Botanical description: This description covers characteristics that may be relevant to fire ecology and is not meant for identification. Keys for identification are available (e.g., [84,88,112,114,255,318]).
Redosier dogwood is a multistemmed, erect to loosely spreading, deciduous shrub that grows 3 to 20 feet (1-6 m) tall and often as wide [31,116,235,312,324]. Shrubs often form clumps or dense thickets by stolons [230,327] and prostrate, rooting stems and lower branches [154,282]. It is these rooting stems and branches that gave redosier dogwood its previously recognized stolonifera species name [88]. While Rickett [245] concluded that these rooting stems and branches are "not differentiated stolons" in redosier dogwood, several authors describe spread via stolons (see Vegetative regeneration). Stolons can extend as far as 10 feet (3 m) from the parent plant (Geisler 1985 personal communication, cited in [93]). Redosier dogwood branches are opposite [235], and twigs are generally less than 2 mm in diameter [286]. Growth form and size of redosier dogwood are highly variable and many local forms exist [36,112]. While most often a multibranched shrub, in areas with a dense grass layer redosier dogwood may be restricted to a single main stem. In Alaska and Alberta, redosier dogwood generally grows 3 to 10 feet (1-3 m) tall, but at more southern latitudes, generally reaches 10 to 20 feet (3-5 m) tall. A near maximum height observed in British Columbia was 30 feet (9 m) [94]. Shrubs growing in full sun are typically dense and compact, with many lateral branches; shrubs growing in shade are typically open and sprawling, with few branches. Redosier dogwood leaves growing in the shade are generally larger and thinner than those growing in full sun [196]. When researchers collected redosier dogwood clones from 21 sites as far north as Alaska and as far south as Colorado, they found no consistent growth form. Extreme upright clones were collected from the upper Midwest, and decumbent forms were collected along the Chalk River in Ontario and Massachusetts. Stems with heavy pubescence were collected from areas with dry, cold, continental climates [281].
Redosier dogwood leaves are simple, entire, and opposite [271], and generally measure 2 to 6 inches (5-15 cm) long and about one-third to two-thirds as wide [84,88,160]. Leaves are mostly oval shaped [112,235,255,312]. Redosier dogwood produces small, perfect flowers that are densely clustered in a terminal, flat-topped to slightly rounded cyme [112,160,255,271,282]. Individual flowers have 4 stamens and 4 petals that are 2 to 4 mm [9,114,235]. Inflorescences generally have 4 to 6 main branches and measure 0.8 to 2.4 inches (2-6 cm) across [88,200]. Redosier dogwood shrubs in West Virginia had small inflorescences with few flowers [289]. Redosier dogwood produces white to blue, berry-like drupes that measure 4 to 10 mm in diameter [200,255,312]. Generally 10 to 30 fruits develop per inflorescence [286].
The redosier dogwood root system was not well described in the available literature (as of 2012). One paper described it as non-taprooted [316].
For descriptions that may be useful in distinguishing redosier dogwood subspecies, see Hickman [112] and Kartesz [137].
Redosier dogwood is a native species that is most common in the northern latitudes of North America [116,200] but ranges widely from Alaska and northern Canada as far south as Virginia, southern California, and Chihuahua, Mexico [36,76,196,230,255]. In its more southern range, redosier dogwood is largely restricted to riparian areas and other moist sites [62,205,332] and is thought to be limited by high temperatures [94]. Cornus sericea subsp. occidentalis is restricted to the western states of Alaska, Washington, Oregon, California, Montana, and Idaho, while Cornus sericea subsp. sericea occurs throughout the redosier dogwood range [307]. For local distribution information, consult the county-level maps available at the PLANTS Database.
States and provinces (as of 2011 [307]):
United States: Cornus sericea L. subsp. sericea: AK, AZ, CA, CO, CT, DE, IA, ID, IL, IN, KS, KY, MA, MD, ME, MI, MN, MT, ND, NE, NH, NJ, NM, NV, NY, OH, OR, PA, RI, SD, UT, VA, VT, WA, WI, WV, WY
Canada: AB, BC, LB, MB, NB, NF, NS, NT, NU, ON, PE, QC, SK, YT
Mexico [76,230]
United States: Cornus sericea L. subsp. occidentalis: AK, CA, ID, MT, NV, OR, WA
The average fire-return intervals reported for upland and riparian sites that would likely support redosier dogwood populations ranged from 10 years in forests in the Payette National Forest of Idaho [11] to 70 years in primarily white spruce forests of northeastern Alberta [158], but given redosier dogwood's widespread distribution and varied habitats, this fire frequency range would likely be much larger with additional fire history studies. For a more extended discussion of FIRE REGIMES in riparian and upland sites, which likely included habitats where redosier dogwood might also occur, see the FEIS review of thimbleberry (Rubus parviflorus).
Reviews report that high productivity and fuel build-up in riparian zones may fuel high-severity fires. Deciduous riparian communities along perennial waterways in eastern Idaho and western Wyoming are considered highly productive with the potential to accumulate large amounts of live and dead woody fuels and support "high-intensity" fires in times of drought when winds are strong (review by [33]). In the conifer/redosier dogwood community type in moist to wet subalpine riparian sites in Utah, fires are considered infrequent. When fires do occur, they may be severe because of high fuel loads, although small, low-severity, smoldering fires are considered most common [34].
Field investigations suggest that topography within the riparian zone may affect fire severity. On the Plumas National Forest in the northern Sierra Nevada, fire was more severe along Fourth Water Creek–where riparian zones were wide and flat–than along Third Water Creek, where riparian zones were narrow and steep. Fire pattern and severity were evaluated 1 year after the Lookout wildfire burned in late August and early September. Fires burned to the water's edge less often on Third Water than Fourth Water creek, suggesting that width of the riparian zone was negatively correlated with the extent of riparian area burned. About half of transects along Fourth Water Creek burned with moderate to high severity and had some crowning behavior. Third Water Creek burned primarily in low- to moderate-severity surface fires, but these fires did result in some mortality of understory vegetation [144].
Riparian and upland communities compared: Fire frequency and fire behavior were often similar in riparian and upland sites. In Idaho's Payette National Forest, moderate to large, mixed-severity fires burned upland and riparian forests an average of every 10 years from 1471 to 1948, but since 1948, the fire-free interval for the area has increased by a factor of 8 (Barrett 2000 cited in [11]).
Sometimes stream size, extent of riparian vegetation, or vegetation type were better predictors of fire behavior and fire frequency than slope position or distance from the river. In Oregon, comparisons of riparian and upland sites burned by the Biscuit Fire and by the B and B complex fire revealed that fire severity differences between upland and riparian sites depended on which measure of fire severity was used. At both burned sites, percent crown scorch and basal area mortality (indicators of overstory fire severity) were not significantly different for riparian and upland sites, but percentage of exposed mineral soil and char heights (indicators of understory fire severity) were significantly lower (P<0.01) for riparian than upland sites. Regression analyses suggested that upland fire severity was the strongest predictor of basal area mortality in riparian areas. Within the Biscuit Fire perimeter, overstory fire severity was greater in riparian areas with dense small trees, and understory fire severity was greater in areas with higher basal area of hardwoods, but this same pattern was not observed within the B and B complex fire perimeter. Within the B and B complex, overstory fire severity was significantly greater (P<0.05) in relatively dry riparian areas dominated by ponderosa pine than in relatively wet riparian areas dominated by a mixed of conifers. In both areas, basal area mortality was lower along large than small streams, and fires were generally less severe along low-gradient than high-gradient streams [96].
See the Fire Regime Table for additional information on FIRE REGIMES in vegetation communities where redosier dogwood 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".
Fire adaptations: A review of the available literature (as of 2012) suggests redosier dogwood stems on burned sites are most likely the result of root crown, stem, or stolon sprouting. Reviews, however, report more varied postfire establishment methods, such as establishment from heat-activated, soil-stored seed (reviews [33,279]), and suggest that redosier dogwood regeneration is favored by low-severity fires that remove little of the organic layer because of long-term seed bank inputs and a natural filtering of redosier dogwood seeds through the soil surface into the upper mineral soil (review by [258]). Investigations into redosier dogwood's potential survival and establishment on burned sites were uncommon in the literature (as of 2012). While redosier dogwood survival on burned sites was common [10,194,244], it was not guaranteed [169,170], and while one study suggests redosier dogwood seeds are somewhat heat tolerant, heating with boiling water did not improve germination [227].
Plant response to fire: Several studies reported that redosier dogwood survived on burned sites by sprouting, and in one case, sprouts occurred within 7 days of burning. Researchers reported that redosier dogwood was rarely if ever killed by spring and summer prescribed fires in old fields at New York's Iroquois National Wildlife Refuge. These prescribed fires reached a maximum of 134 kW/m energy release and a maximum surface temperature of 504 °F (262 °C) [194]. Redosier dogwood was only top-killed after cut shrubs were burned by torching in a sedge meadow in Marquette County, Wisconsin. Sprouting was vigorous and usually occurred within 7 days of treatments [244]. Redosier dogwood emerged from soil samples collected within a week of an April fire that burned in even-aged mixed forest near Fishing Lake, Saskatchewan. Redosier dogwood stems sprouted from root or stem material in the soil samples, which were put in a lighted greenhouse. There were 2 to 5 redosier dogwood germinants/plot in soil samples from plots burned by light to moderate surface fire. There were no germinants from soil collected from severely burned plots or unburned plots [10].
Redosier dogwood seeds appear to be heat tolerant [227], and seedlings were reported within a year of burning in a riparian site in the northern Sierra Nevada [144]. Germination of redosier dogwood seed collected from Lincoln County, Montana, was evaluated after a variety of treatments. Only 20% of seeds germinated after they were treated with boiling water, allowed to cool, and then stratified, but almost 70% of treated, ungerminated seeds remained viable [227]. On the Plumas National Forest in the northern Sierra Nevada, redosier dogwood recovery after fire was monitored along Third Water and Fourth Water creeks. The fire burned more severely along Fourth Water Creek than Third Water Creek. Survival of redosier dogwood was similar along both creeks, with most shrubs sprouting from either root crowns or stems and rarely sprouting from both. Density of redosier dogwood seedlings was greater at the more severely burned Forth Water Creek area (26 seedlings/480 m²) than the Third Water Creek area (1 seedling/567 m²) [144]. For more information about the pattern of burning in this and other riparian areas, see FIRE REGIMES.
One study suggests that redosier dogwood may not always survive fire. In a Douglas-fir forest, north of Ketchum, Idaho, redosier dogwood was present before but not 1 to 7 years after a prescribed fire. The fire burned on 1 August when air temperatures reached a high of about 80 °F (27 °C), relative humidity reached a low of 10% or less, and wind speeds averaged about 5 miles (8 km)/hour. All litter, herbaceous material, logs less than 3 inches (8 cm) in diameter, and all live stems less than 2 inches (5 cm) in diameter were completely consumed by the fire [169,170]. For more information on this prescribed fire and community response during the first 2 postfire years, see the research paper by Lyon (1966).
In most fire studies, redosier dogwood abundance was reduced only in very early postfire sampling or was relatively unchanged by fire. By the 2nd postfire growing season following a prescribed fire in mixed quaking aspen and Douglas-fir stands in Montana's Gallatin National Forest, density of redosier dogwood was near or exceeded prefire levels. Fire ignition was attempted on 30 April, but because of poor fire spread another fire was set on 16 May when relative humidity was 20% and air temperature was 70 to 80 °F (21-27 °C). The May fire consumed 90% to 100% of fine fuels and penetrated 2 to 4 inches (5-10 cm) deep [87].
