Botany in San Diego County before European Contact

By Tom Oberbauer, President CNPS-San Diego

It is fascinating to contemplate the appearance and distribution of biological natural resources in San Diego County at the time of the first European contact. Because San Diego County is now one of the more populous counties in the U.S., it is sometimes difficult to imagine what it looked like a mere 500 years ago. All the land that is now covered by urbanization and agriculture was originally natural and inhabited by a wide array of plants and animals and what is more interesting is that our ever present Mediterranean weeds were not here. Just imagine land without Avena fatua (wild oats) and brome grasses (Bromus madritensis, B. hordeadeus and B. diandrus) and the ever present Red-stem filaree (Erodium cicutarium). Their absence means that other species already existed in the areas that they now inhabit. When considering the combination of land that is converted to urban and agricultural lands and the land that is inhabited by non-native weeds, a very large area of San Diego has very different land cover than what originally occurred here.

A number of sources exist that will provide a glimpse into the past at the time of the first exploration of San Diego County by Europeans. The first documents were reports of the findings of Juan Rodriguez Cabrillo in 1542 and Sebastián Vizcaíno in 1602. However, one of the primary sources of information is from the writings and journals of Padre Juan Crespi, who passed through San Diego on foot in 1769. This was already 200 years after the first European visitors.

In addition, a moderately large and stable population of native people lived here, harvesting wildlife, managing the landscape through occasionally burning and using plant resources for survival. Based on recent findings of the San Diego Natural History Museum, people have been here for at least 120,000 years. Their presence already had an influence on the natural history landscape in this region, but they existed in a time of natural balance. There are estimates that there were tens of thousands of people in the area at the time of contact (Indian Country Diaries 2006, Killea 1975). The landscape reflected the activity of the local people.

This discussion will be in four parts, beginning at the coast, foothills and valleys, mountains, and, lastly, the deserts. The coastal area has probably undergone the greatest change of any of the region since contact. However, at the time of contact, the coast, as well as the rest of the County, would have been a naturalist’s and wildlife lover’s paradise. Along the coast are remnants of native vegetation located on Point Loma, parts of Mount Soledad, and of course, Torrey Pines State Reserve.

The coast

Layia platyglossa

Camissoniopis bistorta

It is well known that even in the first generation of the 20th century, wildflowers were prevalent along coastal areas. Carroll DeWilton Scott (1955) had black and white photos of fields of Layia platyglossa (Tidy tips) in the coastal areas near what is now Mission Bay as late as the 1920s. The shrubby vegetation would have been present, including the existing coastal sage scrub and chaparral on the upper slopes, but instead of grasses between the shrubs, the openings would have been covered with wildflowers. There are also a few photos around of the Ocean Beach area covered with Tidy tips. The Tidy tips would have been augmented by a smaller- flowered coastal form of Eschscholzia california (California poppy), and extensive patches of Camissoniopsis spp. (Sun cups) of more than one species; probably at least on the coastal sandy areas Beach evening primrose (Camissoniopsis cheiranthfolia), California sun cup (Camissoniopsis bistorta) and small-flowered evening primrose (Camissoniopsis micrantha).

San Diego Bay was a breeding area for California gray whales, so their spouts, breaches, and spy hops would have been visible throughout the deeper parts of the bay during the winter months. San Diego County was well known for the presence of Grizzly bears late in the time of final occupation. Cave Johnson Coutes (1849) remarked about the numbers of Grizzly bears encountered on a trip he took through the mountains near Julian down to Fort Yuma. The Grizzlies here were also larger with massive bears being killed near Valley Center and on what is now Camp Pendleton (Valley Center Historical Society, Tremor et al. 2017). Grizzlies would have been found in the major river valleys, the San Diego, San Luis Rey, Sweetwater, and Otay, which would have been feast areas with access to a variety of plants and animals. It is not just that there were a few Grizzlies around, but based on historic accounts and references, they were numerous.

Elephant Seals

The coastal beaches and coves such as La Jolla Cove would have supported numbers of Harbor seals, Elephant seals, California sea lions, Sea otters and potentially Guadalupe fur seals. As mentioned, Gray whales collected and bred in San Diego Bay at the time. All these groupings of wildlife suffered occasional mortality that would have drawn numbers of Grizzly bears. California condors would have also been numerous in the County, feasting along with the Grizzly bears on the mortality of the pinnepeds and whales. The pinnepeds also drew native people who occasionally harvested them (Antonelis and Fiscus 1980). Imagine the La Playa area of Point Loma covered with wildflowers down near the shore, Tidy tips and California poppies, while Grizzlies and packs of Coyotes feasted on some dead Elephant seals and a Gray whale that washed up on shore as a number of Condors swoop down on the remnants.

