Ah, Grasshopper, I see potential confusion...
quote:
...the reaction and so forth to make the ring from the heat source and not the wood
Nope you've got it backward. The wood not the heat creates it. Don't know about "oxides" causing it, but I do know about Nitrates/Nitrites doing the work.
The difference is that it's not Heat that creates nitrates/nitrites. Electricity burning a heating element creates none of that. Proof? That's why a Cs doesn't create a SR.
What does? Go to the first link above.
Wood/Charcoal and other artificial sources will work their magic.
That's why putting in a piece of charcoal works better than just a piece of wood. Oz for Oz it will put out more Nitrites than wood, until wood hits the charcoal stage (but then it's smaller)