Density of redosier dogwood stems (number/acre) before and after a prescribed fire in mixed forests on the Gallatin National Forest of Montana [87] Transect Prefire 1st postfire growing season 2nd postfire growing season 1 1,486 1,069 1,328 2 1,036 259 1,133 3 1,236 664 1,231In quaking aspen woodlands in southern Ontario, frequency of redosier dogwood was not different between burned and unburned plots, 4 months or 15 months after a low-severity surface fire. However, cover of redosier dogwood was significantly lower on burned than unburned plots (P<0.05). On 4-month-old burned plots, redosier dogwood cover averaged about 35%; on 15-month-old burned plots, cover averaged about 45%. Redosier dogwood cover on unburned plots was about 60%. Most aboveground redosier dogwood stems were killed by the fire, but underground portions of the shrubs were undamaged, and root crown sprouting was prolific [276]. For more information about this fire and its pattern of burning, see Fuels. In old fields at New York's Iroquois National Wildlife Refuge, the density of redosier dogwood stems was not reduced from prefire levels when mowed shrubs were burned in a summer fire [194].
Fire studies in Wisconsin report little change in redosier dogwood abundance after fire. In a sedge meadow at Summerton Bog Nature Preserve in Wisconsin, redosier dogwood decreased only slightly from pretreatment levels after shrubs were mowed and then torched [244]. Redosier dogwood cover was not changed by a winter prescribed fire in sedge meadow and shrub carr vegetation at Lodi Marsh in southern Wisconsin. In the sedge meadow, cover of redosier dogwood was 5% on both burned and unburned plots, and in the shrub carr, redosier dogwood cover was 8% on both burned and unburned plots. Cover on burned plots was evaluated 1 to 2 years after the 13 December fire, which burned when the air temperature was 45 °F (7 °C) and relative humidity was 55%. Flame lengths reached 3 feet (1 m), and nearly all surface litter was consumed [192].
After spring prescribed fires in Minnesota and Wisconsin, both increases and decreases in redosier dogwood stem density occurred. Changes between prefire and postfire stem densities were not consistently related to the composition of stands, fire season, fire spread rates, or fire intensity. Prescribed fires occurred in the spring or fall, when most vegetation was probably dormant. Air temperatures ranged from 55 to 78 °F (13-26 °C) and relative humidities were 22% to 49% at the time of burning. Fires were conducted 4 to 9 days after the last rain, and fuel moisture contents ranged from 8.3% to 14.8%. Density of redosier dogwood stems was evaluated at the end of the 1st postfire growing season [6].
Density of redosier dogwood stems before and after prescribed fires in quaking aspen and mixed hardwood stands in Minnesota and Wisconsin [6] Site characteristics Fire characteristics Redosier dogwood stem density (number/ha) Season Energy (kJ/m²) Rate of spread (m/min) Frontal fire intensity (kW/m) Prefire Postfire Site 1: mixed hardwood Spring 4,570 1.8 139 1,656 988 Site 2: pure quaking aspen Spring 4,560 8.8 672 8,648 10,020 Site 3: mixed hardwood Spring 4,560 1.8 139 1,606 988 Site 4: mixed hardwood Spring 4,553 1.5 115 791 2,076 Site 5: mixed hardwood Fall 4,531 2.1 161 1,680 1,384 Postfire tree mortality (5.1-10.2 cm diameter size class) was greatest at Site 2, next greatest at Site 3, and least at Site 6.Early postfire succession: Redosier dogwood has been reported on burned sites 100 days to 30 years following fire. Redosier dogwood occurred on burned plots 100 days after a severe fire in a northern white-cedar-balsam fir stand near Ottawa, Ontario. The wildfire occurred on 23 June 1999, spread at a rate of 16 feet (5 m)/minute, and produced flame heights of more than 100 feet (30 m). The stand had not burned since 1870 [44]. In mixed-conifer forests in northern Idaho's Bitterroot Mountains, redosier dogwood often occurred within 2 to 3 years of fire on moist sites [159]. In treeless muskegs of north-central Wisconsin, redosier dogwood was classified as an invader on sites burned by prescribed fire. Although precise time since fire associated with redosier dogwood establishment was not provided, it was likely within 10 years of burning [314]. In southeastern Wisconsin, redosier dogwood was the most common shrub in quaking aspen woodlands about 30 years after a severe fire in a marl and peat marsh. The fire started in August and continued to burn through the winter. In some areas with dry peat, the fire burned a foot (0.3 m) deep [315].
Fires and logging: Although abundance may be reduced, redosier dogwood typically survives in burned clearcut stands. On a clearcut site in the Mackenzie Forest District of British Columbia, average redosier dogwood cover was greater before than after prescribed burning. In the western white spruce (Picea glauca × P. engelmannii)-devilsclub forest type, redosier dogwood cover averaged 1.8% after clearcutting. Cover was less than 1% in the 1st growing season after a low- to moderate-severity, fall prescribed fire. By the 10th postfire year, redosier dogwood cover was still less than 1%; however, frequency of redosier dogwood was greater in the 10th postfire year than it was in clearcut and unburned stands [98]. When disturbed and undisturbed western redcedar-western hemlock stands in northern Idaho were compared, redosier dogwood did not occur in undisturbed, closed-canopy stands. Frequency of redosier dogwood ranged from 1% in logged but unburned stands to 12% in logged and pile burned stands. The age of disturbed stands ranged from 11 to 40 years [202]. In boreal mixedwood stands in southeastern Manitoba, the cover and frequency of redosier dogwood in logged stands averaged 5.3% and 10%, respectively. In burned stands cover and frequency averaged 1.8% and 8%, and in stands impacted by severe bud worm outbreak, cover and frequency averaged 1.3% and 5%. Time since disturbance in the stands ranged from 10 to 16 years [140]. In mixed-hardwood stands in Minnesota's Chippewa National Forest, dogwoods (redosier dogwood and alternate-leaf dogwood) made up a much greater proportion of plots that were burned 2 years after clearcutting than plots that were not burned after clearcutting. Stands were evaluated for the first 8 years following disturbance. The prescribed fire burned in May when the previous 6 days had been free of rain, relative humidity was 29%, air temperature was 69 °F (20.6 °C), and wind speed was 16 feet (5 m)/second. The fire consumed nearly all fuels less than 3 inches (7.6 cm) in diameter. The researcher reported that dogwoods were "encouraged" by fire [225].
Multiple fires: In the Great Lakes region, redosier dogwood occurred on repeatedly burned sites. In northwestern Minnesota's Beltram Island State Forest, prescribed fires were set in May of 1968, 1971, 1973, and 1975. Each fire burned 59% to 90% of the study area, which was, at the time of the first fire, dominated by mature quaking aspen. The researchers reported that most of the quaking aspen stands were converted to shrublands dominated by plums (Prunus spp.) and redosier dogwood after burning [24]. In oak savannas in east-central Minnesota, 2 to 19 prescribed fires were conducted over a 20-year period, primarily in the spring. Regression analyses indicated that redosier dogwood decreased with increasing fire frequency (r = -0.233), but the relationship was not significant (P=0.476) [293]. At Summerton Bog in central Wisconsin, 2 consecutive spring fires failed to reduce shrub cover, and after the fires, redosier dogwood "appeared to" increase [321].
Cold stratification generally improves germination of redosier dogwood seed. Other factors potentially affecting germination, such as light and depth of seed burial, were not discussed in the available literature (2012).
In the laboratory, high germination percentages were reported for cold stratified redosier dogwood seed. Seeds stored for 120 to 160 days at 37 to 41 °F (3-5 °C) then exposed to temperatures of 68 to 86 °F (20-30 °C), had high germination rates (80%-90% within 28 days) [22]. In other laboratory studies, seed germination averaged 57% after cold stratification at 36 to 41 °F (2-5 °C) for 60 to 90 days [38]. A regimen of soaking for 1 to 2 days, followed by cold stratification at 36 °F (2 °C) for 4 to 6 months, followed by exposure to a daytime temperature of 75 °F (24 °C), a nighttime temperature of 68 °F (20 °C), and 20-hour day lengths resulted in higher germination rates than other regimens tested [120]. Redosier dogwood seed that was soaked in sulfuric acid and then cold stratified had germination rates about twice that of untreated seed or seed that was only stratified. These researchers suggested that redosier dogwood may have double dormancy and that stratification alone does not result in complete germination [150].
In studies that compared the germination of redosier dogwood seeds that were kept indoors and those kept outdoors, those that experienced cold outdoor conditions generally germinated better than those kept in the greenhouse. Redosier dogwood seeds collected in northern Michigan germinated better (25%) and faster (in 21-277 days) after 71 to 112 days in an outdoor cold frame than unstratified seeds in a greenhouse (14% germination after 252-510 days) [213]. Redosier dogwood seeds collected from Lincoln County, northwestern Montana, were exposed to a variety of treatments: artificial scarification with sand paper; winter chilling by keeping seeds outdoors in January, February, and March; artificial stratification with refrigeration at 35 °F (2 °C), and artificial heating by pouring boiling water over seeds and then allowing them to cool to room temperature. Germination was best (87%) for seeds treated with artificial stratification. Germination was 69% for winter-chilled seeds, 30% for scarified and winter-chilled seeds, and 20% for artificially heated seeds. The percentage of nongerminating seeds that remained viable after the treatments was 70% for artificially heated seeds, 33% for winter-chilled seeds, and 12% for stratified and scarified seeds [227].
Although most studies reported that redosier dogwood seed germination improved with cold stratification, Adams [2] obtained 76% germination of fresh seeds from fruits collected in September. Fruit pulp was removed and seeds were planted in a greenhouse. When the same seed lot was put outdoors, germination was 73%. Germination was 35% for seeds that were dried and stored at room temperature for a year before spring planting [2].
When researchers compared the germination of redosier dogwood seeds collected for 3 years from 55 natural populations in central and northern Alberta, they found that germinability was strongly influenced by population but that populations with similar germinability could be scattered over a wide area. All seeds were stratified before germination testing. Many populations had germination rates of 80% after only 4 weeks. Seeds produced in the driest year had the lowest germination percentages [1].
Several studies indicate that viability of redosier dogwood seeds is retained after digestion by birds and mammals [68,150,254]. For details see Seed dispersal.
Redosier dogwood provides important food and cover for many mammals and birds [167]. Moose, elk, deer, bighorn sheep, mountain goats, beavers, and rabbits commonly browse redosier dogwood stems [23,26,27,235,313]. Bears, small mammals, and birds consume redosier dogwood fruits and seeds [138,313]. Livestock also utilize redosier dogwood [100,137]. In Montana, redosier dogwood is referred to as an "ice cream" plant for wildlife and livestock [100]. New shoot growth is an important food source, especially for moose and deer [247]. Twigs have also been referred to as preferred, extremely important, and highly valuable winter browse [197,235,312]. Fruits are consumed in the summer and fall [164,247]. A gardening guide reports that redosier dogwood fruits are eaten by 47 different bird species [164]. Redosier dogwood shrubs are also important nesting habitat and summer cover [164,247].
Use of red-osier dogwood for food, cover, and/or nesting by a variety of wildlife and livestock species is discussed in the reviewed literature (as of 2012). The discussion that follows does not likely capture the true variety and extent of redosier dogwood use by wildlife and livestock.
Ungulates: Nearly throughout its range, redosier dogwood is browsed by a variety of ungulates. Redosier dogwood was considered highly important browse for mountain goats, elk, and moose in British Columbia (review by [27]). In the Glacier Park area of northwestern Montana, redosier dogwood received high levels of use by moose and elk in the winter and by white-tailed deer in winter and summer [130,274]. On a 2-year-old burned site in the boreal forest region northwest of Ely, Minnesota, moose browsed redosier dogwood in October and white-tailed deer browsed it in May and April [128].
Moose: Redosier dogwood has been reported as an important food for moose throughout much of the temperate North American region. Winter use was most commonly reported but fall, spring, and summer use also occurred [74,222,297].
