Oak Glen Preserve

Oak Glen Preserve is a nature preserve owned and managed by The Wildlands Conservancy, a nonprofit land conservancy. Covering 909 acres (3.68 km²) in San Bernardino County, California, it is located in the western foothills of the San Bernardino Mountains. The preserve includes the Southern California Montane Botanic Garden and Children's Outdoor Discovery Center, as well as Los Rios Rancho, a historic apple orchard. It receives about 600,000 visitors annually. More preserves can be found in the list of preserves.

The preserve consists of several discrete parcels. The main parcel lies in a glen around 5,024 feet (1,531 m), with its lowest point at about 4,430 feet (1,350 m). Additional parcels extend onto nearby summits, including Wilshire Peak (8,683 feet (2,647 m)) and Pisgah Peak (5,496 feet (1,675 m)).^[2][3] In 2018, The Wildlands Conservancy separated the 1,280-acre Galena Peak tract, including its 9,324 feet (2,842 m) summit, into the distinct Galena Peak Wilderness Reserve.^[4]

The preserve is located in a glen at 5,024 feet (1,531 m), beneath Wilshire Peak (8,700 feet (2,700 m)). It also includes land on surrounding summits, such as Wilshire Peak, Cedar Mountain, and Oak Glen Peak, which provide scenic backdrops for the preserve.^[5]

The preserve lies within the San Bernardino Mountains, part of the Transverse Ranges, which harbor exceptional biodiversity. Roughly 1,600 species of plants and trees occur in these mountains, about one-quarter of all botanical species found in California.^[6]

The preserve contains the Champion Oak, a canyon live oak recognized as the largest of its species and the largest oak in North America. It was measured at 473 inches (39 ft) in circumference, 124 feet in height, and a crown spread of 98 feet, earning 622 points in the American Forests Champion Tree register.^[7][8][9] The tree is estimated to be 800–1,000 years old and has been described as a “national treasure”.^[10]

Apple orchards have been part of Oak Glen since the 1860s. The community developed as a center of Southern California apple growing, its cool mountain setting contrasting with the surrounding desert.^[11]

By the late 20th century, Oak Glen’s growers faced economic pressures as global apple prices fell and visitor habits changed. Local families increasingly turned to agritourism, offering pick-your-own orchards, cider pressing, and historical reenactments to attract visitors. Los Rios Rancho was at risk of subdivision in the mid-1990s, but in 1996 The Wildlands Conservancy acquired about 3,000 acres, including the ranch and separate parcels on nearby ridgelines reaching elevations of 9,300 feet, securing both the working orchard and surrounding open space.^[12] The organization maintained Los Rios as an operating orchard and promoted organic methods while preserving the broader landscape.

Since 2004, most of the orchard has been leased to Riley Family Enterprises, which manages apple growing and associated visitor activities.

In 2014, the Southern California Montane Botanic Garden and Children's Outdoor Discovery Center were opened;^[13] the botanic garden opened with about five miles of trails, a rustic lodge used as classrooms, and a stand of giant sequoias planted a century earlier by Isaac Ford.^[6]

In 2018, pests killed many of the oak trees. The diseased trees had to be removed.^[14][15]

In December 2019, a catastrophic snowstorm devastated trees. Several feet of wet snow caused limbs to fall and hundreds of trees to topple. The damage was compounded because the trees had not shed their leaves. Thirty percent of black oaks and many sycamores were lost.^[16][17] A second snow storm hit in January 2020 causing additional damage. The damage was less severe than the prior storm because the deciduous trees had lost their leaves.^[18]

In 2020, three fires impacted the preserve. The Apple Fire burned to Wilshire Peak and threatened the Champion Oak. A 30-person inmate firefighting crew led by preserve botanist Tim Krantz cleared brush around the tree in steep terrain, protecting it from the flames.^[10] The El Dorado Fire burned the north side of Oak Glen Preserve. A third fire destroyed the Los Rios Rancho buildings (bakery, store, packing house) and the preserve's ranger shop.^[19][20][21] A couple of years later, a mudslide devastated a local business just down the road from the preserve.^[22]

Oak Glen Preserve has faced repeated ecological challenges, including invasive pests, storms, and wildfire. In 2018, infestations of the goldspotted oak borer caused widespread mortality of black oaks, requiring removal of diseased trees.^[23][24] The preserve also lost large numbers of trees during severe snowstorms in 2019–2020, and was impacted by the Apple Fire and El Dorado Fire in 2020.^[25][26]

In 2024, The Wildlands Conservancy and the Global Conservation Consortium for Oak established the Experimental Oak Woodland within the botanic garden.^[27][28][29] The project planted three types of oaks, including Engelmann oak, a species native to warmer and drier areas of Southern California. The effort is intended to build resilience to the goldspotted oak borer and anticipated climate shifts, while providing a research and education site for long-term conservation.

