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Wildlife, Animals, and Plants
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Introductory
SPECIES: Juniperus horizontalis | Creeping Juniper
ABBREVIATION :
JUNHOR
SYNONYMS :
NO-ENTRY
SCS PLANT CODE :
JUHO2
COMMON NAMES :
creeping juniper
creeping cedar
TAXONOMY :
The currently accepted scientific name of creeping juniper is Juniperus
horizontalis Moench. Creeping juniper is noted for its wide
morphological variation [1,13]. In some instances, variation within a
single colony can be as great as within the species as a whole [1,13].
Creeping juniper generally exhibits distinctive characteristics except
in certain locations where it occurs with eastern redcedar (J.
virginiana) [35] or Rocky Mountain juniper (J. scopulorum) [13]. Here,
intergradation or individuals with intermediate characteristics occur,
as creeping juniper readily hybridizes with both of these species.
Creeping juniper hybridizes with eastern redcedar on the eastern edge of
the driftless area of Wisconsin, along the coast of Maine, and in New
York [16,35]. Hybrid swarms made up of junipers with characteristics
intermediate between the two species occur in these areas [13,31].
Creeping juniper also readily hybridizes with Rocky Mountain juniper in
areas of overlap [7,15]. Such hybrids have been described in parts of
Montana and in southern Alberta [2]. These hybrids typically exhibit a
number of intermediate characteristics [7,15], although researchers
report that growth habit is a good indicator of hybridization between
creeping juniper and Rocky Mountain juniper [2]. These hybrids occur as
decumbent shrubs with foliage mostly resembling that of Rocky Mountain
juniper. Hybrids between creeping juniper and eastern redcedar and
between creeping juniper and Rocky Mountain juniper have been treated as
separate varieties: J. v. var. ambigens Fassett and J. v. var. patens
Fassett, respectively [1,2]. This treatment is no longer followed by
the majority of taxonomists [2].
LIFE FORM :
Shrub
FEDERAL LEGAL STATUS :
No special status
OTHER STATUS :
NO-ENTRY
COMPILED BY AND DATE :
D. Tirmenstein, December 1988.
LAST REVISED BY AND DATE :
NO-ENTRY
AUTHORSHIP AND CITATION :
Tirmenstein, D. A. 1988. Juniperus horizontalis. In: Remainder of Citation
DISTRIBUTION AND OCCURRENCE
SPECIES: Juniperus horizontalis | Creeping Juniper
GENERAL DISTRIBUTION :
Creeping juniper is widely distributed across Canada from the Atlantic
to the Pacific Coast [7]. It is particularly widespread in North
America near the northern limit of trees [27]. Creeping juniper occurs
from Newfoundland westward to British Columbia, the Yukon, and Alaska
[27]. Its range extends southward to Montana, Wyoming, and northern
Colorado and east to northeastern Iowa, northeastern Illinois, New York,
and Massachusetts [27].
Evidence suggests that a dry period which occurred 7,000 to 8,000 years
ago enabled creeping juniper to extend its range into North and South
Dakota, and Montana [2].