Dichelostemma capitatum Photo by Michael Evans

Bloomeria crocea


Another plant that would have been very widespread and that even seems to thrive with disturbance was Dichelostemma capitatum (Wild hyacinth) that has blue flowers on the end of tall stalks. Dichelostemma is a geophyte that supports a corm (a bulb-like structure) that doesn’t have layers like onions but does have a central starchy center. These were harvested by the local people for a meager food source and they could have been also important food for Grizzly bears, which were known for eating anything that is edible, even grass. The landscape effect of Grizzly bears on the vegetation overall may have been subtle, but they, like coyotes, may have also eaten berries from shrubs including Arctostaphlos spp. (Manzanita) in addition to other bulbous geophytes likecAllium haematochiton (Red-skinned onion), Muilla maritima (Sea muilla) and Bloomeria crocea (Golden stars) and maybe even Bloomeria clevelandii (Cleveland golden stars), which is found only in San Diego County and part way down the Baja California peninsula. In some cases, digging up bulbs of geophytes has a result of stimulating their growth.



Salvia columbariae

The native people were known to use fire to enhance different food plants like the geophytes as well as some seed- bearing plants like Salvia columbariae (Chia). Early explorers mentioned smoke in the fall in Southern California from the intentional burning that occurred. This would have also opened up the vegetation in the burned areas with a mosaic of lands that had not burned for a while and those that had, creating an equilibrium consisting of a mix of young and old vegetation in a changing surface pattern. Some areas, due to their geographic terrain and moisture regime, would have not burned as frequently; the Torrey Pines area for example, and probably Point Loma.

Arctostaphylos glandulosa ssp. crassifolia

The original vegetation of Point Loma is an interesting subject of its own. The tryworks (furnaces), where killed whales from San Diego Bay were cut up and cooked to obtain oil from the blubber, were located at Fort Guijarros on the Bay side of Point Loma. Wood for fuel would have likely been harvested from the nearby locations to avoid having to transport it, which would mean that any trees or large shrubs that were within reach would have been utilized for fuel and maybe along with the use of some of the blubber itself for fuel. One can imagine the canyons of Point Loma with dense thickets of Quercus berberidifolia (Inland scrub oak) and Quercus dumosa (Nuttall’s scrub oak) around the point and there is a potential that Torrey pine (Pinus torreyana) may have grown there as well. Torrey pines that were planted some time ago are now present without irrigation and doing well, indicating that the conditions that could support them exist on Point Loma. However, it is not as probable that Quercus agrifolia (Coast live oak) was growing there at that time because of soil and climate conditions that are not as favorable for it. The chaparral that still exists in parts of coastal San Diego County, dominated by Adenostoma fasciculata (Chamise), Ceanothus verrucosus (Wart-stemmed ceanothus), Arctostaphylos glandulosa ssp. crassifiolia (Del Mar manzanita), would have occurred in the areas of Maritime Chaparral that grew on sandstones on Point Loma and other coastal areas. Large Rhus integrifolia (Lemonadeberry) was probably also harvested for wood on Point Loma. So, on the coastal ridges, chaparral would have been present as it is today.

Adolphia californica

The vegetation of downtown San Diego and the lower slopes around San Diego Bay, the mouth of the San Diego River, and the south-facing slopes, which include the canyons, and river valleys, would have all been covered with Coastal sage scrub. South of Chollas Creek and east of what is now Balboa Park and down across the mesas southward, Coastal sage scrub was most of the vegetation. However, north and west of these locations, including the upper mesas and what is now San Diego State University and Linda Vista on the northern mesas, the vegetation was chaparral on the upper parts, mostly Chamise-dominated but with mixed species on the north slopes. In the northern part of the County, Coastal sage scrub would have covered the south-facing slopes and the major drainages, San Diego Bay to the slopes around the lagoons and the slopes on the coastal mesas of modern Camp Pendleton with the exception of areas with fine soils. The fine soils, clays and fine silts, would have supported natural grasslands of Nassela species, probably Nassella pulchella (Purple needlegrass), Nessella lepida (Foothill needlegrass) and a large number of wildflowers, such as Sidalcea malvaeflora (Checker mallow), Dichelostemma, Viola pedunculata (Johnny jump-up), Amsinkia intermedia (fiddlenecks), Sisyrinchium bellum (blue-eyed grass) and swaths of Layia platyglossa and mixings of Eschscholzia californica. A clay soil inhabiting shrub, the Adolphia california (California adolphia), would have been scattered around the fringes of the grasslands on the coastal terraces north of the San Luis Rey River and San Mateo Creek to San Onofre Creek, and patches in a variety of locations.