In the western United States, moose utilization of redosier dogwood can be extensive. In an area of southwestern Montana receiving concentrated moose use in the winter, "virtually all" of the current year's growth of redosier dogwood was removed in each of 4 years of observations [223]. On the north slope of the Gallatin Range, redosier dogwood was heavily browsed by moose in winter and remained important browse into the spring [287]. In logged areas of the Yaak River drainage, moose frequently browsed redosier dogwood [177]. In Fremont County, Idaho, moose fed on redosier dogwood. Moose diets did not contain a great abundance of redosier dogwood but only because of its sparse distribution in the study area [250]. In Jackson Hole, Wyoming, use of redosier dogwood by moose was so extensive that the researcher suggested it may be eliminated from the winter range. Redosier dogwood stems were "virtually cleaned out long before the winter got underway" [105]. In another study of the Jackson Hole area, moose use of redosier dogwood was sometimes as much as 15% of the total feeding observations. On winter range, 40% to 58% of redosier dogwood shrubs were severely browsed between 1964 and 1966 [117]. In the Snowy Range of Wyoming, however, redosier dogwood was seldom recovered from moose feces although it occurred within the quaking aspen stands interspersed in the study area's predominantly coniferous forests [14].
Redosier dogwood was important moose browse in Canada and the Great Lakes region. Contents of moose rumen samples collected from southeastern Manitoba in early winter indicated heavy use of redosier dogwood, which occurred in 82.6% of all rumens. Among the 25 taxa identified in the rumen samples, redosier dogwood was considered most important, and field observations revealed that redosier dogwood shrubs were heavily browsed [335]. In northern Ontario, an average of 53% of redosier dogwood stems was browsed by moose in studies between 1955 and 1970 [53]. In clearcut boreal forest sites in the northwestern part of the province, redosier dogwood was 1 of the 4 most heavily browsed species and 1 of just 2 preferred species in the winter [300]. In the northeastern part of Ontario, redosier dogwood was important browse for cow-calf moose on sites logged 1 to 40 years earlier. Of the available redosier dogwood stems, more than half (56.6%) were removed in early winter and a little less than half (46.5%) were removed in late winter [295]. On Isle Royale, Michigan, redosier dogwood has been described as a "favorite" summer and a "relished" winter moose food. Redosier dogwood plants that are not heavily browsed were rare, and stunted growth forms were common because of heavy browsing [208]. In other studies of moose on Isle Royale, redosier dogwood made up a high of 25.6% and a low of 5.3% of moose diets [149]; use typically exceeded availability [148].
Elk: Use of redosier dogwood by elk was reported in Idaho, Montana, Manitoba, and Ontario [80,108,239,256]. On the Selway Game Preserve in Idaho County, redosier dogwood was considered highly palatable to elk, but because of its rarity in the study area, relative importance in elk diets was low [333]. Along the Flathead River in western Montana, elk utilized redosier dogwood heavily in the winter. It was one of the shrub species that was still accessible in deep snow on the 418,000-acre (169,000 ha) winter range, which supported about 2,600 elk [80]. Elk browsed redosier dogwood significantly more than other available browse (P<0.05) when all transects were combined for the study area in Riding Mountain National Park, Manitoba [256]. In mixed-forest habitats in east-central Ontario, a reintroduced elk population selected dogwood (redosier dogwood and roundleaf dogwood) more than expected based on availability [108].
Deer: Mule deer and white-tailed deer use of redosier dogwood can be extensive in the summer and winter. A review indicates moderate use of redosier dogwood by mule deer in the fall and winter and heavy use in the summer [152]. In Banff and Jasper National Parks in Alberta, redosier dogwood was preferred winter deer browse [74]. In captive feeding trials, redosier dogwood was important browse for mule deer browse through the summer and was consumed more in August and September than in June and July. Overall, redosier dogwood was the 2nd most preferred browse species in about 30 total browse species. Browse for the feeding trials was collected near Logan, Utah [275].
Redosier dogwood is considered important white-tailed deer browse from Montana to Michigan and Quebec. In the Missouri River breaks area of Montana, white-tailed deer ate redosier dogwood most often in summer, little in fall, and not at all in spring or winter [8]. In the Sun River Area of west-central Montana, redosier dogwood received 18% of the instances of browse use by white-tailed deer along rivers and in seep habitats [268]. However, in coniferous forests in the Upper Swan Valley, redosier dogwood made up a small portion of winter white-tailed deer diets (high of 0.3% in January) [206]. When availability and use of browse species were compared in the Black Hills of South Dakota, redosier dogwood ranked as highly palatable to white-tailed deer from January to March and July to September [113]. At 3 sites in northeastern Minnesota, use of redosier dogwood exceeded its availability in early winter and approximated its availability in late winter [61]. In a 2-year study in Louis and Lake counties in southeastern Minnesota, redosier dogwood was utilized "intensively" in heavily populated winter range and was selected more than expected based on availability in the early summer [325]. At the Mud Lake National Wildlife Refuge in Minnesota, redosier dogwood was considered the most highly preferred winter browse species by white-tailed deer, and its use increased as winter progressed [127]. In the Rigaud white-tailed deer yard in southwestern Quebec, winter use of redosier dogwood ranged from 61% to 78% over 3 years. At the end of March, redosier dogwood was avoided [40]. In Wilderness State Park, Michigan, white-tailed deer browsed redosier dogwood heavily in the winter [118].
Bighorn sheep: In Canadian National Parks, redosier dogwood was utilized heavily in midsummer by bighorn sheep [285].
Other mammals: Redosier dogwood fruits and stems are an important food source for bears and several small mammals.
Bears: Black bears from California to Newfoundland and grizzly bears eat redosier dogwood fruits. A review of grizzly bear food items from the northern Rocky Mountains and southern British Columbia ranked redosier dogwood fruits as moderately used food items [171]. In the Kimsquit River Valley, coastal British Columbia, scat analyses and observations from feeding sites indicated that redosier dogwood berries were eaten by grizzly bears but were not 1 of the 6 food items making up the bulk of diets [97]. In northwestern Montana, thinleaf huckleberry is a preferred late summer-early fall food for grizzly bears. On the North Fork of the Flathead River, redosier dogwood was commonly consumed as an alternative food when huckleberry crops failed [215]. From grizzly and black bear scat collected in Glacier National Park, the frequency and volume of redosier dogwood was 1.12% and 0.54%, respectively [141]. In another study in northwestern Montana, grizzly bear use of redosier dogwood was reported as 5.7% (Husby and others 1977 cited in [261]). Redosier dogwood fruits were recovered from black bear scat collected in Sequoia National Park, California. From a total of 555 scat collections, the frequency and volume of redosier dogwood averaged 2% and 0.7%, respectively. Maximum frequency and volume came from scat collected between 20 July to 16 August was 11% and 3.2%, respectively. Redosier dogwood did not occur in scat collected earlier than 20 July [85]. In north-central Minnesota, redosier dogwood was "regularly" found in black bear scat [216]. Frequency of redosier dogwood in black bear scat collected in late summer from Gaspésie Park, eastern Quebec, was 33% [30]. In Gros Morne National Park, Newfoundland, redosier dogwood was not recovered from bear stomachs or scat collected in spring or early summer, but ranged from 0% to 15.6% of the contents in the late summer-fall season after 3 years of collections [56].
Small mammals: A variety of small mammals feed on redosier dogwood stems and fruits. Redosier dogwood was listed among plants most commonly taken by beavers in Nevada (Scheffer 1941 cited in [91]), and in North Dakota it was considered a major winter food source for beavers (Hammond 1943 cited in [7]). In north-central Minnesota, snowshoe hares browsed more than 20% of available redosier dogwood stems [229], and near Syracuse, New York, cottontail rabbits fed extensively on small branches and shoots of redosier dogwood in the winter [299]. Redosier dogwood was among the materials found in bushy-tailed woodrat food caches in California (review by [278]). Redosier dogwood fruits and seeds were found in 1 of 71 least chipmunk stomachs and 1 of 30 least chipmunk cheek pouches from captures made in August and September in northern Minnesota. In both the stomach and cheek pouches, redosier dogwood made up 100% of the contents [3]. In feeding experiments, caged meadow jumping mice fed heavily on redosier dogwood fruits [238].
Birds: Many bird species feed on and disperse redosier dogwood fruits and seeds. In New England, alone, redosier dogwood occurred in the diets of 95 bird species (review by [196]). Individual studies highlight that redosier dogwood fruits were consumed by American crows [110], American robins (personal observation in [330]), catbirds [214], eastern bluebirds, pheasants [150], and ruffed grouse [125]. Eastern bluebirds using nest boxes in Macomb County, Michigan, fed redosier dogwood fruits to nestlings but only in the last week of the nestling period (late June). When fed to nestlings, redosier dogwood fruits made up a high of 37% of nestling diets [231]. On the University of Idaho Experimental Forest in Latah County, utilization of redosier dogwood seeds exceeded availability as determined by scat collected in the late summer and fall [125].
Redosier dogwood is also utilized by birds for nesting and cover. The frequency of mountain quail sightings was 7.5% in red alder/redosier dogwood habitat types in the Hell's Canyon National Recreation Area, which was more than expected if sightings were randomly distributed among available habitat types. Red alder/redosier dogwood habitats were used more in the spring and summer than in the fall and winter [236]. In southeastern Michigan, 2.5% of all identified catbird nests were in redosier dogwood shrubs [214]. At High Island, Michigan, redosier dogwood was common at woodcock roosting sites [326]. Redosier dogwood was considered important cover for ruffed grouse based on a review of revegetation and reclamation guides by Hardy ([101]).
Amphibians: When reproduction of northern leopard frogs was evaluated in floodplain habitats along the Richelieu River in Quebec, researchers found that the reed canarygrass/redosier dogwood habitat type was utilized most for egg deposition. In the reed canarygrass/redosier dogwood habitat type there were 140 egg masses, and in the next most heavily utilized habitat type, purple loosestrife/river bulrush (Lythrum salicaria/Schoenoplectus fluviatilis), there were 28 egg masses [82].
Livestock: While some indicate that all classes of livestock avoid redosier dogwood unless more preferred foods are unavailable [218], others suggest that redosier dogwood is an "ice cream" plant for livestock and wildlife [100]. During a 2-year study on a grazing allotment in the southern Blue Mountains of Oregon, cattle concentrated in the riparian zone early in the grazing season and utilized redosier dogwood considerably in one year but not the next [251].
Palatability and nutritional value: General descriptions of redosier dogwood's palatability are highly variable. Merigliano [190] suggests that redosier dogwood is palatable at all growth stages. While Sampson and Jespersen [266] indicate that young redosier dogwood sprouts are consumed to some degree but that stems are only browsed close to the ground when more palatable foods are unavailable. General palatability of redosier dogwood was rated as fair to poor for goats and deer, poor for sheep, and poor to useless for cattle in California [266]. The value of redosier dogwood was considered low for cattle, horses, and elk in Nevada and eastern California [174], but in Colorado and Wyoming, redosier dogwood palatability was rated as fair in the fall [57]. The above section on the Importance of redosier dogwood to Wildlife and Livestock should be considered in conjunction with general palatability ratings to appreciate the potential importance of redosier dogwood as wildlife and livestock browse.
Several studies provided information on the nutritional content of redosier dogwood stems and fruits from various locations and at different seasons. In the Quenel region of British Columbia, redosier dogwood ranked as low-quality ungulate browse from November through May. Although it was highly palatable, protein content averaged 4.8%. Researchers reported no change in protein content in forest stands of different ages [52]. At the western boundary of Glacier National Park, Montana, crude protein averaged 5.8% and digestible dry matter averaged 41.8% in redosier dogwood stems collected in winter [130]. In Minnesota, researchers determined the average nutrient content of redosier dogwood stems from September through June. Based on dry weight, protein content was 6.7% and crude fat was 4.2%. The lower portions of redosier dogwood branches were less nutritious than upper portions [71]. A database has been developed for easy look-up of the nutritional content of redosier dogwood and many other browse species in the northeastern United States. For details, see [219].
