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|Foliage and acorns of Quercus robur|
Oak trees grow in many parts of Europe and North America. Many people who own wooded land in these parts of the world are proud of their oak trees. Oak is a climax vegetation in much of the northern hemisphere. What that means is, left untouched by humans, it would be the dominant tree. Much of England was covered by oak forests before modern farming took over the land. The last extensive oak woodlands were cut down to build ships for the Royal Navy in the 18th century.
Most oak trees lose all of their leaves in autumn. Some kinds of oak tree, the "live oak", that grows in the American South or the Holm oak that grows in Europe, keep their leaves through winter It is called the "live oak" in the United States of America because it keeps many of its leaves during winter.
Oak trees can live up to 1000 years.
A mature oak tree stands about 100 feet tall (~30 metres). It is a home for more animals than any other European tree. 30 species of birds, 45 different bugs and over 200 species of moth have been found on oaks. Beetles burrow under the bark, and some drill holes into the wood. The leaves are eaten by many caterpillars. Many leaves carry strange little bumps on the underside. These are insect galls, caused by many little animals. Midges, moths, worms and tiny wasps lay their eggs in leaves or leaf buds. The leaf reacts by forming a growth around the eggs. Inside the gall, larvae develop. The leaf falls, but the larvae may come out only the next spring. Small galls only have one larva, but larger galls may contain as many as 30 larvae.
Oak trees produce acorns once a year which ripen in Autumn. Oak trees may start producing acorns when they are about 20 years old. A mature oak may produce 90,000 acorns a year; this is several millions in its lifetime.
|Wikispecies has information on: Quercus.|
- "Key facts about oak trees". http://www.oakdoors.co.uk/_oak-trees-in-history.php.
- "Oak tree facts". http://student.britannica.com/comptons/article-9275054/oak.
- Attenborough, David 1995. The private life of plants. London: BBC Books, 152–158. ISBN 0-563-37023-8
- "Oak tree facts". http://www.arcytech.org/java/population/facts_oaks.html.