Antelope Bitterbrush Nancy L

‘Lassen’ Antelope Bitterbrush Nancy L. Shaw Stephen B. Monsen

Abstract—‘Lassen’ antelope bitterbrush is recommended for Over the last 50 years, characteristics of more than restoring depleted rangelands, burned areas, mined lands, and 200 populations of antelope bitterbrush, desert bitter- other disturbed sites in the Intermountain West. Lassen was brush (Purshia glandulosa Curran), Stansbury cliffrose, selected for its seedling vigor, upright growth habit, seed produc- and Apache-plume (Fallugia paradoxa [D.Don] Endl.) tion, productivity, and retention of overwintering leaves. Selec- have been examined in ecological studies of native stands, tion trials indicate Lassen is adapted to antelope bitterbrush range seeding studies, and species adaptation trials con- sites receiving 300 to 600 mm of precipitation at elevations rang- ducted in common garden settings in the Intermountain ing from 900 to 1,800 m. Best growth occurs on deep, coarse, region, in northern California, and in the Pacific North- well-drained, neutral to slightly acidic soils. Productive Lassen west (Davis 1983). The importance of antelope bitter- plantings have been established on such sites in northeastern brush in mule deer diets and stand depletion resulting California, eastern Oregon, and central and southern Idaho. from uncontrolled livestock grazing triggered early work with the species. More recent studies have examined species and population characteristics to provide clues to their evolutionary relationships. Use of the species in wildland Antelope bitterbrush (Purshia tridentata [Pursh] DC.) plantings has expanded to include soil stabilization, low is a widely distributed shrub of western rangelands, oc- maintenance landscaping, and community restoration. curring from British Columbia to California and eastward The collective results of this work, plus implementation from Montana to New Mexico. It grows at elevations from of seed certification systems being developed or adapted near sea level to 3,500 m on sites receiving 200 to 850 mm for wildland species by State seed certification agencies, of annual precipitation (Giunta and others 1978; Nord provide an opportunity to systematically begin (1) compil- 1965). Antelope bitterbrush, a member of the rose family, ing descriptions and performance data for commonly col- occurs as a community dominant and in other vegetation lected antelope bitterbrush populations, (2) delimiting types ranging from blackbrush (Coleogyne ramosissima the range of adaptability for individual populations, and Torr.) to big sagebrush (Artemisia tridentata Nutt.), oak (3) providing land managers and revegetation specialists brush (Quercus gambelii Nutt.), mountain brush, pinyon- with procedures for verifying seed origin. One approach juniper (Pinus L.-Juniperus L.), lodgepole pine (Pinus toward meeting these objectives is illustrated by the re- contorta Dougl. ex Loudon), and ponderosa pine (Pinus lease of ‘Lassen’, a named variety of antelope bitterbrush. ponderosa Lawson) and occasionally on exposed high- elevation ridges with limber pine (Pinus flexilis [James] Rydb.). It commonly occurs on deep, coarse-textured, well-drained, neutral to slightly acidic soils. Some stands, Lassen Release however, grow on shallow, fine-textured soils that may be Released in 1984, Lassen is a distinctive antelope bit- quite alkaline (Giunta and others 1978). terbrush ecotype that has been extensively planted and Antelope bitterbrush populations differing in site re- studied over the last 40 years. Traits of interest in reveg- quirements, seedling vigor, growth habit, and morphologi- etation work are its seed production, seedling vigor, up- cal characteristics have evolved as a result of intraspecific differentiation and recent and likely ongoing introgression right growth habit, productivity, winter leafiness, and with Stansbury cliffrose (Cowania stansburiana Torr.) palatability (Shaw and Monsen 1986; Shaw and others (Jabbes and Brunsfeld 1993; McArthur and others 1983; 1984a,b; Soil Conservation Service 1986). Lassen is rec- Stutz and Thomas 1964). A number of extensive, produc- ommended for planting in depleted rangelands, burned tive, and easily accessible populations are regularly har- areas, mined lands, and other disturbed sites within its vested by wildland seed collectors and sold to buyers area of adaptation (Monsen 1987; Monsen and Davis 1986; throughout the Intermountain, Southwest, and Pacific Shaw and Monsen 1986). Northwest regions. An understanding of the ecology and Lassen is used by big game and livestock during all sea- range of adaptability of these and other populations is sons and remains productive with moderate use. Mature, needed to aid in prescribing seed sources for planting moderately grazed plants can provide more available for- projects and to manage natural and seeded stands. age than low, spreading forms of antelope bitterbrush, particularly when snow cover is present. The large plants provide hiding and thermal cover for many vertebrates and In: Roundy, Bruce A.; McArthur, E. Durant; Haley, Jennifer S.; Mann, invertebrates. Birds, rodents, and insects consume its David K., comps. 1995. Proceedings: wildland shrub and arid land restoration symposium; 1993 October 19-21; Las Vegas, NV. Gen. Tech. Rep. INT- seeds. Lassen is an attractive shrub for low-maintenance GTR-315. Ogden, UT: U.S. Department of Agriculture, Forest Service, In- landscaping in campgrounds, recreation areas, and along termountain Research Station. roadways. The root system contributes to soil stabiliza- Nancy L. Shaw and Stephen B. Monsen are Botanists, Intermountain Research Station, Forest Service, U.S. Department of Agriculture, station, but mixed plantings with low-growing or spreading tioned at Boise, ID, and Provo, UT, respectively. species may be more effective in stabilizing surface soils.

