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grama (Bouteloua spp.)/sacahuista vegetation type 
open oak woodlands dominated by Mexican blue oak (Quercus oblongifolia) and Emory oak (Q. emoryi) 
oak (Quercus spp.)/sacahuista vegetation type 
encinal vegetation in the Santa Catalina Mountains 
Emory oak/pointleaf manzanita (Arctostaphylos pungens)-sacahuista vegetation on the Fort Bowie National Historic Site 
pygmy conifer-oak communities in the Santa Catalina Mountains with an overstory of Mexican pinyon (Pinus cembroides), alligator juniper (Juniperus deppeana), and/or silverleaf oak (Q. hypoleucoides) [50,80]
pine-oak woodlands dominated by ponderosa pine (P. ponderosa), Chihuahua pine (P. leiophylla var. chihuahuana), silverleaf oak, and/or Arizona white oak (Q. arizonica) in the Santa Catalina Mountains 
Mexican pinyon-Arizona white oak/sacahuista woodlands (USFS cited in )
shrub steppe in Peloncillo Mountains 
oneseed juniper (J. monosperma)/sacahuista-lechuguilla (Agave lechuguilla) in the Guadalupe and Sacramento mountains 
oneseed juniper-Colorado pinyon (P. edulis) woodlands in Fort Bayard 
western montane chaparral 
|© James L. Reveal, University of Maryland|
Some describe sacahuista as slow growing . During a long-term grazing study in central Arizona chaparral, 2 sacahuista plants, 1 inside and 1 outside an exclosure, were monitored periodically from 1920 to 1967. By 1967 both plants were dead, suggesting that the sacahuista life span may be less than 50 years .
This description provides characteristics that may be relevant to fire ecology, and is not meant for identification. Keys for identification are available (e.g., [25,41,55,76]).RAUNKIAER  LIFE FORM:
Pollination: Nolina (Nolina spp.) flowers are insect pollinated, likely by Hymenoptera and/or Diptera species .
Breeding system: Nolina plants are primarily dioecious, but perfect flowers may occur .
Seed dispersal: Fruit carpels are slightly inflated and likely easily dispersed by wind .
Seed production, seed banking, germination, and seedling establishment information was lacking as of the writing of this review (2007). The single mention of sacahuista seedlings came from an early postfire study where researchers did not locate sacahuista seedlings on 1- to 14-month-old burned sites in spite of an extensive search .
Vegetative regeneration: Sacahuista sprouts from the caudex following fire. Vegetative regeneration in the absence of other disturbance was not discussed in the available literature.SITE CHARACTERISTICS:
In southeastern Arizona [47,75] and on the Guadalupe Escarpment of New Mexico and Texas , sacahuista is typically most important on moderate to steep north-facing slopes. In a study of vegetation and terrain in southeastern Arizona, Mouat  found that sacahuista was predominant on steep slopes with angles averaging over 45%. Sacahuista was also associated with hilly and mountainous terrain with a high density of drainages (generally, >6 mi/mi²).
Climate: Semiarid climates are common in sacahuista habitats. Climate is variable in Arizona chaparral. Dry sites average 16 inches (400 mm) of annual precipitation, and wet sites average 26 inches (650 mm) of annual precipitation. However, extreme lows and highs can be 7.9 inches (200 mm) and 47 inches (1,200 mm) for the respective sites. Moisture occurs in a bimodal pattern. Approximately 55% of annual precipitation comes from November to April and 35% from July to September in convection storms . In western montane chaparral in Nuevo Leon, Mexico, the climate is cool semiarid. Average low and high temperatures are 52 °F (11 °C) and 62 °F (16.5 °C), respectively. Annual precipitation measures 30 to 39 inches (750-1,000 mm), and most comes from June to September .
