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Salix amygdaloides

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Fryer, Janet L. 2012. Salix amygdaloides. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: [].


peachleaf willow
peach-leaf willow
peach leaf willow

The scientific name of peachleaf willow is Salix amygdaloides Anderss. (Salicaceae) [9,16,33,36,74,78,81,83,114,145]. It is in the black willow section (Humboldtiana) of Salix [7,9].

Peachleaf willow hybridizes with other Humboldtiana willows [86], including coastal plain willow (S. caroliniana) [7,81], black willow (S. nigra) [33,81], and Goodding's willow (S. gooddingii) [33]. Peachleaf willow hybrids include:

Salix × glatfelteri C.K. Schneid. (× S. nigra), Glatfelter's willow [7,33,36,81,83]; occurs in the Midwest [141]
× wrightii Andserss. (× S. gooddingii), Wright's willow; occurs in Arizona, New Mexico, and Texas [33,56].
       Synonym: Salix amygdaloides var. wrightii (Anderss.) Schneid. [80]

Salix nigra var. amygdaloides (Anderss.) Anderss. [8]



SPECIES: Salix amygdaloides
Map courtesy of USDA, NRCS. 2012. The PLANTS Database. National Plant Data Team, Greensboro, NC. (2012, June 21).

Peachleaf willow is native to North America. It is the most common tree willow in the eastern Great Plains [47], but it is peripheral in the Southeast, occurring mostly in the Mississippi valley [7]. In the Southwest, it is common along the Rio Grande [102] and rare to infrequent in other riparian zones [67]. Its distribution extends south into Chihuahua [81]. It rare in Quebec, Ontario, and British Columbia and has been extirpated from Kentucky [78].

States and provinces:
United States: AZ, CO, IA, ID, IL, IN, KS, KY, MI, MN, MO, MT, ND, NE, NM, NV, NY, OH, OK, OR, PA, SD, TX, UT, WA, WI, WY
Canada: AB, BC, MB, ON, QC, SK [141]
Mexico [16,31,81]

Site characteristics:
Moisture regime: Peachleaf willow is restricted to moist sites [7]. Modeling indicated peachleaf willow importance value was highest on sites averaging around 19.7 inches (500 mm) of annual precipitation and 41 °F (5 °C), with a tolerance range of 9.8 to 48.2 inches (250-1,225 mm) of precipitation and 36 to 55 °F (2-13 °C). A high water table was the most important predictor of peachleaf willow presence, followed by spodosol or histosol soils. Elevation was among the least important factors [103]. Peachleaf willow grows on moist to mesic floodplains, lakeshores, near streams and rivers, and in marshes, swamps, sloughs, seeps, and moist gullies across its range [7,25,33,36,39,51,63,83,103,147]. It tolerates poor drainage and prolonged flooding [43]. On the Lower Platte River of eastern Nebraska, vegetation surveyors found peachleaf willow only in moist, bottomland plains cottonwood (Populus deltoides subsp. monilifera) forests. They did not find it in drier communities including transitional, riparian-upland bur oak-American basswood (Quercus macrocarpa-Tilia americana) and upland mixed-oak (Quercus spp.) forests [111]. On the banks of the Canadian River in the Texas panhandle, peachleaf willow was noted only in bottomlands with plains cottonwood [112]. During the Dust Bowl drought in the late 1930s, 75% to 100% mortality was noted for peachleaf willow and other woody riparian species in south-central South Dakota. Most trees near streams with permanent water tables survived, however [137].

Soils: Peachleaf willow grows in sands, silts, and gravels [7,33,59] that are typically low in organic matter [59]. Hansen and others [43] noted that in eastern Montana, peachleaf willow grew in soils of all textures except heavy clays. Silts and sands were most common. Peachleaf willow tolerated weakly saline soils [43]. However, the US Natural Resources Conservation Service [141] lists peachleaf willow as saline intolerant. It has a pH tolerance from 6.0 to 8.0 [141]; in Montana, it tolerates mildly alkaline soils [43].

Peachleaf willow is especially common on new pointbars (alluvium on the inside of river curves) of sand or gravel [94]. On the Knife River Indian Villages National Historic Site, North Dakota, peachleaf willow occurred on young surfaces formed by river action: pointbars, islands, shore deposits, and abandoned channels. These features were prominent on the confluence of the Knife and Missouri rivers. In plains cottonwood/peachleaf willow communities near the confluence, tree density averaged 335 trees/ha, with 74% plains cottonwoods, 24% peachleaf willow, and 2% Russian-olive (Elaeagnus angustifolia) [17]. Peachleaf willow was noted on sandbars and islands on the Platte River of south-central Nebraska [95]. It is also found in deep, very poorly drained peats and mucks in the Great Plains. These sites are permanently flooded and usually dominated by common buttonbush (Cephalanthus occidentalis) [77]. In Wisconsin's Point Beach State Forest, peachleaf willow grows on foredunes, interdunes, strands, sand ridges, and sand blowouts on the shores of Lake Michigan [143].

Parent materials of soils with peachleaf willow are varied. In Wyoming, peachleaf willow grows in soils derived from shale, sandstone, marlstone, and granite [97].

Elevation: Elevation is apparently less limiting than moisture for peachleaf willow [103]. It is noted in "wet low places" in the Northeast [36] and in moist subalpine [133] and alpine [23] sites in the Southwest. In the East, elevational ranges of peachleaf willow were not described in the literature (as of 2012). In the West, peachleaf willow occurs from low to high elevations:

Elevational ranges for peachleaf willow in the western United States
Area Range (feet)
Arizona ≤7,000 [67]
Colorado 3,500-7,500 [47,68]
New Mexico 4,500-7,400 [16]
Nevada 4,500-6,000 [63]
Texas 2,900-4,500 [102,120]
Utah 3,510-5,610 [147]
Northern Rocky Mountains 1,500-7,700 [25]
Southwest 3,000-7,000 [8]

Plant communities: Peachleaf willow is restricted to riparian, wetland, and woody draw communities throughout its range. Most commonly, it is associated with cottonwoods (Populus spp.) and other willows (Salix spp.). See the Fire Regime Table for a list of plant communities in which peachleaf willow may occur and information on the fire regimes associated with those communities. Detailed descriptions of plant communities where peachleaf willow is important or dominant are provided below by region.

