BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Artemisia nova | Black Sagebrush 



GENERAL BOTANICAL CHARACTERISTICS : 
Black sagebrush is a small, spreading, native, aromatic, evergreen
shrub.  Heights usually range from 6 to 18 inches (1.5 to 4.5 dm) but
occasionally reach up to 30 inches (76 cm) on productive sites [41].
Although plants may have an upright habit, typically the branches are
decumbent and arise from a spreading base.  Black sagebrush has a
shallower, more fibrous root system than big sagebrush [37].  As a
result, annual growth depends largely on soil moisture content near the
ground surface.

Distinguishing black sagebrush from low sagebrush (Artemisia arbuscula),
basin big sagebrush (A. tridentata ssp. tridentata), and Wyoming big
sagebrush (A. tridentata ssp. wyomingensis) is often difficult
[7,24,61].  Leaf gland visibility is a morphological character useful in
eliminating taxonomic confusion in the field [36].  Black sagebrush
exhibits tiny, black leaf glands which protrude well beyond the leaf
hairs when viewed with a 10X hand lens [17]; apparently these glands are
inconspicuous in low sagebrush and the three subspecies of big
sagebrush.


RAUNKIAER LIFE FORM : 
   Phanerophyte
   Chamaephyte


REGENERATION PROCESSES : 
Black sagebrush regenerates almost exclusively from seed.  Although
layering has been documented on a road cut in Utah [41], vegetative
reproduction is quite rare.  Numerous, wind-dispersed achenes are
typically shed in October.  Abundant seed is produced annually, but
production is directly related to site characteristics and may be highly
variable from year to year [5].  Seeds require no dormancy breaking
treatment and usually germinate the spring following dispersal.  Bare
mineral soil is needed for successful germination.  Establishment can
occur even on fairly severe sites during good years.  Seeds will remain
viable up to 2 years under proper storage conditions [50].



SITE CHARACTERISTICS : 
Black sagebrush is usually associated with areas with little soil
profile development in desert valleys and on west and south exposures
along the lower slopes of the high desert foothills.  Typical sites
consist of the dry, shallow, gravelly, well-drained soils of alluvial
fans, sills, mountain slopes, and wind-blown ridges.  It occurs most
abundantly at elevations between 4,900 to 7,000 feet (1,470 to 2,100 m)
where annual precipitation ranges between 7 and 18 inches (18 and 46
cm).  Many of the soils supporting black sagebrush are derived from
limestone, particularly along the edges of its range [16].  Shultz [48]
reports this species occurring on shallow lithosols overlying bedrock.
Plants may form dense stands and dominate large areas or may be
associated with a large variety of both grasses and shrubs.

In communities where black and low sagebrush species occur together,
black sagebrush occupies the warmer, more xeric and more calcareous
sites; more mesic sites with deeper soils support basin big sagebrush
(A. tridentata ssp. tridentata) and Wyoming big sagebrush (A.
tridentata ssp. wyomingensis).  With the exception of bud sage (A.
spinescens), black sagebrush is more closely associated with salt desert
habitats than any other Artemisia species.  In the southern Great Basin
stands of black sagebrush are surrounded by salt desert vegetation and
are replaced by shadscale and other salt desert shrubs when sites become
too saline or dry [13,40].

Elevational ranges for several western states are as follows
[2,23,25,28,31,59,62,67]:

    from 2,050 to 9,800 feet (625 to 2,988 m) in CO
         5,000 to 7,000 feet (1,524 to 2,134 m) in ID
         4,000 to 6,600 feet (1,220 to 2,012 m) in MT
         5,904 to 7,544 feet (1,800 to 2,300 m) in NV
         7,200 to 8,200 feet (2,195 to 2,500 m) in NM
         4,000 to 4,000 feet (1,220 to 1,220 m) in OR
         4,592 to 8,987 feet (1,400 to 2,740 m) in UT
         5,000 to 7,000 feet (1,524 to 2,134 m) in WY
  


SUCCESSIONAL STATUS : 
Mature, self-perpetuating stands of black sagebrush are considered to be
indicators of climax conditions.  Seedlings are present during early
seral stages and plants coexist with later arriving species.
Long-established, black sagebrush stands in Nevada have recently
undergone invasion by both Utah juniper (Juniperus osteosperma) and
singleleaf pinyon (Pinus monophylla).  This invasion, which accelerated
around 1921, has been attributed to the combined effects of overgrazing,
fire suppression, and climatic change [13].


SEASONAL DEVELOPMENT : 
The phenology of black sagebrush is similar to low sagebrush (A.
arbuscula) but earlier.  The general pattern in Wyoming is described by
Beetle [5].  Growth is initiated in April, with new leaves being
produced from May throughout most of the summer.  Flower heads first
appear in July, but blooming does not occur until September; they may be
numerous one year and particularly sparse in another.  Seed dispersal
takes place in October.  Late spring leaves and summer leaves persist
through the winter.  Decreases in soil moisture and amounts of
precipitation have a significant impact on the phenology of this
species.  Moisture rapidly infiltrates the coarse, shallow soils of most
sites and is either immediately utilized by the plant or lost through
evaporation [37].

The carbohydrate reserve cycle in black sagebrush shows no pronounced
trend [22].  Generally there is a gradual buildup of root reserves from a
seasonal low in March to floral bud development in August.  Immediately
afterwards a prolonged decline occurs which lasts until September.  Data
is inconsistent on the buildup of reserves through initial flower
opening and fruit set.  Over the winter, approximately one-half of the
root reserves and one-quarter of the crown reserves are lost; twigs
appear to be significant carbohydrate storage areas.

Average dates for the phenological development of black sagebrush on
similar sites in Wyoming have been documented by Kleinman [37] and are
presented below.  He indicates that dates for full bloom and seed
dissemination are somewhat predicatable.

	Growth initiation          May  20
	Full bloom                 September 15
	Seed dissemination         November 5

Related categories for Species: Artemisia nova | Black Sagebrush