Elevation: Sacahuista elevational tolerances by state or region are provided below:
|Mojave County||3,900 |
|southeastern Arizona||most common from 4,000-6,000 |
|New Mexico||4,000-8,000 |
|New Mexico and Texas (Guadalupe Escarpment)||most typical above 5,000 |
|Utah (Washington County)||3,900 |
Soils: Shallow, rocky, unfertile soils are described for sacahuista habitats [53,75]. In southeastern Arizona, sacahuista occurs primarily on nonalluvial parent materials . Emory oak/pointleaf manzanita-sacahuista vegetation on Fort Bowie National Historic Site occurs mainly on igneous or metamorphic rock substrates . Shrub steppe vegetation dominated by sacahuista in New Mexico's Peloncillo Mountains occurs on coarse loamy Cumulic Haplustoll soils . In the Santa Catalina Mountains of Arizona, sacahuista occurs on both limestone and noncalcareous soils . In central New Mexico, sacahuista occurred on a recent lava flow (<1,000 years old) but not on surrounding plains .SUCCESSIONAL STATUS:
Studies of succession in sacahuista habitats are generally lacking. However, some researchers have associated sacahuista habitats with disturbance. Southwestern desert grasslands, where sacahuista is often an associate, have been described as a "fire-caused subclimax" community [31,32]. The sacahuista-scrub oak (Q. turbinella) community is considered a "postclimax" type that results from heavy grazing and erosion in blue grama (Bouteloua gracilis) grasslands .SEASONAL DEVELOPMENT:
Fire regimes: Southwestern grasslands and woodlands that provide sacahuista habitat burned repeatedly in past centuries. Climatic conditions and fuel structure in these habitats are conducive to fire ignition and spread.
Research has shown that fire may affect sacahuista abundance, and that sacahuista may affect fire behavior and severity. Some researchers indicate that the range and density of sacahuista have increased on Arizona rangelands since 1900. Twenty percent or more kill of sacahuista after a fire in an oak-juniper woodland in the Santa Rita Mountains  suggests that fire restricts this slow growing species and that replacement of individuals would be slow if fires were recurring. See Discussion and Qualification of Plant Response for more on this study. Sacahuista's effect on fire behavior and severity was noted in the Chiricahua National Monument. Sacahuista reportedly "increases locally the fire intensity and flame height," and produces scorch and char heights that are "dramatically higher" on trees located above sacahuista plants .
Fire season: Fires in the Southwest are most common in late spring and early summer but are possible through the fall season. Lightning strikes occur from April to November but reach peak levels before the end of July. In National Forests of Arizona and New Mexico, 60% of the annual burned area burned in June lightning fires .
Fire frequency: Southwestern desert grasslands are thought to have burned repeatedly, and fire suppression efforts following European settlement are often associated with woody species increases and encroachment [31,32]. The fire frequency in Arizona grasslands before European settlement and heavy grazing in the area was estimated at 10 years , and Wright  indicates, in a review, that fires may have occurred at intervals of less than 10 years in southern New Mexico. Open oak woodlands in Santa Catalina Mountains dominated by Emory oak, Mexican blue oak, and alligator juniper easily carry fire, and woodland structure and composition are considered a result of fire and drought conditions .
Using newspaper reports of wildfires in southeastern Arizona, Bahre  summarized that fire size was greater from 1859 to 1890 than in the 1980s. From1859 to 1890, wildfires were fairly frequent and burned in all vegetation types. However, fires were twice as frequent in conifer forests and oak-juniper woodlands than in grasslands and 3 times as frequent in grasslands as in desert scrub communities. Occurrence of fires decreased after 1882 due in part to heavy grazing in the area that reduced fine fuels that carry fire .
Researchers determined the past fire regime for Chiricahua National Monument's Rhyolite Canyon from fire scars and living tree age structures. The canyon study area ranged from 5,381 to 7,313 feet (1,640-2,229 m). The mean fire-return interval for fires that burned most or all of the canyon was an estimated 14.6 years and ranged from 9 to 22 years for the 1655 to 1801 time period. After 1851, fires were recorded in the upper and middle portions of the canyon until 1886 when the last widespread fire was recorded. In the lower canyon, the fire-return interval decreased to 6 years from 1852 to 1924 .
