© 2006 Robert Svensson.
Polytrichum juniperinum Hedw. var. affine (Funck) Brid., P. juniperinum var. alpestre (Hopp) Brid., and P. juniperinum Hedw. var. gracilius Wahlenb. are now classified as upright haircap moss (P. strictum) Brid. , so information on those taxa is not included in this review.SYNONYMS:
Northern communities: Across North America, juniper haircap moss is reported most often in early-successional boreal and subboreal spruce (Picea spp.) taiga communities of Alaska and northern Canada (for example, [35,53,65,119,148]). In northern Quebec, juniper haircap moss, common haircap moss (P. commune), and globose haircap moss (P. piliferum) dominated the floor of a black spruce-jack pine (Picea mariana-Pinus banksiana) forest that had established after a wildfire 47 years previously . The moss layer in boreal and subboreal communities is often diverse; a moss species with 1% to 2% cover or frequency can be common to dominant on some sites [50,57,109,117,122,134].
Juniper haircap moss frequently occurs in northern shrublands. It is an important component of dwarf birch (Betula nana), willow (Salix spp.), and heath tundra communities in Alaska and western Canada . In central Alberta, juniper haircap moss was an associated species on a bog Labrador tea/red sphagnum (Sphagnum rubellum) peatland .
Northeastern communities: Juniper haircap moss is often noted as a component of northeastern coniferous forests. In a study in southeastern Manitoba, juniper haircap moss occurred in a tamarack/bog birch-sedge-yellow marsh marigold-purple marshlocks (Larix laricina/Betula glandulosa-Carex spp.-Caltha palustris-Comarum palustre) forest . Juniper haircap moss is a common to dominant moss in fire-maintained pitch pine (Pinus rigida) barrens [44,86,100,131]. In the Adirondack Mountains of New York, juniper haircap moss was the most common moss on study plots in the pitch pine barrens . In New Jersey, juniper haircap moss and reindeer lichens (Cladonia (Cladina) spp.) formed mats in fire-maintained canopy openings within pitch pine barrens . Juniper haircap moss is an indicator species of unproductive conditions for Virginia pine (Pinus virginiana) stands in central Pennsylvania. Sites with "an unusual abundance" of juniper haircap moss are generally "poor" sites with open canopies on dry, high-elevation ridges .
Juniper haircap moss is occasionally reported in forests that rarely experience disturbance. For example, it grows in old-growth Atlantic white-cedar-red maple (Chamaecyparis thyoides-Acer rubrum) swamps in New Jersey .
Juniper haircap moss and common haircap moss were components of a catberry-highbush blueberry (Nemopanthus mucronata-Vaccinium corymbosum) heathland in central New York .
Western communities: In western North America, juniper haircap moss occurs in coniferous forest, grassland, alpine, and herbaceous subalpine communities. In British Columbia it occurs in subalpine fir-Engelmann spruce (Abies lasiocarpa-Picea engelmannii) forests . Juniper haircap moss is "occasional to frequent" in white spruce (P. glauca) stands of central Alberta . Juniper haircap moss occurs in the coast Douglas-fir (Pseudotsuga menziesii var. menziesii)- mountain grassland transition zone in western Washington  and in Rocky Mountain Douglas-fir/mountain big sagebrush (P. m. var. glauca/Artemisia tridentata subsp. vaseyana) communities of Hell's Canyon National Recreation Area and Medicine Lodge Peak, Idaho .
Juniper haircap moss may form cryptogamic soil cover on palouse prairies and mountain grasslands. Tveten and Fonda  found juniper haircap moss was a dominant moss on the Wier Prairie of Fort Lewis, Washington; juniper haircap moss and hairy rhacomitrium moss (Rhacomitrium canescens) had approximately 23% cover. Idaho fescue (Festuca idahoensis) dominated the palouse prairie site; 3- to 5-year-rotation prescribed fires and livestock exclusion are used to maintain historical palouse prairie vegetation . Juniper haircap moss formed part of the cryptogamic soil crust in a bluebunch wheatgrass (Pseudoroegneria spicata)-Idaho fescue community of Hell's Canyon National Recreation Area, Oregon .
Juniper haircap moss occurs in alpine and subalpine herbaceous as well as coniferous forest communities in the Cascade Range. In British Columbia and Washington, juniper haircap moss was noted in woolly pussytoes (Antennaria lanata) alpine fellfield, sedge (Carex spp. and Kobresia myosuroides) meadow, timber oatgrass (Danthonia intermedia) meadow, heath, and willow (Salix nivalis and S. cascadensis) communities. It was most important in capitate sedge (C. capitata) meadows . Juniper haircap moss was a component of an alpine fellfield community on Monument Peak in Oregon. Common woolly sunflower (Eriophyllum lanatum) and woolly rhacomitrium moss (Rhacomitrium languinosum) dominated the community .
Juniper haircap moss was the most abundant species on subalpine sites in Wyoming where snowfields remained through mid-July. The authors suggested that on sites covered with snow for most of the year, the short growing season limits establishment of vascular species. Rocky Mountain lodgepole pine (Pinus contorta var. latifolia) and subalpine fir-Engelmann spruce forests surround the snowfields .
Juniper haircap moss is occasional in cold western hardwood communities such as aspen (Populus spp.). In central Alberta, juniper haircap moss was more frequent in balsam poplar (Populus balsamifera ssp. balsamifera) stands (14%) than in balsam poplar-quaking aspen (P. tremuloides) (8%) and quaking aspen (3%) stands .
Juniper haircap moss is often associated with fireweed (Chamerion angustifolium) across broad geographic areas [42,65,118,135,145]. Juniper haircap moss also associates with other haircap mosses [42,57,68,78,130,135], fire moss , reindeer lichens (Cladonia spp.) [50,130], and the liverwort Marchantia polymorpha [130,151] on many sites across juniper haircap moss's distributional range. Common hair cap moss generally grows taller than juniper haircap moss and may successionally replace juniper haircap moss on mesic sites [42,57,68,68]. See Successional Status and Northern ecosystems for further information on the ecology of these associations.
Vegetation typings describing plant communities where juniper haircap moss is dominant are listed below.California
|Photo by Daniel Mosquin, courtesy of Creative Commons.|
Gametophyte: The gametophyte generation is the predominant and most conspicuous phase of juniper haircap moss's life cycle. Gametophytes consist of stems, leaves, and rhizoids . Growth form of juniper haircap moss gametophyte clusters is variable. Gametophytes typically form thin, interwoven mats. Less commonly, they grow as closely associated individuals or colonies [39,124] that sometime form distinct, globular masses (review by ). Relatively thick juniper haircap moss mats may have live stem tissue 2 to 3 inches (6-8 cm) below the mat surface. Surface stems translocate photosynthate to stems below the mat surface . Rhizoids extend down from stems, anchoring juniper haircap moss to its substrate [39,95,147]. When soil is the substrate, rhizoids may penetrate into mineral soil .
Juniper haircap moss stems are upright and unbranched in habit, growing from 0.4 to 4 inches (1-10 cm) tall [34,52]. The stems are a shiny bluish-green, resembling common juniper (Juniperus communis) leaves in color and shape . Stems are usually densely packed [57,116]. Juniper haircap moss is heterothallic, with male and female stems on separate plants. Male and female plants may grow in separate clumps  or intermingle . Male and female stems develop antheridia and archegonia, respectively, at their tips (see the Life cycle figure). Juniper haircap moss's leathery leaves are 4 to 8 mm long. They spread widely when moist, becoming narrower and more upright when dry. Leaf margins curve into the stem when dry, which probably reduces water loss [68,108,136] and enhances juniper haircap moss's ability to photosynthesize on xeric sites .
