This was a flawed theory that was quickly disproven.
So for the past year, Tony (and anyone who knows him) has been considering different ways to rid the rocks of these needles. He thinks they are an eyesore, but us friends don't really notice them much. I guess truth is in the eye of the beholder.
Tonight I somewhat jokingly suggested that he just spray some gas or lighter fluid over the rocks and light them on fire as a sort of "controlled burn" like they do in the wilderness with downed trees, etc. Tony's face switched into the cheshire grin he wears when he is about to do something mischievious. He darted into the house and within minutes was back with some charcoal lighter fluid and his long lighter.
The results of our "test section" ? It actually worked quite well.
I had the hose on ready to douse any problem areas, but there never were any. The pine needles were 90% disintegrated, with a few areas that remained untouched ... but Tony wasn't as specific with the lighter fluid so that can be overcome. The one downside (besides the looks we got from a few neighbors and passing vehicles) was that the burn has to be put out relatively soon after it starts to prevent the weed barrier under the rocks from catching fire.
One section did get a little singed and the smoke from that was quite noxious!
I'll update you later if and when Tony and I "finish the job!" His wife Mindy wasn't entirely against the idea, but she wasn't as excited as we were about the prospect of doing the whole yard that way. Silly Mindy!
After all, we are (self proclaimed) professional fire dudes! :)