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Santos, M.J., A. Peers, A. Avery, E. Francis, E. Steiner and J. Coolidge. 2014. Conservation histories of California: The San Francisco Bay Area. Spatial History Project. Originally published as part of the 2013 CESTA Anthology.
Conservation Histories of California

The San Francisco Bay Area
Maria J. Santos 1 & Alexandra Peers 2 & Alice Avery 3 & Emily Francis 4 & Erik Steiner 5 & Jake Coolidge 6
1. Spatial History Project, Center for Spatial and Textual Analysis; and the Bill Lane Center for the American West; Stanford University
2. Research Assistant, Spatial History Project
3. Research Assistant, Spatial History Project
4. Research Assistant, Spatial History Project
5. Creative Director, Spatial History Project
6. Geospatial Historian, Spatial History Project
"The idea of nature contains, though often unnoticed, an extraordinary amount of human history1."

In 1864, Abraham Lincoln granted 20,000 acres of land to the State of California, land that would become Yosemite National Park and the Mariposa Big Tree Grove. In the 1880s, the state made initial steps to impose limits on the logging of its forests. In the 1930s, U.S. Forest Service scientist Albert Wieslander painstakingly documented California forest resources and plant species, leading to their eventual inclusion on a list of threatened and endangered species. Urban sprawl in the latter half of the 20th century prompted communities to secure open space amenities close to residential areas. All of these seemingly disparate actions have, in concert with hundreds of other actions over the past century and a half, shaped the current health and condition of California’s ecosystems2. Today, fully one quarter of all land in California is protected in some form or another, but our knowledge of how this came to be is fragmentary. Conservation history describes the processes that created today’s parks, preserves, and refuges, and entails both a spatial and temporal depiction of conservation activities, implementation, and achievement. Here we seek to contribute to the emerging field of conservation history3 by examining the acquisition of California’s protected lands, dating back to the 1860s. No one perspective or narrative is sufficient to encapsulate this history. As a result, the work presented here integrates several histories developed by multiple researchers on the Reconstructing California Conservation History team focusing on a restricted geographic location in the state -- The San Francisco Bay Area. The San Francisco Bay Area is reviewed in some detail, linking the timeline for conservation land acquisition to changes in land cover, urban development, and road construction. Focus then shifts to the Bay Area’s iconic tree, the redwood (Sequoia sempervirens), claimed first for timber and subsequently for conservation. Finally, the mitigating influence of conservation lands on local climate change effects points to their increasing value in the years to come.
First the mountains, second the ocean at last the desert: 
Shifting priorities over 150 years of land conservation
California is arguably the state that has led the implementation of forest reserves. Since the granting of Yosemite Valley and the Mariposa Big Tree Grove in 1864, much effort has been put forward by multiple individuals, institutions, and agencies to protect and preserve the state’s remarkable biodiversity. Efforts by the State of California officially started as early as 1927, when it created the State Parks Commission and in the following year gave Frederick Law Olmsted Jr. a mandate “to make a survey to determine what lands are suitable and desirable for the ultimate development of a comprehensive, well-balanced state park system, and to define the relation of such a system to other means of conserving and utilizing the scenic and recreational resources of the state”4. Guided by local awareness of the need for acquiring conservation land, the state subsequently created special legal provisioning and agencies for this purpose. Special districts were created in the 1940s, and county parks in the 1960s. The Williamson Act of 1967 allows the state to negotiate directly with land owners to propose a tax break for their lands in exchange for their persistence as agriculture open space, and conservation easements have been created from the 1980s onward.
The visualization History of Land Acquisition for Conservation depicts a first reconstruction of California’s conservation history—the timeline of land acquisition for conservation (see below). California is not only one of the most biodiverse areas in the United States, the California Floristic Province is one of the world’s 25 most diverse areas on the planet5. Forty four percent of the earth’s plants and 35% of the earth’s terrestrial vertebrates are found only in these 25 hotspots, despite the fact these hotspots make up just 1.4% of the world’s land surface5. For California itself, 44% of its plant and vertebrate species are endemic to the state6. These biodiversity hotspots have immense implications for conservation strategies, as their conservation can protect large numbers of species living in relatively small areas, while at the same time, these lands are gravely threatened by changes in land cover and perhaps climate change.
History of Land Acquisition for Conservation
Depiction of the timeline of land acquisition for conservation, with corresponding data on threatened and endangered species observations over time.
The peak of land acquisition in California occurred at the turn of the 20th century. At this time, the National Park Service and the Forest Service acquired large tracts of federal land, as for example what was to become Yosemite National Park. The 1930’s peak of land acquisition corresponds to California State Parks acquisitions and the 1980’s to federal land acquisition. Generally mountainous areas were acquired first, followed by the acquisition of state beaches, and most recently desert lands.
The Yosemite Valley was the first area designated as a state forest reserve on June 30th 1864 by the president Abraham Lincoln. Soon after the designation of Yellowstone as the first National Park, Yosemite became the first National Park in California in 1890. Photo by Maria J. Santos, 2011.
Conservation for the Land or for the Species? Tracking land conservation and the detection of threatened and endangered species
Although the importance of conserving flora and fauna emerged early on in conservation history1,2, many of the first protected areas were preserved for their noted geological or aesthetic qualities. For example, Yosemite Valley was protected for both its forestry resources and geomorphological uniqueness (see photo above). However, biodiversity soon became an integral part of the establishment of protected spaces. Early land acquisition was inspired by the practice of forestry and aimed to protect forest lands2, and this goal was reinstated later in the century. Mid-century conservation goals shifted attention towards the preservation of species and biodiversity. Congress passed the Endangered Species Preservation Act in 1966, providing limited protection to federally listed endangered native species7. However, it was not until 1973 that the Act defined what endangered and threatened species were and expanded the definition to include plants and invertebrates.