Great Lakes: In south-central and southeastern Canada and the Great Lakes states, peachleaf willow occurs in hardwood, conifer, and mixed riparian ecosystems, including elm-ash-cottonwood (Ulmus-Fraxinus-Populus spp.) [94], white pine-jack pine (Pinus strobus-P. banksiana), quaking aspen-paper birch (Populus tremuloides-Betula papyrifera), mixed pine-aspen (Pinus-Populus spp.) [93], and mixed-hardwood [21] forests. It also occurs in willow (Salix spp.) shrublands and occasionally in wet meadows. Generally, peachleaf willow occurs in plant communities adjacent to watercourses that are in early successional stages. In southern Manitoba, peachleaf willow codominates with green ash (F. pennsylvanica), shining willow (S. lucida), and sandbar willow (S. interior) in the flood zone of Lake Manitoba. Creeping bentgrass (Agrostis palustris), reed grass (Phragmites communis), and bluejoint reedgrass (Calamagrostis canadensis) occur in the ground layer. It also grows in terrace communities with plains cottonwood, boxelder (Acer negundo), and black willow (S. nigra) [82]. By the Montreal River in Quebec, peachleaf willow codominates on shorelines of sandy alluvium with black willow, meadow willow (S. petiolaris), Missouri River willow (S. rigida), and/or common buttonbush. Reed canarygrass (Phalaris arundinacea), bluejoint reedgrass, and/or nonnative purple loosestrife (Lythrum salicaria) dominate the herbaceous layer. Sugar maple (Acer saccharum) dominates on shorelines of sandy loam [144]. Peachleaf willow was a minor species in red maple-American elm-black cottonwood (Acer rubrum-U. americana-Populus balsamifera subsp. trichocarpa) wet forests of Wisconsin [21], and it was relatively uncommon (3.9% frequency) in shrub mires of southeastern Wisconsin. The mires were poorly drained; meadow willow was most frequently dominant [148]. In northern Michigan, peachleaf willow occurred on a newly exposed lake bottom with Bebb willow (S. bebbiana), sandbar willow (S. longifolia), shining willow, red-osier dogwood (Cornus stolonifera), and roundleaf dogwood (C. rugosa). Broad-leaved cattail (Typha latifolia), bulblet-bearing water-hemlock (Cicuta bulbifera), and other hydrophytic herbs were also present. The upland community was a white pine-jack pine-quaking aspen forest [93]. In southeastern Wisconsin, peachleaf willow occurs in and on the edges of tussock sedge (Carex stricta) wet meadows [18].

Northern and Central Rocky Mountains: In riparian areas of the Rocky Mountains, peachleaf willow often dominates shrublands on sand- and gravelbars, and it is common to dominant in the understories of plains cottonwood and green ash forests [12]. Bulrushes (Scirpus spp., sensu latu), broad-leaved cattail, and giant goldenrod (Solidago gigantea) are typical groundlayer species [54]. In Wyoming, peachleaf willow is a minor to codominant species in moist shrublands dominated by Woods' rose (Rosa woodsii) or prickly rose (R. acicularis subsp. sayi) [97]. Peachleaf willow community types occur along the Missouri [45], Yellowstone [12], Milk, and other rivers of Montana. Herbs, including fowl bluegrass (Poa palustris), reed canarygrass, and wild licorice (Glycyrrhiza lepidota), dominate the ground layer. These peachleaf willow shrublands are uncommon in Montana [45]. Along the Milk River of northwestern Montana, plains cottonwood/sandbar willow- peachleaf willow gallery forests occurred in discontinuous strips on moist pointbars and other sites of channel deposition; the willows also grew on channel levees. Silver sagebrush (Artemisia cana), western wheatgrass (Pascopyrum smithii), and needle-and-thread grass (Hesperostipa comata) occupied dry stretches on upper terraces of the riverbank [98]. A mixed peachleaf willow-narrowleaf willow-Pacific willow (S. exigua-S. lasiandra) riparian association is noted in Idaho [57]. Surveys of BLM riparian sites in Idaho revealed that peachleaf willow habitat types were incidental in south-central and eastern portions of the state, occurring at low elevations (4,100-4,900 feet (1,242-1,484 m)) along oxbows, islands, floodplains, and lake or pond margins. Stands were often closed, with a sparse herbaceous layer. However, peachleaf willow was common in several cottonwood habitat types, including black cottonwood/red-osier dogwood and narrowleaf cottonwood (P. angustifolia)-black cottonwood/red-osier dogwood [44]. Peachleaf willow-Pacific willow and peachleaf willow-Russian-olive communities occur along the Snake River [14]. Along a 52-mile (83 km) stretch of the Snake River near the Idaho-Oregon border, peachleaf willow codominated riparian woodlands with sandbar willow, nonnative Russian-olive, and/or nonnnative saltcedar (Tamarix ramosissima). Two-thirds of tree basal area and density in these riparian communities was composed of the 2 nonnative species [24].

In the Roosevelt National Forest of western Colorado, peachleaf willow codominated a mixed-willow community with planeleaf willow (S. planifolia), Geyer willow (S. geyeriana), and narrowleaf willow. Sedges (Carex spp.), Kentucky bluegrass (Poa pratensis), and tufted hairgrass (Deschampsia cespitosa) dominated the ground layer. Soils were sandy loams or clay loams above a shallow water table. They were saturated during most of the growing season, and the water table was <9.8 feet (3.0 m) below ground in summer [53]. Surveys done in the early 1980s on floodplains of the South Platte and Arkansas rivers found plains cottonwood, peachleaf willow, saltcedar (T. chinensis), and sandbar willow usually dominated the overstory. Peachleaf willow was most frequent in plains cottonwood communities [79].

Peachleaf willow may occur in the shrub layer of mesic conifer forests. It is common in the understories of Engelmann spruce-Rocky mountain lodgepole pine-subalpine fir (Picea engelmannii-Pinus contorta var. latifolia-Abies lasiocarpa) forests of Wyoming; these forests occur from 6,500 to 9,000 feet (2,000-3,000 m) elevation [97].

Great Plains: The cottonwood-willow (Populus-Salix spp.) cover type dominates many floodplains and other riparian areas across the Great Plains; peachleaf willow and/or black willow typically codominate the canopy layer with various cottonwoods [106,113]. Even when it is not dominant, peachleaf willow is considered characteristic of cottonwood-willow vegetation types of the Great Plains [72]. Plains cottonwood-willow galleries occur in a narrow zone adjacent to rivers and streams. Upland vegetation is typically a mix of short and tall grasses, with sharp boundaries between the galleries and grasslands [61].

Throughout the Great Plains and Great Basin, peachleaf willow is an occasional, scattered tree in common three-square bulrush (Schoenoplectus pungens) wet meadows. Cosmopolitan bulrush (S. maritimus) and Baltic rush (Juncus balticus) are also common in this association; eastern cottonwood (Populus deltoides) or Fremont cottonwood (P. fremontii) may also occur as scattered individuals [100].

Northern Great Plains: A peachleaf willow tall-shrub community type is described for southeastern Alberta [135] and southern Saskatchewan [134]. It occurs in narrow bands within the plains grasslands in meander and overflow channels, on pond and lake margins, and in backwaters and woody draws. Western wheatgrass and fowl bluegrass dominate the herb layer; yellow willow (S. lutea) and red-osier dogwood may codominate the overstory [134,135]. On the Minnesota River of North Dakota, peachleaf willow formed distinct thickets along parts of the riverbank. Sandbar willow also formed thickets along the riverbank. Just upland, the mature floodplain forest was dominated by silver maple (Acer saccharinum), American elm, green ash, and boxelder [94]. Hansen and others [43] reported a minor peachleaf willow community type along streams, rivers, lakes, and ponds of eastern Montana. Peachleaf willow usually assumed a multistemmed shrub form, with stands averaging 50 to 75 years old [43]. In the Black Hills National Forest, South Dakota, peachleaf willow grows in bur oak/western snowberry (Symphoricarpos occidentalis) associations from 3,500 to 4,200 feet (1,100-1,300 m) elevation; these associations occur in glaciated areas along intermittent streams [60].

