WASO Review Draft, 9/25/2007

Natural Resource Significance National Park Service Natural History Themes Preliminary Draft, September 2007 represented in the national park system and in The National Park Service (NPS) uses four basic areas that have been designated National Natural criteria to evaluate the national significance of Landmarks. proposed areas. These criteria, listed in the National Park Service Management Policies, state The National Natural Landmarks Program that a resource is nationally significant if it meets recognizes and encourages the conservation of all of the following conditions: outstanding examples of our country's natural 1. It is an outstanding example of a particular history. It is the only natural areas program of type of resource. national scope that identifies and recognizes the 2. It possesses exceptional value or quality in best examples of geological and biological illustrating or interpreting the natural or features in both public and private ownership. cultural themes of our nation's heritage. National Natural Landmarks (NNLs) are designated 3. It offers superlative opportunities for public by the Secretary of the Interior, with the owner's enjoyment, or for scientific study. concurrence. As described later in this section, 4. It retains a high degree of integrity as a true, several areas in the study area were accurate, and relatively unspoiled example of recommended for NNL status in previous studies. a resource. The full thematic framework is described in the National Park Service professionals, in consultation publication, “Natural History in the National Park with subject matter experts, scholars, and System and on the National Registry of Natural scientists determine whether a study area is Landmarks” (NPS 1990). The themes are nationally significant. evaluated by two criteria: 1) significance and 2) adequacy of representation within the national park system. Natural History Themes The National Park Service uses a series of themes This section evaluates the significance of study to evaluate potential areas for inclusion in the area natural resources according to the NPS national park system. These themes are part of a thematic framework for natural history. classification system developed by the National Park Service to identify natural history themes

View of the San Gabriel Mountains from the Puente-Chino Hills 1 WASO Review Draft, 9/25/2007

Overview of Natural Resource National Significance Landforms of the Present Themes Mountain Systems

ƒ The San Gabriel Mountains are among the fastest growing mountains in the world. Forces from the San Andreas Fault to the north and a series of thrust faults on its south face are causing the San Gabriel Mountains to rise at a rate of up to 2 inches a year, thus serving as an excellent location to learn about mountain building.

ƒ One of the most geologically diverse mountain ranges in Southern California, the San Gabriel Mountains are comprised of rocks from all of the major geologic eras. This includes the most extensive, best-exposed and most completely studied exposures of several geologic formations: the San Gabriel Mountains anorthosite massif, the Mount Lowe plutonic suite, and Pelona schist.

ƒ Some of the oldest rocks (over one billion years old) on the west coast of the United States are located in the San Gabriel Mountains. Rocks of this age are typically found farther east in association with the oldest parts of the North American continent.

ƒ The complex geologic formations of the San Gabriel Mountains serve as a “Rosetta stone” for understanding the evolution of the earth’s ancient crust and the younger San Andreas Fault system.

ƒ There is a long history of scientific study of the San Andreas Fault in southern California. Several historically significant geologic discoveries occurred in the San Gabriel Mountains. Geologists continue to use the San Gabriel Mountains in their quest to better understand the continuing evolution of the dynamic and rapidly changing southern California landscape.

Sculpture of the Land

ƒ The dramatic change in elevation coupled with striking landforms such as the Devil’s Punchbowl provides a highly scenic landscape of contrasts.

River Systems and Lakes

ƒ River systems within the San Gabriel Mountains meet the eligibility criteria for National Wild and Scenic River designation. Free-flowing sections of Little Rock Creek and the north, east and west forks of the San Gabriel River retain high levels of integrity and support sensitive wildlife. Portions of these river systems traverse the San Gabriel and Sheep Mountain Wilderness Areas providing opportunities for public enjoyment in a wilderness setting. The east and west forks of the San Gabriel River contain remarkable recreational values and provide easy access to year-around water-based recreation.

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Land Ecosystems Themes

Chaparral and Dry Coniferous Forest

ƒ The topographically and geologically diverse landscape provides habitat for ecological communities with an abundance of endemic and rare plants and animals.

ƒ Outstanding examples of southern California communities are located in the study area including California walnut woodlands and forests, bigcone Douglas-fir, relict juniper communities, coastal sage scrub, and subalpine habitat. With high concentrations of such specimens in the San Gabriel Mountains, Puente-Chino Hills, and other undeveloped open spaces, this mosaic of residual native plant communities provides refuge for threatened and endangered species and is an excellent display of southern California’s natural heritage.

ƒ The San Dimas Experimental Forest in the Angeles National Forest provides superlative opportunities for the scientific study of mountain watersheds and chaparral ecosystems. Data collected in the San Dimas Experimental Forest since 1933 represents some of the earliest and most comprehensive records from continuously monitored experimental watersheds in the United States. In 1976, the United Nations Educational, Scientific and Cultural Organization’s (UNESCO) Man and the Biosphere Program recognized the San Dimas Experimental Forest as a “Biosphere Reserve.”

Aquatic Ecosystems Themes

Streams

ƒ Angeles National Forest lands and other undeveloped open space areas within the study area contain some of the last remaining, intact alluvial fan and riparian communities in the Los Angeles Region.

ƒ Significant riparian areas and alluvial fan vegetation provide a refuge for many rare, threatened and endangered plant and wildlife species.

3 WASO Review Draft, 9/25/2007 Landforms of the Present tectonically active mountain systems in the United The “Landforms of the Present” theme describes the States. Tectonic activity along regional faults is forcing character of the landscape as a physical and scenic the mountains to rise at a rate of as much as 2 inches entity as it exists today, as well as present and past a year (Murphy 1985). Large events such as the geologic events and processes. Principal features of Sylmar earthquake of 1971 (6.6 magnitude) have the natural landscape such as mountain systems, river resulted in the San Gabriel Mountains rising six feet in systems and lakes are included in this theme. Each relation to the San Fernando Valley floor (Norris and landform possesses certain distinguishing qualities and Webb 1990). characteristics which set it apart from others. The Measured as a function of the horizontal distance following sub-themes related to Landforms of the from the ocean, these mountains present the greatest Present are represented in the study area: vertical elevation gain from the ocean when compared to anywhere else in the continental United States. The ƒ Mountain Systems: San Gabriel Mountains proximity of mountains to the sea presents unique ƒ Sculpture of the Land: Devil’s Punchbowl climatic conditions and orographic effects, causing ƒ River Systems and Lakes: East, West and large amounts of annual rainfall and significant North Forks of the San Gabriel River, Little flooding (McPhee 1989; Gumprecht 1999). Rock Creek Geologic Diversity Mountain Systems: San Gabriel One of the most geologically diverse mountain ranges in Southern California, the San Gabriel Mountains are Mountains comprised of rocks from all of the major geologic eras The San Gabriel Mountains are part of the Transverse as defined by the U.S. Geological Survey’s geologic Range geomorphic province which includes mountains time scale. This includes the most extensive, best- along the southern California coastline that lie east- exposed and most completely studied exposures of west or “transverse to” the prevailing northwest- several geologic formations: the San Gabriel trending character of the North American Pacific Mountains anorthosite massif, the Mount Lowe margin. Other mountain systems in this province plutonic suite, and Pelona schist. include the Santa Ynez Mountains, the Santa Monica Mountains, the San Bernardino Mountains and the San Gabriel Anorthosite Massif. Anorthosite, a off-shore mountains of the Channel Islands. To the plutonic rock formed from molten masses that cooled north lies the Mojave Desert province and to the south slowly underground, is a distinctive ancient rock in the and west lies the Peninsular Range province. The San western San Gabriel Mountains. The San Gabriel Gabriel Mountains comprise approximately two-thirds anorthosite is one of only two large anorthosite of the 700,000-acre study area. massifs1, in the United States (the other is in the Adirondack Mountains in New York). The only other Active Mountain Building California exposures are located in the Orocopia The steepest and most rugged of all the southern Mountains of Riverside County and in Joshua Tree California mountain systems, the San Gabriel National Park. These smaller areas of anorthosite are Mountains are a scenic backdrop to the Los Angeles remnants of the large massif in the San Gabriel Region. The San Gabriel Mountains owe their Mountains. ruggedness to the fact that they are one of the most

Left: San Gabriel Mountains, Right: Arrows show areas where thrust faults have lifted the San Gabriel Mountains foothills (Altadena)

1 A massif is a large mountain mass or compact group of connected mountains forming an independent portion of a range. 4 WASO Review Draft, 9/25/2007

Left: Anorthosite exposure; Right: Mt. Lowe Pluton

Anorthosites are best exposed in the San Gabriel first sample of anorthosite from the lunar surface. Mountains. There they exhibit nearly all of the Referred to as the “Genesis Rock” this sample characteristic lithologies, structures and textures of confirmed the theory that the lunar surface was once other anorthosite massifs, and they have not been completely molten. subjected to regional metamorphism. Thus they provide a superlative opportunity to study rocks of the Mt. Lowe Plutonic Suite. The Triassic Mount Lowe anorthosite association (Powell 2007b; Carter 1982a; plutonic suite has helped geologists understand the Norris and Webb 1990). development of the west coast’s great mountains systems. During the Mesozoic era (248-65 million Anorthosite in the San Gabriel Mountains is also of years ago), the Pacific Plate collided with the North interest because this rare rock type, which is common American Plate forming a volcanic arc along the on the moon, helped to prove the theory of how the continental margin (Barth and Wooden 2006). This lunar landscape formed. Apollo 15 astronauts trained volcanic arc formed what is now referred to as the for geologic lunar missions in anorthosite regions of Cordillera. The Cordillera defines the backbone of the San Gabriel and Orocopia Mountains in the early mountains that run along western North America. It is 1970s. Scientists needed to find samples of the area of North America that has experienced the anorthosite on the surface of the Moon to prove the most mountain building in modern geologic times theory that the Moon was once molten, and formed (Lillie 2005). layers of different density rock and metal as it cooled. The Apollo 15 crew who visited the San Gabriel Primarily comprised of feldspar, the pluton is divided Mountains to learn about anorthosite collected the into four compositional zones based on the appearance of hornblende, potassium feldspar, garnet and biotite (Joseph et al 1982). The typical appearance of these rocks is white with black spots (biotite). Given its appearance it is sometimes referred to as the “Dalmatian rock.”

