Picea breweriana S. Watson

Trees to 40m; trunk to 1.5m diam., typically buttressed; crown conic. Bark gray to brown. Branches drooping; twigs pendent, elongate, slender, gray-brown, finely pubescent. Buds gray-brown, 5--7mm, apex rounded. Leaves 1.5--3cm, flattened or broadly triangular in cross section (abaxial surface rounded or slightly angular), rather rigid, abaxial surface dark green with stomatal bands absent, adaxial surface glaucous with conspicuous stomatal bands separated by slight ridge or angle, apex blunt (especially on older leaves). Seed cones 6.5--12cm; scales fan-shaped, 15--20 ´ 15--20mm, rigid, margin at apex entire to slightly erose.

Montane to subalpine forests of the Siskiyou Mountains; 1000--2300m; Calif., Oreg.

Brewer spruce
weeping spruce

More info for the term: presence

Brewer spruce is a native, endemic conifer. It has a distinctive,
drooping appearance caused by the presence of thousands of long,
ropelike branches hanging from all but the topmost horizontal limbs
[14,18,19,23]. At maturity, Brewer spruces usually reaches 80 to 100
feet (24-30 m) in height [16], but can reach up to 172 feet (52 m) in
height [21]. Diameters range from approximately 3.8 feet (117 cm) [18]
to up to 4.5 feet (1.35 m) in some areas [21]. The bark is thin and
broken into long, thin, appressed scales [14,16].

The leaves are obtuse, flat on top, and rounded underneath, and spread
from all sides of the branchlets. The male cones are stalked and oblong
(3 to 4 inches [7-10 cm] long). The seeds are 0.12 inch (3 mm) long
[14,16].

The root system generally is shallow; however, on deeper soils, a few
vertical roots may extend several meters [18].

Brewer spruce can live as long as 900 years [21].

Brewer spruce is endemic to the Klamath region of northwestern
California and adjacent Oregon. It is distributed from from Del Norte,
Trinity, and Siskiyou counties in California to Curry and Josephine
counties in Oregon [11,14,18]. The best developed stands are located
on high ridges and upper valleys of the Klamath, Shasta-Trinity, and Six
Rivers National Forests of California and in the Siskiyou and Rogue
River National Forests of Oregon [11,18,20].

More info for the term: fire regime

Brewer spruce is not fire resistant; the thin bark, drooping nature of
the branches, and shallow root system make it sensitive to fire
[17,18,23]. Fire sensitivity appears to have limited the range of
Brewer spruce [18]; it is largely confined to fire-resistant open
forests on north-facing slopes or rocky ridges [17,23].

FIRE REGIMES :
Find 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".

More info for the term: fuel

Brewer spruce serves as a medium fuel type [2].

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More info for the term: phanerophyte

Phanerophyte

More info for the terms: association, herbaceous, serpentine soils, shrubs

Despite its restricted distribution, Brewer spruce has a broad
ecological amplitude. Its apparent limitations are high water tables
and frequent fires [17,18]. Brewer spruce is quite tolerant of soil
moisture stress, cold temperatures, low light, low-fertility soils, and
snow [13,18,21]. Although Brewer spruce can tolerate considerable soil
moisture stress, it is sensitive to high evaporation demands. Under
such demand, stomata close, halting photosynthesis [13,18,21].

Brewer spruce grows in a climate of cold, wet winters and warm,
relatively dry summers with respective temperature ranges of 30 to 41
degrees Fahrenheit (-1 to 5 deg C) and 52 to 68 degrees Fahrenheit
(11-20 deg C). Annual precipitation varies between 39 and 110 inches
(1,000-2,800 mm) [18].

Brewer spruce stands occur on north-, south-, east-, and west-facing
slopes, but the preferred habitat is steep, north-facing slopes [3,18].
Brewer spruce occurs on rocky ridges [18], cold hollows [14], and on dry
talus and moraines [17]. It never occurs in areas where the
soils are saturated during the growing season, such as boggy or wet
areas. The slope is generally 11 to 70 percent [18].

