Index of Species Information

SPECIES:  Vaccinium myrtilloides


SPECIES: Vaccinium myrtilloides
AUTHORSHIP AND CITATION : Tirmenstein, D. 1990. Vaccinium myrtilloides. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: [].

ABBREVIATION : VACMYT SYNONYMS : Vaccinium canadense Vaccinium angustifolium var. integrifolium Vaccinium pennsylvanicum var. myrtilloides Vaccinium angustifolium var. myrtilloides Cyanococcus canadensis SCS PLANT CODE : VAMY COMMON NAMES : velvetleaf blueberry TAXONOMY : The currently accepted scientific name of velvetleaf blueberry is Vaccinium myrtilloides Michx. (Ericaceae) [41]. The following forms, distinguished primarily on the basis of fruit color, have been identified [3,66,90]: forma chicoccum (Deane) Fernald - (white fruit) forma myrtilloides - (blue fruit with bloom) Velvetleaf blueberry hybridizes with a number of species including sweet hurts blueberry (V. boreale), hillside blueberry (V. pallidum), Darrow's evergreen blueberry (V. darrowii), small cluster blueberry (V. tenellum), downy blueberry (V. atrococcum), V. vacillans, and low sweet blueberry (V. angustifolium) [1,10,22,32,78,87]. Naturally occurring velvetleaf blueberry-sweet hurts blueberry hybrids are particularly common and produce populations or "hybrid complexes" which exhibit numerous intermediate characteristics [32,78]. In the past, much taxonomic confusion has surrounded the relationship between velvetleaf blueberry and low sweet blueberry. Velvetleaf blueberry was formerly considered a variety of low sweet blueberry [90]. Plants of intermediate characteristics, which were once delineated as Vaccinium angustifolium var. integrifolium (synonym var. hypolasium), are now considered natural hybrids produced from a velvetleaf blueberry-low sweet blueberry cross [33,78,90]. LIFE FORM : Shrub FEDERAL LEGAL STATUS : No special status OTHER STATUS : Velvetleaf blueberry is tentatively listed by Washington as critically imnperiled (S1?) in that state [103]. In Montana, velvetleaf blueberry has been found in only one location near West Glacier. It is, however, widespread in neighboring Alberta [55]. Velvetleaf blueberry was formerly believed to be extirpated from Ohio, but several populations were found in 1984 [17].


SPECIES: Vaccinium myrtilloides
GENERAL DISTRIBUTION : Velvetleaf blueberry grows from central Labrador across Canada to British Columbia and the Northwest Territories [90]. In eastern North America, it extends southward through the mountains of New England, New York, and Pennsylvania to West Virginia and Virginia [78,80,86]. Disjunct populations have been reported in the uplands of the Appalachian Mountains [88]. Velvetleaf blueberry is also common in the upper Midwest and Lake States [80]. Evidence suggests that this now transcontinental species [43], was formerly restricted to the central Arctic at the end of the Tertiary [78]. ECOSYSTEMS : FRES10 White - red - jack pine FRES11 Spruce - fir FRES15 Oak - hickory FRES18 Maple - beech - birch FRES19 Aspen - birch FRES23 Fir - spruce FRES24 Hemlock - Sitka spruce FRES26 Lodgepole pine FRES44 Alpine STATES : CT DE ID IL IN IA ME MA MI MN MT NH NY OH PA VT VA WA WV WI AB BC LB MB NB NF NT ON PE PQ SK YT BLM PHYSIOGRAPHIC REGIONS : NO-ENTRY KUCHLER PLANT ASSOCIATIONS : K002 Cedar - hemlock - Douglas-fir K015 Western spruce - fir forest K093 Great Lakes spruce - fir forest K094 Conifer bog K095 Great Lakes pine forest K096 Northeastern spruce - fir forest K100 Oak - hickory forest K106 Northern hardwoods K107 Northern hardwoods - fir forest K108 Northern hardwoods - spruce forest K109 Transition between K104 and K106 SAF COVER TYPES : 1 Jack pine 5 Balsam fir 12 Black spruce 13 Black spruce - tamarack 14 Northern pin oak 15 Red pine 16 Aspen 18 Paper birch 19 Gray birch - red maple 21 Eastern white pine 22 White pine - hemlock 23 Eastern hemlock 30 Red spruce - yellow birch 32 Red spruce 33 Red spruce - balsam fir 35 Paper birch - red spruce - balsam fir 37 Northern white cedar 38 Tamarack 107 White spruce 201 White spruce 202 White spruce - paper birch 204 Black spruce 206 Engelmann spruce - subalpine fire 218 Lodgepole pine 227 Western hemlock - western redcedar 251 White spruce - aspen 253 Black spruce - white spruce 254 Black spruce - paper birch SRM (RANGELAND) COVER TYPES : NO-ENTRY HABITAT TYPES AND PLANT COMMUNITIES : West: In the West, velvetleaf blueberry grows in submontane to subalpine forests [43] dominated by lodgepole pine (Pinus contorta), spruce (Picea spp.), jack pine (Pinus banksiana), western hemlock (Tsuga heterophylla), or western redcedar (Thuja plicata) [90,97]. Velvetleaf blueberry is a particularly common understory dominant on drier sites in the sub-boreal spruce zone of British Columbia [93]. East: In the Great Lakes region, velvetleaf blueberry commonly grows in xero-mesophytic pine woodlands [90] and bracken fern (Pteridium aquilinum)-grasslands [16]. Stands may be dominated by jack pine, black spruce (Picea mariana), eastern white pine (Pinus strobus), red pine (P. resinosa), quaking aspen (Populus tremuloides), birch (Betula spp.), a mixture of maple (Acer spp.)-aspen-birch (Betula spp.), eastern hemlock (Tsuga canadensis), or tamarack (Larix laricina) [13,38,64,90]. In the Maritime Provinces and northeastern United States, it grows in forests made up of black spruce (Picea mariana), white spruce (P. glauca), red spruce (P. rubens), and balsam fir (Abies balsamea) [23,90]. Further south in Pennsylvania and the southern Appalachians, it grows in oak (Quercus spp.)