A study that compiled data from sites across the Northern Great Plains reported that old-growth plains cottonwood-green ash-peachleaf willow gallery forests supported 77 to 482 trees/acre [69].

Peachleaf willow is a component of some prairie pothole communities in the Northern Great Plains. Along with other woody plants including eastern cottonwood, sandbar willow, and Russian-olive, it spread into potholes in the first half of the 20th century. This invasion may be due to fire exclusion [69].

Central and Southern Great Plains: Peachleaf willow is prominent in woody draws and galleries of this region. It may be the only tall woody species on the plains grasslands of eastern Colorado [68], although it often cooccurs with cottonwoods in riparian zones. In gallery forests, peachleaf willow often codominates with plains cottonwood. Big bluestem (Andropogon gerardii), indiangrass (Sorghastrum nutans), and/or sideoats grama (B. curtipendula) dominate the ground layer [64]. Kuchler [73] reported peachleaf willow as dominant in floodplain forests and savannas of Kansas, with plains cottonwood codominant in western Kansas and eastern cottonwood (P. deltoides subsp. deltoides) and American elm codominant in eastern Kansas. On floodplains of the Republican River, plains cottonwood-peachleaf willow-black willow communities establish on alluvial strands, while bluestem-grama (Andropogon-Bouteloua spp.) plains grasslands occur upland [11]. On the Arkansas River and other major rivers and streams, eastern cottonwood-peachleaf willow/narrowleaf willow alliances occur on nearly-level floodplains of recent alluvium [77]. In the mid-1850s, land surveyors in Republic County, Kansas, found peachleaf willow occurred in diverse, mixed-deciduous communities with plains cottonwood, eastern cottonwood, common hackberry (Celtis occidentalis), black walnut (Juglans nigra), and bur oak. These communities were found along streams within black grama (B. gracilis)-sideoats grama plains grasslands [85]. In the Nebraska sandhills, peachleaf willow cooccurs with eastern cottonwood in wet areas [96].

On the Arikaree and South Fork Republican rivers of eastern Colorado, a plains cottonwood overstory established after the record flood of 1935. By of the turn of the 21st century, no further plains cottonwood establishment was recorded. In the subcanopy, however, there were single-stemmed peachleaf willow trees dating back to the 1935 flood, plus multistemmed peachleaf willow shrubs that had sprouted from the bases of older stems. Shrub forms tended to grow near active channels and/or were associated with heavy mule deer browsing. Russian-olive codominated the subcanopy. All Russian-olives had established since the 1950s, when flood control measures (such as damming) were initiated [65].

An 1885 survey near El Paso, Texas, found that timbered stands along the Rio Grande were primarily confined to river bottoms. Plains cottonwood, peachleaf willow, and black willow codominated these stands [49].

Southwest: Peachleaf willow occurs in riparian zones and washes in the Southwest and Mexico [16]. Peachleaf willow was important in the canopy layer of thinleaf alder (Alnus incana subsp. tenuifolia)-mixed deciduous riparian communities of Arizona and New Mexico. Fremont cottonwood and boxelder were often codominant [133]. In Canyon de Chelley National Monument, Arizona, Rio Grande cottonwood (P. deltoides subsp. wislizeni)/peachleaf willow-Russian-olive communities occurred on canyon bottoms below 6,000 feet (2,000 m). Groundlayer vegetation was a mix of herbs including native sedges (Carex spp.) and witchgrass (Panicum capillare) and nonnative grasses including Kentucky bluegrass and tall fescue (Schedonorus arundinaceus). Russian-olive was planted in 1964 and was spreading upslope by 1976, but Gambel oak (Q. gambelii) and boxelder still dominated the upland communities [46]. In New Mexico, peachleaf willow codominates with Goodding willow, Fremont cottonwood [23], and/or Rio Grande cottonwood [55]. It dominates a minor willow vegetation type [23]. By the Rio Grande in central New Mexico, peachleaf willow and Goodding willow codominate the subcanopy of Rio Grande cottonwood galleries. Narrowleaf willow, saltcedar (T. chinensis), Russian-olive, and stretchberry (Forestiera pubescens) occur in the shrub layer [55]. A Rio Grande cottonwood-peachleaf willow community type also occurs along the Pecos River [90]. Peachleaf willow dominates some alpine riparian zones of New Mexico; Bebb willow and bluestem willow (Salix irrorata) are common codominants. These riparian communities usually run through alpine meadows [23].


SPECIES: Salix amygdaloides
Botanical description: This description covers characteristics that may be relevant to fire ecology and is not meant for identification. Keys for identification are available (for example, [7,8,25,36,51,63]).

Peachleaf willow is a deciduous small tree or shrub ≤40 feet (12 m) tall [74]. It grows as a small tree in most of its range [16,31,39,63,67,147], although the shrub form is more common in Montana [74]. It is the tallest native willow in the prairie states [39] and provinces [31]. As a tree, its form is spreading [80] and often leaning [36,125] to decumbent [44]. As a shrub, peachleaf willow often forms thickets [94,146]. Trunks may be one to several [51] and reach 1.3 feet (0.4 m) across [36,80]. The wood is soft and weak [125]. Branches are flexible throughout most of their length but may be brittle at the base [33]. Leaves are lance-shaped; typically, they range from 0.8 to 2 inches (2-6 cm) long [36,147], but they may be 4 to 6 inches (11-16 cm) on young shoots [38,47,147]. The male and female flowers are catkins [16,33,36,74]. Female catkins are 2 to 3 inches (5-8 cm) long, arising from leafy twigs [80]. The fruit is a capsule [16,33,39,80] containing many small seeds with cottony hairs [80]. The seeds are lightweight; near Boulder, Colorado, peachleaf willow seeds averaged 4.0 × 10-5 g each [127].

Peachleaf willow has a multibranched, spreading root system [89,124]. Comparing the root systems of woody riparian species in eastern Nebraska, researchers reported that peachleaf willow "probably exceeds all other species in rate of root penetration". Depth to water table probably determines root depths. In silt loams in Lancaster County, roots of a 4-year-old peachleaf willow spread 14 feet (4.3 m) deep and 12 feet (3.7 m) wide; the water table was at 16 feet (4.9 m). On another site with sandy loam, a 48-foot (15 m) peachleaf willow had roots only 2.5 feet (0.8 m) deep but 44 feet (13 m) wide; the water table was 2.5 feet below ground [124].

A fact sheet describes peachleaf willow as short-lived [141].