The visualization History of Land Acquisition for Conservation also shows that the peaks of land acquisition in California did not match the peaks of threatened and endangered species detections and the spatial locations where these occurred. Several expeditions were conducted within the 20th century to survey the state’s biological diversity. Threatened and endangered mammal and bird species detections peaked from 1910 to 1940, corresponding to the surveys lead by Joseph Grinnell, director of the Museum of Vertebrate Zoology, University of California Berkeley, from 1907 to 1939. Threatened and Endangered Plant detections peaked in the 1930s and again in the 1980s. The 1930s peak corresponds to the survey lead by Albert Wieslander for the United States Forest Services. Many of these species were, in fact, listed as threatened and endangered as a result or after these surveys occurred. Only 3-8% of detections of threatened and endangered species occurred in the same spatial location and within the same decade as the land was acquired for conservation. This suggests that fauna and flora surveys in the state of California were temporally mismatched from conservation land acquisition, as they were driven by different missions, strategies, ideas, and funding. The first large extents of conservation lands in the state were acquired to protect forests and their aesthetic and recreational value. Subsequent land acquisitions were driven by other reasons such as water management, land availability, economics of the land market, and later for biodiversity. Additionally, there was a transition from the early 20th century top-down state level control of land use, to a more regional focus, and led to the creation of legal instruments and sources of funding for land acquisition (for example Special Districts), a funding source that was largely independent of the motivations and funding available for biodiversity assessments.
This photograph was taken in the summer of 1934 at Echo Lake in El Dorado County. It depicts a California ground squirrel, or Otospermophilus beecheyi. The photograph was part of the first fauna surveys conducted in the state. While not threatened in California (sensu IUCN categories), its range in California has significantly contracted over the last 80 years. Reproduced with the permission of The Museum of Vertebrate Zoology, University of California, Berkeley.
The fate of the redwoods: Early depletion shifts to concerted conservation
One of the species that captured the attention of logging interests and conservationists early on is the Coast Redwood (Sequoia sempervirens). Commercial logging operations commenced in the Santa Cruz Mountains in 1836 and the forest in this area was intensively logged for the next fifty years, although early technology prevented the removal of the most massive trees 8. Shown in the visualization Redwoods and sawmills are historical sawmill activities in operation from 1842 to 1950, historic and current redwood extents, and conservation land acquisition. In the 1880s the state finally began to impose controls on logging. In 1900, the first state park, Big Basin, was purchased by a group of wealthy conservationists who wanted to prevent the removal of the last remaining old-growth stand of redwoods in the Santa Cruz Mountains. Throughout the 20th century, other sections of the redwood forest in the region were purchased for state park lands, most of which were lands that had previously belonged to logging operations8. Contemporary studies have bolstered the perceived value of redwood forests, which have been recorded to have the highest biomass concentration levels on earth9. Their magnitude increases their utility in providing timber products, but the forests are also a source of fresh water, clean air, biodiversity and recreation10,11. The lifespan of redwoods can exceed 2,000 years12., which coupled with their record biomass concentration levels, have inspired recent research in their utility as a viable long-term carbon sink9,13,14,15. These findings point tentatively to augmented and strengthened conservation efforts in the future. The overall benefit of conserved lands to countering the effects of climate change in the Bay Area are discussed in a later section.
Redwoods and sawmills
The fate of the redwoods in the Santa Cruz Mountains. Open space acquisitions and sawmills through 1940 and areas logged after 1945.
Detail of historic topographic map with land cover types, as collected by the Wieslander surveys in 1930s.
Land by the Bay: Historic and Modern land cover
Redwood forests are not the only land cover type that were and are of interest for conservationists in the Bay Area, and most all land in the region has spawned contention over the last century. Today 30% of the area is urban, 30% is private, and the remainder is protected 16. Lands once covered with chaparral and oak woodlands were turned into agriculture land in the 20th century, which in turn was converted to today’s urban areas. The maps in visualization Land by the Bay show the land cover in the 1930s Bay Area and its counterpart today. Twelve of the seventeen land cover types present in 1930s were already incorporated in the conservation network by this decade. Exceptions occur for conifer and conifer-hardwood, which were only included to the conservation network in the 1960s. Grasslands have been the dominant land cover type within the conservation network since the beginning of the century, followed by oak woodlands and agriculture. Despite the volume of land that has been converted to agriculture and urban areas, all other land cover types have high representation (>20%) in today’s conservation network -- See the visualization conservation by the Bay. The only land cover types for which representation greatly deteriorated from historic to modern times are barren lands, hardwoods/oak, and wetland/riparian. Most of these changes occurred in the southern part of the study area, in Alameda, Santa Clara, and San Mateo counties. Small decreases in representation were found for agriculture, Douglas fir, and grasslands. 