-hickory (Carya spp.) forests [75]. Velvetleaf blueberry grows abundantly with low sweet blueberry in managed commercial blueberry stands in New England and the Maritimes [33,59]. It is particularly common in recently cleared woodlots [5,30] and is a common oldfield colonizer on farms which were abandoned during the early part of the twentieth century [88]. Plant associates: In eastern forests, low sweet blueberry, bunchberry (Cornus canadensis), bog birch (Betula glandulosa), kalmia (Kalmia angustifolia), cloudberry (Rubus chamaemorus), bog Labrador tea (Ledum glandulosum), creeping wintergreen (Gaultheria hispidula), wild sarsaparilla (Aralia nudicaulis), red maple (Acer rubrum), bracken fern, and Canada beadruby (Maianthemum canadense) are common associates [23,28,68,85,90]. In the Great Lakes region and Upper Midwest, bracken fern, low sweet blueberry, bunchberry, twinflower (Linnaea borealis), bog Labrador tea, Canada beadruby, Cladonia spp. and various mosses often occur with velvetleaf blueberry [14,39,90]. In western North America, velvetleaf blueberry often grows with species such as kinnikinnick (Arctostaphylos uva-ursi), dwarf huckleberry (Vaccinium caespitosum), bunchberry, and Cladonia gracilis [90,93]. Published classifications listing velvetleaf blueberry an indicator of community types or habitat types are presented below. Jack pine - lichen woodland on sandy soils in northern Saskatchewan and northern Alberta [11] Field guide habitat classification system: For Upper Peninsula of Michigan and northeast Wisconsin [13] Forest community types of west-central Alberta in relation to selected environmental factors [14] Application of a forest habitat-type classification system in Michigan and Wisconsin [45] Field guide to forest habitat types of northern Wisconsin [46] Habitat classification system for northern Wisconsin [47] The Pinus contorta forests of Banff and Jasper National Parks: a study in comparitive synecology and syntaxonomy [51]


SPECIES: Vaccinium myrtilloides
IMPORTANCE TO LIVESTOCK AND WILDLIFE : Browse: White-tailed deer and eastern cottontail browse the leaves and twigs of velvetleaf blueberry [90]. In many parts of the East, deer browse shoots or twigs during the fall and winter months [5,75]. Domestic sheep however, generally ignore velvetleaf blueberry [90]. Fruit: The wild turkey, gray catbird, band-tailed pigeon, ring-necked pheasant, and quails, ptarmigans, towhees, spruce, ruffed, blue, and sharp-tailed grouse all feed on Vaccinium fruit [54,88,91]. In central Pennsylvania, grouse eat large numbers of velvetleaf blueberry flower buds in winter [75]. The American robin, American crow, bluebirds, and many other small birds consume velvetleaf blueberry fruit [5,76,90]. The white-tailed deer, black bear, red fox, porcupine, raccoon, mice, and chipmunks all readily feed on the fruit of velvetleaf blueberry [76,90]. Mammals such as the pika, white-footed mouse, gray fox, ground squirrels, deer mice, squirrels, and skunks eat large quantities of Vaccinium berries [54,91]. In parts of Minnesota and Wisconsin, the reproductive success of black bears is reduced in years of Vaccinium crop failure [70]. PALATABILITY : Velvetleaf blueberry fruit is highly palatable to a wide variety of birds and mammals. Specific palatability of berries varies with the clone [90]. Browse appears to be of relatively low palatability to most big game species and to domestic livestock. NUTRITIONAL VALUE : Browse: Blueberry (Vaccinium spp.) foliage is relatively high in carotene, manganese, and energy content [18,35,90]. Nitrogen content of velvetleaf blueberry generally declines through the growing season whereas calcium and magnesium levels increase [90]. Plants accumulate nitrogen for winter, but apparently do not store reserves of protein [50]. Nutrient content of mature velvetleaf blueberry foliage is as follows [90]: element percent dry weight element micrograms/gram N 1.5-2.00 Fe 20-192 P 0.09-0.21 Mn 202-2,177 K 0.24-0.52 B 16-54 Ca 0.38-0.67 Mg 0.10-0.31 Fruit: Blueberry fruits are sweet and contain high concentrations of both mono- and di-saccharides [82]. Berries are rich in vitamin C, carbohydrates, and energy content but low in fats [69,92]. The nutrient value of Vaccinium berries from Pennsylvania is documented below [92]. crude ether crude total N-free avail. lignin protein extract fiber ash extract protein %dry wt. 4.19 3.80 9.67 1.44 80.90 2.75 13.85 % of fruit .63 .56 1.42 .21 11.88 .50 2.04 cellulose tannin Ca Mg P moisture %dry wt. 7.97 1.28 0.4 .07 .07 - % of fruit 1.17 .19 .01 .01 .01 85.3 Flowers: Nectar of velvetleaf blueberry flowers contains more sucrose than do the flowers of low sweet blueberry [94]. COVER VALUE : NO-ENTRY VALUE FOR REHABILITATION OF DISTURBED SITES : Species within the Vaccinium genus can be propagated from hardwood cuttings or by seed. Blueberry (Vaccinium spp.) seedlings grown in the greenhouse can be transplanted onto favorable sites 6 to 7 weeks after emergence. Germination of velvetleaf blueberry is generally best in 1:1 sand-peat mixtures at a pH of 4.5 [90]. Seed collection and storage techniques have been considered in detail [15]. OTHER USES AND VALUES : The sweet, tart or "pleasantly acid" [76,86] fruit of velvetleaf blueberry is eaten fresh or used in pies, pastries, jam, and ice cream [5]. Large numbers of recreationists seek out and harvest these berries