More info for the terms: association, basal area, cover, fern, fire regime, forbs, frequency, fresh, hardwood, importance value, litter, mesic, organic soils, presence, relative frequency, serpentine soils, shrub, succession, ultramafic soils
Site characteristics: Thimbleberry is most common in mesic forests and riparian areas [99,100,134,236]. In subboreal conifer-hardwood forests in the Great Lakes region, thimbleberry was absent from dry sites but occurred with 4% frequency on dry-mesic, 18% on mesic, 4% on wet-mesic, and 3% on wet sites. Balsam fir (Abies balsamea) and sugar maple (Acer saccharum) dominated the mesic sites [149]. In arid habitats and ecosystems, thimbleberry is typically restricted to riparian sites (e.g., [78,209,239]).
Thimbleberry is most typical of upper floodplain sites with limited flooding or lower sites with rapidly draining soils. Along riparian sites in 2nd-growth forests in the central Cascade Range of Washington, importance value for thimbleberry was 20 on low floodplains, 24 on high floodplains, 4 on terraces, and 0 on hilltops. Generally low floodplains were inundated at least every 2 years; high floodplains were inundated less frequently but at less than 50-year intervals. Terraces were above the 100-year flood stage. (Importance values were the sum of relative cover and relative frequency divided by 2 [230]). In northwestern Oregon, thimbleberry occurred at 0 to 3 feet (1 m) above the high water line of streams on shallow cobbly silts or sands and at 2 to 10 feet (0.6-3 m) above the high water line of rivers on deep, gravelly sands [151].On 144 riparian plots in the Lake Tahoe Basin near the California-Nevada border, thimbleberry was most commonly associated with highly sinuous streams in wide valleys and rare along V-shaped, high-gradient streams [157].
Climate: Thimbleberry occurs in areas with a variety of climates. In western Oregon, thimbleberry is common in coastal regions generally free of frost, and in Wisconsin and northern Michigan, it is common at sites with prolonged freezing winter temperatures and abundant snow [248]. In Washington's Gifford Pinchot National Forest, grand fir (Abies grandis)/thimbleberry forests occurred on cool moist sites with substantial snow packs. However, thimbleberry was a poor site indicator species because it was also found—although rarely as a dominant and often confined to stream sides and seeps—in warm, moderately dry grand fir forests, warm, moist western redcedar (Thuja plicata) forests, and hot, dry, low-elevation Douglas-fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa) forests [222]. In British Columbia, thimbleberry occurred in areas with boreal, temperate, and mesothermal climates, but its occurrence generally increased with increasing elevation and increasing continentality [126]. It appears sensitive to extremely cold winters, short growing seasons, and extreme summer moisture stress, and it grows best in moist to wet conditions (review by [81]). However, thimbleberry is also consistently found in interior Douglas-fir communities in British Columbia's Kamloops Forest Region, where the climate is warm and dry, growing seasons are relatively long, and moisture deficits are common [138].
Elevation: Thimbleberry's elevation ranges are described only for its western range. Low elevations are occupied in the northern part of the Pacific Northwest Coast [88,102,181]. Elevations from sea level to subalpine zones are occupied in the southern part of the Coast [181], and elevations above 4,000 feet (1,200 m) are occupied in the Southwest [146,239]. In areas of western Oregon north of Douglas County, thimbleberry occurred in the subalpine zone but was most common at low elevations [222]. In the Siskiyou Mountains of Oregon and California, frequency of thimbleberry was greatest at the 1,500- to 2,500-foot (460-760 m) and 4,500- to 5,500-foot (1,400-1,700 m) elevational ranges [240]. In the western redcedar-western hemlock (Tsuga heterophylla) zone of northern Idaho, thimbleberry's probability of occurrence was greater at low elevations than high elevations, but thimbleberry height growth was greater at high elevations than low elevations [111].
