Index of Species Information
SPECIES: Picea engelmannii
Introductory
SPECIES: Picea engelmannii
AUTHORSHIP AND CITATION :
Uchytil, Ronald J. 1991. Picea engelmannii. In: Fire Effects Information System, [Online].
U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station,
Fire Sciences Laboratory (Producer). Available:
https://www.fs.usda.gov/database/feis/plants/tree/piceng/all.html [].
ABBREVIATION :
PICENG
SYNONYMS :
Abies engelmannii Parry
Picea engelmannii var. glabra Goodman
Picea glauca var. engelmannii (Parry) Boivin
Picea glauca ssp. engelmannii (Parry) T. M. C. Taylor
Picea columbiana Lemmon
SCS PLANT CODE :
PIEN
COMMON NAMES :
Engelmann spruce
Columbian spruce
mountain spruce
TAXONOMY :
The genus Picea consists of about 30 species of evergreen trees found in
cool, temperate regions of the northern hemisphere. Seven species of
Picea, including Engelmann spruce, are native to North America. The
currently accepted scientific name of Engelmann spruce is Picea
engelmannii Parry ex Engelm. [45,53]. There are no recognized races or
geographic varieties.
Natural hybridization between species of Picea is common. Engelmann
spruce x white spruce (Picea glauca) hybrids are common where the ranges
of these species overlap. Natural crosses between these species occur
from central British Columbia as far south as eastern Washington and
Yellowstone National Park [23]. Within this area, trees at low
elevations closely resemble pure white spruce. Pure Engelmann spruce
tends to dominate at higher elevations [23]. Engelmann spruce x white
spruce hybrids are common throughout low elevations in British Columbia
[32].
Using artificial pollination techniques, Engelmann spruce has been
successfully crossed with white spruce, blue spruce (P. pungens), and
Sitka spruce (P. sitchensis) [32].
LIFE FORM :
Tree
FEDERAL LEGAL STATUS :
No special status
OTHER STATUS :
NO-ENTRY
DISTRIBUTION AND OCCURRENCE
SPECIES: Picea engelmannii
GENERAL DISTRIBUTION :
Engelmann spruce is widely distributed throughout the mountains of
the western United States and Canada. It occurs from central British
Columbia and Alberta as far south as New Mexico and Arizona [6]. It is
cultivated in Hawaii [101].
In the Pacific Coast region, Engelmann spruce is only a minor component
of high-elevation forests. It grows from the Coastal Range in
west-central British Columbia, south along the east slope of the
Cascades through Washington and Oregon to Mount Shasta in northern
California [6].
In the Rocky Mountains Engelmann spruce is a major component of
high-elevation forests. It grows from southwestern Alberta, south
through the mountains of eastern Washington, Idaho, and western Montana
to the high mountains of southern Arizona and New Mexico [6].
ECOSYSTEMS :
FRES20 Douglas-fir
FRES22 Western white pine
FRES23 Fir - spruce
FRES24 Hemlock - Sitka spruce
FRES25 Larch
FRES26 Lodgepole pine
FRES28 Western hardwoods
FRES44 Alpine
STATES :
AZ CA CO HI ID MT NV NM OR UT
WA WY AB BC
BLM PHYSIOGRAPHIC REGIONS :
2 Cascade Mountains
4 Sierra Mountains
5 Columbia Plateau
6 Upper Basin and Range
7 Lower Basin and Range
8 Northern Rocky Mountains
9 Middle Rocky Mountains
11 Southern Rocky Mountains
12 Colorado Plateau
16 Upper Missouri Basin and Broken Lands
KUCHLER PLANT ASSOCIATIONS :
K004 Fir - hemlock forest
K012 Douglas-fir forest
K014 Grand fir - Douglas-fir forest
K015 Western spruce - fir forest
K018 Pine - Douglas-fir forest
K020 Spruce - fir - Douglas-fir forest
K021 Southwestern spruce - fir forest
K052 Alpine meadows and barren
SAF COVER TYPES :
201 White spruce
203 Balsam poplar
205 Mountain hemlock
206 Engelmann spruce - subalpine fir
208 Whitebark pine
209 Bristlecone pine
210 Interior Douglas-fir
212 Western larch
213 Grand fir
215 Western white pine
216 Blue spruce
217 Aspen
218 Lodgepole pine
219 Limber pine
224 Western hemlock
226 Coastal true fir - hemlock
227 Western redcedar - western hemlock
228 Western redcedar
SRM (RANGELAND) COVER TYPES :
NO-ENTRY
HABITAT TYPES AND PLANT COMMUNITIES :
Climax stands consisting entirely of Engelmann spruce are somewhat
scattered and often restricted to wet or cold habitats [4,88]. The
Engelmann spruce series is generally recognized by the absence or scant
representation of subalpine fir. This is because many ecologists,
especially those working in the northern Rocky Mountains, believe that
only in the absence of subalpine fir does Engelmann spruce dominate at
climax [22,67,98].
Throughout the Rocky Mountains, Engelmann spruce occurs in widespread
forests within the subalpine fir or white fir (Abies concolor)
habitat-type series either as a climax codominant or long-lived seral
species [4,98]. In the northern Rocky Mountains, Engelmann spruce is
considered a long-lived seral species in fir habitat types. In the
central and southern Rocky Mountains, Engelmann spruce and subalpine fir
often codominate at climax; however, these forests are classified under
the subalpine fir series to be consistent with habitat-type usage
elsewhere [40,47].
Published classification schemes listing Engelmann spruce as an
indicator or dominant in habitat types (hts), community types (cts),
plant associations (pas), ecosystem associations (eas), site types
(sts), riparian zone associations (rzas), or dominance types (dts) are
presented below:
Area Classification Authority
AZ, NM: ----- forest & woodland hts Layser & Schubert 1979
----- forest hts Moir & Ludwig 1979
Apache, Gila,
Cibola NFs forest hts Fitzhugh & others 1987
s of Mogollon
n AZ: San Fransisco general veg. cts, hts Rominger & Paulik 1983
n AZ, n NM forest hts Larson & Moir 1987
CO: Arapaho &
Roosevelt NFs forest hts Hess & Alexander 1986
Gunnison &
Uncompahgre NFs forest hts Komarkova & others 1988
Routt NF forest hts Hoffman & Alexander 1980
White River NF forest hts Hoffman & Alexander 1983
w CO riparian pas Baker 1989a
ID: Sawtooth, White
Cloud, Boulder,
& Pioneer Mtns general veg. cts Schlatterer 1972
c ID forest hts Steele & others 1981
n ID forest hts Cooper & others 1987
e ID, w WY forest hts Steele & others 1983
riparian cts Youngblood & others 1985a
MT forest hts Pfister & others 1977
riparian dts Hansen & others 1988
c, e MT riparian cts, hts Hansen & others 1990
nw MT riparian hts, cts Boggs & others 1990
sw MT riparian sts, cts, hts Hansen & others 1989
NM: Cibola NF forest hts Alexander & others 1987
Lincoln NF forest hts Alexander & others 1984
n NM, s CO forest hts Develice & others 1986
OR: Wallowa-Whitman NF steppe & forest pas Johnson & Simon 1987
Deschutes, Ochoco,
Fremont &
Winema NF's riparian rzas Kovalchik 1987
OR, WA: Blue Mtns forest & nonforest cts Hall 1973
c, s UT forest hts Youngblood & Mauk 1985
n UT forest hts Mauk & Henderson 1984
UT, se ID riparian cts Padgett & others 1989
WA: Okanogan NF forest pas Williams & Lillybridge 1983
WY: ----- riparian cts Olson & Gerhart 1982
Medicine Bow NF forest hts Alexander & others 1986
Bighorn Mtns forest hts Hoffman & Alexander 1976
Wind River Mtns forest hts Reed 1976
USFS R-4 aspen cts Mueggler 1988
AB general veg. cts Moss 1955
w-c AB forest cts Corns 1983
general veg. eas Corns & Annas 1986
BC: Prince Rupert
Forest Region general veg. eas Pojar & others 1984
MANAGEMENT CONSIDERATIONS
SPECIES: Picea engelmannii
WOOD PRODUCTS VALUE :
Engelmann spruce is an important commercial wood in the United States.
