Wait, what?! The statement that there are trees in the forest should not be older than the statement that a god put them there, because the claim that a god out them there could not be disproven? What was first: the perception and realisation that there are trees, or the question why they are there?

Only one of the two optional answers is correct.
Haplo, is this another of your queer attempts to put belief on same and equal status eye to eye with reason and knowing? Man, I really wish you would leave believing as what it is : just believing something. Nothing more it is.
Claims on deities having been the cause of something, are something that is being added to the existing world that already has been there before there was an organism as advanced enough to wonder why there is a world - the question why it is there cannot appear before somebody found that a world exists for sure. The one we live in, that is. Before you can ask questions on the existence of something - you must have taken note of its existence.
Natural drive to reproduce, and desire in humans (all this clever trickery of natrure that brings us together with another being to contribute to the survival of the species

), without any doubt is much older than any claim, idea, concept on monotheistic and before: polytheistic deities, theories on solar sunspot activity, and the invention of book printing. That we can say with great certainty for a simple reasopn: we can give relatively precise dates for when polytheistic theologies first developed, and when the first monotheistic concepts appeared, and when the later started to seriously push back the first. And yes, before monotheism there was polytheism. And there was a time with humans living that did not even know any form of theism at all.