364 Lassen’s release resulted from cooperative efforts of Nord 1963, 1965; National Oceanic and Atmospheric the U.S. Department of Agriculture, Forest Service, Inter- Administration 1982; Soil Conservation Service n.d.). mountain Research Station, Soil Conservation Service, Native Lassen stands occupy dry lake beds, alluvial fans and the Utah Division of Wildlife Resources (Shaw and or terraces, and lower foothills of the Sierra Nevada others 1984a,b). Seven State agencies in California, Idaho, Mountains. Soils are generally deep, slightly acid to neu- Nevada, and Oregon cooperated. Characteristics of the tral, gravelly to loamy sands derived from granite (Alderfer variety and performance data were made available to po- 1976; Nord 1965; Soil Conservation Service n.d.). Perme- tential users through release documents, a U.S. Depart- ability is high. Vegetation is dominated by basin big sage- ment of Agriculture, Soil Conservation Service brochure, brush (Artemisia tridentata var. tridentata), antelope and a release announcement in Rangelands (Shaw and bitterbrush, and cheatgrass (Bromus tectorum L.) with Monsen 1986; Shaw and others 1984a,b; Soil Conserva- ponderosa pine and Jeffrey pine (Pinus jeffreyi Balf. in tion Service 1986). Murray) in the foothills (Alderfer 1976; Nord 1965; Soil Conservation Service n.d.). Origin Since 1954, seed collected from this area has been planted in selection trials and field plantings in north- Lassen originates from native stands in Lassen County, eastern California (Shaw and others 1984a,b), western CA. The ecotype occurs in a narrow, 80-km strip along the Nevada (Shaw and others 1984a,b), Utah (Davis 1983), eastern base of the Sierra Nevada Mountains extending Idaho (Shaw and Monsen 1983; Shaw and others 1984a,b; from Susanville to drier sites near Doyle (fig. 1). Eleva- Welch and others 1983), and eastern Oregon (Edgerton tion at the Susanville airport is 1,250 m. Mean annual and others 1983). Results of this work indicate Lassen precipitation is 370 mm. The frost-free season averages has high potential for establishment on sites from 900 to 120 days with a range of 82 to 156 days. Average tem- 1,800 m that receive 300 to 600 mm of annual precipita- perature is 9 °C. Temperature extremes normally range tion and that support, or once supported, antelope bitter- from highs near 43 °C to lows of -9 °C, although tempera- brush. It has performed well on sites with deep, coarse, tures as low as -34 °C have been reported (Alderfer 1976; well-drained, neutral to slightly acidic soils. It does not appear well adapted to basic, fine-textured, or poorly- drained soils.

