This file was created by scanning the printed publication. Errors identified by the software have been corrected; however, some errors may remain. HISTORY AND APPLICATIONS OF THE INTERMOUNTAIN GREENSTRIPPING PROGRAM Mike Pellant between fire frequency and relative frequency of cheatgrass in southern Idaho. Greater fire frequencies were also found to cause lower species richness in native communities. The trend of increased wildfire frequency on cheatgrass rangelands observed by Stewart and Hull (1949) is continuing today (Pellant 1990). Cheatgrass was recognized as an "ecologic intruder" as early as 1949 (Stewart and Hull 1949) and is now a major component of the vegetation on over 17 million acres of Great Basin rangelands (Pellant, in press). The ecological and economic implications of the invasion of cheatgrass and other alien weeds and the concurrent increase in wildfires are enormous (Young and others 1987). The adverse impacts of cheatgrass expansion and wildfire increases in the Intermountain area have recently received national attention in a popular magazine (Devine 1993). Although many consider this region a "lifeless desert," these rangelands support a wide variety of wildlife and plant species, provide watershed and recreation values, and support an important livestock industry. A proactive wildfire management approach to reduce wildfire impacts on natural and fiscal resources was needed to maintain the character and ecosystem functions in the Intermountain area. The use of fire-resistant vegetation (greenstripping) to reduce wildfire spread offered an alternative to reverse this trend. ABSTRACT The size and frequency of wildfires are rapidly increas- in8 on rangelands in the Intermountain area of the Western United States. One of the major contributors to increased wildfires is alien annual grasses, primarily cheatgrass (Bromus tectorum). Because these annual grasses dry earlier than native species and are highly flammable, they promote the rapid spread of fire. To reduce the size and impact of rangeland wildfires, a wildfire presuppression program called "greenstripping• was initiated in IOOho by the Bureau ofLand Management in 1985. Greenstripping is the strategic placement of30- to 400-ft-wide strips of fire-resistant vegetation on fire-prone landscapes. To date, 461 mi (16,280 acres) of experimental and operational greenstrips have been established. The objectives of the greenstripping program include protecting native rangelands and private properties from wildfire damage, as well as reducing fire suppression and rehabilitation costs. INTRODUCTION Wildfire impacts are of increasing concern to resource managers and the public in the Great Basin Desert (northem Nevada, eastern Oregon, southern Idaho, and western Utah) of the Intermountain West. Historically, wildfires occurred at return intervals of 32-70 years in sagebrush (Artemisia sp.) vegetation types in the Great Basin (Wright and others 1979). However, the frequency and size of wildfires today is considerably higher than historical levels. Between 1984 and 1993, 2,909 wildfires burned 1,956,840 acres of rangeland in Idaho alone (USDI 1993). Conversion of native, shrub-steppe vegetation to annual grasses was initiated in the mid-1800's with overgrazing by domestic livestock (Yensen 1980). A significant reduction in native herbaceous vegetation occurred and, concurrently, alien annual species were introduced and soon dominated large areas within the Intermountain area (Young and others 1972). CheatgraSB is a wildfire hazard because it matures earlier than native species and provides easily ignited fuels that promote a rapid rate offirespread (Stewart and Hull 1949). Whisenant (1990) found a significant correlation BACKGROUND The concept of using vegetation that resists burning as a tool to reduce wildfire spread is not new. Early researchers working with crested wheatgrass (Agropyron cristatum and A. sibericum) in southern Idaho recognized the value of this introduced, perennial grass in lessening the cheatgrass fire hazard (Hull and Stewart 1948; Stark and others 1947). The practical benefit of crested wheatgrass as a fire control tool was recognized after an August 1949 wildfire northeast of Shoshone, ID. A 15,000-acre wildfire burned to the perimeter of a crested wheatgrass seeding and stopped, prompting the Bureau of Land Management (BLM) fire control officer to report, "The reseeded area of Owinza Butte, which has a good stand of crested wheat, shows without doubt the value of this type of planting in fire control work" (USDI 1948). The establishment of vegetative fuel breaks in cheatgrass rangelands was proposed in 1946 in Oregon (Platt and Jackman 1946). These authors suggested that cheatgrass rangelands be broken at suitable intervals, especially along highways, with "strip plantings" of fireresistant vegetation such as crested wheatgr888. Paper presented at the Symposium on Ecology, Management, and Restoration of Intermountain Annual Rangelands, Boise, ID, May 18-22, 1992. Mike Pellant is an Ecologist and Greenstrip Program Manager, U.S. Department of the Interior, Bureau of Land Management, Idaho State Office, 3380 Americana Terrace, Boise, ID 83706. 