There are some by-products that are produced when wood is burned, that inhibit the growth of bacteria. Odor is caused by bacteria, some more offensive than others. Carbon is also a by-product of wood being burned.
Let me say, at this point that I DO NOT believe that ANYTHING can totally eliminate the human smell that we produce, just by living our lives. I believe that our breath is something that gets us busted a lot more than we realize.
Take a shower and wash with perfume free soap, smoke yourself and all of your gear that you are carrying with you. You might be surprised at the results.
I am absolutely sure that the animals can smell the smoke, but don't seem to be afraid of the smell, or associate it with danger. I know, doesn't make sense, but here in WV and Ohio, there isn't any place that I hunt that doesn't have the smell of wood smoke in the air in the fall and winter.
This has been beat to death on another forum that I spend time on......the truth is, it works and it really doesn't matter why to me.
Winterhawk1960