SPECIES: Achnatherum nelsonii



Zouhar, Kristin L. 2000. Achnatherum nelsonii. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/ [].




Stipa columbiana Macoun [10,25]
Stipa nelsonii Scribn. [23]
Stipa occidentalis Thurb. var. minor (Vasey) Hitchcoc. [22]
     = A. n. ssp. dorei [2]
Stipa columbiana var. nelsonii (Scribn.) St. John [10,54]




Columbia needlegrass
subalpine needlegrass
western needlegrass


The scientific name of Columbia needlegrass is Achnathrum nelsonii (Scribn.) Barkworth (Poaceae) [3,20,60]. Recognized subspecies are:

Achnathrum nelsonii ssp. dorei (Barkworth & J. Maze) Barkworth, Dore's needlegrass [3,20]   
Achnathrum nelsonii ssp. longiaristatum (Barkworth & J. R. Maze) Barkworth [3]
Achnathrum nelsonii ssp. nelsonii, Columbia or William's needlegrass [3,54]   




No special status




SPECIES: Achnatherum nelsonii

Columbia needlegrass grows throughout most of the West. It occurs from the Yukon and British Columbia east to western South Dakota, south to western Texas, Arizona, New Mexico and west to northern and eastern California, with the central Rocky Mountains as its center of distribution [10,53,21]. Dore's needlegrass (Achnatherum nelsonii ssp. dorei) does not occur in Nevada or Utah, and does occur in Texas [54]. Achnatherum nelsonii ssp. nelsonii is not found in Texas.


FRES20 Douglas-fir
FRES21 Ponderosa pine
FRES23 Fir-spruce
FRES29 Sagebrush
FRES35 Pinyon-juniper
FRES36 Mountain grasslands
FRES37 Mountain meadows
FRES38 Plains grasslands





4 Sierra Mountains
5 Columbia Plateau
6 Upper Basin and Range
7 Lower Basin and Range
8 Northern Rocky Mountains
9 Middle Rocky Mountains
10 Wyoming Basin
11 Southern Rocky Mountains
12 Colorado Plateau
13 Rocky Mountain Piedmont
15 Black Hills Uplift
16 Upper Missouri Basin and Broken Lands


K010 Ponderosa shrub forest
K011 Western ponderosa forest
K012 Douglas-fir forest
K015 Western spruce-fir forest
K017 Black Hills pine forest
K018 Pine-Douglas-fir forest
K019 Arizona pine forest
K020 Spruce-fir-Douglas-fir forest
K021 Southwestern spruce-fir forest
K023 Juniper-pinyon woodland
K024 Juniper steppe woodlands
K038 Great Basin sagebrush
K050 Fescue-wheatgrass
K051 Wheatgrass-bluegrass
K055 Sagebrush steppe
K056 Wheatgrass-needlegrass shrubsteppe
K063 Foothills prairie
K066 Wheatgrass-needlegrass


206 Engelmann spruce-subalpine fir
210 Interior Douglas-fir
217 Aspen
220 Rocky Mountain juniper
237 Interior ponderosa pine
238 Western juniper
239 Pinyon-juniper
256 California mixed subalpine


102 Idaho fescue
104 Antelope bitterbrush-bluebunch wheatgrass
105 Antelope bitterbrush-Idaho fescue
107 Western juniper/big sagebrush/bluebunch wheatgrass
108 Alpine Idaho fescue
109 Ponderosa pine shrubland
110 Ponderosa pine-grassland
216 Montane meadows
304 Idaho fescue-bluebunch wheatgrass
305 Idaho fescue-Richardson needlegrass
306 Idaho fescue-slender wheatgrass
312 Rough fescue-Idaho fescue
314 Big sagebrush-bluebunch wheatgrass
315 Big sagebrush-Idaho fescue
316 Big sagebrush-rough fescue
317 Bitterbrush-bluebunch wheatgrass
318 Bitterbrush-Idaho fescue
319 Bitterbrush-rough fescue
322 Curlleaf mountain-mahogany-bluebunch wheatgrass
401 Basin big sagebrush
402 Mountain big sagebrush
403 Wyoming big sagebrush
409 Tall forb
412 Juniper-pinyon woodland
421 Chokecherry-serviceberry-rose
504 Juniper-pinyon pine woodland
607 Wheatgrass-needlegrass
613 Fescue grassland