With its distinctive composition and age, the Mt. Lowe plutonic suite is unique not only in southern California, but throughout the Cordillera. Only small fragments of the Mt. Lowe plutonic suite exist in other areas of Southern California.

Vincent Thrust and Pelona Schist. The Vincent Thrust and associated Pelona schist has played a particularly important role in understanding regional geology in southern California. A thrust fault is a particular type of fault, or break in the fabric of the Earth's crust in which layers from below are thrust up and over Anorthosite sample acquired by the Apollo 15 crew. The another as a result of compressional forces. media called this sample the “Genesis Rock.”

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Left: Pelona Schist; Right: Augen Gneiss The Vincent Thrust has been viewed as the most Only in the San Gabriel Mountains are rocks of this important structural feature in the Transverse Range age found so close to the geologically young, western Province (Ehlig 1982). The Vincent Thrust brought two coast. Rocks of this age are typically associated with separate rock masses together approximately 99 to 65 what geologists refer to as the North American million years ago (USGS 2007). This event was not Craton. The North American Craton is the old nucleus confined to rocks now exposed in the San Gabriel of the North American continent. Most of interior Mountains but is likely a regionally-developed zone Canada and the United States are included in the that underlies much of the Transverse Ranges and craton. Ancient rocks associated with the craton are Mojave Desert provinces of southern California (USGS typically found in national parks throughout the 2007). Midwest and in the Colorado Plateau (areas of Utah, Colorado, Arizona and New Mexico where the craton The Vincent Thrust structurally juxtaposes two distinct has been uplifted). Ancient rocks associated with the sets of basement rocks in the San Gabriel Mountains. craton are critical to understanding the geologic The western San Gabriel Mountains basement rocks history of North America (Powell 2007b; Lillie 2005; consist primarily of ancient crystalline rocks associated USFS 2005; Norris and Webb 1990). with the upper plate of the Vincent Thrust. Eastern San Gabriel Mountains basement rocks are associated with the lower plate consisting primarily of metamorphosed sedimentary and volcanic rocks known as the Pelona schist. Rocks that constitute the Pelona Schist were originally deposited well off-shore along the continental margin of North America. The Vincent Thrust pushed these off-shore rocks into the continental margin. The best area to observe the Vincent Thrust is in the eastern San Gabriel Mountains high country between Mount San Antonio and Mount Baden-Powell (Ehlig 1982).

Ancient Rocks The San Gabriel Mountains contain some of the oldest granitic and metamorphic rocks in California. Ancient Precambrian rocks in the San Gabriel Mountains include Mendenhall gneiss (1.045 billion years old), anorthosite and related rocks (1.02 billion years old) and augen gneiss (1.7 billion years old). Although these rocks are not as old as the 3.6 billion-year old Archean rocks of the Lake Superior region, they do form part of the Precambrian core of the North American continent. (Norris and Webb 1990, Powell

2007b) Ancient rocks typically associated with the oldest part of North America (the craton) are located in the San Gabriel Mountains. The yellow area depicts the younger mountains and coastal plains of the west coast. The purple areas are portions of the craton that were deformed by plate collisions. 6 WASO Review Draft, 9/25/2007 Plate Tectonics and the San Andreas Fault The theory of plate tectonics suggests that large features on the earth’s surface, such as continents, ocean basins, and mountain ranges, result from interactions along the edges of large plates of the earth’s outer shell (see figure 1).

These plates rest on the warm, soft layer of the earth’s mantle allowing movement of the plates. Motions between the plates form several types of plate boundaries: convergent, divergent and transform. Divergent boundaries are where plates are pulled apart. Volcanoes typically occur in these areas. Convergent boundaries are where one plate slides beneath another (subduction). Transform boundaries are where plates slide past one another (Lillie 2005).

The San Andreas Fault System formed along the transform Figure 1: Plates of the Earth, NPS boundary between the North American and Pacific Plates. Along the boundary, the Pacific Plate is moving northwestward past the North American Plate at a rate of up to 5 centimeters a year. At this rate, thousands of years from now the City of Los Angeles will have moved north to where the City of San Francisco exists today (See Figure 2).

Active movement along the transform boundary results in earthquakes, large lateral displacements of rock, and crustal deformation. All along the San Andreas Fault, great deformation occurs from the grinding between the two plates. This deformation is very apparent in aerial photographs of California (See Figure 3).

Deformation along the San Andreas Fault is responsible in part for the active mountain-building of the San Gabriel Mountains. Figure 4 shows how the combination of the San Andreas Fault, in concert with other regional faults is both displacing and uplifting the San Gabriel Mountains.

Figure 2: San Andreas Fault – Transform plate boundary, As one of the few places of on Earth where a transform- USGS fault plate boundary occurs on land rather than beneath the sea, the San Andreas Fault System is one of the most studied structural geologic features on the planet. Research in the San Gabriel Mountains has made significant contributions to such studies.

Figure 3: Deformation along the San Andreas Fault Zone. Figure 4: The structure of the San Andreas Transform Fault Plate Boundary in relation to the San Gabriel Mountains, USGS

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The San Andreas Fault and Plate Tectonics Early Studies of Plate Tectonics. Famous geologist Levi Just north of the San Gabriel Mountains lies the San Noble was the first to advance ideas about large-scale Andreas Fault. The San Andreas Fault is a geological lateral movement along the San Andreas Fault. In the structural feature that stretches roughly 800 miles early 20th century Noble had a ranch in Valyermo, on along the west coast of the United States. Arguably the San Andreas Fault just north of the San Gabriel the most well-known and significant geological Mountains. Here, Noble engaged in a long-term study feature along the west coast of the continental United of a fifty-mile stretch of the San Andreas Fault near States, this fault system has played an important in the San Gabriel Mountains (Norris and Webb, Wright role in our understanding of plate tectonics . and Troxel, 2002).

A History of Geologic Study. There is a long history of Noble published his findings in 1927 as part of the scientific study of the San Andreas Fault in southern Carnegie Institute of Washington Yearbook No. 25. California. Several historically significant geologic This landmark paper contains the first printed discoveries occurred in the San Gabriel Mountains. The statement that lateral displacement occurred along the San Gabriel Mountains were the first location where: San Andreas Fault for many miles. In it Noble observes, “Scarcely anywhere in the fault zone are the rocks on ƒ Large lateral movements on the San Andreas Fault the opposite sides of the master fault similar (Wright were noted; and Troxel 2002).” The concept was an important precursor to later ideas regarding plate tectonics ƒ Geologists discovered the Vincent Thrust and (Carter 1982b). related Pelona schist and recognized its regional significance; Although later studies have shown displacement to be much greater than he thought, Noble’s ideas were an ƒ Geologists began particular studies in important early component in the evidence that led to paleoseismicity (the study of prehistoric our appreciation of the role of the San Andreas Fault earthquakes) to reconstruct the frequency of in the theory of plate tectonics. significant prehistoric earthquakes on the San Andreas Fault. These studies help geologists make predictions on the timing of future significant events on the San Andreas Fault.

Figure 5: The location of geological features associated with the San Gabriel Mountains has helped geologists understand plate movement along the San Andreas Fault. The red arrows indicate the relative movement of the plates along the San Andreas Fault (Based on Powell 1993). 8 WASO Review Draft, 9/25/2007

Evolution of the San Andreas Fault. The complex geologic formations of the San Gabriel Mountains serve as a “Rosetta stone” or a key for understanding the evolution of the San Andreas Fault in southern California.