The wood is white, odorless, lightweight, straight grained, soft, stiff,
and can be readily air dried. It is easy to work, glues well, holds
nails fairly well but has only average paint-holding properties. The
wood is primarily used for lumber for home construction and for
prefabricated wood products. Less common uses include veneer in plywood
manufacture, poles, and specialty items, such as food containers,
violins, pianos, and aircraft parts. Spruce has not been used much for
pulp and paper, although its pulping properties are excellent [6].
IMPORTANCE TO LIVESTOCK AND WILDLIFE :
Livestock: Livestock generally do not browse Engelmann spruce [4,89].
Wildlife habitat: Engelmann spruce-subalpine fir forests provide forage
and habitat for a wide variety of small and large wildlife species
[4,7,57,58]. However, these properties are characteristic of where
spruce grows and the understory species associated with it rather than
to the species itself. Animals that inhabit Engelmann spruce stands
include moose, elk, mule deer, woodland caribou, porcupine, snowshoe
hare, red squirrel, chipmunks, and voles. A partial list of birds that
nest and feed in Engelmann spruce trees includes the mountain chickadee,
Williamson's sapsucker, red-breasted nuthatch, brown creeper, and owls
and woodpeckers [82].
Wildlife food: The young growth of Engelmann spruce is occasionally
browsed by ungulates, but it is not an important food item and is
probably only taken as a last resort [4]. Spruce grouse and blue grouse
may feed extensively on buds and needles [56,80]. Squirrels sometimes
clip and eat twigs and buds [77].
Engelmann spruce seeds are eaten by several species of small mammals and
birds. Red squirrels, chickarees, and chipmunks eat seeds from cached
cones [6,98]. Engelmann spruce seeds are also eaten off the ground or
snow by chipmunks, mice, and voles [4]. Numerous species of birds,
including chickadees, nuthatches, crossbills, and the pine siskin,
remove and eat seeds from spruce cones [36,56]. Small birds may make
considerable use of spruce seeds, but their foraging is scattered and
sporadic throughout subalpine forests [36].
PALATABILITY :
The palatability of Engelmann spruce to livestock and big game is low
[26]. The seeds are palatable to small mammals and birds.
NUTRITIONAL VALUE :
Engelmann spruce is low in protein but fair in energy value [26]. A
study in Montana found the following concentration of elements in
Engelmann spruce needles and twigs [86]:
1-yr-old green needles twigs<.25 inch in diameter
Calcium (mg/g [mean]) 6809 4028
Copper 7 9
Iron 57 237
Potassium 6914 7034
Magnesium 810 747
Manganese 669 323
Nitrogen 10911 4621
Sodium 100 128
Phosphorus 1841 1264
Zinc 69 72
Ash (percent [mean]) 5 3
COVER VALUE :
Big game: Engelmann spruce provides excellent hiding and thermal cover
for deer, elk, moose, bighorn sheep, and bear [40,50,98]. Dense stands
of this species can provide cool summertime shade for big game.
High-elevation stands provide bedding sites and protection from storms
for bighorn sheep, mule deer, and elk [59].
Small mammals and birds: Small Engelmann spruce trees provide good
year-round hiding cover for small animals. Blue grouse, which
overwinter in conifers at high elevations, use spruce trees for
protective cover and roosting sites [50,80]. Spruce trees in the
Engelmann spruce/soft leaved sedge (Carex disperma) habitat type in
central Idaho provide important nesting sites for the MacGillivray's
warbler, American robin, and warbling vireo [89]. Engelmann spruce
snags are used by numerous cavity-nesting birds. Snags greater than 11
inches (28 cm) d.b.h. are most often used [82].
VALUE FOR REHABILITATION OF DISTURBED SITES :
Engelmann spruce can be planted on disturbed sites within forest
vegetation types where it naturally occurs. It is primarily used for
reforestation projects on cool, moist sites below upper timberline. It
has been used to a limited extent for revegetation and long-term
stabilization of high-elevation mine spoils [4,96]. In west-central
Alberta, Engelmann spruce x white spruce hybrids were observed invading
coal mine spoils at high elevations [76].
Planting nursery stock is more successful than direct seeding. Most
commonly, 2- or 3-year-old bareroot or container-grown stock is planted
following snowmelt [4,96]. Since seedlings are sensitive to direct
sunlight, they should be planted in the protective shade of stumps, logs,
or vegetation [4]. Artificial shade also is effective in protecting
seedlings from wind and sun [15]. Two- to 4-foot tall (0.6-1.5 m),
open-grown Engelmann spruce seedlings dug from the wild before breaking
dormancy have shown good survival when transplanted [15]. Methods for
collecting, processing, testing, storing, and planting seed, and for
care and transplanting of bareroot and container-grown Engelmann spruce
seedlings have been described in the literature [4,96].
OTHER USES AND VALUES :
Engelmann spruce is sometimes used as an ornamental landscape plant. It
has been used for screenings, windbreaks, and as a specimen tree [90].
Native Americans used Engelmann spruce for numerous purposes. The bark
was often peeled into sheets and used for making canoes, baskets, and
roofing. The fibrous roots were used to make rope, and the boughs and
needles to make incense, body scents, and cleansing agents. Various
teas and poultices were made from Engelmann spruce for medicinal
purposes. Native Americans occasionally ate the inner bark [92].
OTHER MANAGEMENT CONSIDERATIONS :
Timber harvest: Clearcutting and group selection silvicultural methods
favor Engelmann spruce over true firs (Abies) and hemlocks (Tsuga) but
increase the proportion of intolerant associates such as lodgepole pine
(Pinus contorta) and Douglas-fir (Pseudotsuga menziesii) [6].
Shelterwood and individual tree selection tend to favor more tolerant
associates. The seed tree method is generally not used because of the
susceptibility of Engelmann spruce to windthrow. In the Rocky
Mountains, clearcutting and shelterwood cutting have been the most
commonly used harvesting methods in old-growth Engelmann
spruce-subalpine fir stands because these stands tend to be even aged
and overmature [3]. Successful natural regeneration of Engelmann spruce
following logging is usually accomplished through mechanical
scarification or broadcast burns which expose at least 40 percent of the
mineral-soil seedbed [3]. Silvicultural systems and cutting methods for
managing Engelmann spruce are described in detail in the literature
[3,6].
Disease: The most common disease of Engelmann spruce is caused by
wood-rotting fungi which results in root or butt decay. Spruce broom
rust is also common in spruce-fir forests and causes bole deformation
and spike tops, increases susceptibility to wind breakage, and provides
entry points for decay fungi in spruce [7]. Dwarf mistletoe
(Arceuthobium microcarpum) causes heavy mortality of spruce trees in
Arizona and New Mexico [7].
Insects: The spruce beetle is the most serious insect pest of Engelmann
spruce. Outbreaks are associated with extensive windthrow because
downed trees provide a good food supply, causing a rapid expansion of
beetle populations. Unabated logging slash has been responsible for
past outbreaks [7].
BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Picea engelmannii
GENERAL BOTANICAL CHARACTERISTICS :
Engelmann spruce is a long-lived, native, coniferous, evergreen tree.
It is one of the largest of the high-elevation mountain conifers.
Mature trees have a narrow, pyramid form and short, compact branches.
Within natural stands, mature trees average 15 to 30 inches (38-76 cm)
in diameter; the average dominant height varies from 45 to 130 feet
(14-40 m), depending on site quality and density. Larger individuals
are not uncommon and may exceed 40 inches (102 cm) in diameter and 160
feet (49 m) in height. Engelmann spruce is long-lived; dominant trees
are often 350 to 450 years old, and 500- to 600-year-old trees are not
uncommon [7]. The crowns of trees within a stand normally make up 50 to
70 percent of the total height of the tree [4]. Dead lower limbs tend
to be persistent. The crowns of open-grown trees often extend down to
the ground. In alpine areas just above treeline, Engelmann spruce often
forms a krummholz. At treeline in northern Idaho, mature Engelmann
spruce generally do not exceed 65 feet (20 m) in height, and
progressively become more stunted as elevation increases, forming
krummholz at the most severe, high-elevation sites [17].
