Ceanothus velutinus Dougl.

More info for the terms: density, fire use, forest, litter, moderate-severity fire, prescribed fire, restoration, scarification, seed, severity, shrub

Density: Following a prescribed fire in a quaking aspen/mixed conifer stand in Idaho, the
density of snowbrush ceanothus stems was about half of the preburn density, and biomass was
considerably less than preburn levels. Some mortality to snowbrush ceanothus and
the long time needed to grow clumps of large diameter stems, like those that existed
before fire, accounts for its slow recovery [43].

Fire severity: Though some authors
report that snowbrush ceanothus establishment from seed is greatest following
severe burns and lowest following low-severity burns [81,101],
Gratkowksi [109] found that snowbrush ceanothus seedlings were far more
abundant on "lightly" burned sites than on "severely" burned sites. Weatherspoon
[281] found that greater snowbrush ceanothus
seedling development occurred in areas of moderate burn depth or severity than
in either unburned areas or areas of high burn depth. Moderate-severity fire
removes the litter layer, sufficiently scarifying and leaving most snowbrush
ceanothus seeds close enough to the postfire surface to permit emergence. Severe
fire, on the other hand, results in lethal temperatures at a soil depth
where most of the seed bank is located. Though creating a zone of scarification
below that depth, much of the snowbrush ceanothus seed bank is consumed by the
fire, leaving fewer seeds to germinate [281]. Following a prescribed fire in a white fir forest in
California that burned to a depth of 4 inches (10 cm) in the soil, 94% of snowbrush
ceanothus seeds were killed, with no viable seeds remaining above the
1.5-inch (4-cm)
depth [282].

For further information on prescribed fire use and postfire responses of multiple plant species in plant communities with snowbrush ceanothus, see the following Fire Studies:

• Lyon's Research Paper,
  Initial vegetal development following prescribed burning of Douglas-fir in south-central Idaho
• Martin's Research Paper,
  Shrub control by burning before timber harvest (ponderosa pine and mixed-conifer communties on the Pringle Falls Experimental Forest, Oregon)
• Metlen's Research Project Summary,
  Vegetation response to restoration treatments in ponderosa pine-Douglas-fir forests of western Montana

snowbrush ceanothus

shiny-leaf ceanothus

tobacco brush

More info for the term: shrub

Cover value of snowbrush ceanothus for wildlife has been rated as follows [80]:

  Utah Colorado Wyoming Montana
Elk fair --- fair poor
Mule deer fair --- fair  poor
White-tailed deer --- --- fair poor
Pronghorn poor --- poor ---
Upland game birds fair good good fair
Waterfowl poor --- poor ---
Nongame birds good fair good fair
Small mammals good fair good fair



Snowbrush ceanothus shrub layers provide nesting sites for small birds [244].

More info for the terms: fruit, natural, seed, shrub

Snowbrush ceanothus is a native [37,38] evergreen [70,72,127,129,197,284,285] shrub.
It generally grows 2 to 9 feet tall (0.5-2.7 m) [37,64,70,72,127,135,154,197,242,285],
though it may also reach heights of 12 to 13 feet (4 m) [77,240,271]. Plants are
freely
branching [70] or spreading [121,154,271,285] with several stems growing from the base
[64]. The growth form is ascending-erect [127,252], forming a dense, round-topped bush
[64,121,127,197,271,285]. Snowbrush ceanothus has a single large taproot and a
deep, spreading root system [240]. The roots extend to depths of 6 to 8
feet (2-2.5 m) and extend laterally past the crown of the plant [63,71]. Root nodules are
nitrogen fixing
[38,72,73,121,154,197] and are
formed by actinomycetes [38,73].

The leaves are alternate [70,285], 1 to 3 inches long
[37,70,127,129,197,284,285], and 0.5 to 2 inches (1.5-5
cm) wide [70,82]. The inflorescence of snowbrush ceanothus is less than
5 inches (12 cm) long [70,127], and branched with many flowers [70,154,197]. The
inflorescence is borne on axillary and terminal
peduncles [70]. Fruit is shallowly 3-lobed [37,70,109,127,197,285],
0.12 to 0.16 inch (3-4 mm) thick [70,127,285], 0.27 inch (6 mm) across [197], and
sticky [70,127]. Each lobe contains a single seed [197]. Seeds are about 0.1
inch (2.8 mm) long, 0.1 inch (2.3 mm) wide, and 0.08 inch (2.0 mm) thick [109].

Snowbrush ceanothus forms large, dense colonies [70,121,240]. Thickets
may be up to 33 feet (10 m) wide and are often dense and impenetrable [121,261]. In general, the number of snowbrush ceanothus plants in an
area decreases with age [303]. Though stands of snowbrush ceanothus
may begin to deteriorate after 15 years [175,303],
the natural life span of snowbrush ceanothus is greater than 25 years [94,175], and 50-year-old plants have been observed
[59,63].

More info for the terms: cover, presence

Snowbrush ceanothus occurs from British Columbia and Alberta south to
California, Utah, and Colorado [70,127,142,197,285] and as far east as
South Dakota [142,197,285]. The PLANTS
database provides a distributional map of snowbrush ceanothus. Distribution of snowbrush ceanothus may be influenced locally by frost
patterns and the presence of insulating snow cover during the winter [116,197].

Ceanothus velutinus var. hookeri grows on the west side of
the Cascade Range from northern California to British Columbia [129]. Ceanothus
velutinus var. velutinus is widespread and occurs form British Columbia through
California and Nevada east of the Cascades to South Dakota and Colorado
[63,129]. 

More info for the terms: fire regime, forest, fuel, fuel loading, root crown, scarification, seed, shrub

Fuels Contribution: Snowbrush ceanothus burns "quite hot" [2]. The foliage contains volatile oils
that may contribute to fire
hazard [284]. Percentage of solvent extractives
(waxes, oils, terpenes, and fats) by dry weight found in snowbrush ceanothus fuel is
as follows [64]:

Foliage
Woody fuel (diameter in inches)
  < 0.25 0.26-0.50 0.51-1.00 > 1.00
18.3 6.0 4.2 3.3 2.6

The foliage extractive heating value for snowbrush ceanothus
has been reported at 11,942 Btu per pound [64]. Richards [222]
found that the potential rate of spread through snowbrush ceanothus can be
expected to increase as the growing season progresses from June 20 to September
10. This expectation is based on an increase in caloric content (from 1,400-2,400 calories/gram) and a decrease in the water content (from 68% to 53%) of
green vegetation.

The
following table presents information on snowbrush ceanothus fuel loading; the
data is based on single-species plots and presented by fuel category [64]:

 
Load
Foliage
Woody fuel (diameter in inches)
< 0.25 0.26-0.50 0.51-1.00 > 1.00
Tons/acre
Percent
Plot 1 40.91 5.5 24.4 21.1 49.0 --
Plot 2 38.51 3.1 18.9 30.5 36.5 11.8
Plot 3 22.45 6.0 25.3 33.7 35.0 --

Fire Adaptations: Snowbrush
ceanothus has dormant, ground-stored seed that requires heat treatment to
germinate [109,148,168,236]. Snowbrush ceanothus is promoted by fire,
regenerating from seed stimulated by fire [63,143,163,201,228]. Where its seeds are present in
the soil, snowbrush ceanothus may dominate early seral growth following a
"medium or hot" fire [12]. Snowbrush ceanothus also sprouts vigorously
from the root crown after fire
[201,228,236]. Resprouting may be an adaptation to recurring
fires, allowing for rapid growth and recovery [201]. Fire creates conditions more favorable
for snowbrush ceanothus growth by removing the overstory [109]. Snowbrush
ceanothus shows a marked increase in burned forest areas
due to heat scarification of seed, sprouting, and increased light [109,119]. When conifers overtop the shrubfields, snowbrush
ceanothus may die out because of reduced light intensities in the forest
understory [119,120].


