Solvin Zankl / Great capricorn beetle (Cerambyx cerdo) on Oak tree (Quercus sp) Niedersachsische Elbtalaue Biosphere Reserve, Lower Saxonian Elbe Valley, Germany, July.

Theo Bosboom / Oak tree (Quercus sp) with snow in autumn, Rozendaalse Bos, near Arnhem, the Netherlands, November

Fabrice Cahez / Oak (Quercus sp) forest at dawn, Vosges, France, January

David Woodfall / Ancient semi natural woodland in mist with Oak (Quercus sp) and Hornbeam (Carpinus betulus). Romania, October 2010

Neil Lucas / Ancient Oak tree (Quercus) Savernake Forest, Wiltshire, UK

Stephen Dalton / Oak tree {Quercus sp} seedling, UK

Wild Wonders of Europe / Hermansen / View looking up into Oak (Quercus sp) canopy, Glendalough valley, County Wicklow, Ireland, June 2009

Wild Wonders of Europe / Lilja / Kermes oak (Quercus coccifera) trees, Kritsa, Crete, Greece, April 2009

Wild Wonders of Europe / Lilja / Kermes oak (Quercus coccifera) Kritsa, Crete, Greece, April 2009

Wild Wonders of Europe / della Ferrera / Slavonian / Common oak (Quercus robur) and Ash (Fraxinus sp) forest, near Mužilovcica village, Lonjsko Polje Nature Park, Sisack-Moslavina county, Slavonia region, Posavina area, Croatia, June 2009

Wild Wonders of Europe / Maitlan / Oak leaves and lichen in forest, Konjsko region, Galicica National Park, Macedonia, June 2009

Wild Wonders of Europe / Radisics / Oak tree, the oldest tree in Hortobagy National Park, Hungary, July 2009

Jack Dykinga / Velet-pod mimosa (Mimosa dysocarpa) flowering amongst Blue oak trees (Quercus oblongifolia) Atascosa Mountains, Coronado National Forest, Arizona, USA

Jack Dykinga / Velet-pod mimosa (Mimosa dysocarpa) flowering amongst Blue oak trees (Quercus oblongifolia) Atascosa Mountains, Coronado National Forest, Arizona, USA

Wild Wonders of Europe / Rautiainen / Oak (Quercus sp) Matsalu National Park, Estonia, May 2009

Juan Carlos Munoz / Large oak tree {Quercus sp} with ferns growing on trunk, Alcornocales NP, Cadiz, Andalucia, Spain

Juan Carlos Munoz / Large oak tree {Quercus sp} with ferns growing on trunk, Alcornocales NP, Cadiz, Andalucia, Spain

Wild Wonders of Europe/ Bartocha / Downy oak (Quercus pubescens) surrounded by wild flowers, Monte Sacro, Gargano National Park, Gargano Peninsula, Apulia, Italy, April 2008

Wild Wonders of Europe/ Bartocha / Downy oak (Quercus pubescens) surrounded by wild flowers, Monte Sacro, Gargano National Park, Gargano Peninsula, Apulia, Italy, April 2008

Wild Wonders of Europe/ Bartocha / Downy oak (Quercus pubescens), Monte Sacro, Gargano National Park, Gargano Peninsula, Apulia, Italy, April 2008

Adam Burton / Silhouetted oak trees reflect in pond, New Forest National Park, Hampshire, England

Jack Dykinga / Summer poppies (Kallstroemia grandifolia) and oaks (Quercus sp) after record summer rains in the Coronado National Forest, Arizona

Jack Dykinga / Oak tree (Quercus sp) in the San Isidro Canyon, Maderas del Carmen Natural Preserve, Coahuila, Mexico

Jack Dykinga / Velvet-pod mimosa (Mimosa dysocarpa) flanked by Blue oaks (Quercus oblongifolia) in the grassy foothills of the Atascosa Mountains, Coronado National Forest, Arizona

Kirkendall-Spring / Oak Tree {Quercus sp} in a meadow amid California Poppies {Eschscholzia californica}, Henry W. Coe State Park, California, USA