Description

Mature Lassen plants are large, leafy, upright shrubs with few basal stems, heavy lateral spur production, and long, ascending to erect leaders (Alderfer 1976) (fig. 2). McArthur (1982) found plants growing near Janesville averaged 2.2 m in height with 3 m crowns. Nord (1962) reported a large shrub found near Janesville was 4 m tall with a crown spread of 6 m and a stem circumference of nearly 1 m, measured 0.2 m aboveground. Age of the shrub was estimated at 128 years based on a count of annual growth rings.

Figure 2—Lassen antelope bitterbrush growing near Janesville, CA. Figure 1—Native Lassen stands.

365 Chromosome number for Lassen and all other antelope bitterbrush populations tested to date is 2n = 18 (Alderfer 1976; McArthur and others 1983). Alderfer’s (1976) comparisons of 20 Oregon and northern California populations, including plants from the Janesville area, suggest a line of gene flow may have progressed from the Great Basin westward to the Cascade-Sierra Mountains in northern California and northward into Oregon and Washington. She suggested the Janesville population be assigned ecotypic status based on its high degree of uniformity in growth habit and morphological characteristics (Alderfer 1976; Winward and Findley 1983). The ecotype’s growth habit and other attributes are retained in offsite plantings (Edgerton and others 1983; Monsen and Christensen 1975; Shaw and Monsen 1983; Shaw and others 1984a) (tables 1, 2). Figure 3—Overwintering leaves, Lassen antelope bitterbrush. Palatability and Nutrition

Lassen’s palatability and response to use have not been examined in common garden settings with other antelope Lassen is an unusual ecotype; its vegetative and floral bitterbrush populations. Livestock are grazed on native morphology is highly uniform and typical of pure ante- Lassen stands in summer. Lassen and others (1952), lope bitterbrush with little evidence of introgression with studying the Doyle mule deer (Odocoileus hemionus Stansbury cliffrose (Alderfer 1976). New leader growth Rafinesque) herd, found antelope bitterbrush constituted is pubescent. Leaves are three-lobed, gray-green to gray, 48.8 percent of mule deer stomach contents in October, and tomentose beneath. Fascicles of small, gray-green declining to 9.6 percent in January as diets shifted to big pubescent leaves persist through the winter (Shaw and sagebrush. Hormay (1943) recommended that use of an- Monsen 1986; Welch and others 1983) (fig. 3). Glands on telope bitterbrush in northeastern California be restricted leaves are rare and their density on leaders is low (Alderfer to 60 percent of current annual growth to prevent stand 1976). Decumbent branches are uncommon; layering or degredation. To preclude excessive use on any portion of root sprouting is rarely observed (Alderfer 1976; Nord the range, the California Fish and Game Commission, In- 1965; Shaw and Monsen 1983). Gland density on the terstate Deer Herd Committee (1954) suggested that av- tomentulose hypanthium is variable (Alderfer 1976). erage stand use not exceed 34 percent. Flowers have one or very rarely two pistils and a single Winter crude protein content of 8.9 percent is consid- series of approximately 25 stamens. Achenes are pubes- ered adequate for sheep and possibly mule deer (National cent and obovate. Academy of Sciences 1975; Welch and others 1983).

Table 1—Growth habit, 1977-79 grasshopper damage, and 1981 growth characteristics for one Cowania stansburiana, one Fallugia paradoxa, and eight Purshia tridentata accessions planted at the Keating Uniform Garden, Baker County, OR, in April 1976. Elevation at the Keating Garden is 980 m, annual precipitation 300 mm, and frost-free season 145 days. Soils are fine montmorillonitic, mesic Calcic Argixerolls of the Brownscombe series (from Edgerton and others 1983)