Local elevation ranges for thimbleberry reported in the United States and Canada Arizona 7,000-10,700 feet (2,100-3,200 m) [25,120] California <8,200 feet (2,500 m) [100,171] Colorado 7,000-10,000 feet (2,000-3,000 m) [97] Nevada
4,900-8,200 feet (1,500-2,500 m) [118]
New Mexico
7,000-10,000 feet (2,000-3,000 m) [29,146]
Utah 4,700-9,000 feet (1,400-2,700 m) [239] British Columbia sea level-4,000 feet (1,200 m) [81]
Soils: Thimbleberry grows best in moist, nutrient-rich soils with good drainage but tolerates a wide range of soil conditions. It occupies sites where nutrient levels range from moderate to high and moisture conditions range from relatively dry to wet. Generally, plants are much smaller on dry than moist sites and in poorly drained than rapidly drained soils (review by [81]). In Canada, thimbleberry is considered a nitrophytic shrub (that is, an indicator of nitrogen-rich soils). It is most common in seepage habitats with fresh soils that receive well aerated water. Thimbleberry also grows on wetter and drier sites but typically with reduced size and cover [185]. In coastal British Columbia, thimbleberry is an indicator of nitrogen-rich soils and friable forest floors [126]. In redwood (Sequoia sempervirens) communities of coastal northern California, thimbleberry occupied sites where nutrient levels were moderate and moisture was high [235].
Moderately deep and coarsely textured soils are common in thimbleberry habitats. On the Siuslaw National Forest, Oregon, the western sword fern (Polystichum munitum)-thimbleberry community type was common at sites where soils were typically 12 to 18 inches (30-46 cm) deep and parent materials were primarily basaltic. Cover and frequency of thimbleberry was much lower at sites where soils were very shallow [49]. In the Tillamook burn area of Oregon, the red alder (Alnus rubra)/thimbleberry community type occurred at sites where gravel made up more than 75% of the total soil volume, and the thimbleberry/broadleaf starflower (Trientalis borealis subsp. latifolia) community occurred at sites where basalt gravel made up more than 80% of the total soil volume [14].
Thimbleberry grows on serpentine and other ultramafic soils but may grow better or be more common on soils with lower levels of toxic metals. In the Cascade Range in Washington, thimbleberry was dominant on the east side but less common in the west or central regions. East side habitats had larger ranges in soil pH and organic matter than habitats in the west and central regions. Thimbleberry was most common at mesic, low-elevation sites on nonserpentine sandstone soils [52] but also occurred on serpentine soils, although largely restricted to wet, shady, cool sites. Sandstone soils were less extreme than serpentine soils with respect to moisture and pH [53]. In greenhouse studies, thimbleberry showed no ecotypic growth response to ultramafic soils. Thimbleberry plants and/or seeds collected from both ultramafic and nonultramafic soil sites grew in ultramafic soils [132].
Plant communities: Throughout its range, thimbleberry occurs in shrublands, riparian vegetation, and in deciduous, coniferous, and mixed forests. It can occur in dense, almost pure patches or as scattered individuals [225]. In the plant community descriptions below, those community and habitat types where thimbleberry was recognized as dominant are presented in bold font. See the Fire Regime Table for a list of plant communities in which thimbleberry may occur and information on the FIRE REGIMES associated with those communities.
Shrublands: In the Pacific Northwest, thimbleberry was often dominant in shrublands occurring at ecotones between prairie and forest communities and in early-seral communities following forest disturbances. Thimbleberry was common in coastal shrublands found on cool, low-elevation (<1,200 feet (370 m)) sites between grasslands and forests from Washington to California [16]. These ecotone communities were commonly referred to as coastal headland or islet shrubland communities in Oregon [16,68]. Common associates included salal (Gaultheria shallon), evergreen huckleberry (Vaccinium ovatum), and salmonberry (Rubus spectabilis) [30]. In California, common associates included coyote bush (Baccharis pilularis), blueblossom (Ceanothus thyrsiflorus) and California coffeeberry (Rhamnus californica), and the canopy height reached 15 to 20 feet (5-6 m) tall [16]. The thimbleberry/fireweed (Chamerion angustifolium) mountain meadow community type was most common at elevations below 4,900 feet (1,500 m) in Oregon and Washington [69]. In the western North Cascade Range in Washington, the subalpine thimbleberry/fireweed community type occurred on mesic, well-drained soils on steep south slopes and avalanche tracts. The community type was species rich, with up to 70 species, and it occasionally occupied large areas with vertical distances of 1 to 1.5 miles (1.6-2.4 km) and elevational ranges of 2,000 feet (600 m) [57,58]. On Monument Peak in the western Cascade Range of Oregon, thimbleberry was typical in shrubland ecotones between Douglas-fir and western hemlock forests and rock-fell communities where grasses and forbs occur sporadically in rocky outcrops. Thimbleberry shrublands also occurred at the margins and in clearings within very dense noble fir (Abies procera) forests and were especially common in clearings in Pacific silver fir (A. amabilis)-western hemlock forests [6].