The rare and unique geologic units of the San Gabriel Mountains have helped geologists to determine how the San Andreas Fault evolved and shaped the southern California region. Figure 5 demonstrates how related fragments of San Gabriel Mountains geologic units provide insight into the rate of movement along the San Andreas fault (Powell 2007b). Remnants of the Vincent Thrust Fault and the associated Pelona schist are located in the Orocopia and Chocolate Excavation at Pallett Creek - Note the contrasting layers of Mountains, located 150 miles to the south on the sediment in the excavation. These layers of charcoal and opposite side of the San Andreas Fault in Riverside and peat were analyzed and radiocarbon dated to determine Imperial Counties. Correlations between Pelona schist the frequency of major earthquake events on this portion associated with the Vincent Thrust and the Chocolate of the San Andreas Fault. and Orocopia Mountain Thrusts indicate that the central Transverse Ranges have been displaced by 150 and through use of radiocarbon dating, it was to100 miles (estimates vary) of movement along the determined that the frequency of past earthquakes main trace of the San Andreas Fault. along this segment of the fault recur at an interval of about 150 years (Sieh 1984). Cross fault correlations with other distinct units such as anorthosite, rocks of the Mt. Lowe plutonic suite, At the far northeastern end of the study area, more augen gneiss, Cenozoic sedimentary and volcanic analysis of stratigraphic horizons of peat and charcoal rocks, and the debris shed from these distinctive units at Wrightwood have rendered more specific have further strengthened this type of analysis. When information on the frequency of past earthquakes on all of these geologic features are taken into this section of the San Andreas Fault (Weldon, Fumal, consideration, the overall displacement has been and Biasi 2004). estimated to be as much as 195 miles (Norris and Webb 1990; Ehlig 1982; Nourse 2002; Powell 1992 Opportunities for Public Enjoyment in San and 1993). This body of information continues to Gabriel Mountains grow as geologists learn more about the complex San The San Gabriel Mountains provide a wide range of Gabriel Mountains geologic units. opportunities for public enjoyment. One of the most visited national forests in California (and the United Paleoseismic Studies. Paleoseismic studies examine States); this landscape of contrasts provides geologic units and landforms to identify records of recreational opportunities for millions of visitors each prehistoric earthquakes. Evidence of prehistoric year. earthquakes can include faulted layers of sediment and rock, injections of liquefied sand, landslides, Geological formations and features can be accessed abruptly raised or lowered shorelines, and tsunami and seen from the Angeles National Forest trail deposits. Identification of earthquakes through time systems, which include the Pacific Crest National helps geologists understand the timing of major Scenic Trail and four national recreational trails. Some prehistoric earthquakes. This type of analysis also helps of the most scenic hikes in the San Gabriel Mountains geologists begin to make assumptions about the are also superlative places to learn about geological timing of future significant earthquakes. processes. Examples include trails through the Devil’s Punchbowl, the hike to Mount San Antonio, and the By analyzing layers of charcoal and peat in creek beds hike along the east fork of the San Gabriel River to and sag ponds along the San Andreas Fault, geologists “the narrows.” The narrows is one of the best places have been able to estimate the frequency of major to see examples of Pelona Schist associated with the earthquake events on the San Andreas Fault. One of Vincent Thrust. Many of the unique geological the first sites where this type of research was features can also be viewed in road cuts along the conducted in California was Pallet Creek, located in Angeles Crest Scenic Highway and the Antelope Antelope Valley, near Devil’s Punchbowl County Park. Freeway. Pallet Creek runs across the San Andreas Fault. By The portion of the San Andreas Fault that traverses the studying the patterns of peat and charcoal deposits study area is also the location of the highest elevation 9 WASO Review Draft, 9/25/2007 point along the San Andreas Fault. In the northeastern Most areas along the San Andreas Fault are filled with corner of the study area near the Big Pines area of the sediments, alluvium or water (in the case of sag Angeles National Forest, one can see the deep and ponds) which makes such gaps less obvious. The high wide crevasse at the plate boundary. The deep point is thus an excellent location to interpret this crevasse highlights the magnitude of activity important geologic feature. associated with the transform plate boundary. Other mountain recreational opportunities include hiking, backpacking, camping, swimming, rock climbing, picnicking, birding, fishing, off-highway vehicle driving and horseback riding.

Left: Jackson Lake, a natural sag pond on the San Andreas Fault is a popular recreation area in the Angeles National Forest; Right: Pacific Crest Trail access, Angeles National Forest.

10 WASO Review Draft, 9/25/2007 Sculpture of the Land: Devil’s Punchbowl protect national forest resources with scenic, historical, The scenic Devil’s Punchbowl consists of magnificently geological, botanical, zoological or other special exposed ridges and ravines etched into steeply tilted characteristics. Devil’s Punchbowl is managed by both and folded sandstone that protrudes out of the the Angeles National Forest and Los Angeles County surrounding substrate. Located between within the Parks. Devil’s Punchbowl County Park features a San Andreas and Punchbowl Fault Zones, the Devil’s variety of opportunities for education and public Punchbowl was down-dropped into areas of older enjoyment including a natural history museum, trails, crystalline rocks. picnic areas and camping, group tours and school programs (USFS 2005). The Devil’s Punchbowl was identified by two previous studies as a significant geological feature (NPS 1974 River Systems and Lakes: East, West and and NPS 1976). The latter study recommended it for North Forks of the San Gabriel River and designation as a National Natural Landmark. It was Little Rock Creek described as “an ideal place to ponder the importance Many river systems in the San Gabriel Mountains of the regional faults and to view the San Gabriel remain free-flowing with intact riparian areas. The U.S. Mountains (NPS 1976).” Forest Service conducted an assessment of these rivers

while completing the 2005 Angeles National Forest The pinkish red weathered rocks are an excellent Plan. The U.S. Forest Service analysis determined that exposure of the Miocene Punchbowl Formation. free-flowing stretches of the East, North and West Adding to this area’s interest is a scenic riparian area, Forks of the San Gabriel River and Little Rock Creek a tributary of Little Rock Creek. This area provides are eligible for National Wild and Scenic River nesting habitat for the prairie falcon. Devil’s designation. Punchbowl remains in a natural condition and is designated a “Special Interest Area” by the Angeles Congress enacted the Wild and Scenic Rivers Act in National Forest. Special interest areas are managed to 1968 to ensure that certain selected rivers which possess outstandingly remarkable scenic, recreational, geologic, fish and wildlife, historic, cultural or other similar values, would be preserved in free-flowing condition. The determination of whether a river area contains "outstandingly remarkable values" is a professional judgment on the part of the study team and is documented in a report, management plan, or other planning document.

The U.S. Forest Service found the North Fork of the San Gabriel River to have outstandingly remarkable values for native fish species such as the Santa Ana sucker, Arroyo chub, and Santa Ana speckled dace. It also has remarkable wildlife values providing suitable habitat for federally listed threatened and endangered species such as the mountain yellow-legged frog, California red-legged frog, California gnatcatcher, and the least Bell’s vireo.

The East Fork of the San Gabriel River contains outstandingly remarkable values for recreation, native fish assemblages and cultural resources. The East Fork is the only major river corridor that traverses the Sheep Mountain Wilderness Area. The naturally flowing river in a wilderness setting has significant recreational value. Similar to the North Fork, the East Fork also has a significant assemblage of native fish species. Unique to the East Fork are cultural resources associated with mining sites related to Native American, Spanish and early American settlement. Devil’s Punchbowl

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The West Fork of the San Gabriel River runs along the geological features in the San Gabriel Mountains southern border of the San Gabriel Wilderness Area. continues to provide major contributions to our Outstandingly remarkable recreation values include understanding of plate tectonics. access to wilderness, camping and high quality fishing The San Gabriel Mountains provide an ideal setting to opportunities. A National Recreation Trail and National learn about mountain building and plate tectonics. Scenic Bikeway follows much of the river course. Close proximity to the Los Angeles Metropolitan Area provides that many universities and colleges alike with The West Fork has the largest assemblage of native readily available access to the mountains. Geologists fish habitats in the Angeles National Forest. It is one have studied the San Gabriel Mountains for many of the only streams in southern California managed as years and continue to make new discoveries and new a Wild Trout Stream and contains habitat for the Santa theories about the evolution of the San Andreas Fault Ana sucker and the Arroyo chub. The West Fork and the Transverse Range Province. offers some of the best opportunities for fishing in the Los Angeles Region. Both the East Fork and West Fork The San Gabriel Mountains form a scenic backdrop of offer opportunities for public enjoyment in a the Los Angeles Region. One of the most visited wilderness setting. national forests in California, this landscape of contrasts provides recreational opportunities for Little Rock Creek sustains indigenous wildlife millions of visitors each year. populations including federally listed threatened and Geological formations and features can be accessed endangered species such as the mountain yellow- and seen from the Angeles National Forest roads and legged frog and the arroyo toad. Portions of upper trail systems. Little Rock Creek remain in an undisturbed and primitive condition (USFS 2005). Upper reaches of the San Gabriel River and Little Rock Creek have significant wildlife and recreational opportunities that meet the criteria for National Wild The biggest recreational draw for these rivers is the and Scenic River designation. These rivers retain high access to water-based recreation throughout the year. levels of integrity and offer superlative opportunities These opportunities are rare in the Los Angeles for public enjoyment and learning about wildlife Region. Demand for these opportunities will only habitat and historic mining activity. increase as the regional population continues to grow at a pace that far outweighs the creation of new areas for recreation. This has resulted in overcrowding and impacts to easily accessible portions of the San Gabriel River upper tributaries.

Summary: The San Gabriel Mountains are among the most tectonically active systems in the world. These rugged mountains contain outstanding examples of geological features that represent rock types from almost all of the major geological eras.

One of the first places where crustal movement along the San Andreas Fault was noted, scientific study of

Left: East Fork San Gabriel River; Right: West Fork San Gabriel River

12 WASO Review Draft, 9/25/2007 Land Ecosystems Themes The steep terrain and early recognition of its The theme “Land Ecosystems” represents vegetation importance for watershed protection has prevented types as well as the animal populations and physical development from spreading to the San Gabriel environmental features which are often important Mountains. The San Gabriel Mountains were set aside elements in identifying and evaluating sites. The as one of California’s first forest reserves in 1891 in an following sub-themes related to Land Ecosystems are effort to protect the mountains from agricultural represented in the study area: pressure, industrial growth, and other activities that modified the landscape. California forest reserves pre- date national forest designations and represent an ƒ Chaparral (shrubs and evergreen forest early step in the evolution of the American trees): Coastal sage scrub, San Dimas conservation movement. Experimental Forest (chaparral) ƒ Dry Coniferous Forest: California walnut Although certain areas of the Angeles National Forest woodlands, bigcone Douglas-fir, pinyon- have been altered for flood control and recreational juniper forest, subalpine forest facilities, as a whole, the native plant communities remain intact and provide a refuge for wildlife.