Species and Growth 1977-79 grasshopper damage 1981 growth characteristics accession habit Leaf area Bark area Height Crown Biomass Mortality ------Percent ------cm ------g Percent Cowania stansburiana American Fork, UT Erect 32 12 80 91 452 3 Fallugia paradoxa Richfield, UT Erect 37 8 103 141 497 7 Purshia tridentata Lassen, CA Erect 34 5 88 127 824 0 Boise Basin, ID Decumbent 30 2 76 138 851 0 Fort Hall, ID Semierect 42 4 61 124 490 0 Garden Valley, ID Erect 39 5 78 133 847 0 Hat Rock, OR Erect 35 5 83 144 799 0 Keating, OR Erect 38 6 78 137 867 0 Pringle Falls, OR Decumbent 87 9 47 106 164 76 Warren Mt., OR Decumbent 47 6 68 121 653 7

366 Table 2—Growth habit and 1980 growth characteristics of one Cowania stansburiana, one Fullugia paradoxa, and five Purshia tridentata accessions planted at the Boise Shrub Garden in March 1974. Elevation at the Boise Shrub Garden is 1,000 m, annual precipitation 430 mm, and frost-free season about 126 days. Soils are gravelly, sandy loams derived from granite (Shaw and Monsen 1983) Species and Growth Leader accession habit Height Crown length Shrub biomass Survival ------cm ------g Percent Cowania stansburiana American Fork, UT Erect 115 153 6.4 43 94 Fallugia paradox Richfield, UT Erect-diffuse 82 108 6.2 353 60 Purshia tridentata Lassen, CA Erect 122 175 5.2 454 96 Maybell, CO Diffuse 83 176 3.7 314 100 Lucky Peak, ID Erect-diffuse 106 191 5.2 345 100 Starvation Canyon, UT Diffuse 89 186 2.4 523 100 Eureka, UT Diffuse 108 187 5.2 372 98

Bissell and others (1955) reported crude protein content of was exceeded by only two accessions and its crude pro- antelope bitterbrush near Honey Lake was approximately tein content was exceeded by only one of these evergreen 8.8 percent in November and 9.4 percent in March. Welch accessions. and others (1983) found winter crude protein content of available browse was 15 to 34 percent greater for Lassen Insects and Disease Relationships compared to four other antelope bitterbrush populations planted in a common garden near Boise, ID (table 3). Per- Insects and microorganisms associated with Lassen cent of winter leaves equaled or exceeded values for the have received little study; investigations have centered on other four populations by as much as 156 percent, and in those considered detrimental. Organisms studied and vitro digestibility exceeded by other values by as much as plant parts affected are listed in table 4; none are specific 27 percent. Winter leafiness was 3.3 times greater for two to this ecotype. Differential use of Lassen and other ante- desert bitterbrush and one Stansbury cliffrose accession lope bitterbrush populations by several grasshopper spe- planted at this site. Lassen’s in vitro digestibility, however, cies in a northeastern Oregon common garden (Edgerton and others 1983) suggests increased knowledge of insect and microorganism relations may be essential to selecting appropriate seed sources for revegetation projects. Table 3—Winter crude protein level, winter leafiness and in vitro digestibility of winter forage samples from one Cowania stansburiana, one Fallugia paradoxa, two Purshia Seed and Planting Technology glandulosa, and five Purshia tridentata accessions grown at the Boise Shrub garden. Data expressed on a dry Nord (1965) reported antelope bitterbrush plants near matter basis (from Welch and others 1983). Within Doyle, CA, flowered in late April or early May and set columns, means followed by the same letter are not seed in early July, with an average of 62 days from flower- significantly different at the 95 percent level ing to seed ripening. Shaw and Monsen (1983) monitored Species and Crude Winter Digested Lassen plants in a common garden at an elevation of accession protein leaves dry matter 1,000 m in Ada County, ID. Floral buds appeared in April, ------Percent ------reaching anthesis in early to mid-May; seeds ripened in early July. During the 2 years of study, time from ap- Cowania stansburiana pearance of floral buds to seed set averaged 80 days. American Fork, UT 8.8cd 47.5e 37.6d Nord (1965) reported seed production of northern Fallugia paradoxa California stands, including those near Janesville, was Richfield, UT 4.8a 27.3d 29.8b strongly influenced by the previous year’s precipitation as Purshia glandulosa seeds are produced on 1-year old leaders. Leader lengths Mono Co., CA 9.3d 50.5e 37.0d and frequency of good crops were greater in areas receiv- Washington Co., UT 8.6cd 49.5e 34.6cd ing at least 250 mm of precipitation, in drainageways, in Purshia tridentata catchment basins, and where the water table was within Lassen, CA 7.9c 15.1c 30.6bc 5 to 8 m of the surface. Lucky Peak, ID 6.9b 5.9a 28.3ab Starvation Canyon, UT 6.8b 9.0abc 26.4ab Collection Eureka, UT 6.6b 13.1bc 25.2a Maybell, CO 5.9a 7.4ab 24.1a Seed collection from native Lassen stands at Janesville is facilitated by high frequencies of good seed crops,