Redosier dogwood fruits are especially high in fat content. In Alaska, the lipid content of redosier dogwood fruits was more than 25% of the dry pulp weight (Willson unpublished data cited in [329]). Based on comparisons with other collected fruits, redosier dogwood fruits collected in late summer from the Rainbow Creek Natural Area of southeastern Washington had high lipid levels [232] and moderate protein, fiber, and ash levels [233]. In a study of fruits collected from northern Ontario, redosier dogwood fat content was 2nd highest among 17 browse species evaluated, and protein content was 6th highest [308]. The nutritional content of fresh redosier dogwood fruits collected from central Pennsylvania averaged: 2.2% crude protein, 8.3% crude fiber, and 1.8% available protein. Nutritional values were much greater for dry than fresh fruits [319].
Cover value: Although cover value of redosier dogwood was not often described in detail in the reviewed literature (as of 2012), its multibranched structure and sometimes large size (see Botanical description) suggests it probably provides important cover for many wildlife species. A review reports that redosier dogwood provides dense summer and partial winter cover for birds and small mammals [196]. In Montana, redosier dogwood is common in the understory of many coniferous and deciduous riparian vegetation types, which provide important (rated as good to excellent, usually) thermal and hiding cover for wildlife and livestock [100].
American Indians ate redosier dogwood fruits and utilized redosier dogwood stems and bark in tonics and emetics to treat ailments, in smoke for an intoxicating effect, and in the construction of structures and tools. The Flathead and Kootenai ate a "sweet and sour" mixture of serviceberries (Amelanchier spp.), redosier dogwood fruits, and sugar [106]. A review reports that redosier dogwood was used in gynecological medicines by aboriginal people of northwestern North America [304]. The Quileute and Salish used redosier dogwood bark in tonic tea to treat fevers and coughs [200,235]. The Salish from the Saanich Peninsula of Vancouver Island soaked redosier dogwood bark in warm water and drank enough of the extract to induce vomiting. This treatment served to cleanse the stomach and improve breathing. The redosier dogwood extract is still drunk by canoe pullers before races [303]. The inner bark of redosier dogwood stems was dried and smoked by American Indians for a narcotic effect [173]. Blackfeet in the northwestern Great Plains [131] and other tribes in Montana were said to smoke redosier dogwood [106]. Redosier dogwood stems were utilized in various types of tools and construction. The Dena'ina of south-central Alaska used redosier dogwood stems in basketry [135]. The Chumash of California used long redosier dogwood stems as fishing poles and in the construction of canoes and baby cradles [296]. The Flathead and Kootenai used redosier dogwood to make arrows, drumsticks, and tepee stakes [106].
Families living in Quebec in the first part of the 20th century believed that daily ingestions of redosier dogwood would prevent a miscarriage [265]. Neither the portion of the plant used or preparation of the plant material was described.
Redosier dogwood flowers in spring. Flowering may occur slightly earlier in the southern part of its range (May) [43,137,138,175,207,313] than in the northern part of its range (June) [195,255,282,312]. Often redosier dogwood flowers twice in a growing season. In the Adirondack Uplands of New York, redosier dogwood flowered in early June, and after fruits matured in August, there was often a second blooming season. In this region, redosier dogwood was the first and last dogwood species blooming [45]. In the northeastern United States, redosier dogwood flowers first in May or June and flowers again in late summer [247]. This flowering pattern has also been reported in Colorado [139] and the northern Great Plains [286]. In 9 years of observations made in northeastern Illinois and southeastern Wisconsin, the earliest redosier dogwood flowers appeared on 4 May and the latest on 25 September [292]. Mature redosier dogwood fruits are generally available from July to November [173,217,266,286,312,313].
In a common garden experiment, researchers found that fall phenology events such as changes in stem and leaf color and leaf abscission were largely controlled by photoperiod, and spring phenology events such as bud break and flowering were largely controlled by temperature. Growth, however, was largely controlled genetically. These redosier dogwood clones collected from 21 sites ranging from latitudes of 40 to 65 degrees were grown in a common garden in St. Paul, Minnesota [281].
In a 60- to 80-year-old boreal mixedwood forest near Lac La Biche, Alberta, starch content of stolons increased from spring to late summer and fall. Sugar content was greatest in September and much lower in June, July, and August [157]. In Massachusetts, the concentration of starch in current year's stem growth was highest in October, decreased through the fall, and was barely detectable in January. Starch content increased in the spring and summer with peaks in April and August, but decreased to about half or less by October. Total sugar content was inversely related to starch content [13]. Redosier dogwood stems collected in northern Alberta had starch in October and May, but there was little to no starch in stems in December and February. Oils and fats were present in stems in all months of anaylsis including October, December, February, and May [306].
Redosier dogwood reproduces sexually from seed. It regenerates from aboveground stems, stolons, and/or root crowns following stem damage or top-kill [10,144,221,244,276], and rooting of prostrate stems is important to the development of redosier dogwood thickets and large clones [103,107,312].
No studies (as of 2012) described the potential longevity of soil-stored redosier dogwood seed. The potential for long-distance animal dispersal of redosier dogwood seed makes determination of the source and age of redosier dogwood seed from collected soil samples difficult. Seed banking experiments that involve placing and recovering a known quantity of seeds over time would improve our understanding of redosier dogwood seed banking dynamics. Reviews report that redosier dogwood establishes from heat-activated, soil-stored seed [33,279], and that regeneration is favored by low-severity fires that remove little of the organic layer because of long-term seed bank inputs and a natural filtering of redosier dogwood seeds through the soil surface into the upper mineral soil [258]. Redosier dogwood seedlings established within 1 year of fire in riparian areas burned by low-severity and high-severity fires in the northern Sierra Nevada [144].
In laboratory studies, dried redosier dogwood seeds stored in sealed containers at 37 to 41 °F (3-5 °C) remained viable for 2 to 4 years [22].
Few viable redosier dogwood seeds have been found in forest soil samples, regardless of its presence or abundance in aboveground vegetation. In British Columbia, a single redosier dogwood seedling emerged from soil collected in an area with no redosier dogwood shrubs in the aboveground vegetation [182] but did not emerge from soil collected from an area where redosier dogwood shrubs did occur in the aboveground vegetation [284]. When soil was collected from undisturbed, mid-seral forests and adjacent disturbed power line rights of way in southwestern British Columbia, 1 redosier dogwood seedling emerged from soil collected in the mid-seral forest where redosier dogwood shrubs were absent from the aboveground vegetation [182]. Redosier dogwood did not emerge from any soil samples collected from uncut forest, 1-year-old burns, and 1-year-old clearcuts in south-central British Columbia, although redosier dogwood occurred in the study area (frequency up to 11%) [284]. Only 1 viable redosier dogwood seed was found in soils samples collected from 62- to 180-year-old grand fir/thinleaf huckleberry (Vaccinium membranaceum) stands in central Idaho. Soil samples were collected in the summer and stored at 36 °F (2 °C) [147]. The abundance of redosier dogwood in the aboveground forest vegetation was not reported.
The method used to determine seed bank composition may affect findings relative to redosier dogwood. When seeds were extracted from soil samples collected from a 2-year-old clearcut in southern Ontario, researchers estimated that the soil contained 26.1 redosier dogwood seeds/m². However, no redosier dogwood seedlings emerged when soil samples were put in greenhouse and monitored for 5 months. Soil samples included the humus layer and up to 10 cm of mineral soil. Samples were collected in November, and stored at 41 °F (5 °C) for 2 months before being put in the greenhouse [41].
Redosier dogwood seeds are primarily dispersed by birds and mammals. Animal dispersal likely facilitated establishment of redosier dogwood on a landfill reclamation site on Staten Island, New York. Redosier dogwood established naturally within 1 year of reclamation, and the nearest redosier dogwood seed source was 705 feet (215 m) from the site [253].
Many bird species eat redosier dogwood fruits and likely disperse its seed. In New England, redosier dogwood occurred in the diets of 95 bird species (review [196]). In laboratory experiments, viability of redosier dogwood seeds was largely unaffected after consumption by pheasants. More seeds collected from pheasant feces germinated (29%) than seeds that were dried and stored in the laboratory (22%). Stratification increased germination of redosier dogwood seeds collected from pheasant feces [150].
Redosier dogwood seeds were not harmed by consumption by bears, and seeds in bear feces may present an opportunity for secondary dispersal by rodents. In northeastern Minnesota, germination of redosier dogwood was better for redosier dogwood seeds collected from black bear feces (18%) than for unconsumed fresh seeds (7%) (P<0.05). When fresh seeds and seeds collected from bear scat were refrigerated for 50 days before testing, germination of seeds from feces was 22% and for unconsumed seeds was 3% (P<0.01) [254]. In field experiments, researchers found that rodents may be important in the secondary dispersal of redosier dogwood seeds from bear and bird feces, but that secondary dispersal varied among years. Emergence was poorest when redosier dogwood seeds were left in bear feces and was 4 times more likely when seeds were removed from bear feces and planted 5 mm deep. Researchers suggested that unconsumed seeds in deer mice caches would have a better chance of establishing than seeds remaining in bear scat [68].
Redosier dogwood seedlings were commonly found in riparian and forested habitats. Seedlings occurred in open [269] to closed-canopy [264] conditions at riparian sites and disturbed sites. The primary root growth of seedlings is vigorous [22], and seedlings can typically sprout after aboveground damage [221].
Redosier dogwood seedlings occurred at riparian sites in California, North Dakota, and Minnesota. Seedlings occurred beneath semi-open to dense canopies above the water line. Along class 2 streams and their tributaries in the Lassen National Forest in California, redosier dogwood seedlings occurred at sites with relatively dense canopy cover, low light levels, and moderate litter accumulations. Seedlings were limited to sandy soils where stream channels were wide [264]. In cottonwood stands on the floodplains of the Little Missouri River in North Dakota, redosier dogwood shrubs occurred in 9 of 10 stands, and redosier dogwood seedlings occurred in 4 of 10 stands. Cottonwoods in these stands were widely spaced, producing a semi-open canopy [211]. At riparian sites in northern Minnesota, redosier dogwood seedlings established only above the water line, but after "several" years of growth, shrubs survived having their roots and the bases of their stems submerged for most of the growing season [283].
In field experiments, dogwood seedling establishment was best on burned plots when various site treatments were compared in exclosures in Lincoln County, Montana. Seed was planted in the fall of 1949. Emergence was evaluated in June 1950 and was best on burned plots (22.7%) and least on logged plots where slash was scattered (6.4%). Seedling survival to fall 1950 was best on burned plots (60%) and least on logged plots with scattered slash (23.6%). Germination and survival were intermediate on scarified and undisturbed plots [269]. Time since disturbance in the seeding area was not reported. Although this study did not specify the dogwood species used in seeding trials, a later Lincoln County publication suggests it was redosier dogwood [227].
Redosier dogwood seedlings were rarely killed by simulated rodent damage in field experiments in northeastern Alberta. Partial girdling of the stems is the most common type of damage to woody seedlings by meadow voles. Girdling was simulated by removing sections of seedling bark at levels of 0%, 25%, 50% and 75% of the circumference of redosier dogwood stems. Seedlings commonly died back to the point of injury and sprouted new growth below that point. Survival was 100% with no girdling and with half of the stem girdled. Seedling survival was 93% when 75% of the stem was girdled. Although survival was largely unaffected by girdling, redosier dogwood seedling growth was significantly reduced by stem damage (P<0.05) [221].