The topographically and geographically diverse study area contains an array of plant communities that span two ecological regions (ecoregions), the coastal Southwestern ecoregion, which includes coastal areas from Santa Barbara County to San Diego County, and the Mojave Desert ecoregion. Plant communities range from coastal sage scrub in the coastal valleys and foothills, to unique subalpine habitats high in the San Gabriel Mountains, to desert scrub and Joshua trees at the northern base of the mountains.

Due to extensive urbanization in the Los Angeles Region, many of these native communities and associated wildlife are now rare, threatened or endangered. Southern California has been identified as a “hotspot” for biodiversity due to the high diversity of imperiled species (Stein, Kutner and Adams 2000). The intersection of biological resources and urbanization has made the southern California coastal region the most-threatened biologically diverse area in the continental United States (California Department of Fish and Game 2007).

In 1973 the National Park Service conducted a comprehensive survey of natural history in California and identified sites with national significance that would be eligible for the National Natural Landmarks Program. This survey found that for areas in the The Puente Hills Transverse and Peninsular Ranges, “Much of the The Puente Hills in the Los Angeles Basin contain a mountainous areas lack intensive agriculture or dense diversity of native plant communities. Although this urbanization unlike the lowland valleys and flood area is somewhat of an island of open space within plains of this area. These upland sites are in many urbanized areas, the Puente Hills along with the Chino cases the sole remnant of the pristine landscape (NPS Hills and the Santa Ana Mountains (see Map: 1973).” Topography) to the southeast together encompass about 511,000 acres of wildlands containing This statement remains true today. The native plant significant biological resources (Noss, Beir and Shaw communities within the study area are concentrated in n.d.). This mountain system is associated with the the San Gabriel Mountains and foothills, in active Whittier-Elsinore Fault System. Maintaining this undeveloped hillsides areas such as the Puente and contiguous corridor is a high priority for state and local San Jose Hills, and in significant riparian areas along conservation agencies. river corridors.

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Figure 3: The graphic above depicts land-cover for the study area (USGS 2001 National Land-Cover Database). Gray areas indicate developed areas (about 25% of the study area) with darker grays being the most intensely developed. Yellow and greens areas are open space. Dark green represents forest cover, while lighter green represents shrub communities. The lightest green indicates developed open space such as parks. Yellow areas are grasslands and orange/brown areas represent agricultural areas. Important open space corridors and connections are outlined with a dashed blue line.

While the Puente Hills Landfill Native Habitat nevinii) (FE), slender-horned spineflower Preservation Authority manages almost 4,000 acres in (Dodecahema leptoceras) (FE), Braunton’s milk- the western Puente Hills, large areas of privately vetch (Astragalus brauntonii) (FE), thread-leaved owned land in the eastern Puente Hills provide key brodiaea (Brodiaea filifolia) (FT), and California linkages and connections to the larger wildlife Orcutt grass (Orcuttia californica) (FE). corridor. These linkages are important for the wildlife that relies on this corridor. ƒ Federally listed threatened or endangered The diverse range of plant communities in the study animals include the arroyo toad (Bufo area provide habitat for 66 plant species considered californicus) (FE), least Bell’s vireo (Vireo bellii sensitive, rare, threatened or endangered. Of these 66 pusillus) (FE), mountain yellow-legged frog species, 51 are endemic. A high concentration of (Rana muscosa) (FT), unarmored threespine wildlife is also present in the study area. The study stickleback (Gasterosteus aculeatus williamsoni) area provides habitat for approximately 133 wildlife (FE), California condor (Gymnogyps species considered sensitive, rare, threatened or californianus) (FE), bald eagle (Haliaeetus endangered (See Tables A2 and A3 in the Natural leucocphalus) (FT), California red-legged frog Resource Description Appendix). (Rana aurora draytonii) (FE), coastal California gnatcatcher (Polioptila californica californica) (FT), Of these sensitive plant and animal species, 16 are desert tortoise (Gopherus agassizi) (FT), Santa federally listed threatened (FT) or endangered (FE) Ana sucker (Catostomus santaanae) (FT) and species. southern willow flycatcher (Empidonax traillii ƒ Federally listed threatened or endangered extimus) (FE). plants include: Nevin’s barberry (Berberis 14 WASO Review Draft, 9/25/2007

Outstanding examples of remaining southern California plant communities are located in the study The study area contains a wide range of coastal sage area. The following section describes native plant scrub communities not typically represented in any communities in the study area that contribute to its one protected area in southern California. Three significance. These habitats include coastal sage scrub, classifications of coastal sage scrub are typical of the chaparral, California walnut woodlands and forests, Southwestern ecoregion as classified by Axelrod: bigcone Douglas-fir forest, relict juniper forests, Venturan, Riversidian, And Diegan. A fourth subalpine communities, alluvial sage scrub and riparian representation, Coastal sage scrub-chaparral, typically areas. found in transitional areas near mountain foothills has been defined by Holland. All four variations are represented in the study area. Riversidian coastal sage Chaparral scrub is primarily located in the upper Santa Clara Coastal Sage Scrub River watershed. Venturan is found in the San Jose Coastal sage scrub is found at elevations below 2,500 Hills, Puente Hills and San Gabriel Mountains foothills. feet in climates with mild temperatures and maritime Diegan coastal sage scrub is found in the eastern influence. Shrubs are knee-high with soft flexible Puente Hills. The Puente Hills represent a transition leaves that are often drought-deciduous. The most between Venturan and Diegan coastal sage scrub common species associated with coastal sage scrub is (Puente Hills Landfill Native Habitat Preservation California sagebrush (Artemisia californica). Authority 2007; Davis, et al. 1994, Axelrod 1978).

Coastal sage scrub is one of the most threatened plant Coastal sage scrub habitat is protected by the Angeles communities in California. Since 1945 the majority of National Forest, the Puente Hills Landfill Native Habitat coastal sage scrub vegetation in California has been Preservation Authority, and a few other local and lost to urban and agricultural land use (Kirkpatrick and regional open space areas. The northern extent of the Hutchinson 1980). Only 15% of coastal sage scrub’s Northern Orange County Natural Community historic range remains in southern California. This Conservation Program (NCCP) is located within the habitat is of the highest priority for preservation (Davis study area. The NCCP is a voluntary program designed et al. 1998, Mistretta 2007, personal communication, to conserve natural communities at the ecosystem NPS 1973). scale while accommodating compatible land use (California Department of Fish and Game, 1993).

Within the study area, coastal sage scrub is found in Although current efforts to protect coastal sage scrub the San Gabriel Mountains foothills, the Soledad Basin have focused on areas in Orange, Riverside, and San and the Montebello, San Jose and Puente Hills. Many Diego Counties, the NCCP identified the San Jose, rare, threatened and endangered species are Puente Hills and foothill areas of the San Gabriel associated with this habitat including the federally Mountains as a functioning biological unit of high listed threatened California coastal gnatcatcher, the conservation value for coastal sage scrub. federally listed threatened thread-leaved brodiaea and

the federally listed endangered Nevin’s barberry Areas managed by the National Park Service that (Stephenson and Calcarone 1999). Designated critical protect coastal sage scrub in the Southwestern habitat areas for the California coastal gnatcatcher ecoregion include primarily Venturan (Santa Monica within the study area include the Puente Hills, the San Mountains National Recreation Area and Channel Jose Hills, the San Gabriel Mountain foothills from Islands National Park) and Diegan (Cabrillo National Glendora east to Claremont, and the western San Monument) distributions. Gabriel Mountains foothills near the City of Santa Clarita (65 Federal Register No. 25, February 7, 2000).

Left: Original stream gauge developed at SDEF, 1941; Right: Aerial view of the SDEF 15 WASO Review Draft, 9/25/2007

