Shattil & Rozinski / Fallen Aspen leaves {Populus tremula} on rocks in river in autumn, USA

Shattil & Rozinski / Aspen tree {Populus tremula} leaves and trunks in autumn, USA

Larry Michael / Autumn colours reflected in river water, Ontonagon River, flows into Lake Superior. Michigan, USA.

Shattil & Rozinski / Heavy snow on branch, Colorado, USA, December

Shattil & Rozinski / Frozen ice at waterfall, Colorado, USA, December

Shattil & Rozinski / Frost and snow flakes on feather, Colorado, USA

Shattil & Rozinski / Heavy snow on branch, Colorado, USA, December

Shattil & Rozinski / Ice formed round plant twigs, Colorado, USA

Shattil & Rozinski / Water frozen into icicles over river, Colorado, USA

John Cancalosi / Rubber Boa (Charina bottae) coiled within itself, Oregon, USA, captive

John Cancalosi / Details of Bald-faced Hornet's nest (Dolichovespula maculata) Oregon, USA

John Cancalosi / Details of Bald-faced Hornet's nest (Dolichovespula maculata) Oregon, USA

John Cancalosi / Details of Bald-faced Hornet's nest (Dolichovespula maculata) Oregon, USA

John Cancalosi / Sandstone rock formations showing layers of rock, Zion National Park, Utah, USA

Jack Dykinga / Twisted roots of Bristlecone pine {Pinus aristata var. longaeva} cling to cliff edge at Rainbow Point, Bryce Canyon National Park, Utah, USA

John Cancalosi / Close up of ice on branch, NY, USA

Shattil & Rozinski / Fallen Aspen leaves {Populus tremula} on rocks in river in autumn, USA

Shattil & Rozinski / Sugarbowl clematis flower {Clematis hirsutissima} Colorado, USA

Shattil & Rozinski / Aspen tree {Populus tremula} fallen autumn leaves, USA

Shattil & Rozinski / Aspen tree {Populus tremula} fallen autumn leaves, USA

Shattil & Rozinski / Aspen tree {Populus tremula} after the first snow of winter, Colorado, USA

Shattil & Rozinski / Fallen Aspen leaves {Populus tremula} on rock in river, San Luis Valley, Colorada, USA

Shattil & Rozinski / Bubbles of air caught in pond ice, Colorado, USA

Shattil & Rozinski / Fallen Aspen leaves {Populus tremula} on rocks in river, Colorada, USA

Shattil & Rozinski / Leaves of Aspen tree {Populus tremula} in autumn, USA

Shattil & Rozinski / Aspen tree {Populus tremula} with the first snow of winter, USA

Shattil & Rozinski / Leaves of Aspen tree {Populus tremula} in autumn, USA

Shattil & Rozinski / Fallen Aspen leaves {Populus tremula} on rocks beside river, Colorada, USA

Shattil & Rozinski / Morning glory {Ipomoea sp} close up of flower, USA

Shattil & Rozinski / Fairy slipper orchid {Calypso bulbosa} close up of flower, USA

Shattil & Rozinski / Fairy slipper orchid {Calypso bulbosa} close up of flower, USA

Thomas Lazar / Sand ripples and ridges in white gypsum sand dune, White Sands National Park, Chihuahuan Desert, New Mexico, USA

Thomas Lazar / Ripples and ridges in the sands of White Sands National Park, Chihuahuan Desert, New Mexico, USA

Thomas Lazar / Pink pre-dawn light on Soaptree yucca (Yucca elata) growing on rippled covered white sand dune, White Sands National Park, Chihuahuan Desert, New Mexico, USA

Thomas Lazar / Wind blowing sand over the ridge, White Sands National Park, Chihuahuan Desert, New Mexico, USA

Thomas Lazar / Last light of day lighting ripples on curved white sand dunes, White Sands National Park, Chihuahuan Desert, New Mexico, USA

Thomas Lazar / Ripples in white sand running down side of large rounded dune, White Sands National Park, Chihuahuan Desert, New Mexico, USA

Thomas Lazar / Autumn leaves on branch overhanging waterfall, Bond Falls, Upper Peninsula, Michigan, USA

Thomas Lazar / High winds (50-60 mph) create irregular ripples and patterns running up white gypsum sand dune, White Sands National Park, Chihuahuan Desert, New Mexico, USA

Thomas Lazar / High winds (50-60 mph) create irregular ripples and patterns running up white gypsum sand dune, White Sands National Park, Chihuahuan Desert, New Mexico, USA

Thomas Lazar / Ripples in white sand running down side of large rounded dune, White Sands National Park, Chihuahuan Desert, New Mexico, USA

Thomas Lazar / High winds (50-60 mph) expose irregular ridges and layers in wet sand receding to white dunes. White Sands National Park, Chihuahuan Desert, New Mexico, USA

Thomas Lazar / Ripples in white sand running down side of large rounded dune, White Sands National Park, Chihuahuan Desert, New Mexico, USA

Thomas Lazar / Ripples on white sand dunes running down to Alkali Flat with San Andres Mountains behind, White Sands National Park, Chihuahuan Desert, New Mexico, USA

Shattil & Rozinski / Great blue heron {Ardea herodias} fishing, Colorado, USA

Shattil & Rozinski / Bluebonnet / Lupin flowers {Lupin sp} and Paintbrush flowers {Castilleja sp} in wildflower meadow, Texas, USA, 1997

Shattil & Rozinski / Paintbrush flowers {Castilleja sp} and Bluebonnet / Lupin flowers {Lupin sp} in wildflower meadow, Texas, USA, 1997

Juergen Freund / Red skies after sunset over the Pacific Ocean from Vancover Island, British Columbia, Canada.

Tom Vezo / Silhouette of duck on water at sunset, Salton Sea, California, USA