Several thimbleberry communities are recognized in early forest succession. In the Oregon's Tillamook burn area, old-growth Douglas-fir forests burned 3 times in 12 years, and thimbleberry was important in seral communities including the red alder (Alnus rubra)/thimbleberry shrubland on steep north-facing slopes with gravelly soils between 800 and 1,200 feet (240-370 m) and the thimbleberry/broadleaf starflower shrubland on upper slopes and ridgetops with gravelly soils above 1,800 feet (550 m) [14]. On the Siuslaw National Forest, the western sword fern-thimbleberry ecotone community was common between headland prairies and Sitka spruce (Picea sitchensis)-western hemlock forests at sites where soils were primarily of basaltic origin and typically 12 to 18 inches (30-46 cm) deep. The young Sitka spruce in the western sword fern-thimbleberry community suggests the community could represent an early stage of forest succession [49]. In southeastern Alaska, thimbleberry occurred in meadows or in logged areas within western hemlock, Sitka spruce, and western redcedar forests where soil pH generally measured 6 to 7 [220]. In the Nez Perce and Clearwater National Forests of northern Idaho, a Rocky Mountain maple (Acer glabrum)-thimbleberry community often dominated 15 to 20 years after clearcutting and burning in the moist grand fir/wild ginger (Asarum caudatum) habitat type [77]. A thimbleberry shrubland type occurs in Michigan and Ontario. The shrubland occupies gentle to moderate slopes at fairly low elevations (620-750 feet (190-230 m)) and typically appears following burning or clearing. Thimbleberry shrublands are uncommon, which might mean they are rapidly replaced as forest succession progresses [221].
Riparian and wetland vegetation: From southeastern Alaska south to California and east to the Great Lakes, thimbleberry is described in riparian and wetland areas including streambanks [191,220], wet to moist seepage areas [10], and lakeshores [221].
Thimbleberry is recognized as a dominant in several riparian communities. In coastal British Columbia, a Sitka spruce-red alder (Alnus rubra)/thimbleberry community was recognized within the floodplain spruce association on sandy, mesic sites in the Kimsquit River Valley [15]. Although thimbleberry occurred in nearly all biogeoclimatic zones in British Columbia, it was most common on fluvial sites within the western hemlock coastal zone [81]. In northwestern Oregon, the thimbleberry/vanilla-leaf (Achlys triphylla) community was common in shallow, cobbly, streamside silts or sands at 0 to 3 feet (1 m) above the normal high water line. Thimbleberry frequency was 100% in red alder/common snowberry (Symphoricarpos albus)-salmonberry communities in deep, very gravelly, streamside sands occurring 2 to 10 feet (0.6-3 m) above the high water line of the Salmon River [151]. On western slopes of the Sierra Nevada, thimbleberry was an indicator species for white fir (Abies concolor)-dominated riparian vegetation [98]. After surveying 144 riparian plots in the Lake Tahoe Basin near the California-Nevada border, researchers determined that thimbleberry was characteristic of currant-blackberry (Ribes-Rubus spp.) communities, which were associated with wide areas of riparian vegetation along highly sinuous rivers. Currant-blackberry vegetation was least common along V-shaped, high-gradient streams [157].
Forests and woodlands: Thimbleberry is a common understory species in a variety of deciduous, coniferous, and mixed-forest types throughout its range. It may be more abundant beneath partially open canopies or in recently disturbed forests but often persists in mature and closed-canopy forests as well [20,38].