Raunkiaer [105] life form:

Peachleaf willow flowers, fruits, and disperses seed in spring [141,141]. Catkins and leaves emerge at the same time [25,39]. Seed dispersal usually coincides with spring flooding [20]. In Canyon de Chelly National Monument, peachleaf willow seedfall peaked in May and June [107]. Near Boulder, Colorado, seedfall peaked during the last 2 weeks of May [127]. In Fort Collins, Colorado, seed dispersal dates across 3 years (1994-1996) varied by 3 weeks (31 May- 23 June). Delayed seed production in 1995 was attributed to below-normal temperatures and frequent rains in May and early June [109]. Peachleaf willow flowers from early April to June to across its range [33]:

Peachleaf willow phenology
Area Event
Minnesota flowers May-June [151]
Nevada flowers May-June [63]
North Dakota flowers May [128]
Wisconsin flowers April-mid-May [7]
Great Plains flowers May
fruits late May-June [39,125]

Peachleaf willow regenerates from seed and vegetatively. Both methods are important to its fecundity.

Pollination and breeding system: Peachleaf willow is mostly dioecious [66,151], although flowers are occasionally perfect [32]. In Nebraska, ratios of male:female plants averaged 1:1 [66].

Although peachleaf willow hybridizes, greenhouse studies suggest that different periods of pollen release among willows [88] and low fertility of hybrids [87] may limit hybridization and formation of hybrid peachleaf willow swarms. In the greenhouse, female peachleaf willow flowers were receptive to pollination for 4 days; that was the longest period of receptivity among 6 willow species [86].

Seed production: Peachleaf willow plants produce thousands of very small seeds [141]. Because peachleaf willow and other willows are preferred browse species, moose and other browsing herbivores may reduce seed production considerably [151].

Sprouts generally produce seed at a younger stem age than plants derived from seeds [151].

Seed dispersal: Wind and water disperse peachleaf willow seeds [20,150,151]. The cottony hairs aid in dispersal [151]. Wind may carry the seeds long distances, although most land near the parent plant [151]. In the South Platte River Watershed in north-central Colorado, willow seed rain collected in aerial traps averaged 524 seeds/m³/week; seeds dispersed in mid-July. Peachleaf willow was among 5 willows that occurred on study sites; the willow seeds were not identifiable to species [84]. In Canyon de Chelly National Monument, aerial seed rain of peachleaf willow and 3 other willow species peaked at 213 seeds/m²/day. Seeds were trapped on sticky plywood in May and June [107].

Cottony peachleaf willow seeds. Photo by Dave Powell, USDA Forest Service,

Seed banking: The seeds of peachleaf willow and other willow species are short-lived, so seed banking does not occur in willows. Willow species that disperse seed in spring [151], such as peachleaf willow 142, lose seed viability even more rapidly than willows that disperse seed in fall [151]. At best, fresh peachleaf willow seeds are viable for a few days. Even under ideal storage conditions, the seeds are viable for only 4 to 6 weeks [141].

Germination: Willow seeds generally germinate within 12 to 24 hours of dispersal onto moist substrates [141,150]. Other than needing moisture, little was known of the germination requirements of willows in general [150] and peachleaf willow in particular as of 2012.

Seedling establishment: Peachleaf willow establishes on pointbars, mudflats, and other newly deposited or newly exposed, moist surfaces [58,110]. Meandering rivers tend to have many sites that favor peachleaf willow establishment [58]. In small streams, scouring activity may not be strong enough to create substrates favorable for peachleaf willow seedling establishment. In the plains grasslands of northwestern Nebraska, mature peachleaf willows grew only intermittently along small streams, and no seedlings were found. However, peachleaf willow was common to dominant and represented in all age classes along larger waterways that experienced heavy bank scouring [139].

The substrate must be continuously moist for peachleaf willow germinants to survive [20]. Establishment is mostly confined to the pioneer stage of riparian succession [20,58]. Mineral soil or gravel is the typical substrate, although establishment also occurs on other moist substrates. Seeds must be on the substrate surface; buried seeds show low rates of emergence [151]. In eastern Colorado, peachleaf willow showed best establishment in channel narrows and other areas where scouring occurred [65] (see Vegetative regeneration). Along the Missouri River in Nebraska, Weaver [146] observed thickets of short-statured peachleaf willows on sandbars and banks, while stands of peachleaf willow trees grew on terraces. In Fort Collins, Colorado, rate of peachleaf willow establishment across 3 years ranged from 1.8 seedlings/m² to 2.6 seedlings/m². The substrate was moist alluvium and gravel in an abandoned gravel pit [109].

Factors reducing seedling establishment include drying of the substrate, altered hydrologic regimes, and interference from invasive nonnative trees, particularly saltcedar (Tamarisk spp.) and Russian-olive. Along the Arkansas River in Kansas, peachleaf willow and sandbar willow were more abundant on sites with low plains cottonwood and/or saltcedar numbers [35]. See Altered succession for further details.

Vegetative regeneration: Peachleaf willow regenerates vegetatively by sprouting from the root crown ([117], review by [151]) and/or stem [66,117], by layering, and by rooting of broken stem and branch segments (review by [151]). It does not root sprout ([117], Zasada 2012 personal communication [152]). A greenhouse study using peachleaf willow stem cuttings found most of peachleaf willow's adventitious buds were located above ground, although some were below ground [117].

Flood control can decrease peachleaf willow sprouting and seedling establishment. Willow regeneration failure has been noted on rivers subject to flood-control regulation from Alberta to Arizona [127]. On regulated, lowland areas of the South Fork Republican River, peachleaf willow sprouts and adults tended to occur on terraces and seedlings were rare. In upstream areas without flood regulation, sprouts and adults were more abundant in scour zones than on terraces, and seedlings occurred on moist, bare substrates in scour zones [64,65]. Following a large flood of the South Fork Republican River in 1915 and a record flood in 1935, root crown sprouts were more common for peachleaf willows than for plains cottonwoods. Peachleaf willow and plains cottonwood seedlings established only on scoured floodplains lacking trees, while Russian-olive seedlings established on both floodplains and terraces beneath tree canopies [64].

Plant growth: Peachleaf willow may grow more slowly than associated willow species. Generally, its sprouts grow more rapidly than its seedlings. Peachleaf willow seedlings may initially gain more root than aboveground biomass [89]. In Fort Collins, Colorado, mean height of 3-year-old peachleaf willow seedlings was 5.9 inches (15.1 cm). The seedlings established in an abandoned gravel pit [110].

Peachleaf willow siblings gained less biomass in 1 to 2.5 years than Missouri River willow, narrowleaf willow, and shining willow siblings in a common garden in Ontario. However, this difference might have occurred because peachleaf willow was less adapted to the well-drained soils of the common garden than the other willow species. Peachleaf willow siblings were collected from either poorly drained or permanently inundated sites. Missouri River willow and narrowleaf willow were collected from moist but well-drained soils near fast-flowing streams [6,89]. A greenhouse study using stem cuttings found growth rate of peachleaf willow was intermediate between growth of basket willow (S. viminalis, the fastest) and Missouri River willow (the slowest), averaging 15.2 inches (38.6 cm) in stem length 4 weeks after planting. Peachleaf willow plants grew the fewest number of stems (1.2 stems/root crown). In an outside nursery, 4-year-old, coppiced peachleaf willows had the fewest live stems and the highest rate of stem die-off among the 3 willow species. After one growing season, peachleaf willow averaged about 18 sprouts/root crown [117].

