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Introducing Orange County

From the look-alike cities in the north to the newer, planned communities of the south, Orange County seems little distinguished from its colossal neighbor and economic parent, Los Angeles. But a deeper identity, rooted in geography, transcends the urban sprawl. Orange Countians are reminded of their uniqueness not so much by the human architecture of city and suburb, but rather by the blue Pacific, the green and tawny coastal hills, and the purple wall of the Santa Ana Mountains.

Out on the coastline and up along the foothills and mountains, you may discover for yourself Orange County’s place in the natural world. An hour or less of driving and less than two hours’ walk will take you from the frenetic city to any of several interesting natural environments, ranging from tidepools to fern-bedecked canyon streams to mountain peaks affording views stretching a hundred miles. You’ll discover fascinating rock formations, rich and varied plant life, a healthy population of native animals, and a sense of peace and tranquility.

In the next few pages, you’ll learn briefly about the “other” Orange County: its climate, geology, flora, and fauna. Following that, you’ll find some notes about safety and courtesy on the trail and some tips on how to get the most out of this book. After perusing that material, you can dig into the heart of this book—descriptions of 124 hiking routes from the coast to the Santa Ana Mountains. Happy reading and happy hiking!

Land of Gentle Climate

A succinct summary of Orange County’s climate might take the form of just two phrases: “warm and sunny” and “winter-wet, summer-dry.” But some variation in climate exists across the county’s width from coast to mountain crests. Without resorting to technical classification schemes, let’s divide the county into two climate zones: The coastal zone, extending inland 10–15 miles across the coastal plain and low coastal foothills, is largely under the moderating influence of the Pacific Ocean. This climate is characterized by mild temperatures that are relatively stable, both daily and seasonally. Average temperatures range from the 60s to 40s (daily highs and lows in Fahrenheit) in winter to the 70s to 60s in summer. Rainfall averages about 15 inches annually. Overall this climate closely matches the classic Mediterranean climate associated with coastal areas along the Mediterranean Sea.

The inland zone, consisting of the Santa Ana Mountains and foothills, experiences somewhat more extreme daily and seasonal temperatures because it is less influenced by onshore flows of marine air. The higher summits of the Santa Ana Mountains, for example, have average temperatures in the 50s to 20s in winter, and the 80s to 50s in summer. Precipitation averages about 30 inches annually in the higher Santa Anas, which is just enough to support natural pockets of coniferous and broadleaf trees, such as pines, oaks, and maples. Almost every year, some fraction of the precipitation arrives in the form of snow, which briefly blankets the mountain slopes down to an elevation of about 3,000 feet.

Despite its reputation for a gentle climate, Orange County is occasionally subject to hot, dry winds called “Santa Ana winds” (after Santa Ana Canyon, just north of the Santa Ana Mountains). These winds occur when an air mass moves southwest from a high-pressure area over the interior United States out toward Southern California. As the air flows downward toward the coast, it compresses and becomes warm and dry. Low passes in the mountains or river valleys that act as wind gaps (such as Santa Ana Canyon) funnel these desertlike winds toward the coast. During stronger Santa Anas, common in late summer and fall, Orange County basks under warm, blue skies swept clear of every trace of pollution (except possibly smoke from wildfires). Temperatures along the coast can then reach record-high levels; the city of Orange, for example, once recorded a temperature of 119 degrees during a Santa Ana.

Rainfall in Orange County is as erratic as it is slight. On the coastal plain, the annual precipitation has ranged from merely 4 inches to a record of 32 inches. Up to 5 inches have fallen on the coastal plain in a single day, and in the Santa Ana Mountains, one storm dumped 9 inches in a single night.

By and large, Orange County’s balmy, dry climate is remarkably well suited to year-round outdoor activity. Nevertheless, high temperatures, scarcity of water, and occasionally smoggy air during summer and early fall make that particular period less desirable for hiking in the inland foothills and mountains. During the other seven or eight months of the year, the weather is often ideal.

Reading the Rocks

Of California’s many geomorphic (natural) provinces, Orange County claims parts of only two: the Los Angeles Basin and the Peninsular Ranges. The bulk of the county’s urbanized area lies in the Los Angeles Basin, while the mostly undeveloped Santa Ana Mountains and the semideveloped San Joaquin Hills belong to the Peninsular Ranges province.

The Los Angeles Basin province extends from the base of the San Gabriel and Santa Monica Mountains (part of the Transverse Ranges province) to the north to the base of the Santa Ana Mountains and the San Joaquin Hills on the south. In a geologic context, it can be pictured as a huge, deeply folded basin filled to a depth of up to 7 miles by some volcanic material and land-laid sediments, but mostly by sediments of marine origin—sand and mud deposited on the ocean bottom from 80 million years ago to as recently as 1 million years ago.