As a nitrogen fixer, snowbrush ceanothus plays an
important role in nitrogen reaccumulation following fire [143].

Early
seral shrub layers dominated by snowbrush ceanothus form in grand fir/big
huckleberry [242], grand fir/Rocky Mountain maple [245,247],
Douglas-fir/ninebark
[244], Douglas-fir/pinegrass [246,248], Douglas-fir/white spirea [249], and Douglas-fir/Rocky Mountain maple [244] habitat types in
response to fire. Dry weather patterns following canopy removal and repeated
severe fires are likely to produce persistent seral shrubfields [239,304]. In the northern
Rocky Mountains, pure stands of snowbrush ceanothus may form on the
south-facing slopes of these shrubfields [239].

FIRE REGIMES: Fire
return intervals for plant communities and ecosystems in which snowbrush ceanothus occurs
are listed below. Find further fire regime information for the plant communities in which this
species may occur by entering the species name in the FEIS home page under "Find FIRE REGIMES".

Community or Ecosystem Dominant Species Fire Return Interval Range (years)
silver fir-Douglas-fir Abies amabilis-Pseudotsuga menziesii var. menziesii > 200 
grand fir Abies grandis 35-200 [9]
California chaparral Adenostoma and/or Arctostaphylos spp.
sagebrush steppe Artemisia tridentata/Pseudoroegneria spicata 20-70 [211]
basin big sagebrush Artemisia tridentata var. tridentata 12-43 [230]
mountain big sagebrush Artemisia tridentata var. vaseyana 15-40 [10,46,188]
Wyoming big sagebrush Artemisia tridentata var. wyomingensis 10-70 (40**) [274,294]
California montane chaparral Ceanothus and/or Arctostaphylos spp. 50-100 [211]
curlleaf mountain-mahogany* Cercocarpus ledifolius 13-1000 [13,233]
mountain-mahogany-Gambel oak scrub Cercocarpus ledifolius-Quercus gambelii
western juniper Juniperus occidentalis 20-70 
Rocky Mountain juniper Juniperus scopulorum
western larch Larix occidentalis 25-100
Engelmann spruce-subalpine fir Picea engelmannii-Abies lasiocarpa 35 to > 200 
blue spruce* Picea pungens 35-200 
pinyon-juniper Pinus-Juniperus spp. 211]
Rocky Mountain lodgepole pine* Pinus contorta var. latifolia 25-300+ [8,9,227]
Sierra lodgepole pine* Pinus contorta var. murrayana 35-200 [9]
Colorado pinyon Pinus edulis 10-49 [211]
Jeffrey pine Pinus jeffreyi 5-30 
western white pine* Pinus monticola 50-200 
Pacific ponderosa pine* Pinus ponderosa var. ponderosa 1-47
interior ponderosa pine* Pinus ponderosa var. scopulorum 2-10 [9]
quaking aspen (west of the Great Plains) Populus tremuloides 7-120 [9,112,183]
Rocky Mountain Douglas-fir* Pseudotsuga menziesii var. glauca 25-100 [9]
coastal Douglas-fir* Pseudotsuga menziesii var. menziesii 40-240 [9,196,224]
California mixed evergreen Pseudotsuga menziesii var. m.-Lithocarpus densiflorus-Arbutus
menziesii
California oakwoods Quercus spp.
canyon live oak Quercus chrysolepis
blue oak-foothills pine Quercus douglasii-Pinus sabiniana
Oregon white oak Quercus garryana 9]
California black oak Quercus kelloggii 5-30 [211] 
redwood Sequoia sempervirens 5-200 [9,89,260]
western redcedar-western hemlock Thuja plicata-Tsuga heterophylla > 200 
western hemlock-Sitka spruce Tsuga heterophylla-Picea sitchensis > 200 
mountain hemlock* Tsuga mertensiana 35 to > 200 [9]


*fire return interval varies widely; trends in variation are noted in the species summary

**mean

More info for the terms: cover, density, forest, frequency, habitat type, prescribed fire, seed, severity

Season of Burning: In general, low severity spring burns can increase snowbrush ceanothus cover
quickly through regrowth from root crowns. Spring burning of seral
brushfields in the Douglas-fir/ninebark habitat type in Montana resulted in snowbrush
ceanothus exceeding its prefire coverage in the 1st postfire growing season, and
its
percent coverage nearly doubled during the 3rd postfire growing season [206].
While potentially killing a large number of mature snowbrush ceanothus plants
[207], severe summer and fall burns generally stimulate germination of
ground-stored seed to produce young plants, thus providing a long-term increase
in snowbrush ceanothus [206]. Snowbrush ceanothus seedling establishment
is usually enhanced by fall burns. A high-severity fall burn is more likely to
produce a dense stand of snowbrush ceanothus than a "cooler" spring burn [217], and spring burns produce fewer
sprouts
[295]. Prescribed fires must burn hot enough to stimulate seed germination, otherwise
snowbrush ceanothus is unlikely to increase on a site [264].


Slash Disposal: Snowbrush ceanothus commonly establishes on sites that have been broadcast
burned following harvesting activities,
and can establish by the 1st year after disturbance [54,109,223,300].
Burned sites are
more likely to have substantial snowbrush ceanothus in the successional
community than unburned sites [199].
In the western redcedar-western hemlock zone of northern Idaho, the frequency, crown cover, and
relative importance of snowbrush ceanothus were much greater in broadcast burned
areas than in either undisturbed or logged, unburned areas [198]. Maximum cover was attained 3 to 5 years after timber
harvest associated with subsequent slash burns in western hemlock forests of
north-central Idaho. Where timber harvest was not followed by
postharvest burns, cover increased much more slowly, and maximum values were not
reached until 15 to 25 years after disturbance [159]. Snowbrush
ceanothus also responded to broadcast burning following harvest in ponderosa
pine stands in Mt. Hood National Forest, Oregon [228]. Broadcast burning results in a greater number of snowbrush ceanothus seedlings
than piling and burning slash [109], though the occurrence of
snowbrush ceanothus also increases on sites that have been slash-burned rather
than not burned [251].


Snowbrush ceanothus may dominate early seral stages
following clearcut and severe broadcast burning activities in grand fir
and Douglas-fir habitat types [101,110,250,300], as well as sites in the
western hemlock zone that have been logged and lightly or heavily burned [117].
Seven years following a prescribed fire in a Douglas-fir forest in Idaho, snowbrush ceanothus density increased from 0.1 to 56.4 per 1,000 square feet, and percent canopy cover
increased from 0.02 to 10% [165]. In another study, however, snowbrush
ceanothus cover on clearcut, broadcast burned Douglas-fir sites in Oregon did not increase
substantially until 15 years after treatment, with cover values dropping again by
postfire year 20 [232].