The four-sided, acute-tipped needles are not particularly sharp, are
deep bluish-green, and are 0.8 to 1.2 inches (2-3 cm) long [21,41]. The
young twigs are finely pubescent, a characteristic which differentiates
this spruce from white spruce, which has glabrous twigs. The bark is
very thin, grayish-brown on young trees but at maturity becomes purplish
brown to russet and is broken into loosely attached scales. Engelmann
spruce is generally shallow rooted, but laterals may penetrate to a
depth of 8 feet (2.4 m) in deep, porous, well-drained soils [4].
Engelmann spruce is monoecious. Female cones are light brown, 1.5 to
2.4 inches (4-6 cm) long, and occur in the upper part of the crown [21].
Male cones are usually found lower in the crown than female cones.
Engelmann spruce seeds are about 0.12 inch (3 mm) long and have a
single, well-developed wing about twice as long as the seed [21,77].
RAUNKIAER LIFE FORM :
Phanerophyte
REGENERATION PROCESSES :
Cone and seed production: Engelmann spruce can begin producing cones
when 15 to 40 years old and 4 or 5 feet (1.2-1.5 m) tall, but under
closed forest conditions seed production is generally not significant
until trees are older and taller [6]. Within natural stands, most seed
is produced by dominant trees greater than 15 inches (38 cm) d.b.h.
Although yearly production is erratic, Engelmann spruce is considered a
moderate to good seed producer. Good to bumper crops are produced every
2 to 5 years [4,6]. The seeds are light, averaging 135,000 per pound
(297,500/kg) [77].
Seed predation: Cone and seed insects, especially the spruce seed worm,
reduce seed yields. Seed production in Colorado was reduced an average
of 28 percent by insects over a 4-year period [4]. Small mammals
consume considerable amounts of freshly fallen seed off the forest
floor, but the extent of loss is not known [6].
Dispersal: Engelmann spruce seed is generally shed by the end of
October, but some may continue to fall throughout the winter. The
winged seeds are wind dispersed. Seeds travel primarily with the
prevailing winds, but upslope drafts can influence dispersal at low and
middle elevations. Seed is generally dispersed within 300 feet (91 m)
of a windward source; when bumper seed crops occur, about 5 to 10
percent of the seed may be dispersed as far as 600 feet (183 m) [6,63].
Seed dispersed during winter can travel great distances by skidding over
glazed snow [58].
Viability and germination: The viability of Engelmann spruce seed is
rated as good [7]. Germination averages 69 percent, which is much
higher than that of associated species [7,77]. Under natural
conditions, seeds overwinter under snow and germinate 2 to 3 weeks
following snowmelt [6,83]. Occasionally germination may occur after
summer rains or be delayed until the second year [4].
Seedling establishment and survival: Seedlings establish best on
mineral soil. Decayed wood, duff, and litter are poor seedbeds because
they dry out rapidly [6]. In general, seedlings that establish on
organic matter deeper than 2 inches (5 cm) soon die because their
shallow roots cannot penetrate to mineral soil before the surface
organic layer dries out [4]. At middle to upper elevations, seedling
survival may be greater on duff because the duff helps protect seedlings
from high-intensity summer rain storms and from frost heaving [29]. In
the central and southern Rocky Mountains, seedlings do not establish
well in the open. Intense light on open slopes can inhibit
photosynthesis, which eventually kills the seedling [63]. Direct
sunlight also dries out seedbeds. Seedlings survive best under
conditions of shade, cool temperatures, and adequate soil moisture [6].
Engelmann spruce requires a mineral soil seedbed; subalpine fir,
however, is able to establish in duff because of its rapid root growth.
Consequently, subalpine fir seedlings usually outnumber spruce seedlings
in the understory of spruce-fir stands, even where Engelmann spruce
dominates the overstory. Thus, even though it is short-lived, many
ecologists consider subalpine fir better able to regenerate under climax
conditions than Engelmann spruce.
Growth: Engelmann spruce seedlings grow very slowly. One-year-old
seedlings are seldom over 1 inch (2.5 cm) tall, and 5-year-old seedlings
are usually 1 to 4 inches (2.5-10 cm) tall. Ten-year-old seedlings may
be only 6 to 8 inches (15-20 cm) tall under heavy shade and 10 to 12
inches (25-30 cm) tall under partial shade. Under a dense overstory,
seedlings may be severely suppressed; 3- to 5-foot-tall trees may be 100
years old. In light shade or full sun trees may grow to 4 or 5 feet
(1.2-1.5 m) in height in about 20 years [6].
Vegetative reproduction: Near timberline, where the species assumes a
dwarf or prostrate form, Engelmann spruce frequently reproduces by
layering. Layering also occurs when only a few trees survive fire or
other disturbances, but once numbers have increased enough to improve
germination and establishment, layering decreases. In closed forest
stands layering is negligible [7].
SITE CHARACTERISTICS :
Engelmann spruce is found in some of the highest and coldest forest
environments in the western United States, characterized by long, cold
winters with heavy snowpack and short, cool summers [7]. It extends
down to lower elevations along stream bottoms where cold air flows down
the valley and collects in localized frost pockets [22]. It is
generally found on moist and cool sites, but at timberline it may occur
on somewhat dry sites. At middle elevations, pure stands are usually
found on alluvial terraces, wet benches, bottomlands, slopes with seeps
or cold north or east aspects [67,88]. It occurs on all aspects at
timberline.
Stand condition and associated conifers: Engelmann spruce forms pure
stands but is more commonly associated with subalpine fir. These
species frequently occur as codominants forming widespread subalpine
forests. In the central and southern Rocky Mountains, Engelmann spruce
commonly makes up 70 percent of overstory trees, and subalpine fir
dominates the understory. Within Engelmann spruce-subalpine fir forests
in this region, the spruce tends to be more important at higher
elevations and on wetter sites, while subalpine fir is more abundant on
drier lower elevation sites [4]. In Montana, pure Engelmann spruce
stands are often found in cool ravines at lower elevations than
subalpine fir [67]. Other associated conifers, which vary by latitude
and elevation, are listed below [6]:
Location Elevation Associates
northern Rocky Mtns low and western white pine (Pinus monticola),
and Cascade Mtns middle western redcedar (Thuja plicata),
western hemlock (Tsuga heterophylla),
Douglas-fir, grand fir (Abies grandis),
lodgepole pine
high Pacific silver fir (A. amabilis),
mountain hemlock (Tsuga mertensiana),
subalpine larch (Larix lyallii),
whitebark pine (Pinus albicaulis)
central and southern low and lodgepole pine, Douglas-fir, blue
Rocky Mtns middle spruce, white fir, aspen (Populus
tremuloides)
high corkbark fir (Abies lasiocarpa var.
arizonica), bristlecone pine (Pinus
aristata), limber pine (P. flexilis)
Understory associates: Understory vegetation is extremely variable,
changing with elevation, exposure, and soil moisture. Habitat type and
plant association guides describe characteristic understory plants for
differing sites.
Soil: Engelmann spruce grows best on moderately deep, well-drained,
loamy sands and silts, and silt and clay loam soils developed from
volcanic lava flows and sedimentary rock. It also grows well on
alluvial soils where the underlying water table is readily accessible.
It grows poorly on shallow, dry, coarse-textured sands; gravels
developed primarily from granitic and schistic rock; coarse sandstones
and conglomerates; rocky glacial till; heavy clay surface soils; and
saturated soils [6].