Columbia needlegrass is an indicator of climax in several sagebrush and pinyon-juniper habitat types. Publications listing Columbia needlegrass as an indicator or dominant species in habitat types are listed below:

Sagebrush-steppe habitat types in northern Colorado: a first approximation [15]
A habitat type classifcation of the pinyon-juniper woodlands of the Lincoln National Forest, New Mexico [26]
Forest and woodland habitat types (plant associations) of northern New Mexico and northern Arizona [28]
Plant associations (habitat types) of the forests and woodlands of Arizona and New Mexico [49]
Shrub-steppe habitat types of Middle Park, Colorado [50]

Columbia needlegrass commonly grows in association with lanceleaf rabbitbrush (Chrysothamnus viscidiflorus ssp. lanceolatus), spreading big rabbitbrush (Chrysothamnus linifolius), western yarrow (Achillea millefolium), and bluegrasses (Poa spp.) [53,55]. In north-central Colorado, Columbia needlegrass occurs as an understory dominant with Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) [15,50], and is also commonly associated with mountain big sagebrush (Artemisia tridentata ssp.vaseyana) and Idaho fescue (Festuca idahoensis) [50]. In the woodlands of New Mexico, Columbia needlegrass is a dominant understory plant occurring with Colorado pinyon (Pinus edulis) and oneseed juniper (Juniperus monosperma) [26,28,49].

In Wood Buffalo National Park, northern Alberta, Columbia needlegrass is considered a key species in the identification of dry grassland remnants in the Aspen parklands and boreal landscapes [43]. Here it is associated with rose (Rosa spp.), snowberry (Symphoricarpos spp.), northern bedstraw (Galium boreale), bearberry (Arctostaphylos uva-ursi), slender wheatgrass (Elymus trachycaulus), prairie Junegrass (Koeleria macrantha), quaking aspen (Populus tremuloides), Richardson needlegrass (Achnatherum richardsonii), and Virginia strawberry (Fragaria virginiana) [42]. Columbia needlegrass is also listed among the dominant species that are representative of "pristine vegetation" on a subalpine site in the Wasatch Plateau in Utah [13].


SPECIES: Achnatherum nelsonii

Columbia needlegrass provides valuable forage for many species of wildlife and all classes of livestock. Overall production is generally low in the upper sagebrush and mountain brush zones and at the limits of its range where Columbia needlegrass grows only in scattered patches [55,53]. It is usually more productive in open aspen and conifer sites, and in sub-alpine grasslands of the central Rocky Mountains, where it is especially valuable to cattle and horses on summer ranges [55] and to domestic sheep on lambing grounds [53]. It is more often cropped closely by cattle and horses than by sheep [53]. It has been found to make up a large portion of domestic sheep diets in the spring in a desert-forest fringe area of Oregon [56]. It is also consumed by mule deer [56,46] and other wildlife species throughout the growing season [55]. Needlegrasses are a significant component in the diet of pocket gophers [59].

Most needlegrasses cure well on the ground and can be used during the fall and winter [53]. The awns and/or callus of many species of needlegrasses can, however, cause injury to grazing animals. The pointed callus of Columbia needlegrass sometimes works into the mouths and ears of livestock [48]. Because of this, Columbia needlegrass is often avoided from the time of seed maturation until the ripe seed falls to the ground and can therefore withstand heavy grazing by domestic sheep in the central Rockies [55].


Columbia needlegrass is palatable to many species of wildlife and livestock throughout its range. As with most needlegrasses, it is most palatable early in the season before the foliage becomes coarse and wiry [53]. Palatability to cows and horses is increased because large amounts of fine leafage remain green throughout the gowing season [53,40]. Palatability of Columbia needlegrass is described as "fair to good" for cattle and horses, and "fair" for wildlife overall, becoming nearly unpalatable at maturity [48]. The degree of use by livestock and wildlife species for Columbia needlegrass in several western states is [12]:

                       CO       MT       ND       UT       WY
Cattle                Good     Good     Good     Good     Good
Sheep                 Fair     Fair     ----     Fair     Good
Horses                Good     Good     ----     Good     Good
Pronghorn             ----     ----     ----     Fair     Fair
Elk                   ----     ----     ----     Good     Good
Mule deer             ----     Good     ----     Fair     ----
White-tailed deer     ----     ----     ----     ----     Good
Small mammals         ----     ----     ----     Fair     Good
Small nongame birds   ----     ----     ----     Fair     Good
Upland game birds     ----     ----     ----     Fair     Good
Waterfowl             ----     ----     ----     Poor     Poor