Fire Severity: The duration and magnitude of snowbrush ceanothus dominance
generally increase with the
severity of disturbance [117,155]. Following the
Waterfalls Canyon Fire, a severe burn in Wyoming, snowbrush ceanothus remained
abundant for more than 40 postfire years [18]. Fourteen to 23 years following
a clearcut and "hot" broadcast burn treatment in a Douglas-fir forest,
percent cover of snowbrush ceanothus ranged from 4 to 85%, increasing from the
original 0% [12]. In a study of clearcut and broadcast
burned grand fir sites, snowbrush ceanothus disappeared by 23 years after
treatment [300]. Lafferty [155] found that the highest canopy
cover increase of snowbrush ceanothus on sites in western Montana occurred on
severely burned (vs. lightly burned), south-facing sites. In the western
redcedar-western hemlock zone of
northern Idaho, snowbrush ceanothus occurred more frequently and with greater
percent cover on sites that had been burned than on sites that were either
undisturbed or logged and not burned. Sites that were broadcast burned had more
snowbrush ceanothus than sites that were slash-piled and burned, and multiple broadcast
burns resulted in the highest snowbrush ceanothus values [199]. In a Douglas-fir forest
on the H. J. Andrews Experimental Forest,
percent cover of snowbrush ceanothus increased 2 years after clearcutting with
no burning, clearcutting with light burning, and clearcutting with severe
burning. The greatest increase in percent cover followed the light burn
treatment [83]. On another Douglas-fir site in Oregon,
snowbrush ceanothus percent cover steadily increased for 5 years following slash
burning in clearcuts, from 0.3% to 7.5%. After logging but prior to burning, no
increase of snowbrush ceanothus percent cover was observed [84].
Morris [194,195] found that snowbrush ceanothus grew on harvested sites
following slash burning, but was much more scarce on unburned sites in
Douglas-fir communities of Oregon.


Wildlife Implications: Dense canopies of snowbrush ceanothus generally result from severe burns, and
will deter both livestock and erosion; light canopies generated by a
low-severity burn can provide shelter for Douglas-fir seedlings
[242,244,246,247,248].
In western Montana, long-term propagation of snowbrush ceanothus for elk winter
range may be best accomplished through fall burning, both to stimulate seed
germination and reduce impacts of concentrated browsing [169]. However,
Noste [205] found that survival of snowbrush ceanothus was higher on
spring-burned that on fall-burned sites (100% survival versus 40%).



Nutrient Content: During the 1st growing season following prescribed burning of seral shrubfields
(Douglas-fir climax) in British Columbia,
nitrogen concentration and phosphorus concentration of snowbrush ceanothus
leaves increased, though the levels returned to preburn concentrations by the
2nd growing season. Copper concentrations in snowbrush ceanothus leaves and
stems decreased following burning [78]. The following table
summarizes snowbrush ceanothus plant information and nitrogen accretion of a
snowbrush ceanothus stand developing on a Douglas-fir clearcut and slash-burn
site in Oregon [298]:


Postburn year
Density plants/ha
Nodulation (% of roots)
Cover (%)
Snowbrush ceanothus biomass
N accretion (kg/ha)
Dry weight (kg/ha) N concentration (%)
1 142,100 0 trace 99 2.00 2.0
2 149,000 0 trace 655 1.37 9.0
3 96,100 7 17 2,789 1.37 38.2
4 70,100 25 17 9,548 1.27 121.3
5 61,700 42 25 23,084 1.05 243.4
7 61,700 71 50 30,992 1.16 359.5
10 36,400 92 58 54,287 0.66 358.3
15 35,500 100 70 62,100 0.48 298.8


As snowbrush ceanothus biomass increased with age, nitrogen
concentration decreased due to the higher proportion of woody material relative
to leaf tissue. Net accretion of nitrogen by snowbrush ceanothus fixation was 1,110 pounds per acre
(1,261 kg/ha) over the 15 years of the study [298].

Root Nodulation: Nodulation of snowbrush ceanothus seedlings that establish following fire may
be a function of the overstory stand age before disturbance. Wollum and others [289]
found that, in stands that were harvested and burned before the stand age reached
100 years, snowbrush ceanothus nodulation was substantially higher than in
stands over 100 years old. Snowbrush ceanothus generally disappears from stands
as the canopy closes, and the authors speculate that in the absence of a host,
the actinomycetes responsible for nodulation in snowbrush ceanothus also decline
on the site [289].

More info on this topic.

More info for the terms: geophyte, phanerophyte

RAUNKIAER [220] LIFE FORM:




Phanerophyte

Geophyte

More info for the terms: cover, frequency, mesic

Thickets of snowbrush ceanothus often occupy open rocky hillsides and partially
shaded forests [37]. Plants are often found on moderately dry to
moderately moist mountain slopes [70,130,132,136,154,197,209,240] and on steep
canyon slopes [284]. Though found on all aspects [198,207,217,240,300], snowbrush ceanothus may be more likely to occur on south aspects [132,136,154,199,266], followed by west
[132,136,154] and east slopes [207,217]. In the western redcedar-western hemlock zone of northern Idaho,
frequency and percent
cover of snowbrush ceanothus were significantly greater (p<0.01) on south
aspects than on north aspects [198]. Though snowbrush ceanothus occurs on moist as well
as relatively dry sites, it is more likely to dominate the
vegetation on mesic sites [135,144,238].

Elevation: Snowbrush ceanothus has a wide elevational
distribution [240], extending from near sea level to high mountains [271]. It
generally occurs at higher elevations on south-facing slopes than on
north-facing slopes [5,14]. Elevation ranges for different areas of snowbrush
ceanothus distribution are as follows:


Location Elevation range References
Oregon, Washington 1,500 to 7,000 feet (450-2,130 m) [26,103,104,124,130,262,278,301]
Wyoming, Montana, Idaho 3,800 to 9,500 feet (1,150-3,000 m) [51,80,208,300]
California
up to 9,800 feet (3,000 m)  [64,127]
Great Basin region 3,500 to 10,000+ feet  (1,050-3,050 m) [27,197]
Utah 4,900 to 13,000 feet (1,490-3,960 m) [70,80,209,285]
Colorado 6,000 to 10,000 feet (1,830-3,050 m) [80]

Climate: In the Pacific Northwest, winters are moderately cold and relatively wet, with
precipitation generally occurring from November to May. Annual
precipitation at sites with snowbrush ceanothus in this region has been reported
at 18 to 23 inches (460-580 mm) [26,124]. Summers are warm and dry [26]. In California,
annual precipitation may range from 40 to 60 inches (1020-1520 mm) [104,176]. In
Montana and Idaho, annual precipitation ranges from 27 to 45 inches (690-1140
mm) [51,158]. In
Utah, the moisture requirement of snowbrush ceanothus is 16 to 20 inches
(410-510 mm) [209].


In Idaho, the growing season lasts from 70 to 90 days [51]. 
Snowbrush ceanothus has good winter hardiness, though it may be subject to
winter dieback on exposed sites [121]. It is damaged by low
temperatures if not protected by snow cover [162,252,261].
Conversely, if snowbrush ceanothus crowns are not covered by snow, they are
susceptible to winterkill if a relatively warm period (reducing winter
hardiness) is followed by a sudden severe drop in temperature [252]. 


Soils: Growth of snowbrush ceanothus is fair on
gravelly, sandy, and clay loam soils and poor on dense clays [80]. It grows well on sandy loams, loams, and clay loams [80,130,176,208]
and on poorly developed, loose or unstable soils [14,26]. Soil
depths range from shallow soils with numerous rock outcrops to deposits of
unconsolidated material many feet deep [26]. Although snowbrush
ceanothus grows in almost any soil, it grows best in medium- to coarse-textured,
well-drained soils 20 to 60+ inches (51-152+ cm) deep [37,130,198,208,240,261].
Soil nutrient content is generally low [121,162]. A soil pH of 5.5 to 7.0
is often found on snowbrush ceanothus sites [37,261]. Snowbrush
ceanothus has medium tolerance for acid soils [121,271], and neutral to
moderately alkaline soils can also produce good growth [37]. Snowbrush ceanothus is moderately
drought tolerant [121,261].