Coastal sage scrub typically forms in scattered patches includes the Fern Canyon Research Natural Area. mixed in with other plant communities. In areas where coastal sage scrub is located with other native plant The San Dimas and Dalton watersheds were chosen communities, there are superlative opportunities to for the innovative experimental forest because the interpret the natural history of the Los Angeles vegetation pattern was typical of Mediterranean Metropolitan Area. watersheds; the area was separated from the rest of “When combined with other habitat types in the area, the San Gabriel Mountains by the San Gabriel and San such as chaparral and oak/sycamore woodland, the Antonio Canyons forming isolated watersheds; and vegetation provides habitat for a unique assemblage because of the ability to control water flow with newly of plants and animals (Puente Hills Landfill Native constructed flood control facilities (Robinson 1985). Habitat Preservation Authority 2007).” Some of the most important areas of SDEF research Some of the coastal sage scrub communities within include: the study area are located in regional parks and ƒ Recognition and quantification of the hydrological recreation areas that provide opportunities to enjoy cycle in chaparral watersheds. and learn about this plant community. Recovery and ƒ Manipulations in limiting erosion and increasing research areas include coastal sage scrub habitat water yield. managed by the Claremont College Bernard Field ƒ Botanical observations about the ecology of Station in the San Gabriel Foothills and the Northern chaparral. Orange County NCCP subregion. ƒ Ground-breaking work in pedogenesis or soil evolution. San Dimas Experimental Forest (Chaparral ƒ Biochemical assays on soil and plant tissues. ecosystem) ƒ Post-fire plant and animal succession and Established in 1933, the San Dimas Experimental recovery. Forest (SDEF) is one of the oldest experimental forests ƒ Information on pollution loading. Scientists have in the nation. Created as a natural laboratory to study been able to compare the build up of heavy fire, hydrology, and other topics related to chaparral metals in soils to that of soils in the 1930s ecology, the SDEF maintains some of the earliest and (Wohlgemuth 2007, Jones and Stokes 2003). most comprehensive records from continuously monitored experimental watersheds in the United Technological innovations in watershed research States (Jones and Stokes 2003). In 1976, the United include the development of rain gauges and rain Nations Educational, Scientific and Cultural gauge networks to accurately measure precipitation in Organization’s (UNESCO) Man and the Biosphere steep terrain, the development of flumes (San Dimas Program recognized the SDEF as a “Biosphere Flume) to measure and withstand debris-laden flows, Reserve.” the identification of post-fire soil conditions and use of lysimeters, large rectangular planters, which are used The San Dimas Experimental Forest was established to to measure the influence of different vegetation types determine the value of chaparral and associated on water transpiration, evaporation and percolation. forests for watershed protection and to provide a basis The SDEF contains the largest and most complete for management to obtain the maximum beneficial lysimeter installation in existence (Robinson 1985; yield of water. The SDEF covers over 17,000 acres and Robinson 1991).

Left: Walnut woodlands, Puente Chino Hills; Right: Bigcone Douglas-fir, San Gabriel Mountains

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Bigcone Douglas-Fir Forests Although not open to the general public, scientists Bigcone Douglas-fir is a native evergreen conifer from universities and other institutions continue to use closely associated with canyon live oak (Quercus the SDEF for experimental studies. “Few other chrysolepis) where it emerges above the oak canopy mountain areas of comparable size on earth have (Howard 1992). been as thoroughly and painstakingly examined as has the San Dimas Experimental Forest” (Robinson 1985). Bigcone Douglas-fir occurs in the mountains of southern California. It is distributed from the Santa Dry Coniferous Forest Ynez Mountains in eastern Santa Barbara County and the Tehachapi Mountains of southwestern Kern California Walnut Woodlands and Forest County south to Julian, San Diego County (Howard California walnut (Juglans californica) woodlands and 1992). Although bigcone Douglas-fir populations are forests are typically associated with California’s currently stable, distribution in the Transverse and southern oak woodland communities. Stands range Peninsular Ranges has been impacted by extreme fire from savannas to forests. Contiguous stands once events. The Falls Canyon Research Natural Area of the lined the Puente-Chino and San Jose Hills favoring Angeles National Forest, a tributary of the West Fork shale soils that have a high water-holding capacity. of the San Gabriel River, preserves rare stands of Walnut woodlands and forests provide habitat for dense, mature bigcone Douglas-fir trees, some of deer, nesting birds, and rodents. which are over 350 years old.

California walnut woodland communities are in Old-growth stands of bigcone Douglas-fir are rare. decline and residual stands are extremely limited. The Most communities are in decline as younger trees do best remaining stands of California walnut-dominated not survive well during the extreme fire events forests and woodlands south of Ventura County are common in the San Gabriel Mountains. The Falls located in the San Jose and Puente-Chino Hills. Canyon forest is more resistant to fire because of its lack of understory vegetation. According to the California Natural Diversity Database (CNDDB), walnut forests are only found in small The Forest Service manages Falls Canyon Research patches in Ventura and Los Angeles County. Forests in Natural Area to maintain biological diversity and the study area represent the southern limit of walnut provide ecological baseline information, education, forests although a few patches of walnut woodlands and research. Falls Canyon is located on the slopes of are located in areas as far south as North San Diego Mount Wilson and is accessible from Mount Wilson County. Road. Various trails border and traverse the region providing opportunities for public enjoyment and to The CNDDB has on record approximately 17,000 acres learn about these old-growth forests. of remaining California walnut woodlands and forests. Approximately 2,300 acres are located in the study Relict Pinyon-Juniper Habitat area. Only a small percentage (8%) of the California Although pinyon-juniper communities are common in walnut woodlands and forests within the study area southern California, a community near Mescal Creek, are in public ownership (CNDDB 2006). Some of the which flows from the San Gabriel Mountains north to prime examples are currently in private ownership in the Mojave Desert, contains an unusual relict/remnant the Puente Hills. (Quinn 1990). juniper woodland. The type of vegetation found in this woodland is a remnant of vegetation that was In 1973, a National Park Service study identified a prevalent in this area during the Pleistocene epoch grove of walnut woodlands in Diamond Bar as a (1.8 million - 8,000 years ago.) With its adjacency to potential National Natural Landmark (NPS 1973). Mescal Creek and the varied topographic relief of the Although this particular woodland has been reduced area, this woodland also has high aesthetic value somewhat by development, woodlands and forests in (National Park Service 1973). nearby Brea and Tonner Canyons remain outstanding examples of the dry coniferous forest sub-theme Fossils of similar woodland species associated with the (Quinn 1990; Los Angeles County 2000). Pleistocene Epoch have been found in the La Brea Tar Pits in Los Angeles. Species include Juniperus Publicly owned and accessible walnut woodlands and californica and Juniperus utahensis. The Mescal Creek forests can be found in Chino Hills State Park, Bonelli juniper woodland was recommended for National Regional Park, Walnut Park, Puente Hills Landfill Native Natural Landmark status in a previous study because Habitat Preservation Authority lands, and on lands of the high aesthetic value and the opportunity it owned by the California State Polytechnic University in provides to interpret the interaction of geologic Pomona. history, plant geography, plant adaptation, water

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supply, desert-montane habitat and ecotones importance of these remaining ecological communities (National Park Service 1973). will become more significant. Managed by the Angeles National Forest, there are few trails in the Mescal Creek Area and off-road The San Dimas Experimental Forest in the Angeles vehicle use is not allowed. It is primarily managed for National Forest provides superlative opportunities for research and educational purposes (National Park the scientific study of mountain watersheds and Service 1973). chaparral ecosystems. Data collected in the San Dimas Experimental Forest represents some of the earliest Subalpine Habitat and most comprehensive records from continuously Mount San Antonio and Mount Baden-Powell in the monitored experimental watersheds in the United San Gabriel Mountains contain a rich array of isolated States. Technological innovations used to monitor the subalpine habitats in close proximity to large-scale arid experimental forest’s watersheds are in use in similarly and semi-arid landscapes. diverse areas all over the world.

Mount San Antonio, the highest peak in the San Although many easily accessible areas have Gabriel Mountains (10,064 ft), contains a variety of experienced impacts from recreation and other uses, rare alpine and subalpine plants, partly related to the early conservation efforts such as the preservation of local geology. The area supports an unusual subalpine the San Gabriel Timber Reserve in 1891 and the forest of krummholz lodgepole pine, Pinus murrayana. inaccessibility of the interior portion of the San Gabriel Disjunct western juniper (Pinus occidentalis ssp. Mountains have helped retain a high degree of australis) also occurs here. integrity for many of the plant communities there. The combination of these resources makes this area a Mount San Antonio is the only known locality in superlative place to interpret the natural heritage of southern California for the rare dwarf hawksbeard southern California. (Crespis nana), an arctic-alpine plant species. Other rare plant species in this area include alumroot (Heuchera abramsii), bed straw (Galium parishii), and wooly mountain parsley (Oreonana vestita). The area provides summer habitat for Nelson’s bighorn sheep, a California Species of Special Concern. The area was recommended as a potential National Natural Landmark in a 1979 survey (Martin 1979, USFS 2005).

Mt. Baden-Powell, at 9,399 feet, features some of the best examples of 1,000 year-old limber pines in southern California. The peak and adjacent area contain elements of subalpine habitat, including at least three endemic plant species (USFS 2005).

The U.S. Forest Service manages Mount Baden-Powell and Mount San Antonio as two separate special interest areas. Public enjoyment opportunities compatible with protecting these special characteristics are encouraged. Hikes to Mount San Antonio and Mount Baden-Powell are popular attractions of the Angeles National Forest.

Summary: The topographically and geologically diverse landscape of the study area provides habitat for a wide range of ecological communities with an abundance of species considered rare, threatened and endangered. Outstanding specimens of native plant communities in southern California are located in the study area. While not every plant community discussed would be considered nationally significant on its own, Ancient Limber Pine at Mt. Baden-Powell the combination of these resources represents the mosaic of southern California’s natural heritage. As this highly urbanized region continues to develop, the 18 WASO Review Draft, 9/25/2007 Aquatic Ecosystems Themes species diversity and the San Gabriel River was among The theme “Aquatic Ecosystems” is based on one of two sites that exhibited the greatest structural geomorphic and other physical aspects of aquatic diversity (Hanes et al. 1989). ecosystems. The sub-theme “Streams” represents aquatic ecosystems with flowing waters. The following A 1976 National Park Service study recommended the sub-themes related to Aquatic Ecosystems are alluvial fan sage scrub vegetation at the Santa Fe represented in the study area: Recreation Area site for designation as a National Natural Landmark. The study found this example to be ƒ Streams: Alluvial fan sage scrub, riparian representative of a plant community that was habitat historically important to settlers and Native Americans.