Brewer spruce grows on soils developed from sedimentary, granitic,
serpentine, and metavolcanic rock [18]. Most soils are shallow, rocky,
and undeveloped; however, Brewer spruce does occur on deeper soils [18].
Soil pH ranges between 4.6 and 7.2 on mica schist, meta volcanic,
granitic, and ultrabasic soils [21]. Soil depth varies between 12 and
50 inches (6.5-127 cm) [3]. Kruckeberg [9] lists Brewer spruce as an
indicator of serpentine soils. Heavy metals, especially iron and
nickel, can attain high levels in soil and plant tissues of Brewer
spruce [9].

Brewer spruce occurs at the elevations listed below [3,18]:

feet meters
Siskiyou Region 3,840-5,120 1,163-1,515
Eastern Klamath Region 4,500-7,500 1,370-2,290

The majority of Brewer spruce overstory associates are listed in the
Distribution and Occurrence frame. Other overstory associates not
mentioned previously include noble fir (Abies procera), sugar pine
(Pinus lambertina), Pacific yew (Taxus brevifolia), and Alaska cedar
(Chamaecyparis nootkatensis) [3,4,8,17,18]. Shrubs that occur in
association with Brewer spruce include Sadler oak, huckleberry oak
(Quercus vaccinifolia), greenleaf manzanita (Arctostaphylos patula),
pinemat manzanita (A. nevadensis), thinleaf huckleberry (Vaccinium
membranaceum), snowberry (Symphoricarpos hesperius), dwarf Oregon grape
(Berberis nervosa), and Labrador tea (Ledum glandulosum) [3,17,18].
Associates that occur in the herbaceous layer are beargrass (Xerophyllum
tenax), western prince's pine (Chimaphila umbellata), vanillaleaf
(Achlys triphylla), rattlesnake plantain (Goodyera oblongifolia),
Pacific trillium (Trillium ovatum), false Solomon's seal (Smilacina
stellata), queenscup (Clintonia uniflora), starflower (Tridentalis
latifolia), and groundsel (Senecio triangularis) [3,4,17,18].

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

205 Mountain hemlock
206 Engelmann spruce - subalpine fir
207 Red fir
211 White fir
215 Western white pine
224 Western hemlock
229 Pacific Douglas-fir
231 Port-Orford-cedar
234 Douglas-fir - tanoak - Pacific madrone
243 Sierra Nevada mixed conifer
244 Pacific ponderosa pine - Douglas-fir
247 Jeffrey pine
256 California mixed subalpine

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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):

FRES20 Douglas-fir
FRES21 Ponderosa pine
FRES23 Fir - spruce
FRES24 Hemlock - Sitka spruce

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

More info for the term: forest

K001 Spruce - cedar - hemlock forest
K004 Fir - hemlock forest
K005 Mixed conifer forest
K007 Red fir forest
K012 Douglas-fir forest
K029 California mixed evergreen forest

More info for the term: series

In a series of fires in 1987 that burned throughout the range of Brewer
spruce, low-intensity surface fires killed Brewer spruce in mixed
stands. In small stands on north, rocky slopes, Brewer spruce was
undamaged [18]. On granitic soils fire can be extremely damaging to
Brewer spruce because the shallow root system is damaged by heat
transfer to the soil [3].

Brewer spruce provides excellent wildlife habitat [4]. Cones and seeds
of Brewer spruce do not appear to be a preferred food for rodents [18].

More info for the terms: climax, codominant

Although Brewer spruce grows throughout the Klamath region, it usually
occurs in local, disjunct populations [17]. It is a minor component of
a variety of communities [24]. In some areas, Brewer spruce is a minor
climax species in stands dominated by California red fir (Abies
magnifica), white fir (A. concolor), or mountain hemlock (Tsuga
mertenmsiana) [3]. It occurs occasionally as a codominant in some
California red fir and western hemlock habitat types. Near the Russian
Peak area of the Marble Mountains of California, Brewer spruce is a
major component of the California red fir/northern twinflower (Linnaea
borealis) and California ref fir/huckleberry oak (Quercus vaccinifolia)
types [17]. This species also occurs in small dense stands on mostly
north-facing slopes, as individuals invading seral pine stands and
montane chaparral, and as scattered individuals in closed white fir
forests [17]. Brewer spruce is often an indicator of cold and wet
environments [2].