Pacific Northwest: Common overstory associates in thimbleberry habitats in the Pacific Northwest include hemlock (Tsuga spp.), western redcedar, grand fir, Douglas-fir, and red alder [54,181,190]. Although cover and size of thimbleberry may be greatest in partially open to open stands, it also occurs in the closed canopy of young deciduous and mature coniferous forests [20,38,81,190]. In coastal southeastern Alaska, thimbleberry was common in Sitka spruce-western hemlock forests and in Sitka alder (Alnus viridis subsp. sinuata) thickets [229]. In British Columbia, it occurred in nearly all biogeoclimatic zones but was uncommon in extremely cold boreal forests or exceedingly dry ponderosa pine or Douglas-fir forests. Coastal western hemlock, subboreal spruce (Picea spp.), interior western redcedar-western hemlock, montane spruce, and Engelmann spruce-subalpine fir (P. engelmannii-Abies lasiocarpa) forests on base-rich sites with subhygric to hygric, well-aerated soils were common thimbleberry habitats [38]. On the Gifford Pinchot National Forest, thimbleberry was an understory dominant in grand fir/thimbleberry/drops-of-gold (Prosartes hookeri var. hookeri) forest types on cool, moist sites receiving substantial snowfall [222]. In the central Cascade Range in Washington, importance of thimbleberry increased from west to east, and thimbleberry was a dominant in the following eastside communities:
- western redcedar/thimbleberry/queencup beadlily/field horsetail (Clintonia uniflora/Equisetum arvense)
- grand fir-western redcedar/Rocky Mountain maple/thimbleberry
- grand fir/white spirea-Oregon boxwood (Spiraea betulifolia-Pachistima myrsinites)/thimbleberry
- grand fir-subalpine fir/Oregon boxwood/thimbleberry [54,55]
Although thimbleberry occurred in all plant associations recognized from the western to eastern parts of Washington's Columbia River Gorge, it was most widespread and had the greatest cover in cool, moist Douglas-fir and western redcedar forests. Thimbleberry was restricted to ravine or riparian sites in more eastern parts of the gorge dominated by ponderosa pine, Oregon white oak (Quercus garryana), manzanita (Arctostaphylos spp.), big sagebrush (Artemisia tridentata), or cheatgrass (Bromus tectorum) [243]. In the Blue Mountains of Oregon, a quaking aspen (Populus tremuloides)/thimbleberry-western bracken fern-starry Solomon's-seal (Pteridium aquilinum-Smilacina stellata) community type occurred on moist sites above the Imnaha River. This type was considered seral to grand fir forests [218]. In northeastern Oregon and southeastern Washington, thimbleberry was a major species within the ponderosa pine zone at 4,900- to 6,600-foot (1,500-2,000 m) sites receiving 25 to 45 inches (640-1,100 mm) of annual precipitation [33].
Interior Northwest: Thimbleberry communities and associates in the Interior West are similar to and nearly as diverse as those described in the Pacific Northwest. In Waterton Lakes National Park in Alberta, white spruce (Picea glauca)/thimbleberry montane forest types occupied hygric to mesic sites [1]. Thimbleberry was also reported as an understory species in montane Douglas-fir forests and quaking aspen woodlands in southwestern Alberta [166]. Thimbleberry was widespread in northern Idaho and occurred with 90% frequency in western redcedar/menziesia (Menziesia ferruginea)/wild ginger habitat types [178] and 80% of stands in the western redcedar-western hemlock zone [48]. In central Idaho, thimbleberry occurred in early-seral to late-seral grand fir/Rocky Mountain maple habitat types [207] and was characteristic of late-seral Douglas-fir habitat types [208]. In Montana's Glacier National Park and Whitefish Mountains, thimbleberry dominated the understory of Engelmann spruce-subalpine fir forests [47]. Quaking aspen woodlands were common thimbleberry habitat in South Dakota, Wyoming, and Colorado. Quaking aspen/thimbleberry communities occurred at 5,600 feet (1,700 m) on limestone soils in the Black Hills of South Dakota [198] and Wyoming [36].
California and Southwest: Thimbleberry was often described in redwood stands in California [142], quaking aspen woodlands in Nevada, Utah, and Colorado [118,170,194], and subalpine fir forests in Arizona and New Mexico [66]. A redwood-Sitka spruce/thimbleberry vegetation association was described at the Headwaters Forest Reserve in central Humboldt County (Jimersson and Jones 2000 cited in [143]). In giant sequoia (Sequoiadendron giganteum) groves of the Sierra Nevada, thimbleberry development was best in riparian areas, but thimbleberry was not restricted to them. In terms of canopy cover, white fir was the dominant trees species within the groves. Giant sequoias contributed less than 5% canopy cover but occupied the largest basal area [191]. In redwood/red alder/salmonberry communities in northwestern California, thimbleberry cover was low (3%) but frequency was high (90%) [142]. Throughout California, as far south as San Diego County, thimbleberry can be found in canyons and canopy openings in mixed-conifer and white fir forests below 7,900 feet (2,400 m) [39].