Elevation: Elevational ranges for Engelmann spruce are described below
[6]:
Cascade Mountains -- generally between 4,000 and 6,000 feet (1,219 and
1,829 m); at 8,000 feet (2,438 m) on sheltered
slopes and at 2,000 feet (610 m) in cold pockets
along streams and valley bottoms
Rocky Mountains:
ID, MT,
adjacent mtns
eastern WA and OR -- between 2,000 and 9,000 feet (610 and 2,743 m);
above 6,000 to 7,500 feet (1,829-2,286 m) a
minor component of the stand; below 5,000 feet
(1,676 m) confined to moist, lower slopes and
cold valley bottoms
UT, WY, and CO -- generally 9,000 to 11,000 feet (2,743-3,354 m); as
low as 8,000 feet (2,438 m) along cold stream bottoms
and sometimes as high as 11,500 (3,506 m)
AZ and NM;
plateaus of s UT -- between 8,000 and 12,000 feet (2,438 and 3,658 m);
most common between 9,500 and 11,000 feet (2,896
and 3,354 m)
SUCCESSIONAL STATUS :
In the Rocky Mountains north and south of Montana and Idaho, Engelmann
spruce and subalpine fir often codominate at climax to form extensive
Engelmann spruce-subalpine fir forests [4]. These spruce-fir forests
are usually classified as subalpine fir climax series habitat types. In
the understory of these stands, subalpine fir seedlings usually
outnumber Engelmann spruce seedlings because they are more shade
tolerant and readily establish on duff seedbeds. However, Engelmann
spruce is longer lived and usually the largest tree in the stand. There
is little evidence that Engelmann spruce will ever be replaced by
subalpine fir in these regions [47].
In the Rocky Mountains of Montana and Idaho, and in the mountains of
eastern Washington and eastern Oregon, Engelmann spruce is usually
considered seral to subalpine fir. Subalpine fir may form pure stands
at climax, but Engelmann spruce is also often present because it
outlives subalpine fir and persists to climax [4]. In eastern
Washington and northern Idaho, Engelmann spruce is seral to grand fir,
western redcedar, and western hemlock [22]. However, in Montana,
eastern and central Idaho, and western Wyoming, Engelmann spruce may
attain climax dominance on the wettest habitat types where it appears
more successful than subalpine fir [88]. Farther east, progressing away
from the Pacific maritime influence, the importance of Engelmann spruce
increases and that of subalpine fir decreases [88], and in parts of
central and southwestern Montana, Engelmann spruce may be dominant on
well-drained benches and droughty soils [67].
On sites where Engelmann spruce attains climax dominance or codominance,
succession following disturbance may vary depending on the severity and
type of disturbance, elevation, and availability of seed. Near
treeline, it may take 100 years or more for Engelmann spruce to
establish seedlings following fire because an increase in herbaceous
species prevents seeds from reaching mineral soil, and the harsh climate
kills many seedlings that do establish [12,85]. Within subalpine
stands, Engelmann spruce may establish immediately following disturbance
if mature trees survive to provide seeds, and seral species such as
lodgepole pine and aspen are scarce. Aspen and lodgepole pine are the
most common seral species and often dominate subalpine forests following
fire [6,47,85]. These species grow rapidly and quickly overtop any
Engelmann spruce seedlings that may establish at the same time. Aspen
stands can sometimes persist for decades or even centuries when conifer
seed trees are eliminated [25,89]. When lodgepole pine establishes
immediately following stand-destroying fires, it often forms dense
even-aged stands that dominate for 100 to 300 years. Because it is
shade tolerant, Engelmann spruce eventually establishes under the pine
canopy, usually within 100 years, and attains dominance as the pine
stand begins to break up [24,54].
On some of the lower elevation Engelmann spruce and subalpine fir
habitat types, Engelmann spruce will not achieve climax dominance or
codominance because of repeated fires which favor shade-intolerant seral
conifers. Many of these habitat types are in midsuccessional stages;
Douglas-fir, lodgepole pine, western larch (Larix occidentalis), or
limber pine dominate the overstory [67,88]
SEASONAL DEVELOPMENT :
Pollen is generally shed from late May to early June at lower elevations
and from late June to early July at higher elevations. Cones develop
rapidly and are full size by August. Cones open and seeds are shed in
late September and October, but some continue to fall throughout the
winter. After seed dispersal, most cones fall during the winter, but
some may persist for longer periods [4].
Phenological observations of Engelmann spruce in Montana, Idaho, and
Wyoming made from 1928 to 1937 are presented below [79]:
Buds Pollen shed Winter Cones Cones
burst begins ends buds formed full size open
(east of Continental Divide in Montana, and in Yellowstone NP)
avg date June 16 June 17 July 3 Aug 3 Aug 17 Aug 30
earliest May 21 May 18 May 30 June 26 July 19 Aug 18
latest July 14 July 3 July 20 Sept 17 Sept 5 Sept 21
(west of Continental Divide in western Montana and northern Idaho)
avg date May 27 June 1 June 7 Aug 23 Aug 6 Sept 8
earliest May 5 Apr 26 May 12 June 14 June 20 Aug 11
latest July 10 June 11 May 12? Oct 11 Sept 24 Oct 5
FIRE ECOLOGY
SPECIES: Picea engelmannii
FIRE ECOLOGY OR ADAPTATIONS :
Plant adaptations to fire: Engelmann spruce is very fire sensitive and
is generally killed even by low-intensity fires. Postfire
reestablishment is via wind-dispersed seeds which readily germinate on
fire-prepared seedbeds. The occasional mature tree which survives fire,
those escaping fire in small, unburned pockets, and trees adjacent to
burned areas provide seeds to colonize burned sites. Large trees
occasionally survive light fires [31].
Scattered individuals or pockets of Engelmann spruce trees commonly
escape burning because they occur in wet locations where fire spread is
hampered. In subalpine habitats, scattered Engelmann spruce trees often
escape fire because of discontinuous fuels, broken and rocky terrain,
and the moist and cool environment [67,88].
Fire regime: Engelmann spruce-subalpine fir forests usually develop in
cool, moist locations and experience fire-free intervals averaging 150
years or more [8]. Many Engelmann spruce stands are even aged,
suggesting that they developed after fire [54].
Fuels and fire behavior: The fuel structure in stands dominated by
Engelmann spruce and subalpine fir promotes highly destructive
stand-destroying fires. Fuel loads are higher than in lower elevation
montane stands, and the fuel beds tend to be irregular and have large
amounts of needle litter accumulating under the narrow crowned trees
[31,91]. The needles are small and fine, and form a compact fuel bed in
which fire spreads slowly [28]. These concentrated, slow-burning fuels
commonly produce flames high enough to reach Engelmann spruce's
low-growing, lichen-draped branches and start crown fires [20,91].
POSTFIRE REGENERATION STRATEGY :
crown-stored residual colonizer; short-viability seed in on-site cones
off-site colonizer; seed carried by wind; postfire years 1 and 2
secondary colonizer; off-site seed carried to site after year 2
FIRE EFFECTS
SPECIES: Picea engelmannii
IMMEDIATE FIRE EFFECT ON PLANT :
Engelmann spruce is easily killed by fire. It is very susceptible to
fire because it has (1) thin bark that provides little insulation for
the cambium, (2) a moderate amount of resin in the bark which ignites
readily, (3) shallow roots which are susceptible to soil heating, (4)
low-growing branches, (5) a tendency to grow in dense stands, (6)
moderately flammable foliage, and (7) heavy lichen growth [87].
Crown fires typically kill Engelmann spruce trees. Engelmann spruce is
also very susceptible to surface fires because fine fuels which are
often concentrated under mature trees burn slowly and girdle the
thin-barked bole or char the shallow roots [20,31]. Some large
Engelmann spruce may survive light, surface fires, but these often die
later due to infection by wood-rotting fungi that enter through fire
scars [31].
DISCUSSION AND QUALIFICATION OF FIRE EFFECT :
NO-ENTRY
PLANT RESPONSE TO FIRE :
Following fire, Engelmann spruce reestablishes via seeds dispersed by
wind from trees surviving in protected pockets or from trees adjacent to
burned areas. The rate of reestablishment is variable and depends on
the proximity of surviving cone-producing trees and seed production
during the year of the fire and immediate postfire years. In general,
Engelmann spruce seedling establishment is very slow in areas burned by
large, continuous crown fires because much of the seed source is
destroyed. However, on small burns or near pockets of surviving trees
within a large burn, Engelmann spruce usually establishes numerous
seedlings within 5 to 10 years [42,44].