The following table provides fire-return intervals for plant communities and ecosystems where sacahuista is important. Find fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find Fire Regimes".
|Community or Ecosystem||Dominant Species||Fire-Return Interval Range (years)|
|desert grasslands||Bouteloua eriopoda and/or Pleuraphis mutica||<35 to <100 |
|plains grasslands||Bouteloua spp.||<35 [51,82]|
|blue grama-needle-and-thread grass-western wheatgrass||Bouteloua gracilis-Hesperostipa comata-Pascopyrum smithii||<35 [51,59,82]|
|blue grama-buffalo grass||Bouteloua gracilis-Buchloe dactyloides||<35 [51,82]|
|grama-galleta steppe||Bouteloua gracilis-Pleuraphis jamesii||<35 to <100 |
|cheatgrass||Bromus tectorum||<10 [52,77]|
|paloverde-cactus shrub||Cercidium spp./Opuntia spp.||<35 to <100|
|pinyon-juniper||Pinus-Juniperus spp.||<35 |
|Mexican pinyon||Pinus cembroides||20-70 [46,68]|
|Colorado pinyon||Pinus edulis||10-400+ [26,29,37,51]|
|interior ponderosa pine*||Pinus ponderosa var. scopulorum||2-30 [3,5,39]|
|Arizona pine||Pinus ponderosa var. arizonica||2-15 [5,18,61]|
|oak-juniper woodland (Southwest)||Quercus-Juniperus spp.||<35 to <200 |
Sacahuista density was not changed significantly 2 years following a spring fire in the Malpai Borderlands. Sacahuista was top-killed and sprouted after the fire, but fire severity was not reported . Sacahuista decreased after a fire above the Molino Basin in Arizona's Santa Catalina Mountains. Neither fire characteristics nor sacahuista abundance comparisons were provided . Density of sacahuista was typically lower on burned than unburned sites in the 1st and 2nd years following a late June wildfire near Sasabe, Arizona, and density decreased on northern slopes between the 1st and 2nd postfire growing seasons. Fire severity was not reported .
After a late June fire in a Madrean oak woodland in the Santa Catalina Mountains, sacahuista coverage decreased. Fire severity was not reported. Burned plots, stratified by aspect, were visited 10 months and 2.5 years after the fire. Southern, eastern, and northern aspects were described as "very open, open, and relatively" dense woodlands, respectively. Canopy dominants were Emory oak and Mexican blue oak, and there was no evidence of recent fire in the study area. Sacahuista recovered to unburned coverage by 2.5 years after the fire on southern but not on eastern or northern slopes. Few sacahuista plants died, and the frequency of sacahuista on pooled burned and unburned plots was not different. Plants sprouted quickly from the outer edges of the caudex. Researchers noted that plants were very leafy on unburned sites and measured the largest fuel load when sacahuista fell within the 10-foot² (1 m²) quadrat. Meristem protection at or below the soil surface likely affected survival. Sacahuista coverage on burned and unburned plots is summarized below [13,14]:
|Time since fire||10 months||2.5 years|
Sacahuista numbers and "vigor" had declined 2 years after fire on sites burned in mid-June in an oak-juniper woodland in the Box Canyon of the Santa Rita Mountains. Fire characteristics were not reported. On burned sites, 10% of sacahuista plants were dead, 10% were producing a few weak sprouts but dying back, and 15% produced sprouts but were in a "weakened" condition. Researchers doubted the survival of all "weakened" plants. Fifty-two percent of sacahuista plants had slight damage but were not as "vigorous" as unburned plants, and 13% had recovered to the unburned condition .
Survival of sacahuista was better than in the above study on 2 burned semidesert grassland sites in southern Arizona. Burned areas within the Buenos Aires National Wildlife Refuge and in the Dry Canyon of the Whetstone Mountains were studied 1 to 14 months after burning. Survival was evaluated using unburned reference sites as a measure of the prefire condition. Fuel loads were 435 g/m² in the Buenos Aires National Wildlife Refuge and 179 g/m² in the Dry Canyon. Fire season and severity were not described. Sacahuista mortality was 4%. Ninety-six percent of surviving sacahuista recovered through sprout production, and 4% escaped the fire in unburned refugia. Although extensive searches for seedlings on burned sites were conducted, researchers found no sacahuista seedlings .FIRE MANAGEMENT CONSIDERATIONS:
Fuel moisture: The average moisture content was 110% and ranged from 101% to 117% for 4 sacahuista samples collected from the Chiricahua National Monument in November .