367 Table 4—Fungi and insects associated with Lassen antelope bitterbrush Plant part Species Common name affected Reference Fungi Fusarium oxysporum Sahlecht damping-off seedlings Nelson (1987) Pithium ultimum Trow. damping-off seedlings Nelson (1987) Pithium irregulare Buisman damping-off seedlings Nelson (1987) Pithium catenulatum Matthews damping-off seedlings Nelson (1987) Insects Aulocara elliottii Thomas grasshopper leaves, twigs Edgerton and others (1983) Arphia pseudonietana Thomas grasshopper leaves, twigs Edgerton and others (1983) Melanoplus sanguinipes F. grasshopper leaves, twigs Edgerton and others (1983) Melanoplus foedus foedus Scudder grasshopper leaves, twigs Edgerton and others (1983) or M. f. fluviatilis Bruner Chlorochroa uhleri Stal stink bug seeds Nord (1965) Chlorochroa ligata Say stink bug seeds Nord (1965) Elatridae larvae wireworm seedling roots Hubbard (1956)1 Lycophotia margaritosa Haworth variegated cutworm seedlings Hubbard (1956)1 Malacosoma fragile Stretch Great Basin tent caterpillar leaves, twigs Clark (1956) caterpillar

1Described from a seeded stand near Doyle, CA. Seed origin not specified.

extensive stands, high production per plant, and ease of City, NV 89710. Certified seed may not be used to pro- collection from the large upright shrubs (Alderfer 1976; duce seedlings for establishment of certified seed orchards. Nord 1962, 1965). Cleaned seeds from Lassen plants in • Certified seedlings—Seedlings produced from certi- California and Idaho average about 35,000/kg (Nord 1956; fied seed may be certified for commercial sales. Shaw and others 1984a). Private seed dealers and State and Federal agencies have collected large quantities of seed from the Janesville site for use in revegetation pro- Native Lassen Stands jects in northern California and throughout the West, making it one of the major antelope bitterbrush seed col- The recent history of the Doyle mule deer winter range lection centers in some years (Shaw and Monsen 1986). parallels that of many other mule deer winter ranges Seed availability has been reduced in recent years due dominated by antelope bitterbrush, but has been more to extensive wildfires and stand loss. thoroughly documented than most. The California De- partment of Fish and Game initiated a major study of this Certification range in 1948 in response to concerns over the degredation of northeastern California mule deer winter ranges result- Release of Lassen permits verification of seed origin ing from excessive browsing by livestock and mule deer, through cooperation with State seed certification agen- drought, and wildfires (Lassen and others 1952). They cies. Recognized classes of seed and plant materials for were later joined by the Nevada Fish and Game Commis- this release are foundation and certified (Shaw and others sion, the U.S. Department of Interior, Bureau of Land 1984a,b; Soil Conservation Service 1986). There is no reg- Management, and the U.S. Department of Agriculture, istered seed or plant materials class. Forest Service in forming the Lassen-Washoe Interstate Deer Study Committee. Documentation of overstocked • Foundation seed—Parent plants for the Lassen re- deer populations, poor herd health, and decadent, heavily- lease are protected in a fenced exclosure near Janesville browsed populations of major forage species with little re- maintained by the California Department of Fish and generation led to recommendations for major changes in Game. Foundation seed is harvested from this exclosure. deer herd management and regulation (see, for example, • Certified seed—Seed harvested from wildland stands Bissell and others 1955; Bissell and Strong 1955; Dasmann in an area between Doyle and Susanville may be certified and Blaisdell 1954; Dasmann and Hjersman 1958; Lassen for commercial sales. Seed collectors should contact the and others 1952; Leach 1956; Longhurst and others 1952). California Crop Improvement Association, 231 Hunt Hall, Research conducted through a cooperative agreement University of California, Davis, CA 95616, for information between the California Department of Fish and Game and regarding certification procedures and costs. Certified the U.S. Department of Agriculture, Forest Service, South- seed may also be harvested from certified seed orchards. west Forest and Range Experiment Station initiated in • Foundation seedlings—Seedlings are produced from 1952 contributed to development of site preparation, plant- foundation seed for establishment of certified seed or- ing, and stand management practices for the reestablish- chards. Foundation seedlings are available from the ment of antelope bitterbrush in northeastern California Nevada Division of Forestry, 201 S. Fall Street, Carson and throughout its range (Hubbard 1962, 1964; Hubbard and McKeever 1961; Hubbard and others 1959; Neal and

