California Sagebrush (Edible Plants on UC Berkeley Campus)

California Sagebrush

Artemisia californica

Description ⁴

More info for the terms: achene, adventitious, cover, litter, presence, root crown, sclerophyllous, shrub

This description provides characteristics that may be relevant to fire ecology, and is not meant for identification. Keys for identification are available (e.g., [60,94,155,156,210]).

California sagebrush is a drought-deciduous subshrub [14,21,30,52,63,93,168,210] with several to numerous stems arising from the root crown [79]. It grows to a height of 2 to 5 feet (0.5-1.5 m) and is the tallest shrub in the coastal sage scrub community [146,155,156,210]. Lower branches are woody and generally do not exceed 0.2 inch (50 mm) in diameter [129]. California sagebrush branches support numerous leaves from 0.8 to 2 inches (2-5 cm) long and 0.5 to 1 mm wide [79,155,156]. Leaves are seasonally dimorphic [203]. Leaves attached to the main branches or stems are slightly larger and appear early in the growing season. Most of the larger leaves remain on the stem during the dry season, although they may wilt [68,70,204]. On lower branches, side-shoots develop from the leaf axils of larger leaves. The side-shoots develop smaller, persistent leaves [70,72]. The smaller leaves remain wilted for long periods of time under water stress and rehydrate within hours of rainfall [204]. Due to the presence of terpenes, leaves are highly aromatic [93,209]. The inflorescence, 4 to 12 inches (10-30 cm) long and 0.4 to 4 inches (1-10 cm) broad [79], produces 20 to 50 flower heads, with each head containing 15 to 30 disk florets [79,146]. Inflorescences also produce 6 to 10 pistillate flowers [60,94]. California sagebrush flowers are normally yellowish or brownish in color, but along desert borders they are commonly red [79]. The fruit, an achene, is extremely small and lightweight (60 Âµg/seed) [15,54,79,146].

Allelopathy: The essential oil from California sagebrush contains 5 toxic terpenes. It has been suggested that the release of terpenes by California sagebrush contributes to the relative lack of vegetation under and adjacent to the shrub [82,121,213]. During the 1st rains of December, the leaf drip from California sagebrush is toxic. The rain leaches toxins from the leaves and litter that is absorbed by the soil, adding to toxins previously deposited by volatilization during the dry season [116].

Community structure and productivity: In a coastal sage scrub community in the Santa Monica Mountains, California sagebrush and black sage comprise approximately 75% of the community cover. The mean annual aboveground live biomass, mean annual aboveground primary production, and litterfall of the coastal sage scrub community are 925 g/mÂ², 355 g/mÂ², and 199 g/mÂ², respectively [68]. Similar research in the Santa Monica Mountains assessed the biomass and production of California sagebrush in stands burned 22 years prior to the measurements. California sagebrush peak aboveground biomass (June) and net annual production are presented in the following table [72]: Foliage Wood Dead Twigs Inflorescences Twigs Total Peak aboveground biomass (g/mÂ²) 51.4 377.4 101.4 ----* ---- 530.2 Net annual production (g/mÂ²/yr) 31.3 ---- ---- 3.1 20.6 55.0 *No data

Photosynthesis/transpiration: California sagebrush plants have a thin leaf cuticle and numerous stomata that allow for a high photosynthetic rate in response to water availability. Consequently, California sagebrush has a higher transpiration rate and a longer period of water stress than sclerophyllous species with thick leaves and deep roots [57,139,146].

Roots: California sagebrush plants have fragile, fibrous roots that penetrate shallowly into the soil [9,30,92,139,146,163]. The shallow root system allows for rapid soil moisture absorption and growth at the beginning of the rainy season [56,139,146].

Adventitious rooting was observed within California sagebrush communities at Starr Ranch, Orange County. The development of adventitious roots occurred at the basal portions of their stems, an area covered with soil from erosion or silt deposits. In areas of packed soil, adventitious roots did not occur in California sagebrush. Of 98 California sagebrush plants sampled, approximately 10% exhibited adventitious roots [122].

