Cork Oak Quercus suber Fagaceae Sarah Stacionis ID z Look for: - Live oak trees with thick, spongy bark, - shiny evergreen leaves with whitish undersides and spiny margins, and - acorn cupules that bristle outwards. z broad, spreading tree with an open canopy and thick, corky bark. Older trees become very picturesque and elegant, with the grey-green, evergreen foliage contrasting well with the deeply-fissured, grey-to-tan bark. Cork Oak Facts z Grown in Mediterranean countries/areas: – Portugal, Spain, Italy, North Africa, and California z Sunset zones: 5-7, 8-16, 18-24 z Long-lived trees: over 200 years z Coastal and inland environments. Adapted to heat, cold, aridity, and drought. Prefers slightly acid soils. Requires good drainage. z One of the best oaks for deserts z Evergreen, grow to 30-60 or 60-80 ft. tall depending on area planted, broad canopy-so like most other oaks, it needs its space! The Trunk z Tree bark is the cork z Great insulator: protects inner bark from forest fires and hot dry summer winds z Resistant to moisture and liquid penetration Harvesting the cork z Cork is harvested or “stripped” by hand with a specialized cork axe z It is stripped for the first time after 25 years of growth, then again every 9-12 years z The cork strips are “left out in the open air for six months. This weathering process actually improves the cork’s quality” z It is then sorted and first used to produce cork stoppers z Left over cork is ground up and used for things like bulletin boards and construction materials z The demands of the world’s wine and champagne industries requires about 13 billion cork stoppers annually. z FACT: A mature Cork Oak provides enough cork to make 4,000 bottle stoppers per harvest!!!! Other Uses for Cork z Romans used cork to/for: – Insulate homes – Insulate bee hives – Soles for shoes – Stoppers for bottles – Pitchers – Vases – Floats for fishing nets – Buoys for navigation Cork Oaks on Campus z Lining the east and west side of the quad z East Quad cork oaks (in front of North and South Hall—the original dorms) were planted around the quad in 1925 (listed as #23 the UC Davis Campus Tree Walk) z They replaced the palm trees that had been there z Two probably largest on campus between the MU and Hickey gym z Babies planted next to Science Lecture hall z EVERYWHERE Problems with Campus Cork Oaks z Too small/narrow planting beds z Compacted roots and reduced fine root hair volume due to high traffic decomposed granite covered areas z Phytophthora root rot in irrigated lawn areas (the quad)—symptom is yellow/chlorotic foliage, small leaves, low vigor, twig dieback, and death if untreated z Highly alkaline soils can cause yellowing as well (prefer slightly acidic soil) z Broken out branch cavities being filled-callus formation z Included branches/trunks Cork Oaks in and Around Downtown Davis z Downtown Davis Treewalk with TREE Davis #10 on the map @ 240 2nd Street Believed to have been planted in the 1930’s z An impressive stand can also be seen on East Olive Drive Other forms of the Cork Oak z Bonsai z Topiary trees/sheared canopies References z Berry, Alison; Acton, Zeno; Schwartz, Kevin; Sutherland, Andrew. ENH 133: Woody Plants in the Landscape. Winter Quarter 2007. Class lectures and lab. z Brenzel, Kathleen N. Sunset: Western Garden Book. Sunset Publishing Corporation. Menlo Park, CA. 2001. P. 562 z Cork Institute of America. Harvest. <http://www.corkinstitute.com/harvest.html> z Environmental Horticulture: Introduction to Environmental Plants. Maintained by the Department of Plant Sciences at the University of California, Davis. 2008 <http://www.plantsciences.ucdavis.edu/courses/enh6/Week3/quersube.html> z James Will, John Fitzgibbon and John Brereton. Quercus suber: Cork Oak. Copyright ©2007 Metropolitan Tree Growers Pty Ltd. <http://www.metrotrees.com.au/treehandbook/page-listings/quercus-suber.html> Niels Proctor. z Tony Russell, Catherine Cutler, and Martin Walters. The New Encyclopedia of American Trees. Arnness Publishing Ltd. 2005, 2006. P. 43. z TREE Davis. Downtown Davis Treewalk pamphlet. 2008. z UC Davis Campus Tree Walk. 2008 <http://facilities.ucdavis.edu/bldg_grnds/grounds/Treewalk%20Site%202-24-05/treelist/index.html>.