More info for the terms: association, bryophytes, cover, density, duff, frequency, importance value, lichens, litter, prescribed fire, rhizome, root crown, series, shrub, shrubs, succession, top-kill, tree, vine, wildfire
FIRE ADAPTATIONS AND PLANT RESPONSE TO FIRE: Red elderberry sprouts from the root crown and/or rhizomes after top-kill by fire ([25,26,165,171,215], Newton 1984, personal communication cited in [102]). Not all red elderberry populations are rhizomatous (see Belowground description), so postfire rhizome sprouting will not occur on all sites.
Red elderberry may establish after fire from on-site seed stored in litter [107] or soil [100,107,108,109,216] or from off-site seed. Red elderberry seeds in the seed bank may begin germinating the spring after fire (see Regeneration Processes and Seasonal Development) [25,26,208]. Because red elderberry seed is animal dispersed, postfire establishment from off-site seed sources is likely; however, animal dispersal onto burns was not well documented in the literature as of 2008. A year after the severe Sundance Wildfire in northern Idaho, red elderberry seedlings and root crown sprouts on study sites had 3% cover and 4% frequency (seedling and root crown sprout data were pooled) [213].
Red elderberry does not often gain dominance after fire; it typically remains a minor component of the vegetation on sites where it occurred in low numbers before fire (for example, [164]). However, postfire seedling emergence may be "extensive" on some sites [25,26,208].
Many studies show red elderberry is favored but not greatly enhanced by fire [102,106,110,152,181,183,212,246]. In western Montana, red elderberry attained minor coverage (0.2-0.3%) 2 years after both the Miller Creek prescribed fire on the Flathead National Forest and the Newman Ridge prescribed fire on the Lolo National Forest. Red elderberry was not present on study sites before the fires [212], suggesting that it established from on- or off-site seed, not sprouts. After spring wildfires in a sugar maple-eastern hemlock-American beech forest in south-central New York, red elderberry saplings reestablished from sprouts but had the lowest importance value (2.5) of all woody species present [221]. Red elderberry had 0.3% cover 35 years after a wildfire in a red spruce-Fraser fir (Picea rubens-Abies fraseri) forest in North Carolina. Its density at postfire year 35 was estimated at 1,364 stems/ha [206]. In chronosequence studies in New Brunswick, red elderberry was present in jack pine and mixed-hardwood forests that developed 7 to 20 years after stand-replacing fires. Red elderberry was present in mostly trace amounts. Its cover (3%) and frequency (3%) were greatest in 10-year-old burns [167].
On many sites, a combination of fire and other treatments may have little effect on red elderberry abundance.
Logging and burning: After clearcutting and slash burning in subalpine fir-western larch-Engelmann spruce (Larix occidentalis-Picea engelmannii) stands on the Flathead National Forest, Montana, red elderberry had a nonsignificant, 5.6% mean decrease in frequency compared to unburned stands. Time-since-fire on study sites ranged from 2 to 15 years [237].
Red elderberry responses to winter clearcutting and slash burning were similar in studies on the Clearwater, MacKenzie, and Headwaters Forest Districts of south-central, central interior, and east-central British Columbia, respectively. All sites were logged when snow was deep enough to prevent disturbance to understory vegetation or the forest floor [108,109,111]. On the Clearwater Forest District, red elderberry established from on-site seed after winter clearcutting of an Engelmann spruce-subalpine fir forest followed by spring or fall slash burning, with red elderberry frequency consistently higher in burned than in unburned plots (P<0.01). Red elderberry cover was generally low. In postfire year 2, a flush of postfire red elderberry germination resulted in greater cover on burned than unburned plots (P>0.04); otherwise, there were no significant differences in cover between treatments. Many germinants on burned plots did not survive. Postfire sprouting of top-killed red elderberry was observed but not quantified [111]. See the Research Project Summary of the Clearwater study for further details on the postfire response of red elderberry and 33 other plant species.
