The problem isn't that humans release carbon or other pollutants (burning trees, coal, oil, etc), it's the scale we do it at, and that we don't automatically re-capture it without doing extra work like planting more trees.
But wouldn't a tree be more likely to grow, and in the long run the expected number of trees in a forest be unaffected by the felling of any given tree? (the same can't necessarily be said for the felling of hundreds of trees of course).
you mean "the chemicals" that came from nature in the first place ?
Cyanide is also "natural" but not great for our health depending on the context. The same for the "chemicals" that, when burned, cause some nasty stuff compared to if it wasn't burned.
* I love burning wood.