Sporophyte: Sporophytes grow out of archegonia. Juniper haircap moss sporophytes are large, generally about as tall as the female gametophytes to which they are attached [108,116]. The sporophyte consists of a foot that anchors the sporophyte to the archegonia, a stalk, and a 4-sided spore capsule. Juniper haircap moss's stalk is upright, wiry in texture, and unusually long compared to the stalks of most mosses; stalks range from 0.8 to 2 inches (2-6 cm) tall [34,108,124]. The spore capsule is 2.5 to 5 mm long. It is vertical when young, becoming horizontal with age. It has 64 blunt "teeth" at its top [34,124]. The spore capsule is capped with a hairy calyptra; the long hairs extend down the length of the entire capsule [34,124,136]. Spores are 6 to 12 µm in diameter [34,136]: relatively large compared to the spores of most moss species .
Physiology: Juniper haircap moss gametophytes continue photosynthesis and respiration when dry, although at much reduced rates . Faster rates of photosynthesis and respiration resume after gametophytes remoisten . In an Alaskan field study, juniper haircap moss had significantly higher rates of photosynthesis and respiration compared to 4 commonly associated mosses (P<0.05). Maximum rate of photosynthesis occurred from 68 to 86 °F (20-30 °C) for juniper haircap moss .
Osmosis is apparently the primary method of water conduction in juniper haircap moss  but is not the sole method. Haircap mosses (Polytrichaceae) have a well-developed system of small tubes that carry water from rhizoids to leaves [124,136], which allows for taller stem growth than is usual for most mosses.RAUNKIAER  LIFE FORM:
|Gametophyte dispersal and development: A spore is the first growth stage of a developing gametophyte [116,154]. The long hairs on the spore capsules help protect the developing gametophytes within from desiccation [34,124]. Spores within a single capsule usually mature synchronously . The calyptra breaks off when the spore capsule is mature, exposing the encapsulated spores. Release of the exposed spores requires dry weather and is governed by a row of hygroscopic teeth that ring the capsule's top. The capsule teeth bend outward when air is dry, which permits the spores to fall [116,136,154]. Dry winds disperse moss spores by shaking the capsule. When air is moist, the teeth bend inward, holding the spores within the capsule . Hausmann  and Reighard  describe archegonial and antheridial development and spore release at the cellular level. Wind dispersal of juniper haircap moss spores allows colonization on new sites [40,45,55,59,68,155]. Juniper haircap moss spores are very light in weight , and wind may carry the spores for long distances . The spores require a moist substrate to germinate [116,154].|
A germinated spore, or sporeling, develops into a protonema (a branched, threadlike structure) [116,154]. Nehlsen  describes protonema development at the cellular level. Rhizoids grow down from the protonema, often penetrating permeable substrates [116,154]. Protonema develop stem buds as they grow; stem buds sprout and develop into leafy gametophytes . As stems grow, they develop their own rhizoids and become independent of the protonema. Mature male and female stems develop antheridia and archegonia, which produce sperm and eggs, respectively [116,154]. In Margo Frankel Woods State Park, juniper haircap moss protonema and sporelings growing under litter were more likely to desiccate and die than protonema and sporelings in the open .
When mature, the tips of juniper haircap moss antheridia swell with water, and fluid accumulates at antheridia bases. Osmotic pressure at the tip and base of the antheridia forces sperm out [52,103]. Splashing rain or dew carry juniper haircap moss sperm to archegonia on female plants [52,116]. The sperm swim down the archegonia neck to the egg ; water is required to enable the sperm to swim . For information on development of juniper haircap moss sperm, see these sources: [2,104]. The sporophyte generation begins with the fertilized egg .
Spore banking: A soil-stored spore bank is possible for juniper haircap moss, but the spore bank may not be as important as newly-deposited, wind-blown spores. Based on research in pitch pinelands of New Jersey, Sedia and Ehrenfeld  suggest that freshly-dispersed spores are probably more important to juniper haircap moss establishment than soil-stored spores. In a greenhouse study, juniper haircap moss spores germinated in soil samples collected from a Norway spruce/downy birch (Picea abies/Betula pubescens) bog in Finland. Juniper haircap moss density on soil trays ranged from 16 to 48 sporelings/m² .
Breeding system: Juniper haircap moss is dioecious [52,116,136]. Male and female plants sometimes form separate colonies .
Juniper haircap moss shows genetic differences between populations. In the laboratory, juniper haircap moss from alpine populations in New Hampshire and from populations in an oak-hickory (Quercus-Carya spp.) forest in Indiana showed differences in photosynthetic rates under varying light conditions, with forest populations photosynthesizing under lower light conditions than the alpine populations .
Sporophyte development: Eggs are fertilized within the archegonium . After fertilization, the juniper haircap moss sporophyte embryo is partially parasitic on the gametophyte . The embryo grows rapidly, differentiating into foot, stalk, and spore capsule tissue . Gametophyte spores develop within the capsule .
Vegetative regeneration: Juniper haircap moss reproduces asexually from specialized gametophyte tissues and from plant breakage. Juniper haircap moss can sprout from rhizoids [65,147] and stem fragments [59,68,108]. Desiccated, whole or fragmented juniper haircap moss stems may regenerate from dormant stem buds after rehydration .
Growth: As of 2008, so few data were available on juniper haircap moss growth rates that conditions fostering or hindering growth were not apparent. Juniper haircap moss spores collected in Santa Cruz County, California, germinated 5 days after sowing in the laboratory. Protonema began developing 7 days after sowing, and rhizoids appeared after 7 to 14 days. Development was significantly slower at 64 °F (18 °C) than at 75 °F (24 °C) (P<0.05) . A laboratory experiment using soils from an Australian mountain-ash forest in Tasmania suggests that moderately-burned soil encourages the most rapid germination of juniper haircap moss spores, but that juniper haircap moss spores can germinate under a range of burned soil conditions. Soils were collected from 1- to 3-year-old burns representing a continuum of fire severities, from "severely burned" to unburned :
|Mean laboratory hours required for 50% of total germination of juniper haircap moss spores |
|Severely burned soil||58.53 (5.08)|
|Burned forest soil||94.79 (3.65)|
|Charred humus||61.67 (0.50)|
|Unburned forest soil||59.73 (1.80)|
|Unburned forest litter||57.56 (2.48)|
|Agar (control)||69.37 (0.47)|
Juniper haircap moss protonema had a mean radial growth rate of 1.65 mm/week in this laboratory study .
On the Edwin S. George Reserve, Michigan, juniper haircap moss stems spread horizontally 16 inches (40 cm) in one growing season, forming a mat. A network of stems extended 2 to 3 inches (6-8 cm) below the mat surface . In the Margo Frankel Woods State Park, Iowa, changes in juniper haircap moss stem lengths over 1 year ranged from 104% increase to 1.5% decrease in stem length. Mean change in stem length was a gain of 24.4% .SITE CHARACTERISTICS:
Substrates: Juniper haircap moss is most common on mineral soil [33,53,91,101] but also grows over rock [34,87,98], in humus  and peat [79,81,111], and on logs  and stumps [26,34,108]. In a black spruce forest in Ontario, juniper haircap moss occurred on sites with a 4-foot (1.3 m)- thick peat layer overlying clay . Juniper haircap moss is not an arboreal species . A vegetation survey in the Cascade Range of Oregon, for example, found juniper haircap moss growing on the forest floor and on logs, but not in trees .