ECOSYSTEMS :
FRES20 Douglas-fir
FRES21 Ponderosa pine
FRES28 Western hardwoods
FRES29 Sagebrush
FRES34 Chaparral - mountain shrub
FRES36 Mountain grasslands
FRES38 Plains grasslands
FRES39 Prairie
STATES :
AK IL IA ME MA MI MN MT NE NY
ND SD VT WI WY AB BC MB NB NF
NT NS ON PE PQ SK YT
ADMINISTRATIVE UNITS :
ACAD BADL EFMO FIIS GATE GLAC
ISRO SLBE THRO WICA
BLM PHYSIOGRAPHIC REGIONS :
8 Northern Rocky Mountains
9 Middle Rocky Mountains
10 Wyoming Basin
14 Great Plains
15 Black Hills Uplift
16 Upper Missouri Basin and Broken Lands
KUCHLER PLANT ASSOCIATIONS :
K011 Western ponderosa forest
K012 Douglas-fir forest
K016 Eastern ponderosa forest
K018 Pine - Douglas-fir forest
K040 Saltbush - greasewood
K055 Sagebrush steppe
K056 Wheatgrass - needlegrass shrubsteppe
K063 Foothills prairie
K064 Grama - needlegrass - wheatgrass
K065 Grama - buffalograss
K066 Wheatgrass - needlegrass
K081 Oak savanna
K098 Northern floodplain forest
SAF COVER TYPES :
42 Bur oak
210 Interior Douglas-fir
219 Limber pine
235 Cottonwood - willow
236 Bur oak
237 Interior ponderosa pine
SRM (RANGELAND) COVER TYPES :
NO-ENTRY
HABITAT TYPES AND PLANT COMMUNITIES :
Creeping juniper is an indictor in a number of grassland or drier
coniferous forest habitat types of the northern Great Plains. It occurs
most commonly as a codominant with little bluestem (Schizachyrium
scoparium) or sun sedge (Carex heliophila) in plains grassland habitat
or community types [10,21,22,24]. Creeping juniper frequently occurs as
an understory dominant with limber pine (Pinus flexilis) in certain
habitat types of southwestern North Dakota [10]. Publications listing
creeping juniper as an indicator are as follows:
Native woodland ecology and habitat classification of southwestern
North Dakota [10]
The vegetation of the Grand River/Cedar River, Sioux, and Ashland
Districts of the Custer National Forest: a habitat type
classification [21]
The vegetation of Theodore Roosevelt National Park, North Dakota: a
habitat type classification [22]
VALUE AND USE
SPECIES: Juniperus horizontalis | Creeping Juniper
WOOD PRODUCTS VALUE :
The wood of creeping juniper is soft, open grained, and reddish brown
with wide white sapwood [36]. The wood currently has no commercial
value.
IMPORTANCE TO LIVESTOCK AND WILDLIFE :
Creeping juniper foliage provides some forage for deer, elk, bighorn
sheep, and pronghorns [17,28]. Generally this species is used only in
trace amounts, but utilization may be heavy in some areas, particularly
during the winter [17,28]. The foliage of creeping juniper is
apparently of little value to domestic livestock.
In many areas, mule deer begin utilizing creeping juniper in late
December or January and continue feeding on the foliage until March or
April [28]. Variable use of creeping juniper has been reported in
eastern and central Montana during the winter, although no summer use
has been observed [28]. Creeping juniper was the single most important
spring food of mule deer in parts of north-central Montana [41]. In
some locations, creeping juniper browse represented up to 41 percent of
the mule deer's diet during March and April [41]. White-tailed deer
utilize creeping juniper lightly in winter in eastern and north-central
Montana [28]. Trace amounts of creeping juniper have been found in the
winter diets of elk and bighorn sheep in Montana [28]. In some areas,
including parts of the northern Great Plains, creeping juniper may be a
relatively important food item for pronghorns [28]. This browse may be
particularly important during the late fall, winter and early spring.
Creeping juniper browse comprised up to 10 percent of pronghorn diets
during the winter and was the dominant food plant from December through
March in parts of Saskatchewan [42]. Pronghorns in the Canadian Great
Plains frequently winter in steep, eroded areas dominated by silver
sagebrush (Artemisia cana) and creeping juniper [42].
Berries of most juniper species are excellent sources of food for many
small birds and mammals. Berries often remain on the plants for 1 to 2
years thus constituting a readily available food source in some areas.
Creeping juniper berries are an important food of both immature and
adult sharp-tailed grouse [28]. In parts of Montana 49 to 70 percent of
grouse crops contained juniper berries which represented 25 to 40
percent of the total food volume [28]. In some areas, creeping juniper
berries are the second most important food item for sharp-tailed grouse
[28].
PALATABILITY :
Creeping juniper is most palatable to large ungulates during the winter
[17,28,41,42]. The levels of unpalatable terpenes peak during the
summer [38]. Lowest terpene levels occur from September to April [38],
coinciding with the period of peak palatability. The terpene content of
individual creeping junipers is believed to be extremely variable [38].
This variation may perhaps help to explain some of the reported
differences in palatability levels by geographic area.
The palatability of creeping juniper to livestock and wildlife species
in several western states has been rated as follows [9]:
MT ND WY
Cattle poor ---- poor
Sheep poor ---- poor
Horses poor ---- poor
Pronghorn ---- good ----
Elk poor ---- ----
Mule deer good good ----
White-tailed deer ---- fair ----
Small mammals fair fair ----
Small nongame birds fair good ----
Upland game birds poor good ----
NUTRITIONAL VALUE :
Creeping juniper is rated poor in overall protein and energy value [9].