63 PROGRAM OBJECTIVE Bureau of Land Management personnel in Idaho first applied the concept of planting fire-resistant vegetation along roadways in 1981-82 in the Shoshone District. A 25-mi system of crested wheatgrass "roadstrips" was planted after a large wildfire (USDI 1982). Establishment of crested wheatgrass was poor because of annual grass competition and large expanses of rocky, shallow soils in the treatment area. However, results from early research and wildfire contacts with aeedings were sufficiently promising that the BLM decided in 1985 to incorporate the use of fire-resistant vegetation into its Emergency Fire Rehabilitation program to reduce future fire occurrences after an initial fire (USDI 1985). The establishment of vegetative fuel breaks to reduce wildfire spread is not limited to the Great Basin area. In 1957, the "Fuel-Break Research and Demonstration Program" was organized in southern California to expand construction of wide fuel breaks in chaparral areas (Green 1977). Planting perennial grasses that remain green into the summer was recommended for California firebreaks. The objective of the greenstripping program is to slow or atop the spread of wildfires by the strategic placement of strips of fire-resistant vegetation on the landscape (fig. 1). By reducing wildfire frequency and size, the following benefits are realized: 1. Reduced loss of plant diversity and shrub cover on sagebrush-steppe and salt-desert shrublands. With longer intervals between wildfires, loss of plant diversity, especially shrubs, will be slowed on fire-prone landscapes and eventually native species may increase (West 1978; Whisenant 1990; Young and Evans 1978). 2. Reduced loss of private structures and properties on urban/rural interfaces with public rangelands. 3. Reduced fire suppression and rehabilitation costa. FUELS MANAGEMENT STRATEGY Vegetative fuelbreaks, including greenatripa, are simply fuels modification actions whereby vegetation that is susceptible to igniting and carrying a fire is replaced by vegetation that is less likely to ignite or carry a wildfire. Standing dead material and current growth of plants and litter constitute the bulk of rangeland fuels. Fuels are the only element of the fire behavior triangle that can be influenced by management actions, as neither weather nor topography are easily manipulated. By modifying fuel properties, extreme fire behavior can be reduced. Fuels available for combustion depend on the proportion of fuel that is dead, fuel particle size, moisture content, and fuel continuity (Anderson and Brown 1988). With other factors being equal, the likelihood of a fire start and rate of fire spread increases as fuel availability BEGINNING OF THE GREENSTRIPPING PROGRAM In 1985, Idaho BLM personnel initiated the greenstripping program to reduce the impacts of wildfires. Strips of fire-resistant vegetation are planted at strategic locations on the landscape to slow or stop wildfires. The previous section clearly indicates that the use of fire-resistant vegetation to reduce wildfire impacts is not a new concept. Why did BLM initiate this new wildfire presuppression program? The answer is simple: to incorporate improved plant materials and new seeding and site preparation equipment and technology into the implementation of a vegetative fuel-break program. Greenstripping, a proactive approach to wildfire management, was implemented to augment the reactive programs of fire suppression and Emergency Fire Rehabilitation (Pellant 1990). In 1987, two tasks were accomplished to formally implement the greenstripping program. Firat, an interagency workgroup completed a handbook that identified greenstrip criteria and procedures (USDI 1987). Second, Congressional funding was obtained to establish operational greenatrip projects and implement a cooperative research program. Goals of the BLM's Intermountain Greenstripping and Rehabilitation Research Project are to evaluate and select fire-resistant plant materials and equipment to improve greenstripping and fire rehabilitation practices. Six research cooperators are currently working to accomplish these goals. In 1991, an internal evaluation of the greenstripping program recommended program expansion to public land in Utah, Oregon, and Nevada (USDI 1991). Pilot greenstrip projects were established in these three States in 1992-93, and multistate coordination on greenstrip projects and research continues to this day. The author provides technical assistance about greenstrip planning and implementation to other land managers in the Intermountain area. Figure 1-This greenstrip project near Mountain Home, ID, was seeded with crested wheatgrass in 1985. Seedbed preparation on this 30-ft-wide greenstrip was done with road patrol to reduce weedy plant competition. Note absence of cheatgrass in interspaces in this 1992 photo. 