29 Interesting Secrets & Facts About Oak Trees

29 Interesting Secrets & Facts About Oak Trees

Secrets of Wise Old Oak Trees

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

Present throughout history, arriving 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.

Paperbark Maple: Understory tree wi...
Paperbark Maple: Understory tree with year-round interest

UK Trees

Great Britain 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)

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 type is most common throughout Britain, a native tree that grows to 131 feet (ca. 40 m) tall.

English oak tree image

Sessile Oak (Quercus Petraea)

Sessile oak grows in hilly areas throughout the European Union and is Ireland and Wales national tree. It is indigenous, rising to around 131 feet (ca. 40 m) high.

Holm Oak (Quercus ilex)

Holm oak arrived from the Mediterranean in the 1500s and is unique among oaks because it is evergreen. Young leaves have spines that resemble holly. Unless you’re familiar with the oak species, most wouldn’t recognize it until the appearance of its familiar acorns.

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

Northern Red Oak (Quercus Rubra)

Unknown when this American import arrived in the United Kingdom. Perhaps it came with the grey squirrel into parklands, gardens of wealthy landowners. Turning vibrant red in autumn, this one is pointy, unlike the rounded shape of common oak, growing to 65 ft (ca. 20 m). English and Sessile produce acorns at 20 yrs, but northern red oak waits until 40.

Turkey Oak (Quercus cerris)

These deciduous trees arrived as 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. Leaves are a familiar curvy shape, but acorn cups are slightly hairy compared to others. It is host to the gall wasp, a pest that preys on domestic oak. Maximum height is 98 feet (ca. 30 meters) midway between local and other imported species.

interesting oak grain board

Symbolism, Myth, and Lore

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

Coins featuring Oaks

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

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

New in 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 to recognise his actions.

Postage Stamps

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

tree of life

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 sizeable spreading canopy and mirroring root system give a sense of majesty represented by an immense tree.

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

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

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

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 28 examples. These 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, sometimes as human symbol strength or weaknesses.

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

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

Harper Lee’s book (To Kill a Mockingbird) features a character symbolizing opposite traits of kindness 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, a loveable bear finds bees (and honey) at the top of a large oak tree.

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

Military and Heraldic

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

The US utilize a silver or gold oak leaf to show army rank; also, oak clusters appear on many medals.

Green man oak facts

Green Man

Foliate heads or green man appear among carvings in many churches and cathedrals. Look closely; you will see the forest spirit includes foliage and acorns in most cases.

Oakwood Usage

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


Herbal medicine accesses medically beneficial components of plants. Modern medical practices use purer forms of these active ingredients. Before the rise of pharmaceutical industries, 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; in herbal medicine, it has properties of a tonic, astringent and antiseptic. Waters or alcohol extracts beneficial chemical compounds. Usage relates to dysentery and bleeding.

Acorns or bark steeped in milk provides an antidote to ingesting poisonous herbs or medicines.


A high level of tannic acid means large quantities are toxic to dogs, horses, cattle, goats, sheep, causing kidney damage gastroenteritis. But 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, carbohydrates, and healthy unsaturated fats. Also rich in potassium, manganese, calcium, phosphorus, and niacin. They contain plenty of valuable nutrients but seldom appear on our human menu. There is no profit in selling them; they also taste 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, then grind as a coffee substitute. They tasted bitter, but in hungry periods, they nourish if properly processed to leach out some tannic acid by soaking in water.

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

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, fruits, and stems yield unique colours. The tannin means that oak dyes don’t need a mordant to fix the dye to 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. Ground galls provide a deep black ink.

Leather Production

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

Interesting Oak Corks

Bottle Stoppers

The tree of Portugal is the cork oak; Portugal is the source of 55% of natural cork. They contribute massively to 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.

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

Houses and Boats

Oak wood is famed for its capacity in constructing buildings (Houses of Westminster, Tudor homes), ships (Vikings longboats, Tudor warships). Quartersawn boards are even more desirable for their 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. Treen covers knickknacks, jewellery, 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 its fibrous grain. In the hands of a skilled craftsman, bowls, pens, carvings are exquisite and tactile objects.

Oak Whiskey Barrels

Barrel Making

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

In alcohol it can add three principal benefits:

Additional flavour notes.

  • Slow addition of oxygen–decreases astringency and improves smoothness.
  • Provides condition for malolactic fermentation, which creates a creamier taste.

Oak vats provide these flavour compounds:

  1. Syringaldehyde–like vanilla. Oak lactone–herb flavours like dill, woody notes, with 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 it is essential to produce colour and a distinctive flavour. Whisky is an alchemist’s brew of water, alcohol, and oak. For whisky casks, it 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 other applications. At this stage, the barrel may be 50-60 yrs old, though still useful –barbecue smoking chips, barrel planters, woodcraft using recycled staves. 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. 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 town parks.

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

Leave a Comment

Your email address will not be published. Required fields are marked *