Brewer spruce is listed as a dominant or codominant overstory species in
the following published classification:

Preliminary plant associations of the Siskiyou Mountain Province [3].

More info for the term: tree

Tree

More info for the terms: basal area, mesic, natural, presence, seed

Brewer spruce is best managed on mesic sites that are characterized by
the presence of Sadler oak (Quercus sadleriana). Brewer spruce growth
is best in mixed stands with uneven-aged management [18]. Natural
regeneration of Brewer spruce is good under dense white fir-Brewer
spruce stands, but it does not regenrate as well in open conditions [3].

Little information on volume or yield of Brewer spruce is available.
The average total basal area of a few sampled stands is 205 square feet
per acre (47 sq m/ha), with an annual increment of 9 square feet per
acre (2 sq m/ha) [18].

Artificial propagation is best from seed. Some spruce seeds have been
stored without loss of viability for periods of 5 to 17 years [16].
Safford [26] describes methods of seed extraction and storage and
nursery practice.

Cooley spruce gall adelgid (Adelges cooleyi) is common in Brewer spruce
but does little harm. Seed chalcids (Megastigmus spp.) have been
observed in mature seeds of Brewer spruce. Parasitism by dwarf
mistletoe (Arceuthobium campylopodum) has been observed in 36 percent of
local populations. Brewer spruce is more susceptible to windthrow than
its associates because of its shallow root system. Shallow roots also
result in high incidences of root rot (Heterobasision annosum) in some
areas [18].

CA OR

In Europe, Brewer spruce is considered a popular ornamental [18].

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More info for the term: tree

Strobilus buds appear in early summer, accompanied by the shedding of
pollen, at which time the conelets are receptive. The male strobili
develop from axils of needles of the previous year's shoots. After
pollenation, the strobili dry and fall from the tree and the conelets
turn down and mature over the summer, into September and October.
Dissemination follows immediately [18].

Brewer spruce recovery from fire is generally slow. Seedlings are
unable to survive strong sunlight and are intolerant of moisture stress
[18]. The recovery of Brewer spruce from the extensive fires of 1987
may take decades or centuries [18]. Atzet and Wheeler [2], however,
reported that light fires may stimulate seeding or germination of Brewer
spruce.

More info for the terms: root crown, secondary colonizer

Tree without adventitious-bud root crown
Secondary colonizer - off-site seed

More info for the terms: epigeal, forest, litter, monoecious, seed, stratification

The major regeneration mode of Brewer spruce is by seed [2]. Brewer
spruce is monoecious and begins producing seed at 20 to 30 years of age.
Mature Brewer spruce are apparently fair seed producers [18]. Crops
occur at 2-year intervals, but some trees produce cones yearly [18].
Production of seed ranges between 51,000 and 74,000 seeds per pound
(112,500-163,000 seeds/kg) [18], with a reported average of 61,000 seeds
per pound (134,500 seeds/kg) [16]. Seeds of Brewer spruce require a
stratification period of 30 to 90 days [14,16]. Germinations rates vary
from 50 to 96 percent, with an average of 88 percent [16,18].

Germination is epigeal and occurs on loose soil from upturned roots,
decaying logs, forest humus, and leaf litter under brushfields.
Seedlings are unable to survive strong sunlight and are sensitive to
high moisture stress and temperatures of exposed sites. First season
epicotyl height growth is less than 0.24 inch (6 mm). Further growth is
slow, but it appears to be faster on south-facing montane chaparral
[18]. Saplings and pole-sized Brewer spruce average 6 inches (0.15 m)
in annual height growth [18].

