BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Bromus vulgaris | Columbia Brome 



GENERAL BOTANICAL CHARACTERISTICS : 
Columbia brome is a native perennial bunchgrass [8,18,41].  Culms are
slender, hollow, and 18 to 47 inches [45-120 cm) tall [20,21,36].  Leaf
blades are flat [18].  The inflorescence is an open panicle [20];
branches are slender and spreading to drooping [22].  Spikelets are
five- to seven-flowered.  Lemma are awned [20,32].  The fruit is a
caryopsis [18].


RAUNKIAER LIFE FORM : 
   Hemicryptophyte


REGENERATION PROCESSES : 
Columbia brome sprouts from perennating buds at the bases of culms [22].
It also reproduces by seed [36].

Columbia brome occurs in soil seedbanks but may not be plentiful.  In a
seedbank study in grand fir/pachistima habitat in the Blue Mountains of
northeastern Oregon, Columbia brome occurred in two of the three mixed
conifer stands investigated.  Forest floor core samples were taken to
test for seed germination.  Soil from a stand in which Columbia brome
occurred with 0.6 percent cover and 26 percent frequency produced no
Columbia brome seedlings from any soil layer.  Soil from a stand in
which Columbia brome occurred with cover of 5.1 percent and frequency of
54 percent produced two Columbia brome seedlings from the litter and
humus layer and none from mineral soil.  Soil samples from this stand
produced 338 seedlings of 30 species [40].


SITE CHARACTERISTICS : 
Columbia brome is found on open or forested sites from sea level to
lower subalpine mountain habitats [18,27] in moist to dry conditions
[8,42].  It grows in shaded or open woods, on moist or dry streambanks
[22], in seepage areas [2], rocky ravines [32], and on dry rocky slopes
[22].

Columbia brome grows in soils of many types.

In northern Idaho near the St. Joe River, Columbia brome occurs in soils
with volcanic ash surface and sandy loam subsurface [19].  In Latah
County, Idaho, it grows in deep, moderately well-drained loessal soil
[29].  In the Coast Ranges of west-central Oregon, Columbia brome is
found on soils of clay and silty clay loam; available moisture is high
[1].  In the Crater Lake area of Oregon it occurs on deep, well-drained
soils of volcanic origin with loam surface layers and clayey loam
subsoils [30].  In Linn County, Oregon, Columbia brome is found on gray
basalt soils from lava flows [35].  In the Blue Mountains of
northeastern Oregon occurs on soils which include volcanic ash and are
at least 53 inches (135 cm) deep [40].  Columbia brome in southwestern
British Columbia is found on acidic loamy sand to sandy loam.  The soil
nutrient regime is rich to very rich [25].

Columbia brome generally occurs in climates with cool, wet winters and
warm, dry summers [30].  Snowpack often insulates it from extreme cold
[35]. 

Columbia brome presence in seral shrub communities in northern Idaho was
evaluated for correlation with several environmental variables.
Frequency increased with elevation, from 16 percent at the lowest site
measured (3,000 feet [914 m]) to 38 percent at the highest site (4,600
feet [1,402 m]).  There was no significant correlation between frequency
and north or south exposure [31].  On the other hand Columbia brome was
an indicator of north slopes and increasing elevation in the Blue
Mountains of eastern Oregon and southeastern Washington [17].

Columbia brome is reported at the following elevations:

                           Feet           Meters

     California            0-6,234         0-1,900    [7,20,32]
     Idaho             2,500-5,500       762-1,675    [3,15,19,29,38]
     Montana           4,700-6,000     1,433-1,829    [8,44]
     Oregon                0-6,500         0-1,981    [1,17,30,40,41]
     Utah                  6,500           1,981      [8]
     Washington        1,815-6,140       550-1,870    [11]
     Wyoming               8,000           2,438      [8]
     British Columbia        689             210      [25]


SUCCESSIONAL STATUS : 
Facultative Seral Species

Columbia brome occurs in open or shaded habitats [27] in many
successional stages.  It is found on clearcuts [3,19], in seral
shrubfields [19,31], and in mature undisturbed shaded forests
[11,14,30,37].

Columbia brome occurs on seasonally disturbed gravel bars in the
Flathead River, northwestern Montana [28].

Columbia brome occurs with red alder (Alnus rubra) in the Alsea River
drainage of the Oregon Coast Ranges.  Red alder is a pioneer species
whose establishment within the study area requires disturbance [6].

Columbia brome occurred in grand fir/wild ginger (Asarum caudatum)
habitat in northern Idaho with 20 percent cover 0 to 30 years after a
low soil displacement clearcut which was seeded with grass.  Some seed
used on the site probably contained Columbia brome [47].  Columbia brome
occurred with 1 to 3 percent cover in other clearcuts of low and high
soil displacement where grasses were not seeded [15,24].

Columbia brome in seral shrub communities in northern Idaho reached
highest frequencies under conditions of partial shading [31].

Columbia brome in grand fir/pachistima habitat in the Clearwater
Mountains of north-central Idaho was studied for possible correlation
between presence and overstory structure.  Graminoid production was not
significantly correlated with any of the measured overstory parameters.
In undisturbed forest, Columbia brome had a constancy of 90 percent,
canopy coverage of 7 percent, and frequency of 25 percent; it
contributed more to understory production than any other graminoid.
Soil nutrient status was probably the major factor determining growth
response of Columbia brome under these shaded conditions [33].


SEASONAL DEVELOPMENT : 
Columbia brome phenology at Nash Crater lava flows in Linn County,
Oregon, was recorded from the middle of May to the last of September
1949.  Columbia brome began flowering the second week of June and
completed flowering the last week of June, when fruiting began; fruiting
continued through the first week of September [35].

In California, Columbia brome flowers and fruits from May to August
[32].  In western Oregon and southwestern Washington, it flowers and
fruits from June through August [18,41].

Related categories for Species: Bromus vulgaris | Columbia Brome