Juniper haircap moss typically grows in habitats with "excessively dry to very dry" soils  and on soils with extremely fluctuating moisture levels . In white spruce forests of British Columbia, juniper haircap moss was most frequent growing on relatively dry sites over coarse morainal materials: microsite conditions where lodgepole pine tended to dominate . Juniper haircap moss is an indicator species of moisture-deficient sites in British Columbia [70,71], and Rowe  described juniper haircap moss as an indicator species of xero-mesophytic, fresh spruce forests of Saskatchewan and Manitoba. Morphological characteristics of the leaves (see General Botanical Characteristics) probably allow juniper haircap moss to inhabit dry sites where other mosses cannot easily grow . Juniper haircap moss is occasionally found on moist to wet sites. It was noted on very wet, mucky peat in a tamarack bog in southeastern Manitoba  and in marsh sod in New Jersey .
Juniper haircap moss usually grows on acidic soils [6,26,34] over a variety of parent materials. In a hybrid spruce (Picea glauca × P. engelmannii) forest of central British Columbia, juniper haircap moss occurred on moderately- to well-drained sands of morainal and colluvial parent materials. Soil pH averaged 4.6 . On black spruce sites in interior Alaska, juniper haircap moss occurred on soils ranging from 3.4 to 3.6 in pH and 3.6 to 5.6 inches (9.2-14.6 cm) in thickness of the 02 horizon. The soils overlay permafrost . In pitch pine barrens of New York, juniper haircap moss occurred on strongly acidic, deep sands overlying glacial outwash deposits and on rock pavement with parent materials of gneiss and sandstone .
When growing on soil, juniper haircap moss occurs on a variety of soil textures [23,101]. It occurred on fine-textured, sandy and gravelly soils in thermal basins of Yellowstone National Park, Wyoming. Soil temperatures where juniper haircap moss grew ranged from 95 to 140 °F (35-60 °C) 4 inches (10 cm) below the soil surface . Juniper haircap moss grows on sands in Indiana , shallow skeletal sands in the Sierra Nevada , and silts and coarse-textured soils in subalpine fir-Engelmann spruce forests of southeastern British Columbia .
Juniper haircap moss is characteristically found on disturbed substrates, especially burned soils [27,37,55,127]. It is well adapted to the large fluctuations summer temperature, high light levels, and low humidity levels that are typical of recently burned soils . In the laboratory, juniper haircap moss cover was positively correlated with high light conditions and high evaporation rates (P<0.001) . Heinselman  noted that on northern sites, juniper haircap moss is common on new burns where fire has consumed the organic soil layer. Juniper haircap moss colonized burned mineral soil after fires in northern Quebec , Kluane National Park, Yukon , and Yellowstone National Park, Wyoming . In Alberta, juniper haircap moss was noted on burned wood and soil substrates in postfire year 1 . It colonized burned peat on the Seward Peninsula of Alaska .
Juniper haircap moss is not commonly found on peat, but a few studies have noted juniper haircap moss in arctic and subarctic peatlands [6,74,111,139]. Macrofossil juniper haircap moss was a component of peat deposits on northern Ellesmere Island in the Northwest Territories . Timoney  described juniper haircap moss as an indicator species of dry peat bogs in Wood Buffalo National Park, Alberta.
Nutrients: Nonvascular plants, including juniper haircap moss, are generally more common on sites with low soil fertility than on productive sites (review by Hart and Chen ). Juniper haircap moss is an indicator species of nutrient-poor to nutrient-medium sites in coastal British Columbia [70,71]. In northern British Columbia, juniper haircap moss was more common in low-productivity quaking aspen stands than in productive stands . Analysis of vegetation patterns in a balsam fir-black spruce forests in Gros Morne National Park, New Brunswick, found juniper haircap moss was significantly associated with low calcium, low soil moisture, low pH levels, and moderate light levels (P=0.005) .
Juniper haircap moss and other mosses tend to enrich their substrates, allowing for establishment of later-successional species ( see Successional Status). In a study measuring nitrogen accumulation on a New Hampshire sandpit dominated by juniper haircap moss and globose haircap moss, Bowden  found the haircap mosses were "extremely efficient" at retaining nitrogen input, which came mostly from precipitation. Moss removal resulted in a rapid loss of soil nitrogen. The author found that nitrogen capture by haircap mosses facilitated growth of basidiomycete fungi and microbes in the soil. Accumulation of soil organic material was faster on sites with mosses, furthering the capacity of the site to retain nitrogen .
Elevation: Studies describing juniper haircap moss's elevational occurrences are too few to discern trends. Juniper haircap moss decreases with increasing elevation in coastal British Columbia . On the Washington Creek Fire Ecology Experimental Area near Fairbanks, Alaska, juniper haircap moss had greatest coverage (13.7%) in closed black spruce/splendid feather moss (Hylocomium splendens) forests at 2,600 to 3,440 feet (800-1,050 m) elevation and did not occur above 9,190 feet (2,800 m) elevation, where black spruce coverage was sparse . It was unclear from the study whether elevation or canopy cover was driving juniper haircap moss's relative abundance on the study sites. In a study on the western slope of the Cascade Range in central Oregon, juniper haircap moss was negatively correlated with high elevation; juniper haircap moss occurred from 1,700 to 2,200 feet (510-680 m) in a western hemlock-Douglas-fir forest .
Climate: Juniper haircap moss occurs in arctic, boreal, cool temperate, cool semiarid, and cool mesothermal climates. In British Columbia, juniper haircap moss occurrence increases with increasing continentality .SUCCESSIONAL STATUS:
Juniper haircap moss is most common on open sites with high light levels [14,108,116] but is moderately shade tolerant . Juniper haircap moss colonized bare areas of an alpine meadow in New Zealand. It was significantly more common in interior sections of the bare areas than on edges of bare areas (P<0.01). The authors suggested that higher light levels in interior portions of bare areas may have favored juniper haircap moss . In northern Ontario, juniper haircap moss frequency declined in jack pine and black spruce plantations with time since planting and canopy closure . There may be differences in light tolerance between populations. In the laboratory, juniper haircap moss plants collected in Indiana from a closed-canopy oak-hickory forest showed greater tolerance of low-light conditions than plants collected from an alpine Bigelow sedge (Carex bigelowiii) meadow in New Hampshire .
Primary succession: Several studies have noted juniper haircap moss occurrence in primary succession. Juniper haircap moss pioneers on granite outcrops in the Sierra Nevada . Windisch  found juniper haircap moss, swamp placynthiella lichen (Placynthiella uliginosa), and curly reindeer lichen (Cladonia cristatella) were primary successors on pitch pine plains in New Jersey, colonizing bare sand and gravel. Juniper haircap moss formed mats over rock depressions in a burnt-over western hemlock (Tsuga heterophylla)-Douglas-fir forest in coastal British Columbia , and formed tufts and mats over rock ledges in High Point State Park, New Jersey. Juniper haircap moss alone, or in combination with other mosses, often spread enough to eventually cover entire rock surfaces . Juniper haircap moss occurred on pumice substrates 18 years after the 1980 eruption of Mount St Helens in Washington. It also occurred in secondary succession on refugia that escaped the pumice flow; it is likely that spore sources for juniper haircap moss on the pumice sites came from refugia .
