Tim Fitzharris / Ponderosa Pine (Pinus ponderosa) trees and Mount Herard, Great Sand Dunes National Park, Colorado

Tim Fitzharris / Quaking Aspen (Populus tremuloides) and Ponderosa Pine (Pinus ponderosa) trees in winter, Santa Fe National Forest, New Mexico

Tim Fitzharris / Quaking Aspen (Populus tremuloides) and Ponderosa Pine (Pinus ponderosa) trees in winter, Santa Fe National Forest, New Mexico

Tim Fitzharris / Ponderosa Pine (Pinus ponderosa) tree and eroded rock formation, Kasha-Katuwe Tent Rocks National Monument, New Mexico

Tim Fitzharris / Ponderosa Pine (Pinus ponderosa) tree in slot canyon, Kasha-Katuwe Tent Rocks National Monument, New Mexico

Tim Fitzharris / Ponderosa Pine (Pinus ponderosa) trees in slot canyon, Kasha-Katuwe Tent Rocks National Monument, New Mexico

Tim Fitzharris / Ponderosa Pine (Pinus ponderosa) trees and cliff, Coconino National Forest, Arizona

Tim Fitzharris / Ponderosa Pine (Pinus ponderosa) trees, Mogollon Rim, Mazatzal Wilderness, Coconino National Forest, Arizona

Tim Fitzharris / Ponderosa Pine (Pinus ponderosa) trees, Mogollon Rim, Mazatzal Wilderness, Coconino National Forest, Arizona

Tim Fitzharris / Ponderosa Pine (Pinus ponderosa) trees, El Morro National Monument, New Mexico

Jeff Foott / Ponderosa Pine (Pinus ponderosa) and Bigtooth Maple (Acer grandidentatum), Utah

Donald M. Jones / Western Bluebird (Sialia mexicana) male in Ponderosa Pine (Pinus ponderosa), Montana