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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):

1 Northern Pacific Border
4 Sierra Mountains

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More info for the terms: climax, competition

Brewer spruce is very shade tolerant and can become established under an
almost closed canopy [18,21]. It is usually occurs in late seral or
climax communities but can also invades seral pine stands and montane
chaparral [17,21]. Toward the eastern limit of its range, stands
dominated by western white pine (Pinus monticola) and Douglas-fir
(Pseudotsuga menziesii) are replace by Brewer spruce-Shasta red fir
(Abies magnifica var. shastensis) climax [21]. Brewer spruce is
restricted to less fertile soils because of strong competition from
other conifers [18,21].

The currently accepted scientific name of Brewer spruce is Picea
breweriana Wats. [14,18,19]. There are no recognized subspecies or
varieties. Brewer spruce grows adjacent to Engelmann spruce (Picea
engelmannii), but no hybridization between the two has been observed
[18].

The wood of Brewer spruce is soft, heavy, and close grained [14]. The
branching habit of Brewer spruce results in the wood having many knots,
and it has little commercial value. Trees that are harvested are often
mixed with other trees for use as low grade lumber [18].

Brewer spruce grows with a wide variety of associated plants and vegetation types in the montane and subalpine forests of the Klamath region. Although it grows throughout the region, its range is one of local, disjunct populations of various sizes. In some areas, it is an occasional climax tree species in mixed stands dominated by California red fir (Abies magnifica), white fir (A. concolor), or mountain hemlock (Tsuga mertensiana). In other areas, it grows in small, pure, dense stands on north-, east-, and west-facing slopes. It is also found as individuals invading seral pine stands and montane chaparral. In the Siskiyou Mountains' Brewer spruce seedlings and saplings are found in montane chaparral on all aspects. It is associated with Sadler oak Quercus sadleriana), huckleberry oak (Q. vaccinifolia), and greenleaf manzanita (Arctostaphylos patula).

Some of the best-developed stands of Brewer spruce are located on moderate east- and west-facing slopes with, deep soil. These forests in the California red fir/Sadler oak habitat have a 70 to 80 percent canopy cover. Density of trees over 10 cm (4 in) in d.b.h. is 125 to 320 Brewer spruce per hectare (50 to 130/acre), 30 to 95 white fir per hectare (12 to 39/acre), 10 to 70 Douglas-fir (Pseudotsuga menziesii) per hectare (4 to 28/acre), 0 to 10 sugar pine (Pinus lambertiana) per hectare (0 to 4/acre), and 5 to 60 California red fir per hectare (2 to 24/acre). The total basal area ranges from 35 to 54 m²/ha (153 to 235 ft²/acre),. Dense reproduction is present in the tolerant conifers: Brewer spruce, California red fir, and white fir; Brewer spruce has about one-third the total number of seedlings under 180 cm (70 in) in height.

Brewer spruce is an element of the following vegetation habitat types of the Klamath region (2,12,13,14). Plants of major importance are listed for each type.

Abies concolor zone, Siskiyou Mountains- Abies concolor/Vaccinium membranaceum (white fir/thinleaf huckleberry) habitat type. Brewer spruce is a minor climax species. Other shrubs: Sadler oak.

Abies concolor/Pachistima myrsinites (white fir/Oregon boxwood) habitat type. Brewer spruce is often a codominant climax species. Other trees: Douglas-fir and sugar pine. Other shrubs: Sadler oak, Oregongrape (Berberis nervosa). Other herbs: western prince's-pine (Chimaphila umbellata), rattlesnake plantain (Goodyera oblongifolia), and vanillaleaf (Achlys triphylla).

Chamaecyparis lawsoniana/Rhododendron occidentale (Port-Orford-cedar/western azalea) habitat type. Brewer spruce is often a minor climax species. Other trees: western white pine (Pinus monticola). Other shrubs: Sadler oak.

Abies concolor zone, central Klamath region- Abies concolor/Chimaphila umbellata (white fir/western prince's-pine) habitat type. Brewer spruce occasionally occurs as a minor climax species. Other trees: Douglas-fir, sugar pine, ponderosa pine (Pinus ponderosa), and incense-cedar (Libocedrus decurrens). Other shrubs: western hazel (Corylus cornuta), wood rose (Rosa gymnocarpa), and snowberry (Symphoricarpos hesperius).

