Departing slightly from the usual approach of this column, I’d like to introduce you to a familiar yet unexplored feature of the Bay, Yerba Buena Island (YBI). It is rare indeed, in the midst of this megalopolis, to have an opportunity to botanize on a piece of land that was entirely overlooked by our earliest botanical explorers and those who followed. Because it was under military control, YBI could not be surveyed for the 1958 flora of San Francisco by Howell, Raven, and Rubtzoff, so it was not included in that publication. This article will present an introduction to the post-colonial history of YBI. Part two (in June) will discuss some of the more interesting botanical resources still to be found there. I would have loved to tell this story sooner, but the Navy made me wait until its reports went public.

In 1996 I was asked to conduct rare plant surveys and vegetation mapping on YBI as part of a base closure study. I was skeptical about finding anything of interest. As seen from the Bay Bridge, dense stands of eucalyptus and French broom seem to dominate the island’s steep slopes. I was very surprised and thrilled to discover that YBI still supports a high diversity of native plant species and relicts of natural plant communities. The flora of YBI offers an exciting glimpse into the past, providing us with a hint of how the island looked prior to colonization. Now that 75% of the island belongs to the city, we have an unprecedented opportunity (and responsibility) to study, preserve, and enhance some of the best (and in some cases, the last) examples of the northern peninsula’s natural heritage.

YBI is a natural geologic feature (unlike the man-made Treasure Island) of approximately 150 acres situated in San Francisco Bay. It is the southernmost of three Bay islands, including Angel Island to the north and Alcatraz to the northwest. Originally named Isla de Alcatraces (Pelican Island) in 1775 by Juan Manuel de Ayala, it was renamed Yerba Buena Island in 1826 by the English cartographer Captain Frederick W. Beechey, when he misread the Spanish maps and applied the original name to what is now called Alcatraz. YBI’s name (like our chapter’s) comes from the fragrant mint Satureja douglasii, which no longer occurs there. Between 1837 and 1850, YBI was called Goat Island after the goats that were grazed there to supply ships’ crews with fresh meat. In 1895, the name Goat Island was officially adopted by the U. S. Geographic Board, but pressure from the Native Daughters of the Golden West caused it to be changed back to Yerba Buena Island in 1931. Other unofficial names have included Wood Island (named for the wood, presumably coast live oak, Quercus agrifolia, that was cut and supplied to sailing vessels, not for this author, who came much later); Sea Bird Island; Spear’s Island, after Nathan Spear, the man who brought goats to the island and claimed ownership from 1835 and 1849; and Treasure Island, for the rumors of treasure buried there. The only treasure ever buried there was smuggled opium.

YBI has a long history of human disturbance. Following colonization by Europeans, grazing by free-roaming goat herds and harvesting of native oak woodlands resulted in the virtual deforestation of the island. During the period of private ownership from 1835 to 1867, several buildings were constructed, including a barn, stable, windmill, carpenter’s shop, forge, and wharf. Oyster beds were farmed off the eastern side of YBI and a quarry was established to supply building stone for San Francisco and ballast for ships. In 1867 the Army established a base there and (illegally) assumed complete control of the island. There were many lawsuits, but the Army prevailed. The Navy assumed control of the island in 1898.

In 1887, the military began planting trees on the island as part of California’s first Arbor Day. While most of these plantings on the ridge and hilltop were killed by harsh weather and fire, some of the trees planted at lower elevations are believed to have survived to this day. The Navy established a training station and built barracks for 500 men in the eastern cove. World War I prompted a major building project on YBI, canvas tents were erected at the eastern end, and the facility’s personnel reached 13,000 during the war. In 1923, due to overcrowding, all naval training facilities on Mare Island and YBI were transferred to San Diego. Construction of the Bay Bridge was completed in 1936 (during which time a mastodon tusk was found), after which the Navy constructed Treasure Island (TI) which once again led to an increase of activity on YBI.

During World War II YBI functioned as a Receiving Ship for transfer of men to ships and bases, processing an average of 1,500 men per day. As the island became overcrowded, the function was transferred to Treasure Island in 1946. After World War II the Coast Guard became the primary tenant of the eastern side of YBI. In 1966, apartment-style officers’ quarters were constructed on the north and west slopes.

YBI had two Native American burial sites and three colonial burial areas, none of which remain today. One Indian burial site was originally located near the summit of the island where the signal tower is now, and the second was situated in the eastern cove. Native American remains were excavated by U.C. Berkeley anthropologist Dr. E. W. Gifford. A colonial cemetery was established in 1849 near the western end of Macalla Road near TI Road. It was relocated to the Presidio in 1938, prior to the opening of the Golden Gate International Exposition; Expo officials didn’t want visitors to have to drive by a depressing cemetery.