64 increases. Rangelands infested with alien, annual grasses are more prone to ignition and fire spread than native rangelands, since the proportion of available, contiguous fuels is higher on the former than the latter. The effectiveness of greenstrips, or any fuels modification project, in reducing wildfire spread is enhanced by three factors: Disrupting Fuel Continuity-Fuel continuity can be disrupted by replacing cheatgrass or other annual grasses, which grow in a matlike pattern, with caespitose grasses such as crested wheatgrass, which h ave large spaces between individual plants (fig. 1). Spread of surface fires is interrupted in discontinuous fuels a nd can be more easily suppressed (Anderson and Brown 1988). Reducing Fuel Accumulations and VolatilityRangelands with a high density of shrubs generate longer flame lengths and increase the probability of fire spotting (Schmidt and Wakimoto 1988). The high monoterpene and sesquiterpene content of sagebrush (Kelsey 1986) increases fire intensity in shrubs. Fire suppression actions are easier and safer to carry out in light fuels than in heavy fuels; for example, backfiring is less risky in perennial herbaceous vegetation than in dense stands of shrubs. The probability of fires spreading laterally can be greatly reduced if shrub stands are thinned to maintain a minimum distance of 10 ft between plants (Schmidt and Wakimoto 1988). Figure 2-Forage kochia plant (foreground) in a marginally established greenstrip near Mountain Home, 10 . Forage kochia is still green in this August 1990 photograph. A wildfire started off Interstate 84 (background) burned to this greenstrip and stopped because of the sparsity of contiguous fine fuels in the seeding. watershed, and cultural and plant communities that are at risk if disturbed. Both fire history and potential for repeated wildfires are also considered. High fire-frequency areas are generally associated with cheatgrass and tend to reburn at frequent intervals (Whisenant 1990). Greenstripping can break large blocks of cheatgrass-infested rangeland into smaller, more manageable units, thereby reducing fire suppression costs and spread of wildfires into unburned shrublands. Increasing the Density of Plants With a Higher Moisture Content-The length of time during the fire season that fuels and fire behavior remain hazardous and ignition potential is high is largely reflected in the moisture content of the various species in the plant community (Anderson and Brown 1988). Increasing the proportion of plants with high moisture and low volatile oil content can reduce both the potential for ignition and rate of fire spread. Forage kochia (Kochia prostrata ), an introduced half shrub, was found to have a fourfold and tenfold higher moisture content in August 1992 than crested wheatgrass and cheatgrass, respectively (USDI 1992). This plant is effective in retarding wildfire spread and can compete well in a weedy environment (fig. 2). Land Ownership Land ownership patterns are an important consideration in greenstrip planning. Greenstripping across "checkerboard" land ownership patterns requires easements from private or State land owners. "Gaps" left in greenstrips due to the presence of nonfederalland can severely limit the effectiveness of a greenstrip in stopping or slowing a wildfire. PLANNING AND IMPLEMENTATION A host of factors must be considered in the planning and implementation of a greenstrip project. The use of an interdisciplinary team that "designs" a greenstrip based on a site-specific evaluation is essential. The following factors should be considered when designing and implementing a greenstrip project. Fire Behavior Topography, vegetation types (fuel loads), and weather patterns are fire behavior characteristics that must be evaluated and incorporated into locating greenstrips on the landscape. Expected fire behavior is included in the design of a greenstrip project by considering prevailing wind direction, slope, and fuel qua ntities and continuity. Fire management specialists are included in the planning process to ensure proper consideration of fire behavior variables in selecting greenstrip locations. Project Area Selection of sites to implement greenstripping projects is determined by an interdisciplinary team. This team reviews land-use plans that identify high-value habitat, 65 greenstrip project boundaries and compete with native plants. Fourwing saltbush (Atriplex canescens), a native shrub, is occasionally used to enhance diversity of greenstrips and to trap winter snowfall. Soils Soil