More info for the terms: climax, cover, density, eruption, frequency, fresh, marsh, mesic, shrub, shrubs, stolon, succession, tree, tussock
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% . In Bird's Hill Provincial Park in southern Manitoba, redosier dogwood was more common in the openings than in closed-canopy black spruce forests . 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 . 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 . 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 . 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 . 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 .
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 :
|Characteristics of redosier dogwood plants grown at increasing shade levels |
|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 . Redosier dogwood also occurred on dredge spoils from the Seneca Canal in upstate New York within 2 years of deposition .
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 . 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 . 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 . 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 .
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 .
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 . 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 . 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 .
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 . 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 . 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 . 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 .
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 . 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 . 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 . 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 . 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) .
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 . In northeastern Ontario, redosier dogwood was more common in logged than undisturbed black spruce stands, but cover was low (<2%) in either case . 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 .
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 . 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 . 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 . 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 .
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 . This same pattern was described for ponderosa pine/redosier dogwood, Douglas-fir/redosier dogwood, and aspen/redosier dogwood stands throughout Montana . In Wind Cave National Park, southwestern South Dakota, an unpublished survey by Smith cited in  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 . 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 . 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 . 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 .
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 . 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 . 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 .
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