings godsend" - more like a location with much natural plant resources.

Nyororin,
Thanks for your feedback. It was very helpful. I modified the post according to your comments.

Mugen, have you done any long distance hiking in Japan?

One of my goals is to hike the entire length of the Tokaido Shizen Hodo. I'd also like to do some high level ridge traverses in the kita Alps but for now, I'm planning an ascent of Mt. Fuji this November after it closes to the general public.

spicytuna,

Yes, I did some long distance trek in Japan but it was a while ago. I did some in the Southern Japanese Alps, Hokkaido and some mid-distance trek in Hachimantai in the winter. In Northern Alps the longest hikes I did were 3 days long.