More info on this topic.

This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

More info for the term: cover

SAF COVER TYPES [86]:




205 Mountain hemlock

206 Engelmann spruce-subalpine fir

207 Red fir

210 Interior Douglas-fir

211 White fir

212 Western larch

213 Grand fir

215 Western white pine

216 Blue spruce

217 Aspen

218 Lodgepole pine

219 Limber pine

220 Rocky Mountain juniper

224 Western hemlock

225 Western hemlock-Sitka spruce

226 Coastal true fir-hemlock

227 Western redcedar-western hemlock

228 Western redcedar

229 Pacific Douglas-fir

230 Douglas-fir-western hemlock

231 Port-Orford-cedar

232 Redwood

233 Oregon white oak

234 Douglas-fir-tanoak-Pacific madrone

237 Interior ponderosa pine

238 Western juniper

239 Pinyon-juniper

243 Sierra Nevada mixed conifer

244 Pacific ponderosa pine-Douglas-fir

245 Pacific ponderosa pine

246 California black oak

247 Jeffrey pine

249 Canyon live oak

250 Blue oak-foothills pine

256 California mixed subalpine

More info on this topic.

This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

More info for the term: shrub

ECOSYSTEMS [98]:




FRES20 Douglas-fir

FRES21 Ponderosa pine

FRES22 Western white pine

FRES23 Fir-spruce

FRES24 Hemlock-Sitka spruce

FRES25 Larch

FRES26 Lodgepole pine

FRES27 Redwood

FRES28 Western hardwoods

FRES29 Sagebrush

FRES34 Chaparral-mountain shrub

FRES35 Pinyon-juniper

FRES36 Mountain grasslands

More info on this topic.

This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

More info for the terms: forest, shrub, woodland

KUCHLER [151] PLANT ASSOCIATIONS:




K001 Spruce-cedar-hemlock forest

K002 Cedar-hemlock-Douglas-fir forest

K003 Silver fir-Douglas-fir forest

K004 Fir-hemlock forest

K005 Mixed conifer forest

K006 Redwood forest

K007 Red fir forest

K008 Lodgepole pine-subalpine forest

K010 Ponderosa shrub forest

K011 Western ponderosa forest

K012 Douglas-fir forest

K013 Cedar-hemlock-pine forest

K014 Grand fir-Douglas-fir forest

K015 Western spruce-fir forest

K016 Eastern ponderosa forest

K017 Black Hills pine forest

K018 Pine-Douglas-fir forest

K020 Spruce-fir-Douglas-fir forest

K021 Southwestern spruce-fir forest

K022 Great Basin pine forest

K023 Juniper-pinyon woodland

K024 Juniper steppe woodland

K026 Oregon oakwoods

K028 Mosaic of K002 and K026

K029 California mixed evergreen forest

K030 California oakwoods

K032 Transition between K031 and K037

K033 Chaparral

K034 Montane chaparral

K036 Mosaic of K030 and K035

K037 Mountain-mahogany-oak scrub

K038 Great Basin sagebrush

K050 Fescue-wheatgrass

K055 Sagebrush steppe

K056 Wheatgrass-needlegrass shrubsteppe

More info on this topic.

This species is known to occur in association with the following Rangeland Cover Types (as classified by the Society for Range Management, SRM):

More info for the terms: cover, shrubland, woodland

SRM (RANGELAND) COVER TYPES [235]:




104 Antelope bitterbrush-bluebunch wheatgrass

105 Antelope bitterbrush-Idaho fescue

107 Western juniper/big sagebrush/bluebunch wheatgrass

109 Ponderosa pine shrubland

110 Ponderosa pine-grassland

201 Blue oak woodland

206 Chamise chaparral

207 Scrub oak mixed chaparral

208 Ceanothus mixed chaparral

209 Montane shrubland

210 Bitterbrush

314 Big sagebrush-bluebunch wheatgrass

315 Big sagebrush-Idaho fescue

316 Big sagebrush-rough fescue

317 Bitterbrush-bluebunch wheatgrass

318 Bitterbrush-Idaho fescue

319 Bitterbrush-rough fescue

320 Black sagebrush-bluebunch wheatgrass

321 Black sagebrush-Idaho fescue

322 Curlleaf mountain-mahogany-bluebunch wheatgrass

401 Basin big sagebrush

402 Mountain big sagebrush

403 Wyoming big sagebrush

411 Aspen woodland

412 Juniper-pinyon woodland

413 Gambel oak

415 Curlleaf mountain-mahogany

416 True mountain-mahogany

417 Littleleaf mountain-mahogany

418 Bigtooth maple

419 Bittercherry

420 Snowbrush

421 Chokecherry-serviceberry-rose

Snowbrush ceanothus is top-killed by fire [228].

More info for the terms: presence, shrubs

Snowbrush ceanothus provides poor forage for domestic cattle, sheep, and horses
[177,197,240].
Snowbrush ceanothus is a valuable year-round browse species for deer and elk [50,100,113,153,154,160,161,164,172,200,296]. However,
some authors report that deer and elk
will browse snowbrush ceanothus only if better forage is unavailable [197,240]. Shrubfields in the northern Rocky Mountains
are an important source of browse and habitat for ungulates, and the presence of
snowbrush ceanothus may extend their value by providing forage after other
desirable shrubs have grown out of reach [164].

Snowbrush ceanothus is of moderate to high importance for mule deer,
white-tailed deer, mountain goat, mountain sheep, elk, and moose winter browse [33,121,128,137,146,152,169,212,267].
In 1 California study, however, snowbrush ceanothus ranged from only 0.2 to 3.6% of mule deer stomach contents in the months of October though April
[29]. Because it is evergreen and seldom grows over 3
feet tall, snowbrush ceanothus is generally available as browse [146]. Makela
[169] noted that elk utilization of
snowbrush ceanothus may be generally higher in more forested areas than in open
shrubfield vegetation, though Irwin and Peek [137] found that winter elk use of
snowbrush ceanothus was higher in seral brushfields. As coastal mule deer, bighorn sheep, and caribou winter browse, it is of low importance
[33].

Small mammals and birds eat the seeds of snowbrush
ceanothus [243,244,271].
Snowbrush ceanothus has also been recorded in stomach samples of mountain lions [270].

More info for the terms: shrub, tree, vine

Plant Communities and Associates:
Snowbrush ceanothus is common in ponderosa pine (Pinus ponderosa) communities
[53,80,174,191,203,275,276,285,291]. Plant associates in these communities
include bitterbrush (Purshia tridentata) [19,53,114,191,203,276,291],
willow (Salix spp.), common snowberry (Symphoricarpos
albus), ninebark (Physocarpus malvaceus),
oceanspray (Holodiscus discolor), smooth sumac (Rhus glabra) [291], rose (Rosa spp.), serviceberry (Amelanchier
spp.) [174,291], quaking aspen (Populus
tremuloides) [174], giant chinquapin (Chrysolepis
chrysophylla), prince's pine (Chimaphila umbellata) [20,203], Gambel oak
(Quercus gambelii) [53], curlleaf mountain-mahogany (Cercocarpus ledifolius)
[114], manzanitas
(Arctostaphylos spp.) [19,53,191,203,276],
bittercherry (Prunus emarginata), white spirea (Spiraea
betulifolia), redstem ceanothus (Ceanothus sanguineus) [291], Ross' sedge (Carex rossii)
[19], Idaho fescue (Festuca idahoensis) [114,276], and western needlegrass [191,276]

In the intermountain ponderosa pine region, snowbrush ceanothus forms extensive
shrubfields with bush chinquapin (Chrysolepis sempervirens), greenleaf
manzanita (Arctostaphylos patula), menziesia (Menziesia ferruginea), Rocky Mountain
maple (Acer glabrum), ninebark, and willows [105].