throughout the Great Lakes Region [42,90]. During the 1970's, approximately 20 percent of the total visitor hours were dedicated to blueberry picking in several National Forests of northern Minnesota. By 1980, this amount had climbed to 30 percent in some locations [42]. Vaccinium berries were traditionally an important food source for many native American peoples [76]. The Cree harvested velvetleaf blueberries in parts of western North America [88]. Velvetleaf blueberry grows with low sweet blueberry in commercial blueberry fields of the Northeast [1,59]. In some areas, velvetleaf blueberry may represent a significant part of the commercial crop, particularly in fields derived from woodlands [33,88]. However, it only accounts for "commercially viable" quantities in New Brunswick and Maine. More than 4,400,000 pounds (2 million kg) of blueberry fruit is harvested annually in New Brunswick, of which 30 percent is velvetleaf blueberry. Most commercially grown fruit is processed as pie filling or is used in muffin mixes [90]. Lesser amounts are used to make wine, juice, or freeze-dried products [5]. The cold-hardy velvetleaf blueberry may have potential for breeding blueberry strains suited to northern climates [19]. Its affinity for mineral soil also suggests that it may be useful for breeding plants adapted to upland sites [22,44]. OTHER MANAGEMENT CONSIDERATIONS : Chemical control: Blueberries (Vaccinium spp.) exhibit variable susceptibility to herbicides such as 2,4-D, 2,4,5-T, glyphosate, karbutilate, and picloram [8]. Various herbicides, including dichlorprop, picloram, 2,4-D, and glyphosate have been applied to velvetleaf blueberry to facilitate conifer release [26,72]. Plants are resistant to Asulam and Terbacil, although Dicamba and 2,4-D may reduce shoot numbers during the year after treatment. However, rhizomes may be undamaged by herbicides and often resume growth during the second year after treatment [90]. The response of velvetleaf blueberry to various herbicides has been documented [72,90]. Mechanical treatment: In northeastern Minnesota, mechanically clipped velvetleaf blueberry plants produced flower bud numbers equal to those on unpruned plants. Plants pruned mechanically, or by fire, exhibited increases in stem numbers over unpruned controls. The effects of fertilizer and mulch on pruned plants has been examined in detail. Application of fertilizer may significantly increase flower bud numbers on clipped individuals but typically reduces flower bud development on unpruned plants. Unpruned plants generally exhibit increased stem growth after fertilizer application, but fertilization has little effect on mechanically pruned plants [76]. Mulch does not generally increase flower bud numbers or vegetative growth of pruned plants. Its use should be avoided on recently pruned velvetleaf blueberry [76]. Environmental considerations: In a number of recent studies, chemically treated velvetleaf blueberry plants have been found to produce fruit which exceeds permissible levels of herbicides [26,72]. In a northeastern Ontario study, 50 percent of fruit tested was found to exceed FDA safety standards. Much of the affected fruit grew in easily accessible areas, such as along highway right-of-ways. Possible human health risks are unknown, but approximately 0.3 percent of all wild blueberries and red raspberries (Rubus idaeus) in Ontario are treated annually with herbicides [26]. In many parts of the East, widespread use of insecticides has decimated populations of wild bees which formerly pollinated blueberry fields. In some locations, it is now necessary to supplement natural pollinators with honey bees to ensure adequate fruit set in commercially managed fields [58]. Velvetleaf blueberry is very sensitive to sulfur dioxide pollution and may be a useful indicator for monitoring acid rain [90]. Commercial propagation: Numerous cultivation techniques have been applied to commercially managed blueberry fields [76,98]. These include applying mulch, fertilizer, or herbicides, and pruning with fire or mechanical means [see FIRE MANAGEMENT CONSIDERATIONS]. Various herbicides can be used to control plants such as kalmia (Kalmia angustifolia) and little bluestem (Schizachyrium scoparium) which commonly compete with velvetleaf blueberry in commercially managed berry fields [30,95]. Disease and insects can greatly reduce fruit yields under certain circumstances. Because clones differ genetically in their resistance to disease, selective breeding has been used to develop resistant strains [59]. In commercial blueberry fields containing both velvetleaf and low sweet blueberry, yields are often lower than in fields made up of only low sweet blueberry. Cross pollination apparently results in reduced fruit set [1]. Berry production: Fruit production in velvetleaf blueberry fluctuates annually according to the genetics of the individual clone, weather conditions, and insect availability [5,94]. However, fruit production is often good [16] and nearly all berries contain some viable seed [90]. Pollinators are required for good fruit set [94] and dry, warm weather during flowering generally results in more active insect pollinators and better fruit set. Late spring frosts can greatly reduce fruit production [90]. In Newfoundland, reduced fruit production has been correlated with heavy June precipitation and in Nova Scotia, warm temperatures and ample sunlight enhanced fruit yields [31]. Fruit