Intermountain West: In the Intermountain West, the quaking aspen/thimbleberry community type occurred at fairly high-elevation sites (8,000-9,300 feet (2,400-2,800 m)), and although not especially common, the type occupied large areas within Bridger-Teton, Caribou-Targhee, Wasatch-Cache, and Uinta National Forests [170]. On the western side of the Rocky Mountains in central Colorado, thimbleberry occurred in quaking aspen groves on gentle slopes and narrowleaf cottonwood (Populus angustifolia) groves in valleys and canyons [194]. The subalpine fir/dwarf bilberry (Vaccinium myrtillus)-thimbleberry habitat type occurred at cool moist sites on steep north slopes at elevations of 8,800-9,800 feet (2,700-3,000 m) in the San Juan Mountains of southern Colorado and northern New Mexico [56]. The subalpine fir (Abies lasiocarpa var. lasiocarpa)/thimbleberry forest type occurred at high-elevation sites in central and southern Arizona and southern New Mexico [169,216]. The subalpine fir/thimbleberry habitat occurred on cobbly soils on moist, protected, west, north, or east slopes with minimal growing-season water stress [137,162].
Great Lakes: Thimbleberry occurs in subboreal forests, northern hardwood forests, and mixed forests in the Great Lakes region. In Wisconsin, thimbleberry's presence was greater in subboreal forests than other plant communities [46]. However, thimbleberry was also found beneath the "dense shadows" of yellow birch (Betula alleghaniensis), eastern hemlock (Tsuga canadensis), maples (Acer spp.), and American beech (Fagus grandifolia) (Chamberlin 1877 cited in [45]). On the Apostle Islands, the maximum frequency of thimbleberry was 40% in stands dominated by sugar maple, paper birch (B. papyrifera), or northern red oak (Q. rubra) [19]. In Michigan, thimbleberry thickets were common in northern hardwood forests and moist mixed-forest communities and especially common at forest or woodland borders and clearings near the Great Lakes [232]. On the Keweenaw Peninsula of northern Michigan, thimbleberry was the only shrub species found in all 4 upland balsam fir-white spruce and balsam fir-white spruce-hardwood (sugar maple dominated) stands. When sites ranging from wet-mesic to dry-mesic were compared, thimbleberry was most frequent on mesic sites [149,150].
Thimbleberry was also found in several other Great Lakes forest types. These types, their distribution, and site characteristics are briefly described in the table below.
Thimbleberry was noted as the most common or abundant short shrub in the following forests and woodlands near the Great Lakes [221]:
Forest or woodland type Region Site characteristics Eastern white pine (Pinus strobus)-quaking aspen/beaked hazelnut (Corylus cornuta subsp. cornuta) forest n MN, n WI, n MI, and nw ON on dry-mesic to mesic, rapidly drained fine sands to loams Northern whitecedar (Thuja occidentalis)/balsam fir-mountain maple (A. spicatum) n MN, n WI, n MI, and nw ON on gentle to steep slopes, 620-910 feet (190-280 m), on calcareous sandy loams Northern whitecedar-yellow birch forest n MN, n WI, n MI, and ON on poorly drained, lowland, organic soils and gentle to somewhat steep northern slopes; soils typically acidic sandy clays with thin litter layer White spruce-balsam fir-quaking aspen/mixed herbs forest* n MN, n MI, n WI, and nw ON up to 1,300 feet (400 m), on deep, well drained to rapidly drained but moist, fine-textured, mineral soils White spruce/poverty oatgrass (Danthonia spicata) forest with paper birch MI and ON at up to 1,250 feet (380 m), on well drained to rapidly drained sandy or sandy loam organics Paper birch/bush-honeysuckle (Diervilla lonicera) woodland with balsam fir n MN, n MI, and ON on gentle to steep slopes, 620-864 feet (190-260 m), on coarse loams or sandy loams; noncalcareous mineral soil, which can be very shallow (6 inches (<15 cm)) in ON Quaking aspen-balsam poplar (Populus balsamifera)-mixed-hardwoods lowland forest n WI, MI, and ON on deep, fresh to moist, well to poorly drained soils, often fine-textured and of lacustrine origin Quaking aspen-paper birch woodlands with balsam fir and white spruce n MN, n MI, n WI, and ON on deep, well drained to rapidly drained mineral soils, usually loams but can be clays, silts, or sands Quaking aspen-paper birch/sugar maple-mixed-hardwoods woodland n MN, w upper MI, n WI, and nw ON on rich mesic sites with clay or silt loams Yellow birch woodland with sugar maple and white spruce n MI and ON at 630-780 feet (190-240 m), on moderately well drained to rapidly drained sandy loams *Thimbleberry is indicator species for open forest variant type.