Quercus kelloggii Newb. California Black Oak Fagaceae Beech family Pliiiip M. McDonald California black oak (Quercus kelloggii) exceeds all Climate other California oaks in volume, distnbution, and altitudinal range. Yet this deciduous hardwood has Hot dry summers and cool moist winters charac.­ had little sustained commercial use and almost no terize the climate where California black oak grows. management, even though its wood closely resembles Within the species' natural range, average annual that of its valuable, managed, and heavily used precipitation varies widely. In the valleys of south­ counterpart-northern red oak (Quercus rubra)-in western Oregon, it exceeds 760 mm (30 in); in the Eastern United States. northwestern California, it ranges from 760 to 2540 First collected in 1846 near Sonoma, CA, the mm (30 to 100 in); and in northeastern California, species was not named until 1857 when John New­ only 300 to 380 mm (12 to 15 in) of rainfall annually. berry called it kelloggii in honor of Albert Kellogg, a Throughout the range of black oak in north-central pioneer California botanist and physician (17). In and central California, annual precipitation averages later botanical works, the species was called Q. 1010 to 1780 mm (40 to 70 in) but may exceed 2920 californica and black oak or Kellogg's oak. mm (115 in) locally. In these areas less than 4 per­ Acorns of California black oak were carried from cent of the yearly precipitation falls from June San Francisco to England in 1878. Thirty-two years through September. In tbe mountains of southern later, trees from these acorns were described as being California, precipitation averages 910 mm (36 in). 30 feet tall and making good growth (10). Black oak achieves its best size and abundance in areas where snowfall accounts for 10 to 50 percent Habitat of the y~ar's precipitation. Average mean daily temperatures range from -1° to 8° C (31° to 46° F) during January, and from 19° Native Range to 28° C (66° to 82° FJ in July. The last killing spring The north-south range of California black oak (fig. frost is expected between March 15 and June 9, and 1) is about 1255 km (780 mi). In Oregon, its natural the first killing frost in the fall between August 30 range extends from just north of Eugene, southward and November 30. Periods free of killing frosts range through the valleys west of tbe Cascade Range. The from 82 to 270 days. Throughout an 18-year period, species is especially frequent along lower slopes in the highest temperature recorded at 1125 m (3, 700 fairly dry sections of the Klamath and Cascade ft) elevation in the center of black oak's zone of Mountains but never grows near the Pacific Ocean. greatest size and abundance was 39° C (103° FJ; the In California, black oak is found in the northern minimum temperature was -15° C (5° Fl. The max­ Coast Range from the Oregon State line to Marin imum number of frost-free days was 215 and the County and tben intermittently in the Santa Cruz minimum was 116 (35). and Santa Lucia Mountains. This oak becomes more common on the San Bernardino, San Jacinto, and Soils and Topography Agua Tibia Mountains, extending to just south of Mt. Laguna, and is now recognized as being in Baja Probably the most important single soil variable California (5). In California's Sierra Nevada, the that· limits the presence of California black oak is species grows abundantly along the west side, from internal drainage. Black oak is not found growing near Lassen Peak to near Kings Canyon. California "with its feet wet." The species is adapted to soils black oak becomes intermittent southward to the derived from diverse parent materials-andesite, Tehachapi Mountains, where it again increases in basalt, granite, pumice, quartz diorite, sandstone, abundance. California black oak is generally confined schist, shale, and volcanic tuffs and breccias. Califor· · to the westside, but a few stands have been found nia black oak only rarely is found on soils originating along the eastside of the Sierra Nevada. The species from serpentine. Occasionally it grows on soils approaches the Nevada State line northeast of derived from ultrabasic parent material, but mostly Beckwourth Pass but is not reported in Nevada. where above-average amounts of calcium seem to offset the deleterious effects of magnesium. Soil textures favoring this oak range from medium­ The author is Principal Silviculturist, Pacific Southwest Forest textured loams and clay-loams to the more coarse­ and Range Experiment Station, Berkeley, CA. textured gravelly-clay-loams and sandy-loams. In- Reprinted from: . Bums, Russell M.; Honkala, Barbara H., tech. coords. 1990. Sllvics of North America. Volume 2, Hardwoods. AiricUlture Handbook 654. 