Big Ridge

Big Ridge is a 9,087-acre Inventoried Roadless Area within the Kaibab National Forest's North Kaibab Ranger District, occupying plateau terrain in Coconino County, Arizona. The principal landforms are Big Ridge itself — a broad benchland of the North Kaibab Plateau — and Trail Canyon, a drainage incised into the plateau's edge. Pasture Canyon headwaters, the Big Ridge Apron, and Buffalo Trick Tank form the primary water features; the plateau's relatively flat topography means surface water collects in tanks and seasonal catchments rather than perennial streams.

The area spans one of the most complete elevational sequences on the Kaibab Plateau. At lower elevations, Colorado Plateau Pinyon-Juniper Woodland forms the matrix, dominated by Two-needle Pinyon Pine (Pinus edulis) and Utah Juniper (Juniperus osteosperma), with Rocky Mountain Juniper (Juniperus scopulorum) appearing on rockier sites. Above, Southern Rockies Ponderosa Pine Woodland features Southwestern Ponderosa Pine (Pinus brachyptera) in open savanna structure; Fendler's Whitethorn (Ceanothus fendleri), Apache-plume (Fallugia paradoxa), and Mountain Snowberry (Symphoricarpos rotundifolius) occupy the shrub layer. Southern Rockies Mixed Conifer Forest and Rocky Mountain Spruce-Fir Forest mantle the upper slopes, and Rocky Mountain Aspen Forest and Subalpine Meadow occupy moist draws and cool benchlands at the highest elevations. Showy Green-gentian (Frasera speciosa) and Scarlet Skyrocket (Ipomopsis aggregata) bloom in forest openings.

Two notable endemic cacti with IUCN conservation status occur on this plateau. Kaibab Pincushion Cactus (Pediocactus paradinei), rated Endangered by the IUCN and endemic to the Kaibab Plateau, grows in specific rocky openings in the pinyon-juniper zone — one of the few places in the world where this species occurs. Siler's Fishhook Cactus (Sclerocactus sileri), rated Vulnerable by the IUCN, occupies alkaline soils and open rocky habitat at the plateau's lower margins. Wheeler's Thistle (Cirsium wheeleri, IUCN Vulnerable) blooms in forest openings and meadow margins. Pinyon Jay (Gymnorhinus cyanocephalus, IUCN Vulnerable) works in noisy flocks across the pinyon woodland, caching seeds that regenerate the woodland structure. Flammulated Owl (Psiloscops flammeolus) nests in old ponderosa snags and hunts insects on summer nights; Abert's Squirrel (Sciurus aberti) feeds on ponderosa seed cones in the mid-elevation forests; and Clark's Nutcracker (Nucifraga columbiana) makes long foraging flights between the upper spruce-fir stands and the pinyon-juniper belt below. Mule Deer (Odocoileus hemionus), Wapiti (Cervus canadensis), and Pronghorn (Antilocapra americana) use the plateau's open grasslands and shrub zones. Portions of this area fall within the potential range of several federally listed species; see the Conservation section for details.

The Arizona Trail and Great Western Trail both cross the Big Ridge area, providing the primary access routes across the plateau. A traverse of the area follows the plateau surface from the pinyon-juniper woodland at the plateau's edge, ascending through ponderosa pine and entering the mixed conifer forest where Douglas-fir and white fir shade the trail. Trail Canyon cuts into the plateau's rim country at the north end, offering views across the Kaibab's northern cliffs toward the Utah border.

The lands comprising the Big Ridge roadless area occupy the North Kaibab Plateau, one of the most isolated table-top landscapes in the American Southwest. The name "Kaibab" derives from the Southern Paiute term meaning "mountain lying down" — a description of the plateau's flat summit as seen from the surrounding desert below [1]. Archaeological evidence indicates that the Cohonina people occupied the plateau and its canyon margins from approximately 700 to 1100 CE, constructing masonry dwellings and pit-house structures along the rim country [2]. The Cohonina left behind ceramic vessels and related artifacts now documented across many sites on the Kaibab. After their departure around 1100 CE, Southern Paiute peoples traveled the rim country seasonally for hunting and ceremonial purposes, and Navajo use of the plateau's north-rim canyon system is also documented.

Euro-American contact arrived in the latter half of the 19th century as cattle and sheep operations established themselves on the plateau's benchlands. Livestock grazing on the open ponderosa pine and mixed conifer country expanded through the 1880s and 1890s; the plateau's high-elevation grasslands and spruce-fir zones drew sheep operations in particular, with summer grazing extending across the subalpine meadows of the upper Big Ridge terrain. Logging interests also targeted the plateau's large-diameter ponderosa pine, though the North Kaibab's remoteness — the Grand Canyon blocking access from the south, the Utah desert limiting it from the north — constrained commercial timber extraction compared to more accessible forests. The stock tanks that dot the plateau benchlands, including those at the Big Ridge Apron and Buffalo Trick Tank, date in many cases to early-20th-century range management operations.