By colonizing bare substrates, juniper haircap moss sometimes facilitates establishment of later-successional species, and sometimes other species aid juniper haircap moss establishment. Juniper haircap moss and globose haircap moss pioneered on a New Hampshire sand pit, facilitating succession of soil biota  (see Site Characteristics for further details). However, on rock outcrops of boreal Manitoba, juniper haircap moss formed a tertiary mat over existing vegetation mats. It successionally followed pioneering low-growing lichens, which formed the first mat layer, and the secondary colonizers grimmia dry rock moss (Grimmia spp.) and twisted moss (Tortula ruralis), which grew over the lichen mat .
Disturbance: Juniper haircap moss is characteristically found on disturbed sites , especially burned soils (see Substrates). Steele  reported that juniper haircap moss was "opportunistic" in disturbed Douglas-fir forests of central Idaho, rarely occurring on undisturbed sites. Juniper haircap moss has persisted and/or colonized after plowing, windstorms, oil and mining exploration, construction, fire, and logging.
Juniper haircap moss may tolerate severe soil disturbance such as plowing, and often grows on abandoned agricultural lands. In a white spruce forest on the Cariboo Forest Region, British Columbia, discing and glyphosate treatments had no effect on juniper haircap moss cover and height compared with glyphosate treatment alone . Juniper haircap moss is common on old fields , growing, for example, on old fields in New Jersey .
Windstorms that expose soil may promote juniper haircap moss. One to 6 years after a tornado in an old-growth American beech-eastern hemlock (Fagus grandifolia-Tsuga canadensis) forest of northwestern Pennsylvania, juniper haircap moss was common on both windthrow plots and plots on the edge of undisturbed forest. Its mean cover was significantly (P<0.04) greater on windthrow (x=2.21%) than edge plots (x=0.54%) in 4 of 6 postdisturbance years .
Based on studies in the Northwest Territories, oil exploration and construction in northern zones may have less impact on juniper haircap moss than on many associated groundlayer species. A study of succession was conducted 48 years after construction of the CANOL Pipeline through bog birch-heath tundra. Juniper haircap moss was common in denuded vehicle track, borrow pit, and undisturbed areas [50,67]. It was also common on 5- to 22-year-old borrow pits that were used during construction of the Dempster Highway . Juniper haircap moss was the only moss to grow on experimental oil spills 1 year after oil-dump treatments on arctic and subarctic sites in the Mackenzie Delta [62,152].
Juniper haircap moss colonized strongly acidic, 5- to 38-year-old coal mine spoils in southern Iowa .
Fire: Juniper haircap moss is typically among the first groundlayer species to establish after fire (for example, [37,126,130,134,135]). It is characteristically found on burned mineral soils and other charred substrates [27,37]. A chronosequence study of soil profiles of black spruce habitats in Labrador, for example, found juniper haircap moss typically colonized burned mineral soil after fire in black spruce woodlands. Analysis of the humus layer showed that reindeer lichens dominated successionally after juniper haircap moss. Reindeer lichens were replaced successionally by Schreber's moss (Pleurozium schreberi) and Girgensohn's sphagnum (Sphagnum girgensohnii). The author noted that juniper haircap moss and/or fire moss often formed dense patches in depressions and mineral hollows created by postfire windthrow of black spruce. On average, coverage of juniper haircap moss peaked at 25% in postfire year 18. Juniper haircap moss dominated the ground layer through postfire year 25, when spineless reindeer lichen (Cladonia mitis) became more abundant. A black spruce/lichen woodland formed, on average, by postfire year 100, with a closed-canopy black spruce forest developing around postfire year 112 . Scotter  described similar postfire succession of groundlayer vegetation on black spruce sites that provide winter range for caribou in northern Saskatchewan:
In white spruce forests of Kluane National Park, Yukon, juniper haircap moss occurs in the woody plant seedling-herb stage of early postfire succession, which lasts from 1 to 15 years after fire. Stages that follow are: tall shrub/conifer sapling (postfire years 5-80), pole (postfire years 50-100), conifer woodland (postfire years 100-200), and mature white spruce forest (postfire years 150-400) .
Postfire colonization by juniper haircap moss and other mosses may increase the rate of succession over sites colonized by lichens. On the Lebanon State Forest of New Jersey, pitch pinelands subjected to either "hot" wildfires or sand mining were experimentally recolonized with either juniper haircap moss or reindeer lichen (Cladonia spp.) mats. Soils under juniper haircap moss accumulated more organic matter and had higher nitrogen levels than soils under reindeer lichens. The authors noted that vascular plants established more often on moss than on lichen mats; they attributed the more rapid rate of succession on juniper haircap moss mats to higher organic matter and nitrogen content . On nearby, naturally recolonized sites, juniper haircap moss and reindeer lichens occurred on open sites, with juniper haircap moss tending to colonize sites with relatively thicker organic soil horizons and greater shrub cover compared to sites where reindeer lichens colonized. Reindeer lichens grew over pioneering juniper haircap moss on some sites; 47% of lichen-dominated plots had dead juniper haircap moss and other mosses beneath the lichens, whereas none of the moss mats covered dead lichens. Moss and lichen mats in open areas tended to persist for decades. Both thick moss and thick lichen mats trapped seeds easily; however, germination and mycorrhizal infection rates of vascular plants were lower on lichen than on moss mats (P<0.001) .
Sphagnum mosses usually replaces juniper haircap moss successionally on burned peatlands, but reindeer lichens may succeed juniper haircap moss on some, probably drier, sites. In northern Quebec, the ground layers of 47-year-old black spruce-jack pine burns were dominated by juniper haircap moss, common haircap moss, and globose haircap moss, while sphagnum mosses dominated the ground layers on nearby 67-year-old burns . Reindeer lichens have replaced juniper haircap moss successionally in the Northwest Territories , Maine (review by ), New Jersey , and Jamaica .
See Plant Response to Fire for further information on postfire succession in ecosystems with juniper haircap moss.
Logging generally favors juniper haircap moss , probably by opening the canopy and reducing coverage of other groundlayer species. On sites representing a postlogging chronosequence in New Brunswick, juniper haircap moss occurred more often than expected (P<0.05) on clearcuts, heavily-thinned sites with small (<5 feet (1.5 m) tall) balsam firs, and in machinery tracks; but occurred less often than expected in relatively dense, mature spruce-balsam fir forest . In logged black spruce peatland forests of northeastern Ontario and western Quebec, juniper haircap moss was described as a widespread species with peak abundance (mean frequency >45%) on all logging sites studied, including nutrient-rich, nutrient-poor, horse-logged, and skidder-logged plots . In quaking aspen communities of northeastern British Columbia, juniper haircap moss was more common on 4-year-old logged sites than in 100-year-old forest; it grew on compacted and uncompacted soils on logged sites . In quaking aspen, jack pine, and black spruce forests in northern Minnesota, juniper haircap moss had greater mean coverage after logging (65.4%) than after wildfire (51.7%). Data were pooled across 2 age classes (25-40 and 70-100 years) and the 3 forest types (n=80 stands) . In logged subalpine fir-Engelmann spruce forests of southeastern British Columbia, juniper haircap moss had similar frequencies (52-56%) and cover (3.5-8.6%) on slash-burn sites, skid trails, and the downslope sides of skid trail banks. Its frequency (88%) and cover (27%) were much greater on the upslope, cutbank sides of skid trails compared to slash burns, skid trails, and downslope skid trail banks .
