Coastal California is made up of either Redwood forest or what is basically a desert nicely cooled by fogs from the Pacific. The non-forested portion of the California landscape had little to offer the eye beyond a modest variety of native weeds, and European settlers got right to work planting trees and flowers.
Today, the cult of extreme Environmentalism flourishes the length of the left coast, and purists in California have come to regard non-native Holland grass (originally planted to keep the sand dunes from eroding), Eucalyptus, wild rose and other non-native trees, plants, and shrubs as sacrilegious human affronts to Mother Nature’s original perfection.
San Francisco is going to spend a lot of money deliberately de-foresting the Presidio and other parks.
While in Southern California, botanical vigilantism is being prosecuted.