368 Sanderson 1975; Sanderson and McIntosh 1961). Seeds seed collections. This program provides verification of for many of these studies were harvested near Janesville seed origin if direct supervision of seed collection by the (Hubbard 1983; Neal 1983; Sanderson 1983), and several user is not possible. Additional information on procedures study sites were located in this area. and costs can be obtained from State seed certification Factors contributing to the decline and loss of mature agencies. The development of additional antelope bitter- antelope bitterbrush stands on this range have also inhib- brush varietal releases or the intermediate categories of ited regeneration (Hormay 1943; Nord 1965; Updike and tested or selected seeds and plant material may depend others 1990; Young and Evans 1981). Sanderson (1962) on the level of demand for improved or agriculturally pro- and Nord (1965) reported native seedlings established duced seed. only infrequently. Sanderson (1962) found native seedlings on a site near Doyle established primarily from rodent caches, with survival greatest on sites with limited References competition for moisture. Hubbard and Sanderson (1961) and Young and others (1972) noted one consequence of Alderfer, Jean Marie. 1976. A taxonomic study of bitter- summer wildfires was the proliferation of cheatgrass brush (Purshia tridentata [Pursh] DC.) in Oregon. and a reduction in natural antelope bitterbrush seedling Corvallis, OR: Oregon State University. 197 p. Thesis. recruitment. Association of Official Seed Certification Agencies. 1991. During the 1980’s, critically important antelope bitter- Pre-variety germ plasm certification standards. Unpub- brush stands in the Doyle mule deer winter range were lished document on file at: U.S. Department of Agricul- fragmented and fire suppression efforts were complicated ture, Forest Service, Forestry Sciences Laboratory, by rural housing development (Hall 1992; Updike and Boise, ID. 6 p. others 1990). Substantial antelope bitterbrush stands Basile, Joseph V. 1967. An annotated bibliography of bit- were consumed by wildfires during this period. Remain- terbrush (Purshia tridentata [Pursh] DC.) Res. Pap. ing antelope bitterbrush stands have been mapped and INT-44. Ogden, UT: U.S. Department of Agriculture, digitized in a Geographic Information System to provide Forest Service, Intermountain Forest and Range Ex- data needed by wildlife managers, land use planners, and periment Station. 27 p. fire suppression officials to aid in protecting the remain- Bissell, Harold D.; Harris, Bruce; Strong, Helen; James, ing stands (Hall 1992). Stand fragmentation was one fac- Frank. 1955. The digestibility of certain natural and tor leading to the decision to release Lassen as a named artificial foods eaten by deer in California. California variety. Fish and Game. 41: 57-78. Bissell, Harold D.; Strong, Helen. 1955. The crude protein variations in the browse diet of California deer. California Fish and Game. 41: 145-155. Future Use California Fish and Game Commission, Interstate Deer The release of named varieties provides users with a Herd Committee. 1954. Eighth progress report on the cooperative study of the Devil’s Garden interstate deer comprehensive data summary, procedures for verification herd and its range. California Fish and Game. 40: of seed origin, and regulations for maintaining the genetic 235-266. identity of agriculturally produced seed. The variety re- Clark, Edwin C. 1956. The Great Basin tent caterpillar lease process, however, is rather costly, slow, and com- in relation to bitterbrush in California. California Fish plex. It is not a viable approach for dealing with the and Game. 42: 131-143. many wildland populations of antelope bitterbrush and Clark, Robert G.; Britton, Carlton M. 1979. A bibliogra- other species. phy of bitterbrush (Purshia tridentata [Pursh] DC.) An- The accumulated literature on antelope bitterbrush notated from 1967 to 1978. Stn. Bull. 640. Corvallis, (see, for example, Meyer 1989; Tiedemann and Johnson OR: Oregon State University, Agricultural Experiment 1983 and bibliographies by Basile 1967; Clark and Britton Station. 18 p. 1979; and Hall 1964) plus unpublished data and reports Dasmann, W. P.; Blaisdell, J. P. 1954. Deer and forage re- provide a basis for describing additional commonly col- lationship on the Lassen-Washoe interstate winter deer lected populations and their ranges of adaptability. There range. California Fish and Game. 40: 215-234. is a need to consolidate performance data for the most fre- Dasmann, W. P.; Hjersman, H. A. 1958. Deer survival quently harvested populations in publications or data- and range forage trends on eastern California winter bases to aid in selecting seed sources and developing seed ranges. California Fish and Game. 44: 51-72. transfer guidelines. Davis, James N. 1983. Performance comparisons among The Association of Official Seed Certification Agencies populations of bitterbrush, cliffrose, and bitterbrush- has developed standards for four classes of wildland plant cliffrose crosses on study sites throughout Utah. In: seeds representing increasing degrees of certainty of seed Tiedemann, Arthur R.; Johnson, Kendall L., comps. source origin (Association of Official Seed Certification Proceedings—research and management of bitterbrush Agencies 1991). These range from site-identified seed of and cliffrose in western North America; 1982 April nonselected populations for which certification involves 13-15; Salt Lake City, UT. Gen. Tech. Rep. INT-152. field verification of origin to the seed categories (breeder, Ogden, UT: U.S. Department of Agriculture, Forest foundation, registered, and certified) developed for varietal Service, Intermountain Forest and Range Experiment releases. Most State seed certification agencies will now Station: 38-44. provide site-identified certification services for wildland Edgerton, Paul J.; Geist, J. Michael; Williams, Wayne G.

