For example, Tocal College received both the Sulman and Blacket medals in 1965 and is credited with firmly establishing the Sydney School idiom: "Expressive structural use of robust and enduring materials seamlessly integrated within its landscape setting was a groundbreaking approach to institutional design." Meanwhile, public attitudes to the urban environment began to change; by the 1960s and 1970s the environmental movement was on the rise. The publication of Rachel Carson's influential book Silent Spring in 1962, the rise of environmental organisation Greenpeace, reaction in Tasmania to the Lake Pedder and Franklin Dam projects and the rise of the Tasmanian Greens political party were all indicators of the greater public awareness of the natural environment. The use of local plant species in private gardens was being popularised by Thistle Harris in her book Australian Plants for the Garden (1953); Betty Maloney and Jean Walker's books Designing Bush Gardens (1966) and More About Bush Gardens (1967) and Ellis Stones in her book Australian Garden Design (1971). Likewise landscape practitioners like Bruce Mackenzie rejected the traditional design of urban parks which used introduced plants and formal spaces. Bruce Mackenzie describes this new way of thinking as a "respect for a spirit of place, the land, the genus loci." Landscape architects began responding directly to the immediate site as well as having an appreciation of the broader landscape. The movement took on the name "Sydney Bush School". Mackenzie describes the impact and the essential elements of his Sydney Harbour Park designs: "Sydney Harbour Parks turned out to be a somewhat ground breaking realisation using local materials in a direct response to the immediate environment and the elements of the harbour landscape. The ideas had been developing in previous years with prior experience at Commodore Heights, Ku-ring-gai Chase National Park, and then current involvement with Sydney Kingsford Smith International Airport (not documented). "Plant species, sandstone walls and cliff faces, wharf poles and jetties, combined to be so evocative of the harbour's sense of place. Assembled together in a way that had not been done before, recreating the charms of the Sydney natural bush and sandstone, much-loved harbour side places and childhood bush playgrounds. Another important aspect was that the flow of landscape design responded to the informal thrusts of the existing site, to its vague shapes and levels. "Human patterns of usage - paths and walks, lookouts, picnic areas and car parks touched a