In areas where Engelmann spruce is abundant and lodgepole pine scarce
before burning, Engelmann spruce establishes rapidly after fire if
sufficient numbers of seed trees survive or are near the burn. If
lodgepole pine is present in the preburn community, it usually seeds in
aggressively, assuming a dominant role as it overtops any spruce
seedlings establishing on the site [24,28,42]. However, Engelmann
spruce seedlings usually survive under the developing pine canopy
because of its shade tolerance.
Above 9,850 feet (3,000 m), lodgepole pine does not regenerate, and
burned areas remain open for several decades or longer. Postfire
succession in this harsh, high-elevation zone (9,850 to 10,850 feet
[3,000-3,300 m]) proceeds very slowly. Spruce slowly becomes
established as scattered seedlings [12]. It may take 100 to 200 years
before young spruce-fir forest covers the area. However, conditions in
the upper parts of this zone sometimes make it difficult for tree
seedlings to establish and survive at all. Here, grasses and sedges may
form a mat which prevents tree seeds from reaching mineral soil [85].
Burned fir-spruce forest is replaced by alpine tundra which can persist
for long periods of time [12].
DISCUSSION AND QUALIFICATION OF PLANT RESPONSE :
Postfire Engelmann spruce seedling establishment is best on moist
surfaces where fire has consumed most or all of the duff leaving bare
mineral soil. Seedlings do require some shade to survive; thus
regeneration after fire is best on sites where standing dead trees,
logs, or developing vegetation is present [73]. Engelmann spruce
postfire regeneration is poor on sites subjected to high light
intensities. A 26,000 acre (64,200 ha) burn on a high-elevation site in
southwestern Colorado showed poor conifer regeneration 100 years after
the fire. This was attributed to intense solar radiation which
inhibited photosynthesis, causing a high percentage of spruce seedlings
to die [75]. Postfire spruce regeneration is also poor where shrub and
herbaceous cover is dense, where exposed mineral soil is subject to
excessive evaporation, and where fire has only charred the duff [10].
Ash does not affect germination, but if it is deep, it can prevent a
seedling's roots from reaching mineral soil [62].
In northern Colorado, 3 years after a late August wildfire in a dense,
mature stand composed of Engelmann spruce, subalpine fir, and
lodgepole pine, Engelmann spruce established 1,000 seedlings per acre
(2,470/ha) in burned areas that were than less than 0.1 acre (0.05 ha).
However, in the middle of the main burn, no Engelmann spruce seedlings
had established by 3 years after the fire [10]. In Colorado, Peet [66]
reported a 75-year-old burn that had good spruce regeneration near the
burn boundary, but only 218 yards (200 m) inside the burn edge, few
seedlings had established, and the area was still fairly open.
Day [24] sampled lodgepole pine-Engelmann spruce x white spruce hybrid
stands in southern Alberta that had established after fires that had
occurred 29 and 56 years prior to sampling. He found that both pine and
spruce had initiated large numbers of seedlings immediately after the
fire. Pine, however, had established more seedlings and rapidly outgrew
the spruce, forming a canopy that was three to four times taller than
the spruce canopy. Pine seedling establishment had ceased by 30 years
after the fire, but spruce continued to establish seedlings. Engelmann
spruce eventually dominates sites where spruce and pine come in together
after fire.
The Research Project Summary Revegetation in a subalpine fir forest after logging
and fire in central British Columbia provides information on prescribed fire
and postfire response of plant community species, including Engelmann spruce,
that was not available when this species review was originally written.
FIRE MANAGEMENT CONSIDERATIONS :
After clearcutting Engelmann spruce stands, broadcast burning can be
used to prepare seedbeds for natural regeneration. Broadcast burns
which remove most of the duff or organic matter and burn hot enough to
destroy some or all of the competing vegetation favor spruce seedling
establishment [72]. However, seedling establishment is poor or
nonexistent in areas where hot fires leave deep layers of ash or
generate such intense heat that rocks are fractured, such as under slash
pile fires [72,94]. For this reason, where large amounts of slash must
be burned, windrows or piles should be kept small and cover a minimal
portion of the area [3]. Engelmann spruce often occurs in cool and
moist locations which restricts the time of year when effective
broadcast burning can take place. Prior to burning, duff must be dry
enough to ensure that it will be consumed. Seedling establishment will
be inhibited on burns that only blacken the organic matter. Some cull
logs and slash should be left in place to provide shade and protection
for developing seedlings [72].
Engelmann spruce stocking was greater than 50 percent and averaged 573
seedlings per acre (1415/ha) 5 years after broadcast burning in
clearcuts in northern Idaho where the uncut stand composition was 56
percent western larch, 22 percent Engelmann spruce, 15 percent mountain
hemlock, and 7 percent subalpine fir. This broadcast burn exposed
mineral soil on 53 percent of the area [14]. In northwestern Montana,
Engelmann spruce seedling establishment was much greater on broadcast
burned clearcuts where burning exposed mineral soil than on unburned
clearcuts. Eleven years after burning, stocking of Engelmann spruce
seedlings was 23 percent on burned cuts but only 1 percent on unburned
cuts. Seventeen years after burning, stocking was 56 percent on burned
cuts but only 2 percent on unburned cuts [84].
Broadcast burning is generally not recommended following partial cutting
because residual Engelmann spruce trees are very fire sensitive.
REFERENCES
SPECIES: Picea engelmannii
REFERENCES :
1. Alexander, Billy G., Jr.; Fitzhugh, E. Lee; Ronco, Frank, Jr.; Ludwig,
John A. 1987. A classification of forest habitat types of the northern
portion of the Cibola National Forest, New Mexico. Gen. Tech. Rep.
RM-143. Fort Collins, CO: U.S. Department of Agriculture, Forest
Service, Rocky Mountain Forest and Range Experiment Station. 35 p.
[4207]
2. Alexander, Billy G., Jr.; Ronco, Frank, Jr.; Fitzhugh, E. Lee; Ludwig,
John A. 1984. A classification of forest habitat types of the Lincoln
National Forest, New Mexico. Gen. Tech. Rep. RM-104. Fort Collins, CO:
U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest
and Range Experiment Station. 29 p. [300]
3. Alexander, Robert R. 1986. Silvicultural systems and cutting methods for
old-growth spruce-fir forests in the central and southern Rocky
Mountains. Gen. Tech. Rep. RM-126. Fort Collins, CO: U.S. Department of
Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment
Station. 33 p. [8221]
4. Alexander, Robert R. 1987. Ecology, silviculture, and management of the
Engelmann spruce-subalpine fir type in the central and southern Rocky
Mountains. Agric. Handb. 659. Washington, DC: U.S. Department of
Agriculture, Forest Service. 144 p. [8399]
5. Alexander, Robert R.; Hoffman, George R.; Wirsing, John M. 1986. Forest
vegetation of the Medicine Bow National Forest in southeastern Wyoming:
a habitat type classification. Res. Pap. RM-271. Fort Collins, CO: U.S.
Department of Agriculture, Forest Service, Rocky Mountain Forest and
Range Experiment Station. 39 p. [307]
6. Alexander, Robert R.; Shepperd, Wayne D. 1984. Silvical characteristics
of Engelmann spruce. Gen. Tech. Rep. RM-114. Fort Collins, CO: U.S.
Department of Agriculture, Forest Service, Rocky Mountain Forest and
Range Experiment Station. 38 p. [13310]
7. Alexander, Robert R.; Shepperd, Wayne D. 1990. Picea engelmannii Parry
ex Engelm. Engelmann spruce. In: Burns, Russell M.; Honkala, Barbara
H., technical coordinators. Silvics of North America. Volume 1.
