Tree of Liberty: A tree set up by the people, hung with flags and devices, and crowned with a cap of liberty. The Americans of the United States planted poplars and other trees during the war of independence, "as symbols of growing freedom." The Jacobins in Paris planted their first tree of liberty in 1790. The symbols used in France to decorate their trees of liberty were tricoloured ribbons, circles to indicate unity, triangles to signify equality, and a cap of liberty. Trees of liberty were planted by the Italians in the revolution of 1848.
Source: The Dictionary of Phrase and Fable, 1894
Contributed by: Zaady