|© 2006 Vivian Parker|
According to Cronquist and others , woods strawberry and Virginia strawberry (Fragaria virginiana) do not hybridize in the western U.S., and any similarities in diagnostic traits are more likely attributable to variability within species.
For the purposes of this review, the common name "woods strawberry" is used when discussing
characteristics common to (or assumed to be common to) the species in general. When referring to infrataxa,
the scientific names for the subspecies listed above are used. When referring to multiple Fragaria spp.,
the name "wild strawberries" is used.
FEDERAL LEGAL STATUS:
No special status
Information on state-level protected status of plants in the United States is available at Plants Database.
In Canada, woods strawberry occurs from coastal British Columbia east to Newfoundland [37,61,72,79,80,90,107,125,134,134,173], as well as in Northwest Territories . It also occurs in Baja California, Mexico [37,78,108,175].
Globally, woods strawberry distribution is circumboreal [98,99]. While it is widely considered a native species in North America, at least some populations may originate from introduced European stock [61,111,141], especially in the northeastern United States and adjacent Canada [61,80,134,141], and the northern Great Plains .
Comprehensive surveys examining the presence or absence of woods
strawberry within the following biogeographic vegetation schemes are not available. These lists represent a
"best estimate" of woods strawberry occurrence based on information obtained from floras and other
literature, herbarium samples, and confirmed observations.
FRES10 White-red-jack pine
FRES13 Loblolly-shortleaf pine
FRES21 Ponderosa pine
FRES22 Western white pine
FRES24 Hemlock-Sitka spruce
FRES26 Lodgepole pine
FRES28 Western hardwoods
FRES30 Desert shrub
FRES33 Southwestern shrubsteppe
FRES34 Chaparral-mountain shrub
FRES37 Mountain meadows
FRES38 Plains grasslands
FRES40 Desert grasslands
FRES41 Wet grasslands
STATES/PROVINCES: (key to state/province abbreviations)
Woods strawberry is a low-growing, deciduous perennial herb [6,27,37,62,63,72,73,90,99,108,120,126,145,154, 173,175], with petioles and flowering stems typically arising from a single crown in rosette form. Occasionally a single crown may split into 2 or more crowns by the development of an axillary meristem, but production of leaves and flowers is generally restricted to a single meristematic axis in each ramet . Petioles are generally 0.3 to 6.9 inches (0.8-17.5 cm) long [37,78,80,173], with flowering stems often shorter . Leaves are basal and palmately trifoliate [37,62,63,72,78,79,80,90,99,108,120,141,145,154, 173,175], with leaflets 0.5 to 2.6 inches (1.3-6.5 cm) long and 0.5 to 2.8 inches (1.3- 7.0 cm) wide [37,78,108,145,173], the terminal leaflet being largest [37,173]. Flowers of Fragaria vesca ssp. vesca, F. v. ssp. americana, and F. v. ssp. californica are exclusively perfect, while F. v. ssp. bracteata produces occasional female-only plants . Fleshy fruits are up to 0.4 inch (1 cm) thick and covered with 0.05 inch (1.3-1.4 mm) long achenes [37,62,78,80,108,126,173]. Crowns arise from short rhizomes [63,78,90,99,108,126], spreading and forming colonies by stolons that root and produce plantlets at the nodes [37,47,62,63,72,73,78,80,90,99,108,120,126,145, 154,173,175].RAUNKIAER  LIFE FORM:
Pollination: According to Ostler and Harper , woods strawberry is "animal-pollinated", and flower structure is open with "unrestricted access to nectaries and/or pollen."
Breeding system: Fragaria vesca. ssp. vesca, F. v. ssp. americana, and F. v. ssp. californica have perfect flowers. Fragaria vesca ssp. bracteata is gynodioecious, in which most plants have perfect flowers, but occasionally some plants bear only female flowers .
Seed production: No information is available on this topic.
Seed dispersal: Seeds are probably dispersed by birds and mammals (Martin and others 1951, as cited in ), .
Seed banking: Although information describing longevity of viable, soil-stored woods strawberry seed is sparse, there is some indication that it does develop seed banks ( and references contained therein). Laboratory and field research in Europe indicate that viable woods strawberry seeds may persist in soil for at least 5 years .
It appears that the woods strawberry seed bank is found close to the soil surface. Kramer and Johnson  studied seed banks in Douglas-fir and grand fir forests in west-central Idaho. A total of 19 viable woods strawberry seeds were collected from 12 of 48 stands sampled. Ninety-five percent of viable woods strawberry seeds were found in the 0 to 2 inch (0-5 cm) depth, which was mainly composed of compacted litter and organic layers. Five percent of viable woods strawberry seeds were found in the 2 to 4 inch (5-10 cm) depth, which was predominantly mineral soil . Similarly, of soil samples taken from 3 grand fir-dominated sites in the Blue Mountains of eastern Oregon, 2 sites yielded germinable seeds only from the litter/humus layer, and 1 site only from the 0 to 0.8 inch (0-2 cm) mineral soil layer. No woods strawberry seedlings emerged from the 0.8 to 1.6 inch (2-4 cm) soil samples .
Germination: As of this writing (2007) there is little published information describing conditions either favoring or inhibiting woods strawberry seed germination. Steele and Geier-Hayes  wrote that woods strawberry "germinates on moist mineral soil in partial shade."
Results from a laboratory experiment suggest that cold stratification may induce more rapid germination of woods strawberry seed but provides a much smaller, perhaps negligible effect on eventual numbers of germinants. Woods strawberry seeds were planted in sterilized soil and overwintered in either a coldframe or a heated greenhouse. Seeds overwintered in coldframes were brought indoors after 83 days and had greater germination (45.5%) compared with seeds from the heated greenhouse (32%). Seeds in the cold frame treatment also germinated more rapidly, between 14 and 56 days, while those in the heated greenhouse required between 48 and 252 days for germination .
Seedling establishment/growth: To date (2007), not much information has been published about woods strawberry seedling establishment and growth. However, there is some indication that seedling establishment occurs mainly apart from established populations, perhaps following some type of soil disturbance. A review by Eriksson  suggests that seedling establishment in preestablished populations of adult woods strawberry clones is rare, and that seedlings mainly contribute to establishment of new populations apart from established clones. Anecdotal evidence provided by Jurik  concurs, noting not only that seedlings do not seem to establish in preexisting populations, but that seedlings were observed only where the original vegetation was removed and mineral soil exposed. Steele and Geier-Hayes [148,150,151] noted that woods strawberry seedling establishment apparently requires bare shaded soil.
Asexual regeneration: Vegetative spread in woods strawberry occurs in 3 ways; although, according to a review by Eriksson , woods strawberry vegetative spread is mainly by stolons. Crowns arise from short rhizomes [63,78,90,99,108,126], and stolons arise from axillary buds, with individual ramets producing 1 to 4 stolons per season. Stolons may branch at alternate nodes. The nonbranching nodes produce 1 to 2 small leaves and adventitious root primordia, and will root when contacting moist substratum. Stolons decay over winter. Individual nodes may root up to 3.3 feet (1 m) from the parent ramet. Adventitious roots may also develop in the axils of decayed leaves allowing plants to "creep along the forest floor . . . through the accumulation of several years' decaying leaf bases" .SITE CHARACTERISTICS:
In western North America, woods strawberry also commonly occurs in, but is not always restricted to, wooded or forested habitats. Although comprehensive surveys are lacking, it appears that woods strawberry can be found in all but the driest forest types in the western United States. Woods strawberry occurrence in forested habitats in this region is often associated with relatively recent disturbance. Examples include forest openings [27,62,72,122], roadsides [71,105], and recently cleared or early successional forest  (also see Successional Status below). Woods strawberry occurrence in western North America is also documented in meadows [47,48,49,79,108], open slopes [73,108], prairie-woodland mosaics , forest margins , and margins of meadows . Reed  mentions woods strawberry occurrence in big sagebrush (Artemisia tridentata) habitats in Jackson Hole, Wyoming, although to date (2007) this is the only example encountered for this habitat.
Elevation: In mountainous western North America, woods strawberry occurrence has been reported from a wide range of elevations. Examples of such reports include: "low" to subalpine along the Pacific Northwest coast , "low to middle elevations" in Glacier National Park , and valley bottom to lower subalpine in west-central Montana . Knight and others  indicated that woods strawberry's preferred habitat in the Medicine Bow Mountains of northern Colorado/southern Wyoming is "higher elevation, mesic sites."
The following table lists published accounts of elevation ranges where woods strawberry occurs in western North America. These examples are not necessarily elevational limits to woods strawberry distribution, but rather a range of elevations, particularly upper elevations, where woods strawberry might occur.
|east-central and southeastern Arizona||7,000 to 9,500 feet (2,100-2,900 m) |
|southeastern Arizona||>9,200 feet (2,800 m) |
|southern Arizona||7,900 to 8,000 feet (2,400 m) |
|California||100 to 6,500 feet (30-2,000 m) |
|Sierra Nevada Range, California||<6,000 feet (1,800 m) |
|Colorado||5,000 to 9,500 feet (1,500-2,900 m) |
|near Crested Butte, Colorado||8,500 to 12,500 feet (2,600-3,800 m) |
|west-central Idaho||5,000 to 7,800 feet (1,500-2,400 m) |
|New Mexico||6,500 to 10,000 feet (2,000-3,000 m) |
|Utah||6,000 to 10,500 feet (1,800-3,200 m) |
|Uinta Basin, Utah||7,000 to 10,500 feet (2,100-3,200 m) |
|Cascade and Olympic Mountains, Washington||up to 4,000 feet (1,200 m) [79,80]|
|northwestern Wyoming||7,900 feet (2,400 m) |
|Intermountain West||5,900 to 7,900 feet (1800-2400 m) |
|Yellowstone National Park||6,000 to 7,600 feet (1,800-2,300 m) |
|Baja California||"higher foothills to about" 8,200 feet (2,500 m) |
The following table provides woods strawberry distribution data by elevation in the Siskiyou Mountains of Oregon and California, and is adapted from .
|Elevation range (feet)||1,500-2,500||2,500-3,500||3,500-4,500||4,500-5,500||5,500-6,300||6,300-7,000|
|Percent frequency of occurrence||0.6||1.1||5.9||10.2||7.0||4.5|
As of this writing (2007) there is no published information regarding elevation and woods strawberry distribution in eastern North America.
