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 Mu?lovcica 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), Monte Sacro, Gargano National Park, Gargano Peninsula, Apulia, Italy, April 2008

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

Duncan Usher / Eurasian Jay (Garrulus glandarius) flying with an acorn in its bill, Hessen, Germany

Jasper Doest / Coast Live Oak (Quercus agrifolia), George West, Texas

Silvia Reiche / Purple Hairstreak (Neozephyrus quercus)butterfly on Forget-me-not (Myosotris sp) flower, Hoogeloon, Noord-Brabant, Netherlands

Duncan Usher / Great Spotted Woodpecker (Dendrocopos major) female carrying nut, Lower Saxony, Germany

Silvia Reiche / Purple Hairstreak (Neozephyrus quercus) egg, Hoogeloon, Noord-Brabant, Netherlands

Silvia Reiche / Purple Hairstreak (Neozephyrus quercus) butterfly egg on tree bud, Knegsel, Noord-Brabant, Netherlands

John Waters / Oak tree (Quercus sp.), probably several hundred years old, near Blagdon Lake, Somerset, UK, March.

Adrian Davies / Hen of the woods fungus (Grifola frondosa) at base of Oak (Quercus sp) tree. Sussex, England, UK. October.

Adrian Davies / Oak bracket fungus (Inonotus dryadeus) at base of Oak (Quercus sp) tree. Surrey, England, UK. August.

Andy Sands / Slime mould (Trichia botrytis) sporangia starting to split to release spores, on underside of rotting Oak (Quercus sp) log. Hertfordshire, England, UK. December. Focus stacked image.

Andy Sands / Slime mould (Physarum sp), sporangium on Oak (Quercus sp) twig, close-up. Buckinghamshire, England, UK. December. Focus stacked image.

Andy Sands / Cup fungus (Lachnum rhytismatis) on rotting Oak (Quercus sp) leaf. Buckinghamshire, England, UK. September. Focus stacked image.

Andy Sands / Slime mould (Comatricha longipila), mature sporangia on rotting Oak (Quercus sp) log, Hertfordshire, England, UK. November. Focus stacked image.

Graham Eaton / Oak (Quercus sp) trees in a row beside Sandstone Trail long distance footpath. Near Bickerton, Cheshire, England, UK. December 2019.

Adrian Davies / Purple toothwort (Lathraea squamaria), parasitic on roots of Oak (Quercus sp). In botanic garden, Surrey, England, UK. March.

Robert Thompson / Deyrolle's emperor moth (Pseudimbrasia deyrollei) caterpillar feeding on Oak (Quercus sp) leaf. , Northern Region, Ghana.

Robert Thompson / Saturniid moth (Lobobunaea phaedusa) caterpillars on Oak (Quercus sp) leaf, early instar larvae. Ashanti Region Ghana, Africa. Controlled conditions.

Robert Thompson / Io moth (Automeris io) caterpillars on Oak (Quercus sp) leaf. Montreal, Quebec, Canada. June. Controlled conditions.

Jeff Foott / Mexican flag against blue sky. Coat of arms on flag depicting a Golden eagle (Aquila chrysaetos) feeding on Rattlesnake (Crotalus sp) whilst perched on a Prickly pear cactus (Opuntia sp), Oak (Quercus...

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