Streams Alluvial fan sage scrub is also found in San Dimas Alluvial Fan Sage Scrub Wash, Tujunga Wash and along the upper Santa Clara Alluvial fan sage scrub is a distinct and rare plant River. Some of the best examples of biologically intact community found on alluvial fans and floodplains desert alluvial fan sage scrub are found associated along the southern base of the Transverse Ranges and with Little Rock and Big Rock Creeks in the Antelope portions of the Peninsular Ranges in southern Valley (Los Angeles County 2000). California. Sometimes known as floodplain sage scrub, this habitat generally consists of a mixture of shrubs Rare and sensitive plants and animals inhabit alluvial which colonize and persist within infrequently scoured fan sage scrub including the federally listed and flooded terrain such as floodplains, alluvial plains, endangered slender-horned spineflower and the or along seasonal streams. The dominant shrub in federally listed endangered San Bernardino kangaroo most washes is scalebroom and many of the common rat. species are similar to those found in coastal sage scrub and chaparral communities (Hanes et al 1989). Alluvial fan vegetation in the Santa Fe Dam Recreation Area can be seen while hiking along the self-guided Alluvial fan sage scrub was once abundant in river nature trails near the Nature Center. San Antonio washes throughout the Los Angeles Basin before it Canyon alluvial fan sage scrub is primarily located was significantly reduced by flood control projects, within the San Antonio Spreading Grounds. These agriculture, and development projects (Davis et al. lands are owned and managed by the Pomona Valley 1998). Today, only remnants of this habitat remain in Protective Association. Because they function as a the Los Angeles Region. San Antonio Canyon, Big groundwater recharge area they are not open to the Tujunga Wash and the Santa Fe Dam Recreation Area public. Some of the San Antonio Canyon alluvial fan on the San Gabriel River contain some of the last sage scrub is owned by the Claremont University remaining well-developed stands of alluvial fan sage Consortium, primarily for research purposes. scrub (Hanes et al. 1989). Riparian Vegetation An analysis of ten stands of the most well-developed A wide range of riparian habitats are present within alluvial fan vegetation in Los Angeles, Riverside and the study area including Mojave riparian forest, San Bernardino Counties found that Big Tujunga Wash southern coast live oak riparian forest, southern was one of three sites which exhibited the most cottonwood willow riparian forest, southern mixed

Left: Alluvial Fan Sage scrub at Santa Fe Dam Recreation Area in Irwindale; Right: Riparian Habitat along the San Gabriel River

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riparian forest, southern riparian scrub, and southern residents flock to the perennially flowing rivers during sycamore alder riparian woodland (Davis et al. 1998). the dry season. As previously discussed in the section Remaining intact riparian habitat with high integrity is on river systems, demand for water-based recreation is primarily located in the San Gabriel Mountains and increasing. foothills and along the upper San Clara River. Summary: River and stream systems in the Los In the San Gabriel Valley and Los Angeles Coastal Angeles Region have been highly altered by flood Plain, riparian areas exist along river corridors and in control systems and development projects. Angeles the Puente-Chino Hills. It is estimated that National Forest lands and other undeveloped open approximately 75% of the historical riverine areas space areas within the study area contain some of the associated with the lower San Gabriel River has been last remaining, intact alluvial fan and riparian lost to urbanization and alterations for flood communities in the Los Angeles Region. These protection. Greatest losses have occurred in the communities are a refuge for many rare, threatened Whittier Narrows area (Stein et al. 2007). Surrounding and endangered plant and wildlife species. development and flood control structures have impacted Whittier Narrows. It is estimated that 80% Recreation areas with aquatic systems are among the of the riparian areas at Whittier Narrows contain the most desired places for recreation. Aquatic resources highly invasive giant reed, Arundo donax. in the study area are not only important for their wildlife and recreational values, but they also provide Despite losses of habitat in the Los Angeles Basin, precious water supplies for Los Angeles Region. The remaining riparian areas support a high diversity of study area aquatic systems provide superlative wildlife including threatened and endangered species. opportunities to interpret the importance of southern The Whittier Narrows Dam County Recreation Area California aquatic systems. riparian habitat supports over 300 migratory and resident bird species. This area, along with several other Los Angels County Flood Control Basins, is recognized as “Important Bird Area” by Birdlife International. Also recognized as an International Bird Areas are the Santa Fe Dam Recreation area and the Santa Clara River both of which support a high number of bird species associated with riparian habitat (Los Angeles County Department of Public Works 2006; Audubon Society 2007; San Gabriel and Lower Los Angeles Rivers and Mountains Conservancy 2001).

The upper Santa Clara River in the Soledad Basin contains high quality riparian and aquatic habitat that support the Santa Ana sucker, arroyo toad, unarmored threespine stickleback and the southwestern willow- flycatcher. The Santa Clara River is the only major river in southern California that runs freely without obstruction by major flood protection facilities. This area also functions as one of the important habitat linkages in the Los Angeles Region providing a connection between the San Gabriel and Castaic Mountains (Stephenson and Calcarone 1999).

Rivers and creeks in the San Gabriel Mountains support well-developed riparian areas with high levels of integrity. These rivers and creeks are a refuge for a number of threatened and endangered native aquatic species including the arroyo chub, threespine stickleback, Santa Ana sucker, mountain yellow- legged frog and arroyo toad.

Riparian areas available for public enjoyment receive heavy amounts of use, particularly in the more easily accessible areas of the Angeles National Forest. Area

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Summary Table Natural Resource Significance

Natural History It is an outstanding example of a It possesses exceptional value or It offers superlative opportunities for It retains a high degree of integrity Themes: particular type of resource quality in illustrating or public enjoyment, or for scientific study as a true, accurate, and relatively Landforms of the interpreting the natural or cultural unspoiled example of a resource Present themes of our nation's heritage Mountain Systems: The San Gabriel Mountains are The San Gabriel Mountains provide an Close proximity to the Los Angeles Early conservation of the San Gabriel San Gabriel among the most tectonically active ideal setting to learn about mountain Metropolitan Area provides universities and Mountains in 1891 has preserved the Mountains systems in the world. building and plate tectonics. colleges alike with excellent access to the integrity of this important mountain mountains. system. The San Gabriel Mountains contain The San Gabriel Mountains contain outstanding examples of geological the most extensive, best exposed, and One of the most visited national forests in features that represent rock types most completely studied exposures of California, this landscape of contrasts provides from almost all of the major three geologic formations – the San recreational opportunities for millions of geological eras. Gabriel anorthosite massif, the Mt. visitors each year. Recreational opportunities Lowe plutonic suite, and the Pelona include hiking, backpacking, camping, Some of the oldest rocks (over one schist. swimming, picnicking, birding, fishing, off- billion years old) on the west coast of highway vehicle driving and horseback riding. the United States are located in the Geologists have studied the San San Gabriel Mountains. Rocks of this Gabriel Mountains for many years and Many of the unique geological features can be age are typically found farther east in continue to make new discoveries viewed from mountain trails and road cuts association with the oldest parts of about the evolution of the San along the Angeles Crest Scenic Highway and the North American continent (the Andreas Fault and the Transverse the Antelope Freeway. craton). Range Province. A scenic backdrop of the Los Angeles Region, the San Gabriel Mountains offer dramatic views of both the coast and the desert. Sculpture of the The Devil’s Punchbowl is a Located in the San Andreas Rift Zone, Managed by Los Angeles County Department The area remains in natural condition. Land: Devil’s magnificently exposed ridge of steeply Devil’s Punchbowl is an ideal place to of Parks and Recreation, Devil’s Punchbowl Devil’s Punchbowl is designated a Punchbowl tilted sandstone that was forced out ponder the importance of the regional features a natural history museum, trails, “Special Interest Area” by the Angeles of areas of older crystalline rocks by faults and to view the San Gabriel picnic areas and camping, group tours and National Forest and is managed as a tectonic activity. Tilted sandstone Mountains. school programs. county park by the Los Angeles ridge and associated riparian areas County Department of Parks and create a landscape with high scenic Recreation. value. River Systems and The U.S. Forest Service determined These river segments contain The east and west San Gabriel River tributaries The eligible river segments all retain Lakes: East, West that the upper reaches of the San outstandingly remarkable scenic, eligible for National Wild and Scenic River high levels of integrity. Continued high and North Forks of Gabriel River and Little Rock Creek are recreation, fish, wildlife and historic status contain outstandingly remarkable demand for water-based recreation in the San Gabriel River eligible for National Wild and Scenic resource values. recreational values. Little Rock Creek offers a the San Gabriel Mountains could and Little Rock River designation. high degree of potential for scientific study of affect the integrity of the upper Creek indigenous wildlife populations. reaches of the San Gabriel River.