In greenhouse experiments, redosier dogwood seedlings growing in saturated conditions survived better than seedlings growing in well-drained conditions. Moisture levels maintained in the greenhouse were designed to mimic the relatively dry and wet conditions of forested peatlands in central New York. Mortality of redosier dogwood seedlings in well-drained soils was 57.1% and in saturated conditions was 14.3%. Seedling shoot length and biomass were slightly but not significantly greater in well-drained than saturated conditions [59].
Plant growth: Reviews are in agreement that redosier dogwood grows rapidly, but estimates of the life span of shrubs ranged from short to moderate to long [101,196,291]. Shrub growth can be modified by climate and light. When root and shoot growth was evaluated in the greehouse for 40 days at soil temperatures ranging from 39 to 99 °F (4-37 °C), redosier dogwood root growth was best at 63 °F (17 °C) and shoot growth was best at 79 to 84 °F (26-29 °C). Roots and shoots grew least at 99 °F (37 °C) [17]. Redosier dogwood clones collected from 21 sites ranging as far north as Alaska and as far south as Colorado and grown in a common garden had average growth rates of 11.5 inches (29.1 cm)/plant/day for clones collected from areas with warm climates and 1.7 inches (4.4 cm)/plant/day for clones from areas with cool climates. In growth chamber experiments, all clones were able to acclimate to temperatures much lower than would ever be experienced in nature [281]. Field observations from the Montreal area of southwestern Quebec suggest that the redosier dogwood growth form is phenotypically plastic and controlled by light availability. Beneath an open canopy, redosier dogwood shrubs grew as true upright shrubs but beneath a closed canopy, shrubs were low growing and prostrate [46].
Site characteristics: Throughout its range, redosier dogwood is most common or abundant in moist to wet areas such as shorelines [271], meadows [255], floodplains [312], marshes [282], swamps, bogs [235], and fens [318]. However, it also occurs in forests, woodlands, shrub thickets, and sand dunes [139,235,282,286,312,318].
In many areas, redosier dogwood is more common on floodplains and moist valley bottoms than on upland sites. It occurs throughout British Columbia but is most abundant in broad river valleys at low elevations [94]. In the Vancouver Forest Region, redosier dogwood was characteristic of active floodplain ecosystems in submontane to montane zones [142]. In eastern Washington, it was primarily found at riparian and wetland sites, rarely in the uplands [146]. In western Oregon and northern California, it occurred significantly more often in streamside environments than on hill slopes (P=0.004) [267]. In giant sequoia (Sequoiadendron giganteum) groves on the west slope of the Sierra Nevada, redosier dogwood was restricted to riparian areas [262].
Site indicator value: In western North America and the Great Lakes region, redosier dogwood is an indicator species. In British Columbia, redosier dogwood indicated very moist to wet, nitrogen-rich soils, and friable forest floors [143]. In the Vancouver Forest Region, it was characteristic of active floodplain sites in submontane to montane vegetation where soils were moist to wet with moderate to very high levels of nutrients [89]. In the western Sierra Nevada, redosier dogwood was an indicator species for the California red fir (Abies magnifica) riparian dominance type [104]. Along the South Fork of the Snake River, redosier dogwood indicated moist sites within cottonwood (Populus spp.) stands [190]. The Bureau of Land Management in Montana considered it a facultative or obligate wetland species and used it as a key species in riparian inventory and monitoring [209]. In eastern Montana, redosier dogwood was a mesic forest indicator in upland hardwood stands [163]. In the southern boreal forest regions of Manitoba and Saskatchewan, presence of redosier dogwood was a good indication of very moist sites [257]. At Candle Lake, in central Saskatchewan, redosier dogwood was an indicator of very eutrophic, very moist, and basic (pH 7-7.9) peatlands in boreal forests [129]. In the Lake Agassiz Peatlands Natural Area of Minnesota, redosier dogwood was generally characteristic of peatlands with a pH of 5.8 to 7 that received minerotrophic waters [109].
Climate: Redosier dogwood is widespread in boreal, temperate, and cool mesothermal climates [143] and hardy in USDA zones 2 to 7 [230]. Redosier dogwood is not particularly drought tolerant [190] and, in upland sites, is generally restricted to or most conspicuous in areas receiving more than 20 inches (510 mm) of precipitation annually [196]. However, in propagation and restoration studies, redosier dogwood showed "extreme" drought tolerance once established [19].
Redosier dogwood can survive extremely cold temperatures [230], but in the Alaskan taiga, it is restricted to warm sites [311]. Pellett [224] reported in the Journal of Aboriculture that when actively growing, redosier dogwood may be killed by temperatures just a few degrees below freezing, but when fully acclimated, it survived severe mid-winter temperatures without injury. In a common garden experiment, redosier dogwood clones were collected from sites where the growing season ranged from 90 to 255 days, minimum temperature exposure ranged from -66 to 3 °F (-54 to -16 °C), and altitudes ranged from 12 to 7,000 feet (4-2,100 m). In laboratory studies, all redosier dogwood clones acclimated to temperatures much lower than would ever be experienced in nature (-130 °F (-90 °C)). The average growth rate of clones collected from areas with warm climates was 11.5 inch (29.1 cm)/plant/day, and for clones collected from areas with cool climates was 1.7 inch (4.4 cm)/plant/day [281].
Local climates in redosier dogwood habitats were described from the western and Great Lakes regions of the United States. In western Washington, redosier dogwood was considered a dominant species in western hemlock-western redcedar (Tsuga heterophylla-Thuja plicata) forests in the eastern Cascade Range but was not listed as a dominant in forest types in the western or central Cascades. The eastern Cascades received less precipitation and winter snow, experienced more severe summer droughts, and had more strongly contrasting seasonal temperatures and diurnal temperatures than the western and central regions [60]. In eastern Washington, redosier dogwood occurred primarily in riparian and wetland sites in warm, relatively wide valleys at low to moderate elevations where annual precipitation ranged from less than 20 inches (510 mm) to more than 100 inches (250 mm) [146]. Field observations in Michigan indicated that redosier dogwood was most typical of sites with high levels of moisture and light and moderate levels of heat and nutrients [35]. In New Brunswick, redosier dogwood was the characteristic shrub in western hemlock and white spruce (Picea glauca) forest communities occurring at high-elevation sites where precipitation levels were high, temperatures were low, and growing seasons were short [252].
Elevation: Throughout North America, redosier dogwood is generally found at elevations between 1,500 and 10,000 feet (500-3,000 m) [196]. In British Columbia, occurrence of redosier dogwood decreased with increasing elevation [143]. In seral shrub communities within the western hemlock-western redcedar zone in northern Idaho, frequency of redosier dogwood was significantly greater at low- to mid-slope positions (7-8%) than at high-slope positions (1%) (P<0.05) [201].
Local elevation ranges for redosier dogwood reported in the United States and Canada Arizona Mostly 5,000-9,000 feet (1,500-2,700 m) [138,165] California <9,200 feet (2,800 m) [112,207,266] Colorado 4,500-10,000 feet (1,400-3,000 m) [103] Nevada 4,500-8,900 feet (1,400-2,700 m) [137] New Mexico 5,500-9,000 feet (1,700-2,700 m), from foothills to subalpine regions [43,165,175] New YorkSoils: Redosier dogwood grows best in rich, moist, poorly drained soils with high levels of nutrients, but it tolerates a wide range of soil conditions [230], ranging from moderately acidic to alkaline with moderate to high nutrient levels [35,101]. In the Adirondack Uplands of New York, redosier dogwood occurred on sites with limestone, gneiss, and anorthosite parent materials [151]. At the Crystal Lake Experimental Farm in Iowa, redosier dogwood survived well when planted on peat and calcareous muck soils [181]. In shrub carr vegetation around White Clay Lake, Wisconsin, the distribution of redosier dogwood was not related to soil type and redosier dogwood was considered a poor indicator of soil conditions [132].
Redosier dogwood was most common at sites with rich alkaline soils in Nova Scotia [255] but was somewhat intolerant of alkaline soils in the southwestern United States [313]. In Wisconsin, the most productive redosier dogwood stands occurred where soil pH ranged from 5.5 to 7.5 and the minimum organic matter and silt and clay contents were 1.2% and 7%, respectively (measured at 1 to 2.5 feet (0.3-0.8 m) deep) [328]. In the northern Great Lakes region, redosier dogwood was most commonly associated with minerotrohpic peatlands (also referred to as iron-rich fens) where soil pH typically ranged from 6 to 7.5 [28]. In Newfoundland, redosier dogwood occurred at wet sites with high to very high nutrient contents [186]. Based on field observations in Michigan, redosier dogwood was most typical of sites with high levels of moisture and moderate levels of nutrients [35]. In Alberta's boreal mixedwoods ecoregion, the white spruce (Picea glauca)/redosier dogwood/wild sarsaparilla (Aralia nudicaulis) vegetation association occurred on moderately well to poorly drained Orthic Gleysols with high levels of nutrients [65]. In the sub-boreal spruce zone near Prince George, British Columbia, redosier dogwood had a narrow amplitude with respect to soil nutrient conditions and was generally restricted to sites with relatively high rates of exchangeable calcium and magnesium (Wali 1969 cited in [93]).
Soil moisture: Redosier dogwood occupies sites ranging from dry to very wet, but abundance and growth are typically greatest at moist to wet sites. In central Idaho, redosier dogwood occurred in dry to wet grand fir (Abies grandis) and white fir (A. concolor) stands, but cover was greatest in wet stands [78]. In bottomland hardwood forests of western Montana, redosier dogwood was most common at the wettest sites [75]. In a survey of farmers and ranchers in Montana and North Dakota, those who irrigated their windbreaks ranked redosier dogwood's performance significantly higher than respondents that did not irrigate (P≤0.05) [305]. In Manitoba's Riding Mountain National Park, abundance of redosier dogwood peaked in bur oak (Quercus macrocarpa) forest stands with intermediate moisture levels when a dry to wet gradient was evaluated [331]. In northeastern Illinois, frequency of redosier dogwood was greatest in hydric sedge (Carex spp.) and cattail (Typha ssp.) marshes with very poor drainage and a water table at or near the soil surface. Redosier dogwood also occurred in hydric calcareous fens, wet-mesic calcareous seeps, and sedge meadows with poor to imperfect drainage [32]. In a survey of 102 boreal conifer-hardwood stands in the Great Lakes region, redosier dogwood was present in 9 stands characterized as dry and 14 stands characterized as wet [178]. When poorly drained and better drained speckled alder (Alnus incana subsp. rugosa) swamps were compared at the Dunbar Forest Experiment Station in Michigan, total aboveground biomass of redosier dogwood was greatest at the better drained site with very fine sandy loam soils and least at the poorly drained site with silty clay loam soils [220]. In the Haut-Saint-Laurent region of Quebec, redosier dogwood shrublands occurred on flat upland sites with poor to very poor drainage but were not highly associated with any parent material [188].
Riparian habitats: Characteristics of riparian sites occupied by redosier dogwood range from low- to steep-gradient stream types with fine to coarse-textured soils. In British Columbia, redosier dogwood was most abundant at low elevations in broad river valleys with gleyed or regosolic soils (review by [94]). In the sub-boreal spruce zone in the Prince Rupert Forest Region, redosier dogwood was characteristic of and often dominated cottonwood (Populus spp.) bottomland communities along rivers and streams with wide, meandering floodplains [234]. In the National Forests of eastern Washington, redosier dogwood was an understory dominant in forests and woodlands along low- to moderate-gradient streams that generally occurred in wide valley areas. Characteristics of riparian sites dominated by redosier dogwood shrublands ranged from steep-gradient streams with high sediment transport potential to low-gradient, highly sinuous streams with well-developed floodplains [146]. In central Idaho, the water birch (Betula occidentalis)/red-osier dogwood riparian association occurred along steep-gradient stream types with coarse-textured soils [119], and the gray alder (Alnus incana)-redosier dogwood tall shrub community type occurred in narrow, low-elevation canyons along the Salmon River and its tributaries where soils were excessively drained to somewhat poorly drained [302]. In eastern Idaho and western Wyoming, redosier dogwood was dominant in riparian community types on coarse-textured soils with at least 35% rock and water table depths of 20 to 38 inches (51-97 cm) [334]. The redosier dogwood shrubland type in western Montana was most common adjacent to moderate- to high-gradient rivers with poorly developed, coarse-textured soils [99]. In eastern Nevada, redosier dogwood was most common along Type 3 streams that drained alluvial landforms and had wide valley floors [280].