Moisture: Based on general information contained in site
descriptions, habitat types, etc., it appears that woods strawberry occurs under a wide range of
moisture conditions, although it is probably not tolerant of extremely wet or dry conditions. Although
comprehensive, rangewide information about moisture conditions for woods strawberry habitat is lacking, the
following descriptions provide some guidelines, at least for parts of the western United States. Lackschewitz
 indicated that woods strawberry occurs on sites in west-central Montana that are mesic (adequate moisture
during all or most of the growing season, but rarely if ever flooded) to meso-xeric (moisture abundant in the
early growing season but dry later on). Franklin and Dyrness  indicated that woods strawberry is more common
in warm, dry forests, less common in cool, moist forests, and rare to nonexistent in cold, moist forests of the
South Umpqua River valley, western Oregon.
Although evidence is limited, it appears that woods strawberry is most prevalent in early successional forests in the western United States. Nevertheless, it also appears that it may be found in most, if not all, successional stages of forest development, at least within some western forest types. For example, Antos and Habeck  sampled vegetation in grand fir-dominated communities in the Swan Valley, western Montana. Average woods strawberry percent occurrence was significantly (P<0.05) greater in stands less than 90 years old (67%), compared with stands greater than 150 years old (7%) . Habeck  also studied succession in western redcedar (Thuja plicata)-western hemlock (Tsuga heterophylla) zone forest communities in Glacier National Park. Woods strawberry exhibited its greatest presence in the earliest stages of succession in this zone, where forests that had established following fire were dominated by Rocky Mountain lodgepole pine (Pinus contorta var. latifolia) and, to a lesser extent, western larch (Larix occidentalis). Woods strawberry diminished in importance in later-successional communities where western redcedar and western hemlock were dominant . Spies  found that mean woods strawberry percent frequency of occurrence in the Oregon Cascades was significantly (P<0.05) lower in old-growth (mean age = 395 years) forest stands, compared with mature (mean age = 115 years) or young (mean age = 60 years) stands. However, Steele and Geier-Hayes [147,148,149,150,151,152] characterized woods strawberry as a midseral species in several Douglas-fir- and grand fir-dominated habitat types in Idaho, and Ross and Hunter  included woods strawberry among "dominants in the climax vegetation" of the western redcedar-western hemlock association in Montana.
Several sources suggest or demonstrate that woods strawberry presence in western forest habitats is enhanced by disturbance. Hall  indicated that wild strawberries tend to increase with site disturbance in the Blue Mountains of eastern Oregon and southeastern Washington. Ferguson and others  indicated that woods strawberry increased substantially in response to both partial and total overstory removal in grand fir-dominated sites in northern Idaho and southeastern Oregon. Green and Jensen  noted that stands of grand fir (grand fir/wild ginger (Asarum caudatum) habitat type) that were subjected to clearcutting, broadcast burning, and high-intensity mechanical scarification resulted in a woods strawberry-thistle (Cirsium spp.) successional community. Nelson and Halpern  studied the responses of understory plants to aggregated retention harvests in 70 to 80-year-old and 110 to 140-year-old Douglas-fir-dominated forests on the western slope of the Cascade Range, southwestern Washington. Aggregates were 2.5 acres (1 ha), with 5 aggregates retained per 32-acre (13 ha) harvest unit. Sampling did not detect woods strawberry in preharvest plots of either the harvested or retention treatments, nor in postharvest retention units 1 to 2 years after cutting. However, woods strawberry was sampled at 3% frequency in harvested areas, with mean cover less than 0.05% . A thinning experiment in a central Colorado Rocky Mountain lodgepole pine forest showed that woods strawberry cover was significantly (P<0.05) greater 5 years after heavy thinning (average basal area 30 ft²/acre), compared with moderate thinning (58 ft²/acre), light thinning (73 ft²/acre), and unthinned controls (basal area not reported) .
It is not clear if observed increases in woods strawberry associated with site disturbance are due to seedling establishment that is promoted by litter layer and soil disturbance (see Seedling Establishment/Growth). It is also possible that extant woods strawberry populations are released from competition for light by disturbance-induced changes in canopy structure, and expand their coverage by vegetative spread (see Asexual Regeneration). Although Kemball and others  considered woods strawberry to be shade intolerant, Steele and Geier-Hayes  indicated that woods strawberry is more shade tolerant than many of the early seral herb-layer species with which it is often associated in Idaho forests, and that it, along with Virginia strawberry, achieves its greatest coverage "beneath a light canopy of trees or tall shrubs where partial shade has reduced competition from earlier successional herbs" .SEASONAL DEVELOPMENT:
|east-central/southeastern Arizona ||X||X||X||X||X|
|near Moscow, Idaho ||X||X|
|northern Idaho ||X||X||X|
|New Mexico ||X||X||X||X||X||X|
|western North Carolina ||X||X||X|
|western Oregon/southwestern Washington ||X||X||X|
|Uinta Basin, Utah ||X||X|
|West Virginia ||X||X||X|
|Blue Ridge Mountains ||X||X||X|
|northern Great Plains ||X||X|
|Intermountain West ||X||X|
|New England ||X||X|
|northeastern United States ||X||X||X|
|coastal, New York to Newfoundland ||X||X||X||X|
|Baja California ||X||X||X||X|
Reported dates for ripe fruits include mid-June to early August near Moscow, Idaho , and by early July in central New York . Stolon production occurs from early June to late August in central New York  and early May through August near Ithaca, New York . Stolon decay begins in late summer and connection between nodes is usually lost by spring, at least in central New York .
Leaf production occurs continuously from April to October in central New York, and a few leaves may overwinter . Steele and Geier-Hayes [150,151] also reported that at least some woods strawberry leaves remain green through the winter in Idaho.
Schmidt and Lotan  reported the following phenological data for woods strawberry from locations east of the Continental Divide in Montana and in Yellowstone National Park, 1928-1937:
|First appearance||Leaves full grown||Flowers start||Flowers end||Fruits ripe||Seed fall starts||Leaves start to color||Leaves fallen|
There is also some suggestion that, at least at the population level, woods strawberry is adapted to fire-prone habitats due to a propensity for postfire seedling establishment. In a study of postfire plant cover in northeastern Oregon, Johnson  indicated that in postfire year 5, woods strawberry established by seed dispersed from outside the measurement plots in a grand fir-pinegrass habitat type. Suggestions that woods strawberry seedling establishment is generally benefited by some type of disturbance (see Seedling Establishment and Growth and Successional Status) also supports the hypothesis that woods strawberry seedling establishment is promoted by fire. In addition, Strickler and Edgerton  suggested that heat may promote woods strawberry seed germination, but a small sample size provided limited experimental evidence.
Although several sources have suggested that seedling establishment and vegetative spread typically do not occur together concurrently, at least within established populations (see Seedling Establishment and Growth), Ahlgren [3,4] observed both woods strawberry seedling establishment and vegetative sprouting, in about equal numbers, in postfire experiment plots in northeastern Minnesota.
Fire regimes: As of this writing (2007), there is little published information linking woods strawberry with specific fire regimes. To the extent that woods strawberry benefits from fire (see Fire Effects), and to the extent that other postfire site characteristics are suitable for its occurrence, it is reasonable to suggest that woods strawberry is likely to be found in areas that experience moderately frequent, relatively low-severity fires. For example, Atzet and McCrimmon  described the fire regime of an Oregon white oak/woods strawberry habitat type in the southern Oregon Cascades as follows: "Fire occurred on three of the four sites sampled. Frequency is high, intensity is low, and many fires are confined to the type, without entering adjacent dense forest sites. Spread rates are moderated by the gentle topography. Heavy fuel production is low, but flashy fuels (grasses) are abundant and dry early in the summer. Vertical and horizontal fuel distribution is discontinuous and varied. Surface area, except for the grasses, is low" .
This is not to suggest that woods strawberry does not occur in areas with starkly different fire regimes than described above. For instance, it may be found in plant communities and ecosystems where the predominant disturbance type is something other than fire, such as windthrow, that may nevertheless benefit woods strawberry (see Successional Status). Given its apparent ubiquity across North America (see Distribution and Occurrence), fire regime is likely just one of many factors influencing woods strawberry occurrence and abundance.