Kirkendall-Spring / Oak Tree {Quercus sp} growing at Paramount Ranch, Santa Monica Mountains National Recreation Area, California, USA

Jeff Foott / Coast Redwood (Sequoia sempervirens) and Oak (Quercus sp) trees, Redwood National Park, California

Jim Brandenburg / Oak (Quercus sp) leaves in stream with snowy forest, Minnesota

Mark Moffett / Northern Red Oak (Quercus rubra) tree with corns and leaves at base of it, Massachusetts

Mark Moffett / Northern Red Oak (Quercus rubra) tree with corns and leaves at base, Massachusetts

Sven Zacek / Oak (Quercus sp), mature tree covered with fresh snowfall, in evening light. Near Halliste River, Soomaa National Park, Viljandimaa County, Estonia. February.

Juan Carlos Munoz / Oak (Quercus sp) forest with trees coming into leaf in spring, surrounded by Eucalyptus (Eucalyptus sp) plantation. Cueva la Cubilla, Samano, Castro Urdiales, Cantabria, Spain. April 2019.

Juan Carlos Munoz / Rainbow over Oak (Quercus sp) forest, Mount Candina in background. Liendo Valley, Montana Oriental Costera, Cantabria, Spain. June 2019.

Juan Carlos Munoz / Oak (Quercus sp) trees coming into leaf in field, tractor tracks in grassland, aerial view. La Gandara, Alto Ason, Soba Valley, Cantabria, Spain. May 2019.

Juan Carlos Munoz / Oak (Quercus sp) coming into leaf within grassland, aerial view. Campina, La Gandara, Alto Ason, Soba Valley, Cantabria, Spain. May.

Chris Mattison / Autumn colours in countryside with Oak (Querus sp) tree. Near Monmouth, Monmouthshire, Wales, UK. November 2018.

Chris Mattison / Autumn colours in countryside with Oak (Querus sp) tree. Near Monmouth, Monmouthshire, Wales, UK. November 2018. Digitally stitched image.

Chris Mattison / Oak (Quercus sp) tree and surrounding countryside in autumn. Near Monmouth, Monmouthshire, Wales, UK. November 2018.

Adrian Davies / Oak processionary moth (Thaumetopoea processionea) nest removal from infested Oak (Quercus sp) tree with cherry picker. Surrey, England, UK. July 2018.

Will Watson / Bog Oak (Quercus sp.) beside Llyn y Fan Fach, Black Mountain / Mynydd Du, Brecon Beacons National Park, Carmarthenshire, Wales, September 2018.

Will Watson / Bog Oak (Quercus sp.) in Llyn y Fan Fach, Black Mountain / Mynydd Du, Carmarthenshire, Wales, UK. September 2018.

Sven Zacek / Eurasian pygmy owl (Glaucidium passerinum) perched on lichen covered Oak (Quercus sp) branch. Alam-Pedja Nature Reserve, Tartumaa, Southern Estonia. November.

Sven Zacek / Hawk owl (Surnia ulula) perched on Oak (Quercus sp) branch. Tartumaa, Southern Estonia. November.

Juan Carlos Munoz / Oak (Quercus sp) woodland in autumn with snow, Sierra Cebollera Natural Park, La Rioja, Spain. November.

SCOTLAND: The Big Picture / Ivy (Hedera helix) growing on Oak (Quercus sp) tree in Atlantic oak woodland, Taynish National Nature Reserve, Argyll, Scotland, UK, June.

Doug Wechsler / Acrobat ant (Crematogaster sp) tending aphids on white oak (Quercus sp) Washington State Park, Pennsylvania, USA September

Doug Wechsler / Acrobat ant (Crematogaster sp) tending aphids on white oak (Quercus sp) Washington State Park, Pennsylvania, USA September

Doug Wechsler / Ferruginous carpenter ant (Camponotus chromaiodes) worker feeding at alcohol flux - fermented sap - on white oak (Quercus sp) trunk, Fort Washington State Park, Pennsylvania, USA August