Complex sentence: During the early part of the 19th century, logging was the principal commercial activity in the area; as much as 50 million board feet (120,000 m³) of lumber were produced annually.
Split into simpler sentences: During the early part of the 19th century, logging was the principal commercial activity in the area. It produced as much as 50 million board feet (120,000 m³) of lumber were produced annually.