Abies magnifica zone, Siskiyou Mountains- Abies magnifica/Quercus sadleriana (California red fir/Sadler oak) habitat type. Brewer spruce often occurs as a minor climax species. Other trees: white fir, Douglas-fir, western white pine, and sugar pine. Other shrubs: thinleaf huckleberry.

Abies magnifica/Arctostaphylos nevadensis (California red fir/pine mat manzanita) habitat type. Brewer spruce occasionally occurs as a codominant climax species. Other trees: western white pine. Other shrubs: Sadler Oak and greenleaf manzanita.

Picea breweriana/Quercus vaccinifolia (Brewer spruce/huckleberry oak) habitat type. Brewer spruce occurs as a codominant climax species. Other trees: western white pine, California red fir, Douglas-fir, and incense-cedar. Other shrubs: greenleaf manzanita, pine mat manzanita, and Sadler oak.

Picea breweriana/Quercus sadleriana (Brewer spruce/Sadler oak) habitat type. Brewer spruce occurs as the dominant climax species. Other trees: western white pine and white fir. Other shrubs: huckleberry oak and thinleaf huckleberry.

Abies magnifica zone, central and eastern Klamath region- Abies magnifica/Leucothoe davisiae (California red fir/mountain laurel) habitat type. Brewer spruce is an occasional minor climax species. Other trees: white fir, lodgepole pine (Pinus contorta), western white pine, and mountain hemlock (Tsuga mertensiana). Other shrubs: swamp current (Ribes lacustre), mountain alder (Alnus tenuifolia), and mountain ash (Sorbus californica). Other herbs: groundsel (Senecio triangularis), queenscup (Clintonia uniflora), starflower (Trientalis latifolia), trillium (Trillium ovatum), and false Solomon's seal (Smilacina stellata).

Abies magnifica/Linnaea borealis (California red fir/twinflower) habitat type. Brewer spruce is an occasional codominant climax species in open forest stands. Other trees: Douglas-fir, white fir, western white pine, mountain hemlock, sugar pine, ponderosa pine, western yew (Taxus brevifolia), incense-cedar, Engelmann spruce (Picea engelmannii), lodgepole pine, and subalpine fir (Abies lasiocarpa). Other shrubs: Sadler oak, wood rose, and snowberry. Other herbs: queenscup.

Abies magnifica/Quercus vaccinifolia (California red fir/huckleberry oak) habitat type. Brewer spruce is an occasional minor climax species. Other trees: white fir, Douglas-fir, sugar pine, lodgepole pine, and western white pine. Other shrubs: greenleaf manzanita, pine mat manzanita, and bush chinkapin (Castanopsis sempervirens).

Tsuga mertensiana zone, Siskiyou Mountains- Tsuga mertensiana/Vaccinium membranaceum (mountain hemlock/thinleaf huckleberry) habitat type. Brewer spruce is a codominant climax species. Other trees: California red fir, western white pine, and Alaska-cedar (Chamaecyparis nootkatensis).

Tsuga mertensiana zone, central and eastern Klamath region- Tsuga mertensiana/Phyllodoce empetriformis (western hemlock/heather) habitat type. Brewer spruce is an occasional codominant climax species. Other trees: California red fir, white fir, western white pine, and lodgepole pine. Other shrubs: Labrador-tea (Ledum glandulosum).

Tsuga mertensiana/Quercus vaccinifolia (western hemlock/huckleberry oak) habitat type. Brewer spruce is of minor importance as a climax species. Other trees: California red fir and western white pine. Other shrubs: pine mat manzanita, bush chinkapin, and greenleaf manzanita.

Brewer spruce is a minor component in three forest cover types (4): Mountain Hemlock (Society of American Foresters Type 205), Red Fir (Type 207), and California Mixed Subalpine (Type 256).