Studies on other continents demonstrate juniper haircap moss's widespread ability to colonize after logging. For example, juniper haircap moss dominated clearcuts in Finland. It was 2 to 8 times more abundant on 30-year-old clearcuts than in thinned, old-growth Scots pine (Pinus sylvestris) forests . Juniper haircap moss pioneered after logging in an Australian mountain-ash (Eucalyptus regans) forest in Tasmania. Juniper haircap moss was the dominant groundlayer species 5 years after tree harvest; it was the only species to colonize the "bare, compacted, and deeply puddled" tracks left by logging tractors .
Only 1 study reporting negative effects of logging on juniper haircap moss abundance was found in this literature review. In the Northwest Territories, juniper haircap moss was strongly negatively correlated with clearcuts and mechanical site preparation (various shearing and soil mixing treatments) on mixed-hardwood-white spruce sites on the Muskeg River Forest Demonstration Area, Northwest Territories .
Juniper haircap moss typically tolerates combinations of logging, fire, and conifer restocking. Moss cover was "almost completely destroyed" after an 80-year-old jack pine-tamarack forest in central Saskatchewan was clearcut, slash burned, and restocked with jack pine. Juniper haircap moss was the dominant moss in early postdisturbance succession, attaining greatest coverage on the driest sites. Juniper haircap moss coverage in postfire year 4 ranged from 10% to 40% on fresh soils and from 5% to 10% on moderately moist to moist soils . Also in central Saskatchewan, juniper haircap moss dominated the ground layer on jack pine sites that had been clearcut, slash burned, and restocked with jack pine and white spruce. Prior to treatments, Schreber's moss dominated the ground layer of the 80-year-old stands . Juniper haircap moss was an important moss 10 years after clearcutting followed by a wildfire and replanting of balsam fir in northwestern Newfoundland. Bunchberry (Cornus canadensis) was the dominant groundlayer species .
Near Thunder Bay, Ontario, juniper haircap moss and feather mosses colonized a plantation of red (Picea rubens), black, and white spruce. The plantation had formerly been an old field .
Late succession: Juniper haircap moss is generally uncommon after early succession, but a few studies note its presence in later stages of succession. It was listed among the "most abundant" native species in climax Sitka spruce (Picea sitchensis)-western hemlock forests on Olympic National Forest, Washington . In the Swan Valley of Montana, juniper haircap moss occurred in old-growth and second-growth mixed-conifer forests, although it was more frequent in second growth (5% vs. 2% frequency) . In a late successional, mixed-conifer-hardwood forest of northwestern Alberta, juniper haircap moss occurred with low frequency (0.26%) on disturbed patches on the forest floor but not on undisturbed patches of the forest floor, on logs, or on stumps . Juniper haircap moss was present on a 94-old-year catberry-highbush blueberry heathland that developed after a wildfire in central New York . The fire consumed over 3 feet (1 m) of peat in some areas (Ketchledge 1963, unpublished report cited in ).SEASONAL DEVELOPMENT:
Juniper haircap moss phenology in the United States
|Santa Cruz County, California||spores ripened in May |
|Margo Frankel Woods State Park, Iowa||gemetophyte growth began in mid-April with some fall regrowth on south slopes;
gametophytes under litter desiccated from September-November;
eggs fertilized during late September rains;
sporophytes emerged mostly in September and October but emerged in early April on one site 
|Illinois and Indiana||calyptra began splitting open in April;
spores dispersed in late May 
|Edwin S. George Reserve, Michigan||vegetative stem growth from March-June |
|Tompkins County, New York||immature antheridia present in late January;
antheridia matured after 2 weeks in greenhouse 
|Marathon County, Wisconsin|| embryonic calyptra present 28 February;
calyptra mature 31 August-22 September;
capsules ripened or spores dispersed 29 September 
Fire regimes: Juniper haircap moss occurs in ecosystems that experience frequent fire, such as pitch pine and jack pine, and in ecosystems which may experience fire-free intervals of 100 or more years, such as black spruce. Juniper haircap moss is generally common in ecosystems with short fire-return intervals. In plant communities with long fire-return intervals, it is generally frequent in early postfire succession and declines with canopy closure. Information on fire regimes in northern, northeastern, and western ecosystems where juniper haircap moss is common follow.
Spruce— Boreal black spruce forests have fire-return intervals ranging from about 50 to 100 years and experience both combination crown and ground fires [60,84]. Fires in spruce taiga may last for months, burning thousands to millions of acres . In Ontario, a black spruce-tamarack-northern white-cedar (Thuja occidentalis) forests burned at least once every 130 to 140 years ; fire-return intervals averaged 30 to 50 years for boreal forests in the area [73,85]. The area has relatively flat, uniform topography, and fires generally cover large areas. Juniper haircap moss was among the most common plant species on study plots that had burned 10 years previously . Black spruce-jack pine taiga forests in northwestern Manitoba have a long history of fire. McMinn  stated that it "is difficult to locate an area of homogeneous cover of more than 10 acres (4 ha) in the taiga (caribou) winter range, partly because of the incidence of forest fires and partly due to variable drainage". Estimated percentage of land burned annually over a 12-year period (1955-1967) was 0.17%. Fire-return intervals were not measured, although conifer stands in the area ranged from less than 60 to over 120 years old . A black spruce-jack pine forest in northern boreal Quebec experienced fire at intervals of 47 to 270 years. Juniper haircap moss, globose haircap moss, and common haircap moss dominated the forest floor on well-drained sites. Well-drained sites with haircap mosses tended to experience fires every 47 to 67 years: the short end of the fire-return interval range. The overstory was less dense on sites where haircap mosses dominated the ground layer than on sites dominated by sphagnum mosses; sphagnum-dominated sites were wetter and had longer fire-return intervals. Snag densities on one well-drained site that had burned 11 years previously ranged from 754 to 896 trees/ha .
White spruce forests of Kluane National Park, Yukon, have 150- to 400-year fire-return intervals. Juniper haircap moss occurs in the woody plant seedling-herb stage, which lasts from 1 to 15 years after fire. Mean fire-return interval increases with increasing latitude, from 133 years in the southern end of the Park, to 164 years in the middle of the Park, and 234 years in the northern end of the Park . Driscoll and others  reported a return interval of 140+ years for fires in hybrid spruce forests of central British Columbia.
Postfire succession proceeds slowly in black spruce forests near the northern treeline in the Northwest Territories. Juniper haircap moss was most common as a pioneer and early-successional species in open-canopy black spruce forests near treeline. Dominance of juniper haircap moss and other early-seral mosses declined about 120 years after fire, when reindeer lichens gained dominance .
In boreal ecosystems, fire-return intervals are generally longer in northeastern North America than further west. In southeastern Labrador, the fire-return interval for a black spruce-balsam fir/bog-laurel/Schreber's moss ((Kalmia polifolia/Pleurozium schreberi) forest was approximately 100 years, with an approximate 500-year fire rotation interval . The fire rotation was 3 to 10 times longer than fire rotations in the Great Lakes area . One black spruce stand on the site in southeastern Labrador had not burned in 230 years. Foster  attributed the long fire rotation in Labrador to abundant precipitation and extensive mires that serve as fuelbreaks.
Northeastern ecosystems: Pitch pine barrens have historically had short fire-return intervals, ranging from around 5 years on pitch pine plains to 80 years in mixed pitch pine-oak (Quercus spp.) forests . Juniper haircap moss cover and frequency tend to increase as fire-return intervals shorten (see Plant Response to Fire).