In lodgepole pine communities (Pinus
contorta) [226,276,285], snowbrush ceanothus occurs with ponderosa pine [226,276], white fir
(Abies concolor) [276],
white spruce (Picea glauca), paper birch (Betula papyrifera), limber pine (Pinus flexilis), common juniper (Juniperus communis), quaking
aspen, bearberry (Arctostaphylos uva-ursi), Oregon-grape (Mahonia repens),
rose, red raspberry (Rubus idaeus), western
snowberry (Symphoricarpos
occidentalis), grouse whortleberry (Vaccinium scoparium) [226], greenleaf manzanita, pinemat manzanita
(Arctostaphylos nevadensis), and bitterbrush [276]

In Douglas-fir forests (Pseudotsuga menziesii)
[80,124], snowbrush ceanothus occurs with lodgepole pine, grand fir
(Abies grandis),
western redcedar (Thuja plicata), western hemlock (Tsuga heterophylla)
[4], vine
maple (Acer circinatum) [93], ninebark [11],
Oregon boxwood (Paxistima myrsinites) [4,93,124], bearberry [4,93], mountain snowberry,
chokecherry, currant, big sagebrush, Rocky Mountain maple, mountain-mahogany
(Cercocarpus montanus), russet buffaloberry (Shepherdia canadensis), common
snowberry [65,210], willow [65,124], Oregon-grape, Wood's rose (Rosa woodsii), white spirea [65], big
huckleberry (Vaccinium membranaceum), dwarf Oregon-grape
(Berberis nervosa), and trailing blackberry (Rubus ursinus) [93].

In mixed conifer communities [130,145,275], snowbrush ceanothus occurs with sugar pine (Pinus lambertiana)
[76,145], ponderosa pine [24,76,130,145,275], lodgepole pine [24,275], Douglas-fir
[24,76,130], incense-cedar (Calocedrus
decurrens), white fir [76,130,145], grand fir [24,145], western hemlock, western
redcedar, California red fir (Abies
magnifica),
tanoak (Lithocarpus densiflorus), Jeffrey pine
(Pinus jeffreyi), and California black oak (Quercus kelloggii) [145]. Understory associates include willow
[24,76], Oregon boxwood [130], bitterbrush,
needlegrass (Achnatherum spp.),  sedge (Carex spp.) [275], common
snowberry [76], bearberry (Arctostaphylos uva-ursi) [130], manzanita [76,145,275],
chinquapin [76,130,145,275], bittercherry,
deerbrush (Ceanothus
integerrimus), whitethorn ceanothus (C. cordulatus) [145], mahala mat (C. prostratus) [76,145], redstem ceanothus, and pinegrass (Calamagrostis rubescens)
[24].

Snowbrush ceanothus occurs in white fir-California
red fir forests [5,88] with ponderosa pine [88,122],
Jeffrey pine [122], bush chinquapin [88],
greenleaf manzanita [88,122], mahala mat [5,122],
snowberry [5], rubber rabbitbrush, and wax currant (Ribes cereum) [122]. 

Snowbrush ceanothus occurs in Jeffrey pine-white fir forests
[14,34,35] with sugar pine [34], lodgepole pine [34,35], golden
currant (Ribes aureum), incense-cedar [34], mahala mat, bush chinquapin,
greenleaf manzanita [34,35], wax currant, and bittercherry [35].

Snowbrush ceanothus is a common or dominant component
in seral shrubfields of the northern Rockies [21,208,237].
Plant associates in these communities include Scouler willow (Salix
scouleriana), Rocky Mountain maple, Saskatoon serviceberry (Amelanchier alnifolia)
[21,51,120,166,208], currant
(Ribes spp.), whitethorn ceanothus [170], redstem ceanothus
[21,51,208],
Oregon boxwood [21,51,120,208], red
elderberry (Sambucus racemosa), russet buffaloberry [237], white spirea, common
snowberry [21,208], menziesia [21], ninebark [21,51,166,208], thimbleberry (Rubus parviflorus), bittercherry
[120,208], oceanspray [51,208], Pacific dogwood (Cornus nuttallii),
red-osier dogwood (Cornus sericea), big huckleberry, and Utah honeysuckle (Lonicera utahensis) [208].
Snowbrush ceanothus may comprise up to 80% of the shrub volume in these
communities [51].

In quaking aspen communities [16,49,50,134,285],
snowbrush ceanothus occurs with chokecherry (Prunus virginiana), mountain snowberry
[49,50], serviceberry, and
Oregon boxwood [49,50,134].

In pinyon-juniper (Pinus spp.-Juniperus
spp.) woodlands [80,147],
snowbrush ceanothus occurs with serviceberry, big sagebrush (Artemisia tridentata),
rubber rabbitbrush, green rabbitbrush (C.
viscidiflorus), green
ephedra (Ephedra viridis), bitterbrush, desert gooseberry (Ribes
velutinum), blue elderberry (Sambucus cerulea), and mountain
snowberry (Symphoricarpos oreophilus) [147].

In mountain brush communities [14,15,42,221,285], snowbrush ceanothus commonly occurs with Rocky Mountain maple
[202],
bigtooth maple [42], big sagebrush [15,42,221],
black sagebrush (Artemisia nova) [42], bearberry [14,42],  ceanothus (Ceanothus spp.) [42], serviceberry
[15,42,42,44,202,221], Stansbury
cliffrose (Purshia mexicana var. stansburiana) [42], bitterbrush [15,42], snowberry [15,42,44,202,221], Oregon boxwood
[15], curlleaf mountain-mahogany [42,119], true mountain-mahogany [42], ninebark
[15,221], rubber rabbitbrush [202], oaks (Quercus spp.) [42,202,221], New Mexico locust (Robinia neomexicana) [42],
Wood's rose [202], currant [44,202],
Prunus spp. [14,15,42,44,202,221], quaking aspen [44,202], and Idaho fescue [44].

In montane chaparral communities [36,119], snowbrush ceanothus commonly occurs with manzanita
[31,36,60,119],  bush chinquapin [31,36,60,119], ceanothus (Ceanothus spp.)
[31,36,119], currant [44,202], curlleaf mountain-mahogany, rubber rabbitbrush [119], silktassel (Garrya
spp.) [36], quaking aspen [44,202], oaks (Quercus spp.) [31,36,60], and Prunus
spp. [36,60,119]. Common tree species that may be present in these communities include
white fir, California red fir, sugar pine, ponderosa pine, Jeffrey
pine, and incense-cedar [36]. 

Plant Community Dominance:
Classifications in which snowbrush ceanothus is
identified as a plant community dominant are:



Colorado [16]

Idaho [242,243,244,245,246,247,248,249]

Nevada [162]

Oregon [130,276]
Washington [93]

Snowbrush ceanothus forms "layer groups",
or early seral shrub layers, in grand fir habitat types, co-dominating these
layers with Sitka alder (Alnus viridis ssp. sinuata), sticky
currant (Ribes viscosissum),
Scouler willow, white spirea, Utah honeysuckle, thimbleberry, Rocky Mountain maple, or
big huckleberry [242,245,247]. In Douglas-fir habitat types, snowbrush ceanothus shrub
layers are formed with pinegrass, currant, Scouler willow,
Prunus spp., serviceberry, mountain snowberry, white spirea, ninebark, or
Rocky Mountain maple [243,244,246,248,249].

