What about wicker? I imagine there to be a whole world of archaeology out there we miss because everything bio-degraded. If you navigated by river and set up a

What about wicker? I imagine there to be a whole world of archaeology out there we miss because everything bio-degraded. If you navigated by river and set up a society based on fishing from the river then you might make everything out of wood, with wicker being the material of choice for seats and other furniture. Such a society could be very sophisticated, as per the people that lived in the Amazon before the white man diseases killed them all for the forest to return to apparently virgin rainforest by the time the white guys got there. So there is your scenario to detect, how would you look out for such a society that had no need for big stone structures? Rivers used to be clear and full of fish, able to service a river dwelling human culture for as long as there are fish. If farming happens the river is no longer clear or full of fish, so a recession of sorts hits rather than some big defining event.