Federal protection came in stages. On September 10, 1893, President Grover Cleveland proclaimed the Grand Canyon Forest Reserve, bringing the Kaibab Plateau under federal protection as one of the earliest forest reserves in the Southwest [2]. In 1906, following the steep decline of the area's deer population due to predator-killing campaigns, the federal government designated the North Kaibab as a Federal Game Preserve — the only national forest in the United States to hold that distinction [1]. On July 2, 1908, the reserve was formally reorganized as the Kaibab National Forest [1]. The game preserve program's removal of mountain lions and wolves had an unintended consequence: by the early 1920s, the North Kaibab deer herd had expanded far beyond carrying capacity and then collapsed in a mass die-off — a cycle that became a foundational case study in American wildlife population science.

Today, Big Ridge lies within the North Kaibab Ranger District of the Kaibab National Forest, its 9,087 acres draining into the Pasture Canyon headwaters and protected under the 2001 Roadless Area Conservation Rule.

Vital Resources Protected

Kaibab Pincushion Cactus and Soil-Sensitive Plant Communities

Big Ridge's roadless condition preserves the rocky, open pinyon-juniper microhabitats on which Kaibab Pincushion Cactus (Pediocactus paradinei, IUCN Endangered) depends. This small cactus is endemic to the Kaibab Plateau — it occurs nowhere else in the world — and its populations are restricted to specific undisturbed soil openings in Colorado Plateau Pinyon-Juniper Woodland (21.7% of area) and Colorado Plateau Pinyon-Juniper Shrubland (18.2% of area). Siler's Fishhook Cactus (Sclerocactus sileri, IUCN Vulnerable), rated globally as NatureServe Global Status G1 — critically imperiled — is similarly restricted to intact, low-disturbance rocky soils on this plateau. Both species are listed under federal regulations as species for which road construction and associated soil disturbance represent primary documented threats.

Pinyon-Juniper Woodland Continuity

Colorado Plateau Pinyon-Juniper Woodland and Shrubland together cover approximately 40 percent of the Big Ridge area, forming one of the largest contiguous blocks of this habitat in the North Kaibab Ranger District. The roadless condition maintains woodland interior free from the edge fragmentation, snag removal, and canopy clearing that road construction generates — conditions essential for Pinyon Jay (Gymnorhinus cyanocephalus, IUCN Vulnerable), whose colonial seed-caching behavior requires intact woodland at a spatial scale that cannot be sustained in fragmented patches. Fire regime alteration has already shifted much of this woodland type toward denser, closed canopies that reduce the rocky openings where endemic cacti persist; the absence of road corridors prevents the additional disturbance vectors that compound these changes.

Mixed Conifer Critical Habitat for Mexican Spotted Owl

Southern Rockies Mixed Conifer Forest on Big Ridge's upper elevation benchlands is designated as critical habitat for Mexican Spotted Owl (Strix occidentalis lucida, Threatened). This forest type requires large-diameter old-growth trees, structural complexity including snags and downed wood, and the interior conditions that develop only in stands free from logging or road-clearing disturbance. The roadless condition preserves these old-growth structural elements across the area's mixed conifer zone, maintaining the multi-layered canopy and quiet interior that Mexican Spotted Owl requires for nesting and foraging through the breeding season.

Potential Effects of Road Construction

Soil Disturbance and Endemic Cactus Habitat Loss

Road construction in the Big Ridge area would directly destroy the microhabitat on which Kaibab Pincushion Cactus and Siler's Fishhook Cactus depend. Both species occur in the specific rocky, stable-soil openings that road grading, cut slopes, and fill operations permanently eliminate. Because these plants are restricted to a single plateau, any population lost to construction disturbance cannot be offset by immigration from other areas — the global range of Kaibab Pincushion Cactus is entirely within and adjacent to the Kaibab National Forest, and road construction represents an unrecoverable loss of globally rare habitat.

Invasive Annual Grass Establishment and Fire Regime Alteration

Road construction across Big Ridge's Pinyon-Juniper Woodland and Rocky Mountain Gambel Oak Shrubland (14.6% of area) creates disturbed mineral soils that allow cheatgrass (Bromus tectorum) to colonize along road margins and drainage corridors. In both the pinyon-juniper and Gambel oak types, cheatgrass produces continuous fine fuel loads that elevate fire frequency well above the adaptive thresholds of these woodland species. Catastrophic fire in the pinyon-juniper zone eliminates the mature seed-bearing trees that Pinyon Jay requires and destroys the specific rocky micro-openings where endemic cacti grow; recovery of both the woodland structure and the cactus populations requires decades, and some disturbance profiles result in permanent type conversion to annual grassland.