More info for the term: shrub

Shrub

The following table presents mean nutrient content of snowbrush ceanothus branch
material in the absence of recent fire at 4 sites in northwestern Montana [241]:

 
micrograms per gram
Location Ca Cu Fe K Mg Mn N Na P Zn % ash
Site 1 (SW aspect) 5,819 7.5 65 4,368 1,046 134 15,890 104 358 16 3.0
Site 2 (SW aspect) 8,667 6 65 4,617 1,068 126 16,527 123 374 21 3.0
Site 3 (SE aspect) 7,188 7 77 4,673 1,177 69 17,226 113 399 19 3.2
Site 4 (SE aspect) 9,665 7 86 4,270 1,080 116 17,325 99 390 26 3.4

The foliage nutrient content of snowbrush ceanothus
at 4 sites in Oregon is presented in the following table [287]:


Location
% dry weight
parts per million
  P K Ca Mg S B Zn Fe Mn
site 1 0.18 0.90 0.55 0.17 0.06 31 36 55 65
site 2 0.14 0.95 0.52 0.15 0.06 21 12 60 120
site 3 0.16 1.00 0.46 0.16 0.07 30 18 50 105
site 4 0.14 0.90 0.52 0.14 0.12 20 30 75 290

Snowbrush ceanothus has fair energy value and fair protein value for domestic
livestock [80]. In 1 analysis, the crude protein content of
snowbrush ceanothus ranged from 7.1% in January to 18.3% in June [29].

Mean nutritional content of snowbrush ceanothus for elk and domestic sheep is
presented below [32]:


% sheep IVDMD* % elk IVDMD % crude protein % Calcium % Phosphorus Ca:P
57.0 57.8 14.2 1.28 .21 6.0

*In-vitro dry matter digestibility

The following table presents differences in the nutritional value of
snowbrush ceanothus on burned and unburned sites. Sites were prescribe burned
in October 1982, and study samples were subsequently collected during the
summers of 1982 and 1983 [32].

 
% sheep IVDMD
% elk IVDMD
% crude protein
% Calcium
% Phosphorus
Ca:P
  1982 1983 1982 1983 1982 1983 1982 1983 1982 1983 1982 1983
Burned 49.1 54.1 47.4 61.9 18.2 14.5 0.93 1.34 0.23 0.20 4.0 6.1
Unburned 48.7 53.0 47.5 60.9 14.4 15.0 1.20 1.72 0.14 0.21 8.4 7.0

Snowbrush ceanothus nutritive value does not appear substantially affected by
burning in quaking aspen stands. Information on the percent crude protein and in-vitro dry
matter digestibility of snowbrush ceanothus during the 3rd year postfire growing
season, for both burned and unburned aspen stands, is presented below [49]:

 
% Crude Protein
% IVDMD
Date 7/22 8/9 8/24 9/13 9/29 7/22 8/7 8/24 9/13 9/29
Burned 18.8 17.0 15.1 13.2 13.6 61.9 61.7 65.4 54.2 52.9
Unburned 19.7 17.1 15.9 13.7 14.4 63.8 63.3 58.3 52.2 54.8

As a nitrogen fixing plant, snowbrush ceanothus may provide high quality
browse. The following table presents information on the biomass and nitrogen
capital, according to plant part, of a snowbrush ceanothus stand on H. J.
Andrews Experimental Ecological Reserve. Data are means and 1 standard error [67].

  Biomass
Nitrogen capital
Snowbrush ceanothus component  kg/ha  % kg/ha
Leaves 3,551 + 945 1.78 63.4 + 16.8
Stems 30,339 + 2,880 0.36 109.2 + 10.4
Roots 8,040 + 2,280 0.43 34.6 + 9.8
Nodules 750 + 350 2.37 17.8 + 8.3
Totals 42,680   225.0

CA CO ID MT NV
OR SD UT WA WY

AB BC

The palatability of snowbrush ceanothus has been rated as follows [80]:

  Utah Wyoming Montana
Cattle poor fair poor
Domestic sheep poor good fair
Horses poor fair poor

Hill [128] found that snowbrush ceanothus is highly
to moderately palatable for white-tailed deer in South Dakota during late fall and winter, but
unpalatable during the remainder of the year.

More info on this topic.

More info for the terms: fruit, seed

Snowbrush ceanothus seeds germinate in the spring [144]. Leaf buds of snowbrush
ceanothus break from mid-April to early June, and leaves
continue growth until early July  [225,231]. Flowering begins in May or June and ends as late as September
[80,225,231].
Snowbrush ceanothus blooms sporadically at higher elevations, but at lower
elevations and in warmer climates, blooms can be expected from May to June [37].
Fruit
ripens from late June to early August, and seed fall starts in August [225,231,240].

More info for the terms: cover, density, fire severity, forest, prescribed burn, prescribed fire, root crown, seed, severity, shrub

Snowbrush ceanothus establishes from seed [63,85,109,288] and sprouts from the
root crown [40,41,59,65,66,81,90,163,213,217,240,256,295] after fire. Postfire
recovery of snowbrush ceanothus can be expected within 2 to 5 years in the
Intermountain region [295]. Snowbrush ceanothus usually increases following
fire, often dramatically [40,41,65,75,90,140,295]. Snowbrush ceanothus seedlings often appear on sites following fire where it was previously
uncommon or not present [75,164,165,167,194,217,223,251,256,269,293].
Following a severe fire in Douglas-fir in Oregon, snowbrush ceanothus seedlings
were found on lightly and
severely burned areas, but they were absent on adjacent, unburned areas [85]. Following fall prescribed burning in a quaking aspen stand in Idaho, biomass of snowbrush
ceanothus increased substantially by sprouting [43].


Seedling Density: A flush of
snowbrush ceanothus seedlings appeared in quaking aspen and quaking aspen/mixed conifer stands
the 1st year after the Idaho prescribed fire. The seedling density decreased substantially by the 2nd
postfire year; a much smaller decrease occurred in subsequent years. The average number of snowbrush ceanothus seedlings/ha in 3 different stands
over 4 postfire years is presented below [43]:


 
Year after fire
Stand 1 2 3 4
Aspen/mixed conifer 26,600 9,800 3,600 6,100
Upper-elevation aspen 25,500 13,100 9,000 12,300
Lower-elevation aspen 7,700 3,600 3,400 1,900

In Idaho, Lyon [165] found 4,000 snowbrush ceanothus
seedlings/1,000 ft2 1 year after an August prescribed fire. By the 2nd
postfire year,
over 40% of the seedlings had died, and by the 7th postfire year, only 20% of the original
seedlings were still alive [165]. Seedling densities following fire are
not uniform, and a study in a Douglas-fir stand in Oregon found snowbrush
ceanothus densities ranging from 200 seedlings/ha to 30,000 seedlings/ha [190]. Weatherspoon
[282] reported up to 410,000 snowbrush ceanothus
seedlings/hectare following a moderate-consumption prescribed fire in a
white fir forest in California. In an Oregon Douglas-fir forest, Gratkowski [109] found that although
snowbrush ceanothus seedlings emerged on both logged/unburned and logged/burned
sites, seedlings were far more numerous on burned sites.