Conifers. Agric. Handb. 654. Washington, DC: U.S. Department of
Agriculture, Forest Service: 187-203. [13384]
8. Arno, Stephen F. 1980. Forest fire history in the northern Rockies.
Journal of Forestry. 78(8): 460-465. [11990]
9. Baker, William L. 1989. Classification of the riparian vegetation of the
montane and subalpine zones in western Colorado. Great Basin Naturalist.
49(2): 214-228. [7985]
10. Barth, Richard C. 1970. Revegetation after a subalpine wildfire. Fort
Collins, CO: Colorado State University. 142 p. Thesis. [12458]
11. Bernard, Stephen R.; Brown, Kenneth F. 1977. Distribution of mammals,
reptiles, and amphibians by BLM physiographic regions and A.W. Kuchler's
associations for the eleven western states. Tech. Note 301. Denver, CO:
U.S. Department of the Interior, Bureau of Land Management. 169 p.
[434]
12. Dobrowolski, James P.; Ewing, Kern. 1990. Vegetation dynamics and
environmental attributes of a Great Basin valley exhibiting widespread
shrub dieback. In: McArthur, E. Durant; Romney, Evan M.; Smith, Stanley
D.; Tueller, Paul T., compilers. Proceedings--symposium on cheatgrass
invasion, shrub die-off, and other aspects of shrub biology and
management; 1989 April 5-7; Las Vegas, NV. Gen. Tech. Rep. INT-276.
Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain
Research Station: 103-114. [12842]
13. Boggs, Keith; Hansen, Paul; Pfister, Robert; Joy, John. 1990.
Classification and management of riparian and wetland sites in
northwestern Montana. Missoula, MT: University of Montana, School of
Forestry, Montana Forest and Conservation Experiment Station, Montana
Riparian Association. 217 p. Draft Version 1. [8447]
14. Boyd, R. J.; Deitschman, G. H. 1969. Site preparation aids natural
regeneration in western larch-Engelmann spruce strip clearcuttings. Res.
Pap. INT-64. Ogden, UT: U.S. Department of Agriculture, Forest Service,
Intermountain Forest and Range Experiment Station. 10 p. [7255]
15. Brown, J. A. 1974. Cultural practices for revegetation of high-altitude
disturbed lands. In: Berg, W. A.; Brown, J. A.; Cuany, R. L.,
co-chairmen. Proceedings of a workshop on revegetation of high-altitude
disturbed lands; 1974 January 31-February 1; Fort Collins, CO.
Information Series No. 10. Fort Collins, CO: Colorado State University,
Environmental Resources Center: 59-63. [7799]
16. Carlson, Clinton E.; Fellin, David G.; Schmidt, Wyman C. 1983. The
western spruce budworm in northern Rocky Mountain forests: a review of
ecology, past insecticidal treatments and silvicultural practices. In:
O'Loughlin, Jennifer; Pfister, Robert D., eds. Management of
second-growth forests: The state of knowledge and research needs:
Proceedings of a symposium; 1982 May 14; Missoula, MT. Missoula, MT:
University of Montana, School of Forestry, Montana Forest and
Conservation Experiment Station: 76-103. [7097]
17. Cooper, Stephen V.; Neiman, Kenneth E.; Steele, Robert; Roberts, David
W. 1987. Forest habitat types of northern Idaho: a second approximation.
Gen. Tech. Rep. INT-236. Ogden, UT: U.S. Department of Agriculture,
Forest Service, Intermountain Research Station. 135 p. [867]
18. Corns, I. G. W. 1983. Forest community types of west-central Alberta in
relation to selected environmental factors. Canadian Journal of Forest
Research. 13: 995-1010. [691]
19. Corns, I. G. W.; Annas, R. M. 1986. Field guide to forest ecosystems of
west-central Alberta. Edmonton, AB: Canadian Forestry Service, Northern
Forestry Centre. 251 p. [8998]
20. Crane, Marilyn F. 1982. Fire ecology of Rocky Mountain Region forest
habitat types. Final Report Contract No. 43-83X9-1-884. Missoula, MT:
U.S. Department of Agriculture, Forest Service, Region 1. 272 p. On file
with: U.S. Department of Agriculture, Forest Service, Intermountain
Research Station, Fire Sciences Laboratory, Missoula, MT. [5292]
21. Cronquist, Arthur; Holmgren, Arthur H.; Holmgren, Noel H.; Reveal, James
L. 1972. Intermountain flora: Vascular plants of the Intermountain West,
U.S.A. Vol. 1. New York: Hafner Publishing Company, Inc. 270 p. [717]
22. Daubenmire, R. 1969. Ecologic plant geography of the Pacific Northwest.
Madrono. 20: 111-128. [740]
23. Daubenmire, R. 1974. Taxonomic and ecologic relationships between Picea
glauca and Picea engelmannii. Canadian Journal of Botany. 52: 1545-1560.
[11039]
24. Day, Robert J. 1972. Stand structure, succession, and use of southern
Alberta's Rocky Mountain forest. Ecology. 53(3): 472-478. [12976]
25. DeVelice, Robert L.; Ludwig, John A.; Moir, William H.; Ronco, Frank,
Jr. 1986. A classification of forest habitat types of northern New
Mexico and southern Colorado. Gen. Tech. Rep. RM-131. Fort Collins, CO:
U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest
and Range Experiment Station. 59 p. [781]
26. Dittberner, Phillip L.; Olson, Michael R. 1983. The plant information
network (PIN) data base: Colorado, Montana, North Dakota, Utah, and
Wyoming. FWS/OBS-83/86. Washington, DC: U.S. Department of the Interior,
Fish and Wildlife Service. 786 p. [806]
27. Eyre, F. H., ed. 1980. Forest cover types of the United States and
Canada. Washington, DC: Society of American Foresters. 148 p. [905]
28. Fahnestock, George Reeder. 1977. Interactions of forest fire, flora, and
fuels in two Cascade Range wilderness Areas. Seattle, WA: University of
Washington. 179 p. Thesis. [10431]
29. Fiedler, Carl E.; McCaughey, Ward W.; Schmidt, Wyman C. 1985. Natural
regeneration in Intermountain spruce-fir forests--a gradual process.
Res. Pap. INT-343. Ogden, UT: U.S. Department of Agriculture, Forest
Service, Intermountain Forest and Range Experiment Station. 12 p.
[7482]
30. Fitzhugh, E. Lee; Moir, William H.; Ludwig, John A.; Ronco, Frank, Jr.
1987. Forest habitat types in the Apache, Gila, and part of the Cibola
National Forests, Arizona and New Mexico. Gen. Tech. Rep. RM-145. Fort
Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky
Mountain Forest and Range Experiment Station. 116 p. [4206]
31. Fischer, William C.; Bradley, Anne F. 1987. Fire ecology of western
Montana forest habitat types. Gen. Tech. Rep. INT-223. Ogden, UT: U.S.
Department of Agriculture, Forest Service, Intermountain Research
Station. 95 p. [633]
32. Fowler, D. P.; Roche, L. 1977. Genetics of Engelmann spruce. Res. Pap.
WO-30. Washington, DC: U.S. Department of Agriculture, Forest Service.
