• wilderness
• farmland
• swamps
• unbuilt land that trees grow up on
  

spaces like marshes and steep hillsides that had previously been left undeveloped were now being used for housing developments as well
older neighborhoods often had parks but the new subdivisions usually did not

Three arguments:

conservation

• is it bad policy to turn so much prime farmland into housing developments?
• woodlands and swamps played a key role in soaking up rain to prevent flooding
  

• some of this came from a broader attack on mass culture
• subdivisions needed open space to make them more attractive and give a sense of place

• providing recreational areas would help children grow up healthy
• children often played in undeveloped land until it to was developed

William Whyte was a key advocate for open space, with practical suggestions

• conservation easements
• changing zoning rules to allow cluster developments

other ideas

• land banks
• local government-owned open spaces and outdoor recreation
• but it was too expensive for local governments to buy enough land to keep up with development
• the price of land went up because more and more people wanted suburban houses not too far from the city
  

What worked at least in some areas:

• environmental arguments such as preserving wetlands
• arguments for more regulation to protect the land as a resource
• when open space was saved for recreation then other kinds of pollution became more obvious as a problem
• the 1960s were a time when population growth became a concern
• wilderness organizations like the Sierra Club shifted their concerns only slowly
• Audubon became a key organization working for open space preservation
• arguments about environmental responsibility grew more common