Flood tolerance: Redosier dogwood is tolerant of scouring and flooding [174]. An extension bulletin from Utah suggests that redosier dogwood shrubs prefer wet soils with good drainage and tolerate standing water for short periods [291], and a review of revegetation and reclamation guides indicates that growing season flooding is tolerated [101]. In the only study that directly evaluated flooded sites for an extended period, redosier dogwood survived and was "hardy" after 7 years of water above root crown level in permanently flooded sites created by construction of locks and dams along the Upper Mississippi River [90]. In British Columbia, redosier dogwood occurred on regularly flooded sites and tolerated fluctuating water tables [20,143]. The redosier dogwood shrubland type in western Montana also tolerated prolonged flooding and variable water table depths, which experienced large seasonal fluctuations [99]. When the Fraser, Nooksack, Skagit, and Columbia rivers reached the highest flood stage seen in over 50 years in the Pacific Northwest, redosier dogwood "suffered little more than chlorosis" [37].
Plant communities: Redosier dogwood occurs in a variety of forest, woodland, shrubland, and grassland community types along streams, in canyons or ravines, or near marshes, springs, or other wet areas. It is recognized as an understory dominant in many riparian forest, woodland, and shrubland types (see Table 1).
Forests and woodlands: Redosier dogwood is noted as an understory species in western, central, and eastern forest cover types of the United States and Canada.
Western forest types include:Alaska and Western Canada: Redosier dogwood is common in forests and woodlands throughout Alaska and western Canada. In Alaska, an open to dense redosier dogwood shrub layer occurred with balsam poplar and black cottonwood in cold deciduous forests on bottomland sites in the Yukon and Kuskokwim drainages [210]. In British Columbia, redosier dogwood was often dominant in alluvial floodplain forests [143]. In the northern part of the Province, redosier dogwood occurred within the boreal white and black spruce zone, sub-boreal spruce (Picea spp.) zone, and sub-boreal pine (Pinus spp.)–spruce zone but was absent from the northern portion of the Engelmann spruce–subalpine fir (Picea engelmannii-Abies lasiocarpa) zone [20]. In the Vancouver Forest Region, redosier dogwood was characteristic of submontane to montane, active floodplain ecosystems, which often support productive stands of black cottonwood, western redcedar, and Sitka spruce (P. sitchensis) [142]. Redosier dogwood was also common in the shrub layer of aspen parkland communities, particularly in moist locations occurring between the Great Plains grasslands and northern coniferous forests of western Canada [26]. In central Alberta, redosier dogwood was common in seral cottonwood stands, with a frequency of 95% in balsam poplar, 75% in balsam poplar-quaking aspen, and 65% in quaking aspen stands. Redosier dogwood was described as occasional to frequent in climax white spruce forests [199].
Great Basin, California, and Southwest: Redosier dogwood was associated with several riparian forest and woodland types in the southwestern United States. In the southern portion of the Snake Range in eastern Nevada, it was the dominant shrub in a mixed community type with riparian species such as narrowleaf cottonwood (Populus angustifolia) and narrowleaf willow (Salix exigua) and upland species such as singleleaf pinyon (Pinus monophylla), big sagebrush (Artemisia tridentata), and rubber rabbitbrush (Chrysothamnus nauseosus) [280]. On the western slope of the Sierra Nevada in California, redosier dogwood was restricted to riparian sites in giant sequoia (Sequoiadendron giganteum) groves [262]. In Arizona and New Mexico, redosier dogwood was common in ponderosa pine (P. ponderosa) and Douglas-fir (Pseudotsuga menziesii) stands [165].
Northern Rockies and Northern Great Plains: Redosier dogwood was particularly common in cottonwood-dominated riparian communities in the northern Rockies and Great Plains. When cottonwood stands were surveyed on the South Fork of the Snake River, narrowleaf cottonwood/redosier dogwood community types were most common in depressions and swales with fine-textured soils and high moisture levels [190]. In the southern part of the Bob Marshall Wilderness in Montana, redosier dogwood cover was relatively high in the black cottonwood floodplain vegetation type [172]. When researchers studied wooded draws near the Matador Research Station in southern Saskatchewan, average redosier dogwood cover was greatest (15%) in the Bebb willow (Salix bebbiana) woodland type, which was restricted to narrow gravel stream channels [162]. However at Candle Lake, in the central part of the Province, redosier dogwood did not show specificity to any tree canopy type, occurring in the understory of tree-age and sapling-age forests dominated by balsam poplar (Populus balsamifera), quaking aspen, paper birch (Betula papyrifera), white spruce, black spruce, and balsam fir [63]. In the quaking aspen-paper birch community type in McKenzie County, North Dakota, redosier dogwood dominated the shrub layer on extremely mesic north-facing slopes near springs. Density of redosier dogwood was as high as 16,872 stems/ha [83]. In the Badlands of North Dakota, redosier dogwood was most common in cottonwood woodlands largely restricted to the floodplains of the Little Missouri River and less common in Rocky Mountain juniper (Juniperus scopulorum) and green ash (Fraxinus pennsylvanica) woodlands [211].
Great Lakes and Eastern Canada: Several woodland and forest types have redosier dogwood as a common shrub layer component in the Great Lakes and eastern Canada. In the Rainy River section of the Great Lakes-St. Lawrence Forest region, redosier dogwood was a dominant shrub in 3 community types: the mesotrophic, moist, redosier dogwood-beaked hazelnut-arctic sweet coltsfoot (Corylus cornuta-Petasites frigidus) type on glacial soils with white spruce and hardwoods in the canopy; the eutrophic, very fresh, redosier dogwood-beaked hazelnut-arctic sweet coltsfoot type on alluvial soils with primarily aspen and ash (Fraxinus spp.) in the canopy; and the eutrophic, wet, redosier dogwood/hairy sedge-yellow marsh marigold (Carex lacustris-Caltha palustris) type on mineral soils with tamarack, aspen, and black spruce in the canopy [203]. In New Brunswick, redosier dogwood occurred in bur oak forests at meadow and shoreline sites [184] and in northern whitecedar-alder/hylocomium moss (Alnus spp./Hylocomium umbratum) and white spruce/naked miterwort/western oakfern (Mitella nuda/Gymnocarpium dryopteris) forest communities at high-elevation sites experiencing high levels of precipitation, low temperatures, and short growing seasons [252].
Shrublands: Redosier dogwood is a dominant in many shrubland types associated with streams, marshes, and other wet sites throughout its range. In southeast Alaska, redosier dogwood was scattered in clacareous fens [180]. In Sacramento Valley, California, redosier dogwood occurred in shrub thickets with buttonbush (Cephalanthus occidentalis) and Pacific dewberry (Rubus vitifolius) on the upper-elevation hummocks of freshwater marshes [49]. Along subalpine streams and other wetlands above 8,500 feet (2,600 m) in Arizona, redosier dogwood was locally common in boreal riparian scrub communities dominated by willows and was particularly important at downstream locations where conditions approached cold temperate [39]. Redosier dogwood was listed among the principal woody species together with Rocky Mountain maple (Acer glabrum), chokecherry (Prunus virginiana), and Scouler willow (Salix scouleriana) in the riparian community type at the Curlew National Grasslands in Idaho [48]. In Wisconsin, redosier dogwood presence values were greater in southern shrub carr vegetation than in any other community [54]. When 76 shrub carr stands were evaluated in 13 counties in southeastern Wisconsin, redosier dogwood occurred in 88% of stands; shrub carr stands dominated by redosier dogwood averaged 7.9 feet (2.4 m) tall [327]. In Tompkins County, New York, redosier dogwood sometimes dominated swamp shrub vegetation surrounding herbaceous marshes [121].
Grasslands: In many parts of its range, redosier dogwood frequently establishes in herbaceous communities when they experience at least a short period without disturbance. In the Kamloops Forest Region of British Columbia, redosier dogwood occurred at wet sites within the bluebunch wheatgrass (Pseudoroegneria spicata) zone [166]. In southeastern Wisconsin, redosier dogwood was an "early invader" of sedge (Carex spp.) tussock meadows. The shrub-dominated stage of succession initiated by establishment of redosier dogwood was slowed or restricted by grazing [51]. In a survey of prairies, savannas, and wetlands in natural areas in northeastern Illinois, frequency of redosier dogwood was greatest in a hydric, poorly drained, marsh community dominated by sedges and cattails with a water table at or near the soil surface. Redosier dogwood was also found in calcareous fens, calcareous seeps, and sedge meadows considered hydric to wet-mesic with poor to imperfect drainage [32].
Table 1. Location and type of plant communities in which redosier dogwood was a dominant species Community Type Location Forests Blue spruce (Picea pungens)/redosier dogwood habitat type At sites with water sources on the Cibola National Forest in New Mexico [5], and along streams and wet draws in northern New Mexico, northern Arizona, and southern Colorado [161] Blue spruce/Saskatoon serviceberry (Amelanchier alnifolia)-redosier dogwood/elk sedge (Carex geyeri) habitat type Along streams and in valley bottoms of the White River National Forest in Colorado [111,322]Sitka spruce/redosier dogwood/American skunkcabbage (Lysichiton americanus) seasonally flooded riparian type
Along large coastal rivers in northwestern Oregon [179] Engelmann spruce/redosier dogwood cold riparian forest type Blue Mountain region of southeastern Washington and northeastern Oregon [237] and in eastern Washington [146]White spruce/redosier dogwood/wild sarsaparilla (Aralia nudicaulis) vegetation association
In the boreal mixedwoods ecoregion in Alberta [65] and on recent alluvium at low-elevation, wet, rich sites in west-central Alberta [50]Black spruce/prickly rose (Rosa acicularis)-swamp red currant (Ribes triste)-redosier dogwood/bigleaf aster (Eurybia macrophylla)-red baneberry (Actaea rubra) forest type
Great Lakes region [153] Spruce/redosier dogwood riparian type Eastern Idaho, western Wyoming [334], and Montana [100] Ponderosa pine/redosier dogwood riparian community type Montana Douglas-fir/redosier dogwood riparian community type Montana [100] Western hemlock-western redcedar/redosier dogwood/queencup beadlily (Clintonia uniflora) forest Within the eastern region of the Cascade Mountains in Washington [60] Conifer/redosier dogwood riparian community type In the Humboldt and Toiyabe National Forests in Nevada and eastern California [174] and in southern Idaho and Utah [218] Woodlands Boxelder (Acer negundo)/redosier dogwood riparian type Southern Idaho and Utah [218] Gray alder/redosier dogwood riparian type Nevada [212], southern Idaho, and Utah [218] Water birch/redosier dogwood riparian community type Eastern California [174], Nevada [212], Idaho [119,218], Wyoming [320], and Utah [218] Black ash-mixed hardwood-conifer/redosier dogwood/sedge community type Manitoba, North Dakota, Minnesota [270], Michigan, Illinois, and Ontario [294] Rocky Mountain juniper/redosier dogwood riparian community type Montana [100] Narrowleaf cottonwood-(blue spruce)/thinleaf alder (Alnus incana subsp. tenuifolia)-redosier dogwood riparian vegetation association Within the montane forest zone in western Colorado (average cover of redosier dogwood: 24.8%) [15] Narrowleaf cottonwood/redosier dogwood riparian community type Eastern California [174], Nevada [212], eastern Idaho, western Wyoming [334], Montana [100], southern Idaho, and Utah [218] Narrowleaf cottonwood/thinleaf alder-redosier dogwood community type In narrow valleys on well-drained sandy to fine loam soils in north-central New Mexico[204] Black cottonwood (Populus balsamifera subsp. trichocarpa)-Engelmann spruce/mountain alder (Alnus viridis subsp. crispa)-redosier dogwood type Along Cherry Creek on sandy skeletal soils with spring flooding in the Winema National Forest in Oregon [145] Black cottonwood/redosier dogwood/taperfruit shortscale sedgeSee the Fire Regime Table for a list of plant communities in which redosier dogwood may occur and information on the FIRE REGIMES associated with those communities.