Fire Severity: Higher densities of snowbrush ceanothus may be related to increased fire severity
[115,140,239,243]. Dense stands of snowbrush ceanothus often develop following a severe burn, as
seeds stored in the soil are stimulated to germinate [40,41,116,154,163,217,234,240,250]. In northeastern
Oregon, snowbrush ceanothus cover increased from 3% to as much as 32% 5 years
following a severe burn [140]. Snowbrush ceanothus may
dominate a site within 2 to 11 years [41,43,75,239,253,254].
Following a severe fire in a western larch-Douglas-fir forest in western Montana,
snowbrush ceanothus formed a nearly closed shrub layer with 94% cover by the
13th postfire year [254,257]. Another severe fire in
a Douglas-fir forest in Washington resulted in 10% snowbrush ceanothus cover by
the 4th postfire year, increasing from 1% prior to the fire [266].

Height Growth: Snowbrush ceanothus height growth
after fire is variable and may increase with the severity of the burn [101].
Snowbrush ceanothus seedlings can be expected to grow 3 to 5
feet tall within 3 postfire years in the Payette National Forest, Idaho [81]. Following a prescribed burn
in Idaho, snowbrush ceanothus plants reached 2.4 feet tall by 7 postfire years [165]. However, on another site in Idaho, snowbrush ceanothus
plants were only 2.8
inches (7 cm) tall after 1 year and only 2.6 feet (0.8 m) 12 years
following broadcast burning [300].

More info for the terms: adventitious, ground residual colonizer, shrub

POSTFIRE REGENERATION STRATEGY [258]:




Small shrub, adventitious bud/root crown

Ground residual colonizer (on-site, initial community)

More info for the terms: density, duff, layering, root crown, seed, stratification, top-kill, tree

Snowbrush ceanothus spreads by seed and vegetatively by sprouting and layering
[31,121].

Breeding system: No information

Pollination: No information

Seed production: Snowbrush ceanothus produces abundant seed crops [240].
It 1st produces seed at about 3 to 6 years of age [63,263], and continues producing until past age 20 [263]. Sprouts can produce
prolific seed crops 8 years after top-kill [63]. Snowbrush
ceanothus in
Oregon produced up to 100,000 seeds per acre (250,000 seeds/hectare) [109].

Seed dispersal: When Ceanothus seeds
ripen, they are forcibly ejected from the pods [63,144]. The heavy snowbrush ceanothus seeds generally stay
where they fall, gradually filtering into the duff and soil unless they are
carried off by small animals [63,75,144,149,243,271,295]. 

Seed banking: Snowbrush ceanothus seed is stored in the soil [40,148,154] for
up to 200 years [154], and can regenerate from seed stored in the soil
for up to "several centuries" [21,63,91,109,143].
In British Columbia, germination of soil-stored seed occurred following
fire on sites where snowbrush ceanothus had been excluded at least 200 years [293]. Counts made on tree
stumps indicated that the intermission between
2 generations of snowbrush ceanothus might be as long as 575 years [301,303]. Snowbrush ceanothus contributed 25% of the seeds found in soil samples taken
from central Idaho Douglas-fir and grand fir habitat types [149]. Snowbrush ceanothus seeds are less
successfully stored in wet soils [245].

Germination: Snowbrush ceanothus has a very hard,
impermeable seedcoat that must be cracked, abraded, or exposed to heat in order for
germination to occur [79,109,123,144,148,163,197,293,303].
Though exposure to heat is most effective in promoting germination, other
disturbance (e.g. timber harvest) may stimulate snowbrush ceanothus germination
by abrading the seedcoat [303]. Germination is improved by stratification
[109,197]. Heating
or breaking the seed coat allows the seeds to imbibe water and swell, but
germination is unlikely if seeds are not exposed to cold stratification [109,123,144,197,218,219]. The mechanism for fire-induced germination in snowbrush ceanothus is a heat-induced,
irreversible cracking of the hylar fissure in the seedcoat, which
allows water to enter the seed and physiological processes to begin [22,109]. Temperatures of
176 to 203 degrees Fahrenheit (80-95 oC) are optimal to break the
seedcoat [109,163]. Snowbrush ceanothus seeds may also germinate
without high temperatures (e.g. on unburned sites), but snowbrush ceanothus
stands develop more rapidly and more completely
following heat exposure (burned sites) [63,109,288]. In a study conducted in Douglas-fir and grand fir habitat types, snowbrush ceanothus seeds found
in the soil were 91% viable [148].

Seedling establishment/growth: Although large
numbers of seeds typically germinate after fire, snowbrush ceanothus may
experience high early mortality [63].
In general, snowbrush ceanothus is a slow-growing species [301,303]. Height growth of seedlings
is slow for 3-5 years and then is rapid until about 10 years when it begins to
level off [63,189]. Zavitovski
[303] found that after 5 years, snowbrush
ceanothus may be less than 3 feet (1 m) tall, but doubles its height in the next 5 years. Then height growth slows, gaining only 1.5 feet (0.5 m) in the following 5 years
[303]. A typical snowbrush ceanothus stand in Oregon or
California reaches 2 to 8 feet after 10 years; stand height may sometimes
decrease between age 15 and 50 as older stems die back [63].

Asexual regeneration: Snowbrush ceanothus sprouts from the root crown [138,139] following damage to stems
and/or top removal [30,31,63,121,162,178,238]. Sprout growth of 20 to 25 inches
(51-65 cm) after 1 year, and growth of 3 to 7 feet (1.0-2.1 m) after 5 years has been
observed. The ability to sprout may be a function of age and
vigor of the plant when it is damaged. In 1 Cascade Range study, the percentage
of sprouting plants decreased from 100% for 5-year-old plants to 50% for
11-year-old plants [63]. However, vigorous
sprouting followed the cutting of 35- to 50-year-old snowbrush ceanothus in the Sierra
Nevada [59,63].
Snowbrush ceanothus may increase in density by layering.
Layering results when stems are forced close to the ground, bringing them in
contact with the soil and allowing the branches to root [31].

More info on this topic.

This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):

BLM PHYSIOGRAPHIC REGIONS [25]:




2 Cascade Mountains

4 Sierra Mountains

5 Columbia Plateau

6 Upper Basin and Range

8 Northern Rocky Mountains

9 Middle Rocky Mountains

10 Wyoming Basin

11 Southern Rocky Mountains

12 Colorado Plateau

15 Black Hills Uplift

More info on this topic.

More info for the terms: climax, cover, fire interval, forest, mean fire interval, phase, sere, shrub, shrubs, succession, tree

Snowbrush ceanothus has been described as moderately shade tolerant [121] to very intolerant
[11,60,163,242]: It grows on open, sunny sites [70,127,132,136,154,176,209,240]
and in wooded areas [82,127,135,176]. Though snowbrush ceanothus occurs as an
understory species [124,173,198,249,278,286,293], it is soon shaded out
with increasing development of tree cover [11,63,154,163,182,199,242,249,300]. Snowbrush ceanothus occurs on both undisturbed and disturbed sites, with
snowbrush ceanothus canopy cover [19,63,95,182,198] and occurrence [23,136] increasing under more open site conditions.
Under patchy tree canopies, snowbrush ceanothus may persist for 40 years or more
after trees establish [249].