The range of Brewer spruce is primarily influenced by the maritime climate of the Pacific Ocean: cool, wet winters and warm, relatively dry summers. The climate changes drastically, however, from west to east across the range of Brewer spruce, which is 113 km (70 mi). On the most westerly ridge occupied by Brewer spruce, average annual precipitation is more than 2800 mm (110 in); farther east, it is less than 1000 mm (39 in). Most of the precipitation falls as winter rain or snow; less than 5 percent occurs in the summer. The amount of -snowfall and accumulated snowpack varies greatly from year to year and geographically across the range. A few stands of Brewer spruce in valleys receive no snow some years, whereas other stands accumulate up to 4 to 5 m (13 to 16 ft) (5). Humidity is high in the western part of the range and relatively low in the eastern part. Summer fog is common along the western-most ridges and valleys. Summer thunderstorms are common in the eastern portion of the range. Temperatures also vary widely. In the western portion, the mean temperature in January is 5° C (41° F); in July, 11° C (52° F). On the eastern edge of the range, the mean temperature is -1° C (30° F) in January and 20° C (68° F) in July.

The varied climate indicates that Brewer spruce has an ecological amplitude that should enable it to obtain a wider and more contiguous distribution. Its sensitivity to fire seems to have restricted its range (13).

The shallow root system of Brewer spruce makes it more susceptible than its associates to windthrow. In some areas, the high incidence of root rot (Heterobasidion annosum) further lowers its resistance to wind. Thin bark and long weeping branches make Brewer spruce susceptible to fire. Areas predictably occupied by Brewer spruce are limited to fire-resistant open forests on north-facing slopes or rocky ridges. A series of major forest fires in 1987 burned throughout the range of Brewer spruce. Most of the small, pure stands on north slopes were not damaged. In the more prevalent mixed stands, low-intensity ground fires killed the Brewer spruce and white fir, but the thick-barked Douglas-fir, pines, and California red fir survived. The recovery of Brewer spruce may take decades or centuries because of the extent of these fires. The increased potential of forest fires and inability of Brewer spruce seedlings to tolerate high moisture stress may result in its rapid extinction. If global warming occurs (11), it could threaten the existence of localized tree species such as Brewer spruce.

As a small tree, Brewer spruce has enough flexibility to bend under the weight of heavy snow. It develops a pistol butt as the tree matures.

Comparatively little damage from insects or fungi has been recorded for Brewer spruce (3). The Cooley spruce gall adelgid (Adelges cooleyi) is common but does little damage (6). Seed chalcids (Megastigmus spp.) have been observed in mature seeds. In some areas, 36 percent of the Brewer spruce was parasitized by the dwarfmistletoe Arceuthobium campylopodum (8). Brewer spruce is intolerant of industrial fumes.

Brewer spruce is monoecious. Strobilus buds form in early summer and develop in the fall. The dark purple male strobili are borne the following spring in axils of needles of the previous year's shoots, on branches throughout the tree. The pollen-bearing strobili are from 19 to 32 mm, (0.75 to 1.25 in) long and about 13 mm (0.5 in) in diameter. Pollen is shed in early summer; the male strobili dry and fall soon after pollen is shed. Female strobili are borne at the tips of primary branches in the upper two-thirds of the crown. They develop into erect, dark green, cylindrical conelets that are 38 mm (1.5 in) long and 13 mm (0.5 in) thick when receptive. The female conelets are apparently receptive at the time pollen is shed. The location of female and male flowers throughout the tree, concurrent with timing of strobilus development, apparently encourages selfing of Brewer spruce located singly or in small, isolated stands. After pollination, the conelets turn down and mature the same season into dark brown cones 8 to 15 cm (3 to 6 in) long. The fruit matures from September to October; dissemination immediately follows.

Little if any variability has been observed throughout the restricted range of Brewer spruce. In the eastern Klamath area, Brewer spruce grows adjacent to Engelmann spruce without hybridization (12).

After the seedling stage height growth of Brewer spruce is slower than its common associates, Douglas-fir, white fir, red fir, and western white pine. In several stands in the Siskiyou Mountains, annual height growth of sapling and pole-size Brewer spruce averaged 0.15 m (0.5 ft).