Redosier dogwood is typically present throughout all stages of succession, but abundance is often greater in earlier than later stages. Similarly, redosier dogwood occupies open sites and occurs beneath closed canopies, but abundance is typically greater in sun than shade.
Shade relationships: Redosier dogwood is shade tolerant but generally grows best at intermediate to high light levels. Cover and size of redosier dogwood are often greater in open stands or canopy gaps than beneath heavily shaded canopies, but redosier dogwood persists and may be abundant in dense shade. In the western hemlock-western redcedar zone of northern Idaho, frequency of redosier dogwood was 1% to 7% where tree canopy cover ranged from 0% to 55%. Redosier dogwood was extremely rare where tree canopy cover exceeded 55% [201]. In Bird's Hill Provincial Park in southern Manitoba, redosier dogwood was more common in the openings than in closed-canopy black spruce forests [290]. Redosier dogwood was significantly more abundant (P<0.0005) in coniferous forests where canopy openness averaged 90% than where canopy openness averaged 27.5% in the Montreal area of southwestern Quebec [46]. In Tompkins County, New York, redosier dogwood was frequent and abundant in canopy gaps resulting from mortality of American elm and rare in closed-canopy forests [122]. In north-central Minnesota, dogwoods (alternate-leaf dogwood, roundleaf dogwood (Cornus rugosa), and redosier dogwood) were most abundant in forests with a moderate density of canopy trees. Dogwood abundance was less in areas with low or high canopy tree densities [216]. In another study in northern Minnesota, redosier dogwood was described as "suppressed and scattered" in dense shade but "conspicuous and more abundant" in sunnier spots [283]. In cottonwood forests on the South Fork of the Snake River in Idaho, redosier dogwood cover was high on sites with dense narrowleaf cottonwood, and its shade tolerance was considered very high [190].
Redosier dogwood grew best under higher light conditions when cuttings from a single clone were rooted in February and planted outdoors in May beneath shade screens that produced 100%, 75%, 53% and 27% full sunlight. Fresh stem and leaf weight were highest in plants grown in 75% full sunlight. Redosier dogwood plants produced significantly more inflorescences in the 2 highest light conditions than in the 2 lowest light conditions (P<0.05). Characteristics of the cuttings were evaluated in October and are summarized below [272]:
Characteristics of redosier dogwood plants grown at increasing shade levels [272] Light (%) 100 75 53 27 Fresh stem weight (g) 155ab 198c 162b 131a Fresh leaf weight (g) 201b 234c 190b 142a Number of inflorescences 7.2b 6.2b 3.5a 3.0a Values within a row followed by different letters are significantly different (P<0.05).Primary succession: Redosier dogwood has appeared early in the succession on bare sand deposits in the eastern United States. In the past, when the Hudson estuary was dredged to widen the channel, large amounts of sand and mud were deposited at shallow sites along the Hudson River. Redosier dogwood appeared by 1945, on deposits made between 1929 and 1937 in Columbia County, New York [185]. Redosier dogwood also occurred on dredge spoils from the Seneca Canal in upstate New York within 2 years of deposition [193].
Hydrosere succession: Redosier dogwood is common in the mid-seral, shrub-dominated stage of hydrosere succession on several sites in Wisconsin and in the Lake Agassiz area of Manitoba. In the peatlands of Dane County, standing water is first colonized by submerged vegetation, then floating reed swamps develop. Broadleaf cattail (Typha latifolia) and bulrush (Scirpus spp.) establish in shallow waters and constantly saturated soils, and sedge-meadows dominated by bluejoint reedgrass (Calamagrostis canadensis) and sedges develop where the spring and early summer water tables are at or just above the soil surface. Once established, sedge-meadows that remain undisturbed are colonized by woody vegetation. Two years without mowing or burning in the sedge-meadow allows for establishment of densely shading shrubs. Willow shrubs establish first and increase in abundance most rapidly. Redosier dogwood is slower to establish but increases its dominance through stolon growth. Undisturbed shrublands are eventually colonized by cottonwood and willow trees. Redosier dogwood persists in the understory and openings of these deciduous forests [79]. Redosier dogwood was considered the most important shrub species in southern shrub carr vegetation that followed the sedge-meadow community in primary hydrosere succession. Trees invaded the shrub carr slowly; in 20-year-old shrublands, trees were still largely restricted to the periphery [54]. In sedge-meadows where mowing was recently discontinued, redosier dogwood establishment was delayed; it dominated the terminal stages of shrub carr development. Redosier dogwood abundance gradually decreased as deciduous forest canopies developed [327]. In the glacial Lake Agassiz area, prairie communities developed during the hydrarch succession of wet flats and swamps left by glacial recession, and redosier dogwood was common in brush-prairie vegetation occurring in succession between prairie and deciduous forest. Its persistence in "climax" deciduous forests was unclear because no climax forests occurred in the study area [69].
Secondary succession: Redosier dogwood tolerates disturbance and generally appears early in postdisturbance succession of shrublands, floodplains, forests, and old fields. Abundance of redosier dogwood is often greater many years after disturbance than immediately following disturbance. When 76 shrub carr stands were evaluated in 13 counties in southeastern Wisconsin, redosier dogwood occurred in 88% of stands. Most shrublands had been burned, grazed, mowed, flooded, or drained in the last 30 years. Redosier dogwood was particularly common in stands that had been undisturbed for 10 to 35 years [327].
Floodplain and riparian succession: Redosier dogwood generally occurs throughout all stages of floodplain and riparian forest succession. While redosier dogwood establishment is common on new floodplain deposits, abundance may be greatest in mid-seral habitats. Along floodplains of the Tanana River in Alaska, researchers evaluated vegetation changes from stage 1 with establishment of willows on newly deposited alluvium to stage 12 with dominance by black spruce forest. Redosier dogwood established in stage 5, on 20- to 40-year-old floodplain terraces with an open balsam poplar canopy and a dense alder understory. Redosier dogwood was also reported in stage 6, on 80- to 100-year-old terraces with a closed balsam poplar canopy. Redosier dogwood's persistence in mature and climax vegetation was not evaluated [310]. On the Willamette River in northwestern Oregon, redosier dogwood was most common (61% frequency) in the understory of mid- to late-seral black cottonwood forests, which were 39 years old and more than 65 years old, respectively [73]. In aspen parklands of central Canada, redosier dogwood typically established on the mud banks and sand bars along large swiftly moving rivers. Redosier dogwood also occurred in the understory of mature quaking aspen stands [25].
In the western United States, redosier dogwood may dominate early-, mid-, or late-seral riparian communities. In southwestern Idaho, the redosier dogwood shrubland type is considered an early-seral community along streams or rivers [198]. In eastern Idaho and western Wyoming, the redosier dogwood/sweetscented bedstraw riparian vegetation type is considered early seral, and the spruce/redosier dogwood type is considered mid-seral. Successional change proceeds very slowly in these communities [334]. In southeastern Idaho and Utah, the redosier dogwood/common cowparsnip riparian community is an early-seral type along streams where rocky material has been deposited and highly aerated water moves through the coarse soils. The narrowleaf cottonwood/redosier dogwood community is an early- to mid-seral riparian type above elevations of 7,300 feet (2,200 m). The boxelder/redosier dogwood riparian community is a stable type where successional change proceeds slowly. The gray alder/redosier dogwood type occurs along streams with seasonal scouring and deposition, but when stream channels remain unchanged and undisturbed the late-seral conifer/redosier dogwood community develops and dominates [218]. In Montana, redosier dogwood is a dominant in several mid- and late-seral riparian vegetation types. The mid-seral narrowleaf cottonwood/redosier dogwood type in the absence of deposition and flooding may develop into the late-seral ponderosa pine/redosier dogwood, Rocky Mountain juniper/redosier dogwood, or Douglas-fir/redosier dogwood types at low-elevation sites or late-seral spruce/redosier dogwood forests at high-elevation sites [100].
Forest succession: While redosier dogwood is often present in forest vegetation immediately following canopy-opening disturbances, its abundance generally increases with time since disturbance in early succession. In Washington, redosier dogwood was present in the "devastation" area left after the eruption of Mount St Helens, which included blowdown, scorched, debris flow, pyroclastic flow, and/or mud flow areas [187]. Around Brule Lake in the Athabasca River valley in central Alberta, advancing sand dunes often smother spruce forest vegetation. Redosier dogwood persists in the sand dune area and may dominate sands through rapid stolon growth [64]. In the Bitterroot Mountains of northern Idaho, redosier dogwood often occurred on moist sites within the first 2 to 3 years after fire in mixed-conifer forests [159]. In the subalpine forest zone of the Flathead National Forest, Montana, redosier dogwood cover was greater on sites burned 35 to 70 years prior than on old-growth sites unburned for 100 years or more [336]. In southeastern Manitoba, redosier dogwood occurred in boreal mixedwood stands that were burned, logged, or budworm infested 10 to 16 years earlier. Redosier dogwood cover and frequency were greatest in logged stands (5.3% and 10%, respectively) [140].
When tamarack forests in the peatlands of Dane County, Wisconsin, were logged, redosier dogwood occurred as scattered individuals in the logged area but increased in abundance in the absence of another disturbance. Poison sumac (Toxicodendron vernix)-redosier dogwood and willow-redosier dogwood shrublands dominated early postlogging succession [79]. In northeastern Ontario, redosier dogwood was more common in logged than undisturbed black spruce stands, but cover was low (<2%) in either case [42]. When redosier dogwood cover was compared at the edge of clearcuts and in interior parts of aspen-dominated boreal forests in Alberta, cover of redosier dogwood was significantly greater at the edges of 16-year-old clearcuts than within the forests. Cover was significantly lower at 1-year-old clearcut edges than witihin forests (P<0.05), and differences were not significant between forest interiors and 5-year-old clearcut edges [102].
Redosier dogwood growth after canopy-opening disturbances may limit conifer regeneration. A review reports that redosier dogwood may limit conifer regeneration on subhygric to hydric sites [94]. In the Vancouver Forest Region of British Columbia, redosier dogwood was considered a "vigorously competing" species on clearcut sites within the interior cedar-hemlock zone [142]. In the Prince Rupert Forest region of British Columbia, the mid-seral quaking aspen-paper birch/redosier dogwood community occurred at mesic to subhygric low-elevation sites. Succession to the climax conifer-dominated vegetation type was thought to be slowed by heavy shrub and herb undergrowth [95]. In southwestern Quebec, tree seedlings were lacking beneath but found beyond redosier dogwood shrub canopies in powerline rights of way. Beneath powerlines, density of redosier dogwood was over 100,000 stems/ha. Researchers suggested planting redosier dogwood in rights of way to biologically control forest succession [189].