Distribution ⁵

More info for the term: association

California sagebrush is endemic to California [60,107,155,156] and Baja California [118,204,210]. The distribution of California sagebrush is categorized within 4 major floristic associations. The floristic associations and their ranges are as follows: 1) Diablan: found from San Francisco region south to northern Santa Barbara County; 2) Venturan: a coastal group found from northern Santa Barbara County south through coastal Los Angeles County; 3) Riversidian: a cismontane inland group found from inland Los Angeles County, western Riverside County, and inland San Diego County; and 4) Diegan: a Baja-influenced group found from Orange County and coastal San Diego County south into northwestern Baja California [13,204]. California sagebrush distribution and occurrence is greatest in the Riversidian floristic association [202]. California sagebrush also occurs on some of the Channel Islands (Santa Clemente, Santa Catalina, Santa Cruz, San Miguel, San Nicholas, and Santa Rosa ) [146,155,169,205]. In Baja California, California sagebrush extends 200 miles (325 km) south of the Mexican border to approximately El Rosario [5,51,118,204]. Plants Database provides a distributional map of California sagebrush.

Habitat characteristics ⁶

More info for the terms: allelopathy, cover, frequency, litter, presence, shrub, shrubs

California sagebrush is primarily associated with coastal sage scrub sites, but has limited occurrence in chaparral communities. It is best developed on the coastal side of mountains below chaparral [85,88].

Air pollution: California sagebrush is sensitive to sulphur dioxide pollution. A significant (p<0.01) decrease in California sagebrush foliar cover occurred in shrubs located from 1,600 to 4,900 feet (500-1,500 m) downwind from an oil refinery's sulphur dioxide stacks near Santa Maria, California. Annual sulphur dioxide concentrations (25-year period) emitted from the oil refinery range from 0.09 to 0.17 ppm [171]. Further studies have been conducted on the response of California sagebrush to air pollution in the Santa Monica Mountains near Los Angeles. Where above-average levels of sulphur dioxide and ozone persist, visible foliar damage (fasciated stems) was present [206].

Aspect: California sagebrush plants located on north-facing sites of coastal sage scrub in southeastern Orange County are significantly (p<0.001) taller and have significantly (p<0.002) greater aerial cover/shrub/mÂ² than plants on south-facing sites [54]. Aspect Height (mÂ±sx) Aerial cover/shrub/mÂ±sx North 1.34Â±0.04 1.04Â±0.10 South 1.11Â±0.05 0.59Â±0.09

At 120 sites in southern California, the frequency (%) of California sagebrush on 2 aspects and 3 slopes was measured. The averages are presented in the table below [118]: Community type Aspect Slope North-facing South-facing 0-5Â° 6-15Â° 16Â°+ California sagebrush 9 12 8 17 8 California sagebrush-eastern Mojave buckwheat-white sage 13 16 23 17 12 California sagebrush-coyote bush-basin wildrye 9 3 8 6 6 San Luis purple sage-California sagebrush 30+ 10 8 17 22 California brittlebush-California sagebrush 0 10 0 3 8

Climate: California sagebrush primarily occurs in the mediterranean climate zone, which is characterized by hot, dry summers and mild, moist winters [62,118]. California sagebrush has a bimodal distribution in that it can occur in both the coastal plain, maritime climate and the hot interior of the coastal valleys [40,84,93]. Average yearly precipitation ranges from 10 to 18 inches (250-450 mm) [18,30,40,50,54,118,149,166,207], and approximately 90% of the precipitation falls between November and April [18,40,50,118].

In a modeling experiment, Malanson and others [131] estimate that optimal California sagebrush growth occurs when precipitation ranges from 4 to 10 inches (100-250 mm), the coldest winter temperatures range from 50 Â°F to 54 Â°F (9-12 Â°C), and the warmest summer temperatures range from 75 Â°F to 81 Â°F (24-27 Â°C). Extensive climatic data from the San Gabriel Mountains where California sagebrush is dominant can be found in the review by Miller [138].

Community zonation: Where California sagebrush encroaches into grasslands, the area surrounding California sagebrush generally looks bare. The bare zone, often 3 to 6 feet (1-2 m) wide, has been attributed to allelopathy, animal influences, and soil moisture [16,57,98,116,116,118,150,153,154,173,209].

Though appearing bare in comparison to the grassland and shrub communities, the bare zone is actually comprised of short herbs approximately 1 inch (3 cm) tall. Bare-looking zones generally occur around large, dense shrub assemblages, not where individual or scattered shrubs occur [80,81,116].

