The English and Durmast oaks are two of our 32 native species of tree. These are the trees which came here before the sea swept through the straits of Dover and cut Britain off from Europe around 7,500 years ago.

Alongside the two native oak species, there are many later introductions. The evergreen Holm Oak (Quercus ilex), called after an old English name for a holly bush, was introduced from the Mediterranean in the 16th century. The Turkey oak (Quercus cerris), with its orange fissured bark, was brought here in around 1735, and can now be found in many parks. The Luccombe oak (Quercus Hispanica), a cross between a Turkey and a Cork oak, is named after the Exeter nurseryman who discovered it in the 1760s. Luccombe used its timber to provide wood for his coffin, which he kept under his bed until his death at the age of 102.

From catkins to acorns

In May, the oak produces pale green male flowers, called catkins, whose pollen is blown by the wind to fertilise the less conspicuous female flowers. These develop into the characteristic acorns - called after the Anglo-Saxon name for oak - ac, and corn, meaning seed. The acorn crop is also called "mast'", related to meat, because it provides excellent food for pigs in winter. A heavy acorn crop, which occurs irregularly, is known as a "mast year".

Mighty trees

Long-lived oaks can grow to an enormous size. The largest recorded was the Newland Oak, whose trunk was an amazing 45ft across. When it collapsed in 1955, it would have been more than 1,000 years old. One of the biggest surviving trees  is the 33ft-wide Major Oak in Sherwood Forest, popularly thought to be Robin Hood's headquarters. Read more about Robin Hood and his Merry men here.

Charcoal burners

Apart from its desirability as a building material, the most important use of oak was to make charcoal. This can give about twice the heat as an equivalent weight of wood, and it was very important for the iron-smelting industry based in the Weald of Kent and Sussex.

Charcoal was made by the controlled burning of lengths of oak, called cords, in a kiln - a stack of cords covered with thatch and earth. This had to be watched carefully for up to three days while the burning continued. The burners lived in the forest, and their lonely lives have inspired poems and folk-tales. In Now We Are Six (1927), AA Milne has a lyrical poem describing the peaceful life of a charcoal burner:

The charcoal burner has tales to tell.
He lives in the forest, alone in the forest,
He sits in the forest, alone in the forest,
And rabbits come up and they give him good morning,
And rabbits come up and say, 'Beautiful morning',
And the moon swings clear of the tall black trees,
And owls fly over and wish him good night.
Quietly over to wish him good night.

Ink from oak trees

A less familiar use of oak was making black ink from its galls - the ball-like tumours formed by wasps laying eggs in oak buds. These were ground up and boiled in white wine or vinegar. According to a recipe of 1619, the boiling lasted as long as it took to say the Lord's Prayer three times. This was then mixed with copperas (made by pouring sulphuric acid over old nails) and gum arabic.

Shrinking forests

The last 2,000 years have seen a steady decline in the size of the oak forests which once covered much of England. In 1608, King James I carried out a survey of the royal forests, and found that 350,000 trees were available, less than half of them fit for ship-building. By the 1780s, these reserves had fallen by four-fifths. As a result, ship-builders in the 19th century were forced to use inferior timbers. In 1810, one warship, the Queen Charlotte, had to be completely reconstructed just a year after launching, due to dry rot.

In 1919, after an acute timber shortage during the first world war, the Forestry Commission was set up to protect and expand Britain's woods. The Commission has planted many new forests, and also helps private landowners regenerate their woods. The oaks are slowly coming back.

Find out about the work of the Forestry Commission here