Another large mammal with a strong presence in coastal San Diego County was the Pronghorn. The early explorers observed numerous bands of them across the mesas and terraces. They are known browsers and while in modern times they are found in parts of the west where Artemisia tridentata (Great basin sagebrush) grows, in coastal San Diego County, they fed on Coastal sage scrub, probably including Artemisia californica (California sage brush), which is a relative of the Artemisia tridentata. Their presence in good numbers would have also enhanced the openness of the vegetation in some places. The mix of browsers and periodic fires in a vegetative mosaic would have helped maintain a variety of levels of shrub density. Where the shrubs were older and more dense, they would have supported the now endangered California gnatcatchers. Where shrubs were less dense, they would have supported Rufous-crowned sparrows. Again, the lack of weedy grasses at that time means that their place in the ecosystem was represented by other species that would have included some native grasses but also areas composed mostly of native wildflowers.

Pogogyne nudiuscula photo by Tom Oberbauer

A large part of the flat mesas was covered with depressions and mounds. The mounds were covered with shrubs but, just as today, not the depressions. This is because standing water drowned the roots of the shrubs in the deeper basins that fill with winter rainfall. Vernal pools with their array of flowers and reproducing toad and frog larvae may have been food for Grizzly bears who could have harvested the larvae and adult animals and extracted the Brodiaea orcuttia (Orcutt’s brodiaea) that grows in profusion in pool bottoms. Eryngium aristulatum var. parishii (San Diego button celery) could have also been a food sources and the geophytic root bases would have been prolific in the pool bottoms along with Pogogyne abramsii (San Diego Mesa mint) and P. nudiuscula (Otay Mesa mint). While conditions right along the coast would have supported Eschscholzia californica mixed with other species, such as Linanthus dianthiflorus (Fringed ground pink), which I have seen covering whole hillsides, one cannot overstate the importance of Eschscholzia. Explorers moving northward in ships along the California coast are reported to have thought that the hills were on fire because they were covered with orange California poppies. Other important species include Leptosyne maritima (Sea dahlia), which itself forms dense patches of bright yellow, but would have had a greater opportunity in canyons and Encelia californica (California encelia) and Bahiopsis lacinitata (San Diego sunflower) would have painted south-facing slopes yellow, particularly immediately along the coast and inland to the foothills following good rainfall seasons.

Riparian river valleys were undoubtedly wetter than they are now because wells did not draw down the water tables at that time and dams did not collect rainfall runoff. On the other hand, there are now locations near the coast where the water table may be slightly higher than the pre-contact levels due to the collective levels of runoff from urban irrigated landscaping. Dense forests of riparian vegetation would have existed in the major stream and river courses extending to the coast. They would have also had some variation in age and density of vegetation due to the periodic flooding that would have occurred, scouring out trees and shrubs that would then establish anew. We still have many of the major riparian areas but with reduced area, particularly in the valleys and interior regions.

Coastal San Diego County was a wildlife wonderland with Grizzly bears, Jaguars, and Pronghorns along with Southern mule deer, Coyotes, Bobcats, California condors, Swainson hawks, Golden eagles, Bald eagles, Peregrine Falcons and other wildlife species we still have. The views across the landscape following a good rainfall season must have been spectacular with multi-hued patches of orange, yellow and blue in the foreground over the terraces and valleys mixed with shrubs and hillsides of dark chaparral covered blue and white in the spring due to Ceanothus tomentosus (woolly-leaf ceanothus) and Ceanothus verrucosus (Wart-stemmed ceanothus), with Black Mountain, San Miguel Mountain and Mount Soledad as the backdrop.

Foothills and valleys

East of the coastal zone, the modern impact on vegetation may not have been quite as extreme as that along the coast, but Escondido, Ramona, El Cajon and Alpine have replaced large areas of native vegetation with urbanization and rural development and, in some areas such as around Fallbrook and southward, agriculture has replaced vast areas of natural habitats.

