Sure, but it would be useful to see if the poster in this case is pulling the idea that it cannot be done out of his arse or has some actual references and anal

Sure, but it would be useful to see if the poster in this case is pulling the idea that it cannot be done out of his arse or has some actual references and analyses of, I don't know, the wear and stresses a typical bridge undergoes, the strain and erosion certain trees have been known to handle. Or perhaps if someone had attempted it before and failed, that would be a good reference. Literally anything to show that it's not complete and utter conjecture would suffice. The mere fact that Western Society can't or hasn't done something doesn't imply that it's impossible. It's a reasonably well known fact that the indigenous people of america had almost no encounters with any sort of plague or disease like that of the black plague, measles, or smallpox, something that would seem impossible without the knowledge of the structures of their cities and their relationship with cattle.