Oak tree as British symbol

The history
The term Royal Oak:
is used to denote the escape of King Charles II from the grasps of the parliamentarians after his father's execution
is a symbol of England, representing strength and endurance
Charles II of England when Prince of Wales

Traditions
Oak Apple Day or Royal Oak Day was a holiday celebrated in England on 29 May to commemorate the restoration of the English monarchy, in May 1660. In some parts of the country, the day was also known as Shick-Shack Day or Arbour Day.

Traditions
"Heart of Oak" is the official march of the Royal Navy of the United Kingdom. It is also the official march of the Canadian Navy, as well as the Canadian Forces' Naval Operations Branch.
The chorus:
Heart of oak are our ships, jolly tars are our men,
we always are ready; Steady, boys, steady!
We'll fight and we'll conquer again and again.

1987: Oak tree in a coronet, representing England.
Edge inscription: DECUS ET TUTAMEN.

In 2000, Son of Royal Oak was badly injured during a violent storm and lost many branches. Another oak sapling was planted near the site of the original Royal Oak in 2001 by Prince Charles.
In commemoration of the tree's significance in British history a number of places and things have been named after the Royal Oak. The Royal Oak is the third most common pub name in Britain.

Pubs
Crown (704)
Red Lion (668)
Royal Oak (541)
Swan (451)
White Hart (431)
Railway (420)
Plough (413)
White Horse (379)
Bell (378)
New Inn (372)

Royal Oak Pub in Windsor
Pubs

Charles I's son hides in an oak tree. Pub sign.
Doorway of the Royal Oak public House, Lozells Road, Lozells, Birmingham, England.