production of velvetleaf blueberry typically declines as clones age [75]. Production often peaks 10 to 20 years after fire, just prior to canopy closure [90]. Damage: Plants may be damaged by cold winter temperatures. Shrubs are often killed to ground level in the absence of a protective snow cover. Spring frost damage reportedly occurs at 30 degrees F (-1 degree C) and may be "complete" at 14 degrees F (-10 degrees C) [90]. Livestock: Ericaceous shrubs such as velvetleaf blueberry tend to increase in response to heavy livestock grazing [28]. Wildlife considerations: Blueberries are an extremely important food source for bears. In many areas, bear-human conflicts are most likely to occur during years of Vaccinium berry crop failure [55,70]. Both black and grizzly bears typically exploit areas with dense concentrations of berries. The habitat value of blueberry shrubfields to grizzly bears can be increased by permanent, or at least seasonal road closures, by coordinating timber harvest dates to have minimal impact on habitat use patterns, and by considering the cumulative effects of habitat modification across a broad area. In general, site preparation should include minimizing soil compaction, using cooler broadcast burns rather than hot burns, or by eliminating site preparation entirely wherever possible. Grizzly use is favored where hiding cover is retained by treating small, irregular patches instead of large contiguous areas, and by leaving stringers of timber within larger cuts [96].


SPECIES: Vaccinium myrtilloides
GENERAL BOTANICAL CHARACTERISTICS : Velvetleaf blueberry is a dwarf, deciduous shrub which grows from 4 to 35 inches (10-89 cm) in height [10,78,86,90]. This rhizomatous shrub commonly forms small open colonies [88]. However, on favorable sites, a single plant may reach 33 feet (10 m) in diameter [90]. Velvetleaf blueberry typically develops an extensive network of roots and woody rhizomes [76,90]. The numerous shallow roots are fibrous and much-branched, with considerable lateral spread [5,77]. Roots average 0.004 to 0.02 inch (0.1-0.5 mm) in diameter [5]. Taproots may be absent [77], although at some sites, taproots averaging 0.4 inch (10 mm) in diameter have been reported at depths to 3 feet (91 cm) [29,53]. Elsewhere, researchers have observed maximum rooting depths of 4 to 6 inches (10-15 cm) [84]. Clonal variation in the number of shoots and rhizomes, and in rhizome depth has been reported [77]. Branches are velvety pilose [76] and ascending [90]. Twigs are green or brown [88] and the bark, a "dirty brown" or green [90]. Stem morphology has been examined in detail [60]. The thin, alternate, entire leaves are elliptic to sublanceolate and 0.8 to 1.6 inches (2-4 cm) in length [10,78,90]. The leaf base is obtuse or cuneate and the apex acute [78,86]. The upper leaf surface is bright green whereas the undersurface is paler [86]. Leaves are variable [86] but, as the name velvetleaf blueberry suggests, are usually pubescent on both sides [88]. White to greenish, pale pink or purple-tinged flowers [10,78,86] are borne in terminal or lateral racemes [90]. Flowers are drooping, urceolate, or broadly cylindric-campanulate in shape [68,86,90]. Floral morphology has been examined in detail [65]. Velvetleaf blueberry is cluster-fruited species [19]. Fruit is a bright, frosty blue to dark blue, or, less commonly, white (as in the form chicococcum) berry which averages 0.16 to 0.4 inch (4-10 mm) in diameter [78,86]. Berries are generally glaucous [88] and contain several small seeds or nutlets 0.04 inch (1.0 mm) in length [88,90]. Berries contain an average of 16 viable seeds; 100 seeds weigh approximately 26 mg [90]. RAUNKIAER LIFE FORM : Phanerophyte REGENERATION PROCESSES : Velvetleaf blueberry is capable of reproducing vegetatively or by seed. However, regeneration after fire and other types of disturbance is primarily vegetative [28]. Vegetative regeneration: Velvetleaf blueberry is characterized by an extensive network of woody rhizomes. Rhizomes are generally much-branched laterally, and give rise to many fibrous roots and shoots [77,90]. Rhizomes usually grow rapidly in several directions once plants reach 8 to 12 inches (20-30 cm) in diameter [90]. Depth, length, and annual radial growth rates appear to be highly variable [77]. Rhizomes average approximately 0.15 inch (4 mm) in diameter and extend 3 to 46 feet (1-14 m) in length [29,77]. Rhizomes typically occur from 1.8 to 3.5 inches (4.5-9.0 cm) below the soil surface [53], although depth depends on genetic factors and on site characteristics such as the thickness of organic soil. Normal rhizome depth is apparently inversely related to the thickness of organic soil. In eastern Canada, mean depth of underground regenerative tissue in velvetleaf blueberry is 3.1 inches (8 cm) [23,24]. In Alberta, shoots may occasionally develop from rhizomes as deep as 4.3 inches (11 cm) [77]. Approximately 73 percent of all shoots developed terminally on rhizomes, with 27.7 percent developing from the middle [77]. Smith [77] reported rhizome length and depth as follows in an Alberta study: sites 1 2 3 4 5 6 average length (cm) 143.7 325.7 422.3 625.8 735.5 653.1 average depth (cm) 6.8 8.5 7.1 6.9 4.5 9.0 avg. # of sprouts/100 cm of rhizome length 1.2 1.5 2.2 1.9 1.6 1.0 organic horizon 3 6 7 7 10 3 thickness (cm) slope (degrees) 40 10 3 2 3 20 aspect NE S NE E NE S tree cover (%) 81-100 41-60 81-100 81-100 21-40 0-20 # trees > 