Over three sunny-but-cool October days, a team of scientists and volunteers dug up and hauled away the root crowns of trees along the Crystal River, a first step toward a potential strategy to protect flows on one of the last free-flowing rivers in Colorado. … Environmental and recreation advocates and local municipalities, as well as many residents of the Crystal River Valley, have long sought to protect the river from future dams and diversions — infrastructure projects that have left many other Western Slope rivers depleted.