See Aravanopoulos and Zsuffa [6] for a model predicting biomass growth of peachleaf willow. The model was developed in southern Ontario [6].

Peachleaf willow is not shade tolerant [141]. In urban forest islands of St Paul, Minnesota, peachleaf willow was positively associated with open, early-successional floodplains [52]. On floodplains of the Republican River, Kansas, peachleaf willow seedlings established on open sites, but they did not establish in mature plains cottonwood or American elm stands [11].

Peachleaf willow is characteristic and often dominant in early floodplain succession (for example, [45,98,134,135]). Floods that create or expose sandbars and mudflats may encourage establishment of peachleaf willow and other pioneering woody species. Without further disturbances, seedling establishment is usually limited to the first 1 to 5 years after scouring [20]. On floodplains of the Republican River, Kansas, peachleaf willow, black willow, and plains cottonwood established on alluvium 1 to 2 years after it was deposited. Although black willow was initially dominant, peachleaf willow and plains cottonwood overtopped black willow in 8 to 10 years. Peachleaf willow rarely persisted on these sites for more than 30 years. The authors suggested that canopy closure was responsible for peachleaf willow's successional decline. After about 100 years—as the plains cottonwoods died—these communities succeeded to mixed-deciduous American elm/common hackberry communities [11]. On braided channels of the Milk River, Montana, peachleaf willow and sandbar willow were the only woody species growing on sites where spring ice scouring had occurred 2 years prior [122]. In northern Minnesota, peachleaf willow established on the newly-exposed bottom of Sunken Lake after a gravel ridge slumped and the lake drained. Peachleaf willow established on sandy sites of the old lake bottom but not on peaty sites. The old lake site was surrounded by a white pine-jack pine-quaking aspen (Populus tremuloides) forest [93].

Across riparian zones of the Great Plains, peachleaf willow and other willows are generally replaced by cottonwoods, then green ash, boxelder, and/or elms as succession proceeds (for example, [3,45,98,134,135,146]). In plains cottonwood/willow communities on the Yellowstone River floodplain, peachleaf willow and plains cottonwood seedlings formed thickets on new sand- and gravelbars. Peachleaf willow seedlings overtopped plains cottonwood seedlings initially, but plains cottonwoods grew taller and assumed dominance after 20 years [12]. Peachleaf willow was rare in mature plains cottonwood stands [13]. On sites without plains cottonwood, green ash replaced peachleaf willow successionally; no timeline was given for this succession [12]. By the Knife River of west-central North Dakota, peachleaf willow and plains cottonwood regeneration was absent in mature plains cottonwood/peachleaf willow communities. Most seedlings and saplings in the understories were green ash, with some American elm and boxelder. Green ash was expected to dominate in late succession [17]. In Montana, peachleaf willow is characteristic of riparian communities in primary succession, often succeeding to boxelder/common chokecherry or green ash/common chokecherry community types [45]. In southern Alberta [135] and Saskatchewan [134], the peachleaf willow community type is succeeded by yellow willow (S. lutea)/red-osier dogwood or green ash community types.

Along the Bighorn River of Wyoming, peachleaf willow was most common in the understory of young (5-29 years) plains cottonwood woodlands. Russian-olive displaced peachleaf willow in middle-aged (30-54 years) woodlands, when most peachleaf willows and narrowleaf willows were dead or dying. No living willows were present in woodlands older than 79 years. In middle-aged and older woodlands, fire-scarred and fire-killed plains cottonwoods gave evidence of past fires. Trees in young and middle-aged woodlands showed evidence of American beaver damage [4].

A post-Dust Bowl survey (early 1940s) taken along the Niobrara River in Cherry County, Nebraska, found sandbar willow established on recently deposited sand, while peachleaf willow and plains cottonwood were most common on stabilized sandbars. These early-seral stages were not frequent: Most riparian communities were in late succession and dominated by American elm and boxelder. Underrepresentation of early-seral riparian communities was attributed to die-off of willows and cottonwoods during the drought [138].

In foothills and mountains of Wyoming, peachleaf willow may dominate early stages of succession in Engelmann spruce-Rocky Mountain lodgepole pine-subalpine fir forests, and persist in open understories as a common to dominant species [97].

Hansen [43] noted that in eastern Montana, peachleaf willow, plains cottonwood, and boxelder sometimes invaded moist grasslands. As wetlands dried, plant communities often transitioned from Sphagnum bogs to reed canarygrass-reed grass-foxtail barley (Phragmites communis-Hordeum jubatum) wet grasslands to deciduous woodlands that could contain peachleaf willow [43].

Altered succession: Flooding restrictions and/or invasion by nonnative woody species may reduce recruitment of peachleaf willow and other native woody species in riparian zones [127]. Low peachleaf willow recruitment was noted along dammed sections of the upper Missouri River in North Dakota; decline of peachleaf willow and plains cottonwood was linked to cessation of flooding and other alterations in the hydraulic regime [58,59]. A study along the Middle Snake River of southern Idaho suggested that mixed-deciduous woodlands dominated by nonnatives have increased in area since the late 1930s. The authors attributed this increase to reduced flooding and invasion by Russian-olive and saltcedar. Peachleaf willow was the most common native species codominating these nonnative riparian woodlands [24]. Along the Rio Grande of central New Mexico, flood control, coupled with rapid colonization by saltcedar and Russian-olive, has restricted establishment of plains cottonwood in gallery forests. Peachleaf willow dominanted the subcanopy, but the authors predicted that without management intervention, saltcedar and Russian-olive would dominate the canopy in 50 to 100 years [55].

Altered hydrologic regimes can change successional trajectories even when nonnatives are not present. In the absence of flooding disturbance [20,59]—or less frequently, fire [4]—peachleaf willow, other willows, and cottonwoods are replaced successionally by green ash, boxelder, American elm, and/or bur oak [20,59].


SPECIES: Salix amygdaloides

Immediate fire effect on plant:
Most fires top-kill peachleaf willow. Severe fires that burn into the soil organic layer, charring the roots and root crown, may kill peachleaf willow [135].

Postfire regeneration strategy [130]:
Tree with adventitious buds and a sprouting root crown
Tall shrub, adventitious buds and a sprouting root crown
Small shrub, adventitious buds and a sprouting root crown
Initial off-site colonizer (off site, initial community)

Fire adaptations and plant response to fire:

Fire adaptations: Peachleaf willow is well-adapted to flooding disturbance, and its adaptations to flooding also enable it to establish and survive in early postfire environments that are moist. Flooding and fire adaptations include sprouting and establishing on moist sites from wind- or water-dispersed seed (see Regeneration Processes).

Peachleaf willow sprouts after top-kill by fire [43]. Hansen and others [45] speculate that peachleaf willow sprouts after "all but the hottest fires". Peachleaf willow may sprout from the root crown ([117], review by [151]), stems [66,117], and/or boles. On the Lee Metcalf Wildlife Refuge in Stevensville, Montana, large peachleaf willows sprouted from their root crowns, decumbent boles, or both after an April wildfire (Fryer 2009 personal observation).