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Natural History It is an outstanding example of a It possesses exceptional value or It offers superlative It retains a high degree of integrity Themes: Land particular type of resource quality in illustrating or interpreting opportunities for public as a true, accurate, and relatively Ecosystems the natural or cultural themes of our enjoyment, or for scientific unspoiled example of a resource nation's heritage study Chaparral: Coastal The study area contains a wide range of Only 15% of coastal sage scrub’s historic Coastal sage scrub communities In areas where coastal sage scrub is Sage Scrub coastal sage scrub communities. range remains in southern California. within the study area are located with other native plant concentrated in the San Gabriel communities, there are excellent This habitat is of the highest priority for protection and conservation and Mountains and foothills and in the opportunities to preserve some of the The Puente-Chino Hills are a transitional area represents an opportunity to preserve San Jose and Puente Hills. These remaining natural heritage of the Los for Venturan to Diegan coastal sage scrub southern California’s natural heritage. areas feature trails and recreational Angeles Metropolitan Area. communities. areas that provide access to learn about and enjoy these resources. The California Natural Community Conservation Program identified the In addition to Venturan and Diegan coastal San Jose, Puente Hills and foothill sage scrub communities that are typically areas of the San Gabriel Mountains as associated with coastal environments, the a functioning biological unit of high study area contains a significant amount of conservation value for coastal sage coastal sage scrub typically associated with scrub. interior valleys and mountain foothills (Riversidian coastal sage scrub). The northern extent of the Northern Orange County Natural Community Conservation Program is located within the study area. Chaparral: San Dimas Established in 1933, the San Dimas Studies completed at the experimental Although closed to the general The experimental forest has remained Experimental Forest Experimental Forest is one of the oldest forest have greatly contributed to our public, the San Dimas Experimental in continual use for scientific study experimental forests in the nation. Created as understanding of natural processes and Forest continues to be actively used since its inception in 1933. a natural laboratory to study fire, hydrology, chaparral ecosystems. for research. and other topics related to chaparral ecology, the SDEF maintains some of the earliest and Technological innovations developed at The San Dimas Experimental Forest most comprehensive records from the experimental forest to monitor in the Angeles National Forest continuously monitored experimental watersheds are in use in similarly diverse provides excellent opportunities for watersheds in the United States. areas all over the world. the scientific study of mountain watersheds and chaparral In 1976, the United Nations Educational, ecosystems. Scientific and Cultural Organization’s (UNESCO) Man and the Biosphere Program recognized the SDEF as a “Biosphere Reserve.” Dry Coniferous Forest: The best remaining stands of California California walnut woodland communities Publicly owned and accessible The slope, aspect and soil conditions California walnut walnut-dominated forests and woodlands are in decline and residual stands are walnut woodlands and forests can of the Puente-Chino Hills favor walnut woodlands south of Ventura County are located in the extremely limited. be found in Chino Hills State Park, woodlands and forest. Significant San Jose and Puente-Chino Hills. Although Bonelli Regional Park, Walnut Park, contiguous stands still line portions of walnut woodlands are found south of the Stands in the study area located in areas Puente Hills Landfill Native Habitat the Puente-Chino and San Jose Hills. study area, the Puente-Chino Hills contain the with other native plant communities Preservation Authority lands, and on

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Natural History It is an outstanding example of a It possesses exceptional value or It offers superlative It retains a high degree of integrity Themes: Land particular type of resource quality in illustrating or interpreting opportunities for public as a true, accurate, and relatively Ecosystems the natural or cultural themes of our enjoyment, or for scientific unspoiled example of a resource nation's heritage study southernmost extent of well-developed represent an excellent example of native lands owned by the California State California walnut forests. vegetation in the Los Angeles Basin. Polytechnic University in Pomona.

Dry Coniferous Forest: Falls Canyon Natural Research Natural Area in Given the increasing rarity of surviving The U.S. Forest Service manages Stands are dense, and more resistant Bigcone Douglas-fir the Angeles National Forest contains dense old-growth stands of bigcone Douglas- Falls Canyon Research Natural Area to fire than second-growth stands old growth forest stands of mature bigcone Douglas-fir trees, fir, the Falls Canyon Research Natural to maintain biological diversity and which are in decline. some of which are over 350 years old. Area provides exceptional value in provide ecological baseline illustrating this type of plant community. information, education, and research. Various trails border and traverse the region providing opportunities for public enjoyment and to learn about these old- growth forests.

Dry Coniferous Forest: Although pinyon-juniper forests are common This area was recommended for National The area has high aesthetic value Although developed recreation areas Relict Pinyon-Juniper in the Transverse Ranges and Mojave desert, Natural Landmark status in a previous with its adjacency to Mescal Creek are located south of the relict pinyon- Forest the Angeles National Forest features a relict study because of the high aesthetic value and varied topographic relief. The juniper forest, the area itself remains pinyon-juniper forest with rare and unusual and opportunity it provides to interpret site is adjacent to active recreation undisturbed with few trails. Off-road plant species. the interaction of geologic history, plant areas in the Angeles National vehicle use is not allowed. geography, plant adaptation, water Forest. supply, desert-montane habitat and ecotones. Dry Coniferous Forest: A previous National Natural Landmark Mount San Antonio and Mount Baden- Public enjoyment opportunities The U.S. Forest Service manages both Subalpine Forest evaluation of Mount San Antonio (10,064ft) Powell areas provide an opportunity to compatible with protecting these Mount Baden-Powell and Mount San stated that although Mount San Antonio is observe subalpine forest in close characteristics are encouraged. Antonio as special interest areas. not as high as Mount San Gorgonio above proximity to both desert and coastal Hikes to Mount San Antonio and Mount Baden-Powell is located in the Palm Springs (11,500ft), Mount San Antonio environments. Mount Baden-Powell are popular Sheep Mountain Wilderness Area. appears to have a richer array of isolated attractions of the Angeles National Because of these special management subalpine plants. Forest. designations, Mount Baden-Powell and Mount San Antonio retain a high Mt. Baden-Powell, at 9,399 feet, features level of integrity. some of the best examples of the 1,000 year- old limber pines in southern California.

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Natural History It is an outstanding example of a It possesses exceptional value or It offers superlative opportunities for It retains a high degree of integrity Themes: Aquatic particular type of resource quality in illustrating or interpreting public enjoyment, or for scientific study as a true, accurate, and relatively Ecosystems the natural or cultural themes of our unspoiled example of a resource nation's heritage Streams: Alluvial fan San Antonio Canyon and the Santa Fe Remnant vegetation at the Santa Fe Dam Alluvial fan vegetation in the Santa Fe Dam Large unspoiled river beds with alluvial sage scrub Dam Recreation Area on the San site was recommended as a National Recreation Area can be seen while hiking fan vegetation no longer exist in the Gabriel River contain some of the last Natural Landmark in a 1976 National along the self-guided nature trails near the Los Angeles Basin. However, small remaining examples of alluvial fan Park Service study as representative of a Nature Center. areas such as those at the base of the sage scrub. plant community that was historically San Gabriel Mountains continue to important to Native Americans and support a wide variety of reptiles and settlers. mammals. Streams: Riparian Intact riparian areas in the mountains Riparian areas in the study area support a Riparian areas available for public Although much of the riparian areas in habitat and foothills support a high diversity high diversity of wildlife including enjoyment receive heavy amounts of use, the Los Angeles Basin have been of wildlife including threatened and threatened and endangered species such particularly in the more easily accessible altered by development or flood endangered species. as the Santa Ana sucker, arroyo toad, areas of the Angeles National Forest. protection facilities, riparian areas in unarmored threespine stickleback and Several riparian areas in the Angeles the mountains and foothills still retain southwestern willow-flycatcher. National Forest were identified as having high quality habitat for many rare and outstandingly remarkable recreational endangered species. values.

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References

Axelrod, D.I. 1978 “The origin of coastal sage vegetation, Alta and Baja California.” In American Journal of Botany, v.65, no. 10, pp. 1117-1131.

Audubon Society 2007 Birds and Science: California Important Bird Areas (IBAs). Available online at: [http://iba.audubon.org/iba/stateIndex.do?state=US-CA.

Barth, Andrew P. and Joseph L. Wooden 2006 Timing of Magmatism following Initial Convergence at a Passive Margin, Southwestern U.S. Cordillera, and Ages of Lower Crustal Magma Sources. The Journal of Geology, volume 114 (2006), pp. 231–245

Carter, Bruce A. 1982a “Geology of the San Gabriel Anorthosite-Syenite Body, Los Angeles County, California.” In Fife, D. L., and Brown, A. R., (Editors). Geology and mineral wealth of the California Transverse Ranges: South Coast Geological Society, Mason Hill Volume, Annual Symposium and Guidebook Number 10. Santa Ana, CA: South Coast Geological Society.

Carter, Bruce A. 1982b “Early Geologic Studies of the Transverse Ranges, California.” In Fife, D. L., and Brown, A. R., (Editors). Geology and mineral wealth of the California Transverse Ranges: South Coast Geological Society, Mason Hill Volume, Annual Symposium and Guidebook Number 10. Santa Ana, CA: South Coast Geological Society.

California Department of Fish and Game 2007 California Wildlife: Conservation Challenges (Comprehensive Wildlife Conservation Strategy). Available online at: http://www.dfg.ca.gov/habitats/WDP/report.html (Accessed March 2007).

California Department of Fish and Game 2006 California Natural Diversity Database. Accessed October 2006. Available online at [http://www.dfg.ca.gov/bdb/html/cnddb.html].

1993 Southern California Coastal Sage Scrub NCCP Conservation Guidelines. Sacramento: California Department of Fish and Game.

Davis, F.W., Peter A. Stine and David M. Stoms 1994 “Applications of Remote Sensing and Geographic Information Systems for the Distribution and Conservation Status of Coastal Sage Scrub in Southwestern California.” In Journal of Vegetative Science, vol. 5, no. 5, pp. 743-756.

