In 1772, the colonists had no right to trees over 12" thick, not even if it was in their front yard.
A law reserved every white pine that size for the Royal Navy's masts. Surveyors roamed New Hampshire slashing a mark into the trees, claiming them for the King of England.
The mill owners of Weare ignored the law and cut the trees they wanted to. So the sheriff rode out to arrest them and collect the fines.
The Weare men blackened their faces and went after the sheriff in what is now called the Pine Tree Riot. They gave him a lash for every tree he'd charged them for. Then they cropped the ears and tails off his horses and sent him riding out of town through a jeering crowd.
Before the Boston Tea Party and the Boston Massacre, a New Hampshire town defied the Crown.
And the pine tree symbol remained. When Washington needed a flag for his first warships in 1775, he put a New England pine on it, over the words "An Appeal to Heaven."
This turned something that the King used to tyrannize the colonists to support his Navy, into a symbol of a country defying him on their own Navy.