1 in. 27 12 32 28 5 4 Velvetleaf blueberry also sprouts from the bole, stump, or stem base when disturbances such as fire destroy only portions of the aboveground foliage [5,11,88]. Seed: Velvetleaf blueberry begins fruiting during the third growing season [90]. It is generally considered to be self-sterile and requires insect pollination for fruit set [1,58,90]. Bees are the most common insect pollinators, with bumblebees the most effective [58,68]. Seeds of velvetleaf blueberry can germinate on mineral or organic soils when moisture and aeration are adequate [90]. Germination: Germination of velvetleaf blueberry has been described as sporadic [87]. Germination rates have ranged from 20 to 30 percent in carefully controlled laboratory experiments. Seeds typically germinate from 18 to 82 days after planting; germination tends to be bimodal with large numbers of seeds germinating early and late [90]. Seeds of most blueberries (Vaccinium spp.) are not dormant and require no pretreatment for germination [15]. Radicles first develop approximately 20 days after seeds are sown, cotyledons emerge within 31 days, and the first leaves unfold in 48 days [90]. Seed dispersal: Seeds of velvetleaf blueberry are readily dispersed by various birds and mammals [58]. Evidence suggests that long-distance seed dispersal by many birds and mammals can effectively increase genetic diversity in the velvetleaf blueberry. The American robin is a particularly effective dispersal agent. Fruit typically ripens just as birds are preparing for seasonal migrations [90]. Vander Kloet and Hall [90] report that viability is reduced by 10 percent after seed passes through the digestive tracts of birds and mammals. However, Krefting and Roe [48] suggest that digestive processes may actually enhance germination. Seeds obtained from black bear scats apparently germinate more readily than do those from uneaten fruit [71]. Composite samples of velvetleaf and low sweet blueberry (50:50) were as follows [71]: percent germination uneaten fruit seed from feces unrefrigerated 9 15 refrigerated 16 20 Seedling establishment: Initial growth is typically slow wherever significant competition is present such as in oldfield communities [90]. Plants may require 5 years to reach 6 inches (15 cm) in diameter [. SITE CHARACTERISTICS : Velvetleaf blueberry is common in drier, relatively infertile conifer types [90]. Velvetleaf blueberry also grows in forested portions of bogs, in muskegs, peatlands, treeless mountain slopes, alpine meadows, mountain meadows, barrens, headlands, boreal forests, and on rock outcrops [10,68,88]. It commonly reaches greatest abundance on disturbed sites such as in clearcuts or on recent burns [88,90]. Light regimes: Evidence suggests that conditions necessary for the growth of velvetleaf blueberry differ in eastern and western North America. On foggy, low elevation sites in New Brunswick, shade appears to have a detrimental effect on the growth and development of velvetleaf blueberry [77]. However, on dry, intensely sunny sites in Alberta, shade enhances growth by aiding in water conservation [77]. Velvetleaf blueberry is generally tolerant of shade and grows well in open woods [30,33]. Hoefs and Shay [37] note that it prefers low light intensity although some researchers report that berry production is enhanced in sunny locations [86]. Climate: Velvetleaf blueberry grows across a wide range of climatic conditions [90]. It grows in perhumid climates on the East Coast and in dry subhumid or cool, temperate climates in the West [43,90]. In the West, its abundance increases with greater continentality [43]. Growing season length ranges from 60 to 200 days [53,90]. Soils: Most blueberries (Vaccinium spp.) require acidic soils and can grow on infertile sites which have relatively small amounts of many essential elements [44]. Velvetleaf blueberry grows on a wide variety of soil types including well-drained coarse, or light-textured soils. It occurs on fine sandy soils, loam, clay loam, till, and lacustrine deposits [14,39,53]. Velvetleaf blueberry generally reaches greatest abundance on moderate to light, often sandy, well-drained soils with adequate soil moisture [77,90]. Soils are generally acidic, with pH ranging from 3.0 to 5.9 [34,40]. Soils are commonly nitrogen-poor [43,50] but may be rich in organic matter [34,43]. Organic content ranges from 3 to 93 percent [90]. Elevation: Velvetleaf blueberry grows from sea level to 3,950 feet (0-1,200 m) [90]. Generalized range by geographic location is as follows [20,86]: from 3,200 to 4,300 feet (975-1,311 m) in MT > 2,950 feet (900 m) in VA SUCCESSIONAL STATUS : Velvetleaf blueberry commonly reaches greatest abundance in young postdisturbance communities [90]. In the East, velvetleaf blueberry vigorously colonizes disturbed sites such as clearcuts, recently burned pine forests, and oldfields [78,88,90]. Throughout New England and the Maritime Provinces, it colonized old farms which were abandoned in the early part of the twentieth century [88]. Velvetleaf blueberry often forms dense stands during seral stages after clearcutting in balsam fir-red spruce forests [90]. Residual velvetleaf blueberry plants commonly colonize burned sites in northern boreal forests [78] and elsewhere. Reestablishment is often rapid, particularly after light to moderate fires [see Plant Response to Fire]. Velvetleaf blueberry can assume prominence within 2 to 3 years after fire in jack