The following table provides fire return intervals for plant communities and ecosystems where woods strawberry likely occurs (although precise distribution information is limited). 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)|
|silver fir-Douglas-fir||Abies amabilis-Pseudotsuga menziesii var. menziesii||>200|
|grand fir||Abies grandis||35-200 |
|maple-beech||Acer-Fagus spp.||684-1,385 [34,168]|
|silver maple-American elm||Acer saccharinum-Ulmus americana||<5 to 200|
|sugar maple||Acer saccharum||>1,000|
|sugar maple-basswood||Acer saccharum-Tilia americana||>1,000 |
|birch||Betula spp.||80-230 |
|California montane chaparral||Ceanothus and/or Arctostaphylos spp.||50-100 |
|sugarberry-America elm-green ash||Celtis laevigata-Ulmus americana-Fraxinus pennsylvanica||<35 to 200 |
|mountain-mahogany-Gambel oak scrub||Cercocarpus ledifolius-Quercus gambelii||<35 to <100 |
|Atlantic white-cedar||Chamaecyparis thyoides||35 to >200|
|beech-sugar maple||Fagus spp.-Acer saccharum||>1,000|
|black ash||Fraxinus nigra||<35 to 200 |
|green ash||Fraxinus pennsylvanica||<35 to >300 [52,168]|
|western juniper||Juniperus occidentalis||20-70|
|Rocky Mountain juniper||Juniperus scopulorum||<35 |
|cedar glades||Juniperus virginiana||3-22 [68,121]|
|tamarack||Larix laricina||35-200 |
|western larch||Larix occidentalis||25-350 [12,18,42]|
|yellow-poplar||Liriodendron tulipifera||<35 |
|Great Lakes spruce-fir||Picea-Abies spp.||35 to >200|
|northeastern spruce-fir||Picea-Abies spp.||35-200 |
|Engelmann spruce-subalpine fir||Picea engelmannii-Abies lasiocarpa||35 to >200 |
|black spruce||Picea mariana||35-200|
|conifer bog*||Picea mariana-Larix laricina||35-200 |
|blue spruce*||Picea pungens||35-200 |
|red spruce*||Picea rubens||35-200 |
|Rocky Mountain bristlecone pine||P. aristata||9-55 [45,46]|
|whitebark pine*||Pinus albicaulis||50-200 [1,9]|
|jack pine||Pinus banksiana||<35 to 200 [34,50]|
|Rocky Mountain lodgepole pine*||Pinus contorta var. latifolia||25-340 [17,18,161]|
|Sierra lodgepole pine*||Pinus contorta var. murrayana||35-200 |
|shortleaf pine||Pinus echinata||2-15|
|shortleaf pine-oak||Pinus echinata-Quercus spp.||<10 |
|Jeffrey pine||Pinus jeffreyi||5-30|
|western white pine*||Pinus monticola||50-200|
|Pacific ponderosa pine*||Pinus ponderosa var. ponderosa||1-47 |
|interior ponderosa pine*||Pinus ponderosa var. scopulorum||2-30 [11,16,101]|
|Arizona pine||Pinus ponderosa var. arizonica||2-15 [16,35,140]|
|red pine (Great Lakes region)||Pinus resinosa||3-18 (x=3-10) [33,58]|
|red-white pine* (Great Lakes region)||Pinus resinosa-P. strobus||3-200 [34,75,106]|
|pitch pine||Pinus rigida||6-25 [30,76]|
|eastern white pine||Pinus strobus||35-200|
|eastern white pine-eastern hemlock||Pinus strobus-Tsuga canadensis||35-200|
|eastern white pine-northern red oak-red maple||Pinus strobus-Quercus rubra-Acer rubrum||35-200|
|loblolly pine||Pinus taeda||3-8|
|loblolly-shortleaf pine||Pinus taeda-P. echinata||10 to <35|
|Virginia pine||Pinus virginiana||10 to <35|
|Virginia pine-oak||Pinus virginiana-Quercus spp.||10 to <35|
|sycamore-sweetgum-American elm||Platanus occidentalis-Liquidambar styraciflua-Ulmus americana||<35 to 200 |
|eastern cottonwood||Populus deltoides||<35 to 200 |
|aspen-birch||Populus tremuloides-Betula papyrifera||35-200 [50,168]|
|quaking aspen (west of the Great Plains)||Populus tremuloides||7-120 [11,66,110]|
|black cherry-sugar maple||Prunus serotina-Acer saccharum||>1,000 |
|mountain grasslands||Pseudoroegneria spicata||3-40 (x=10) [10,11]|
|Rocky Mountain Douglas-fir*||Pseudotsuga menziesii var. glauca||25-100 [11,13,14]|
|coastal Douglas-fir*||Pseudotsuga menziesii var. menziesii||40-240 [11,112,131]|
|California mixed evergreen||Pseudotsuga menziesii var. menziesii-Lithocarpus densiflorus-Arbutus menziesii||<35|
|California oakwoods||Quercus spp.||<35 |
|northeastern oak-pine||Quercus-Pinus spp.||10 to <35|
|white oak-black oak-northern red oak||Quercus alba-Q. velutina-Q. rubra||<35 |
|canyon live oak||Quercus chrysolepis||<35 to 200|
|blue oak-foothills pine||Quercus douglasii-P. sabiniana||<35 |
|northern pin oak||Quercus ellipsoidalis||<35 |
|Oregon white oak||Quercus garryana||<35 |
|bear oak||Quercus ilicifolia||<35 |
|California black oak||Quercus kelloggii||5-30 |
|bur oak||Quercus macrocarpa||<10 |
|oak savanna||Quercus macrocarpa/Andropogon gerardii-Schizachyrium scoparium||2-14 [121,168]|
|chestnut oak||Quercus prinus||3-8|
|northern red oak||Quercus rubra||10 to <35|
|post oak-blackjack oak||Quercus stellata-Q. marilandica||<10|
|black oak||Quercus velutina||<35 |
|redwood||Sequoia sempervirens||5-200 [11,56,158]|
|western redcedar-western hemlock||Thuja plicata-Tsuga heterophylla||>200 |
|eastern hemlock-yellow birch||Tsuga canadensis-Betula alleghaniensis||100-240 [160,168]|
|eastern hemlock-white pine||Tsuga canadensis-Pinus strobus||x=47 |
|western hemlock-Sitka spruce||Tsuga heterophylla-Picea sitchensis||>200|
|mountain hemlock*||Tsuga mertensiana||35 to >200 |
To the extent that woods strawberry plants can survive fire, or that seedlings can establish in the
postfire environment, it is apparent that fire can have a positive effect on woods strawberry populations. A
review by Patterson and others  indicated that it regenerates from stolons following fire, reaching
preburn levels within 3 to 7 years. Using the nomenclature of Volland and Dell , Powell  rated woods
strawberry postfire response as medium, suggesting it will regain its preburn frequency or cover in 5 to
DISCUSSION AND QUALIFICATION OF PLANT RESPONSE:
While some studies indicate greater abundance of woods strawberry on burned versus unburned plots [113,118], other studies indicate an initial postfire decrease in woods strawberry abundance [104,159] and/or an increase in abundance 3 or more years after fire [2,117,154]. Still others report more equivocal results (e.g., [3,96]). Reported differences may be due to a number of factors, including differences in sampling protocols. For example, some studies compare paired burned and unburned plots at some time after fire, while others compare prefire abundance to postfire abundance over varying numbers of years. Additionally, some studies suggest a correlation between fire severity and woods strawberry response [19,20,82,143], while fire severity estimates are not consistently reported in other studies. It should also be noted that other factors besides fire severity may affect species-specific postfire response. Hypothetically, factors such as the character of the competing vegetation, herbivory, and additional disturbance such as flooding/debris flow may interact with the effects of fire. Interactions between such factors can confound interpretation of postfire data, leading to ambiguous results.
Two studies demonstrate greater woods strawberry presence on burned sites, compared with adjacent unburned habitat. Ten to 11 years after a 1945 wildfire in the Oregon Coast Range, frequency of woods strawberry in burned quadrats was 9%, while none was sampled in unburned forest. The unburned forest was estimated at around 300 years old, composed mainly of Douglas-fir succeeding to western hemlock. Burn characteristics were not well described, although it was apparently a predominantly stand-replacing fire . Similarly, woods strawberry was most prevalent (7% cover; 40% frequency) in a 4-year-old burned stand compared to mature (230 to 320 years old) and second-growth (53 to 80 years old) stands in Douglas-fir-western hemlock/Pacific rhododendron (Rhododendron macrophyllum) communities on the Olympic Peninsula, Washington. Although no details were provided about burn conditions, vegetation data indicate that it was a stand-replacing fire in what was previously mature forest. Woods strawberry was not present in any of the 13 sampled stands of mature forest. It was present but sparse (<1% cover and frequency) in 3 second-growth stands. It was not clear what type of disturbance initiated the second-growth stands .
Other studies show a reduction in woods strawberry in burned plots compared with unburned plots in early postfire years. Three years after the 1979 Ship Island Burn in the Middle Fork Salmon River drainage, central Idaho, woods strawberry cover was significantly (P<0.05) lower in burned plots compared with paired unburned plots . Leege and Godbolt  studied herbaceous response to prescribed burning and grass-seeding treatments to improve elk winter range in shrub-dominated habitat in north-central Idaho. Prescribed burning was conducted in mid-May, and all vegetation sampling took place in July or August. General burn conditions are provided in , but information concerning fire behavior or severity was not. Their data show woods strawberry was less frequent on burned plots than unburned plots.
|Woods strawberry frequency of occurrence within each of ten 2-foot (61 cm) diameter circular measurement plots, 1 year prior to burning and 1, 2, and 4 years after burning (adapted from )|
Woods strawberry populations in postfire plots in these 2 studies may still have been recovering. It is unknown whether woods strawberry frequency increased on these sites in subsequent years.