COVER VALUE :
Creeping juniper provides only minimal cover for larger birds and
mammals because of its small size. It may provide limited cover for a
number of small birds and mammals. The degree to which creeping juniper
provides environmental protection during one or more seasons for
wildlife species has been rated as follows [9]:
MT ND
Pronghorn poor ----
Mule deer poor poor
White-tailed deer ---- poor
Small mammals fair poor
Small nongame birds fair poor
Upland game birds fair poor
VALUE FOR REHABILITATION OF DISTURBED SITES :
Creeping juniper has moderate to high potential for long-term
rehabilitation and low potential for short-term rehabilitation [9]. Its
ability to grow well on many harsh sites and its tendency to form solid
mats make it useful in preventing soil erosion [9,36].
OTHER USES AND VALUES :
Creeping juniper has been widely used for horticultural purposes. The
low creeping growth form of this plant makes it well adapted for use as
a ground cover or ornamental [7,39]. It is often grown in strips along
curbs or sidewalks [39] and can aid in reducing soil erosion on harsh
sites [36]. A number of horticultural forms have been developed
including the cultivar 'Plumosa compacta' [11], a deep bluish phase
Juniperus horizontalis var. douglasii, and a variegated phase Juniperus
horizontalis var. variegata Beissn. [23].
MANAGEMENT CONSIDERATIONS :
Creeping juniper increases in response to overgrazing in rough fescue
(Festuca scabrella) communities of western Montana [29]. Butler [6]
reported highest cover and frequency values for creeping juniper on
moderate or heavily grazed green ash (Fraxinus pennsylvanica) draws of
the North Dakota Badlands as shown below:
cover% relative frequency relative importance
cover % % freq. % value
lightly grazed -- -- -- -- --
mod. grazed 3.90 4.66 5.78 1.14 5.80
heavily grazed 4.23 3.44 5.29 1.17 4.61
While moderate levels of grazing have little effect on creeping juniper,
extremely high livestock utilization can injure or kill plants in some
locations [28].
Application of fertilizers in the field may increase fruit production of
creeping juniper, although it appears to have little effect on overall
productivity [28].
BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Juniperus horizontalis | Creeping Juniper
GENERAL BOTANICAL CHARACTERISTICS :
Creeping juniper is a slow-growing, native, prostrate, mat-forming shrub
[5,20]. Creeping juniper usually grows to less than 8 to 12 inches (20-
30 cm); mats can grow up to 23 feet (7 m) across [23,26]. Plants which
are somewhat taller may occur in some locations where browsing inhibits
peripheral spread or where disease promotes abnormal growth [28]. Stems
of creeping juniper may be decumbent, procumbent, or prostrate [39].
The trailing stems are capable of rooting at nodes, producing
adventitious roots at irregular clusters [5,36].
Older branches are dark reddish brown to gray, whereas younger twigs are
reddish brown to yellow [20]. The bark is reddish brown and exfoliates
into thin flakes or strips [36]. Creeping juniper varies in color and
morphology. Plants range from a bright green to dark green, yellow
green, or glaucous [13,20]. Leaves are opposite and scalelike at
maturity but more acicular when young [13,36].
Staminate cones are pale brown or yellowish, ripening to purple, and
cylindrical to ellipsoid [20,28]. Cones or fruits are globose and
green, ripening to a glaucous, bluish purple or bluish black [36,39].
The berrylike fruits are succulent and contain two to six reddish-brown,
ovoid to round seeds [20,23,28,36,39].
RAUNKIAER LIFE FORM :
Phanerophyte
Chamaephyte
Hemicryptotphyte
REGENERATION PROCESSES :
Evidence suggests that creeping juniper rarely reproduces by seed [28].
It can readily root along horizontally spreading branches or leaders
[28]. The majority of new plants are formed by the breakup of older
shrubs [28].
Creeping juniper is dioecious [36] and produces berries which mature in
either 1 or 2 years [20,23,39]. Stephens [36] reported that cones are
fertilized in the spring of one season and reach maturity by the fall of
the following growing season.
