Green Tree Park occupies land once known as Johnston Hollow, a low area between the higher hills of Westwood, Mount Washington, Banksville, and the ridge of Greentree Road, where before 1950 much of the ground lay about 150 feet below the present Parkway Interchange. Beginning in 1950 and continuing until about 1994, approximately 24 acres were filled with an estimated 2.8 million cubic yards of rock, wood, brick, masonry, paper, metal, dirt, and other debris from many sources, creating what became known as the Suella Landfill, also called Suella Park, Suella Hollow, Suella Valley, Suella Area, and Suella Dump. The filled area included Suella Drive, later relocated somewhat for Parkway interchange construction, and nearby stood West's Store at Greentree Road and Mansfield Avenue until it was demolished for the Parkway, completed in 1952. Bill Lewis recalled the first trucks bringing dirt from the West End By-Pass to fill the valley of Johnston farm, hauling night and day for months. Rubble from many Pittsburgh-area demolition and excavation projects was brought here, including a large 1958 fill from Gateway Center #4, as well as material from One Oliver Plaza, the United States Steel Building, Forbes Field, the Sears structure on the North Side, razed houses, parking lots, and Banksville Road resurfacing, using alternating layers of debris and dirt in the trench method. The area had earlier been part of the Johnston property, where Mary Johnston's eighteen-room house, built in 1895 and occupied until about 1952, stood near the present interchange amid an apple orchard, vegetable gardens, and white turkeys. Between the 1930s and 1950s, three homes stood on Suella Drive, named for Suella Anwyll, and several families lived there while other nearby owners held property in the fill area. Various future uses were considered while the land was being filled, including a Borough Building, but by the early 1970s it was clearly understood as a planned park area. Green Tree Park was formally named in 2002, though the name had been chosen in 1965, and the borough later acquired the Keystone Oaks School District portion in 2018. The 30.25-acre park is now a recreational complex with walking track, ball fields, school fields, a street hockey rink, soccer fields, a dog park, community event space, and support facilities, representing the transformation of an unusable tract into a major public recreation area.