Some studies indicate that populations of woods strawberry generally remain relatively low in the early postfire environment and begin increasing after 2 or more years [2,117,154]. These studies do not, however, provide information on abundance of woods strawberry before fire or in paired unburned plots. Following the Little Sioux Wildfire in northeastern Minnesota in 1971, vegetation data were collected from seventy 0.605 m² plots each August for 5 years. No other information about the fire was provided .
|Total number of woods strawberry plants sampled each August after a 1971 wildfire in northeastern Minnesota |
Ahlgren  suggested that in forests of the north-central United States and adjacent central Canada, woods strawberry increases gradually for several years following fire, peaking during the 5- to 10-year postfire period, and subsequently declining.
|Average percent cover of woods strawberry in “burned-over jack pine (Pinus banksiana)-black spruce (Picea mariana) forests in northeastern Minnesota at different intervals after fire" (adapted from )|
|Years after fire||1||2||3||4||5||10||15||20||30||50||80|
|Average percent cover (%)||1||2||2||3||4||5||1||1||1||1||1|
Twenty years of woods strawberry cover data were collected each July following the Plant Creek wildfire that burned in late August 1972 in the Sapphire Range, western Montana. These data indicate that woods strawberry was absent for 3 to 17 years following the fire, but eventually established in 9 of 10 study areas. Woods strawberry cover never exceeded 5% on any study area during this time. Prefire data were not provided, so it is not known if these populations were of sprout or seed origin .
|Number of postfire study areas (out of 10 total) containing woods strawberry (adapted from ).|
|Number of study areas||0||0||0||2||2||3||2||4||4||4||4||6||3||5||6||5||5||6||8||7|
Another study showed conflicting results. Postfire response of woods strawberry differed between 2 northern Minnesota mixed conifer-hardwood forest sites. One site was a 10-year-old jack pine plantation burned by wildfire in a late April 1952, and the other site was dominated by jack pine and black spruce and burned by wildfire in July 1955. An unburned mixed conifer-hardwood site, dominated by black spruce, jack pine, and paper birch, served as a contol. Little information about fire behavior or burn conditions was provided, although the authors noted that "little or no soil burn occurred" .
|Woods strawberry percent frequency within thirty 10 m² plots on each site (adapted from )|
|Mixed conifer-hardwood (unburned)||Jack pine (years after burn)||Jack pine-black spruce (years after burn)|
|1956||1965||1954 (3)||1956 (5)||1965 (14)||1956 (2)||1959 (5)||1965 (11)|
Fire severity, particularly fire residence time and magnitude of the downward heat pulse associated with the fire, is likely to impact woods strawberry survival and postfire response. Greater fire severity is associated with increased duff consumption, greater soil heating, and consequently, reduced woods strawberry survival. For example, Hooker and Tisdale  indicated that woods strawberry increased following "low intensity" prescribed fire in a northern Idaho shrubland, but did not "benefit" from "more intense" fire. On shelterwood cutting units in a northern Idaho mixed conifer forest, woods strawberry postfire year 1 cover was slightly lower on a site burned under dry fuel conditions than on a site burned under moist fuel conditions. Differences in fuel moisture between treatments were primarily attributable to duff moisture levels (88% for the moist treatment; 41% for the dry treatment). Average duff consumption was 30% for the moist burn, compared with 90% for the dry burn, indicating higher fire severity on the dry burn site. More detailed burn conditions and fire behavior information are available in .
|Woods strawberry cover during summer just prior to treatment and 1 year after burning (adapted from )|
Following prescribed fires in western Wyoming quaking aspen (Populus tremuloides) communities, woods strawberry biomass decreased with increasing severity 3 years after fire. This pattern was less consistent in postfire year 12 [19,20].
|Woods strawberry production before, 3 years after, and 12 years after fires of varied severitya (adapted from [19,20]). Prefire production was 108 kg/ha.|
|Years after fire||3||12|
|Light||94 kg/ha||75 kg/ha|
|Moderate||78 kg/ha||14 kg/ha|
|Heavy||51 kg/ha||45 kg/ha|
a Light burns indicate an estimated 0% to 20% of litter and duff consumed
Moderate burns indicate an estimated 20% to 80% of litter and duff consumed
Heavy burns indicate an estimated 81% to 100% of litter and duff consumed
Further evidence linking fire severity with woods strawberry's postfire response is provided by Wang and Kimball , who examined vegetation response following a wildfire in a boreal mixedwood forest codominated by quaking aspen and a mixture of balsam fir (Abies balsamea), white spruce (Picea glauca), black spruce and/or jack pine.
|Average woods strawberry cover and frequency over 4 postfire years |
aScorched indicates litter not burned or partially burned
bLightly burned indicates litter burned but with little to no duff consumption
cSeverely burned indicates forest floor completely consumed; organic matter in upper mineral soil horizon may also be partially consumed
Two northern Minnesota studies also indicate a stronger woods strawberry postfire response when fire is less severe. At 2 jack pine forest sites that were logged and then burned 1 year later, frequency of woods strawberry was similar before cutting and burning (80-83%) but differed between sites after treatment. Differences in fire severity might explain lower frequency of woods strawberry at the Grass Lake site (3-13%, 1-2 years after fire) compared with the East Bearskin Lake site (57-83%, 1-2 years after fire). Temperatures reached at the soil surface were, on average, greater than 900° F (480° C) at the Grass Lake site and less than that at the East Bearskin Lake site . In another northern Minnesota study conducted in several forest types, woods strawberry frequency tended to be higher on burned versus unburned plots, although frequency was lower on a severe burn versus a burn of moderate severity at one site . Lack of prefire information and mixed sampling approaches among sites make results from this study difficult to interpret.
On ponderosa pine and Douglas-fir communities in the Blue Mountains of northeastern Oregon, woods strawberry cover and frequency were higher on unburned control sites than on prescribed burned, thinned, or thinned-and-burned sites. Woods strawberry was determined to be an indicator species for unburned sites (P≤0.05). For further information on the effects of thinning and burning treatments on woods strawberry and 48 other species, see the Research Project Summary of Youngblood and others'  study.
These fire studies also provide information on postfire responses of plant species in communities that include woods strawberry:
It has been suggested that woods strawberry might be an important species for mitigating postfire erosion potential. From observations of postfire shrubfields in northern Idaho, Hooker and Tisdale  wrote that woods strawberry "appeared to have an important stabilizing influence on the surface soils of the steeper slopes, since it was abundant after burning and sent out numerous stolons."
Tame mule deer utilized woods strawberry in Utah and Colorado. In a lodgepole pine-dominated forest area in northeastern Utah, woods strawberry constituted 5% by weight of the summer diet of tame mule deer in clearcut forest and mature forest habitats . Tame mule deer utilized small amounts of woods strawberry in lodgepole pine and Englemann spruce (Picea engelmannii)-subalpine fir (Abies lasiocarpa) habitats in central Colorado in summer . In an experiment on a central Colorado ponderosa pine/bunchgrass range, observations of grazing preferences of tame mule deer indicated that woods strawberry was among preferred food species. Average percent of mule deer diet comprised of woods strawberry was as follows :
|Average monthly use||April||May||June||July||August||October|
Woods strawberry is also eaten by other native mammals, including grizzly bears , black bears [150,151], and raccoons , although it is unclear if these animals are eating strictly fruit, or if they are also utilizing foliage.
Fruits are eaten by grouse and songbirds [83,150,151]. Wild strawberry is "perhaps the most important herbaceous food plant for" ruffed grouse in Minnesota . Hungerford  suggested that it was an important food for ruffed grouse in Idaho.
Palatability/nutritional value: According to Steele and Geier-Hayes [150,151] woods strawberry is moderately palatable to deer, elk and sheep. Its leaves remain "green through the winter" and provide a higher forage value "than most herb layer species during that season."
Cover value: No information is available on this topic.VALUE FOR REHABILITATION OF DISTURBED SITES:
OTHER MANAGEMENT CONSIDERATIONS:
Published information provides conflicting evidence concerning woods strawberry grazing tolerance. Hall  reported that wild strawberries tended to increase with overgrazing in the Blue Mountains of eastern Oregon and southeastern Washington. Steele and Geier-Hayes [147,148,149] indicated that, on "cutover" sites in grand fir- and Douglas-fir-dominated habitat types in Idaho, woods strawberry was less tolerant of heavy grazing than either Virginia strawberry or other common grazing-tolerant forbs. It was also suggested that woods strawberry is susceptible to trampling from heavy livestock traffic [147,148,149]. In northern California, Saenz  recorded the presence of woods strawberry in "lightly" grazed (only grazed "late in the season" by cattle) Oregon white oak woodland, but it was not observed in "heavily" grazed (grazed by cattle "for as much of the year as weather permitted") woodland, nor in "lightly" grazed or "heavily" grazed grassland.
In meadow habitat surrounded by ponderosa pine (Pinus ponderosa) forest on the Mogollon Rim, northern Arizona, exclusion of grazing by cattle, elk and deer had no consistent effect on relative abundance of woods strawberry. Comparisons were made between grazed plots and fenced exclosure plots where there had been no grazing for 8 to 9 years. Woods strawberry "relative abundance (%)" ranged from 0 to 6.5%, with no discernable effect of grazing among 3 sites.
A study on the Rogue River National Forest, Oregon, suggests that on logged sites where woods strawberry is present, removing slash (in this case piling and burning) results in greater woods strawberry presence, compared with leaving slash in place .Limited evidence suggests that woods strawberry may be relatively resistant to some herbicides. Rice and Toney  studied the effects of herbicide treatments for controlling spotted knapweed (Centaurea maculosa) on native forest and grassland vegetation in west-central Montana. At a single site, woods strawberry occurrence was not significantly (P=0.67) different in untreated plots and plots treated once with either picloram or clopyralid . It also does not appear particularly susceptible to glyphosate . Caution should be observed when making assumptions about effects of specific herbicides, application rates, and repeated applications on woods strawberry.