Peachleaf willow root crown (above) and bole (below) sprouts at postfire year 3.
Photos taken at the Lee Metcalf National Wildlife Refuge by Janet Fryer, US Forest Service.

Peachleaf willow may also establish on new burns [135] from wind- or water-borne [20,150,151] seeds [135].

Plant response to fire: Peachleaf willow root crown and stem sprouts may grow rapidly when favorably moist conditions follow fire. As of 2012, rates of postfire sprout initiation and growth were not documented in the literature.

Because peachleaf willow relies on scouring and substrate deposition for seedling establishment, high-scour floods [64] are more important to peachleaf willow recruitment than fires. However, peachleaf willow seedlings may establish on a new burn if the fire exposed mineral soil on a favorably moist, open site. Small branch segments that float from upstream may also root and establish on new burns on the edges of watercourses.

More information is needed on the ability of peachleaf willow to regenerate after fire in different seasons, severities, and climate regimes.


Fuels: Riparian communities generally have higher biomass, basal area, stand density, and rates of plant reproduction than adjacent upland communities [92,131]. Fuel loads can therefore be large; however, in most years, riparian zones with peachleaf willow may be too moist to burn. Deciduous riparian plant communities often exhibit low fire incidence due to high moisture in potential fuels and rapid decomposition of litter [15]. However, some riparian areas are surrounded by greater and more continuous fuel accumulations than in the past [1]. The fuel buildups may increase fire severity in these surrounding forests, substantially impacting water flow and sediment transport in riparian areas [1,30].

Because peachleaf willow communities are moist year-round, they act as natural firebreaks in most years but may burn during drought years [43]. In Buffalo River State Park, Minnesota, early May prescribed fires burned through an upland big bluestem-switchgrass-little bluestem (Andropogon gerardii-Sorghastrum nutans-Schizachyrium scoparium) prairie. However, green ash-eastern cottonwood/peachleaf willow galleries on the Buffalo River floodplain had a "large amount of standing water" and failed to burn [50]. The following photo illustrates typical early spring fuels on the Lee Metcalf National Wildlife Refuge, Montana. A peachleaf willow stringer grows at the interface of a broad-leaved cattail marsh and an upland smooth brome (Bromus inermis) roadside community. A wildfire burned into part of the marsh, the peachleaf willow stringer, and up to the road in April 2009; these photos were taken in April 2012.

Standing and down fire-killed peachleaf willow stems and live peachleaf willow sprouts surrounded by smooth brome litter (foreground surface fuels) and broad-leaved cattail litter (background surface fuels). Photos by Janet Fryer, US Forest Service.

Along the Bighorn River, young plains cottonwood woodlands (5-29 years) had large accumulations of dead leaves and twigs but few fallen logs. Standing dead and downed woody debris became more common in middle-aged woodlands (30-54 years). Peachleaf willow was most common in young woodlands; its cover decreased with stand age. Fire-scarred and fire-killed plains cottonwoods gave evidence of past fires [4].

Fire regimes: Fires in areas containing riparian ecosystems may burn only the upland parts of the watershed, or they may burn both the riparian ecosystem and the upland areas. Fire rarely occurs only in a riparian ecosystem, however, unless it is prescribed [22]. The role riparian forests play in fire spread is poorly understood [30,121]. Riparian areas with heavy, continuous fuels may serve as corridors for rapid spread of fire [30] or reservoirs of smoldering fuels. Conversely, less dense or more mesic riparian areas may serve as firebreaks for surface fires [30]. Riparian microclimates are generally characterized by cooler air temperatures, lower daily maximum air temperatures, and higher relative humidities than the adjacent uplands, contributing to higher fuel moisture and presumably lowering the intensity, severity, and frequency of fire in riparian areas [5,27]. The lower wind speeds generally associated with riparian zones may result in less intense fire behavior, with decreased rates of spread, decreased flame lengths, and lower fireline intensities. However, steep canyons may serve as wind tunnels, increasing fire intensity in narrow valleys with riparian habitat. During droughts, weather and fuel conditions may become the primary determinants of fire behavior, and differences between fire behavior in riparian areas and uplands are likely to disappear [27]. When only upland areas burn, adjacent riparian areas may buffer the effects of fire on the watercourse [22].

Little is known about historical fire frequencies in prairie riparian zones and wetlands [62]. Although fires were common in the grasslands of the presettlement Great Plains (for example, [61,71]), how often prairie fires burned into cottonwood-willow gallery forests is unknown. Determining fire-return intervals in riparian areas is complicated due to the difficulty of dating fire scars in hardwoods (Swetnam 2001 personal communication [132]), presence of tree wounds from other disturbances (for example, ice flows), and the short life spans of most riparian hardwood species [1].

A review reported estimates of 20 to 30 years for historical fire-return interval of plains cottonwood communities along rivers [119]. These riparian areas burned less frequently than the surrounding uplands; fires skipped over or only burned only portions of the riparian zones [118]. Fires most likely occurred late in the growing season, when understory riparian vegetation was cured enough to support a fire.

Because of high moisture content and rapid decomposition of litter in riparian forests, historical fire frequency in black cottonwood communities was probably less than in adjacent upland areas. However, wind-driven fires beginning in upland communities may spread to adjacent riparian forests, particularly when fuel accumulation on upland sites has increased as a result of fire exclusion [123]. Arno [10] stated that historically, black cottonwood forests along major rivers of the Inland Northwest likely burned frequently because they were surrounded by communities with high fire frequencies, such as ponderosa pine savannas or mountain big sagebrush (Artemisia tridentata subsp. vaseyana) steppes. Fires could have easily spread from adjacent communities, particularly prior to widespread livestock grazing and irrigation, when dry grassy fuels were more continuous than they are currently [10]. When fires do occur in black cottonwood communities, they are most severe in old stands with heavy fuel accumulations ([37], review by [123]).

In riparian areas of the Southwest, fire frequencies may have increased since historic times because of saltcedar (Tamarix spp.) invasion [15], altered hydraulic regimes, and land development. For more information, see the FEIS species review of saltcedar.

See the Fire Regime Table for further information on fire regimes of vegetation communities in which peachleaf willow may occur. Find further 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".

Since peachleaf willow sprouts, prescribed or wildfires are unlikely to have any long-term negative effects on this species. However, because there are no data on peachleaf willow's postfire recovery to date (2012), managers may want to test fire effects in small areas before proceeding to larger-scale fire treatments in areas where peachleaf willow persistence is of concern. In riparian areas subject to flood control, Howe and others [55] suggested that burned areas may provide a partial substitute for flood-scoured areas, providing substrates for establishment of peachleaf willow, plains cottonwood, and other native, woody riparian species. Because peachleaf willow and other native riparian tree species disperse seed in early spring, late fall or winter prescribed fires may best prepare a seedbed timed for early spring establishment of willow and cottonwood seedlings.