661 Washington, DC: U.S. Department of Agriculture; 877 p. Quercus kelloggii soo creasing clay content in the surface soil usually means a decreasing incidence of black oak. In fact, this species rarely is found on soils with clay topsoils, particularly ifthe clay is heavy and sticky. Black oak usually grows on thin soils and rocky slopes, but always at the cost of abundance or form, or both. In general, 'black oak grows best on medium- to coarse­ textured, deep, and well-drained soils. About 75 soil series in California have been iden­ tified by the California Cooperative Soil-Vegetation Survey and the National Cooperative Soil Survey as supporting California black oak. Important soil series in the California Coast Range include Boomer, Cohasset, Josephine, Sites, and Sheridan. In the Sierra Nevada, Aiken, Chawanakee, .Holland, Stump Springs, Corbett, and Tish Tang support abundant black oak. Soils in the southern Cascade and Klamath Mountains that often are clothed with black oak include Aiken, Cohasset, McCarthy, Sites, Tournquist, Behemotosh, Horseshoe, and Neuns. Fourteen soil series have been identified in Oregon, mostly on series similar to those in California. Most of the soils in both States are found at higher eleva­ tions and support forest vegetation rather than oak woodland or chaparral. Soil orders are mostly Al­ fisols and Inceptisols, occasionally Mollisols. The best black oak stands in the Coast Range and Klamath Mountains are found on deep, slightly acid loams and gravelly-clay-loams derived from sandstone and shale. In the southern Cascade Range and northern Sierra Nevada, black oak grows best on deep loams and clay-loams originating from metavolcanic rocks. In the central and southern Sier­ ra Nevada and in the Transverse and Peninsular Ranges, this oak grows well on deep, acid to moderately acid sandy-loam soils derived from granitic rock. California black oak grows within a wide elevation­ al range-from the level gravelly floors oflow valleys to alluvial slopes, rocky ridges, and high plateaus. Most of the terrain is rugged, steep, and dissected by major streams and ephemeral drainages. In Oregon, the elevational range of black oak varies from 137 m (450 ft) near Eugene, to more than 305 m (1,000 ft) on the low rounded hills in the Umpqua River drainage (13). The oak also is found within this elevational range on the eastern slopes of the Coast Range and the western slopes of the Cas­ 1984 cades. In south central Oregon and the Klamath 0 •00 200 Mountains,' black oak grows at higher elevations of 610 to 915 m (2,000 to 3,000 ft). 0 !00 200 300 400 500 In California's Coast Range, black oak is found from about 152 m (500 ft) along the Mattole River in Humboldt County to 1830 rn (6,000 ft) in the Yolla Figure I-Native range ofCalifornia black oak. Bolly Mountains. Black oak reaches its lowest eleva­ 662 Quercus kelloggii tion (60 m or 200 ft) in the Napa and Santa Rosa resented a degree of mesophytism between that of Valleys. Most black oak in the central portion of the the chaparral and the conifer forest (7). The species Coast Range grows between 305 to 1525 m (1,000 to was also thought to be more a persistent subclimax 5,000 ft), gradually increasing in elevation but nar­ than climax. rowing in range to 1220 to 1982 m (4,000 to 6,500 ft) California black oak, or its fossilized equivalent in Santa Barbara and eastern Ventura Counties. (Quercus pseudolyrata), was much more widespread Farther south in the Transverse Range the species is in past ages than now. Fossil remains indicate that found at elevations of 1403 to 2135 m (4,600 to 7,000 the species was abundant in sedimentary deposits ft) (39). In the San Jacinto Mountains, black oak near Spokane and Ellensburg, WA, in the John Day reaches 2440 m (8,000 ft) and, at its southernmost Valley and Blue Mountains of Oregon, and in extension in the Peninsular Range of San Diego northwestern Nevada (6). These deposits- date back County, it grows within the 1525- to 1830-m (5,000­ to the Miocene epoch of 12 to 26 million years ago. to 6,000-ft) elevation. Increasing aridity is the probable cause for the The elevational range of black oak in California's smaller natural range of black oak today. Cascade Range is from about 183 m (600 ft) in The most common botanical associate of black oak western Shasta County to 1906 m (6,250 ft) in south­ is ponderosa pine (Pinus ponderosa var. ponderosa). central Shasta County. In the Sierra Nevada, lower The two species intermingle over vast acreages, ex­ elevational limits for black oak range from 458 m cept that black oak is found at lower elevations, on ( 1,500 ft) in the north to 1220 m (4,000 ft) in tbe sites too poor to support pine, and in certain areas south.