1. Agee, James K. 1994. Fire and weather disturbances in terrestrial ecosystems of the eastern Cascades. Gen. Tech. Rep. PNW-GTR-320. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 52 p. [Hessburg, Paul F., tech. ed. Eastside forest ecosystem health assessment. Vol. 3: assessment]. 
2. Ahlgren, C. E. 1974. Effects of fires on temperate forests: north central United States. In: Kozlowski, T. T.; Ahlgren, C. E., eds. Fire and ecosystems. New York: Academic Press: 195-223. 
3. Ahlgren, Clifford E. 1960. Some effects of fire on reproduction and growth of vegetation in northeastern Minnesota. Ecology. 41(3): 431-445. 
4. Ahlgren, Clifford E. 1966. Small mammals and reforestation following prescribed burning. Journal of Forestry. 64: 614-618. 
5. Alexander, Billy G., Jr.; Fitzhugh, E. Lee; Ronco, Frank, Jr.; Ludwig, John A. 1987. A classification of forest habitat types of the northern portion of the Cibola National Forest, New Mexico. Gen. Tech. Rep. RM-143. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 35 p. 
6. Angevine, Mark A. 1983. Variations in the demography of natural populations of the wild strawberries Fragaria vesca and Fragaria virginiana. Journal of Ecology. 71(3): 959-974. 
7. Antos, J. A.; Habeck, J. R. 1981. Successional development in Abies grandis (Dougl.) Forbes forests in the Swan Valley, western Montana. Northwest Science. 55(1): 26-39. 
8. Aplet, G. H.; Anderson, S. J.; Stone, C. P. 1991. Association between feral pig disturbance and the composition of some alien plant assemblages in Hawaii Volcanoes National Park. Vegetatio. 95: 55-62. 
9. Arno, Stephen F. 1976. The historical role of fire on the Bitterroot National Forest. Res. Pap. INT-187. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 29 p. 
10. Arno, Stephen F. 1980. Forest fire history in the Northern Rockies. Journal of Forestry. 78(8): 460-465. 
11. Arno, Stephen F. 2000. Fire in western forest ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 97-120. 
12. Arno, Stephen F.; Fischer, William C. 1995. Larix occidentalis--fire ecology and fire management. In: Schmidt, Wyman C.; McDonald, Kathy J., comps. Ecology and management of Larix forests: a look ahead: Proceedings of an international symposium; 1992 October 5-9; Whitefish, MT. Gen. Tech. Rep. GTR-INT-319. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 130-135. 
13. Arno, Stephen F.; Gruell, George E. 1983. Fire history at the forest-grassland ecotone in southwestern Montana. Journal of Range Management. 36(3): 332-336. 
14. Arno, Stephen F.; Scott, Joe H.; Hartwell, Michael G. 1995. Age-class structure of old growth ponderosa pine/Douglas-fir stands and its relationship to fire history. Res. Pap. INT-RP-481. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 25 p. 
15. Atzet, Thomas; McCrimmon, Lisa A. 1990. Preliminary plant associations of the southern Oregon Cascade Mountain province. Grants Pass, OR: U.S. Department of Agriculture, Forest Service, Siskiyou National Forest. 330 p. 
16. Baisan, Christopher H.; Swetnam, Thomas W. 1990. Fire history on a desert mountain range: Rincon Mountain Wilderness, Arizona, U.S.A. Canadian Journal of Forest Research. 20: 1559-1569. 
17. Barrett, Stephen W. 1993. Fire regimes on the Clearwater and Nez Perce National Forests north-central Idaho. Final Report: Order No. 43-0276-3-0112. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Fire Sciences Laboratory. Unpublished report on file with: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, Missoula, MT. 21 p. 
18. Barrett, Stephen W.; Arno, Stephen F.; Key, Carl H. 1991. Fire regimes of western larch - lodgepole pine forests in Glacier National Park, Montana. Canadian Journal of Forest Research. 21: 1711-1720. 
19. Bartos, D. L.; Mueggler, W. F. 1981. Early succession in aspen communities following fire in western Wyoming. Journal of Range Management. 34(4): 315-318. 
20. Bartos, Dale L.; Brown, James K.; Booth, Gordon D. 1994. Twelve years biomass response in aspen communities following fire. Journal of Range Management. 47: 79-83. 
21. Bernard, Stephen R.; Brown, Kenneth F. 1977. Distribution of mammals, reptiles, and amphibians by BLM physiographic regions and A.W. Kuchler's associations for the eleven western states. Tech. Note 301. Denver, CO: U.S. Department of the Interior, Bureau of Land Management. 169 p. 
22. Bierzychudek, Paulette. 1982. Life histories and demography of shade-tolerant temperate forest herbs: a review. New Phytologist. 90: 757-776. 
23. Bingham, Richard T. 1987. Plants of the Seven Devils Mountains of Idaho--an annotated checklist. General Technical Report INT-219. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 146 p. 
24. Biring, B. S.; Hays-Byl, W. J.; Hoyles, S. E. 1999. Twelve-year conifer and vegetation responses to discing and glyphosate treatments on a BWBSmw backlog site. Working Paper 43. Victoria, BC: British Columbia Ministry of Forests, Research Branch. 34 p. 
25. Blatt, S. E.; Crowder, A.; Harmsen, R. 2005. Secondary succession in two south-eastern Ontario old-fields. Plant Ecology. 177: 25-41. 
26. Boltz, Michael John. 1979. Impacts of prescribed burns and clearcuts upon summer elk food habits, diet quality, and distribution in central Washington. Pullman, WA: Washington State University. 129 p. Thesis. 
27. Booth, W. E.; Wright, J. C. 1962. [Revised]. Flora of Montana: Part II--Dicotyledons. Bozeman, MT: Montana State College, Department of Botany and Bacteriology. 280 p. 
28. Bowers, Janice E.; McLaughlin, Steven P. 1987. Flora and vegetation of the Rincon Mountains, Pima County, Arizona. Desert Plants. 8(2): 50-94. 
29. Brown, James K.; DeByle, Norbert V. 1989. Effects of prescribed fire on biomass and plant succession in western aspen. Res. Pap. INT-412. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 16 p. 
30. Buchholz, Kenneth; Good, Ralph E. 1982. Density, age structure, biomass and net annual aboveground productivity of dwarfed Pinus rigida Moll. from the New Jersey Pine Barren Plains. Bulletin of the Torrey Botanical Club. 109(1): 24-34. 
31. Campbell, Erick G.; Johnson, Rolf L. 1983. Food habits of mountain goats, mule deer, and cattle on Chopaka Mountain, Washington, 1977-1980. Journal of Range Management. 36(4): 488-491. 
32. Chesnut, V. K. 1902. Plants used by the Indians of Mendocino County, California. Contributions from the U.S. National Herbarium. [Washington, DC]: U.S. Department of Agriculture, Division of Botany. 7(3): 295-408. 
33. Clark, James S. 1990. Fire and climate change during the last 750 yr in northwestern Minnesota. Ecological Monographs. 60(2): 135-159. 
34. Cleland, David T.; Crow, Thomas R.; Saunders, Sari C.; Dickmann, Donald I.; Maclean, Ann L.; Jordan, James K.; Watson, Richard L.; Sloan, Alyssa M.; Brosofske, Kimberley D. 2004. Characterizing historical and modern fire regimes in Michigan (USA): a landscape ecosystem approach. Landscape Ecology. 19: 311-325. 
35. Cooper, Charles F. 1960. Changes in vegetation, structure, and growth of southwestern pine forests since white settlement. Ecological Monographs. 30(2): 129-164. 
36. Core, Earl L. 1929. Plant ecology of Spruce Mountain, West Virginia. Ecology. 10(1): 1-13. 
37. Cronquist, Arthur; Holmgren, Noel H.; Holmgren, Patricia K. 1997. Intermountain flora: Vascular plants of the Intermountain West, U.S.A. Vol. 3, Part A: Subclass Rosidae (except Fabales). New York: The New York Botanical Garden. 446 p. 
38. Crouch, Glenn L. 1985. Effects of clearcutting a subalpine forest in central Colorado on wildlife habitat. Res. Pap. RM-258. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 12 p. 
39. Crouch, Glenn L. 1986. Effects of thinning pole-sized lodgepole pine on understory vegetation and large herbivore activity in central Colorado. Res. Pap. RM-268. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 10 p. 
40. Currie, P. O.; Reichert, D. W.; Malechek, J. C.; Wallmo, O. C. 1977. Forage selection comparisons for mule deer and cattle under managed ponderosa pine. Journal of Range Management. 30(5): 352-356. 
41. Davis, Dan; Butterfield, Bart. 1991. The Bitterroot Grizzly Bear Evaluation Area: A report to the Bitterroot Technical Review Team. Unpublished report on file with: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, Missoula, MT. 56 p. 
42. Davis, Kathleen M. 1980. Fire history of a western larch/Douglas-fir forest type in northwestern Montana. In: Stokes, Marvin A.; Dieterich, John H., tech. coords. Proceedings of the fire history workshop; 1980 October 20-24; Tucson, AZ. Gen. Tech. Rep. RM-81. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 69-74. 
43. Deschamp, Joseph A.; Urness, Philip J.; Austin, Dennis D. 1979. Summer diets of mule deer from lodgepole pine habitats. Journal of Wildlife Management. 43(1): 154-161. 
44. Despain, Don G. 1990. Yellowstone vegetation: Consequences of environment and history in a natural setting. Boulder, CO: Roberts Rinehart, Inc. 239 p. 
