It would only be plagiarism if you knew of a prior source and intentionally failed to cite it. I don't think anyone here was accusing you of such. People, independent of one another, often create similar inventions, come up with similar ideas, etc.
Actually, I'm not even sure if you're claiming credit for the idea. Here at least, you only make the claim for the first publication of the idea. Where'd the idea come from? Did it have some popular circulation before it went into print?
Not to add flame to a dying fire (pardon my choice of metaphor), but it would be of interest to me to see both the Backwoodsman and the ASG articles that are alluded to here. Are these both in public libraries?