The Los Angeles Basin area has experienced uplift during the past 1–2 million years, and as this took place, the surface of the basin accumulated a layer of terrestrial sediment shed from the surrounding hills and mountains. The basin, in fact, would still be filling up with sediment were it not for the flood-control dams and channeled riverbeds that have largely replaced the original meandering Santa Ana, San Gabriel, and Los Angeles Rivers.

Cloud-walking, Laguna Bowl Road (see Chapter 4)

Hikers following this guidebook will discover many interesting and sometimes colorful exposures of marine sedimentary rocks in places like the Chino Hills, San Joaquin Hills, and foothills of the Santa Ana Mountains. These sediments, uplifted by a variety of geologic processes, are continuations of the formations that lie deep underground in the center of the Los Angeles Basin.

The marine sediments you will see—sandstone, siltstone, shale, and conglomerate—tend to be rather soft and easily eroded. Along the south coast, where the San Joaquin Hills meet the sea, several wave-cut “marine terraces” are identifiable on the coastal headlands. They exhibit a record of changing sea levels and gradual uplift over the past 1–2 million years. In many places, the terraces themselves are deeply cut by drainage channels—the coastal canyons—which themselves are quite recent features.

The Santa Ana Mountains, along with the San Jacinto Mountains, lie at the northwest tip of the extensive Peninsular Ranges province, stretching south toward the tip of Baja California (the province, in fact, derives its name from Baja’s peninsular shape). Each range in this province possesses a core of granitic (granitelike) rock, overlain in many places by a veneer of older metamorphic rocks. Many of the Peninsular Ranges, including the Santa Anas, are raised and tilted fault blocks, typically with steep east escarpments and more gradually inclined western slopes.

As you travel through the Santa Ana Mountains (and their distinctly named subdivisions, the Elsinore and the Santa Margarita Mountains), you’ll begin to piece together their geologic history. Starting at, say, Caspers Wilderness Park in the foothills and moving up toward the crest of the Santa Anas, you first pass among light-colored marine sedimentary rock formations that were pushed up and tilted by the rise of the mountains to the east. Next comes metamorphic rock of two basic kinds—metasedimentary and metavolcanic. These brown- or gray-colored rocks, roughly 200–150 million years old, are metamorphosed (changed by heat and pressure) forms of marine sedimentary and volcanic rock that were plastered against the core of the North American continent some tens of millions of years ago. These rocks were riding on one or more of the Earth’s tectonic plates, which collided with and were subducted (forced under) the western edge of the continent.

Near the crest of the Santa Ana Mountains, you find light-colored granitic rocks. Here’s the reason: About 100 million years ago, when the subduction process was in full swing, much of the material on the edge of the plate being subducted melted underground and accumulated in the form of vast pools of magma. Because this magma was less dense than the surrounding materials, it rose toward the surface. Some escaped through volcanoes, but most of it remained underground long enough to slowly cool and crystallize, forming coarse-grained “plutonic” (generally granitic) rocks. Erosion then nibbled away at the overlying metamorphic rocks, finally exposing—typically in high places—the granitic rocks.

In the southern Santa Anas and throughout most of California’s share of the Peninsular Ranges, this granitic rock is now well exposed. In the northern Santa Anas, however, its distribution is less extensive. The highest peaks in the range, Santiago and Modjeska Peaks (together called Old Saddleback), are still covered by older, overlying metamorphic rocks.

The granitic rocks are still rising, more than offsetting the leveling effects of erosion. Thus, although the rocks of the Santa Ana Mountains range between old and ancient, the origin of the range itself as a structural unit is quite recent.

Of more than casual interest to Orange Countians is the fact that for at least the past 10 million years, the Peninsular Ranges province (along with the present Los Angeles Basin and a wedge of coastal central California) has been drifting northwest relative to the rest of the North American continent. In a global view, this motion is seen as a lateral sliding (or rather a repeated lurching) at the interface between the largely oceanic Pacific Plate and the largely continental North American Plate. The average rate of movement in the early 21st century is about 2 inches per year—enough, if it continues, to put Orange County abreast of San Francisco 12 million years from now.

The famous San Andreas Fault (which runs about 40 miles northeast of Orange County) is the principal division between the two plates. But earth movement can also take place along splinter faults south and west of the San Andreas. One such splinter fault, the Elsinore Fault, passes along the eastern base of the Santa Ana Mountains. Horizontal and vertical movements along this fault over the past 5 million years have shifted the Santa Ana Mountains northwest relative to the adjacent landforms to the east, and have raised and tilted the whole mountain block into its characteristic west-sloping orientation. Sudden earth movements along any of these faults have been and will again be responsible for most of Southern California’s devastating earthquakes.