45. Donnegan, Joseph A. 1999. Climatic and human influences on fire regimes in Pike National Forest. Boulder, CO: University of Colorado. 122 p. Dissertation. 
46. Donnegan, Joseph A.; Veblen, Thomas T.; Sibold, Jason S. 2001. Climatic and human influences on fire history in Pike National Forest, central Colorado. Canadian Journal of Forest Research. 31: 1526-1539. 
47. Dorn, Robert D. 1977. Flora of the Black Hills. Cheyenne, WY: Robert D. Dorn and Jane L. Dorn. 377 p. 
48. Dorn, Robert D. 1984. Vascular plants of Montana. Cheyenne, WY: Mountain West Publishing. 276 p. 
49. Dorn, Robert D. 1988. Vascular plants of Wyoming. Cheyenne, WY: Mountain West Publishing. 340 p. 
50. Duchesne, Luc C.; Hawkes, Brad C. 2000. Fire in northern ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 35-51. 
51. Duncan, Wilbur H.; Duncan, Marion B. 1987. The Smithsonian guide to seaside plants of the Gulf and Atlantic coasts from Louisiana to Massachusetts, exclusive of lower peninsular Florida. Washington, DC: Smithsonian Institution Press. 409 p. 
52. Eggler, Willis A. 1980. Live oak. In: Eyre, F. H., ed. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters: 63-64. 
53. Eriksson, O. 1989. Seedling dynamics and life histories in clonal plants. Oikos. 55: 231-238. 
54. Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. 
55. Ferguson, Dennis E.; Byrne, John C.; Coffen, Dale O. 2005. Reforestation trials and secondary succession with three levels of overstory shade in the Grand Fir Mosaic ecosystem. Res. Pap. RMRS-RP-53. Fort Collins, CO: U. S. Department of Agriculture, Forest Service, Rocky Moutain Research Station. 16 p. 
56. Finney, Mark A.; Martin, Robert E. 1989. Fire history in a Sequoia sempervirens forest at Salt Point State Park, California. Canadian Journal of Forest Research. 19: 1451-1457. 
57. Franklin, Jerry F.; Dyrness, C. T. 1973. Natural vegetation of Oregon and Washington. Gen. Tech. Rep. PNW-8. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 417 p. 
58. Frissell, Sidney S., Jr. 1968. A fire chronology for Itasca State Park, Minnesota. Minnesota Forestry Research Notes No. 196. Minneapolis, MN: University of Minnesota. 2 p. 
59. Gardner, Shelley L. 1999. Community classification in the ponderosa pine, mixed conifer, and spruce-fir zones of the east side of the Jemez Mountains, New Mexico. Nacogdoches, TX: Stephen F. Austin State University. 105 p. Thesis. 
60. Garrison, George A.; Bjugstad, Ardell J.; Duncan, Don A.; Lewis, Mont E.; Smith, Dixie R. 1977. Vegetation and environmental features of forest and range ecosystems. Agric. Handb. 475. Washington, DC: U.S. Department of Agriculture, Forest Service. 68 p. 
61. Gleason, Henry A.; Cronquist, Arthur. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. 2nd ed. New York: New York Botanical Garden. 910 p. 
62. Goodrich, Sherel; Neese, Elizabeth. 1986. Uinta Basin flora. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Region, Ashley National Forest; Vernal, UT: U.S. Department of the Interior, Bureau of Land Management, Vernal District. 320 p. 
63. Great Plains Flora Association. 1986. Flora of the Great Plains. Lawrence, KS: University Press of Kansas. 1392 p. 
64. Green, Pat; Jensen, Mark. 1991. Plant succession within managed grand fir forests of northern Idaho. In: Harvey, Alan E.; Neuenschwander, Leon F., compilers. Proceedings--management and productivity of western-montane forest soils; 1990 April 10-12; Boise, ID. Gen. Tech. Rep. INT-280. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 232-236. 
65. Grigal, D. F.; Ohmann, Lewis F. 1975. Classification, description, and dynamics of upland plant communities within a Minnesota wilderness area. Ecological Monographs. 45(4): 389-407. 
66. Gruell, G. E.; Loope, L. L. 1974. Relationships among aspen, fire, and ungulate browsing in Jackson Hole, Wyoming. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 33 p. In cooperation with: U.S. Department of the Interior, National Park Service, Rocky Mountain Region. 
67. Gullion, Gordon W. 1968. Recommendations for management of ruffed grouse habitat in northern Minnesota. Information Leaflet No. 100. St. Paul, MN: Minnesota Division of Game and Fish.3 p. 
68. Guyette, Richard; McGinnes, E. A., Jr. 1982. Fire history of an Ozark glade in Missouri. Transactions, Missouri Academy of Science. 16: 85-93. 
69. Habeck, James R. 1970. Fire ecology investigations in Glacier National Park: Historical considerations and current observations. Missoula, MT: University of Montana, Department of Botany. 80 p. 
70. Hall, Frederick C. 1973. Plant communities of the Blue Mountains in eastern Oregon and southeastern Washington. R6 Area Guide 3-1. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Region. 82 p. 
71. Halpern, Charles B.; Harmon, Mark E. 1983. Early plant succession on the Muddy River mudflow, Mount St. Helens, Washington. The American Midland Naturalist. 110(1): 97-106. 
72. Halverson, Nancy M., comp. 1986. Major indicator shrubs and herbs on national forests of western Oregon and southwestern Washington. R6-TM-229. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Region. 180 p. 
73. Harrington, H. D. 1964. Manual of the plants of Colorado. 2nd ed. Chicago, IL: The Swallow Press, Inc. 666 p. 
74. Harrison, A. Tyrone. 1980. The Niobrara Valley Preserve: its biogeographic importance and description of its biotic communities. A working report to the Nature Conservancy. 116 p. On file with: U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Fire Sciences Laboratory, Missoula, MT. 
75. Heinselman, Miron L. 1970. The natural role of fire in northern conifer forests. In: The role of fire in the Intermountain West: Symposium proceedings; 1970 October 27-29; Missoula, MT. Missoula, MT: Intermountain Fire Research Council: 30-41. In cooperation with: University of Montana, School of Forestry. 
76. Hendrickson, William H. 1972. Perspective on fire and ecosystems in the United States. In: Fire in the environment: Symposium proceedings; 1972 May 1-5; Denver, CO. FS-276. [Washington, DC]: U.S. Department of Agriculture, Forest Service: 29-33. In cooperation with: Fire Services of Canada, Mexico, and the United States; Members of the Fire Management Study Group; North American Forestry Commission; FAO. 
77. Hess, Karl; Wasser, Clinton H. 1982. Grassland, shrubland, and forestland habitat types of the White River-Arapaho National Forest. Final Report. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 335 p. 
78. Hickman, James C., ed. 1993. The Jepson manual: Higher plants of California. Berkeley, CA: University of California Press. 1400 p. 
79. Hitchcock, C. Leo; Cronquist, Arthur. 1973. Flora of the Pacific Northwest. Seattle, WA: University of Washington Press. 730 p. 
80. Hitchcock, C. Leo; Cronquist, Arthur; Ownbey, Marion; Thompson, J. W. 1961. Vascular plants of the Pacific Northwest. Part 3: Saxifragaceae to Ericaceae. Seattle, WA: University of Washington Press. 614 p. 
81. Holmgren, Arthur H.; Reveal, James L. 1966. Checklist of the vascular plants of the Intermountain Region. Res. Pap. INT-32. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 160 p. 
82. Hooker, Larry L.; Tisdale, E. W. 1974. Effects of prescribed burning on a seral brush community in northern Idaho. Station Paper No. 14. Moscow, ID: University of Idaho, Forest, Wildlife and Range Experiment Station. 11 p. 
83. Hungerford, Kenneth E. 1957. Evaluating ruffed grouse foods for habitat improvement. Transactions, 22nd North American Wildlife Conference. [Volume unknown]: 380-395. 
84. Johnson, Charles G., Jr.; Simon, Steven A. 1987. Plant associations of the Wallowa-Snake Province: Wallowa-Whitman National Forest. R6-ECOL-TP-255A-86. Baker, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Region, Wallowa-Whitman National Forest. 399 p. 
85. Johnson, Charles Grier, Jr. 1998. Vegetation response after wildfires in national forests of northeastern Oregon. R6-NR-ECOL-TP-06-98. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Region. 128 p. plus appendices. 
86. Johnston, Marshall C. 1979. The Guadalupe Mountains--a chink in the mosaic of the Chihuahuan Desert? In: Genoways, Hugh H.; Baker, Robert J., eds. Biological investigations in the Guadalupe Mountains National Park: Proceedings of a symposium; 1975 April 4-5; Lubbock, TX. Proceedings and Transactions Series No. 4. Washington, DC: U.S. Department of the Interior, National Park Service: 45-49. 
87. Jones, Stanley D.; Wipff, Joseph K.; Montgomery, Paul M. 1997. Vascular plants of Texas. Austin, TX: University of Texas Press. 404 p. 
88. Jurik, Thomas W. 1985. Differential costs of sexual and vegetative reproduction in wild strawberry populations. Oecologia. 66: 394-403. 
89. Kartesz, John T. 1999. A synonymized checklist and atlas with biological attributes for the vascular flora of the United States, Canada, and Greenland. 1st ed. In: Kartesz, John T.; Meacham, Christopher A. Synthesis of the North American flora (Windows Version 1.0), [CD-ROM]. Chapel Hill, NC: North Carolina Botanical Garden (Producer). In cooperation with: The Nature Conservancy; U.S. Department of Agriculture, Natural Resources Conservation Service; U.S. Department of the Interior, Fish and Wildlife Service. 