productivity and the amount of surface rock affect seeding establishment and persistence. Deeper soils generally support a better stand of seeded vegetation than do rocky, shallow soils. Therefore, greenstrip width is increased to compensate for reduced density of greens trip species on rocky or shallow soils. Site Preparation and Seeding Most sites selected for greenstripping are dominated by weedy species such as cheatgrass, either as an annual grass monoculture or as the dominant understory species under sagebrush. Site preparation to reduce competition from annual plants is required prior to seeding perennial vegetation (Evans and Young 1977; Stark and others1947). Evans (1961) reported that cheatgrass densities as low as 64 plants per square foot greatly increased mortality of crested wheatgrass seedlings. Mechanical, herbicidal, and burning treatments (or combinations of them) are effective in controlling annual species under the right conditions. Mechanical seedbed preparation techniques have been used extensively and evaluated in the greenstripping program. Disking is most effective if the treatment is done in early spring prior to cheatgrass seed maturity (fig. 3). Seeding greenstrip species with a rangeland drill is done in the fall following the disking treatment. Labor and equipment costs to mechanically prepare seedbeds and distribute seed were estimated at $20 to $25 per acre by Pellant (1990). Hereports that these costs are considerably reduced ($8.50 per acre for labor ) with the use of a disk chain that buries unwanted vegetation and distributes seed in one pass. Use of fire as a site preparation technique can be effective if burning is done prior to seed dispersal by cheatgrass (Hull and Stewart 1948; Pechanec and Hull1945). Costs to burn cheatgrass rangelands are generally under $5 per acre. Greenstrip Width Greenstrip width generally varies from 30 to 400 ft depending on fire prevention objectives, topography, expected fire behavior, and soils. Most greenstrip projects in Idaho average 300 ft in width and have been seeded along highways or railroads to reduce human-caused fire starts and create a wider fire barrier. As fuel height and volatility increase, greenstrip width should be increased to reduce the potential for fire spotting that may occur over the greenstrip. Visual Impacts Greenstrips can have a significant impact on the visual characteristics of a landscape. Adverse visual impacts can be minimized by avoiding straight-line seedings and increasing plant and structural diversity in greenstrip plantings. Plant Materials The selection of proper seed mixtures for greenstrip plantings is critical for the successful establishment and persistence of seeded species. General criteria for selecting species for rehabilitation are discussed by Plummer and others (1968). Extensive research on reseeding abandoned farmland (Stark and others 1946) and cheatgrassinfested rangelands (Hull and Stewart 1948; Hull and Holmgren 1964; lGomp and Hull 1971) is available for planning greenstrip projects. Plants selected for seeding greenstrip projects should also be: 1. Fire resistant during a majority of the wildfire season. 2. Drought tolerant and adapted to persist on semiarid sites. 3. Palatable to herbivores. 4. Fire tolerant to survive occasional burns. 5. Capable of establishing and persisting in competition with a nnual species. Plant materials meeting all of these criteria are not readily available. Introduced wheatgrasses (Agropyron sp.), Russian wildrye (Elymusjunceus), dryland alfalfa (Medicago sp.), Lewis flax (Linum lewisii), and small burnett (Sa nguisorba minor) are the most common herbaceous species seeded in greenstrip projects. Shrubs generally increase fuel loads and flammability, increasing the probability that a greenstrip could be breached by a wildfire. Therefore, use of shrubs in greenstrips is minimal. One exception is forage kochia, which is limited in use only by seed availability and cost. There are also concerns that this plant may spread outside of Figure 3-Towner plow used to reduce annual plant competition in May 1993 on a greenstrip project near New Plymouth, ID. Rangeland drills were used to plant a diverse greenstrip mixture in October 1993. 