BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Vaccinium ovalifolium | Ovalleaf Huckleberry 



GENERAL BOTANICAL CHARACTERISTICS : 
Ovalleaf huckleberry is a stout, erect or spreading, diffusely branched
deciduous shrub [24,26,35,58], which grows from 1.3 to 12 feet (0.4-4 m)
in height [35,47].  Plants often become low and broomy in response to
repeated browsing or under arctic and subarctic conditions where snow
depth limits height [1,8,31].  Height is also reduced under a dense
forest canopy where little light reaches the forest floor; tallest
individuals are generally found under openings in the forest canopy
[33].  Maximum annual growth rates in Alaska reportedly average 12
inches per year (30 cm) [26].

The slender, yellowish-green, glabrous twigs of ovalleaf huckleberry are
conspicuously angled [2,47].  Twigs turn a bright red when exposed to
sunlight [58].  Bark of older branches is grayish or grayish-brown
[29,35].  The thin, alternate leaves are entire or have inconspicuously
serrate margins [14,29,47].  Leaves are oval to elliptical but rounded
at the base and tip [26,35,58].  Leaves are glabrous and generally light
and glaucous below [8,35].

Pink, urn-shaped flowers are borne singly in the axils of leaves
[26,58].  Flowers are generally pollinated by long-tongued bees, such as
bumblebees [29].  The floral morphology of ovalleaf huckleberry has been
examined in detail [53].  Fruit of the ovalleaf huckleberry is a
bluish-purple, dark blue, or black berry with a distinct whitish bloom
[11,29].  The relatively large berries are round, spherical, or slightly
oblate, and seedy [2,26,47,63].  Each berry contains an average of 26
seeds [76], but individual berries may contain up to 150 seeds [26].


RAUNKIAER LIFE FORM : 
   Phanerophyte
   Geophyte


REGENERATION PROCESSES : 
Ovalleaf huckleberry is capable of reproducing vegetatively or through
seed.  Vegetative regeneration appears to be of primary importance in
most western huckleberries (Vaccinium spp.) [44].

Vegetative regeneration:  Ovalleaf huckleberry commonly sprouts from
dormant basal buds after repeated browsing or disturbances which damage
the crown [1,8,31].  Layering, which occurs in the absence of
disturbance, has also been reported [52].  Ovalleaf huckleberry is
rhizomatous and sprouting of these structures is reportedly the primary
means by which colonies expand [26].

Germination:  Seeds of ovalleaf huckleberry have a short dormant period
and exhibit good germination when exposured to 15 days of warm
temperatures followed by 15 days of chilling [11,26].  Properly stored
seeds exhibit good germination under a regime of 14 hours of light at 82
degrees F (28 degrees C) followed by 10 hours of darkness at
temperatures averaging 55 degrees F (13 degrees C).  Fresh seeds also
germinate successfully under these conditions, or when alternately
exposed to temperatures of 71 degrees F (22 degrees C) and 41 degrees F
(5 degrees C) [76].  Huckleberry seedlings first emerge in approximately
1 month and continue to emerge for long periods of time in the absence
of cold stratification [11].  Ovalleaf huckleberry exhibits 50 to 60
percent germination under favorable conditions and up to 93 percent
germination has been observed under optimal laboratory conditions [26].

A minimum of only 2 percent full light is required for germination and
seedlings can develop beneath a forest canopy.  Seeds germinate on a
variety of substrates including decaying wood, humus, moss, and mineral
soil.  Ovalleaf huckleberry typically produces seed annually, but large
amounts of seed are generally produced only in relatively open areas
such as in clearings or at forest margins [26].  Seeds are readily
dispersed by a wide variety of birds and mammals [29].

Seedbanking:  Seedbanking does not appear to be an important
regenerative strategy in ovalleaf huckleberry.  Although seeds can
remain viable for up to 12 years in storage, longevity under natural
conditions is believed to be limited [26].  In montane balsam fir (Abies
balsamea)-paper birch (Betula papyrifera) forests of Quebec, an average
of 6.25 ovalleaf huckleberry seeds per square meter was found within the
top 1.2 inches (3 cm) of soil, but none of the seeds were viable [49].

Seedling morphology and establishment:  Seedling morphology of species
within the section Myrtillus is poorly known.  In the ovalleaf
huckleberry, transition from immature to mature foliage can be either
abrupt or gradual [76].  Seedlings which develop gradually may be easily
confused with seedlings of the closely related Alaska huckleberry [76].

Evidence suggests that ovalleaf huckleberry is a "seedling banker."
Seedlings are capable of surviving in the forest understory until
disturbance creates conditions favorable for development.  Large numbers
of slow-growing seedlings are commonly observed.  Growth is typically
slow beneath a forest canopy, and seedlings often remain in the
cotyledon stage for more than two growing seasons.  Best seedling
survival occurs in open old growth stands and in clearcuts.  Survival is
often poor in immature forests [26].