90. Kearney, Thomas H.; Peebles, Robert H.; Howell, John Thomas; McClintock, Elizabeth. 1960. Arizona flora. 2nd ed. Berkeley, CA: University of California Press. 1085 p. 
91. Kemball, Kevin J.; Wang, G. Geoff; Dang, Qing-Lai. 2005. Response of understory plant community of boreal mixedwood stands to fire, logging, and spruce budworm outbreak. Canadian Journal of Botany. 83(12): 1550-1560. 
92. Kingery, James L.; Mosley, Jeffrey C.; Bordwell, Kirsten C. 1996. Dietary overlap among cattle and cervids in northern Idaho forests. Journal of Range Management. 49(1): 8-15. 
93. Knight, Dennis H.; Anderson, A. Duane; Baxter, George T.; Diem, Kenneth L.; Parker, Michael; Rechard, Paul A.; Singleton, Paul C.; Thilenius, John F.; Ward, A. Lorin; Weeks, Richard W. 1975. The Medicine Bow Ecology Project. Final report: Contract No. 14-06-D-7198. Laramie, WY: The University of Wyoming. 397 p. In cooperation with: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station; Wyoming Water Resources Research Institute. 
94. Kramer, Neal B.; Johnson, Frederic D. 1987. Mature forest seed banks of three habitat types in central Idaho. Canadian Journal of Botany. 65: 1961-1966. 
95. Kranz, Jeremiah J.; Linder, Raymond L. 1973. Value of Black Hills forest communities to deer and cattle. Journal of Range Management. 26(4): 263-265. 
96. Krefting, Laurits W.; Ahlgren, Clifford E. 1974. Small mammals and vegetation changes after fire in a mixed conifer-hardwood forest. Ecology. 55: 1391-1398. 
97. Kuchler, A. W. 1964. Manual to accompany the map of potential vegetation of the conterminous United States. Special Publication No. 36. New York: American Geographical Society. 77 p. 
98. Lackschewitz, Klaus. 1986. Plants of west-central Montana--identification and ecology: annotated checklist. Gen. Tech. Rep. INT-217. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 128 p. 
99. Lackschewitz, Klaus. 1991. Vascular plants of west-central Montana--identification guidebook. Gen. Tech. Rep. INT-227. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 648 p. 
100. Langenheim, Jean H. 1962. Vegetation and environmental patterns in the Crested Butte area, Gunnison County, Colorado. Ecological Monographs. 32(2): 249-285. 
101. Laven, R. D.; Omi, P. N.; Wyant, J. G.; Pinkerton, A. S. 1980. Interpretation of fire scar data from a ponderosa pine ecosystem in the central Rocky Mountains, Colorado. In: Stokes, Marvin A.; Dieterich, John H., tech. coords. Proceedings of the fire history workshop; 1980 October 20-24; Tucson, AZ. Gen. Tech. Rep. RM-81. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 46-49. 
102. Layser, Earle F. 1980. Flora of Pend Oreille County, Washington. Pullman, WA: Washington State University, Cooperative Extension. 146 p. 
103. Leege, Thomas A., compiler. 1984. Guidelines for evaluating and managing summer elk habitat in northern Idaho. Wildlife Bull. No. 11; Federal Aid Project W-160-R. Boise, ID: Idaho Fish and Game Department. 37 p. 
104. Leege, Thomas A.; Godbolt, Grant. 1985. Herbaceous response following prescribed burning and seeding of elk range in Idaho. Northwest Science. 59(2): 134-143. 
105. Lepofsky, Dana; Turner, Nancy J.; Kuhnlein, Harriet V. 1985. Determining the availability of traditional wild plant foods: an example of Nuxalk foods, Bella Coola, British Columbia. Ecology of Food and Nutrition. 16: 223-241. 
106. Loope, Walter L. 1991. Interrelationships of fire history, land use history, and landscape pattern within Pictured Rocks National Seashore, Michigan. The Canadian Field-Naturalist. 105(1): 18-28. 
107. Maini, Jagmohan Singh. 1960. Invasion of grassland by Populus tremuloides in the northern Great Plains. Saskatoon, SK: University of Saskatchewan. 213 p. Thesis. 
108. Martin, William C.; Hutchins, Charles R. 1981. A flora of New Mexico. Volume 2. Germany: J. Cramer. 2589 p. 
109. McIntire, Patrick W. 1984. Fungus consumption by the Siskiyou chipmunk within a variously treated forest. Ecology. 65(1): 137-146. 
110. Meinecke, E. P. 1929. Quaking aspen: A study in applied forest pathology. Tech. Bull. No. 155. Washington, DC: U.S. Department of Agriculture. 34 p. 
111. Mohlenbrock, Robert H. 1986. [Revised edition]. Guide to the vascular flora of Illinois. Carbondale, IL: Southern Illinois University Press. 507 p. 
112. Morrison, Peter H.; Swanson, Frederick J. 1990. Fire history and pattern in a Cascade Range landscape. Gen. Tech. Rep. PNW-GTR-254. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 77 p. 
113. Neiland, Bonita J. 1958. Forest and adjacent burn in the Tillamook Burn area of northwestern Oregon. Ecology. 39(4): 660-671. 
114. Nelson, Cara R.; Halpern, Charles B. 2005. Edge-related responses of understory plants to aggregated retention harvest in the Pacific Northwest. Ecological Applications. 15(1): 196-209. 
115. Nichols, G. E. 1934. The influence of exposure to winter temperatures upon seed germination in various native American plants. Ecology. 15(4): 364-373. 
116. Odum, Eugene P. 1943. The vegetation of the Edmund Niles Huyck Preserve, New York. American Midland Naturalist. 29(1): 72-88. 
117. Ohmann, Lewis F.; Grigal, David F. 1977. Some individual plant biomass values from northeastern Minnesota. Res. Note NC-227. St. Paul, MN: U.S. Department of Agriculture, Forest Service, North Central Forest Experiment Station. 2 p. 
118. Ossinger, Mary C. 1983. The Pseudotsuga-Tsuga/Rhododendron community in the northeast Olympic Mountains. Bellingham, WA: Western Washington University. 50 p. Thesis. 
119. Ostler, W. Kent; Harper, K. T. 1978. Floral ecology in relation to plant species diversity in the Wasatch Mountains of Utah and Idaho. Ecology. 59(4): 848-861. 
120. Patterson, Patricia A.; Neiman, Kenneth E.; Tonn, Jonalea. 1985. Field guide to forest plants of northern Idaho. Gen. Tech. Rep. INT-180. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 246 p. 
121. Paysen, Timothy E.; Ansley, R. James; Brown, James K.; Gottfried, Gerald J.; Haase, Sally M.; Harrington, Michael G.; Narog, Marcia G.; Sackett, Stephen S.; Wilson, Ruth C. 2000. Fire in western shrubland, woodland, and grassland ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 121-159. 
122. Pojar, Jim; MacKinnon, Andy, eds. 1994. Plants of the Pacific Northwest coast: Washington, Oregon, British Columbia and Alaska. Redmond, WA: Lone Pine Publishing. 526 p. 
123. Popovich, Steve J.; Shepperd, Wayne D.; Reichert, Donald W.; Cone, Michael A. 1993. Flora of the Fraser Experimental Forest, Colorado. Gen. Tech. Rep. RM-233. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 62 p. 
124. Powell, David C. 1994. Effects of the 1980's western spruce budworm outbreak on the Malheur National Forest in northeastern Oregon. Tech. Pub. R6-FI&D-TP-12-94. Portland, OR: U.S. Department of Agriculture, Forest Service, Natural Resources Staff, Forest Insects and Diseases Group. 176 p. 
125. Qi, Meiqin; Scarratt, John B. 1998. Effect of harvesting method on seed bank dynamics in a boreal mixedwood forest in northwestern Ontario. Canadian Journal of Botany. 76: 872-883. 
126. Radford, Albert E.; Ahles, Harry E.; Bell, C. Ritchie. 1968. Manual of the vascular flora of the Carolinas. Chapel Hill, NC: The University of North Carolina Press. 1183 p. 
127. Rambo, Jennie L.; Faeth, Stanley H. 1999. Effect of vertebrate grazing on plant and insect community structure. Conservation Biology. 13(5): 1047-1054. 
128. Raunkiaer, C. 1934. The life forms of plants and statistical plant geography. Oxford: Clarendon Press. 632 p. 
129. Reed, John F. 1952. The vegetation of the Jackson Hole Wildlife Park, Wyoming. The American Midland Naturalist. 48(3): 700-729. 
130. Rice, P. M.; Toney, J. C. 1996. Plant population responses to broadcast herbicide applications for spotted knapweed control. Down to Earth. 51(2): 14-19. 
131. Ripple, William J. 1994. Historic spatial patterns of old forests in western Oregon. Journal of Forestry. 92(11): 45-49. 
132. Rivest, Pierre; Bergeron, Jean-Marie. 1981. Density, food habits, and economic importance of raccoons (Procyon lotor) in Quebec agrosystems. Canadian Journal of Zoology. 59: 1755-1762. 
133. Roberts, Mark R.; Zhu, Lixiang. 2002. Early response of the herbaecous layer to harvesting in a mixed coniferous-deciduous forest in New Brunswick, Canada. Forest Ecology and Management. 155: 17-31. 
134. Roland, A. E.; Smith, E. C. 1969. The flora of Nova Scotia. Halifax, NS: Nova Scotia Museum. 746 p. 
135. Ross, Robert L.; Hunter, Harold E. 1976. Climax vegetation of Montana: Based on soils and climate. Bozeman, MT: U.S. Department of Agriculture, Soil Conservation Service. 64 p. 