pine woodlands [83]. In parts of parts of British Columbia, velvetleaf blueberry commonly assumes dominance soon after fire on dry to intermediately moist sites but is typically absent from wet sites [36]. After hot fires in northern Ontario, velvetleaf blueberry was initially replaced by more fire-tolerant species such as Fremont sedge (Carex aenea), poverty oatgrass (Danthonia spicata), and sweet fern (Comptonia peregrina) [71]. An extended period of moss and grass dominance may occur prior to velvetleaf blueberry reestabishment on severely burned sites [78]. In parts of eastern Canada, a wintergreen (Gaultheria procumbens)-Canada beadruby-velvetleaf blueberry-bunchberry association commonly develops under a regime of frequent, light fires. However, a bunchberry-velvetleaf blueberry-kalmia-bracken fern association is more typical where fire intervals are longer and fires more severe [23]. In northern Quebec, low sweet blueberry may gradually replace velvetleaf blueberry on burned areas as velvetleaf blueberry becomes restricted to shady sites [53]. Velvetleaf blueberry can persist in a variety of mature or climax forest stands. Limited evidence suggests that it is more tolerant of shade than other sympatric species of Vacciniums. It can survive in closed stands, including white spruce-balsam fir forests, but flowering is generally limited to forest openings [90]. Flowering and fruiting is typically much reduced or absent in dense shade in all community types [99]. SEASONAL DEVELOPMENT : Phenological development of velvetleaf blueberry varies according to weather conditions, geographic location, and the genetic complement of the individual clone [5,90]. In eastern Ontario, vegetative buds begin to swell in late April or early May, as night time temperature exceeds 42 degrees F (6 degrees C) for 4 or 5 days at a time. Leaves harden by mid-June and turn red in early October or as early as July or August in drought years [90]. Leaves generally abscise by late October. Elongation of vegetative shoots ceases in June [5], and plants overwinter without leaves. Phenological development in northeastern Ontario has been documented as follows [78]: phenological stage mean # of days - budbreak in spring 23 - # of days from loss of bud scales and swelling of flowerbuds until 50% of flowers open 28 - # of days between vegetative budbreak and death of apical meristem 28 - # of days between vegetative budbreak and maturation of lateral buds 60 Flowering occurs the spring, either before or during shoot development. Flower primordia form in late summer after annual vegetative growth is complete [5,90]. Flower buds begin to swell in late April or May [90]. Berries generally ripen 49 to 68 days after flowering [90]. Ripening time is greatly influenced by precipitation, temperature, and various site characteristics. Annual variation in ripening is documented in the following Ontario study [26]: percent ripe 1979 August 22 80 August 30 100 September 5 overripe percent ripe 1980 August 6 60 August 20, 25 100 September 2, 15 100 September 22 overripe percent ripe 1981 August 12 20 20 -- August 17-19 40 40 45 August 24-25 50 50 60 September 1-2 70 70 85 September 9-10 90 85 100 September 14-15 100 100 -- Generalized seasonal development by geographic location is as follows [5,74,78,86]: location flowering fruiting New England May 15-June 22 ---- c NY mid May ---- e ON mid to late May ---- ME, NB, NS, ne PQ, LB n ON, n MB, SK, nAB, NT late May to early June ---- BC late May to late June ---- VA May-June July-August s ME ---- late June ON ---- July-September


SPECIES: Vaccinium myrtilloides
FIRE ECOLOGY OR ADAPTATIONS : Velvetleaf blueberry commonly sprouts from the stem base or rhizomes after aboveground foliage is removed or damaged by fire [11,90]. Some seed may be transported to burned sites by birds and mammals. Velvetleaf blueberry appears to be well adapted to a regime of fairly frequent fires. Although berry production may be much-reduced, velvetleaf blueberry is apparently able to persist for years beneath a closed canopy forest. Old clones decline in vigor, but periodic fires initiate vigorous sprouting and regrowth. In the East, native Americans and early European settlers used fire in wild berry fields containing velvetleaf blueberry to enhance fruit production [76]. Evidence suggests, however, that velvetleaf blueberry is less tolerant of annual or biennial fires than its conspecific, low sweet blueberry [78]. Fire is a particularly common influence in northern boreal forests where velvetleaf blueberry grows as an understory dominant or codominant [23]. Fire intervals in these areas vary, but often range from 27 to 54 years. In parts of northern Minnesota, fire intervals have been estimated at 30 years [76], and in the jack pine woodlands of Alberta's Athabasca Plains, patchy burns occur every 28 to 54 years [11]. Peak abundance of velvetleaf blueberry evidently corresponds to these intervals. Peak frequencies have been observed approximately 27 years after fire in parts of Minnesota [73]. In parts of northern Ontario, increases in velvetleaf blueberry have been observed approximately 50 years after fire [78]. Fire intervals in many coniferous forests of eastern Canada are somewhat longer than in boreal forests to the north. Flinn [23] reported average fire intervals of approximately 370 years. FIRE REGIMES : Find fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find Fire Regimes". POSTFIRE REGENERATION STRATEGY : survivor species; on-site surviving root crown or caudex survivor species; on-site surviving rhizomes off-site colonizer; seed carried by animals or water; postfire yr 1&2