Oak Glen Preserve contributes to regional landscape connectivity in the Sand to Snow region. It lies within a wildlife linkage identified in the South Coast Missing Linkages plan, which emphasized the importance of maintaining habitat corridors between desert and montane ecosystems.^[30] The preserve was also included in subsequent regional planning efforts, such as the Greater I-10 Conservation Workshop, which highlighted habitat connectivity across the I-10 corridor.^[31]

Activities include picnicking, hiking, and educational programs. The northern part of the preserve includes Galena Peak (9,324 feet), Wilshire Peak (8,700 feet), Birch Mountain (7,826 feet), and additional nearby peaks such as Cedar Mountain and Oak Glen Peak, which offer scenic views.^[5]

Los Rios Rancho is Southern California's largest apple orchard and has been in operation since 1906. From September to November, visitors can pick apples and buy various apple-based products, like cider and pie. The orchard is managed through a long-term lease by Riley Family Enterprises, which operates the orchards, packing shed, and bakery, and organizes events during apple season.^[5] Each fall, Oak Glen draws large crowds for seasonal festivals such as the Apple Butter Festival, which, along with apple picking and other orchard events, makes the community a major regional tourist destination.^[32]

The preserve includes a two-mile Main Loop Trail with shaded paths and interpretive signage that highlight ponds, deciduous forest, and groves of conifers such as giant sequoias, coast redwoods, Jeffrey pines, and sugar pines.^[33] A more strenuous option is the three-mile Preservation Point Trail, which climbs steeply to a dramatic overlook.^[33]

The 220-acre Southern California Montane Botanic Garden represents a wide range of montane habitats, including ponds, streams, wetlands, oak and pine forests, chaparral, and willow woodlands.^[5][6] The garden contains a grove of about ten giant sequoias planted 50–130 years ago by local ranchers, along with some 300 additional sequoias planted by The Wildlands Conservancy in 2003.^[34] Several of the sequoias were planted by early settler Isaac Ford, who also co-founded the city of Redlands.^[6] Its themed venues have been expanded over time and are used for education and public events.^[5] Admission is free, and at its launch the Conservancy aimed to attract about 50,000 children each year.^[6]

Since opening, the Botanic Garden has hosted tens of thousands of students on free field trips that highlight Southern California’s biodiversity.^[5] The Conservancy emphasizes the garden as an accessible, family-friendly introduction to the region’s ecosystems.

The Conservancy also operates the Children’s Outdoor Discovery Center, an interactive program where a naturalist guides students in exploring local ecosystems.^[5] The Outdoor Discovery Program reaches about 22,000 students annually, and by 2024 had introduced nearly half a million students to natural settings beyond their neighborhoods.^[5] Activities include quizzes along garden trails and other hands-on experiences. The program requires reservations and is frequently used by schools across the Inland Empire.^[5]

The Southern California Montane Botanic Garden includes a series of themed venues. Notable examples are Hummingbird Hill, established in 2015 with thirty native species selected to attract hummingbirds,^[35] the Artist’s Palette garden, opened in 2016 with wildflowers chosen to evoke the colors of Monet’s paintings,^[36] and the Experimental Oak Woodland, launched in 2024 as part of a project to test oak species resistant to the goldspotted oak borer.^[37][38] Other venues include Pioneer Pasture, Stream Trail, Sacred Springs, Chaparral Vistas, the Wetlands Boardwalk, Conifers of California, Deciduous Forest, Aquatic Ecosystems, and Falling Waters.^[6] The Children’s Forest, located near the lower parking area, was established in 2003 with the planting of sequoias, cedars, and redwoods. In 2021 it was developed as a botanic garden venue with a loop trail marked by arches decorated with animal silhouettes and other interpretive features designed for children’s outdoor learning.^[39]

• List of The Wildlands Conservancy preserves

• Sanders, J.R. (2006). Oak Glen and Los Rios Rancho. Arcadia Publishing. ISBN 0-7385-4653-4.

• Oak Glen Preserve
• Oak Glen Preserve Notebook on iNaturalist
• "Pisgah Peak". Geographic Names Information System. United States Geological Survey, United States Department of the Interior.
• "Pisgah Peak, California". Peakbagger.com.
• "Wilshire Peak". Geographic Names Information System. United States Geological Survey, United States Department of the Interior.
• "Wilshire Peak, California". Peakbagger.com.