Complex sentence: The area encompasses about 4,000 acres (16 km²) of rolling hills, with approximately 1,000 of these acres (4 km²) set aside as parks, recreation areas, and open space.
Split into simpler sentences: The area encompasses about 4,000 acres (16 km²). About 1,000 acres (4 km²) are set aside as parks, recreation areas and open space.