Columbia needlegrass provides some cover for small birds and mammals. The degree to which Columbia needlegrass provides environmental protection during one or more seasons for wildife species is as follows [12]:

                      MT       UT       WY

Small mammals        Fair     Good     Good
Small nongame birds  Fair     Fair     Good
Upland game birds    Fair     Fair     Fair
Waterfowl            Good     Poor     Poor

Mc Arthur and others [30] suggest using Columbia needlegrass for reseeding disturbed meadow sites currently occupied by extensive stands of smooth brome (Bromus inermis) in Grand Teton National Park, Wyoming. Kay and others [24] note that the geniculate, twisted awn and sharp-pointed callus of Columbia needlegrass make harvesting and processing of seed difficult and planting next to impossible with conventional equipment. Seeds and planting guidelines are available through Davenport [11].


Most grazing animals avoid mature Columbia needlegrass because of its sharply pointed callus [48]. Consequently, Columbia needlegrass generally reproduces well in grazed areas, particularly where domestic sheep are present [40] and is listed as an increaser on some sites [31]. On severely overgrazed ranges Columbia needlegrass may be one of the last palatable species to disappear and one of the first to come back when range conditions improve [53]. For example, the dominance of Columbia needlegrass in subalpine rangelands of eastern Oregon and Washington is considered an indicator of past overgrazing [62]. This species increases on many ranges where bluegrasses (Poa spp.) and wheatgrasses (Triticeae) have been removed by overgrazing [18], and is considered a valuable replacement plant under these conditions [53].

Ellison [13] notes that Columbia needlegrass is unaffected by moderate grazing, but disappears under heavy grazing. Columbia needlegrass can be damaged when grazed during drought periods or when it grows as the most palatable species in scattered stands [55]. For example, in parts of the Southwest where it occurs with less palatable grasses, Columbia needlegrass is frequently grazed so closely that seeds cannot mature. Potter and Krenetsky [37] observed a greater increase in coverage of grasses, including Columbia needlegrass, in plots protected from grazing than in grazed plots in an upper ponderosa pine/Douglas-fir forest at 9400 ft (2870 m) in New Mexico. Leege and others [29] report that Columbia needlegrass consistently declines in abundance with grazing in the mountain meadows of north-central Idaho. Similarly, Columbia needlegrass was found only on undisturbed subalpine sites in a Wyoming study [52], and Rummell [39] found it present only on undisturbed sites in a ponderosa pine forest in central Washington.


SPECIES: Achnatherum nelsonii

Columbia needlegrass is a native, cool-season, perennial bunchgrass that grows in dense, leafy tufts [48]. It is long-lived and drought tolerant, with a slow to moderate seedling growth rate and medium herbage volume [19]. Culms are erect, 1-3.3 ft (0.3-1 m) tall, and stout. Leaves are narrow and mostly basal. Much of the foliage remains green throughout the growing season [53].

Panicles are 2.8-11.8 in (7-30 cm) long, narrow and dense, borne on short, appressed branches [48]. Spikelets are one-flowered, 0.2-0.3 in (5-7 mm) long; callus is pointed and sharp when mature; awns are 0.7-1.3 in (1.8-3.3 cm) long [48].

Roots are deep and fibrous, frequently extending vertically more than 3 feet (0.9 m) [45,53].




Columbia needlegrass reproduces by seed and by tillers [48]. Stubbendieck and others [48] provide the only mention of tillers in the literature. Tisdale and Hironaka [51] state that reproduction is entirely by seed in needlegrasses. Seed is typically produced in abundance and ripens during the late summer and early fall [40,51]. The sharp, pointed callus and awns aid in seed dispersal by ready attachhment to coats of animals [51]. Columbia needlegrass may regrow in the fall with adequate moisture [48]. Because of the sharp pointed callus, Columbia needlegrass is avoided from the time of seed maturation until the ripe seed falls to the ground. This morphological adaptation promotes stand replenishment [48].