Proceeding east from the coast, competing forces of greater seasonal precipitation and higher seasonal temperatures take place. Overall, rainfall increases on average due to rising elevation but some pockets in the valleys suffer from the rain shadow effect that combined with the higher temperatures creates more xeric conditions. The pattern of vegetation may be quite complex with chaparral on north-facing slopes and coastal sage scrub on south-facing slopes. Where erosion and rock features create topographic variation, the pattern of vegetation will have been and still are in locations where the distinction between vegetation patches is very abrupt.

The adverse effect of weeds is overall present in the foothills and valleys. Again, the effect of fire, both occurring as the result of natural weather phenomenon and the effect of the manipulation of the land by the native people, will have been the generation of much more diverse age classes of vegetation. 

Linanthus dianthiflorus photo by Tom Oberbauer

In the absence of weeds and the presence of more open vegetation before contact, there is no reason that wildflowers would not be prevalent almost every spring season. There has been documentation about the flowers of the Los Angeles Basin (Minnich 2008). Even when rainfall is well below seasonal averages, after fires, wildflowers can exhibit nice displays due to the initial lack of weed growth. Prior to weed invasions, flowers like Eschscholzia californica and Linanthus dianthiflorus, as well as Dichelostemma capitatum, would have been the ground cover. It is notable that even though the Eschscholzia californica along the coast is more of a pale yellow, the flowers on interior plants are larger and a more richly colored orange. In the Del Dios area and east of Poway in the spring of 2008, a slightly below normal rainfall season following the massive fires of October 2007, created spectacular color where the deep orange poppies covered the hillsides. Imagine nearly every spring large patches of orange on hillsides where it existed in open areas and mixed among openings between the shrubs.

Hesperocyparis forbesii photo by Tom Oberbauer

The chaparral vegetation would have grown with a mixed pattern. Some areas would have been younger patches with strong, succulent new growth while others would have been older growth vegetation. It is likely that due to topography, slope and wind conditions, some areas would have burned less frequently because of wind pattern idiosyncrasies due to the slope of the terrain and direction of air flow. Otay Mountain and Tecate Peak would have supported healthy, robust Hesperocyparis forbesii (Tecate Cypress) forest, that grew to large sizes before being consumed by fire with a frequency of roughly once every one-half to a full century. Large trees existed as recently as the mid-1970’s but multiple fires recently have left only younger, smaller trees. Major fires would have likely been more associated with summer rather than fall since there would have been fewer ignition sources. The native people who lived in the environment would have understood the effects of wind and low humidity during the Santa Ana conditions, which are the most common fire periods of modern times. Mistakes with fire during these periods could have been catastrophic for local inhabitants. The fact that the Tecate cypress on Otay Mountain and Tecate Peak was so robust in the last 50 to 75 years is an indication of conditions in which they were somewhat protected by wind patterns and air flow from too frequent fire that would have eliminated them.

Acanthomintha ilicifolia photo by David Varner.

The valleys like El Cajon, Escondido, Poway and even Ramona would have had Coastal sage scrub habitat on the floor. It was probably dominated by Eriogonum fasciculatum (California buckwheat) since it seems to grow best in these sorts of conditions. However, parts of Ramona could have supported natural grasslands of Nassella species as well as clay soil inhabitants including Acanthomintha ilicifolia (San Diego thornmint) and Convolvulus simulans (Small-flower bindweed). Vernal pools were also widespread in the valley bottom with Downingia cuspidata (Toothed downingia) patches and Calandrinia menziesii (Red maids) flowers nearby. Pronghorn would have been part of the fauna in these areas as well, with bands of them roaming about on the open valley landscape, pruning down the shrubs. One can visualize them across the northern portion of Ramona with the northern hills in the background.

Quercus engelmanii

In the foothills and interior valleys, riparian woodland would be growing well since no groundwater extraction resulting from deeply drilled water wells would have affected the water table. Even during dry years, the underground reservoir formed from the rocky crevices and sandy valley sediments would have held water for far longer into the dry season than they do now. Oak woodlands which now grow on the some north facing slopes and hillsides such as at Singing Hills and Alpine would have been even more prevalent in the valleys such as Viejas Valley. Quercus engelmannii (Engelmann oak) would have been even more common than it is now. The foothills and valleys would also have been one of the favored homes of the Grizzly bear, especially in the riparian areas. Chamise chaparral and chaparral mixed with a variety of species including Xylococcus bicolor (Mission manzanita), several species of Ceanothus including C. tomentosus, C. leucodermis (Chaparral whitethorn) and C. crassifilolia (Thick- leaf lilac), as well as Arctostaphylos glauca (Big-berry manzanita) and A. glandulosa (Eastwood Manzanita) in some areas, would have been the dominants as they are today and more resistant from fires. If for some reason a fire occurred in an area in close succession so that the shrubs were displaced, wildflowers would have filled in the void left by the shrubs.

