Forests of the United States
It has been estimated that before European settlement, forests in the United States mainland covered nearly 1 billion acres (4,000,000 km2). Since the mid-1600s, about 300 million acres (1,200,000 km2) of forest have been cleared, primarily for agriculture during the 19th century.
Source: Wikipedia — Forests of the United States (CC BY-SA 4.0)