29 Interesting Secrets & Facts About Oak Trees

29 Interesting Secrets & Facts About Oak Trees

Secrets of the Wise Old Oak Trees

A familiar part of the landscape for generations as they dominate the skyline. Their distinctive shape has the presence of a kindly grandfather in parks and historic gardens. But what do you know about them? Here we go with 29 interesting facts about oak trees.

Present throughout history and arrived millions of years before humans. The first recognisable trees appeared 65 million years ago. Today there are still 600 species of oaks throughout the world–China has over 100 different varieties.

Trees in the UK

The United Kingdom is home to five species–two are natives (12,000 years since the last ice age). Three travelled here with human help.

English Oak (Quercus Robur)

The English Oak built the navy and is celebrated by the Royal Navy in the marching song–‘Hearts of oak.’ HMS victory consumed 6,000 trees in constructing her hull, masts, and other parts. This species is the most common throughout Britain and is a native tree that grows to 131 feet (ca. 40 m) in height.

English oak tree image

Sessile Oak (Quercus Petraea)

The sessile oak grows in hilly areas throughout the European Union and is Ireland and Wales national tree. It is indigenous and grows to around 131 feet (ca. 40 meters) in height.

Holm Oak (Quercus ilex)

The holm oak arrived from the Mediterranean in the 1500s and is unique among the oaks because it is evergreen. The young leaves have spines and resemble holly. Unless you are familiar with the species, you wouldn’t recognize it as an oak until the appearance of the familiar acorns.

The Romans used it for wheels–carts and chariots. It doesn’t grow as tall as the native species–half the size at 65 ft (ca. 20 meters).

Northern Red Oak (Quercus Rubra)

Unknown when this American import arrived in the UK. Perhaps it came with the grey squirrel into the parklands and gardens of the wealthy. Turning vibrant red in autumn, this one is pointy, unlike the rounded shape of the common oak, grow to 65 ft (ca. 20 meters). The English and Sessile oaks start to produce acorns at 20 years, but the northern red oak waits until 40.

Turkey Oak (Quercus cerris)

These deciduous trees arrived for ornamental plantings in the 18th Century from South-Eastern Europe and Asia Minor. They were sacred in greek mythology to gods Zeus (Jupiter) and Dagda. The leaves are a familiar curvy shape, but the acorn cups are slightly hairy compared to others. It is host to the gall wasp, which is a pest that preys on domestic oak. The maximum height is 98 feet (ca. 30 meters) midway between the local and other imported species.

interesting oak grain board

Oak Symbolism, Myth, and Lore

As well as a zodiac sign from the solar calendar, you have a tree sign from the lunar calendar. A child born in the oak month receives the blessings of generosity, nobility, honesty, and courage–along with the strength endurance of the mighty oak.

Coins featuring Oaks

The oak features on older UK coinage–the sixpence, a coin referred to in many rhymes. More recently, as the ‘O’ in the alphabet series of the pound and 10p pieces (issued in 2018). Many other countries have put them on their coins–America and Germany.

The slang name for the sixpence is ‘the tanner,’ a reference to the tanning agent in the leather industry.

New for 2020 is the €20 coin featuring oak leaves as the French symbol for happiness and liberty.

In the British Museum, you can see a gold coin featuring Emperor Augustus wearing an oak wreath. This shows how long it has played a symbolic role in human lives. If a soldier from Rome saved a civilian in battle, he received a crown of oak–the civic oak in recognition of his actions.

Postage Stamps

In 1973, the Royal Mail issued a 9p stamp featuring a one with the British trees collection. Other countries using it on postage include America–the white oak, the Soviet Union, Cyprus, Spain, and Canada (red oak).

tree of life

The Tree of Life

The tree of life is rooted in many cultures and a biblical reference. They often use it as a symbol in jewellery and paintings. A large spreading canopy and mirroring root system give a sense of majesty represented by an immense tree.

An excellent choice for the concept because it supports so many other living creatures:

  • Animals and other wildlife eat the acorns: jays, pigeons, ducks, boars, deer, bears, rats, squirrels, and mice.
  • 30 species of birds use trees for foraging and nesting.
  • 45 species of bugs make trees their home and diet.
  • 200 different associated moths.
Facts about Oak leaves and acorns

As well as the creatures that use the trees, there are the associated benefits from providing leaves for the woodland floor, shade, and shelter. Other animals eat the insects and bugs that inhabit the oak.

The oldest oak in the world is the Pechanga Great oak tree in the USA, over 2,000 years old. There are around 3,400 that class as ancient (over 400 years), with 117 aged over 800 years in Britain. The oldest in the UK are in Cheshire, Shropshire, and Lincolnshire they live for centuries.

Biblical Trees

The bible mentions oak 28 times. Examples include the ‘oaks of righteousness’ and the ‘Oaks of Bashan’ provided wood for oars. The Mamre oaks are the site of Abram’s altar to the Lord.

Plays and Stories

Making guest appearances in many books, plays, and stories, sometimes as scenery and sometimes as human symbol strength and weaknesses.

“Many strokes, though with a little axe, Hew down and fell the hardest-timber’d oak.”

Aesop’s fables compare the mighty oak to the weakness of the reed (or willow in later versions) as a moral lesson that sometimes you need to bend to survive.

Harper Lee’s book (To Kill a Mockingbird) features a character symbolizing the opposite traits of kindness and then intolerance.

Virginia Woolf (Orlando) wrote a poem about it as a central focus for her long-lived poet.

In AA Milne’s stories about Winnie the Pooh, the loveable bear finds bees (and honey) at the top of a large oak tree.

Finally, where would Robin Hood be without the oaks of Sherwood Forest?