Chamaebatia australis

Nolina cismontana

The foothills are where the effects of gabbro and metavolcanic soils are most prevalent. McGinty Mountain, Viejas, Poser, Barber, San Marcos Mountains, and mountains near Rainbow are composed of gabbro. San Miguel Mountain and the Jamul Mountains in addition to Otay Mountain are composed of metamorphic volcanic rock. Iron Mountain is composed of metamorphosed sedimentary rock. Each of these rock types produce soil that is somewhat limiting for plants due to low nutrients or high concentrations of magnesium and iron. The plants that grow on these soils are able to overcome the apparent limitations of the soil mineral composition so a number of them are rare and different or at least interesting. These mountains composed of gabbro and metavolcanic rock have some similar components of vegetation associates. These may include the fern-like leaved Chamaebatia australis (Mountain misery), Tetracoccus dioicus (Parry’s tetracoccus), Packera ganderi (Gander’s butterweed) and Nolina interata (Dehesa nolina) and N. cismontana (Chaparral nolina) on some of the gabbro soils and Lepechinia ganderi (Gander’s pitcher sage) and Clinopodium chandleri (San Miguel Savory) in addition to Chamaebatia australis on the metavolcanic and metasedimentary mountains. Tecate cypress also occurred and still occurs on both sets of gabbro and metavolcanic rock types. As mentioned earlier the cypress was probably a bit larger in area than it is now, especially near Tecate Peak. The other species would have ebbed and flowed depending on the cycle of burning.

There is a question regarding whether or not Bighorn sheep occurred on the west side of the mountains in the past. There were unsubstantiated rumors in the 1970’s that Bighorn sheep occurred on Otay Mountain. They could have occurred on the west side of the mountains outside of the desert and mountain realm.

It is difficult to tell if there have been changes in coverage between Coastal sage scrub and Chaparral other than the areas where they have been removed by urban and agricultural development. Before Europeans arrived, animal browsing and fires may have kept the vegetation open. However, during the late 1800’s and early 1900’s cattle grazing was heavy. A set of 1927 aerial photographs provide an indication of just how affected the vegetation was with slopes and large areas with little shrub vegetation of any kind tha later recovered with Coastal sage scrub in some places and forms of Chaparral in a few locations. Therefore, in addition to the major losses of vegetation by modern development, the boundary between Chaparral and Coastal sage scrub vegetation may have been affected, but how much is hard to say. Since the distribution of Coastal sage scrub and Chaparral seems ultimately to be driven by precipitation and whether a slope is north or south facing, it may be that the boundaries between Chaparral and Coastal sage scrub have not changed significantly. However, repeated fires of the past quarter to half century have in some locations provided an avenue for non-native weedy species to take over the Coastal sage scrub locations. In other locations, such as the area below the Alpine View Point on I-8, repeated fires in Chaparral, even when burned several times in a dozen years, have not changed the chaparral and it has recovered. It may be that Chaparral has recovered more readily than Coastal sage scrub due to Chaparral species being able to resprout, which may provide an advantage over the now prevalent invasive non-native annual plants that grow in this region.

At the time of European contact, Rancho Jamul, Viejas Valley, the valleys formed by the middle and upper San Luis Rey and the valleys filled by El Capitan, San Vicente, Otay, and Barrett reservoirs were also full of Coastal sage scrub habitat except the valley bottom where the stream courses passed through which would have supported Riparian woodland. So, overall, in the foothills and valleys, the patterns may not have been that much different than there in modern times except for the displacement of vegetation by the foothill towns and agricultural development. The situation has been mainly a displacement rather than a conversion of the type of vegetation growing in an area with the exception that the non-native weeds have impacted some areas of Coastal sage scrub, especially in the past two decades.

