English oak is the most common tree species in the UK so you're likely to spot one on your day to day travels. it is probably the best known and loved of our British native trees. It's scientific name is Quercus robur and the common names are pedunculate oak, European oak, common oak or English oak. The iconic acorns and lobbed leaves make this a great tree to study and work with.
English oak is a large deciduous tree and can grow up to 40m tall. As common oaks mature they form a broad and spreading crown with sturdy branches beneath. Their open canopy enables light to penetrate through to the woodland floor, allowing flowers such as bluebells and primroses to grow below. The bark is smooth and silvery brown when young and with age becomes rugged and deeply fissured. The growth of oak trees is particularly quick in youth but gradually slows at around 120 years. As they get older they physically shorten with age in order to extend their lifespan. The reason it is also known as the Pedunculate oak is because the acorns grow on stalks or 'peduncles'.
The iconic acorns and lobbed leaves make English oak one of the most well known trees in the UK.
Day or night - English oak is a fantastic tree species to witness.
The leaves are around 10cm long with 4-5 deep lobes with smooth edges. The leaves have almost no stem and grow in bunches. During May English oak bursts into life with all of it's new leaves. English oak is monoecious which means the male and female flowers are on the same tree - just different parts. The male flowers are greenish / yellowish drooping catkins which release the pollen by wind. The female flowers are roundish and stand alone or in pairs and are very inconspicuous. The flowers are usually present in April to May time.
The buds are brownish, ovate-shaped and clustered at the end of the twig.
The lobbed leaves are a very distinct feature of English oak.
The acorns hang on long stems in clusters of up to four usually. Young acorns are green and as they mature they turn brown and are ripe in September / October. The length of the egg-shaped acorns is about 2-3 cm and the fruit cup covers the acorns to a third. The acorns are an important food source for wildlife quite often grey squirrels. The acorns are not produced until the tree is at least 40 years old. Peak acorn production usually occurs around 80 – 120 years. Most acorns will never get the chance to germinate as they are often eaten by wildlife such as jays, mice and squirrels. Following successful germination, a new sapling will appear the following spring.
The bark of English oak becomes furrowed as it matures.
The biodiversity of English oak is massive. Many insects, spiders and birds rely on these great trees.
The value to British wildlife is extremely high as they provide both food and shelter to many different types of insects, spiders, birds and mammals. Woodpeckers will often make use of the older oak trees and there are many fungi which have relationships with English oak. It has played many important roles throughout Human history such as when King Charles II hid from his pursuers within the canopy of an English oak Boscobel House. Back in the Roman times Oak was sacred to many gods including Zeus (Greek), Jupiter (Roman) and Dagda (Celtic). Druids used to practise and worship in oak groves and cherished the mistletoe that sometimes grows on oak tree branches. English oak can easily live to over 500 years old. One of the most famous English Oaks in the country is the Major Oak in Sherwood Forest - thought to be over 800 years old!