Military and Heraldic

The leaf shows faith and endurance in heraldic terms and on a “coat of arms’ great age. The Mansfield coat of arms granted to the city on 10 June 1987 includes a tree as a reference to Sherwood Forest. The city motto is “Industry flourishes as the oak.”

The US utilize the silver and gold oak leaf to show army rank, and oak clusters appear on many medals.

Green man oak facts

Green Man

The green man or foliate heads appears among the stone and wood carvings in many churches and cathedrals. Look closely, and you see that the forest spirit includes foliage and acorns in most cases.

Oak and Its Usage

Before the industrial revolution, forests were an essential resource, and oak wood continues to supply materials for many applications today. Still, lots of use in construction for timber framing, doors, and to manufacture European oak furniture.


Herbal medicine accesses the medically beneficial components of plants. Modern medical practices use purer forms of these active ingredients. Before the rise of the pharmaceutical industry, trial and error identified valuable drugs from nature.

Bruised leaves applied to wounds was a remedy utilised by Galen of Pergamon, a doctor in the Roman Empire.

Bark substitutes for quinine, and in herbal medicine, it has the properties of a tonic, astringent and antiseptic. Waters or alcohol extracts useful chemical compounds. The use relates to dysentery and bleeding.

Acorns and bark steeped in the milk provide an antidote to ingesting poisonous herbs and medicines.


The high level of tannic acid means large quantities are toxic to dogs, horses, cattle, goats, and sheep and cause kidney damage gastroenteritis. But the acorn crops are an excellent food for pigs and were harvested for that purpose. Free-range boars and swine rooting about in woodlands fatten on fallen acorns.

Providing protein, carbohydrate, and healthy unsaturated fats. They are also rich in potassium, manganese, calcium, phosphorus, and niacin. They contain plenty of valuable nutrients but seldom appear on the human menu. There is no profit in selling them, and the taste is bitter. Bitter foods are better for health, but most people avoid bitter tastes in favour of sweet.

You can grind acorns to flour or roast and grind as a coffee substitute. They tasted bitter, but in hungry periods, the acorn nourishes if properly processed to leach out some tannic acid by soaking in water.

You can use acorn flour the same way as wheat flour, but not for bread making as it is gluten-free.

The roots have a symbiotic relationship with the black Périgord truffle, one of the most expensive foodstuffs. You can’t plant truffles; you need to grow an oak and hope for the best.

Colours from the Tree

Various techniques extract dye from plants. Different plants, leaves, fruits, and stems yield unique colours. The tannin means that oak dyes don’t need a mordant to fix the dye to the fibre.

Oak galls yield greys and blacks for dyed stuff.

The Aleppo oak gall started the ink industry as it has a high concentration of wasp larvae. The ground galls provide a deep black ink.

Leather Production

Oak bark is abundant in tannins, and this property allows it to tan hides into leather. The process takes twelve months or more. Traditional tanning produces excellent high-quality leather and still used today for premium leather products.

Interesting Oak Corks

Bottle Stoppers

The tree of Portugal is the cork oak, and Portugal is the source of 55% of natural cork. They contribute massively to the economies of seven countries in the EU involved with cork harvesting.


Swill baskets are a traditional craft still practised in the Lake District. Coppiced oak and hazel combine to make a hard-wearing basket used in industry, agriculture, and domestic purposes.

The trunks 4-6 inches (15.24 cm) turn into thin pliable ribbons that weave around flexible hazel sticks. The process involves cleaving and soaking.

Houses and Ships

Oak wood is famed for its capacity in constructing buildings (Houses of Westminster and Tudor homes) and ships (Vikings longboats and Tudor warships). Quarter sawn boards even more desirable for the distinctive medullary rays. The high tannin content makes it resistant to insect attack and mould.

Interesting Oak Treen


Treen–of the tree is an all-purpose term for any item made from wood, not a ship, piece of furniture, or house. Oak treen covers knickknacks, jewelry, and other small functional or decorative items.

Wooden oak items can be created by carving and turning. Oak has a reputation for being difficult to work due to the fibrous grain. In the hands of a skilled craftsman, the bowls, pens, and carvings are exquisite and tactile objects.

Oak Whiskey Barrels

Oak Barrels

Oak is a useful and practical material for making wine barrels, but it adds a richness of flavour, including smokey, vanilla, and oaky.

Oak in wine can add three principal benefits:

Additional flavour notes.

  • Slow addition of oxygen–decreases astringency and improves smoothness.
  • Provides condition for malolactic fermentation–a process that produces a creamier tasting wine.

Oak vats provide the following flavour compounds:

  1. Syringaldehyde–like vanilla.Oak lactone–herb flavours like dill, woody notes, and a hint of coconut.
  2. Eugenol–think smokey spices and cloves.
  3. Guaiacol–a hint of burnt toffee.
  4. Furfural–burnt caramel, bitter almond and dried fruit.

Not only does it improve whisky (whiskey, bourbon, brandy), but they are essential to produce colour and a distinctive flavour. Whisky is an alchemist’s brew of water, alcohol, and oak. For whisky casks, oak is seasoned (dried), toasted and charred–the exact degree of each is part of the whiskey makers art.

Whisky barrels may pass on to the wine industry or on for other applications. At this stage, the barrel may be 50-60 years old. Wood is still useful for–barbecue smoking chips, barrel planters, and woodcraft using the staves. The timber is still fit for purpose and can turn into practical oak gifts like bottle openers or pens.

Farewell to the Oak

The UK contains around 121 million oak trees. These are both iconic and treasured because of their role in promoting biodiversity and their many uses. From leather to whisky production to providing shade and clean air in the park.

Producing 2,000 to 9,000 acorns a year. But only one in 10,000 has the possibility of growing and taking decades, if not hundreds of years, to mature. When you plant an oak, you are planting for the next generation, not for yourself. If you have any other interesting facts, message me below.

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