13 p. [7480]
33. Fryer, G. I.; Johnson E. A. 1988. Reconstructing fire behaviour and
effects in a subalpine forest. Journal of Applied Ecology. 25:
1063-1072. [10880]
34. Garrison, George A.; Bjugstad, Ardell J.; Duncan, Don A.; [and others].
1977. Vegetation and environmental features of forest and range
ecosystems. Agric. Handb. 475. Washington, DC: U.S. Department of
Agriculture, Forest Service. 68 p. [998]
35. Hall, Frederick C. 1973. Plant communities of the Blue Mountains in
eastern Oregon and southeastern Washington. R6-Area Guide 3-1. Portland,
OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest
Region. 82 p. [1059]
36. Halvorson, Curtis H. 1986. Influence of vertebrates on conifer seed
production. In: Shearer, Raymond C., compiler. Proceedings--conifer tree
seed in the Inland Mountain West symposium; 1985 August 5-6; Missoula,
MT. Gen. Tech. Rep. INT-203. Ogden, UT: U.S. Department of Agriculture,
Forest Service, Intermountain Research Station: 201-222. [12789]
37. Hansen, Paul; Boggs, Keith; Pfister, Robert; Joy, John. 1990.
Classification and management of riparian and wetland sites in central
and eastern Montana. Missoula, MT: University of Montana, School of
Forestry, Montana Forest and Conservation Experiment Station, Montana
Riparian Association. 279 p. [12477]
38. Hansen, Paul L.; Chadde, Steve W.; Pfister, Robert D. 1988. Riparian
dominance types of Montana. Misc. Publ. No. 49. Missoula, MT: University
of Montana, School of Forestry, Montana Forest and Conservation
Experiment Station. 411 p. [5660]
39. Hansen, Paul; Chadde, Steve; Pfister, Robert; [and others]. 1988.
Riparian site types, habitat types, and community types of southwestern
Montana. Missoula, MT: University of Montana, School of Forestry,
Montana Riparian Association. 140 p. [5883]
40. Hess, Karl; Alexander, Robert R. 1986. Forest vegetation of the Arapaho
and Roosevelt National Forests in central Colorado: a habitat type
classification. Res. Pap. RM-266. Fort Collins, CO: U.S. Department of
Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment
Station. 48 p. [1141]
41. Hitchcock, C. Leo; Cronquist, Arthur; Ownbey, Marion. 1969. Vascular
plants of the Pacific Northwest. Part 1: Vascular cryptograms,
gymnosperms, and monocotyledons. Seattle, WA: University of Washington
Press. 914 p. [1169]
42. Horton, K. W. 1956. The ecology of lodgepole pine in Alberta and its
role in forest succession. Tech. Note No. 45. Ottawa, Canada: Department
of Northern Affairs and National Resources, Forestry Branch, Forest
Research Division. 29 p. [13734]
43. Johnson, Charles G., Jr.; Simon, Steven A. 1987. Plant associations of
the Wallowa-Snake Province: Wallowa-Whitman National Forest.
R6-ECOL-TP-255A-86. Baker, OR: U.S. Department of Agriculture, Forest
Service, Pacific Northwest Region, Wallowa-Whitman National Forest. 399
p. [9600]
44. Johnson, E. A.; Fryer, G. I. 1989. Population dynamics in lodgepole
pine--Engelmann spruce forests. Ecology. 70(5): 1335-1345. [9303]
45. Kartesz, John T.; Kartesz, Rosemarie. 1980. A synonymized checklist of
the vascular flora of the United States, Canada, and Greenland. Volume
II: The biota of North America. Chapel Hill, NC: The University of North
Carolina Press; in confederation with Anne H. Lindsey and C. Richie
Bell, North Carolina Botanical Garden. 500 p. [6954]
46. Knapp, Alan K.; Smith, William K. 1982. Factors influencing understory
seedling establishment of Engelmann spruce and subalpine fir in
southeast Wyoming. Canadian Journal of Botany. 60(753): 2753-2761.
[12913]
47. Komarkova, Vera; Alexander, Robert R.; Johnston, Barry C. 1988. Forest
vegetation of the Gunnison and parts of the Uncompahgre National
Forests: a preliminary habitat type classification. Gen. Tech. Rep.
RM-163. Fort Collins, CO: U.S. Department of Agriculture, Forest
Service, Rocky Mountain Forest and Range Experiment Station. 65 p.
[5798]
48. Kovalchik, Bernard L. 1987. Riparian zone associations: Deschutes,
Ochoco, Fremont, and Winema National Forests. R6 ECOL TP-279-87.
Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific
Northwest Region. 171 p. [9632]
59. Kuchler, A. W. 1964. Manual to accompany the map of potential vegetation
of the conterminous United States. Special Publication No. 36. New York:
American Geographical Society. 77 p. [1384]
50. Lamb, S. H. 1971. Woody plants of New Mexico and their value to
wildlife. Bull. 14. Albuquerque, NM: New Mexico Department of Game and
Fish. 80 p. [9818]
51. Larson, Milo; Moir, W. H. 1987. Forest and woodland habitat types (plant
associations) of northern New Mexico and northern Arizona. 2d ed.
Albuquerque, NM: U.S. Department of Agriculture, Forest Service,
Southwestern Region. 90 p. [8947]
52. Layser, Earle F.; Schubert, Gilbert H. 1979. Preliminary classification
for the coniferous forest and woodland series of Arizona and New Mexico.
Res. Pap. RM-208. Fort Collins, CO: U.S. Department of Agriculture,
Forest Service, Rocky Mountain Forest and Range Experiment Station. 27
p. [1428]
53. Little, Elbert L., Jr. 1979. Checklist of United States trees (native
and naturalized). Agric. Handb. 541. Washington, DC: U.S. Department of
Agriculture, Forest Service. 375 p. [2952]
54. Loope, Lloyd L.; Gruell, George E. 1973. The ecological role of fire in
the Jackson Hole area, northwestern Wyoming. Quaternary Research. 3:
425-443. [1472]
55. Lyon, L. Jack; Stickney, Peter F. 1976. Early vegetal succession
following large northern Rocky Mountain wildfires. In: Proceedings, Tall
Timbers fire ecology conference and Intermountain Fire Research Council
fire and land management symposium; 1974 October 8-10; Missoula, MT. No.
14. Tallahassee, FL: Tall Timbers Research Station: 355-373. [1496]
56. Martin, Alexander C.; Zim, Herbert S.; Nelson, Arnold L. 1951. American
wildlife and plants. New York: McGraw-Hill Book Company, Inc. 500 p.
[4021]
57. Mauk, Ronald L.; Henderson, Jan A. 1984. Coniferous forest habitat types
of northern Utah. Gen. Tech. Rep. INT-170. Ogden, UT: U.S. Department of
Agriculture, Forest Service, Intermountain Forest and Range Experiment
Station. 89 p. [1553]
58. McCaughey, Ward W.; Schmidt, Wyman C.; Shearer, Raymond C. 1986.
Seed-dispersal characteristics of conifers. In: Shearer, Raymond C.,
compiler. Proceedings--conifer tree seed in the Inland Mountain West
symposium; 1985 August 5-6; Missoula, MT. Gen. Tech. Rep. INT-203.
Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain
Research Station: 50-62. [12593]
59. Moir, William H.; Ludwig, John A. 1979. A classification of spruce-fir
and mixed conifer habitat types of Arizona and New Mexico. Res. Pap.
RM-207. Fort Collins, CO: U.S. Department of Agriculture, Forest
Service, Rocky Mountain Forest and Range Experiment Station. 47 p.
[1677]
60. Moss, E. H. 1959. Flora of Alberta. Toronto: University of Toronto
Press. 546 p. [8948]
61. Mueggler, Walter F. 1988. Aspen community types of the Intermountain
Region. Gen. Tech. Rep. INT-250. Ogden, UT: U.S. Department of
Agriculture, Forest Service, Intermountain Research Station. 135 p.
[5902]
62. Muri, Glen. 1955. The effect of simulated slash burning on germination,
primary survival and top-root ratios of Engelmann spruce and alpine fir.
Res. Note. 14. Vancouver, BC: University of British Columbia, Forest
Club. 7 p. [4027]
63. Noble, Daniel L.; Ronco, Frank, Jr. 1978. Seedfall and establishment of
Engelmann spruce and subalpine fir in clearcut openings in Colorado.
RM-200. Fort Collins, CO: U.S. Department of Agriculture, Forest
Service, Rocky Mountain Forest and Range Experiment Station. 12 p.
[7481]
64. Olson, R. A.; Gerhart, W. A. 1982. A physical and biological
characterization of riparian habitat and its importance to wildlife in
Wyoming. Cheyenne, WY: Wyoming Game and Fish Department. 188 p. [6755]
65. Padgett, Wayne G.; Youngblood, Andrew P.; Winward, Alma H. 1989.
Riparian community type classification of Utah and southeastern Idaho.