SITE CHARACTERISTICS : 
Ovalleaf huckleberry grows in cool, moist, submontane to subalpine
forests, on open slopes, and at the edges of bogs, meadows, and swamps
[14,29,32,35,78]. It often occurs on elevated microsites in poorly
drained areas [26].  Ovalleaf huckleberry is commonly absent from major
valley bottoms but does occur on subhydric, colluvial, and morainal
sites in smaller valley bottoms [1,26].

Soil:  Most huckleberries (Vaccinium spp.) require acidic conditions and
can grow on infertile soils which have relatively small amounts of many
essential elements [40].  Ovalleaf huckleberry thrives on soils low in
nitrogen [78].  Ovalleaf huckleberry grows well on well-drained,
nutrient-poor to nutrient-rich soils with a pH of 4.0 to 5.0 [26,51,65].
Soils are derived from a wide variety of parent materials [26].

Climate:  Sites range from dry to moist, but ovalleaf huckleberry is
generally most abundant on moderately moist sites [24,26,61].  Along the
coast of British Columbia, this shrub is associated with a cool
mesothermal climatic regime [78].

Elevation:  Ovalleaf huckleberry grows from sea level to timberline [26]
with elevation ranging from 0 to 5,500 feet (0-1,678 m) [14].  In many
parts of the Northwest, it is particularly common at middle elevations
[47,58].  Elevational range by geographic location is as follows
[58,61]:

              from 0 to 4,500 feet (0-1,364 m) Cascades
                   2,000 to 5,000 feet (606-1,515 m) w OR


SUCCESSIONAL STATUS : 
Ovalleaf huckleberry is shade tolerant and can persist in undisturbed
forests dominated by species such as western hemlock or white spruce
(Picea glauca) [26,72].  It is a common constituent of climax old growth
Douglas-fir-western hemlock, Pacific silver fir, and moist western
hemlock forests of the Pacific Northwest [21,33,60,70], and of western
hemlock-western redcedar-Sitka spruce forests of southeastern Alaska
[75].  Seedlings grow in open, old growth stands or in clearcuts, but
often do poorly in dense, immature forests [26].

Ovalleaf huckleberry commonly appears soon after disturbance in parts of
western Washington [7] and elsewhere.  Sprouts were observed on mudflow
surfaces in scorch and blowdown areas soon after the eruption of Mount
Saint Helens [73,74].  Ovalleaf huckleberry is also one of the first
"forest species" to colonize bog margins in parts of southeastern Alaska
[51].  This shrub often persists on cutover sites throughout its range
and frequently forms a "nearly continuous layer" on newly harvested
sites [24,26,42].

Ovalleaf huckleberry is prevalent in young stands which develop in
avalanche zones in parts of the northwestern Cascades of Washington.
Plants pioneer these sites through layering and sprouting after
aboveground portions of the parent plants are damaged.  The ability to
sprout gives species such as ovalleaf huckleberry a competitive
advantage during early succession in these shrub communities.  Stem
numbers of ovalleaf huckleberry reportedly reach a minimum 60 to 150
years after the initial disturbance.  Advance regeneration subsequently
develops and replaces initial pioneers, producing a subsequent increase
in stem density [52].

Establishment of ovalleaf huckleberry may be slow where parent plants
were absent prior to disturbance.  Clement [71] observed ovalleaf
huckleberry in mature climax forests and in young seral stands on
floodplain gravel bars along the west coat of Vancouver Island.
However, it was absent in early seral stands.  No parent plants were
present prior to disturbance and establishment on the newly exposed
gravel bars proceeded slowly from offsite seed.


SEASONAL DEVELOPMENT : 
In coastal Alaska, bud burst of ovalleaf huckleberry begins in May.
Growth proceeds rapidly, and most vegetative elongation is completed by
mid-June.  Stem diameters continue to increase until mid-July, and leaf
senescence usually occurs by September.  Along the coast of central
British Columbia, leaf senescence can begin in early September, although
some leaves remain on the shrubs until the end of October [26].

Ovalleaf huckleberry flowers before leaves reach one-half of their full
size [35].  Flowering and fruiting by geographic area has been
documented as follows [11,26,49,70]:

     location             flowering           fruiting

     coastal AK           April-May           mid-July-August
     BC coast             ----                late June
     BC                   ----                June-August
     w OR                 May-July            ----
     PQ                   May                 July-August
     Pacific Northwest    May-July            ----    

Related categories for Species: Vaccinium ovalifolium | Ovalleaf Huckleberry