Across the West, Basque immigrants worked as sheepherders from 1800s to the 1960s. Many carved their names and etched drawings on the soft white bark of aspen trees. These Basque tree carvings are a memorial to the legacy of those men who endured a solitary lifestyle, roaming the mountains and grassy meadows with their flocks. But the carvings are threatened: Aspen trees are dying by the tens of thousands, crowded by large pines and devastated by parasitical insects.