Davis, F.W., D.M. Stoms, A.D. Hollander, K.A. Thomas, P.A. Stine, D. Odionn, M.I. Borchert, J.H. Thorne, M.V. Gray, R.E. Walker, K. Warnter, and J. Graae 1998 The California Gap Analysis Project – Final Report. Santa Barbara, CA: University of California. Available on the internet at [http://gis.ucsc.edu/Projects/VWP/report.pdf]

Ehlig, Perry L. 1982 “The Vincent Thrust: Its Nature, Paleogeographic Reconstruction Across the San Andreas Fault and Bearing on the Evolution of the Transverse Ranges, San Gabriel Mountains.” In Fife, D. L., and Brown, A. R., (Editors). Geology and mineral wealth of the California

25 WASO Review Draft, 9/25/2007

Transverse Ranges: South Coast Geological Society, Mason Hill Volume, Annual Symposium and Guidebook Number 10. Santa Ana, CA: South Coast Geological Society.

Federal Register 2000, February 7. Endangered and Threatened Wildlife and Plants; Proposed Determination of Critical Habitat for the Coastal California Gnatcatcher. U.S. Fish and Wildlife Service. Vo.65, No. 25.

Gumprecht, Blake 1999 The Los Angeles River: Its Life, Death and Possible Rebirth. Baltimore: Johns Hopkins University Press.

Hanes, T. L., R.D. Friesen, and K. Keane. 1989 “Alluvial scrub vegetation in coastal southern California.” In Abell, Dana (Tech. Coordinator) Proceedings of the California Riparian Systems Conference: protection, Management, and Restoration for the 1990; September 22-24, 1988; Davis, California. Berkeley, CA: Pacific Southwest Forest and Range Experiment Station, Forest Service, U.S. Department of Agriculture.

Howard, Janet L. 1992 “Pseudotsuga macrocarpa.” In: Fire Effects Information System, U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available online at: [http://www.fs.fed.us/database/feis/ [2007, June 29].

Jones and Stokes 2003 Final Inventory and Evaluation Report for the San Dimas Experimental Forest, Los Angeles, California. Prepared for the United States Department of Agriculture Forest Service, Angeles National Forest. Arcadia, California.

Joseph, Stephen E. Joseph J. Criscione, Terry E. Davis and Perry L. Ehlig. 1982 “The Lowe Igneous Pluton.” In Fife, D. L., and Brown, A. R., (Editors). Geology and mineral wealth of the California Transverse Ranges: South Coast Geological Society, Mason Hill Volume, Annual Symposium and Guidebook Number 10. Santa Ana, CA: South Coast Geological Society.

Lillie, Robert J. 2005 Parks and Plates: The Geology of our National parks, Monuments and Seashores. New York: W.W. Norton and Company.

Los Angeles County Department of Public Works 2006 San Gabriel River Master Plan. Los Angeles County: Los Angeles County Department of Public Works.

McPhee, John 1989 The Control of Nature. New York: Farrar, Straus, Giroux.

Mistretta, Orlando 2007 Personal communication with Barbara Butler, National Park Service, Pacific West Region April 2007.

Murphy, Roy and Julia Murphy 1985 The San Gabriel Mountains. Arcadia, CA: Big Santa Anita Historical Society.

26 WASO Review Draft, 9/25/2007

National Park Service 1990 Natural History in the National Park System and on the National Registry of Natural Landmarks. Natural Resources Report, NPS NR NRTR-90/03. Washington, D.C.: National Park Service.

1979 A Survey of Potential Natural Landmarks, Biotic Themes, of the Mojave-Sonoran Desert Region. Prepared for the Heritage Conservation Recreation Service, United States Department of the Interior by Paul S. Martin. Tucson: University of Arizona.

1976 The Mojave-Sonoran Natural Region Study. Prepared for the National Park Service by Wachter, Bruce G., Bull, William B. and Stephen J. Reynolds. Tucson: University of Arizona, Department of Geosciences.

1973 Geological Resources of the South Pacific Border Region. Prepared for the National Park Service by John H. Lipps, James R. Correa, and Gary Zumwalt. Davis: University of California.

Noss, Reed, Beier, Paul and Shaw, William 1997 Evaluation Of The Coal Canyon Biological Corridor. Unpublished Report.

Nourse, Jonathan A. 2002 “Middle Miocene reconstruction of the central and eastern San Gabriel Mountains, southern California, with implications for evolution of the San Gabriel fault and Los Angeles Basin.” In Barth, A., ed., Contributions to Crustal Evolution of the Southwestern United States. Boulder, Colorado: Geological Society of America Special Paper 365, pp. 161-185.

Powell, Robert E., United States Geological Survey 2007 a Personal communication with Barbara Butler, National Park Service, Pacific West Region, September 2007.

Powell, Robert E., United States Geological Survey 2007a Personal communication with Barbara Butler, National Park Service, Pacific West Region, January 2007.

Powell, Robert E. 1993 “Balanced palinspastic reconstruction of pre-late Cenozoic paleogeology, southern California: Geologic and kinematic constraints on evolution of the San Andreas fault system” in Powell, R.E., Weldon R.J., and Matti, J.C. eds., The San Andreas Fault System: Displacement, Palinspastic Reconstruction, and Geologic Evolution. Boulder, Colorado, Geological Society of America Memoir 178, pp.1-106.

Powell, Robert E. and R.J. Weldon 1992 “Evolution of the San Andreas fault.” Annual Review of Earth and Planetary Sciences, v. 20, pp.431-468.

Puente Hills Landfill Native Habitat Preservation Authority 2007 Draft Resource Management Plan. Prepared by LSA Associates, Inc. for the Puente Hills Landfill Native Habitat Preservation Authority. Whittier, CA

Quinn, Ronald D. 1990 The status of walnut forests and woodlands (Juglans californica) in southern California. In: Schoenherr, Allan A., ed. Endangered plant communities of southern California: Proceedings, 15th annual symposium; 1989 October 28; Fullerton, CA. Special Publication No. 3. Southern California Botanists: Claremont, CA.

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Robinson, John 1991 The San Gabriels: The mountain country from Soledad Canyon to Lytle Creek. Arcadia, CA: Big Santa Anita Historical Society

1985 The San Dimas Experimental Forest and the Dalton Watershed: 50th Anniversary. Pacific Southwest Forest and Range Experiment Station: Berkeley, CA.

San Gabriel and Lower Los Angeles Rivers and Mountains Conservancy 2001 Common Ground, from the Mountains to the Sea. Available online at: [http://www.rmc.ca.gov/plans/common_ground.html].

Scott, T.A. and D.S. Cooper 1999 Summary of Avian Resources of the Puente- Chino Hills Corridor. Publisher: Location.

Sieh, Kerry E. 1984, September “Lateral Offsets and Revised Dates of Large Prehistoric Earthquakes at Pallett Creek, Southern California.” Journal of Geophysical Research, vol. 89, no. B9, pp. 7641- 7670.

Stein, Eric D., Shawna Dark, Travis Longcore, Nicholas Hall, Michael Beland, Robin Grossinger, Jason Casanova, and Martha Sutula. 2007 Historical Ecology and Landscape Change of the San Gabriel River and Floodplain. Southern California Coastal Water Research Project Technical Report #499.

Stein, Bruce A, Lynn S. Kutner, and Jonathan S. Adams editors. 2000 Precious Heritage: The Status of Biodiversity in the United States. Oxford University Press: United States.

Stephenson, John R. and Gena M. Calcarone. 1999 Southern California Mountains and Foothill Assessment. United States Department of Agriculture, Forest Service, GTR: PSW-GTR-172.

U.S. Department of Agriculture, Forest Service 2005 Southern California National Forests Plan: Land Management Plan, Angeles National Forest Strategy. R5-MB-075 Available online at: http://www.fs.fed.us/r5/scfpr/projects/lmp/

U.S. Geological Survey, Southern California Aerial Mapping Project 2007 Geologic Setting of the Transverse Range Province. Available online at http://scamp.wr.usgs.gov/scamp/html/scg_prov_trans.html (Accessed 1/2007).

Weldon, Ray, Thomas Fumal and Glenn Biasi. 2004, September “Wrightwood and the earthquake cycle: What a long recurrence record tells us about how faults work.” GSA Today, v. 14, no. 9, pp. 4-10.

Wright, Lauren A. and Bennie W. Troxel 2002 Levi Noble: Geologist: His Life and Contributions to Understanding the Geology of Death Valley, the Grand Canyon, and the San Andreas Fault. USGS Open-File Report 02-422. United States Geological Survey, United States Department of the Interior.

Wohlgemuth, Peter, United States Forest Service, San Dimas Experimental Forest 2007 Personal communication with Barbara Butler, National Park Service, Pacific West Region January 2007.

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Consultations: Paul Beier, Associate Professor of Wildlife Ecology, School of Forestry, Northern Arizona University Bill Brown, Former USFS Biologist for the Angeles National Forest (retired) Bruce Carter, Geologist, Pasadena City College (waiting more information) Robert Fisher, USGS, Biologist Naomi Fraga, Botanist, Rancho Santa Ana Botanical Garden Deanna Greco, Geologic Resources Division, NPS Orlando Mistretta, Research Associate, Rancho Santa Ana Botanical Garden Janet Nickerman, USFS, Angeles National Forest, Botanist Robert Powell, USGS, Project Chief San Gabriel Geologic Resources Leslie Welch, USFS, Angeles National Forest, District Wildlife Biologist Peter Wohlgemuth, Director, USFS, San Dimas Experimental Forest

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