The general pattern in land acquisition for conservation is a large acquisition of agricultural lands by all conservation agencies, while grasslands were the focus of acquisition for non-profits, special districts, cities, and counties. State agencies focused on agriculture and Federal agencies on coastal salt marsh. The portfolio of state and city parks includes a wider number of land cover types, with the least number of land cover types within Federal parks. Changes in land cover types inside and outside open space increased and decreased simultaneously for 15 land cover types, but the magnitude of change varied substantially. Area of agriculture, chaparral, coastal salt marsh, and hardwoods/oaks found both inside and outside open space decreased, while most other land cover types area increased. Three land cover types differed from this trend: barren lands and hardwoods/oak area found inside open spaces decreased, but increased in unprotected areas; and Blue Oak woodland area in open spaces increased while decreasing outside of them.
Land by the Bay
Historic and modern land cover in the San Francisco Bay Area
Conservation by the Bay
Open space acquisition by decade in the Bay Area
Strawberry Canyon in the Berkeley hills, and the urban East Bay beyond in 1935. Reproduced with the permission of The Museum of Vertebrate Zoology, University of California, Berkeley.
A house by the Bay: Urbanization and open space conservation
Land conservation has never been an easy process. From the onset, competition arose between developers and the conservationists who sought to maintain the aesthetic and biological properties of the Bay Area. San Francisco, once called an “instant city”17 due to its fast growth during the Gold Rush, continued to grow in the twentieth century. Increasingly this growth was not restricted to the relatively small land mass of the city, typified by earlier efforts to extend the land area near the city center by filling in the Bay. In contrast, growth in the twentieth century extended to the other counties around the Bay, facilitated by the implementation of major transportation routes—first railroads and then highways. The regional extent of this growth led to the creation of the Association of Bay Area Governments (ABAG). Today, ABAG sets guidelines for the proportion of lands developed and conserved, but relies on member city governments to voluntarily comply with those guidelines. On the other hand, the State of California and local municipalities collect fees from developers that are then earmarked for the purchase of open spaces. This creates an interesting feedback loop, as the availability of funds for open space acquisition depends on continued development. Bay Area inhabitants to this day seek to maintain current levels of aesthetics and quality of life while brisk population growth drives demand for increased development. The visualization a house by the Bay explores the dynamic relationship between the development of urban areas and transportation networks and the conservation of undeveloped land. Note the large swaths of land that become protected in the 1920s and 30s, and how the roads and urban extent boom in the 1960s. Compare the size of the open space parcels in non-urban areas to the tiny pieces of green within the dark grey urban layer. The peak of conservation is decidedly in the 1970s in terms of number of parcels conserved, but the average parcel size in this decade is much smaller than in previous decades. Parks and other open spaces were increasingly created in proximity to urban development, or in its midst, as a reaction to urban sprawl in the second half of the century.
A house by the Bay
Open space acquisition and land development in the San Francisco Bay Area
A view from Twin Peaks shows current-day San Francisco. Since early settlement this land has been desired for competing interests: its aesthetics, natural history, biodiversity, climate, but also as a place to live and farm. Photo by Maria J. Santos, 2012.
