Conversely, when an environment is built out enough that human artifice becomes the dominant feature, such that even natural features take place there as features cultivated by human deliberation, then the nature of "trash," or what is "out of place" changes in turn. Tree branches and other plant sheddings that are cast aside no longer appear as natural, to degrade on their own terms like on the forest floor. They too appear out of place and as trash - though something perceived as quaint like fallen leaves can stay, at least for a limited amount of time - and must be swept up and disposed of somewhere else.
But other forms of trash, like cut lumber which "belong" in built environments still become trash when they degrade and become "out of place" when they are no longer useful and/or attractive. The more widespread the built environment becomes, the more energy must be expended to put things where they belong and move them elsewhere when they no longer belong. Less and less can simply be left alone to do what it shall.