The geologic history of Orange County is a fascinating one, and the diversity of landforms and rocks in Orange County and the Santa Ana Mountains is enough to pique the curiosity of most any amateur geologist. Refer to Appendix 2 for sources of additional information.

Native Gardens

About 800 different kinds of wild flowering plants are found within Orange County’s 782 square miles, a remarkably large number considering its diminutive size among California counties.

There are two reasons for this abundance of plant species. One reason has to do with physical factors: topography, geology, soils, and climate. Countywide, the diversity of physical factors and the complex interrelationships among these factors have led to the existence of many kinds of biological habitats.

The second reason is Orange County’s location between two groups of flora: a southern, drought-tolerant group, most clearly represented by various forms of cacti; and a northern group, represented by moisture-loving plants typical of California’s northern and central Coast Ranges. As the climate changed, varying from cool and wet to warm and dry over the past million years or so, species from one group and then the other invaded the county. Once established, many of these species persisted in protected niches even as the climate turned unfavorable for them. Some survived unchanged; others evolved into unique forms. Some are present only in very specific habitats.

The bulk of Orange County’s undeveloped land can be grouped into three general classes, which botanists often call plant communities or plant associations. In a broader sense, they are biological communities because they include animals as well as plants. These plant communities are briefly described below.

The sage scrub (or coastal sage scrub) community lies mostly below 2,000 feet in elevation and extends east from the coastline to the foothills and lower spurs of the Santa Ana Mountains. The dominant species are small shrubs, typically California sagebrush, black sage, white sage, and wild buckwheat. Two larger shrubs often found here are laurel sumac and lemonade berry, which like poison oak are members of the sumac family. Interspersed among the somewhat loosely distributed shrubs is a variety of grasses and wildflowers, green and colorful during the rainy season but dry and withered during the summer and early-fall drought.

The chaparral community is commonly found above 2,000 feet in the Santa Ana Mountains, where it cloaks the slopes like a thick-pile carpet. The dominant plants are chamise, scrub oak, manzanita, mountain mahogany, toyon, and various forms of ceanothus (“wild lilac”). These are tough, intricately branched shrubs with deep root systems that ensure their survival during the long, hot summers. Chaparral is sometimes referred to as an “elfin forest,” a literal description of a mature stand. Without the benefit of a trail, travel through mature chaparral, which is typically 10–15 feet high, is almost impossible. Sage scrub and chaparral vegetation tend to intermix readily throughout the Santa Anas, the chaparral preferring shadier, north-facing slopes, and the sage scrub preferring hot, dry, south-facing slopes.

The southern oak woodland community is found in scattered locations throughout the county, from the bigger coastal canyons in the San Joaquin Hills to moist flats and canyons throughout the Santa Ana Mountains. Within the Orange County area, the indicator tree is the live oak, but sycamores may also be abundant. In the Chino Hills, native walnut trees form a major component of the southern oak woodland community. Beneath the trees, various chaparral and sage scrub plants often form a sparse understory.

Aside from these three widespread natural communities, much of the nonurbanized land in and around Orange County is given over to agriculture and grazing. Areas characterized by heavy grazing have grassy flats and bald slopes called potreros (pastures) supporting mostly nonnative grasses and herbs, such as wild oats, filaree, mustard, and fennel.

To a small extent, several other natural communities are found in Orange County: rocky shore, coastal strand, coastal salt marsh, freshwater marsh, riparian woodland, and coniferous forest.

The riparian (streamside) woodland community, existing in discontinuous strips along some of the bigger watercourses, is perhaps the most biologically valuable. Not only is this kind of environment essential for the continued survival of many kinds of birds and animals, it is also very appealing to the senses. Massive sycamores, cottonwoods, and live oaks and a screen of water-hugging willows are the hallmarks of the riparian woodland. Most of this habitat has already been usurped by urbanization and the development of water resources.

The coniferous (cone-bearing-tree) forest community was once more widespread in the Santa Ana Mountains. The west-side canyons were logged a century ago in connection with various short-lived mining booms; this logging and subsequent wildfires have reduced the forest to small, isolated patches that cling to the slopes of the deeper canyons. Bigcone Douglas-fir and Coulter pine are the indicator species of coniferous forest in the Santa Anas, although live oaks and other broadleaf trees are also frequently present.