The rolling hills of the East Bay have been recognized for their quality of life, which has been associated with ranching, farming, and farm settlements. This photograph was taken at Mount Diablo State Park. Photo by Maria J. Santos, 2010.
Local repercussions of a global phenomenon: changes in temperature and precipitation in the Bay Area
While climate conservation has not been an explicit conservation goal during the 20th century, it is now, as anthropogenic climate changes have surpassed land cover change impacts, and climate changes have been observed in the Bay Area as elsewhere. Thus it is important to assess whether the evolution of the conservation network has had the added benefit of conserving climate variability, though this was not the explicit goal behind its establishment. One way to look at this question is to overlay the change in two climate parameters, precipitation and temperature, with the conservation network and analyze whether this network represents the climatic variation of the region. Across the entire Bay Area, the climate increased in minimum and maximum temperature and in precipitation. Minimum temperature changes ranged between [-0.5, 2.5]℃, maximum temperature changes ranged between [-0.7, 1.5]℃, and precipitation changes ranged between [3.6,156.1]mm. Open space climate changed in similar ranges for temperature (minimum temperature changing in between [-0.4,2.4]℃, maximum temperature in between [-0.7,1.4]℃), while areas with higher precipitation are not included in the Open space network (precipitation between [32.8,125.2]mm). Open spaces that changed the most in their climate characteristics (more or less than 2 standard deviations) have very different spatial locations, depending on the climate variable. For minimum temperature, Open spaces that changed the most are located in the southern Bay and East Bay Regional Park District. For maximum temperature, also the East Bay Regional Park District changed the most, as well as Lake Berryessa Recreational area. Open spaces that changed most in precipitation show a very scattered pattern mostly including small city parks around the Bay.
A view from Tilden Park, a property in the top of the Berkeley hills, acquired in the 1940s for $500,000. Today this land is valued two orders of magnitude higher. Photo by Maria J. Santos, 2010.
A view from the Castro and Market intersection in San Francisco, as typical late afternoon fog rolls into the city. The summer fog layer is very unique to the Bay Area’s Mediterranean climate, making it possible for species like the redwoods to persist despite the hot and dry climates found nearby. Photo by Maria J. Santos, 2012.
The future of California conservation history
Future threats to biodiversity and land conservation in California are predicted to be of greater magnitudes than those observed in the last 150 years. The era of major impacts from land cover change is transitioning to an era of major impacts from climate change. Admirably, a quarter of the state’s lands have been secured for conservation in some way. Will the current conservation network meet conservation goals in an uncertain future? For example, climate and vegetation communities in the San Francisco Bay Area are predicted to drastically change from what they are now. What we need is a richer record of conservation actions, an assessment of the performance of those actions, and dynamic improvements to the conservation network to meet current goals. History can teach us what has aided the environment and what has strained it; the future can allow us to improve upon and create innovative solutions for the challenges ahead. California has taken a leading role in the implementation of land conservation in the last 150 years, a legacy that holds promise for the future.
This project would have not been possible without the funding from the Spatial History Project (Wallenberg Foundation) and the Bill Lane Center for the American West, and the Vice-Provost Undergraduate Education program.