369 1983. Survival and growth of Apache-plume, Stansbury Lassen, R. W.; Ferrel, C. M.; Leach, H. 1952. Food habits, cliffrose, and selected sources of antelope bitterbrush in productivity, and condition of the Doyle mule deer herd. northeast Oregon. In: Tiedemann, Arthur R.; Johnson, California Fish and Game. 38: 211-224. Kendall L., comps. Proceedings—research and manage- Leach; H. R. 1956. Food habits of the Great Basin deer ment of bitterbrush and cliffrose in western North herds of California. California Fish and Game. 42: America; 1982 April 13-15; Salt Lake City, UT. Gen. 243-308. Tech. Rep. INT-152. Ogden, UT: U.S. Department of Longhurst, W. M.; Leopold, A. S.; Dasmann, R. F. 1952. A Agriculture, Forest Service, Intermountain Forest and survey of California deer herds, their ranges, and man- Range Experiment Station: 45-54. agement problems. Bull. 6. Sacramento, CA: California Giunta, Bruce C.; Stevens, Richard; Jorgensen, Kent R.; Department of Fish and Game. 136 p. Plummer, A. Perry. 1978. Antelope bitterbrush—an im- McArthur, E. Durant. 1982. [Personal communication]. portant wildland shrub. Publ. 78-12. Salt Lake City, Provo, UT: U.S. Department of Agriculture, Forest Ser- UT: Utah State Division of Wildlife Resources. 48 p. vice, Intermountain Research Station, Shrub Sciences Hall, Frank. 1992. Bitterbrush mapping project: Janesville/ Laboratory. Bass Hill/Susan Hills, Lassen County, California, Spring McArthur, E. Durant; Stutz, Howard C.; Sanderson, 1992. Unpublished document on file at: U.S. Depart- Stewart C. 1983. Taxonomy, distribution, and cytoge- ment of Agriculture, Forest Service, Intermountain netics of Purshia, Cowania, and Fallugia (Rosoideae, Research Station, Boise, ID. 3 p. Rosaceae). In: Tiedemann, Arthur R.; Johnson, Kendall L., Hall, Frederick C. 1964. Literature review of bitterbrush. comps. Proceedings—research and management of bit- Unpublished document on file at: U.S. Department of terbrush and cliffrose in western North America; 1982 Agriculture, Forest Service, Intermountain Forest and April 13-15; Salt Lake City, UT. Gen. Tech. Rep. INT-152. Range Experiment Station, Forestry Sciences Labora- Ogden, UT: U.S. Department of Agriculture, Forest Ser- tory, Boise, ID. 48 p. vice, Intermountain Forest and Range Experiment Sta- Hormay, August L. 1943. Bitterbrush in California. For. tion: 4-24. Res. Notes 34. Berkeley, CA: U.S. Department of Agri- Meyer, S. E. 1989. Warm pretreatment effects on antelope culture, Forest Service, California Forest and Range bitterbrush (Purshia tridentata) germination response Experiment Station. 