One sad state of affairs is the human caused invasion of gold spotted oak borer and shot hole borer beetles. They are impacting more forest, both oak in the case of the oak borer, and riparian in the case of the shot hole borer, than any other activities of the past half century and maybe longer. Their lasting effects will be fewer trees naturally growing in San Diego County.


For the mountains, the effect of European settlement on vegetation is a mix of some areas that are very similar to pre- contact coverage but other areas that are different. The wildlife species have changed as well.

First, the Coniferous forest areas were larger than they are now, particularly since the fires of 2002, 2003, and 2007 which have killed off coniferous forest lands. Under natural conditions, periodic fires more frequent than in the lowlands would have burned off the understory and kept the forest more open (Van der Water and Safford 2011; Sugihara, Wagtendonk and Shaffer 2006). When a fire burned through the coniferous forests of Laguna, Cuyamaca, Palomar, Volcan and Hot Springs Mountains, very little mortality of the adult trees occurred because the trees were spread far enough apart that crown fires would not have commonly occurred. Huge old trees were relatively common, trees that survived many fires over the centuries. A few of these same trees are still alive though there were more prior to 2003. Trees 180 feet tall and five feet plus in trunk diameter grew on the upper parts of the Cuyamaca Peak prior to some of the older fires in the early 1950s (Cuyamaca Rancho State Park information) and at least 166 feet and one 9-foot diameter tree on Middle Peak prior to the 2003 fire. This enormous tree may have already been several hundred years old at the time of European contact (Oberbauer 1975; personal observation).


Grizzly bears were relatively common as were deer. There are records about the high number and, as mentioned, the size of the bears that occurred in this region. There were so many that they were market hunted for their meat and it was shipped to the San Francisco Bay area. However, one other animal that is not mentioned much and which would also have occurred here was the Jaguar (Felis onca). Jaguars are thought to have occurred as far north as Monterey, with the last one in Southern California in 1860 in Palm Springs where it was shot while apparently stalking someone dressed in a deerskin camouflage outfit. They didn’t just occur in the mountains and forest but also down into the desert. One was killed in Baja California in the southern tip of the Sierra de San Pedro Mártir in 1955 (Sundquist and Sundquist 2017). Their predominant food was likely Mule deer or Bighorn sheep. Bighorn sheep were also numerous, probably occurring in the mountains as well as in the desert as they do in the San Gabriel Mountains. With this somewhat different mix of large animals present, there were likely subtle differences in the vegetation caused by different browsers and grazers and potentially the digging capabilities of the bears.

Castilleja densiflora

Lupinus bicolor

Mention of valleys in the mountains suggests meadows with extensive wildlflowers nearly every spring. Layia platyglossa formed expanses around the boggy area that is now Cuyamaca Lake. Castilleja densiflora (Dense owl’s clover) mixed with Lasthenia gracilis (Goldfields) and Platystemon californica (Cream cups) and Sidalcea malvaeflora (Checker mallow) grew in profusion in main part of the meadows and valley areas such as Laguna meadow, the very wet area that is now Cuyamaca Lake, and Doane, Will and Dyche valleys on Palomar Mountain. The vast Valle de San Jose and its associated tributary valleys near Morrettis Junction and near Mataguay Boy Scout Camp contained yet another type of Eschscholzia californica. These poppies generate flowers that may be nearly 3 inches across and of deep orange color. In some places, they may be mixed with Malacothrix glabrata (Desert dandelion) and Linanthus dianthiflorus, Lasthenia gracilis and Lupinus bicolor (Miniature annual lupine) flowering in a vast cover of orange and blue. Occasionally small remnants of this are found today following good rainfall seasons. Roving bands of Pronghorn occurred in these areas as well, trampling the flowers in some locations as they moved across the vast landscape with a backdrop of the San Ysidro Mountains, including Hot Springs Mountain and Palomar Mountain. 

After contact, logging did occur in the mountains. Logging of local forests would have generated timber for the construction of the Stonewall Jackson gold mine that generated many millions of dollars in gold. Forest areas around Cuyamaca Lake and Julian were cut and sawed or burned. In the 100 years that have passed since logging, forest grew again in some of the areas as illustrated by the trees in the area where the Stonewall Jackson mine once occurred south of Cuyamaca Lake. There may have been permanent changes in the overall extent of the forest compared to what was present before the development of Julian and before the mines were constructed.