Most mature stands of Brewer spruce consist of a wide range of ages and sizes. Numerous stands contain Brewer spruce up to 117 cm (46 in) in diameter, the largest 125 cm (49.3 in) in d.b.h. and 48.8 m (160 ft) in height. The biggest Brewer spruce listed by the American Forestry Association (1) has a circumference of 4.17 m (13.67 ft) at 1.37 m (4.5 ft) above the ground and is 51.8 m (170 ft) tall; it is located in the Siskiyou National Forest in southwest Oregon. The general structure of a mixed species, all-aged stand (Sadler oak habitat type) is shown in table 1.

Table 1- Stand structure of mixed species, all-aged Brewer spruce stands (Sadler oak habitat type) Diameter class Brewer spruce White
fir Red
fir Douglas-
fir Western white pine Sugar
pine cm trees/ha 3 to 29 430 506 82 69 - - 30 to 59 114   32 27   2 7 - 60 to 89   17   15 15 - 2 - 90 to 119     2 -   7 - - - 120+ - -   2   2 - 2 in trees/acre 1 to 11 174 205 33 28 - - 12 to 23   46   13 11   1 3 - 24 to 35     7     6   6 - 1 - 35 to 47     1 -   3 - - - 47+ - -   1   1 - 1 Little volume or yield information is available for these Brewer spruce stands. The total basal area of the few stands sampled averages 47 m²/ha (205 ft²/acre), with a current annual increment of 2 m²/ha (9 ft²/acre) (15).

Brewer spruce is tolerant of shade at all ages and is very competitive. In the Abies magnifica zone on mesic to xeric sites, it is more competitive than mountain hemlock, Port-Orford-cedar, white fir, Douglas-fir, Alaska-cedar, incense-cedar, sugar pine, western white pine, ponderosa pine, lodgepole pine, and Jeffrey pine. California red fir is considered slightly more competitive on mesic sites because of its faster height growth and longer lifespan.

Brewer spruce is well adapted to growth at cool temperatures during the growing season. Its light compensation point is less than 2 percent of full sunlight. Brewer spruce can withstand considerable soil drought but is extremely sensitive to high evaporation demands. The stomata close under high evaporation, halting photosynthesis (17).

Brewer spruce is best managed on mesic sites characterized by the presence of Sadler oak. It grows best in mixed-species stands with uneven-aged management.

Brewer spruce can be planted under montane chaparral dominated by Sadler oak, huckleberry oak, and greenleaf manzanita. It has the ability to grow well under competition for soil moisture and light.

Brewer spruce has a shallow root system on all soils; however, on deeper soils, a few vertical roots may extend several meters in depth.

Seed production starts when the trees are from 20 to 30 years old. Actual production has not been determined. Observations indicate that mature Brewer spruce trees are fair seed producers; crops occur at 2-year intervals, and some trees produce cones each year.

The seeds are 3 to 5 mm (0.1 to 0.2 in) long; the wing is four times as long as the seed. The seeds are the largest of the North American spruces: 134,500/kg (61,000/lb), with a range of 112,500 to 163,000/kg (51,000 to 74,000/lb). The relatively large wing aids dissemination of the seed by the wind. Cones and seeds do not appear to be a preferred food for rodents.

Seeds may be stored for 5 to 17 years in sealed containers at low temperatures, 1° to 3° C (33° to 38° F), at a moisture content of 4 to 8 percent. A cold, moist stratification of 30 days increases germination. Germination of sound seed ranges from 50 to 96 percent; the reported average is 88 percent (15).

The germination of Brewer spruce is epigeal, seedlings becoming established on all types of natural seedbeds: decaying logs, forest humus, loose soil from upturned roots, and leaf litter under brush fields. Throughout the range of Brewer spruce, natural regeneration is abundant under dense Brewer spruce-white fir stands. These stands contain an average of 1,360 Brewer spruce and 3,460 white fir seedlings per hectare (550 and 1,400/acre) less than 15 cm (6 in) in height. Brewer spruce seedlings cannot survive strong sunlight. The shallow, slow-growing root system causes the seedlings to be susceptible to the high moisture stress and temperatures of exposed sites. Brewer spruce seedlings are usually lacking in clearcuts, even when these are adjacent to stands containing large cone bearing trees.