SPECIES: Vaccinium myrtilloides
IMMEDIATE FIRE EFFECT ON PLANT : Aboveground portions of velvetleaf blueberry are commonly killed by fire, but underground rhizomes generally survive wildfires or controlled burns [24,88,90]. Mortality typically increases with higher fire intensity and severity [56,78], although in the West, some rhizomes commonly survive even hot wildfires, as long as soil is sufficiently deep to offer some protection [90]. Some plants may survive even after lethal heat penetration to depths of 3.5 to 4.7 inches (9-12 cm) [23]. Rhizomes are typically most susceptible to heat damage during the period of active growth [78]. Seed: Seeds of most Vacciniums are of short viability and are readily killed by heat [55]. DISCUSSION AND QUALIFICATION OF FIRE EFFECT : NO-ENTRY PLANT RESPONSE TO FIRE : Vegetative response: Velvetleaf blueberry typically sprouts from underground rhizomes after aboveground portions of the plant are consumed by fire [29,90]. Sprouting from latent buds located on the stump or bole can occur where damage to the aboveground portions of the plant is only partial [11,28,90]. Response depends on a number of factors including season of burn, fire intensity and severity [24,78,90], and subsequent weather conditions. Seedling establishment: Seed banking does not appear to represent an important regenerative strategy in the velvetleaf blueberry. However, birds and mammals may transport some seed to burned sites. Season of burn: Response of velvetleaf blueberry is generally best after spring or fall burns [23,90]. Rapid regeneration or regrowth has been noted after spring fires in northeastern Minnesota and in red spruce-black spruce forests of eastern Canada [61,85]. Generally, poorest response occurs after plants are burned in summer during periods of most active growth [79]. Fires during dormant periods remove old shoot growth and provide additional nutrients which result in greater cover and enhanced productivity [78]. Good regrowth was noted after fall burns in eastern Canada which occurred after storage of photosynthate. Stored nutrients were presumably available for new growth in spring after the burn [25]. In eastern Canada, plants burned in mid-August exhibited reduced berry production by the end of the second growing season. Plants burned in late August showed no increase in berry production but did increase in cover [78]. Late October burns produced increases in both fruit production and cover whereas, burns conducted in late May reduced cover and did not increase berry production [78]. Fire intensity and severity: Light to moderate fires presumably remove decadent material and stimulate the growth of velvetleaf blueberry while increasing nutrient availability [79]. Plants are commonly observed on lightly burned plots in white spruce-paper birch-aspen communities [4] and elsewhere [78]. However, cover and fruit production may be greatly reduced after hot fires which result in greater heat penetration into the soil [55,78,79]. In a northern Ontario study, largest increases in cover and fruit production were noted after fires of 684 degrees F (362 degrees C) and 751 degrees F (417 degrees C) lasting 40 seconds per meter square [78]. Fruit production was much reduced after hot fires of 1,296 to 1,513 degrees F (702-823 degrees C) with a duration of 80 seconds per meter square [78]. Recovery may be slow after hot fires [61]. Ohmann and others [61] report that velvetleaf blueberry was more common in mature forests than in areas burned by a severe wildfire 33 years earlier. Soil: Soil characteristics may also influence the postfire response of velvetleaf blueberry. Reductions in cover and production may be more pronounced when the soil is dry [78]. The extent of lateral rhizome development may be greatest where organic soil layers are relatively thick [77]. Thus, the capacity to regenerate through rhizomes could be reduced where a thin mantle of organic soil prevents the development of an extensive rhizome network. Postfire recovery: Recovery of velvetleaf blueberry is generally rapid wherever portions of underground rhizomes survive [55,78]. This shrub regained prominence within 2 to 3 years after fire in jack pine communities of the East [83]. Relatively rapid increases in both cover and biomass have also been documented [62,63]. Rapid increases in biomass are often particularly dramatic during the first 2 years after fire [63]. DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : Season of burn: Response of velvetleaf blueberry is generally better after early spring or fall burns than after late spring or summer burns. Response by season of burn was documented as follows in forests of eastern Canada [25]: season of burn relative abundance (stem density for velvetleaf blueberry in plot/stem dens. for all species in plot) x 100 preburn 1 month 3 months 5 months late spring (early July) --- --- --- 17 % summer (July 20-22) --- --- --- 25 % fall (September 15-17) --- --- 37% 30 % Postfire recovery: Reestablishment of velvetleaf blueberry is often fairly rapid where surviving portions of the plant sprout. Postfire increases in cover and biomass were as follows in northeastern Minnesota [62,63]: year postfire percent cover (avg. of 7 sites) 1 0.6 2 0.2 