Columbia needlegrass prefers well-drained, fine-textured soils with clay loam to sandy loam surface texture [19]. It has low fertility requirements and good heat tolerance, does well on shallow soils, is moderately tolerant of salinity, and can form a good ground cover on dry, rocky, infertile sites [19].

Columbia needlegrass grows on a wide variety of middle and upper elevation sites [21]. It occurs in dry plains, meadows and open woods in foothills and mountains [48] from the upper sagebrush zone to subalpine sites [53].

This species typically occurs as scattered individuals in uppermost elevations and moist sites of sagebrush [51] and mountain-brush zones [6], but is prominent in denser stands in the open parkland and drier sites of subalpine zones [55]. It also grows in extensive stands in the central Rockies but more often grows as scattered plants at the northern and southern edges of its range [53].

Columbia needlegrass is important at medium and high altitudes [21] and appears at the following elevations [25,40,50,28,55]:

Elevation in feet
AZ5,000-8,000 (1,640-2,440m)
CA7,000-10,000 (2,290-3,050m)
CO 7,000-8,030 (2,300-2,450m)
NM6,200-7,300 (1,890-2,225m)
UTabove 8,000 (2,440m)


Columbia needlegrass is a climax species in many sagebrush and pinyon-juniper communities [15,26,28,49,50]. It has also been found to be a successional species after fire in higher elevation vegetation zones in New Mexico, and has been observed in recently burned areas [26].


Columbia needlegrass begins growth in early spring. In sagebrush communities, seed ripens and disseminates in early and late July, respectively [51]. In the Sierra Nevada of California, seed generally ripens in August and September [40]. Foliage remains green throughout a long growing season and occasionally remains green until snow falls [53].


SPECIES: Achnatherum nelsonii

Perennial needlegrasses tend to be among the least fire resistant bunchgrasses [63,64] due, in part, to their densely tufted stems [66]. Columbia needlegrass is, however, only slightly to moderately damaged by fire [64], probably because it has relatively few culms per clump which may help to minimize the amount of subsurface heat transfer and subsequent damage.

The Colorado pinyon-oneseed juniper/Columbia needlegrass habitat type in the Lincoln National Forest of New Mexico may be maintained by relatively frequent, low-severity, surface fires [26]. Here Columbia needlegrass is not only a climax species, but it is also observed in areas with fairly recent burns.


Fire-return intervals for plant communities in which Columbia needlegrass occurs are summarized below. 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 in Years
basin big sagebrush Artemisia tridentata var. tridentata 12-43 [41]
mountain big sagebrush Artemisia tridentata var. vaseyana 5-15 [65]
Wyoming big sagebrush Artemisia tridentata var. wyomingensis 10-70 (40)** [65,57]
California montane chaparral Ceanothus and/or Arctostaphylos spp. 50-100 [8]
Rocky Mountain juniper Juniperus scopulorum < 35 [8]
pinyon-juniper Pinus-Juniperus spp. < 35 [8]
Colorado pinyon Pinus edulis 10-49 [8]
Rocky Mountain ponderosa pine* Pinus ponderosa var. scopulorum 2-10 [8]
quaking aspen (west of the Great Plains) Populus tremuloides 7-120 [8,32,17]
mountain grasslands Pseudoroegneria spicata 3-40 (10)** [1]
Rocky Mountain Douglas-fir* Pseudotsuga menziesii var. glauca 25-100 [8]
*Fire-return interval varies widely; trends in variation are noted in the Species review.


Tussock graminoid
Initial off-site colonizer (off-site, initial community)


SPECIES: Achnatherum nelsonii

Columbia needlegrass is generally top-killed by fire. In some instances, particularly with severe fires, soil heating caused by combustion of fine leaves at the soil surface further damages the plant. Researchers classify Columbia needlegrass as slightly to moderately damaged by fire [64].


Specific fire effects depend on the season of burn, phenology, plant size, and fire severity. Season of burn is of primary importance in determining the effects of fire on some needlegrasses [63]. The related species, needle-and-thread (Hesperostipa comata), which begins growth in the early spring, is most seriously injured by midsummer fires and less seriously damaged by late spring or fall burns [58]. Columbia needlegrass also begins growth during the early spring and a similar seasonal fire damage pattern is possible though not documented.