66 Herbicides offer another alternative for cheatgrass control prior to seeding (Eckert and others 1974). Several herbicides are being field tested in Idaho and Nevada to determine their effectiveness in reducing cheatgrass competition. Twenty-one herbicides are approved for use on public land to meet specific vegetation treatment objectives (USDI 1991). Economics, environmental impacts, selectivity, and effectiveness are several of many factors that must be cOnsidered prior to selecting an herbicide for site preparation in cheatgrass-infested rangelands. In many respects, this situation is little changed 28 years later. Therefore, it is probable that wildfire impacts will continue to increase unless proactive measures, such as greenstripping, are applied. Greenstripping is not the ultimate solution to the cheatgrass-wildfire problem, but one of many tools that must be applied to control wildfires on rangelands dominated by annual plants. ACKNOWLEDGMENTS The author thanks Idaho BLM personnel who initiated and contributed to the development of the greenstripping program. Sue Phillips greatly improved the structure and organization of this manuscript, while Bob Clark, Steve Monsen, and Don Smurthwaite added editorial reviews. Management Livestock season-of-use and wildlife use patterns must be considered in greenstrip planning. Livestock and wildlife are often attracted to green vegetation, causing overuse and eventual loss of palatable greenstrip plants. Additionally, greenstrips along roads or railways may attract livestock and wildlife to the road or track, causing accidents. An adequate period ofherbivore exclusion during the plant establishment period is also essential. Seeding prescriptions for greenstrips should only include species that will establish during the grazing exclusion period and species that will not be selectively overgrazed and eventually lost from the greenstrip. However, livestock can serve a useful role in proper greenstrip management by reducing fine fuels through grazing and trampling. REFERENCES Anderson, Hal E.; Brown, James K. 1988. Fuel characteristics and fire behavior considerations in the wildlands. In: Fischer, William C.; Amo, Stephen F., camps. Protecting people and homes from wildfire in the Interior West: proceedings of the symposium and workshop; 1987 October 6-8; Missoula, MT. Gen. Tech. Rep. INT-251. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 124-130. Bunting, S. C. 1985. Fire in sagebrush-grass ecosystems: successional changes. In: Sanders, Ken; Durham, Jack, eds. Rangeland fire effects-a symposium; 1984 November 27-29; Boise, ID. Boise, ID: U.S. Department of the Interior, Bureau of Land Management, Idaho State Office: 7-11. Devine, Robert. 1993. The cheatgrass problem. The Atlantic. 271(5): 40-48. Eckert, R. E., Jr.; Asher, J. E.; Christensen, M. D.; Evans, R. A. 1974. Evaluation of the atrazine-fallow technique for weed control and seeding establishment. Journal of Range Management. 27: 288-292. Evans, R. A. 1961. Effects of different densities of downy brome (Bromus tectorum) on growth and survival of crested wheatgrass (Agropyron desertorum) in the greenhouse. VVeeds.9:216-223. Green, L. R. 1977. Fuelbreaks and other fuel modifications for wildland fire control. Agric. Handb. 499. Washington, DC: U.S. Department of Agriculture, Forest Service. 31 p. Hull, A. C., Jr. 1965. Cheatgrass-a persistent homesteader. In: Proceedings, cheatgr888 symposium; 1965 July 27-30; Vale, OR. Portland, OR: U.S. Department of the Interior, Oregon Bureau of Land Management: 20-26. Hull, A. C., Jr.; Holmgren, R. C. 1964. Seeding southern Idaho rangelands. Res. Pap. INT-10. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 31 p. Hull, A. C., Jr.; Stewart, G. 1948. Replacing cheatgrasss by reseeding with perennial grass on southern Idaho ranges. American Society of Agronomy Journal. 40: 694-703. Kelsey, Rick G. 1986. Foliage biomass and crude terpenoid productivity of big sagebrush <Artemisia tridentata). PROGRAM STATUS From 1985 to the end of 1993, 451 mi (16,280 acres) of greenstrips were seeded on public land in Idaho (PeDant 1993). Pilot greenstrip projects were completed in Oregon, Nevada, and Utah in 1992 with technical assistance from the Idaho Greenstrip Program Manager. Two wildfires have burned into established greenstrip projects. In 1988, a greenstrip project north of Grasmere, ID, was effective in stopping a wildfire along 6 of 7 mi of the contact area. This allowed suppreBBion forces to concentrate their efforts on a fire front of only 1 mi instead of7. In 1990, a greenstrip adjacent to a major interstate highway near Mountain Home, ID, limited a wildfire to 15 acres (fig. 3). From 1980 to 1989, the average area burned in the same vicinity was 1,800 acres. The Intermountain Greenstripping and Rehabilitation Research Project has been transferred to the Department of the Interior's National Biological Survey. Research is continuing in 1994. SUMMARY The Intermountain landscape has been permanently altered by the introduction and spread of alien annual species, especially cheatgrass, which are more competitive and flammable than native species. In 1965, a group of land managers and research specialists met in Vale, OR, to di8CU88 solutions to the management problems posed by cheatgrass. Noted revegetation researcher, A. C. Hull, Jr., summed up the situation by stating, "The more cheatgrass the more fire, and the more fire the more cheatgrass" (USDI 1965). 