Several acknowledgements are also due to individuals and institutions for valuable contributions and data. 
  • Jon Christensen (formerly at the Bill Lane Center for the American West) at UCLA and Zephyr Frank at the Spatial History Project. Jon Christensen the Herbarium records.
  • James H. Thorne at the Information Center for the Environment at UC Davis for the Wieslander maps. 
  • Craig Moritz (formerly at the Museum of Vertebrate Zoology at UC Berkeley) at the Australian National University for supporting me when this project was a side project while working as his postdoc. 
  • Michelle Koo at the Museum of Vertebrate Zoology at UC Berkeley for access to mammal and bird museum data sets. 
  • Maggie Kelly and David Ackerly at UC Berkeley for the Wieslander data and collections, and conservation in the Bay Area.  
  • Open Space Council for bridging academia and managers. 
  • GreenInfo Network for creating and making available the invaluable California Protected Areas Database. 
  • Stanford Branner library, for the historical road maps for the San Francisco Bay Area and Los Angeles.
End Notes
1 Coates, P. “Emerging from the wilderness (or, from Redwoods to Bananas): Recent environmental history in the United States and the rest of the Americas.” Environment and History 10 (2004): 407-438.

2 Barton, G.A. “Empire forestry and American environmentalism.” Environment and History 6 (2000): 187-203.

3 Meir, E., S. Andelman, and H.P. Possingham. “Does conservation planning matter in a dynamic and uncertain world?” Ecology Letters 7 (2004): 615-622.

4 Olmsted, F.L. Report of the California State Park Commission. Sacramento: California State Park Commission, 1928.

5 Brooks, T.M, R.A. Mittermeier, C.G. Mittermeier, G.A.B. da Fonseca, A.B. Rylands, W.R. Konstant, P. Flick, J. Pilgrim, S. Odlfield, G. Magin, and C. Haig-Taylor. “Habitat loss and extinction in the hotspots of biodiversity.” Conservation Biology 16 (2002): 909-923.

6 Calsbeek, R., J.N. Thompson, and J.E. Richardson. “Patterns of molecular evolution and diversification in a biodiversity hotspot: the California Floristic Province.” Molecular Ecology 12 (2003): 1021–1029.

7 U.S. Fish & Wildlife Service. “A History of the Endangered Species Act of 1973.” 2011. Retrieved from

8 Payne, S. A Howling Wilderness: A History of the Summit Road Area of the Santa Cruz Mountains 1850-1906. Santa Cruz: Loma Prieta Publishing Company, 1978. Retrieved May 20, 2012 from:

9 Fujimori, T. “Stem biomass and structure of a mature Sequoia sempervirens stand on the Pacific Coast of Northern California.” Journal of the Japanese Forestry Society 59 (1977): 435-441.

10 Poli, A. “Ownership and use of forest land in Northwestern California.” Land Economics 32 (1956): 144-151.

11 Fritz, E. “The redwoods of California—largest of economic plants.” Economic Botany (1966): 51-56.

12 Olson, D.F., D.F. Roy, and G.A. Walters Sequoia sempervirens (D. Don): Redwood. United States Department of Agriculture, Forest Service, 1965. Agriculture Handbook 654.

13 Mader, S. Climate Project: Carbon Sequestration and Storage by California Forest and Forest Products. CH2M HILL, 2007. Forests for the Next Century, Technical Memorandum 2-30.

14 Hudiberg, T., B. Law, D.P. Turner, J. Campbell, D. Donato, and M. Duane. “Carbon dynamics of Oregon and Northern California forests and potential land-based carbon storage.” Ecological Applications 19 (2009): 163-180.

15 Jones, D.A. and K.L. O’Hara. “Carbon density in managed coast redwood stands: implications for forest carbon estimation.” Forestry (2011): 1-11.

16 Santos, M. J., J. H. Thorne, J. Christensen, and Z. Frank. "An historical land conservation analysis in the San Francisco Bay Area, USA: 1850 to 2010.” Landscape and Urban Planning 127 (2014):114-123.

17 Barth, G.P. Instant Cities: Urbanization and the Rise of San Francisco and Denver. New York: Oxford University Press, 1975.