Snowbrush ceanothus is an early to mid-seral species
[7,60,63,75,85,116,150,242,244,245,249,255,288]. It invades recently disturbed sites
[1,58,63,68,74,99,118,121,292], particularly burned
sites [52,75,85,116,140,240]. Snowbrush ceanothus is essentially absent in mature seral and old-growth stages, often becoming a stand component after fire [11,223,288].
In several Douglas-fir habitat types [11,91,102,256,304] and in ponderosa pine habitat
types [6,272], snowbrush
ceanothus is common in early seral stages (within 1-7 years) following
disturbance. The Douglas-fir-snowbrush ceanothus community type is characteristic of
habitats that have been recently (within the last 100 years) and
repeatedly burned [93]. Snowbrush ceanothus also occurs in dense stands of montane chaparral following major disturbance
[14], though it may be eliminated from the chaparral after 40 years [301]. For
further information on postfire succession of snowbrush ceanothus, see
"Plant Response to Fire" in the "Fire Effects" section of
this summary.

Snowbrush ceanothus can be described as a seral dominant, becoming common
after major disturbances, especially fire [12,18,148,162,163,194,229]. Seral shrubfields, of which
snowbrush ceanothus is a major component, result from repeated disturbance
[21,57,71,71,103,137,170,172,208]. Snowbrush ceanothus may dominate this seral vegetation [57,63,68,104,120,125,168,172,182,237,299,304] and retard succession
[63,104].

Douglas-fir: Snowbrush ceanothus is generally considered an important early to
mid-seral species in most Douglas-fir forests of the northern Rockies and
Pacific Northwest. However, in some locations Douglas-fir forests are
sufficiently open to allow snowbrush ceanothus to become a persistent, if not
permanent, member of the community. It occurs as a climax dominant in some
open Douglas-fir forests of southwestern Oregon and in eastern Montana habitat
types on decomposed granitic substrates [63]. In Douglas-fir
forests of the western Cascades, snowbrush ceanothus generally dominates the
middle or tall shrub phase of succession from years 5 through 10 [115]. Here it
replaces initial weedy annual, biennial, and short-statured perennial invaders
[116]. Snowbrush ceanothus typically competes effectively with fireweed (Epilobium
angustifolium) by postfire year 6 and can become dominant by year 9 [94].
Earlier increases in snowbrush ceanothus have also been noted, with this shrub
dominating some shrubfields as soon as 4 or 5 growing seasons after fire [83].
Snowbrush ceanothus generally persists for 20 to 40 years in the Cascades [63],
although some stands may become decadent 10 to 15 years after disturbance
[63,301]. Stands 40 or more years of age generally have only scattered dead
shrubs [301]. South slopes offer the greatest potential for development of
snowbrush ceanothus-dominated brushfields in these Douglas-fir types [206].
Shrubs decline rapidly as shade levels increase, and in parts of the northern
Rockies, shrubs may become senescent by year 10 [301].

Western hemlock-western redcedar: Snowbrush ceanothus can dominate western
hemlock-western redcedar-grand fir forests of the northern Rockies within 2 or 3
years after fire [157].  Snowbrush ceanothus cover
typically declines rapidly in western hemlock-western redcedar forests of
northern Idaho [159,199].

Grand fir: Snowbrush ceanothus is an important component of the initial shrub
sere that following disturbance in grand fir habitat types
and can become established by the 1st year after disturbance [300]. In
north-central Idaho, it is particularly abundant on north slopes at higher
elevations and can become a dominant shrubfield species by year 12 [299]. These
shrubfields decline rapidly as shade increases. However, long-lived snowbrush
ceanothus communities are prevalent on rocky outcrops in grand fir forests of
Oregon and Washington [92].

Ponderosa pine: Snowbrush ceanothus assumes a dual successional role in
ponderosa pine and mixed-conifer forests of the Northwest. Where forests are
relatively open, it can grow as a long-lived seral shrub or climax dominant, but
where densely forested stands develop, snowbrush ceanothus declines rapidly as it is
overtopped. Snowbrush ceanothus and bitterbrush occur as understory dominants in open ponderosa pine forests of south-central Oregon [92]. In
an Oregon ponderosa pine-white fir forest, snowbrush ceanothus was only dominant
on sites where the mean fire interval was 15 years or less over the past 250
years, and it was almost absent where the interval was greater than 20 years [181,182].
Snowbrush
ceanothus also grows as a climax species in some open ponderosa pine woodlands
on the east side of the Cascades [63].

In mixed-conifer forests of Oregon, snowbrush ceanothus and other tall shrubs become dominant within 14
years after timber harvest but begin to decline within 20 years [150].

The currently accepted name of snowbrush ceanothus is Ceanothus velutinus
Dougl. ex Hook. (Rhamnaceae) [70,82,142,284,285]. Infrataxa are as follows:




Ceanothus velutinus var. hookeri M.C. Johnston [127,142], Hooker's ceanothus

Ceanothus velutinus var. velutinus [70,127,129,142], snowbrush ceanothus



Ceanothus × lorenzenii (Jepson) McMinn is a cross between
snowbrush ceanothus and whitethorn ceanothus (C. cordulatus) [142].

More info for the terms: hardwood, natural, reclamation, restoration, seed, softwood, stratification

Snowbrush ceanothus is recommended for land reclamation, range restoration, and amenity planting
[87,192,193,216,271]. Snowbrush ceanothus' ability to rapidly invade disturbed areas,
its
persistence, and its extensive soil-binding roots make snowbrush ceanothus valuable
for reducing erosion potential [121,197,216]. The
nitrogen-fixing ability of snowbrush ceanothus may be useful in replenishing
soil nutrients in disturbed areas [39,63,216,295].

Artificial regeneration: Seed dormancy of snowbrush ceanothus can be broken by a hot water soak at
175 degrees Fahrenheit (75 oC) for 1/2 day [45]. Germination is
improved by stratification,
moistening and storing the seed for a few weeks near 32 degrees Fahrenheit (0 oC)
[109,197]. Borland [37] recommends
seed be soaked in water at 194 degrees Fahrenheit (90 oC) for several hours, then be
subjected to a moist and cool (34-41 oF (1-5 oC)) period for 63 to 84 days.
Hudson and Carlson [131] found that placing snowbrush ceanothus seed in water at
190 degrees Fahrenheit (88 oC) allowing it to cool followed by
stratification at 36 degrees Fahrenheit (2 oC) for 4 to 5 months was
an effective pretreatment. Heit
[123] found that 30 minutes in sulfuric acid or a hot-water soak of 180 to
190 degrees Fahrenheit, followed by a moist prechilling of 2 months, resulted in
optimum germination rates. The
best germination is achieved when the treated seed is planted 0.25 to 0.5 inch
(0.5-1.3 cm) deep and temperature is alternated between 86 degrees Fahrenheit
(30 oC) for 8 hours and
68 degrees Fahrenheit (20 oC) for 16 hours [37]. Fall planting of snowbrush
ceanothus seeds is recommended, allowing for a natural required stratification period
[123,193]. Seedling growth may be encouraged by nitrogen fertilization, and is
improved by drier soil conditions [131].

Snowbrush ceanothus can be propagated from hardwood
or softwood cuttings [240]. Semiripe tip cuttings treated with 0.8% idolebutyric
acid can be rooted under mist with 70 degrees Fahrenheit (21 oC) bottom heat, though
rooted cuttings are difficult to overwinter [37]. 

Transplanting snowbrush ceanothus has been described as both effective [121,271] and unsuccessful
[154].

Ceanothus velutinus, with the common names snowbrush ceanothus, red root, and tobacco brush, is a species of shrub in the family Rhamnaceae. It is native to western North America from British Columbia to California to Colorado, where it grows in several habitat types including coniferous forest, chaparral, and various types of woodland.

Ceanothus velutinus là một loài thực vật có hoa trong họ Táo. Loài này được Douglas ex Hook. mô tả khoa học đầu tiên năm 1831.