Mean percent cover (and frequency) of red elderberry before and after clearcutting and slash burning on the Clearwater Forest District of British Columbia [111] Forest District Before logging and fire Postfire year 1 2 3 5 10 spring fire 0 (0) 1 (70) 4 (75) 1.7 (80) 2.4 (65) 1.2 (60) fall fire 0 (0) 0.1 (53) 3.7 (47) 1.3 (53) 1 (40) 0.7 (27) unburned 0.4 (7) 1.4 (14) 1.4 (7) 2.1 (7) 0.7 (7) 0.4 (7)
The MacKenzie and Headwaters sites were burned the summer following winter cutting. Over 10 years, red elderberry decreased slightly in cover but increased greatly in frequency over prefire values on the MacKenzie site, which was in a hybrid spruce/devil's club (P. glauca à P. engelmannii/Oplopanax horridus) forest [108]. Prefire abundance was not measured on the Headwaters site, a subalpine fir-hybrid spruce/big huckleberry forest. Red elderberry cover increased over 3 postfire years on the Headwaters site. Frequency remained stable over that period, but had decreased by postfire year 10 compared to postfire years 1 to 5 [109]. See the Research Paper of the MacKenzie study for further details on the postfire responses of red elderberry, other vascular plant species, and bryophytes.
Mean percent cover (and frequency) of red elderberry after clearcutting and slash burning on the MacKenzie [108] and Headwaters [109] Forest Districts of British Columbia Forest District After logging;
before fire Postfire year 1 2 3 5 10 MacKenzie 0.50 (17) 7.17 (100) 16.33 (100) 3.17 (100) 0.78 (83) 0.38 (100) Headwaters not available 0.08 (83.3) 1.27 (83.3) 2.25 (83.3) 1.83 (100) 0.20 (50)
Herbicides and burning: Roberts [200] reported that red elderberry seedlings were "present but not abundant" 4 months after August application of picloram followed by a September prescribed fire in a red alder community on the Coast Ranges of Oregon. Red elderberry sprouting also occurred, with means of 13 inches (32 cm) for clump height, 10 inches (26 cm) for clump diameter, and 6 stems/clump for clump density at postfire month 3.5 (n=4) [200]. In the Prince George Forest District of east-central British Columbia, red elderberry established from soil-stored seed after winter clearcutting, August slash burning, and May replanting of a subalpine fir/devil's club forest. On plots where fire exposed mineral soil, red elderberry increased in the first 3 postfire years, then declined in postfire years 5 and 10. On plots where some litter and duff remained after burning, cover and frequency peaked in postfire year 1. Across postfire years 1 through 10, red elderberry was less frequent on mineral soil than on forest floor plots [107].
Mean percent cover (and frequency) of red elderberry after clearcutting and slash burning in British Columbia [107] Substrate Prefire Postfire year 1 2 3 5 10 Mineral soil (n=19 plots) not applicable 2.90 (47.37) 7.01 (63.16) 3.21 (47.37) 1.59 (47.37) 1.70 (36.84) Forest floor (n=128 plots) 0.09 (1.56) 15.07 (89.84) 10.70 (87.50) 3.68 (71.88) 1.50 (60.16) 0.48 (39.06)
See the Research Paper of Hamilton's [107] study for information on the responses of over 100 vascular plants, mosses, and lichens to the logging and prescribed fire treatments.
In a vine maple (Acer circinatum)-salmonberry shrubfield in coastal central Oregon, September herbicide (glyphosate) and October prescribed fire treatments reduced red elderberry cover over pretreatment levels in the short term, while September use of herbicide alone increased red elderberry cover over pretreatment levels. Red elderberries not killed by the treatments sprouted from their root crowns. Treatments were undertaken to convert the shrubfield to a conifer plantation [142].
Mean red elderberry cover (%) before and after treatments in an Oregon shrubfield [142] Treatment Pretreatment Posttreatment year 1 Herbicide and fire 20 5 Herbicide 15 20
In a study on the Siuslaw National Forest in coastal Oregon, red elderberries on north-facing slopes recovered after combined tree harvest, spray-and-burn, and repeat spray treatments, while red elderberries on south-facing slopes were apparently favored by cutting and/or fire but killed by the second spraying. Study sites were on a Douglas-fir plantation that had been clearcut in late winter and early spring, sprayed with 2,4-D and 2,4,5-T in July, broadcast burned in September, replanted to Douglas-fir in February, and resprayed with 2,4-D and 2,4,5-T three years after the broadcast burn [210].