67 In: McArthur, E. Durant; Welch, Bruce L., comps. Proceedings-symposium on the biology of Artemisia and Chrysothamnus; 1984 July 9-13; Provo, UT. Gen. Tech. Rep. INT-200. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 375-388. Pechanec, J. F.; Hull, A. C., Jr. 1945. Spring forage lost through cheatgrass fires. National Wool Grower. 35: 13. Pellant, M. 1993. [Unpublished data]. On file at: Bureau of Land Management, Idaho State Office, Boise, ID. Pellant, Mike. 1990. The cheatgrass-wildfire cycle-are there any solutions? In: McArthur, E. Durant; Romney, Evan M.; Smith, Stanley D.; Tueller, Paul T., comps. Proceedings-symposium on cheatgrass invasion, shrub die-off, and other aspects of shrub biology and management; 1989 April 5-7; Las Vegas, NV. Gen. Tech. Rep. INT-276. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 11-17. Platt, Kenneth; Jackman, E. R. 1946. The cheatgrass problem in Oregon. Bull. 668. Corvallis, OR: Oregon Agricultural Experiment Station. 48 p. Plummer, A. P.; Christensen, D. R.; Monsen, S. B. 1968. Restoring big game range in Utah. Publ. 68-3. Salt Lake City, UT: Utah Division of Fish and Game. 183 p. Schmidt, Wyman C.; W akimoto, Ronald H. 1988. Cultural practices that can reduce fire hazards to homes in the Interior West. In: Fischer, William C.; Arno, Stephen F., comps. Protecting people and homes from wildfire in the Interior West: proceedings of the symposium and workshop; 1987 October 6-8; Missoula, MT. Gen. Tech. Rep. INT-251. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 131-141. Stark, R. H.; Toevs, J. L.; Hafenrichter, A. L. 1946. Grasses and cultural methods for reseeding abandoned farmlands in southern Idaho. Bull. 267. Moscow, ID: Idaho Agricultural Experiment Station. 36 p. Stewart, G.; Hull, A. C., Jr. 1949. Cheatgrass {Bromus tectorum L.)-an ecologic intruder in southern Idaho. Ecology. 30(1): 58-74. U.S. Department of the Interior, Bureau of Land Management. 1949. [Unpublished fire control records]. Shoshone, ID: U.S. Department of the Interior, Bureau of Land Management, Shoshone District Office. 7 p. U.S. Department of the Interior, Bureau of Land Management. 1982. Unpublished fire rehabilitation records. Shoshone, ID: U.S. Department of the Interior, Bureau of Land Management, Shoshone District Office. 10 p. U.S. Department of the Interior, Bureau of Land Management. 1985. Emergency fire rehabilitation-BLM Manual Handbook H-7142-1. Washington, DC: U.S. Department of the Interior, Bureau of Land Management. 9p. U.S. Department of the Interior, Bureau of Land Management. 1987. Draft greenstripping handbook. Boise, ID: U.S. Department of the Interior, Bureau of Land Management, Idaho State Office. 80 p. U.S. Department of the Interior, Bureau of Land Management. 1991. Special evaluation for Intermountain Greenstripping and Rehabilitation Research Project. Boise, ID: U.S. Department of the Interior, Bureau of Land Management, Idaho State Office. 10 p. U.S. Department of the Interior, Bureau of Land Management. 1991. Record of decision-vegetation treatment on BLM lands in thirteen western states. Boise, ID: U.S. Department of the Interior, Bureau of Land Management, Idaho State Office. 17 p. U.S. Department of the Interior, Bureau of Land Management. 1993. 1993 fire statistical summary. Boise, ID: U.S. Department of the Interior, Bureau of Land Management, Idaho State Office. 27 p. West, N. E. 1979. Basic synecological relationships of sagebrush-dominated lands in the Great Basin and Colorado Plateau. In: The sagebrush ecosystem: a symposium; 1978 April27-28; Logan, UT. Logan, UT: Utah State University, College ofNatural Resources: 33-41. Whisenant, Steven G. 1990. Changing fire frequencies on Idaho's Snake River Plains: ecological and management implications. In: McArthur, E. Durant; Romney, Evan M.; Smith, Stanley D.; Tueller, Paul T., comps. Proceedings-symposium on cheatgrass invasion, shrub die-off, and other aspects of shrub biology and management; 1989 April 5-7; Las Vegas, NV. Gen. Tech. Rep. INT-276. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 1-7. Wright, H. A.; Nuenschwander, L. F.; Britton, C. M.1979. The role and use of fire in sagebrush and pinyon juniper plant communities: a state-of-the-art review. Gen. Tech. Rep. INT-58. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 48 p. Yensen, D. A. 1980. A grazing history of southwestern Idaho with emphasis on the Birds of Prey Study Area. Prog. Rep. Contract 52500-CT5-1002. Boise, ID: U.S. Department of the Interior, Bureau of Land Management. 82 p. Young, J. A.; Evans, R. A.; Major, J. 1972. Alien plants in the Great Basin. Journal of Range Management. 25: 194-201. Young, J. A.; Evans, R. A. 1978. Population dynamics after wildfires in sagebrush grasslands. Journal of Range Management. 31: 283-289. Young, James A.; Evans, Raymond A.; Eckert, Richard E., Jr.; Kay, Burgess L. 1987. Cheatgrass. Rangelands. 9(6): 266-270. 68