136. Rowe, J. S. 1983. Concepts of fire effects on plant individuals and species. In: Wein, Ross W.; MacLean, David A., eds. The role of fire in northern circumpolar ecosystems. SCOPE 18. New York: John Wiley & Sons: 135-154. 
137. Rundel, Philip W.; Parsons, David J.; Gordon, Donald T. 1977. Montane and subalpine vegetation of the Sierra Nevada and Cascade Ranges. In: Barbour, Michael G.; Major, Jack, eds. Terrestrial vegetation of California. New York: John Wiley & Sons: 559-599. 
138. Saenz, Loretta. 1983. Quercus garryana woodland/grassland mosaic dynamics in northern California. Arcata, CA: Humboldt State University. 71 p. Thesis. 
139. Schmidt, Wyman C.; Lotan, James E. 1980. Phenology of common forest flora of the northern Rockies--1928 to 1937. Res. Pap. INT-259. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 20 p. 
140. Seklecki, Mariette T.; Grissino-Mayer, Henri D.; Swetnam, Thomas W. 1996. Fire history and the possible role of Apache-set fires in the Chiricahua Mountains of southeastern Arizona. In: Ffolliott, Peter F.; DeBano, Leonard F.; Baker, Malchus B., Jr.; Gottfried, Gerald J.; Solis-Garza, Gilberto; Edminster, Carleton B.; Neary, Daniel G.; Allen, Larry S.; Hamre, R. H., tech. coords. Effects of fire on Madrean Province ecosystems: a symposium proceedings; 1996 March 11-15; Tucson, AZ. Gen. Tech. Rep. RM-GTR-289. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 238-246. 
141. Seymour, Frank Conkling. 1982. The flora of New England. 2nd ed. Phytologia Memoirs 5. Plainfield, NJ: Harold N. Moldenke and Alma L. Moldenke. 611 p. 
142. Shiflet, Thomas N., ed. 1994. Rangeland cover types of the United States. Denver, CO: Society for Range Management. 152 p. 
143. Simmerman, Dennis G.; Arno, Stephen F.; Harrington, Michael G.; Graham, Russell T. 1991. A comparison of dry and moist fuel underburns in ponderosa pine shelterwood units in Idaho. In: Andrews, Patricia L.; Potts, Donald F., eds. Proceedings, 11th annual conference on fire and forest meteorology; 1991 April 16-19; Missoula, MT. SAF Publication 91-04. Bethesda, MD: Society of American Foresters: 387-397. 
144. Spies, Thomas A. 1991. Plant species diversity and occurrence in young, mature, and old-growth Douglas-fir stands in western Oregon and Washington. In: Ruggiero, Leonard F.; Aubry, Keith B.; Carey, Andrew B.; Huff, Mark H., technical coordinators. Wildlife and vegetation of unmanaged Douglas-fir forests. Gen. Tech. Rep. PNW-GTR-285. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station: 111-121. 
145. Standley, Paul C. 1921. Flora of Glacier National Park, Montana. Contributions from the United States National Herbarium. Vol. 22, Part 5. Washington, DC: United States National Museum, Smithsonian Institution: 235-438. 
146. Staudt, G. 1989. The species of Fragaria, their taxonomy and geographical distribution. Acta Horticulturae. 265: 23-33. 
147. Steele, Robert; Geier-Hayes, Kathleen. 1987. The grand fir/blue huckleberry habitat type in central Idaho: succession and management. Gen. Tech. Rep. INT-228. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 66 p. 
148. Steele, Robert; Geier-Hayes, Kathleen. 1989. The Douglas-fir/mountain maple habitat type in central Idaho: succession and management. Preliminary draft. On file at: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, Missoula, MT. 77 p. 
149. Steele, Robert; Geier-Hayes, Kathleen. 1989. The Douglas-fir/ninebark habitat type in central Idaho: succession and management. Gen. Tech. Rep. INT-252. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 65 p. 
150. Steele, Robert; Geier-Hayes, Kathleen. 1989. The grand fir/mountain maple habitat type in central Idaho: succession and management. Review draft. On file at: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, Missoula, MT. 148 p. 
151. Steele, Robert; Geier-Hayes, Kathleen. 1994. The Douglas-fir/white spirea habitat type in central Idaho: succession and management. Gen. Tech. Rep. INT-305. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 81 p. 
152. Steele, Robert; Geier-Hayes, Kathleen. 1995. Major Douglas-fir habitat types of central Idaho: a summary of succession and management. Gen. Tech. Rep. INT-GTR-331. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 23 p. 
153. Stickney, Peter F. 1989. Seral origin of species comprising secondary plant succession in Northern Rocky Mountain forests. FEIS workshop: Postfire regeneration. Unpublished draft on file at: U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Fire Sciences Laboratory, Missoula, MT. 10 p. 
154. Stickney, Peter F.; Campbell, Robert B., Jr. 2000. Data base for early postfire succession in Northern Rocky Mountain forests. Gen. Tech. Rep. RMRS-GTR-61-CD, [CD-ROM]. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. On file with: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, Missoula, MT. 
155. Strausbaugh, P. D.; Core, Earl L. 1977. Flora of West Virginia. 2nd ed. Morgantown, WV: Seneca Books, Inc. 1079 p. 
156. Strickler, Gerald S.; Edgerton, Paul J. 1976. Emergent seedlings from coniferous litter and soil in eastern Oregon. Ecology. 57: 801-807. 
157. Stromberg, Julie C.; Patten, Duncan T. 1991. Dynamics of the spruce-fir forests on the Pinaleno Mountains, Graham Co., Arizona. The Southwestern Naturalist. 36(1): 37-48. 
158. Stuart, John D. 1987. Fire history of an old-growth forest of Sequoia sempervirens (Taxodiaceae) forest in Humboldt Redwoods State Park, California. Madrono. 34(2): 128-141. 
159. Stucker, Donald E.; Peek, James M. 1984. Response of bighorn sheep to the Ship Island Burn. Report submitted to the Northern Forest Fire Laboratory: Supplement No. INT-80-108CA. 33 p. On file at: U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Fire Sciences Laboratory, Missoula, MT. 
160. Swain, Albert M. 1978. Environmental changes during the past 2000 years in north-central Wisconsin: analysis of pollen, charcoal, and seeds from varved lake sediments. Quaternary Research. 10: 55-68. 
161. Tande, Gerald F. 1979. Fire history and vegetation pattern of coniferous forests in Jasper National Park, Alberta. Canadian Journal of Botany. 57: 1912-1931. 
162. Thilenius, John F. 1971. Vascular plants of the Black Hills of South Dakota and Wyoming. Res. Pap. RM-71. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 43 p. 
163. Thilenius, John F. 1972. Classification of deer habitat in the ponderosa pine forest of the Black Hills, South Dakota. Res. Pap. RM-91. Fort Collins, CO: U.S. Department of Agriculture, Forest Service. 28 p. 
164. Thompson, Ken; Bakker, Jan P.; Bekker, Renee M. 1997. The soil seed banks of north west Europe: methodology, density and longevity. Cambridge, UK: Cambridge University Press. 276 p. 
165. U.S. Department of Agriculture, Natural Resources Conservation Service. 2008. PLANTS Database, [Online]. Available: http://plants.usda.gov/. 
166. Volland, Leonard A.; Dell, John D. 1981. Fire effects on Pacific Northwest forest and range vegetation. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Region, Range Management and Aviation and Fire Management. 23 p. 
167. Voss, Edward G. 1985. Michigan flora. Part II. Dicots (Saururaceae--Cornaceae). Bull. 59. Bloomfield Hills, MI: Cranbrook Institute of Science; Ann Arbor, MI: University of Michigan Herbarium. 724 p. 
168. Wade, Dale D.; Brock, Brent L.; Brose, Patrick H.; Grace, James B.; Hoch, Greg A.; Patterson, William A., III. 2000. Fire in eastern ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 53-96. 
169. Wallmo, Olof C.; Regelin, Wayne L.; Reichert, Donald W. 1972. Forage use by mule deer relative to logging in Colorado. Journal of Wildlife Management. 36: 1025-1033. 
170. Wang, G. Geoff; Kemball, Kevin J. 2005. Effects of fire severity on early development of understory vegetation. Canadian Journal of Forest Research. 35: 254-262. 
171. Weber, William A. 1987. Colorado flora: western slope. Boulder, CO: Colorado Associated University Press. 530 p. 
172. Weber, William A.; Wittmann, Ronald C. 1996. Colorado flora: eastern slope. 2nd ed. Niwot, CO: University Press of Colorado. 524 p. 
173. Welsh, Stanley L.; Atwood, N. Duane; Goodrich, Sherel; Higgins, Larry C., eds. 1987. A Utah flora. The Great Basin Naturalist Memoir No. 9. Provo, UT: Brigham Young University. 894 p. 
174. Whittaker, R. H. 1960. Vegetation of the Siskiyou Mountains, Oregon and California. Ecological Monographs. 30(3): 279-338. 
175. Wiggins, Ira L. 1980. Flora of Baja California. Stanford, CA: Stanford University Press. 1025 p. 
176. Wofford, B. Eugene. 1989. Guide to the vascular plants of the Blue Ridge. Athens, GA: The University of Georgia Press. 384 p. 
177. Youngblood, Andrew; Metlen, Kerry L.; Coe, Kent. 2006. Changes in stand structure and composition after restoration treatments in low elevation dry forests of northeastern Oregon. Forest Ecology and Management. 234(1-3): 143-163.