The landscape has changed since USR1 lived here.

The specific configuration of spruce and birch in the valley — the tree line, the wetland margins, the river channels — is different from what it was 11,500 years ago, when the early Holocene warming was still transforming the late Pleistocene vegetation into the modern subarctic forest.

The river itself has shifted in its channel multiple times since then, as rivers do.

The animals that used the valley have changed — the woolly mammoths and horses of the late Pleistocene were gone by the early Holocene, replaced by the moose and caribou and bears and salmon that define the modern Alaskan interior ecosystem.