A few species of plants of limited geographic extent in the county are worth noting:

Knobcone pine, somewhat widely distributed in the northern and central California Coast Ranges and the foothills of the Sierra Nevada, clings to a small toehold in the Santa Ana Mountains on the slopes of Pleasants Peak. Here, it finds the warm, dry climate and the particular kind of soil—serpentine—it thrives on.

Bigleaf maple, California bay (bay laurel), and madrone, found in the west-side canyons of the Santa Ana Mountains, are three more examples of trees at or close to the southern end of their natural range. The madrones are restricted to a tiny area in upper Trabuco Canyon.

The Tecate cypress, once widespread throughout Southern California, is now confined to small arboreal islands in San Diego County, in northern Baja California, and along the slopes of Coal and Gypsum Canyons in the northern Santa Anas (just outside the Cleveland National Forest boundary). Here, it finds the extra moisture, in the form of nocturnal fogs moving in from the coast, that it needs in order to hold onto its biological niche.

Late winter to mid-spring is the best time to appreciate the cornucopia of Orange County’s native plants. Many of the showiest species—the annual wildflowers—burgeon at this time, and other plants exhibit fresh, new growth. For more information about the wildflowers, shrubs, trees, and other flora typically found in Orange County, see Appendix 2.

Creatures Great and Small

Your first sighting of an eagle, mountain lion, badger, or any other seldom-seen form of wildlife is always a memorable experience. Because of the diversity of the still-natural parts of Orange County, they are host to a healthy population of indigenous creatures, including a few rare and endangered species. If you’re willing to stretch your legs a bit and spend some time in the areas favored by wild animals, you’ll eventually be rewarded by some kind of close visual contact.

While doing fieldwork for an earlier edition of this book, Jerry Schad was lucky to spot a young mountain lion while hiking in the Santa Ana Mountains, and a golden eagle while driving on Interstate 5 through the hills of south county.

The most numerous large creature in Orange County is the mule deer, with a population of perhaps several hundred. These deer prefer areas of forest and chaparral, especially at higher elevations in the Santa Anas.

The mountain lion, once hunted to near-extinction in California, has made a comeback as a protected species. Perhaps two dozen lions now roam the remote canyons of the Santa Ana Mountains and foothill areas. Counting them is difficult, since mountain lions have a large territorial range (up to 100 square miles) and are normally very secretive. Because of their wide-ranging travels, however, tracks and other signs of them are quite frequently seen.

The county’s mammals also include the coyote, which has adapted to a broad range of habitats, including the margins of suburbia; the bobcat, a creature sometimes mistaken for a mountain lion, but smaller and more common and with a short bobtail rather than the lion’s 3-foot tail; the gray fox; skunk; opossum; raccoon; ringtail cat; badger; and various rabbits, squirrels, bats, woodrats, and mice.

Among the more commonly seen reptiles are rattlesnakes, discussed later under “Special Hazards.”

The richness of birdlife in the Orange County area is impressive, not only because of the diversity of its habitats, but also because the county lies along the Pacific Flyway route of spring–fall bird migration and serves as a wintering area for waterfowl. Several species of rare or endangered birds nest or visit, including the southern bald eagle, peregrine falcon, lightfooted clapper rail, least tern, Belding’s savannah sparrow, and least Bell’s vireo.

Fire Ecology

Chaparral and sage scrub have evolved to burn periodically. Many species have highly flammable resinous leaves, and many have underground root burls that survive moderately intense fire and resprout shortly afterward. Some species depend on occasional fires to reproduce, and many “fire follower” wildflowers grow only after a wildfire. Before humans impacted the area, lightning-induced fires typically burned any given acre every 30–150 years.

The arrival of humans has greatly impacted these plant communities. People and cattle have brought a number of invasive species, especially mustard and nonnative grasses. These plants grow vigorously in the spring, then die and dry up in the summer, adding vast amounts of tinder for fires. People have also increased the frequency of ignition; downed power lines, vehicle accidents, careless smokers and campers, kids with matches, and malicious arsonists have all caused major fires in Southern California.

Deep inside Water Canyon, Chino Hills State Park (see Chapter 7)

As a result, wildfires have become much more frequent in Southern California. In 1993, Orange County became keenly aware of its fire risk as the Ortega Fire incinerated 21,010 acres around Highway 74 and the Laguna Beach Fire swept through Laguna Canyon, burning 14,337 acres and 336 homes. From 2006 to 2008, the Sierra Fire and Santiago Fire burned major portions of the Santa Ana Mountains and western foothills, and then the Freeway Complex Fire swept across almost all of Chino Hills State Park. Fires have become so frequent in some areas that plants may not be able to reestablish themselves before the next wave arrives, threatening to cause permanent ecological changes in which the native sage scrub is replaced by even more flammable invasive weeds.