Palomar Mountain was important in a similar way where some forest was cut, but the extent is not known. Only two Pinus lambertiana (Sugar Pine) trees have been found on Palomar Mountain and one wonders why more don’t occur there. Sugar pine wood is highly prized and could have been cut selectively, but a question would be if people would have gone to so much trouble to concentrate on them rather than the abundant Pinus jeffreyi (Jeffrey pine), Abies concolor (White fir) and Calocedrus decurrans (Incense cedar).

Hesperocyparis stephensonii (Cuyamaca cypress) grew in a limited area on the west slopes of Cuyamaca Peak. Cuyamaca Peak is composed of gabbro, which as mentioned earlier, supports unique vegetation due to the presence of high concentrations of magnesium and iron. Was Hesperocyparis stephensonii more widespread before repeated fires beginning in the 1950s?

A massive fire in the Cuyamaca Mountains during the early 1950’s was one of the initial forces for destroying old growth forest, killing off Pinus lambertiana on Cuyamaca Peak that were reported to be 180 feet tall. Five-foot diameter stumps existed on Middle Peak in the 1970’s.

While still part of the mountain area but in a more desert trending zone, the area around Jacumba was reported to have suffered a large fire in the early part of the 20th century. Pinon pine forest that was widespread in that region was reported to have been burned and did not regrow. Pinyon pines (Pinus monophylla) are currently absent in most of the Jacumba area though there are a few in the vicinity of In-Ko- Pah County Park, not far away, and significant groves occur among granitic rock formations in the Jacumba Mountains to the east.

Some of the greatest impacts in the mountain areas since European people arrived occurred in the past few decades. Prolonged drought in the late 1980’s and early 2000’s killed off large areas of Pinus coulteri (Coulter pine) in the southern part of Palomar Mountain and Pinus jeffreyi in the hills around Julian, in addition to forests in the Cuyamaca and Laguna Mountains.

When these areas burned in the Palomar Mountain fire of 1999, the Pines Fire, Cedar Fire, Poomacha Fire, Volcan Mountain fire and Hot Springs Mountain fire over the last 20 years, huge losses in forest vegetation occurred. The Cedar Fire alone destroyed at least 20,000 acres of Coniferous forest. In the absence of any adult trees, since all conifers were killed in massive crown fires in much of these areas, reproduction or natural regeneration of these forests is not occurring without assistance. A more natural stand density may have allowed fewer standing dead trees since fewer trees competed for the lower rainfall, and with a more open forest of lower density, more trees might have been spared by the fires. Chaparral has been the winner in these burn areas since 2003. Ten-foot tall pure stands of Ceanothus palmeri (Palmer ceanothus) replaced the trees in much of the 20,000 acres mentioned earlier. Except for the spread of chaparral into what was formerly forest lands, the major change in the forest areas since European settlement in San Diego County is one of loss.

Pinus coulteri

Pine Mountain on top of Rancho Guejito is a case in point. Prior to 2003, it supported a significant stand of Pinus coulteri on the highest locations. The fire killed large areas of trees and their trunks appear like bleached match sticks on Google Earth aerial photos. Few of the pines are growing back now as is also evidenced on Google Earth.

Populus fremontii

However, the effect of centuries of cattle grazing should not be understated. Oak woodland reproduction has halted in areas where cattle graze heavily and old trees eventually die without reproducing. This has happened in the Valle de San Jose east of Lake Henshaw. Riparian forests of Populus fremontii (Fremont Cottonwood) and Salix species (willows) with Quercus agrifolia (coast live oak) would have been extensive in these areas. They have been gradually eliminated by heavy grazing with remnants near Morretis Junction and east along the Highway S-2.


Abronia villosa, Oenothera detoides & Gerea canescens photo by Tom Oberbauer

One might think that the desert portion of San Diego County may not have had many changes since the area was occupied by Europeans. However, again, the absence of weeds provided for enhanced wildflower growth. The predominant weeds Brassica tornifortii (Sahara mustard) and Bromus tectorum (Cheatgrass) at the higher elevations, and Schismus barbatas (Common Mediterranean grass) along with Erodium cicutarium have become a major complication of the vegetation growth especially the Brassica, which seems to have had its greatest effect in the past couple of dozen years. In some parts of Borrego Valley, displays that are reminiscent of what would have been more common occasionally occur following good rainfall seasons. With the absence of weeds, Abronia villosa (Sand verbena), Oenothera deltoides (Birdcage evening primrose), Geraea canescens (Desert sunflower) and Malacothrix glabrata (Desert dandelion) would have filled every void between the Larrea tridentata (Creosote bush) and the Fouquieria splendens (Ocotillo) more frequently than they do now.