Western ecosystems: As of 2008, studies on juniper haircap moss's postfire occurrence in coniferous forests in western North America were lacking, so it is difficult to project what role fire plays in juniper haircap moss abundance in those forests. Juniper haircap moss is often noted in fir-spruce forests (see Habitat Types and Plant Communities), which have relatively long fire-free intervals compared to pine ecosystems. Arno  estimated fire-return intervals for subalpine fir-Engelmann spruce forests of the northern Rocky Mountains at 150+ years. Western hemlock forests of the west coast burn at intervals of 150 to 400 years (review by ). Research is needed on the relative importance of juniper haircap moss and other mosses after fire in conifer ecosystems of the western United States.
The following table provides fire regime information that may be relevant to juniper haircap moss. Find further fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find Fire Regimes".
|Fire regime information on vegetation communities in which juniper haircap moss may occur. For each community, fire regime characteristics are taken from the LANDFIRE Rapid Assessment Vegetation Models . These vegetation models were developed by local experts using available literature, local data, and/or expert opinion as documented in the PDF file linked from the name of each Potential Natural Vegetation Group listed below. Cells are blank where information is not available in the Rapid Assessment Vegetation Model.|
|Vegetation Community (Potential Natural Vegetation Group)||Fire severity*||Fire regime characteristics|
|Percent of fires||Mean interval
|Idaho fescue grasslands||Replacement||76%||40|
|Alpine and subalpine meadows and grasslands||Replacement||68%||350||200||500|
|Sitka spruce-western hemlock||Replacement||100%||700||300||>1,000|
|Douglas-fir-western hemlock (dry mesic)||Replacement||25%||300||250||500|
|Douglas-fir-western hemlock (wet mesic)||Replacement||71%||400|
|Mixed conifer (southwestern Oregon)||Replacement||4%||400|
|Surface or low||67%||22|
|California mixed evergreen (northern California)||Replacement||6%||150||100||200|
|Surface or low||64%||15||5||30|
|Lodgepole pine (pumice soils)||Replacement||78%||125||65||200|
|Pacific silver fir (low elevation)||Replacement||46%||350||100||800|
|Vegetation Community (Potential Natural Vegetation Group)||Fire severity*||Fire regime characteristics|
|Percent of fires||Mean interval
|Alpine meadows and barrens||Replacement||100%||200||200||400|
|California mixed evergreen||Replacement||10%||140||65||700|
|Surface or low||32%||45||7|
|Mixed conifer (North Slopes)||Replacement||5%||250|
|Surface or low||88%||15||10||40|
|Mixed conifer (South Slopes)||Replacement||4%||200|
|Surface or low||80%||10|
|Surface or low||74%||30|
|Sierra Nevada lodgepole pine (dry subalpine)||Replacement||11%||250||31||500|
|Surface or low||45%||60||9||350|
|Northern and Central Rockies|
|Vegetation Community (Potential Natural Vegetation Group)||Fire severity*||Fire regime characteristics|
|Percent of fires||Mean interval
|Northern and Central Rockies Grassland|
|Northern and Central Rockies Forested|
|Douglas-fir (xeric interior)||Replacement||12%||165||100||300|
|Surface or low||69%||28||15||40|
|Douglas-fir (warm mesic interior)||Replacement||28%||170||80||400|
|Persistent lodgepole pine||Replacement||89%||450||300||600|
|Lower subalpine lodgepole pine||Replacement||73%||170||50||200|
|Lower subalpine (Wyoming and Central Rockies)||Replacement||100%||175||30||300|
|Vegetation Community (Potential Natural Vegetation Group)||Fire severity*||Fire regime characteristics|
|Percent of fires||Mean interval
|Great Lakes Woodland|
|Great Lakes pine barrens||Replacement||8%||41||10||80|
|Surface or low||83%||4||1||20|
|Jack pine-open lands (frequent fire-return interval)||Replacement||83%||26||10||100|
|Northern oak savanna||Replacement||4%||110||50||500|
|Surface or low||87%||5||1||20|
|Great Lakes Forested|
|Conifer lowland (embedded in fire-prone system)||Replacement||45%||120||90||220|
|Great Lakes spruce-fir||Replacement||100%||85||50||200|
|Minnesota spruce-fir (adjacent to Lake Superior and Drift and Lake Plain)||Replacement||21%||300|
|Surface or low||79%||80|
|Great Lakes pine forest, jack pine||Replacement||67%||50|
|Surface or low||10%||333|
|Surface or low||76%||11||2||25|
|Surface or low||81%||85|
|Red pine-eastern white pine (frequent fire)||Replacement||38%||56|
|Surface or low||26%||84|
|Great Lakes pine forest, eastern white pine-eastern hemlock (frequent fire)||Replacement||52%||260|
|Surface or low||35%||385|
|Vegetation Community (Potential Natural Vegetation Group)||Fire severity*||Fire regime characteristics|
|Percent of fires||Mean interval
|Rocky outcrop pine (Northeast)||Replacement||16%||128|
|Surface or low||52%||40|
|Surface or low||65%||12|
|Oak-pine (eastern dry-xeric)||Replacement||4%||185|
|Surface or low||90%||8|
|Appalachian oak forest (dry-mesic)||Replacement||2%||625||500||>1,000|
|Surface or low||92%||15||7||26|
|Northeast spruce-fir forest||Replacement||100%||265||150||300|
|Vegetation Community (Potential Natural Vegetation Group)||Fire severity*||Fire regime characteristics|
|Percent of fires||Mean interval
|Southern Appalachians Woodland|
|Table Mountain-pitch pine||Replacement||5%||100|
|Surface or low||92%||5|
|Appalachian Virginia pine||Replacement||20%||110||25||125|
|Surface or low||64%||35||10||40|
Replacement: Any fire that causes greater than 75% top removal of a vegetation-fuel type, resulting in general replacement of existing vegetation; may or may not cause a lethal effect on the plants.
Mixed: Any fire burning more than 5% of an area that does not qualify as a replacement, surface, or low-severity fire; includes mosaic and other fires that are intermediate in effects.
Surface or low: Any fire that causes less than 25% upper layer replacement and/or removal in a vegetation-fuel class but burns 5% or more of the area [49,75].
Density and biomass measurements of juniper haircap moss may provide baselines for juniper haircap moss fuel loads and/or rates of postdisturbance biomass accumulation on similar sites. On the Edwin S. George Reserve, Michigan, juniper haircap moss had a mean density of 127.84 stems/cm²/39 cm² plot and mean cover of 83.46 cm²/39 cm² plot . Biomass in 4 unburned sheathed cottonsedge (Eriophorum vaginatum) tundra communities of Alaska and the Northwest Territories averaged 516 g/m²; total moss cover averaged 22%. Juniper haircap moss was the dominant moss on burned sites in postfire year 1, averaging 2% cover across sites . Seven years after construction of a powerline in northern Manitoba, aerial biomass of vegetation on disturbed sites was less than 40% of aerial biomass on undisturbed sites. Dark sphagnum moss (Sphagnum fuscum) and juniper haircap moss dominated both disturbed and undisturbed plots; juniper haircap moss frequency was 46% on undisturbed plots and 30% on disturbed plots .
|Aboveground biomass of vegetation on undisturbed and disturbed plots 7 years after powerline construction in northern Manitoba |
|juniper haircap moss||4||5|
POSTFIRE REGENERATION STRATEGY (adapted from ):
Vegetative propagules on soil surface
Ground residual colonizer (on-site spores, initial community)
Secondary colonizer (on- or off-site spore sources)
Juniper haircap moss is frequently included in a small group of groundlayer species that obtain high frequencies in early postfire communities (for example, [134,135]). In a review, Wein  identified juniper haircap moss and Marchantia polymorpha as "the first cryptogams to emerge" after tundra fires in Alaska and Canada. In spruce forests of the Northwest Territories, juniper haircap moss, common haircap moss, and fire moss were called "the most efficient" at vegetative reproduction in early postfire succession among 9 bryophytes studied . Juniper haircap moss and common haircap moss were described as "covering the soil" (80% cover) 4 years after experimental fires in a Scots pine-Norway spruce forest in Sweden .
