Naturalistic or...
Many of the early public parks were built in burgeoning cities as a means of dealing with the pressures of urbanization and industrialization. Land was already becoming scarce and expensive and the expanses affordable and available for park development were often not attractive for other uses—swamps, marshes, ravines, and the like. Not naturally picturesque, they required manipulation to become the scenic pastoral settings toward which early park planners strove.
Planners would manipulate the existing environment to create more pleasing settings, doing things like dredging marshes and swamps to create lakes or grading the land to create rolling meadows. In New York's Central Park, more gunpowder was used blasting rocky ridges to change the topography than was later used in the entire Battle of Gettysburg.
The eventual effect of the picturesque landscape, secluded walks, and sheltering trees and shrubs was to stand in contrast with the bustling, crowded city from which the park was to provide respite.