Fragmentation of Mixed Conifer Critical Habitat

Road construction through the Mixed Conifer Forest would break the canopy continuity required by Mexican Spotted Owl, introducing road clearings that expose interior forest to edge effects — elevated wind, temperature, and solar radiation — that degrade old-growth structure in the adjacent intact stands. Linear clearings also facilitate human access and disturbance of owl nesting sites during the breeding season, a documented stressor for a species sensitive to nest disturbance. Once old-growth structural complexity is reduced by logging for road clearings, recovery of the multi-layered canopy and large-diameter snag component takes more than a century even under active management.

Big Ridge is a 9,087-acre roadless area on the North Kaibab Plateau within the Kaibab National Forest's North Kaibab Ranger District, Coconino County, Arizona. The Arizona Trail (Trail No. 101) and the Great Western Trail (Trail No. 150) both cross the area, providing the two primary access routes. There are no designated campgrounds within the roadless area, but the trail system provides dispersed access to the plateau's benchlands, forest, and canyon rim country.

The Arizona Trail enters the Big Ridge area as part of its 800-mile route from Mexico to Utah, crossing mixed conifer forest and ponderosa pine woodland across the plateau's upper elevations before descending toward the North Kaibab's canyon rim country. In this section, the trail passes through the full elevational sequence from pinyon-juniper at the lower margins through ponderosa pine savanna, mixed conifer forest, and Rocky Mountain Aspen stands in the moist draws. The Great Western Trail — a 4,500-mile corridor from Mexico to Canada — parallels portions of the Arizona Trail on the North Kaibab, designed for horseback and mountain bike use. Both trails use native surface material.

Wildlife observation is a major activity in the Big Ridge area. Mule Deer (Odocoileus hemionus) are abundant throughout the pinyon-juniper and ponderosa zones, particularly at dawn and dusk. Wapiti (Cervus canadensis) use the mixed conifer and aspen benchlands, and Pronghorn (Antilocapra americana) occupy the open grassland and shrub-steppe on the plateau's lower flats. Abert's Squirrel (Sciurus aberti), the North Kaibab's most visible small mammal, forages in the ponderosa zone. Clark's Nutcracker (Nucifraga columbiana) and Pinyon Jay (Gymnorhinus cyanocephalus) — the IUCN Vulnerable corvid endemic to western pinyon woodland — are the characteristic birds of the two dominant tree communities respectively. Flammulated Owl (Psiloscops flammeolus) calls from old-growth ponderosa snags on warm summer evenings; Grace's Warbler (Setophaga graciae) forages in the ponderosa canopy; and Virginia's Warbler (Leiothlypis virginiae) nests in dense shrub at the lower elevation transitions.

For those seeking the Kaibab Pincushion Cactus (Pediocactus paradinei) — an IUCN Endangered species found only on the Kaibab Plateau — Big Ridge's pinyon-juniper zone is within the cactus's range. The species grows in specific rocky openings and its late-spring bloom is a destination for botanists and photographers. Siler's Fishhook Cactus (Sclerocactus sileri, IUCN Vulnerable) also occurs at lower elevations.

For birding, Jacob Lake Campground (117 species, 179 checklists) and Jacob Lake Inn (100 species, 424 checklists) are the nearest established eBird hotspots and serve as the primary staging point for North Kaibab Plateau birding. Kaibab NF — Kaibab Plateau (131 species, 109 checklists) captures the plateau's open-country species, including Pinyon Jay, Clark's Nutcracker, Cassin's Finch, and Evening Grosbeak. The Vermilion Cliffs — Condor Viewing Site (127 species, 952 checklists) lies 24 kilometers to the north, offering regular California Condor sightings. Jacob Lake serves as the primary access point for lodging and services on the North Kaibab.

The qualities that make Big Ridge valuable for hiking, wildlife observation, and botanical trips all depend on the roadless condition. The Kaibab Pincushion Cactus occupies microhabitats that require stable, undisturbed soil; the Pinyon Jay colonial movements and Flammulated Owl nesting sites depend on intact woodland with minimal human intrusion; and the trail experience on both the Arizona Trail and Great Western Trail draws its character from the undisturbed plateau forest, open views, and quiet that a roadless landscape provides. Vehicle traffic, road margins, and the associated edge disturbance would degrade each of these conditions.