The effects of fire on bunch grasses are related to culm density, culm-leaf morphology, and size of the bunch. Densely clustered, leafy culms may burn long after passage of the flaming front [66]. Columbia needlegrass has relatively few culms per clump which may help to minimize the amount of subsurface heat transfer and subsequent damage. Wright and others [64] classify Columbia needlegrass and western needlegrass (Achnatherum occidentale) as slightly susceptible to damage by fire in sagebrush-bunchgrass communities, whereas needle-and-thread and Thurber needlegrass (Achnatherum thurberiana) are likely to be severely damaged by the fire. This difference appears to be related to the different amounts of dead material per unit basal area between species [7].

Large plants of needlegrass species are more susceptible to fire-caused damage than are smaller plants [64]. Basal area reduction has been noted in all size classes of needlegrasses, with large plants being most severely damaged [66]. With needlegrasses in general, plant size becomes an increasingly important determinant of fire damage late in the summer [63].


Columbia needlegrass is slightly to moderately damaged by fire [36] and has a moderate to rapid (2-10 years) postburn "recovery time" [66]. When the plant is only top-killed, regrowth can begin as early as the first post-burn season [67]. Increases in basal diameter [67], height [67], and dry weight production [33,5] have been recorded following burning. Because Columbia needlegrass does not spread by rootstocks and must await production of seeds, the number of individual plants increases slowly after burning [36].


The postfire response of Columbia needlegrass varies with season and intensity of burn, size of plants, and proximity to other fuels.

Fall prescribed burning seemed to stimulate seed production in Columbia needlegrass (number of seeds per plant) in a sagebrush (Artemisia spp.) grassland site [35]. Columbia needlegrasses had more inflorescences per plant and more florets per inflorescence contributing to greater seed production on plants in the 2-year-old burn than on adjacent unburned areas [35]. According to Mueggler and Blaisdell [33], an August prescribed burn to control big sagebrush appeared to benefit Columbia needlegrass in southern Idaho. Response following a variety of treatments was as follows:

Air-dry (lbs/acre) herbage production 3 years after treatment

  Untreated Control     August Burn      Sprayed   
          51                123            138       
Similarly, Blaisdell [5] found that Columbia needlegrass was not significantly affected by any intensity of burn 12 years after burning. The largest increases in dry weight occurred with moderate burning as opposed to light, heavy and unburned sites [5].

Aboveground tissues of a Columbia needlegrass plant with basal diameter 2 in (5 cm), observed at an August prescribed burn in a sagebrush/grassland in Nevada, was totally consumed by fire. One year later the plant had resprouted and by the 4th year after the burn, it was 160% of its original height. Researchers speculated that the removal of sagebrush may have helped this plant survive, though precipitation was below normal following the fire [67]. In the same area, four other Columbia needlegrass plants averaging 2 inches (5 cm) in basal diameter were observed before and after a prescribed burn in October of 1980. One of the 4 plants was growing in close proximity to snowberry and rabbitbrush. Three of the 4 plants resprouted in the 1st season after the burn, and by the 4th year had basal diameters of 20, 18, and 13 inches (8,7, and 5 cm). The plant surrounded by the highly flammable shrubs died [67].

In addition to Columbia needlegrass, 6 needlegrass plants including Thurber needlegrass and needle-and-thread grass were observed at the Horse Haven Two prescribed fire in a sagebrush-grass community in Nevada in October 1980. The effects of fire and subsequent plant responses to burning were not differentiated according to species. Needlegrass plants at this site averaged 3 inches (8 cm) in basal diameter and were growing in litter averaging less than 0.4 inch (1 cm) in depth. The fire spread was rapid and only defoliated the needlegrass plants. In some instances, 0.8 to 1 inch (2-3 cm) of stubble remained. Five of the 6 needlegrass plants resprouted 1 year after the fire. The 6th plant was undamaged and continued growing. Heights of the plants averaged 44% (of preburn height) in 1981, 34% in 1982, 91% in 1983, and 85% in 1984. The centers of several plants appeared dead, however. Damage was minimized by a lack of accumulated dead material in these relatively young and small-bunched needlegrass plants, and a lack of woody fuels or litter at the site [67].

Removal of competing sagebrush through prescribed burning may enhance survival of Columbia needlegrass, unless plants are in close proximity to shrubby fuels [67]. Abundant precipitation after fire may significantly aid recovery of Columbia needlegrass [67]. Pechanec [36] suggests waiting 10 days after seeds of perennial grasses are ripe and scattered before burning.


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