Browsing: Heavy browsing can reduce redosier dogwood abundance in shrublands and forests and can limit establishment and spread of redosier dogwood in herbaceous communities. Several studies indicate that redosier dogwood is sensitive to repeated heavy browsing [4,183,190,196]. In cottonwood stands along the Yellowstone River in Montana, redosier dogwood dominated the shrub layer on relatively ungrazed sites, but with moderate cattle use, abundance and cover of redosier dogwood was reduced. With heavy cattle use, redosier dogwood and other shrubs may be eliminated and nonnative grasses may dominate the understory [29]. This same pattern was described for ponderosa pine/redosier dogwood, Douglas-fir/redosier dogwood, and aspen/redosier dogwood stands throughout Montana [100]. In Wind Cave National Park, southwestern South Dakota, an unpublished survey by Smith cited in [248] suggests that redosier dogwood is restricted to inaccessible and secluded areas of the park because of intense utilization by ungulates. Intense browsing levels coincided with the removal of large carnivores from the area according to a retrospective study by Ripple and Beschta [248]. Redosier dogwood was nearly extirpated from Anticosti Island, Quebec, by severe white-tailed deer browsing. Deer populations remained high (>20 deer/km²) after their introduction about 100 years earlier [273]. On Isle Royale, comparisons of moose-browsed and protected areas indicate that abundance of redosier dogwood was often lower in browsed than unbrowsed areas [149,249]. In southeastern Wisconsin, redosier dogwood establishment and spread in sedge tussock meadows was slowed when tussock vegetation was grazed [51]. In sedge meadow vegetation at Lodi Marsh in southern Wisconsin, redosier dogwood abundance increased with the removal of grazing. Meadows were heavily grazed by cattle for at least 70 years, until 1977 when some plots were protected. In 1977, redosier dogwood cover was close to 0% in the meadow, although many small redosier dogwood seedlings were present. By 1997 redosier cover had increased to 9% in protected plots (P<0.0001). The sedge meadow transitioned to a shrub carr community within 20 years of cattle removal [191].
Old-field succession: In very recently abandoned fields, redosier dogwood is generally rare, but abundance typically increases with time since abandonment. A study of the first 25 years of old-field succession in Washtenaw County, Michigan, reported that the shrub-dominated stage of succession, where redosier dogwood may be common, appears as early as 6 to 10 years after abandonment of cultivated fields such as corn, soybeans, and potatoes; it may appear later (11 to 15 years) after abandonment of small grain and hay fields. Generally, the shrub-dominated stage persists for 20 or more years [21]. In an old field at the University of Toledo's Flanigan Farm in Ohio, redosier dogwood first appeared 3 years after abandonment. At one side of the former agricultural field was an overgrown hedgerow with redosier dogwood and other shrubs. As many as 2 redosier dogwood plants/m² were found during sampling of the 3-year old field [301]. On the Piedmont Plateau of Somerset County, New Jersey, redosier dogwood occurred but was rare in 2-year-old fields. In this area, redosier dogwood also occurred in 5-, 10-, 15-, 25-, and 40-year-old fields and in oak-dominated climax forests at least 250 years old. Abundance of redosier dogwood was greatest in 25-year-old fields, where almost 64% of the fields were occupied by immature trees and shrubs [16].
The scientific name of redosier dogwood is Cornus sericea L. (Cornaceae) [84,112,136,324]. There are 2 subspecies:
Cornus sericea L. subsp. occidentalis (Torr. & A. Gray) Fosberg [76,112,136]
Cornus sericea L. subsp. sericea L. [112,136]
Hybrids:
Redosier dogwood may hybridize with alternate-leaf dogwood (C. alternifolia) where distributions overlap [246].
Because of its tolerance of wet soils, rapid establishment and growth, and potentially extensive rooting of prostrate stems, redosier dogwood is often recommended for stream bank revegetation and erosion control [99,115,167]. It is also a useful choice in regevetation because of its ability to shade streams and provide structural diversity for wildlife and birds [174].
Redosier dogwood may also be useful in the revegetation of roadside cuts and mine sites. Survival of redosier dogwood was 94% in the 4th year after bareroot stock was spring planted on a roadside cut in the Coram Experimental Forest in northwestern Montana [126]. In a greenhouse study, redosier dogwood survived and was resistant to short-term exposure to consolidated tailings collected from a holding pond at an oil sand mine site [242]. In another greenhouse study, redosier dogwood seedlings tolerated salinity concentrations of up to 50 mM. High salinity levels are characteristic of oil sand mine tailings [243]. On amended Athabasca oil sand tailings, redosier dogwood was listed among the species with the most variable survival rates (0-89%) [72].
Vegetative spread and regeneration are important to the persistence of redosier dogwood. Redosier dogwood spreads and regenerates vegetatively by stolons, layering, and root crown sprouts (review by [230]). Shrub size commonly increases through the rooting of prostrate stems and lower branches [103,107,312]. Several authors indicate that vegetative spread and regeneration in redosier dogwood is from stolons ([64,79,230,318,327], Geisler 1985 personal communication cited in [93]). However, the prostrate rooting stems and lower branches important for vegetative spread of redosier dogwood may not be true "differentiated stolons" [245]. Two authors suggest that redosier dogwood spreads and propagates by rapidly growing rhizomes [64,157], but most of the available literature makes no reference to rhizomes in redosier dogwood.
Increases in redosier dogwood shrub size and area occupied are commonly facilitated by stolon growth. Stolons can extend as far as 10 feet (3 m) from the parent plant (Geisler 1985 personal communication cited in [93]). Stoloniferous growth is common in sand dune habitats [318]. In central Alberta, redosier dogwood survives burial from advancing sand dunes on the northeast coast of Brule Lake through rapidly growing stolons [64]. In shrub carr vegetation in southeastern Wisconsin, stolons may be important in the development of large-sized shrubs but not necessarily large stands. Individual redosier dogwood shrubs occurred as easily distinguishable, multi-stemmed clumps. Stems within a shrub clump were connected by stolons, but shrubs were not connected to one another by stolons. Of 186 redosier dogwood shrubs in 9 stands, the average number of stems/shrub was 18.3, and the canopy diameter of shrubs averaged 4.1 feet (1.3 m) [327].
Sprouting: Redosier dogwood can regenerate by sprouting from buried stem pieces and from the root crown of top-killed shrubs. Redosier dogwood stem pieces collected from a mid-seral, boreal mixedwood forest near Lac La Biche, Alberta, sprouted only when planted in September. Only stem pieces 6 inches (15 cm) and 12 inches (30 cm) long sprouted; 4-inch (10 cm) stem pieces failed to sprout. Stem pieces planted in the forest understory in June, July, and August failed to sprout, regardless of their size [157].
Redosier dogwood sprouts from the root crow following top-kill or damage from fire or cutting. For more information on postfire sprouting, see Plant response to fire. In quaking aspen-mixed hardwood stands in the Chippewa National Forest in Minnesota, redosier dogwood shrubs survived 6 consecutive years of cutting [226]. At Utah State University's Farmington Research Farm, 4-year-old redosier dogwood shrubs were compared with and without cutting treatments, which involved removal of all stems to within 0.5 foot (0.15 m) of the root crown. Stems were cut prior to or at the time of bud break. New shoots sprouted from the root crown of all cut shrubs. Cut shrubs regrew to the height of uncut shrubs in each of 2 consecutive years of cutting; however, the total crown area of cut redosier dogwood shrubs was significantly less than that of uncut shrubs [263].
Cornus sericea, the red osier or red-osier dogwood,[2] is a species of flowering plant in the family Cornaceae, native to much of North America. It has sometimes been considered a synonym of the Asian species Cornus alba. Other names include red brush, red willow,[3][4][5] redstem dogwood,[3][5] redtwig dogwood, red-rood, American dogwood,[3] creek dogwood, and western dogwood.[3]
In the wild, it most commonly grows in areas of rich, poorly drained soils, such as riparian zones and wetlands, or in upland areas which receive more than 20 inches of precipitation annually. More uncommonly, it may be found in drier zones albeit at lesser abundance. Red osier dogwood is tolerant of flooding and has been known to survive up to seven years of water above root crown level. It occurs from sea level to 10,000 feet (3,000m), but in many areas is most common above 1,500 feet.[6]
It is a medium to tall deciduous shrub, growing 1.5–4 m tall and 3–5 m wide, spreading readily by underground stolons to form dense thickets. The branches and twigs are dark red, although wild plants may lack this coloration in shaded areas.
The leaves are opposite, 5–12 cm long and 2.5–6 cm broad, with an ovate to oblong shape and an entire margin; they are dark green above and glaucous below; fall color is commonly bright red to purple. Like all dogwoods, they have characteristic stringy white piths within the leaf stalks, which can be used for identification.[7]
The flowers are small (5–10 mm diameter), flat, umbella-like and dull white, in clusters 3–6 cm diameter.
The fruit is a globose white berry 5–9 mm diameter.
The Latin specific epithet sericea means "silky", referring to the texture of the leaves.[8]
Red osier dogwood provides food and cover for many species of mammals and birds. The stems and especially new shoots are browsed by moose, elk, bighorn sheep, mountain goats, beavers, and rabbits, while the fruits are an important autumn food source for bears, small mammals, and 47 different bird species. In winter, red osier dogwood is heavily browsed by ungulates; in some areas use exceeds availability and individuals which have not been browsed are rare. The shrub is also important for nesting habitat and cover for a great variety of animals.[6]
Cornus sericea is shade tolerant but prefers intermediate to high light levels. It tolerates disturbance well, and appears early in both primary and secondary succession throughout its native range, but especially in floodplains and riparian zones. It thrives in fire-disturbed sites, sprouting from seeds or damaged shrubs.[6]
Although its conservation status is overall secure, it is considered vulnerable in Iowa and critically imperiled in Kentucky and Virginia.[1]
Cornus sericea is a popular ornamental shrub that is often planted for the red coloring of its twigs in the dormant season. The cultivars 'Bud's Yellow',[9] 'Flaviramea'[10] with lime green stems, and 'Hedgerows Gold'[11] (variegated foliage) have gained the Royal Horticultural Society's Award of Garden Merit (confirmed 2017).[12]
Like most dogwood species native to North America, C. sericea can be parasitized by the dogwood sawfly, possibly leaving much of the plant devoid of leaves. A variety of pesticides are effective; however, hand-picking the larvae is also an option.
Cornus sericea is frequently used for waterway bank erosion protection and restoration in the United States and Canada. Its root system provides excellent soil retention, it is hardy and provides an attractive shrub even when bare in winter, and its ability to be reproduced by cuttings makes it a low-cost solution for large-scale plantings.[13][14]
Some Plateau Indigenous tribes ate the berries to treat colds and to slow bleeding.[15][16]
Known as cansasa in Lakota, the inner bark was also used by the Lakota and other Native Americans as "traditional tobacco", either by itself or in a mixture with other plant materials.[17][18] Among the Algonquian peoples such as the Ojibwe, the smoking mixtures, known as kinnikinnick, blended the inner bark with tobacco,[4] while more western tribes added it to the bearberry leaf to improve the taste.[15][19]
The Ojibwe used red-osier dogwood bark as a dye by taking the inner bark and mixing it with other plants or minerals.[3]
The withies, or osiers, are used in basketry.
It is a variable species, with two subspecies commonly accepted:
It is native throughout boreal and temperate zones in northern and western North America from Alaska east to Newfoundland, south to Durango and Nuevo León in the west, and Illinois and Virginia in the east.
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shrub, fall
shrub, winter
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twig and leaf
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Cornus: specimen botanicum sistens descriptiones et icones specierum corni minus cognitarum
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Cornus sericea, the red osier or red-osier dogwood, is a species of flowering plant in the family Cornaceae, native to much of North America. It has sometimes been considered a synonym of the Asian species Cornus alba. Other names include red brush, red willow, redstem dogwood, redtwig dogwood, red-rood, American dogwood, creek dogwood, and western dogwood.