At 2 sites, 1 near La Purisima Mission, the other at the base of the Santa Ynez Mountains, Halligan [80] researched possible causes of bare zones surrounding California sagebrush stands. To test the hypothesis that herbivory and granivory causes bare zones between grasslands and shrub zones, the researcher fenced in a 3,400 ftÂ² (320 mÂ²) area encompassing grassland, the bare zone, and shrubland. Following 1 year of protection, the grassland had invaded 20 inches (40 cm) into the border zone. During the same period in an unprotected area, the grassland regressed from the shrub stand, leaving the border zone 30 inches (70 cm) wider. Within the new border zone, an abundance of brush rabbit feces was present and short animal trails were noticeable, suggesting that small mammals play a part in the creation of bare zones. The research further concluded that California sagebrush allelopathy was a minor contributor to the creation of bare zones. The growth of 2 common herbs, coast tarweed (Madia sativa) and smooth catsear (Hypochaeris glabra), planted under California sagebrush and exposed to the shrub's volatiles, was significantly inhibited (p<0.05). However, 2 common grass species (ripgut brome (Bromus diandrus ssp. rigidus) and rattail fescue (Vulpia myuros)) were not significantly affected by California sagebrush allelopathy. Halligan also found that soil moisture, rainfall, and throughfall of precipitation in the shrub zone are more variable than in grasslands, which also plays a minor part in the presence of bare zones. Further research is available on bare areas associated with California sagebrush [81,83].

Elevation: California sagebrush occurs from 0 to 3,000 feet (0-800 m) but is most common from 500 to 1,500 feet (200-460 m) [85,88,94,155,156]. Its presence is scattered and isolated above 1,500 feet (460 m), where it generally occurs in chaparral belts on shallow soils [85,88,114].

The percent frequency of California sagebrush-dominated communities at different elevations was measured at 120 sites in southern California. The findings are presented in the table below [118]:

Elevation (% frequency)

Community type 0-500 feet 500-1,000 feet 1,000-1,500 feet 1,500-2,000 feet 2000+ feet Monotypic 0 0 13 19 23 California sagebrush-eastern Mojave buckwheat-white sage 0 18 16 23 23 California sagebrush-coyote bush-basin wildrye 7 12 6 0 8 San Luis purple sage-California sagebrush 25 47 16 0 23 California brittlebush-California sagebrush 21 0 0 3 0

Floodplains: California sagebrush may appear in riparian and floodzones [90,115,181]. Due to the lack of perennial water, several floodplain systems in southern California are composed of unique scrub vegetation rather than the more common riparian woodlands. Of the 10 major floodplain scrub communities, California sagebrush occurs in 4 (San Sevaine, Cucamonga, San Antonio, and San Gabriel). Floodplain scrub vegetation is periodically subjected to severe flooding, erosion, nutrient-poor substrates, and the presence of subsurface moisture. Floodplain scrub communities are found exclusively on the coastal side of major mountain ranges in southern California [90].

Litter: California sagebrush tends to occupy and dominate in sites with a "low" litter mass [202].

Soil: California sagebrush occurs on virtually all soil types, excluding serpentine [42,146]. It has no strong soil type preference, making it the most common species in coastal sage scrub communities [57]. It is the only dominant plant in coastal sage scrub communities that does not exhibit a significant (p<0.01) substrate preference [202]. Soil/substrate types associated with California sagebrush include loam to clayey loams [15,78], sandy loams, and loamy sands. The soils often containing large amounts of gravel, are typically thin and undeveloped, and have little ability to retain nutrients and water [1]. Extensive soil data from a California sagebrush community on Banner Ridge, San Diego County, are presented in a review by Bradbury [29] and from boundary areas between annual grasslands and coastal sage scrub in the review by Hobbs [98].

Transpiration and photosynthesis: In coastal sage scrub communities of the Santa Monica Mountains, California sagebrush has the lowest maximum rate of transpiration and photosynthesis of the dominant plants. The maximum transpiration (g H2O/dmÂ²/hr) and photosynthesis (mg CO2/dmÂ²/hr) rates for California sagebrush in 1968 were 0.67 and 4.02, respectively [93].

Edible ⁷

This plant has many herbal uses especially in terms of respiratory ailments. Some Native Americans used it for teeth problems while others used it with wild tobacco for smoking. Because of its strong scent, it also worked well as an insect repellent.