Prosopis velutina

Another area where the deserts have suffered is in groundwater draw down. The groundwater table of Borrego Springs has been gradually lowering for decades as water is pumped out. Even Prosopis glandulosa (Honey mesquite) and the non-native Prosopis velutina (Velvet mesquite), which is notorious for being deep rooted, are eventually adversely affected. The Mesquite Bosque in Borrego has been declining as water that fell as rain hundreds and thousands of years ago is drawn out for irrigation of land around Borrego Springs.


Lucy’s Warbler

An interesting set of birds that inhabit the bosque include Lucy’s warbler, Crissal thrasher, and Gambel quail. Mesquite Bosque has covered a combined area of approximately 3,868 acres in the desert but continues to shrink. Fewer than 2,500 acres exist in the main area near the Borrego Sink, but with many dead trees. While the Lucy’s warbler has only been detected there since 1990, their history indicates ebb and flow so that they could have moved around and could have been in this area before detected in the 1990s. With more groundwater, the bosque was probably larger and it is also likely that mesquite was more widespread elsewhere in the Borrego desert.

It is hard to say if the palms would have been growing in additional or different locations than where they do today. The ones that grow are occasionally affected by human caused fires but the native people would have burned as well. They are also periodically subjected to massive flash floods that topple large trees and carry them downstream. Along the edge of Borrego Valley, they could have been more prominent prior to the drawdown of the water table.

Pinyon pine forests on Whale Peak and elsewhere seem to have been little affected by the presence of European inhabitants. These forests have never been commercially exploited and they grow in remote enough areas that they don’t appear to have been cut to any significant level and mining operations did not appear to have had major land clearing efforts there either.

Furthermore, they seem to be more resilient to drought because during drier winters resulting from lack of Pacific storms, the summer monsoon in the desert has often made up for the lower precipitation. While the Cuyamaca and Julian trees were dying from drought and bark beetles, these trees seemed to be little affected.

Bighorn Sheep

At the time of European encounters, the desert wildlife would have also been somewhat different than modern times. Pronghorns were also present down in the desert where bands of pronghorn moved across the lowlands such as Borrego Valley. On the rocky hillsides and canyons, Bighorn sheep were also much more common than they are now, coming down out of the mountains and hills to drink in the canyon bottoms. In the absence of well draw down, the Borrego Sink may have held water more consistently than it does now.

The major change in vegetation in the desert has been the invasion of weed species. In place of the weeds the native wildflowers would likely have not only been more prevalent but more widespread as well. San Diego County still supports more species of most plants and animal groups than any other County in the United States, even though it has been affected by 500 years of impact. While the Grizzly bears and Jaguars may have created danger, they along with the Pronghorns and large populations of deer from the coast to the desert and marine mammals in San Diego Bay and along the coastline California condors and numerous bird and mammal species and the continuous cover of wildflowers in openings in the vegetation, would have made an area that is still a truly spectacular place biologically.


Indian country diaries 2006 Assimilation, relocation, genocide

Antonelis, G. A. Jr. and C. H. Fiscus. The pinnipeds of the California current. CalCOFI Rep. Vol. XXI:68-78.

Killea, Lucy Lytle. “Colonial Foundations of Land Use and Society in San Diego, 1769-1846.” Ph.D., History, 1975. University of California, san diego

Scott, C. D. 1955. Story of Southern California Wildflowers (1955) Valley Center History Museum. 2015. Grizzly Bear

Tremor, Scott. 2017. Mammal Atlas San Diego County.

Minnich, R. A. 208. California’s fading wildflowers, lost legacy and biological invasions. Berkeley: University of California Press, 2008. Project MUSE,

Van de Water K. M. and H. D. Safford, 2011: A Summary of Fire Frequency Estimates for California Vegetation before Euro-American Settlement. Fire Ecology Volume 7, Issue 3: 26-58

Sugihara, N., J.W. van Wagtendonk, K. Shaffer, J. Fites-Kaufman, and A.E. Thode. 2006. Fire in California’s ecosystems. University of California Press, Berkeley, USA.

Sundquist, M. and F. Sundquist. 2017. Wild Cats of the World. University of Chicago Press.

Oberbauer, T. 1975. Pinus Lambertiana. Forest Ecology, San Diego State University.