In chaparral vegetation in central Arizona's Sierra Ancha Experimental Forest, 2 sacahuista plants, 1 outside and the other inside the exclosure, were marked and evaluated 7 years later. The plant outside the exclosure was closely browsed, but the grazing animal was not identified .
Livestock: Sacahuista is rarely browsed by domestic livestock. Some indicate that sacahuista leaves are browsed in times of drought and/or when other forage is unavailable [33,36]. Sacahuista stands that are heavily browsed are an indication that stocking rates are too high [22,33].
Sacahuista buds, blooms, and seeds are toxic to domestic sheep . Cattle are considered less susceptible to poisoning. In Agua Prieta, Sonora, sacahuista leaves that remain after processing plants for use in brooms are fed to local cattle. In this area ranchers encourage sacahuista harvesting on their land, as it encourages new growth that is palatable to cattle .
Deer: Southwestern mule and white-tailed deer utilize sacahuista and sacahuista habitats. In the San Cayetano and Dos Cabezas mountains of southeastern Arizona, researchers found that sacahuista was important in the diets and habitats of white-tailed and mule deer. Regardless of season and climatic conditions, sacahuista was ranked 7th in the 7 most important mule and white-tailed deer foods in the area. Consumption of sacahuista flower stalks increased in a drought year [1,2].
Sacahuista sprouts and buds averaged 6% of the volume of 11 mule deer stomachs analyzed in late spring in south-central Arizona's Three Bar Wildlife Area. The greatest volume of sacahuista per sample was 32%. Sacahuista was not recovered from white-tailed deer stomachs or from either species in any other season. Sacahuista frequency ranged from 0 to 30% in the chaparral and desert zones of the study area. Researchers found that sacahuista leaves in the late spring had protein levels of just 4% [42,73].
Small mammals: In paloverde-prickly-pear (Cercidium-Opuntia spp.) vegetation in the Sugarloaf Mountain area of Arizona's Maricopa County, stomachs of 96 desert cottontails were analyzed. Sacahuista occurred with an average frequency of 10.3% in stomachs collected between March 1972 and June 1973 .
Birds: Sacahuista is important in quail and wild turkey habitats. Sacahuista was a dominant species in Montezuma quail habitats in the eastern foothills in the Santa Rita Mountains and Canelo Hills southeast of Tucson. However, sacahuista was not recovered from crops . The Emory oak-sacahuista-sideoats grama (Bouteloua curtipendula) habitat in the Peloncillo Mountains of New Mexico's Hidalgo County received use proportional to its availability by wild turkeys in the winter. Use was low in the spring, and 1 of 10 summer telemetry observations were made in this habitat .
Palatability/nutritional value: Dry weight composition of sacahuista collected in Arizona was 3.1% ash, 4.7% crude protein, 45% crude fiber, 2.2% fat, and 45% nitrogen-free extract . Sacahuista leaves collected from Arizona chaparral in early May were 4% crude protein, 55% acid detergent fiber, 0.62% calcium, 0.16% phosphorus, and 26% invitro digestibility .
Cover value: Sacahuista is important in a variety of wildlife habitats and likely provides important cover for small mammal and bird species.VALUE FOR REHABILITATION OF DISTURBED SITES:
Sacahuista is still used today in weaving and in broom head construction . Sacahuista is harvested by machete, taken to processing plants, and made into broom heads. Harvesting previously harvested stands is typically quicker and more fruitful, as there are fewer dead leaves and irregular-sized leaves. Ranchers typically encourage sacahuista harvesting on their land because new growth is considered more palatable. Harvesting sacahuista may also improve quail habitat and deer browse by removing dead plant material (Fitch, personal communication in ). Harvesting is illegal in some areas .OTHER MANAGEMENT CONSIDERATIONS:
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