BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES : Amelanchier alnifolia | Saskatoon Serviceberry 


GENERAL BOTANICAL CHARACTERISTICS : 
Saskatoon serviceberry is a native, deciduous shrub or small tree
reaching 3 to 26 feet (1-8 m) at maturity.  Grown alone, the crown is
rounded with spreading to erect branches [51].  Growth form is highly
variable, however; Saskatoon serviceberry often forms thickets, mats, or
grows in clumps [48].  The flowers and fruits are borne in terminal
clusters; the fruits are berrylike pomes.  Each fruit contains 4 to 10
small seeds, some of which are usually infertile.  The seedcoat is
leathery in texture [20].

Underground portions of Saskatoon serviceberry include a massive
root crown, horizontal and vertical rhizomes, and an extensive root
system [19,101].  Bradley [19] reported that the root crown a 9-year-old
individual excavated in Pattee Canyon, Montana, measured 4 inches (10.5
cm) in diameter and 8 inches (20.7 cm) in length.  Rhizomes extending
from the root crown were long and massive; horizontal rhizomes reached at
least 7.8 inches (20 cm) and vertical rhizomes extended at least 30.4
inches (78 cm).  Roots of a 12-inch-tall (30 cm) Saskatoon serviceberry
excavated in Idaho extended 32 inches (80 cm) below ground [105].

Saskatoon serviceberry is relatively short lived.  Lonner (cited in [48])
reported that in western Montana, 61 percent of 470 plants were between
6 and 20 years old (mean = 17.9).  The oldest individual was 85.


RAUNKIAER LIFE FORM : 
   Phanerophyte
   Geophyte


REGENERATION PROCESSES : 
Saskatoon serviceberry reproduces from seed, by sprouting from the
root crown and/or rhizomes, and by layering [19,20,35,95].

Vegetative reproduction by sprouting is most common.  On four western
Montana sites, Hemmer [48] found that over 90 percent of new stems
sampled were sprouts from previously existing plants.  On two burns, all
sprouts originated from root crowns.  On two clearcuts, most sprouts
came from rhizomes.

Regeneration from seed is apparently rare, being limited by moisture,
low spring temperature, and/or disease [16,20].  In several locations in
western Montana, Hemmer [48] found that sprouting from top-killed plants
was common, but only one site, on the Yaak River, had Saskatoon
serviceberry seedlings.  Flowers are produced almost every year, but
because of drought, spring frost, and/or juniper rust (Gymnosporangium
spp.), good seed crops may be produced only every 3 to 5 years [16,48].
Even under good conditions, most fruits contain some unviable seed [51].
Seed is dispersed by frugivorous birds and mammals [20,90].  It is
dormant and requires overwinter stratification.  In the laboratory,
seventy percent germination was obtained from fresh seed stratified for
180 days and then given day/night temperatures of 86/68 degrees
Fahrenheit (30/19 deg C) for a month [20].  Good seed may remain viable
for years.  Seed stored in an unheated warehouse in Utah showed 91, 80,
91, 85, and 84 percent germination after 2, 3, 5, 7, and 10 years of
storage, respectively [92].


SITE CHARACTERISTICS : 
Saskatoon serviceberry grows on mountain slopes, hillsides, prairies,
and riparian zones [31].  Pfister and others [81] reported Saskatoon
serviceberry in every habitat type in Montana except timberline and
moist subalpine fir (Abies lasiocarpa) types.  Atzet and McCrimmon [12]
noted that in the Cascade Range of Oregon, white fir-lodgepole pine (A.
concolor-Pinus contorta)/Saskatoon serviceberry associations tend to
occur in frost pockets.

Saskatoon serviceberry grows on relatively infertile soils but also
occurs on nutrient-rich substrates [91].  Soils are well-drained and
typically mesic, although moisture regime varies from moist to
seasonally dry [48,57,91].  Saskatoon serviceberry apparently does not
tolerate prolonged drought.  In Montana it does not occur on sites with
less than 14 inches (355 mm) of annual precipitation [48].

Saskatoon serviceberry occurs from near sea level to timberline [48].
Elevational range by state is:

California     160 to  8,530 feet    (50-2,600 m) [51] 
Colorado     5,000 to 10,000 feet (1,500-3,000 m) [46] 
Utah         4,000 to  9,500 feet (1,220-2,900 m) [103]


SUCCESSIONAL STATUS : 
Saskatoon serviceberry grows in open sun to moderate shade.  It is
intolerant of deep shade, and declines with canopy closure [3,9,43].  It
rarely establishes from seed in early stages of primary succession
[26,37].  Eleven years after the 1980 eruption of Mount St. Helens in
Washington, mature Saskatoon serviceberry plants occurred only on
refugia plots on the volcano slope.  Neither seedlings nor mature plants
occurred on sites of volcanic deposition [26].

Riparian succession:  In riparian areas in southeastern British
Columbia, Saskatoon serviceberry occurred mostly in stabilized black
cottonwood (Populus deltoides) galleries on the upper floodplain.  It
did not occur on low gravel bars subject to frequent flooding [37].  A
study on the Yellowstone River of Montana had similar findings.  The
successional sere there is:  plains black cottonwood (P. deltoides var.
monilifera) seedling; plains black cottonwood-Sandbar willow (Salix
interior) sapling; pole plains black cottonwood; mature plains black
cottonwood; shrub thicket; and grass.  Saskatoon serviceberry was most
common in mature plains black cottonwood stands and in shrub thickets.
It was sparse on grassland and absent in seres with young plains black
cottonwood [17].

Secondary succession:  Saskatoon serviceberry is common after
disturbances such as fire, logging, or insect outbreak [6,9,95].
Saskatoon serviceberry increased significantly (P < 0.1) after a
stand-destroying mountain pine beetle attack in lodgepole pine (Pinus
contorta) in Glacier National Park, Montana.  Maximum foliage production
of Saskatoon serviceberry occurred 2 years after the overstory was
killed [6].


SEASONAL DEVELOPMENT : 
Saskatoon serviceberry flowers early in the growing season [20].  It is
usually the first shrub to bloom in spring.  Anthesis is a mass event
lasting about 2 weeks [90].  Leaves emerge during or just after
flowering [20].  Fruits ripen 1 to 2 months later, from July to
September, depending upon location [101].  General fruiting and
flowering periods are given below.

               flowers     fruits
               _________   ______
Alaska          June        July [102]
North Dakota    May          --  [23]
Ontario         June        July and August [88]
Saskatchewan    May-July     --  [109]

A more detailed calendar of phenological development of Saskatoon
serviceberry east of the Continental Divide of Montana and in
Yellowstone National Park, Wyoming, is presented below [85].

      Event                       Dates
___________________     _________________________
leaf buds open          April 12- May 29
flowering starts        April 15 - June 18
flowering stops         May 15 - July 3
leaves fully expanded   May 15 - July 13
fruits ripe             July 10 - August 19
seed fall starts        July 11 - September 15        
leaves change color     July 23 - September 25
leaf fall begins        August 13 - October 1
leaves fallen           September 5 - October 21

Related categories for SPECIES : Amelanchier alnifolia | Saskatoon Serviceberry