In the Northern Great Plains, spread of peachleaf willow into prairie pothole communities in the first half of the 20th century may have been due to fire exclusion [69].


SPECIES: Salix amygdaloides

Information on state- and province-level protection status of plants in the United States and Canada is available at NatureServe.

Peachleaf willow and other willows are important, often primary, sources of browse for wild ungulates. They are particularly important for moose and elk [2,45,140]. Peachleaf willow communities in eastern Montana provide relatively moderate volumes of forage, but they are important forage areas for wild and domestic ungulates because they generally stay green throughout summer [43]. Cottontails [2,19] and American beavers also browse peachleaf willow twigs, and American beavers use the branches in dam construction [2].

Cattle generally prefer grazing grasses to browsing willows, but they may select peachleaf willow occasionally [99]. On the Roosevelt National Forest, Colorado, cattle in a riparian area browsed peachleaf willow in winter [29].

Cottonwood/willow (Populus/Salix spp.) communities provide habitat for a diverse assortment of animal species including wild ungulates, American beavers [127], birds [28,115,116,127], and insects [127]. This is particularly true in areas where the uplands are too dry to support trees [34]. In eastern Montana, green ash/chokecherry wooded draws with peachleaf willow provide habitat for mule deer. Peachleaf willow is among the woody species mule deer use as forage [136].

Many migratory birds nest in cottonwood-willow habitats; warblers and other foliage- or aerial gleaners are particularly prevalent [127]. In eastern South Dakota, bird species diversity was higher in cottonwood-willow riparian woodlands than in wooded shelterbelts and windbreaks (P=0.001). Peachleaf willow was often abundant in these communities [28]. Along the Snake River of Idaho, peachleaf willow and other willow communities supported more songbird, gamebird, and raptor species than Russian-olive communities [14]. Stevens and others [126] reported that cottonwood/willow habitats of Arizona support a density of migratory birds more than 10 times that of upland areas. Peachleaf willow and other willows provide habitat and nesting cover for the federally endangered southwestern willow flycatcher [142].

Southwestern willow flycatcher nest in a willow. USGS photo.

Many insects use peachleaf willow habitats; mosquitoes are especially noticeable in wetlands with peachleaf willow [43].

Palatability: Palatability of peachleaf willow browse is rated fair to good for domestic livestock, good for elk and mule deer, fair for white-tailed deer, and poor for pronghorn [45]. No information was available on its nutritional value as of 2012.

Cover value: Peachleaf willow provides good hiding and thermal cover for all categories of wildlife. It also provides shade cover for fish [43,44,45]. Its cover value is rated fair for waterfowl and good for upland game birds, songbirds, and small mammals [44,45].

Because peachleaf willow grows as either a tree or shrub, many different bird guilds use it for nesting, including branch, bole, and ground nesters. Along the North Platte and Laramie rivers in Wyoming, house wrens, hairy woodpeckers, and northern flickers nested in the boles of peachleaf willow trees [40]. Height and bole dimensions of peachleaf willows were apparently optimal for northern flickers [41]. On the South Platte River of northeastern Colorado, mourning doves used peachleaf willow trees and shrubs for daytime hiding cover and nested in peachleaf willow trees [19]. Ducks, including redheads, gadwalls, and cinnamon teals, use peachleaf willow as nesting cover in marshes of the Bear River Delta, Utah [149].

Willows are widely planted to stabilize stream- and riverbanks and reduce flood damage [140,141] and to enhance wildlife habitats [2]. Peachleaf willow is recommended for planting near stream edges, pond margins, and on other sites with saturated soils [101]. Several peachleaf willow cultivars have been developed for different regions of the United States. See the Natural Resources Conservation Service [141] for details. See these sources for information on propagation and planting peachleaf willow: [26,101,141,150,151].

Peachleaf willow may establish naturally on rehabilitation sites [109], although invasive species may also establish and need to be controlled. Near the Platte River in Nebraska, naturally established peachleaf willow seedlings grew on newly abandoned grain fields sown or planted with other native species. Peachleaf willow also established in prairie potholes in 3- to 14-year-old abandoned agricultural fields that had their natural drainages restored. However, most of these reflooded potholes became dominated by nonnative reed canarygrass and other invasive perennials, including native broad-leaved cattail. The authors stated that restoration of preagricultural species composition and structure is unlikely on similar prairie pothole wetlands without native plantings and follow-up maintenance [91]. In Fort Collins, Colorado, saltcedar (T. ramosissima) seedlings established in an abandoned gravel pit at densities nearly equal to those of peachleaf willow and plains cottonwood seedlings. Saltcedar seedlings were controlled by flooding the gravel pit in fall. This reduced saltcedar cover to 6.1%, while combined cover of peachleaf willow, plains cottonwood, and narrowleaf willow was 41.1% [109].

Willow twigs and branches are used in basketry [127,140]. Peachleaf willow does not coppice well [117], and the wood is too soft for most commercial uses.

American Indians used peachleaf willow medicinally, in basketry, for making cooking utensils and fish weirs, and in ceremonies [48,127]. Infusions of willow bark, including that of peachleaf willow, were used to treat pain and inflammation [48,127]. The active medicinal ingredient producing this effect, salicylic acid, is now manufactured synthetically (review by [127]). American Indians used periodic fire or pruning to encourage growth of long, straight stems for basketry [127].

Cottonwood-willow communities are vulnerable to overgrazing [70]. Because peachleaf willow is usually multistemmed and has relatively soft wood, it is susceptible to heavy trampling and rubbing by ungulates; with sustained heavy use, downed woody debris from such damage can render the area inaccessible to livestock [44,135]. Heavy livestock and/or wild ungulate use can alter plant species composition and community structure. These sources: [129,141] provide guidelines for managing cottonwood-willow communities as rangelands.

Peachleaf willow showed good recovery after livestock were excluded from sagebrush (Artemisia spp.) steppe in eastern Washington. Cattle, domestic sheep, and horses grazed Rattlesnake Springs, a homestead site, heavily from about 1900 to 1940. The site was incorporated into the Hanford Nuclear Reservation in 1943. An exclosure was built in 1963 to stop livestock from wandering onto the site, although mule deer and elk still had access. In 1963, peachleaf willow cover was "sparse and discontinuous" along the springs. By 1983, peachleaf willow had formed continuous borders around springs and showed "vigorous recovery"; this was attributed to the cessation of livestock use [108].

A study on the Roosevelt National Forest found peachleaf willow tolerated long-term cattle browsing more than associated planeleaf, Geyer, or narrowleaf willows. Relative abundance of peachleaf willow decreased with browsing pressure but was least on unbrowsed plots (P<0.05) [53].

Periodic flooding is usually required to maintain cottonwood-willow communities (see Successional Status). To promote establishment of peachleaf willow and other early-successional, native woody species, Johnson [58] recommends prescribed flooding, with peak flows that are voluminous enough to erode the outside curves of rivers and create pointbars on the inside curves.

A laboratory study found peachleaf willow was more resistant to cavitation and loss of water conductivity than saltcedar. The authors concluded that superior hydraulic capacity does not adequately explain saltcedar's ability to invade communities with peachleaf willow and other riparian species [104].