Germination of creeping juniper seeds is poor. Miller [28] reported
that only nine of approximately 9,500 new and 2-year-old seeds
germinated. The seeds of most species of juniper must undergo a
distinct period of rest and afterripening [30]. Juniper seeds which
have not undergone afterripening generally exhibit very low germination
rates (approximately 1%) [30]. Juniper seeds are semipermeable with a
thick seedcoat [30]. Most juniper seeds are apparently resistant to
damage, and germination may actually be enhanced by disgestive processes
[3,10]. Many small mammals, birds, and deer consume creeping juniper
seeds and serve as dispersal agents [28].
SITE CHARACTERISTICS :
Creeping juniper occurs on open prairies; dry, rocky hillsides; mountain
foothills; open woods; rock ledges or escarpments; dry montane ridges
and hilltops; and in wash areas [20,23]. This species is capable of
growing on dry, harsh, eroded sites or exposed pavement [28,36,37,42].
Creeping juniper commonly grows on thin, poorly developed rocky soils
[28]. It occurs on sand, bare rock, alluvium, clay loam or slightly
basic soils often low in organics [5,36,42]. Growth by soil type is as
follows [9]:
gravel: poor organic: poor
sand: fair acidic: fair-poor
sandy loam: good saline: good-poor
loam: good sodic: poor
clay loam: good sodic-saline: poor
clay: fair
dense clay: poor
Creeping juniper commonly grows as an understory species with ponderosa
pine (Pinus ponderosa), limber pine, or Douglas-fir (Pseudotsuga
menziesia) [28]. Other plant associates include blue grama (Bouteloua
gracilis), western wheatgrass (Pascopyrum smithii), needle-and-thread
(Stipa comata), green needlegrass (S. viridula), prairie sandreed
(Calamovilfa longifolia), rough fescue, Idaho fescue (Festuca
idahoensis), shrubby cinquefoil (Potentilla fruticosa), silver
sagebrush, dotted gayfeather (Liatris punctata), and little bluestem
[28,34,41,42].
Growth occurs on a number of topographic positions including the summits
of ridges and on east- or north-facing slopes in the Dakota Badlands
[6,32]. Elevational ranges are as follows [9]:
from: 3,700 to 3,700 feet (1,128-1,128 m) in CO
4,300 to 8,000 feet (1,311-2,438 m) in MT
5,200 to 7,000 feet (1,585-2,134 m) in WY
SUCCESSIONAL STATUS :
Creeping juniper is climax dominant or indicator in a number of habitat
type classification schemes [24]. Its ability to survive on dry, rocky
sites enables it to become part of the topoedaphic climax vegetation in
portions of Montana and the Dakotas [21]. Creeping juniper is
relatively common in climax riverbreak vegetation of the Great Plains
[28].
SEASONAL DEVELOPMENT :
Creeping juniper begins annual growth in early April when the plants
"green up" [28]. The complete process of seed formation and maturation
takes 2 years. Strobiles typically mature and open in early April or
May [28,36]. Cones are usually fertilized during the spring of one
season and mature by August or September of the following year [36].
General phenological development is as follows [28]:
Date Phenological stage
------------------ ------------------------------
April 22 to May 7 pollen shed
June 23 new staminate cones
June 25 first berry formation
mid-July last berry formation
mid- to late July curved penunclate twigs
characteristic of new pistillate
buds begin to form
mid-November all "berries" had turned purple
Flowering dates for creeping juniper vary somewhat according to
geographic location, but flowering usually occurs during May or June
[20,23].
Fruit production peaks in late June to early July. Ripe fruit remains
on the plants for 1 or 2 years [28]. In Montana, annual vegetative
growth is completed by September or early October [28].
FIRE ECOLOGY
SPECIES: Juniperus horizontalis | Creeping Juniper
FIRE ECOLOGY OR ADAPTATIONS :
Creeping juniper is subject to fire-caused mortality or damage, but
limited evidence suggests that this species may be less susceptible to
damage than many other junipers [28]. The low matlike growth form of
creeping juniper results in poor air circulation near the plant, more
limited fuels, and higher relative humidity around the crown [28], all
of which serve to decrease flammability. Creeping juniper can grow on
extremely rocky sites which frequently lack sufficient fuels to carry a
fire.
Reestablishment after fire may occur in a number of ways. In areas
where creeping juniper grows in large mats, parts of the mat may remain
undamaged and survive [28]. In many locations break-up of old mats is
an important means of forming new individuals [28]. This process is
likely to be of at least some importance after fire in certain areas.