Juniper haircap moss generally colonizes soon after fire, declining within 5 to 15 postfire years in most North American ecosystems [1,30,42,53,57,68,129]. Juniper haircap moss's appearance in early postfire succession has been documented across its distribution. In a review, Ryoma and Laaka-Lindberg  note that juniper haircap moss is most common from postfire years 1 through 4 in diverse locations and plant communities including coastal heath dunelands of Denmark, heathlands of Scotland and France, coniferous forests of Europe and North America, tropical mountain associations in Jamaica, and eucalyptus forests of Australia. Worldwide, juniper haircap moss occurrence generally declines after 10 to 20 postfire years . The following sections provide information on juniper haircap moss postfire establishment across juniper haircap moss's North American distribution. The sections are arranged geographically from north to south and west to east, followed by studies of postfire juniper haircap moss establishment outside North America.
Northern ecosystems: Juniper haircap moss and other haircap mosses colonized burned areas at low to high densities after tundra wildfires on the Seward Peninsula of Alaska. Haircap mosses had 0% to 1% total prefire coverage on permanent study plots in tussock sedge (Carex spp. and sheathed cottonsedge)-heath-dwarf birch and heath-dwarf birch communities a year before wildfires in 1977. Prefire density was not measured. In postfire year 1, haircap mosses grew on charred peat surfaces at densities ranging from less than 1 to 81 stems/m². Juniper haircap moss was the dominant moss on 2 nearby tussock sedge-mixed shrub sites that had burned 7 years previously, with total haircap moss density averaging 135 stems/m² on the 7-year-old burns [111,112].
Juniper haircap moss and other haircap mosses often dominate early postfire succession in spruce taiga forests of interior Alaska and northern Canada, first appearing approximately 3 months to 3 years after fire. The moss-herb stage of postfire succession, which often includes juniper haircap moss, lasts about 10 years . In the Mackenzie Delta in the Northwest Territories, juniper haircap moss was the only groundlayer species that "regrew" 1 and 2 years after wildfires. The study sites were in black spruce-tundra ecotone and marsh Labrador tea (Ledum palustre ssp. decumbens)/sheathed cottonsedge tundra communities .
Juniper haircap moss and other early-seral groundlayer species typically form postfire assemblages across moisture and other gradients; postfire successional trajectories of these assemblages may be difficult to predict. Reindeer lichens [37,91], Marchantia polymorpha, fireweed , fire moss, and other haircap mosses are common juniper haircap moss associates on burned spruce taiga . Because juniper haircap moss is taller in stature and more drought tolerant, it successionally replaces fire moss on many burned sites . In a review, Lutz  described juniper haircap moss as rare to abundant in early-successional, burned black spruce, paper birch, and quaking aspen forests in southwestern and central interior Alaska. Juniper haircap moss often replaced pioneering fire moss and Pohlia spp. mosses, with juniper haircap moss cover peaking about 10 to 20 years after fire. In turn, juniper haircap moss was often replaced by reindeer lichens and Schreber's moss . However, in a chronosequence study of burned black spruce stands in interior Alaska, fire moss gained dominance over juniper haircap moss in early postfire succession. Juniper haircap moss grew in young (3-, 7-, and 10-year-old) stands but never attained over 4% cover, while fire moss showed 35% to 59% cover in young stands. Neither moss was found in older stands .
Juniper haircap moss was the dominant moss in black spruce and quaking aspen communities 3 years after the Wickersham Dome Fire near Fairbanks. It was more frequent in black spruce than quaking aspen communities :
|Juniper haircap moss density and frequency on severely burned sites following the Wickersham Dome Fire near Fairbanks, Alaska, in summer 1971 |
|Density (stems/ha)||Frequency (%)|
|Black spruce forest|
|1972 (postfire year 1)||0.40||40|
|1973 (postfire year 2)||0.65||65|
|1974 (postfire year 3)||5.10||45|
|Adjacent unburned control||1.70||65|
|Quaking aspen forest|
|1972 (postfire year 1)||0.05||5|
|1973 (postfire year 2)||0.05||5|
|1974 (postfire year 3)||1.40||65|
|Adjacent unburned control||0.20||10|
Hawkes  observed juniper haircap moss soon after fire in white spruce forests of Kluane National Park, Yukon; juniper haircap moss colonized mineral soil in postfire years 1 to 15 . It was among the most common mosses of early postfire succession in the 1st and 2nd growing season after a wildfire in a black spruce muskeg in northeastern Alberta. Juniper haircap moss was more common on unlogged, burned soils than on other substrates in postfire year 1, but juniper haircap moss frequencies were similar on unlogged and salvage-logged burned soils by postfire year 2 .
|Frequency (%) of juniper haircap moss on burned wood or scorched soil the 1st and 2nd growing seasons after a wildfire in Alberta |
|Postfire year 1
|Postfire year 2
|burned and salvage logged||20.8||29.2|
Soil (includes mineral and organic soils)
|burned and salvage logged||38.9||66.7|
In a chronosequence study of burned hybrid spruce/devil's club (Oplopanax horridus)/moss sites in central British Columbia, juniper haircap moss was the dominant moss in early postfire succession (<14 years after fire), with average cover of 35% .
Analyses of 141 black spruce-jack pine stands in the Slave Lake area of the Northwest Territories found juniper haircap moss was associated with stands that had burned 10 or fewer years previously. Juniper haircap moss, fire moss, and fireweed formed an "eclectic group which seems to reflect survival and regeneration from the prefire vegetation" . Juniper haircap moss cover was similar among burns of different ages in the Northwest Territories :
|Juniper haircap moss abundance on different-aged burns on black spruce/bog birch peat plateaus of Chick Lake Basin, Northwest Territories |
|Postfire year||Cover (%)||Frequency (%)|
In the Mackenzie Valley, Northwest Territories, juniper haircap moss dominated the moss layer of a white spruce/splendid feather moss habitat type that burned 30 years prior to plant surveys. Quaking aspen, meadow horsetail (Equisetum pratense), and juniper haircap moss had 2% cover each; no other plant and no lichen species had gained more than 2% cover by postfire year 30. Juniper haircap moss was also a dominant moss on a dwarf heathland/herb community in Mackenzie Valley that burned in 1911 and reburned in 1968, showing 1% cover 5 years after the 1968 fire .
A chronosequence study of black spruce/reindeer lichen woodlands in northern Quebec found juniper haircap moss and other early-successional mosses colonized mineral soil, with a black spruce woodland forming about 65 years after fire. Postfire succession proceeded as follows :
|Postfire chronosequence development of black spruce forests in northern Quebec |
|Postfire year||Dominant species|
|4||juniper haircap moss-globose haircap moss-fire moss|
|14||granular trapeliopsis lichen (Trapeliopsis granulosa)|
|38||spineless reindeer lichen|
|42||star reindeer lichen (Cladonia alpestris)|
|65||star reindeer lichen-immature black spruce|
|129||black spruce/star reindeer lichen woodland|
|250||black spruce/Schreber's moss-hairy ptilidium liverwort (Ptilidium ciliare) forest|
Analyses of soil profiles from burned black spruce woodlands in Labrador showed juniper haircap moss was the first moss to establish after surface, shallow, and deep peat fires. On sites with deep peat fire, juniper haircap moss grew over a layer of mineral soil and charcoal. On sites where fire consumed only the upper peat layer, juniper haircap moss grew over a layer of reindeer lichens (Cladonia spp.). On some of these sites, the reindeer lichens had in turn grown over a layer of juniper haircap moss in the lower peat profile. Juniper haircap moss in the lower layer overlaid charcoal and mineral soil .