Seedlings are small, with four to seven cotyledons Initial growth is slow; the epicotyl height growth is less than 6 mm (0.24 in) the first season.

Subsequent growth of seedlings is slow but quite variable. Under dense stands, the age of seedling 1.37 m (4.5 ft) tall ranges from 27 to 82 years Brewer spruce seedlings growing in south-facing montane chaparral were from 25 to 40 years old when they were 1.37 m (4.5 ft) tall. Small Brewer spruce survive overstory removal.

Brewer spruce grows on a wide variety of geologic parent materials and soils. It is found on soils developed from sedimentary, granitic, serpentine, and metavolcanic rocks. Most of the large stands of Brewer spruce are found on shallow, rocky, undeveloped soils of the order Entisols; a few stands are on deeper, well-developed soils. Throughout its range, Brewer spruce is never found in areas where the soils are saturated during the growing season. It appears to be generally restricted from the more fertile soils by competition from true firs (Abies spp.). Brewer spruce is more abundant on less fertile soils.

Brewer spruce is found on most topographic locations-ridgetops, north- and south-facing slopes, benches, and valley bottoms. The only habitat restriction is boggy or wet areas. The apparently preferred location is the steep, north-facing slopes where the largest stands are located. In the western Siskiyou Mountains, these locations are north slopes near the tops of the ridges, but in the eastern Salmon Mountains, the largest stands are on middle, north-facing slopes. Brewer spruce is found from elevations of 700 to 2100 in (2,300 to 6,900 ft) in the western Siskiyou Mountains and from 1370 to 2290 in (4,500 to 7,500 ft) in the eastern Klamath region.

The wood of Brewer spruce has no special uses. Harvested trees are normally mixed with other species and utilized as low grade lumber. In Europe, it has been considered one of the most popular of all ornamental conifers (10).

Layering has no been observed in natural stands of Brewer spruce Artificial propagation is best from seed (10).

Pinaceae -- Pine family

Dale Thornburgh

Brewer spruce (Picea breweriana), named for its first collector, is often considered "mysterious" because this attractive conifer is found on seldom-visited high mountain ridges and steep north slopes. Its other common name, weeping spruce, is derived from the distinctive feature of many rope-like branchlets that hang in a fringe from all but the topmost slender horizontal limbs. This branching habit results in many knots in the wood, which has little commercial importance.

Brewer spruce is found only in the mountains of northwestern California and southwestern Oregon near the Pacific coast between latitudes 40° 50' N. and 42° 40' N. The best developed stands are on the high ridges of the western Siskiyou Mountains in California and Oregon. Other concentrations are found on high ridges and in upper valleys of the Marble, Salmon, and Trinity Mountains of California (7). Throughout the rest of the range, Brewer spruce grows as a single tree and as scattered small populations in valleys and on ridgetops (9,12,16).


- The native range of Brewer spruce

Tree, Evergreen, Monoecious, Habit erect, Trees without or rarely having knees, Tree with bark rough or scaly, Young shoots 3-dimensional, Buds resinous, Buds not resinous, Leaves needle-like, Leaves alternate, Needle-like leaf margins entire (use magnification), Leaf apex obtuse, Leaves < 5 cm long, Leaves < 10 cm long, Leaves not blue-green, Needle-like leaves flat, Needle-like leaves triangular, Needle-like leaves not twisted, Needle-like leaf habit erect, Needle-like leaf habit drooping, Needle-like leaves per fascicle mostly 1, Needle-like leaf sheath early deciduous, Needle-like leaf sheath persistent, Twigs pubescent, Twigs viscid, Twigs not viscid, Twigs with peg-like projections or large fascicles after needles fall, Berry-like cones orange, Woody seed cones > 5 cm long, Bracts of seed cone included, Seeds brown, Seeds winged, Seeds unequally winged, Seed wings prominent, Seed wings equal to or broader than body.

Picea breweriana, known as Brewer spruce, Brewer's weeping spruce, or weeping spruce, is a species of spruce native to western North America, where it is one of the rarest on the continent. The specific epithet breweriana is in honor of the American botanist William Henry Brewer.