Reestablishment after fire may also occur through seed buried on-site in
the soil or brought on-site by water, gravity, or by any of a number of
birds and mammals.
POSTFIRE REGENERATION STRATEGY :
Secondary colonizer - on-site seed
Secondary colonizer - off-site seed
FIRE EFFECTS
SPECIES: Juniperus horizontalis | Creeping Juniper
IMMEDIATE FIRE EFFECT ON PLANT :
Death occurs when the crown is totally consumed by fire [28]. Fires
which consume most of the aboveground foliage usually produce serious
damage to the root system as well [28]. Plants subjected to varying
degrees of partial defoliation often survive, however. Where large
extensive mats occur, fires may not carry across the entire plant, and
survival is fairly common [28]. Smaller plants are believed to be more
susceptible to fire.
Little is known about the specific effects of fire according to fire
intensity or season of burn. Under some circumstances fires of even low
intensity can produce serious damage. Miller [28] observed that
temperatures less than 450 degrees Fahrenheit (267 deg C) are sometimes
sufficient to kill creeping juniper. Creeping junipers survived
temperatures of 109 degrees Fahrenheit (78 deg C) to 450 degrees
Fahrenheit (267 deg C) during a fire in central Montana [28].
DISCUSSION AND QUALIFICATION OF FIRE EFFECT :
NO-ENTRY
PLANT RESPONSE TO FIRE :
Creeping junipers which survived a fire in central Montana generally
produced new leaves and exhibited good growth during the first postfire
growing season [28]. Regrowth during the first growing season ranged
from .005 to .14 ounce (0.14-3.95 g) per plant and averaged .05 ounce
(1.4 g) per plant [28].
Reestablishment is through seed on sites where creeping juniper has been
killed by fire. Germination of juniper seed is often poor [30], and
regeneration is likely to be slow. The seed of most junipers can remain
viable for a relatively long period of time. Some seed can presumably
survive the damaging effects of fire if protected from heat by overlying
layers of soil. Germination of these on-site seeds may occur when
favorable conditions are encountered. Birds and mammals consume
creeping juniper seed and can bring seed onto burned sites from unburned
areas. The length of time required for postfire reestablishment of
creeping juniper has not been documented.
DISCUSSION AND QUALIFICATION OF PLANT RESPONSE :
NO-ENTRY
FIRE MANAGEMENT CONSIDERATIONS :
Fire management potential appears to be somewhat limited because many
creeping juniper sites are much too rocky for fires to carry. Potential
benefits may be slight.
FIRE CASE STUDIES
SPECIES: Juniperus horizontalis | Creeping Juniper
CASE NAME :
Stanford Burn
SEASON/SEVERITY CLASSIFICATION :
Not reported.
STUDY LOCATION :
The burn site was located in the Blacktail Hills of central Montana
approximately 10 miles (16 km) southwest of Stanford.
PREFIRE VEGETATIVE COMMUNITY :
The preburn overstory was made up of scattered Douglas-fir (Pseudotsuga
menziesia) and lodgepole pine (Pinus contorta). Shrubby cinquefoil
(Potentilla fruticosa) dominated the understory, although numerous
grasses and forbs were also present. Creeping juniper grew beneath the
shrubby cinquefoil at an average density of 0.034 plants per meter
square.
TARGET SPECIES PHENOLOGICAL STATE :
Not recorded.
The crown area of individual junipers averaged 0.08 meter square and
height averaged only 3.1 inches (7.8 cm).
SITE DESCRIPTION :
Topography was slightly rolling; elevation averaged 5,890 feet (1,785
m). The area had a history of heavy grazing use.