SPECIES: Salix amygdaloides

The following table provides fire regime information that may be relevant to peachleaf willow habitats. Find further 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".

Fire regime information on vegetation communities in which peachleaf willow is known or is likely to occur. This information is taken from the LANDFIRE Rapid Assessment Vegetation Models [76], which were developed by local experts using available literature, local data, and/or expert opinion. This table summarizes fire regime characteristics for each plant community listed. The PDF file linked from each plant community name describes the model and synthesizes the knowledge available on vegetation composition, structure, and dynamics in that community. Cells are blank where information is not available in the Rapid Assessment Vegetation Model.
Pacific Northwest Southwest Great Basin Northern and Central Rockies
Northern Great Plains Great Lakes South-central US Southern Appalachians
Pacific Northwest
Vegetation Community (Potential Natural Vegetation Group) Fire severity* Fire regime characteristics
Percent of fires Mean interval
Minimum interval
Maximum interval
Pacific Northwest Grassland
Alpine and subalpine meadows and grasslands Replacement 68% 350 200 500
Mixed 32% 750 500 >1,000
Pacific Northwest Forested
Douglas-fir-western hemlock (wet mesic) Replacement 71% 400    
Mixed 29% >1,000    
Vegetation Community (Potential Natural Vegetation Group) Fire severity* Fire regime characteristics
Percent of fires Mean interval
Minimum interval
Maximum interval
Southwest Grassland
Shortgrass prairie with trees Replacement 80% 15 2 35
Mixed 20% 60    
Southwest Woodland
Riparian deciduous woodland Replacement 50% 110 15 200
Mixed 20% 275 25  
Surface or low 30% 180 10  
Southwest Forested
Ponderosa pine-Douglas-fir (southern Rockies) Replacement 15% 460    
Mixed 43% 160    
Surface or low 43% 160    
Riparian forest with conifers Replacement 100% 435 300 550
Great Basin
Vegetation Community (Potential Natural Vegetation Group) Fire severity* Fire regime characteristics
Percent of fires Mean interval
Minimum interval
Maximum interval
Great Basin Grassland
Mountain meadow (mesic to dry) Replacement 66% 31 15 45
Mixed 34% 59 30 90
Great Basin Forested
Ponderosa pine-Douglas-fir Replacement 10% 250   >1,000
Mixed 51% 50 50 130
Surface or low 39% 65 15  
Northern and Central Rockies
Vegetation Community (Potential Natural Vegetation Group) Fire severity* Fire regime characteristics
Percent of fires Mean interval
Minimum interval
Maximum interval
Northern and Central Rockies Grassland
Mountain grassland Replacement 60% 20 10  
Mixed 40% 30    
Northern prairie grassland Replacement 55% 22 2 40
Mixed 45% 27 10 50
Northern and Central Rockies Shrubland
Riparian (Wyoming) Mixed 100% 100 25 500
Northern and Central Rockies Forested
Douglas-fir (cold) Replacement 31% 145 75 250
Mixed 69% 65 35 150
Mixed-conifer upland western redcedar-western hemlock Replacement 67% 225 150 300
Mixed 33% 450 35 500
Ponderosa pine-Douglas-fir Replacement 10% 250   >1,000
Mixed 51% 50 50 130
Surface or low 39% 65 15  
Western redcedar Replacement 87% 385 75 >1,000
Mixed 13% >1,000 25  
Northern Great Plains
Vegetation Community (Potential Natural Vegetation Group) Fire severity* Fire regime characteristics
Percent of fires Mean interval
Minimum interval
Maximum interval
Northern Plains Grassland
Central tallgrass prairie Replacement 75% 5 3 5
Mixed 11% 34 1 100
Surface or low 13% 28 1 50
Nebraska Sandhills prairie Replacement 58% 11 2 20
Mixed 32% 20    
Surface or low 10% 67    
Northern mixed-grass prairie Replacement 67% 15 8 25
Mixed 33% 30 15 35
Northern tallgrass prairie Replacement 90% 6.5 1 25
Mixed 9% 63    
Surface or low 2% 303    
Southern mixed-grass prairie Replacement 100% 9 1 10
Southern tallgrass prairie (East) Replacement 96% 4 1 10
Mixed 1% 277    
Surface or low 3% 135    
Northern Plains Woodland
Great Plains floodplain Replacement 100% 500    
Northern Great Plains wooded draws and ravines Replacement 38% 45 30 100
Mixed 18% 94    
Surface or low 43% 40 10  
Great Lakes
Vegetation Community (Potential Natural Vegetation Group) Fire severity* Fire regime characteristics
Percent of fires Mean interval
Minimum interval
Maximum interval
Great Lakes Forested
Conifer lowland (embedded in fire-prone ecosystem) Replacement 45% 120 90 220
Mixed 55% 100    
Conifer lowland (embedded in fire-resistant ecosystem) Replacement 36% 540 220 >1,000
Mixed 64% 300    
Great Lakes floodplain forest Mixed 7% 833    
Surface or low 93% 61    
Great Lakes pine forest, jack pine Replacement 67% 50    
Mixed 23% 143    
Surface or low 10% 333    
Great Lakes spruce-fir Replacement 100% 85 50 200
Maple-basswood Replacement 33% >1,000    
Surface or low 67% 500    
Maple-basswood mesic hardwood forest (Great Lakes) Replacement 100% >1,000 >1,000 >1,000
Minnesota spruce-fir (adjacent to Lake Superior and Drift and Lake Plain) Replacement 21% 300    
Surface or low 79% 80    
South-central US
Vegetation Community (Potential Natural Vegetation Group) Fire severity* Fire regime characteristics
Percent of fires Mean interval
Minimum interval
Maximum interval
South-central US Grassland
Southern shortgrass or mixed-grass prairie Replacement 100% 8 1 10
Southern tallgrass prairie Replacement 91% 5    
Mixed 9% 50    
South-central US Forested
Southern floodplain Replacement 42% 140    
Surface or low 58% 100    
Southern floodplain (rare fire) Replacement 42% >1,000    
Surface or low 58% 714    
Southern Appalachians
Vegetation Community (Potential Natural Vegetation Group) Fire severity* Fire regime characteristics
Percent of fires Mean interval
Minimum interval
Maximum interval
Southern Appalachians Forested
Bottomland hardwood forest Replacement 25% 435 200 >1,000
Mixed 24% 455 150 500
Surface or low 51% 210 50 250
Mixed-mesophytic hardwood Replacement 11% 665    
Mixed 10% 715    
Surface or low 79% 90    
*Fire Severities—
Replacement: Any fire that causes greater than 75% top removal of a vegetation-fuel type, resulting in general replacement of existing vegetation; may or may not cause a lethal effect on the plants.
Mixed: Any fire burning more than 5% of an area that does not qualify as a replacement, surface, or low-severity fire; includes mosaic and other fires that are intermediate in effects.
Surface or low: Any fire that causes less than 25% upper layer replacement and/or removal in a vegetation-fuel class but burns 5% or more of the area [42,75].


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