text: In 1847, a speech by George Perkins Marsh called attention to negative human impacts such as deforestation. Marsh later wrote Man and Nature in 1864 based on his idea for conserving forests. Around the same time, Henry David Thoreau’s Walden of 1860 discussed preservation of nature and applied these ideas to urban planning saying, “I think every town should have a park,” and stated the “importance of preserving some portions of nature herself unimpaired.” Frederick Law Olmsted, a landscape architect, agreed with these ideas and planned many parks, areas of preserved land, and scenic roads, and in 1887, The Emerald Necklace of Boston, MA. The Emerald Necklace is a system of public parks linked by parkways that serves as a home to diverse wildlife and provides environmental benefits such as flood protection and water storage.
  In Europe, Ebenezer Howard led the garden city movement to balance development with nature. He planned agricultural greenbelts and wide, radiating boulevards surrounded by trees and shrubbery for Victoria, England. One of Howard's concepts was of the "marriage of town and country" to promote sustainable relationships between human society and nature through the planning of garden cities.
  The US government became more involved in conservation and land preservation in the late 1800s. This was seen in the 1864 legislation to preserve the Yosemite Valley as a California public park, and 8 years later, the United States’ first national park.