12 p. to chilling. Northwest Science. 63: 146-153. Hubbard, Richard L. 1956. Bitterbrush seedlings de- Monsen, Stephen B. 1987. Shrub selections for pinyon- stroyed by cutworms and wireworms. For. Res. Notes juniper plantings. In: Everett, Richard L., comp. 114. Berkeley, CA: U.S. Department of Agriculture, Proceedings—pinyon-juniper conference; 1986 January Forest Service, California Forest and Range Experi- 13-16; Reno, NV. Gen. Tech. Rep. INT-215. Ogden, UT: ment Station. 2 p. U.S. Department of Agriculture, Forest Service, Inter- Hubbard, Richard L. 1962. The place of browse seeding mountain Research Station: 316-329. in game range management. Twenty-seventh North Monsen, Stephen B.; Christensen, Donald R. 1975. American wildland natural resources conference trans- Woody plants for rehabilitating rangelands in the Inter- actions. 1962: 394-401. mountain Region. In: Stutz, H. C., ed. Wildland shrubs: Hubbard, Richard L. 1964. A guide to bitterbrush seeding proceedings—symposium and workshop; 1975 November in California. Berkeley, CA: U.S. Department of Agri- 4-7; Provo, UT: Brigham Young University: 72-119. culture, Forest Service, Pacific Southwest Forest and Monsen, Stephen B.; Davis, James N. 1986. Progress in Range Experiment Station. 30 p. the improvement of selected western North American Hubbard, Richard L. 1983. [Personal communication]. rosaceous shrubs. In: Carlson, J. R.; McArthur, E. D., Berkeley, CA: U.S. Department of Agriculture, Forest chairmen. Range plant improvement in western North Service, Southwest Forest and Range Experiment America. In: Proceedings—selected papers presented at Station. the 38th annual meeting of the Society for Range Man- Hubbard, Richard L.; McKeever, Sturgis. 1961. Meadow agement; 1985 February 11-15; Salt Lake City, UT. mouse girdling—another cause of death of reseeded bit- Denver, CO: Society for Range Management: 201-209. terbrush plants. Ecology. 42: 198. National Oceanic and Atmospheric Administration. 1982. Hubbard, Richard L.; Nord, Eamor C.; Brown, Lyle L. Monthly normals of temperature, precipitation, and 1959. Bitterbrush reseeding—a tool for the game range heating and cooling degree days 1951-80. California. manager. Misc. 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Ogden, UT: Young, James A.; Evans, Raymond A. 1981. Demography U.S. Department of Agriculture, Forest Service, Inter- and fire history of a western juniper stand. Journal of mountain Forest and Range Experiment Station. 4 p. Range Management. 34: 501-506.

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