Mean red elderberry cover (%) after clearcutting, herbicide spraying, and burning on the Siuslaw National Forest, Oregon [210] North aspect South aspect Postspray month 1 (1 month prefire) 0.05 0 Postfire year 1 0.01 0.02 Postfire year 3 1.00 0.07 Postfire year 4; 1 year after 2nd spraying 0.06 0
Red elderberry may dominate early postfire vegetation on some sites. In a chronosequence study in north-central Idaho, red elderberry was among the most abundant shrub species on logged and broadcast-burned grand fir/Oregon boxwood (Paxistima myrsinites) sites on 1-, 3-, and 8-year-old burned sites. It was 1 of 5 or 6 shrubs showing largest canopy volumes on 3- and 8-year-old burns. Red elderberry regenerated primarily by sprouting. Postfire stands dominated by red elderberry were on steep, northwest-facing slopes at the highest-elevation (5,100-5,300 feet (1,555-1,615 m)) grand fir/Oregon boxwood sites. Red elderberry canopy volume and height across different-aged stands were [249]:
Mean canopy volume and height of red elderberry on clearcut-and-broadcast burned grand fir/Oregon boxwood sites in Idaho [249] Postfire year 1 Postfire year 3 Postfire year 8 Postfire year 12 Postfire year 23 Canopy volume* 0.5 1.2 2.5 0.8 not given Height (cm) 18 53 94 94 98 *Percent plant volume in a 1 Ã 1 Ã 3 m plot.
Lyon [163] reported an increase in red elderberry density after an August prescribed fire in south-central Idaho. The site was on "less disturbed terrain" within a heavily logged Douglas-fir forest. He attributed the increase in red elderberry density to multiple stems sprouting from the root crowns of formerly single-stemmed red elderberry plants. Prefire abundance of red elderberry was not quantified, but 2 years after the fire red elderberry had the 3rd largest crown volume of 12 shrub species [163]. See Lyon's Research Paper on this study for further information on the fire and the postfire responses of 64 plant species.
Mean red elderberry density and crown volume after prescribed fire in Idaho [163] Postfire year 1 Postfire year 2 Density (plants/1,000 feet²) 0.02 0.74 Crown volume (feet³) 0.3 27.9
Browsing: Protection from browsing will likely increase red elderberry postfire abundance on burned areas with large ungulate populations. In a sugar maple-American beech forest in the Adirondack Mountains of New York, red elderberry showed rapid growth after prescribed fall burning and postfire exclusion of white-tailed deer. Five years after treatments, red elderberry had attained heights up to 10 feet (3 m) in exclosures. On burned plots where white-tailed deer were not excluded, red elderberry was ≤3 feet (1 m) tall. White-tailed deer density was approximately 27 individuals/mile² in the area [19].
Frequent repeated fire: Limited studies suggest that repeated fire generally favors red elderberry [23,187], although some report red elderberry decreases after repeated fires [25,26,208]. Repeated fires generally promote red elderberry and other sprouting shrub species over conifers and fire-sensitive shrubs such as Oregon boxwood. On the Tillamook Burn of northwestern Oregon, red elderberry was not present on unburned plots but had 2% frequency on burned plots. At the time of the study, the burned plots had experienced 3 stand-replacing wildfires in 12 years. Overall, sprouting shrub species were more common in burned than unburned plots [187]. A series of prescribed fires to increase moose browse on the Chugach National Forest of southeastern Alaska slightly reduced red elderberry cover below prefire levels. Fifteen to 19 years after the fires, mean postfire coverage of red elderberry on 3 quaking aspen-balsam poplar (Populus tremuloides-P. balsamifera subsp. trichocarpa) sites was 3% compared to prefire coverage of 5% [23].
Severe fire: Based on limited studies, red elderberry shows no clear pattern of response to severe fires. Red elderberry sprouted "prolifically" the year after an explosion in a gasoline pipeline ignited a "severe" wildfire in a black cottonwood-red alder forest on Whatcom Creek, Washington [86]. It showed variable responses after severe fires in northeastern Oregon. Reestablishment was slow after a wildfire in a grand fir/queencup beadlily association near the John Day River. Red elderberry was not present on severely burned plots 1 year after the fire. It increased to 1% cover by postfire year 5. A severe wildfire near Twin Lakes, however, apparently promoted red elderberry. The fire burned through a plot established in a subalpine fir/Carolina bugbane (Trautvetteria caroliniensis) forest a year before. Red elderberry cover was 1% before the fire and 5% in postfire year 1 [133].
Late postfire succession: Since red elderberry tolerates shade (see Successional status), it may persist in late-seral postfire succession. Red elderberry was "occasionally found" on a 55-year-old burn in Yellowstone National Park [224]. In a chronosequence study in subboreal hybrid spruce/devil's club forests of British Columbia, red elderberry was a common species on 14-, 50- to 80-, and 140+-year-old burns [75].