In a 38-year chronosequence study, postfire coverage of juniper haircap moss peaked in postfire year 4 but fluctuated across study years. Study sites were located in black spruce/sheep-laurel (Kalmia angustifolia) habitats in Newfoundland .
|Mean juniper haircap moss coverage after fires in Terra Nova National Park, Newfoundland |
|Postfire year||Cover (%)|
Northeastern ecosystems: Juniper haircap moss may colonize relatively dry sites in areas where other haircap mosses cooccur. Four years after a wildfire in a mixed-hardwood stand on Mt Desert Island, Maine, juniper haircap moss and globose haircap moss formed discontinuous swards in valleys and on hilltops. Globose haircap moss tended to grow in wet depressions, while juniper haircap moss grew on drier microsites .
Juniper haircap moss attains generally high cover in the frequent fire-return intervals typical of pitch pinelands. On pitch pine plains in New Jersey, fire-return intervals range from 5 to 60 years. The fire regime in pitch pine communities is mixed, with surface fires occurring in the low end of the range and stand-replacement crown fires in stands where fire has not occurred for many decades. Old, closed-canopy pitch pine stands with a shrub understory are most likely to experience crown fire. Juniper haircap moss is common on such severely burned sites, apparently establishing from wind-dispersed spores . Frequent, prescribed surface fires also favored juniper haircap moss on a New Jersey pitch pine barrens site. Postfire inventories on sites burned under prescription showed juniper haircap moss, fire moss, and broom dicranum moss (Dicranum scoparium) comprised 98% of total moss cover on 3-year or annual-burn rotations. Overall moss cover at postfire year 3 was 29% and lichen cover was 19%. Annual burning reduced the moss and lichen ground layer compared to 3-year fire-return intervals, with 9% total moss cover and 8% total lichen cover on annually-burned plots . Fourteen years after a "hot" wildfire on the Lebanon State Forest in New Jersey, juniper haircap moss and reindeer lichens dominated open areas within young pitch pine-oak stands .
Western ecosystems: Juniper haircap moss was more abundant on 29-year-old burns than on unburned sites in subalpine fir-mountain hemlock/pink mountainheath-Cascade bilberry (Tsuga mertensiana/ Phyllodoce empetriformis-Vaccinium deliciosum) krummholz and pink mountainheath-Cascade bilberry-heather (Cassiope mertensiana) alpine heath communities of the North Cascade Range, Washington. Juniper haircap moss and Tolmie's penstemon (Penstemon procerus var. tolmiei) had highest postfire coverage (8% each) compared to other plant species in the krummholz community .
|Mean percent cover and frequency of juniper haircap moss on burned and unburned alpine plant communities of the North Cascade Range, Washington |
|Cover (%)||Frequency (%)||Cover (%)||Frequency (%)|
A study in a bluebunch wheatgrass-Idaho fescue community in Hell's Canyon National Recreation Area, Oregon, found wildfire had no significant effect on cover of moss and lichen cryptogamic soil crusts. Juniper haircap moss was not present on unburned plots but had 0.3% cover on wildfire-burned plots in postfire month 11 . Fire may have favored formation of cryptogamic soil crusts in Yellowstone National Park. Thirteen years after the 1988 fires, juniper haircap moss and globose haircap moss had formed mats over dry mineral soil. The study sites had been lodgepole pine forest before the stand-replacement fires .
Outside North America: After reaching peak cover in early postfire decades, juniper haircap moss declined with time since fire in Finland studies. Juniper haircap moss generally colonized in postfire year 3 on Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) sites burned under prescription. Time since fire ranged from 1 month to 50 years in the study area. In Norway spruce stands, juniper haircap moss first occurred in postfire year 3, following common dandelion (Taraxacum officinale) and fireweed. Juniper haircap moss dominated the moss strata of 3-year-old burns in both forest communities, with juniper haircap moss and other haircap mosses comprising nearly 100% of total moss cover. Haircap mosses reached maximum frequency in postfire years 4 to 9. On 30-year-old plots, juniper haircap moss and other haircap mosses comprised 40% of total moss cover. On 50-year-old burns, haircap moss comprised 4% of total moss cover. Haircap mosses had 1% cover on unburned sites .
Juniper haircap moss dominated the groundlayer vegetation 21 years following prescribed burning in a Norway spruce peatland forest in northern Sweden. Splendid feather moss and Schreber's moss dominated before the fire. The fire removed an average thickness of 0.5 inch (1.3 cm) of peat [143,144].
Some Scottish heathlands have been burned for centuries for rangeland management. There are anecdotal reports of juniper haircap moss dominating on heath rangelands where prescribed fire "got entirely out of control" and burned into the peat layer, smoldering for "days or weeks". Areas denuded by such peat fires are typically colonized by juniper haircap moss, other mosses, and lichens . On a heather (Calluna vulgaris) heathland on the Muir of Dinnet National Nature Preserve, Scotland, juniper haircap moss was not present on study plots prior to a prescribed fire but had 8% frequency in postfire year 1 .
On heathlands in France, juniper haircap moss typically establishes soon after fire but grows "slowly" compared to associated groundlayer species [42,43].
Juniper haircap moss was 1 of 3 early-seral mosses occurring after fire in an Australian mountain-ash forest in Tasmania [18,25]. Cord moss (Funaria hygrometrica), fire moss, and Marchantia polymorpha dominated the burn in postfire years 1 and 2, with scattered colonization by juniper haircap moss. Juniper haircap moss grew more slowly than the initial groundlayer dominants, but became dominant on sites where taller, herbaceous species were not present by postfire year 3.5. It remained dominant, with approximately 50% cover, on open sites through at least postfire year 6.5 . On another Australian mountain-ash forest in Tasmania, juniper haircap moss first occurred on study plots in postfire year 2. By postfire year 4, juniper haircap moss had successionally replaced fire moss and cord moss .
Fire and logging: Several studies show that juniper haircap moss is tolerant of fire and logging. See Logging and Discussion and Qualification of Plant Response for further information on this topic.DISCUSSION AND QUALIFICATION OF PLANT RESPONSE:
For information on prescribed fire and postfire response of many plant species, including juniper haircap moss, see these Research Project Summaries:
Waterfowl may avoid sites where juniper haircap moss is dominant because those areas are relatively dry .
Palatability/nutritional value: Mosses in general are low in nutritional value compared to associated groundlayer species. Even compared to other mosses, juniper haircap moss was low in nitrogen and other nutrients on a burned Australian mountain-ash forest in Tasmania. Brasell and Mattay  provide a nutritional analysis of juniper haircap moss on that site.
Cover value: Wildlife seeking hiding or thermal cover probably avoid open areas dominated by juniper haircap moss or other low vegetation.
Woodland caribou in the Mackenzie and Selwyn Mountains of Yukon and the Northwest Territories use snowfields within arctic dryad-red fruit bearberry (Dryas integrifolia-Arctostaphylos rubra) tundra cushion plant communities as relief habitat to escape insect harassment. Juniper haircap moss is a common moss in that habitat .VALUE FOR REHABILITATION OF DISTURBED SITES:
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