FIRE DESCRIPTION :
soil moisture beneath plants - average = 49.6%
- range = 45-65%
fuel moisture content - average = 15.0%
- range = 4.0-23.0%
temperature of tagged plants - 78 degrees C (109 degrees F) to
406.9 degrees C (700 degrees F)
- mean 205 degrees C (337.6
degrees F)
FIRE EFFECTS ON TARGET SPECIES :
Approximately 48 percent of creeping juniper canopy coverage was totally
consumed by fire; 41 percent was only partially burned; and 11 percent
was unharmed. Individual crown area burned averaged approximately 85
percent. All creeping junipers with 100 percent foliage damage died,
although many partially damaged plants survived. Of the creeping
junipers tagged prior to the burn, 53 percent were killed when the
foliage was totally consumed; 43 percent were partially burned but
recovered; and 4 percent were totally undamaged by fire. Partially
damaged plants typically showed good recovery. Regrowth during the
first growing season averaged 1.4 grams per plant with a range of 0.14
to 3.95 grams per plant. Temperatures tolerated by surviving plants
ranged from 109 degrees Fahrenheit (78 deg C) to 450 degrees Fahrenheit
(267 deg C). However, several plants were killed by temperatures below
450 degrees Fahrenheit (267 deg C). Pertinent data on tagged creeping
junipers are summarized below:
Plant Crown Height Crown Regrowth
# Area (cm) Area (grams/
m sq. Burned % plant)
1 .08 11.0 100 --
2 .09 7.5 37.5 --
3 .15 8.0 97.5 1.32
4 .01 6.5 100 --
5 .10 3.0 100 --
6 .06 12.0 62.5 1.35
7 .09 11.0 100 --
8 .11 5.0 100 --
9 .16 4.5 100 --
10 .13 8.0 100 --
11 .23 7.0 97.5 3.95
12 .05 8.5 85.0 2.10
13 .04 3.5 97.5 2.00
14 .02 4.0 85.0 0.21
15 .06 9.0 0.0 --
16 .05 6.0 100 --
17 .03 11.0 100 --
18 .10 9.0 100 --
19 .02 7.0 62.5 0.86
20 .04 8.0 62.5 0.37
21 .05 5.0 97.5 0.14
average .08 7.8 85.0 1.40
FIRE MANAGEMENT IMPLICATIONS :
The foliage of creeping juniper must be completely consumed for high
levels of mortality to occur. Many partially burned individuals can
recover relatively rapidly. Results of this study also indicate that
temperature alone does not determine the way in which fire affects
creeping juniper. Other factors also influence fire effects and the
subsequent response of this species.
FIRE CASE STUDIES
SPECIES: Juniperus horizontalis | Creeping Juniper
CASE NAME :
Sun River Burn
SEASON/SEVERITY CLASSIFICATION :
Season not reported/ low severity
STUDY LOCATION :
The study site was located in west-central Montana approximately 22
miles (35 km) west of Augusta on the Sun River Game Range.
PREFIRE VEGETATIVE COMMUNITY :
Preburn vegetation was dominated by creeping juniper, bluebunch
wheatgrass (Pseudoroegneria spicata), rough fescue (Festuca scabrella),
and various forbs. Prairie thermopsis (Thermopsis rhombifolia), silky
lupine (Lupinus sericeus), and milkvetch (Astragalus spp.) were the most
abundant forbs. Creeping juniper grew in large, dense mats at this
site.
TARGET SPECIES PHENOLOGICAL STATE :
Not reported.
SITE DESCRIPTION :
elevation - 4,950 feet (1,500 m)
topography - 5% slope
- northeast exposure
FIRE DESCRIPTION :
The fire was of low intensity.
rate of spread - 2 feet (0.61 m) per minute
flame height - 3 feet (1 m) or less
flame movement - 60 - 90 degrees from horizontal
average fire temperature - 132.3 degrees F (91 degrees C)
average soil moisture - 11%
average fine fuel moisture - 32%
FIRE EFFECTS ON TARGET SPECIES :
An estimated 31 percent of the total canopy coverage of creeping juniper
was consumed by fire; 29 percent was partially burned; and 40 percent
was unharmed. None of the 10 tagged plants was killed by fire.
Regrowth was noted on all tagged leaders during the first growing season
after the burn.
FIRE MANAGEMENT IMPLICATIONS :
Creeping juniper can be killed by fire, although recovery appears likely
where only a portion of the foliage is damaged. Often fire does not
carry well where creeping juniper grows in large, dense mats.
REFERENCES
SPECIES: Juniperus horizontalis | Creeping Juniper
REFERENCES :
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morphological and terpenoid characters in Juniperus scopulorum
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Everett, Richard L., compiler. Proceedings--pinyon-juniper conference;
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[434]
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Index
Related categories for Species: Juniperus horizontalis
| Creeping Juniper
|
 |
