Damien Raffa: A Brief History of the Presidio

Wild Presidio: The Original Landscape

Approximately 15,000 years ago, natural forces completely reshaped the area we now know as San Francisco Bay. The sea level rose due to glacial melting. Rising waters formed the bay, and the coastline receded from its former location out at Farrallon Islands. At the tip of the long peninsula we now know as the Presidio, ancient sands migrated to form a new border between land and sea.

On that peninsula of long ago, plants and animals continued to evolve together year after year. Bald eagles and giant condors glided through the air. Mountain lions, bobcats, coyotes and wolf packs stalked from the dunes to the prairies to hunt jackrabbits, elk and deer. Grizzly bears fed on blackberries and lumbered along the north and west shores now called Baker Beach and Crissy Field.

Most of the Presidio was then "central dune scrub" habitat. It was part of an extensive sand dune system that covered almost 14 square miles. This system stretched from what is now Daly City in the south to Crissy Field, and as far east as the Financial District of San Francisco, making it one of the most extensive dune areas on the Pacific Coast of North America.

The Human Element

The first humans set foot on the Presidio at least 5,000 years ago.

Because the land provided ample food and fresh water, by around 700 A.D. groups of Ohlone Indians were using the land along the marsh system that included the Crissy Field area.

The Ohlone's most dramatic form of ecological management was their annual practice of burning back the landscape. Fires were set each year to limit the density of oak woodlands and the extent of brushlands, stimulate growth of seed-producing plants, promote green plant growth to feed herbivores, facilitate growth of plants used for basketry, and open land for easier hunting.

The Spanish arrived and founded the Presidio as a military outpost in 1776. When they first set foot on the land, the Main Post looked much like the valleys of the Marin headlands do today.

The Spanish likely chose this site because of the clear bay view to the north and the open areas that could be used for grazing the animals they brought with them. The site was also accessible to the harbor entrance, which they intended to fortify, yet it was somewhat sheltered from the wind.

Spanish and Mexican occupation of the Presidio had a strong impact upon both the Ohlone culture and on the area's native ecosystems. Areas of natural habitat were cleared to make room for food crops.

In addition to hunting native animals, the Spanish brought horses, cattle, sheep and goats that grazed in areas around the Presidio and greater San Francisco, then called Yerba Buena after a native plant that still grows in the nooks and crannies of the Presidio.

During the Presidio's 66-year habitation by Spain and Mexico, almost all of its oak woodlands were cut down for buildings and firewood. New grazing lands were acquired to the south after cattle overgrazed Presidio lands.

The next major chapter of human history at the Presidio began with the arrival of the U.S. Army, whose tenure lasted 146 years. During this period, the Main Post was steadily transformed by successive waves of building, demolition and re-building, which resulted in its current mix of architectural styles. Interestingly, only 100 years ago the Main Post was still the largest "built environment" on the Presidio, with the rest of the area remaining undeveloped, albeit radically altered by continued grazing, farming and military exercises that began with the Spanish.

Another major transformation of the Presidio landscape began in the late 19th century with the planting of forests. This tree planting effort was the most ambitious landscaping project the Army had ever undertaken. Influenced by an urban parks movement, the forest stands were intended to distinguish the Presidio from the rest of the City, give depth to the landscape and serve as a windbreak.

Much of the forestation of the Presidio took place over a 40-year period.

The existing Presidio-wide network of roads and buildings were fully developed in the 20th century.

A New Chapter of Natural and Cultural History

In 1994 the Presidio began its transformation from military post to national park. The National Park Service and Presidio Trust have joined forces to preserve and enhance the natural and cultural resources that remain a vital part of the place.

Like the 384 other national parks throughout the United States, the natural areas and historic features of the Presidio are considered special resources that need to be managed with care. Thus, the new chapter of human history now being written here might best be described as one of stewardship.

In spite of its urban landscape, there are more than 450 native plant and animal species living within the Presidio. A natural resources program currently manages approximately 200 acres around the park, with habitats including central coast scrub (North Baker Beach), arroyo willow forest (Mountain Lake area), serpentine bunchgrass (Inspiration Point), and tidal salt marsh (Crissy Field), among others.

Rebuilding the intricate ecological framework of the Presidio's once vast natural systems, while respecting the significant evidence of human intervention, will require continued human involvement.

The work to restore and maintain the Presidio's ancient native habitats has largely been accomplished by volunteers from schools, organizations and the broader community. Their dedicated efforts include seed collecting and propagating seedlings at the native plant nursery, replanting young plants at the restoration sites, weeding out non-native invasive plants, helping protect animals such as the California quail, and monitoring the results of ongoing restoration efforts.

With continuing stewardship, the Presidio will be protected and preserved for the future.

Damien Raffa is the Natural Resources Specialist at the Presidio Trust.