If you're going to make a meaningful point any time soon, then do so and stop wasting my time trying to be cute.
I always found it hard to belive [sic] that forests in one part of the world were supplying oxygen for the rest of the planet.
Perhaps you're implying that some people hold the view that the rain forests are responsible for a very large portion of the oxygen in the atmosphere, and this you find hard to believe. If so, I apologize for supposing that you were overlooking an aspect of physical chemistry.