3 1.1 4 0.7 5 1.1 postfire growing individual dry number of season weight (gms) individuals 1971 .16 140 1972 .75 29 1973 .70 64 1974 1.43 84 1975 1.60 151 In northern Minnesota, comparative values from burned and unburned three year old stands were as follows [76]: unburned burned stems/0.1 m sq. 2.3 2 flower buds/plant 6 8 stem length (cm) 22 24 The Research Project Summary Understory recovery after burning and reburning quaking aspen stands in central Alberta provides information on prescribed fire and postfire response of plant community species, including velvetleaf blueberry, that was not available when this species review was originally written. FIRE MANAGEMENT CONSIDERATIONS : Wildlife: Evidence suggests that fire suppression may be having an adverse impact on bear habitat in some areas [55,96]. Once-productive berry fields are being invaded by conifers. Since plants beneath a forest canopy generally produce few berries, fruit production has been steadily declining in many areas [57]. Berry fields can be treated with fire if maintenance or enhancement of berry crops is a prime management objective. Logging treatments which include severe soil scarification or slash burns may also reduce berry production. Even where timber harvest favors berry production, lack of cover in early years can limit bear use. Wildfires often create diverse habitat mosaics which incorporate elements of hiding cover and favor bear use [96]. Prescribed fire: Prescribed fire has long been used to increase yields in commercial low sweet blueberry fields of the East by naturally pruning decadent shoots [23,42,57]. Flower buds generally tend to be more numerous on new shoots and periodic removal of old shoots can increase fruit yield as well as enhance overall vigor [57,75]. Prescribed fire has also proven effective in increasing fruit yield for wildlife and recreationists in noncommercial forest stands of the Upper Midwest [7]. In northern Minnesota, fruit production of blueberries (Vaccinium spp.) was enhanced by the second growing season after fire [7]. In addition to increased numbers of berries, fruit size was noticeably larger than on adjacent unburned plots [7]. Spring burns, conducted when the soil is still moist, tend to be effective in promoting fruit production. In the Great Lakes Region, Kautz [42] recommends burning blueberry (Vaccinium spp.) stands with 4 to 5 years fuel accumulation during the early afternoon on warm, clear, sunny days with average wind speeds of 5 to 10 miles per hour (6-8 km/hour). Fast-moving fire fronts, which burn aboveground parts but leave underground regenerative structures intact, generally produce best results. Therefore, when increased blueberry fruit production is a primary management objective, head fires are preferable to backing fires. It may be necessary to add fuels when burning blueberry stands in the East. In the Great Lakes Region, areas to be burned should be rotated over a 4- to 5- year interval to maintain adequate berry production for recreationists and wildlife [42]. In the Great Lakes region, blueberry stands are typically burned at 4 to 5 year intervals rather than at the 1 to 2 year intervals common in the Northeast [76]. Many commercial stands made up of both low sweet blueberry and velvetleaf blueberry, have been burned at two year intervals [88]. While burning at this interval is beneficial to low sweet blueberry, velvetleaf blueberry generally decreases [30,88,90]. However, burning at three year intervals appears to benefit woodlots made up of both species [28]. Commercial berry fields are commonly burned in spring or fall [5,76,78]. Moderate burns conducted during dormant periods are generally most effective [78]. Flame throwers may be used [56] and hay or straw spread at the rate of 1 ton per acre. Damage to underground portions of the plant can be minimized by burning when the ground is still frozen [5]. Timber harvest: Thinning by pulpwood cutting commonly produces vigorous velvetleaf blueberry plants. However, clearcutting when followed by burning within one year often causes shrubs to decline. Clearcutting exposes small plants, often of poor vigor, to direct sunlight. Presumably, when already weakened shrubs are burned, mortality can occur. If plants are allowed to grow for several years after clearcutting and attain good vigor, most generally survive subsequent fires. Velvetleaf blueberry typically responds better if the tree canopy is opened gradually, or if narrow strips are cut allowing vigorous rhizome expansion from adjacent undisturbed areas. After timber harvest in the fall of 1949 and an April 1951 burn in New Brunswick, velvetleaf blueberry responded as follows [28]: 1949 1950 1951 1952 (plots sampled in June) # of stems 45 44 71 77 frequency 8 9 7 2 percent cover 1.6 0.2 0.5 0.1 Biomass production of velvetleaf blueberry one year after timber harvest and fire was as follows in northeastern Minnesota [63]: dry g/m sq. unlogged-unburned 0.12 logged-unburned 1.53 head fire-logged-burned -- back fire-logged-burned 0.09 Application of fertilizer and mulch: The effects of mulch and fertilizer application on burned velvetleaf blueberry stands has been examined in detail. Study results indicate that plants on burned sites respond more favorably if fertilizer applications are delayed for one year to allow plants additional time for regrowth [76].


SPECIES: Vaccinium myrtilloides
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