R4-Ecol-89-01. Ogden, UT: U.S. Department of Agriculture, Forest
Service, Intermountain Region. 191 p. [11360]
66. Peet, Robert K. 1981. Forest vegetation of the Colorado Front Range:
composition and dynamics. Vegetatio. 45: 3-75; 1981. [1867]
67. Pfister, Robert D.; Kovalchik, Bernard L.; Arno, Stephen F.; Presby,
Richard C. 1977. Forest habitat types of Montana. Gen. Tech. Rep.
INT-34. Ogden, UT: U.S. Department of Agriculture, Forest Service,
Intermountain Forest and Range Experiment Station. 174 p. [1878]
68. Pojar, J.; Trowbridge, R.; Coates, D. 1984. Ecosystem classification and
interpretation of the sub-boreal spruce zone, Prince Rupert Forest
Region, British Columbia. Land Management Report No. 17. Victoria, BC:
Province of British Columbia, Ministry of Forests. 319 p. [6929]
79. Ramotnik, Cynthia A.; Scott, Norman J., Jr. 1988. Habitat requirements
of New Mexico's endangered salamanders. In: Szaro, Robert C.; Severson,
Kieth E.; Patton, David R., technical coordinators. Management of
amphibians, reptiles, and small mammals in North America: Proceedings of
the symposium; 1988 July 19-21; Flagstaff, AZ. Gen. Tech. Rep. RM-166.
Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky
Mountain Forest and Range Experiment Station: 54-63. [7108]
70. Raunkiaer, C. 1934. The life forms of plants and statistical plant
geography. Oxford: Clarendon Press. 632 p. [2843]
71. Reed, Robert M. 1976. Coniferous forest habitat types of the Wind River
Mountains, Wyoming. American Midland Naturalist. 95(1): 159-173. [1950]
72. Roe, Arthur L.; Alexander, Robert R.; Andrews, Milton D. 1970. Engelmann
spruce regeneration practices in the Rocky Mountains. Production
Research Report No. 115. Washington, DC: U.S. Department of Agriculture,
Forest Service. 32 p. [8215]
73. Roe, Arthur L.; Beufait, William R.; Lyon, L. Jack; Oltman, Jerry L.
1971. Fire and forestry in the northern Rocky Mountains--a task force
report. Journal of Forestry. 68(8): 465-470. [7265]
74. Rominger, James M.; Paulik, Laurie A. 1983. A floristic inventory of the
plant communities of the San Francisco Peaks Research Natural Area. Gen.
Tech. Rep. RM-96. Fort Collins, CO: U.S. Department of Agriculture,
Forest Service, Rocky Mountain Forest and Range Experiment Station. 9 p.
[2023]
75. Ronco, Frank. 1975. Diagnosis: "sunburned" trees. Journal of Forestry.
January: 31-35. [8241]
76. Russell, W. B. 1985. Vascular flora of abandoned coal-mined land, Rocky
Mountain Foothills, Alberta. Canadian Field-Naturalist. 99(4): 503-516.
[10461]
77. Safford, L. O. 1974. Picea A. Dietr. spruce. In: Schopmeyer, C. S., ed.
Seeds of woody plants in the United States. Agric. Handb. 450.
Washington, DC: U.S. Department of Agriculture, Forest Service: 587-597.
[7728]
78. Schlatterer, Edward F. 1972. A preliminary description of plant
communities found on the Sawtooth, White Cloud, Boulder and Pioneer
Mountains. Unpublished report. Ogden, UT: U.S. Department of
Agriculture, Forest Service, Intermountain Region. 111 p. [2076]
79. Schmidt, Wyman C.; Lotan, James E. 1980. Phenology of common forest
flora of the northern Rockies--1928 to 1937. Res. Pap. INT-259. Ogden,
UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest
and Range Experiment Station. 20 p. [2082]
80. Schroeder, Richard L. 1984. Habitat suitability index models: blue
grouse. FWS/OBS-82/10.81. Washington, DC: U.S. Department of the
Interior, Fish and Wildlife Service. 19 p. [11718]
81. Scott, Virgil E.; Crouch, Glenn L.; Whelan, Jill A. 1982. Responses of
birds and small mammals to clearcutting in a subalpine forest in central
Colorado. Res. Note RM-422. Fort Collins, CO: U.S. Department of
Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment
Station. 6 p. [4494]
82. Scott, Virgil E.; Whelan, Jill A.; Alexander Robert R. 1978. Dead trees
used by cavity-nesting birds on the Fraser Experimental Forest: a case
history. Res. Note RM-422. Fort Collins, CO: U.S. Department of
Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment
Station. 6 p. [4539]
83. Shearer, Raymond C. 1984. Effects of prescribed burning and wildfire on
regeneration in a larch forest in northwest Montana. In: New forests for
a changing world; Proceedings, Society of American Foresters convention;
1983; Portland, OR. Washington, DC: Society of American Foresters:
266-270. [6730]
84. Shearer, Raymond C. 1989. Fire effects on natural conifer regeneration
in western Montana. In: Baumgartner, David M.; Breuer, David W.; Zamora,
Benjamin A.; [and others], compilers. Prescribed fire in the
Intermountain region: Symposium proceedings; 1986 March 3-5; Spokane,
WA. Pullman, WA: Washington State University, Cooperative Extension:
19-33. [11242]
85. Stahelin, R. 1943. Factors influencing the natural restocking of high
altitude burns by coniferous trees in the central Rocky Mountains.
Ecology. 24(1): 19-30. [12910]
86. Stark, N. 1983. The nutrient content of Rocky Mountain vegetation: a
handbook for estimating nutrients lost through harvest and burning.
Misc. Publ. 14. Missoula, MT: University of Montana, School of Forestry,
Montana Forest and Conservation Experiment Station. 81 p. [8617]
87. Starker, T. J. 1934. Fire resistance in the forest. Journal of Forestry.
32: 462-467. [82]
88. Steele, Robert; Cooper, Stephen V.; Ondov, David M.; [and others]. 1983.
Forest habitat types of eastern Idaho-western Wyoming. Gen. Tech. Rep.
INT-144. Ogden, UT: U.S. Department of Agriculture, Forest Service,
Intermountain Forest and Range Experiment Station. 122 p. [2230]
89. Steele, Robert; Pfister, Robert D.; Ryker, Russell A.; Kittams, Jay A.
1981. Forest habitat types of central Idaho. Gen. Tech. Rep. INT-114.
Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain
Forest and Range Experiment Station. 138 p. [2231]
90. Sutton, Richard F.; Johnson, Craig W. 1974. Landscape plants from Utah's
mountains. EC-368. Logan, UT: Utah State University, Cooperative
Extension Service. 135 p. [49]
91. Taylor, K. L.; Fonda, R. W. 1990. Woody fuel structure and fire in
subalpine fir forests, Olympic National Park, Washington. Canadian
Journal of Forestry Research. 20: 193-199. [11518]
92. Turner, Nancy J. 1988. Ethnobotany of coniferous trees in Thompson and
Lillooet Interior Salish of British Columbia. Economic Botany. 42(2):
177-194. [4542]
93. U.S. Department of Agriculture, Soil Conservation Service. 1982.
National list of scientific plant names. Vol. 1. List of plant names.
SCS-TP-159. Washington, DC. 416 p. [11573]
94. Vogl, Richard J.; Ryder, Calvin. 1969. Effects of slash burning on
conifer reproduction in Montana's Mission Range. Northwest Science.
43(3): 135-147. [8546]
95. Volland, Leonard A. 1985. Plant associations of the central Oregon
Pumice Zone. Rt-ECOL-104-1985. Portland, OR: U.S. Department of
Agriculture, Forest Service, Pacific Northwest Region. 138 p. [7341]
96. Wasser, Clinton H. 1982. Ecology and culture of selected species useful
in revegetating disturbed lands in the West. FWS/OBS-82/56. Washington,
DC: U.S. Department of the Interior, Fish and Wildlife Service, Office
of Biological Services, Western Energy and Land Use Team. 347 p.
Available from NTIS, Springfield, VA 22161; PB-83-167023. [2458]
97. Williams, Clinton K.; Lillybridge, Terry R. 1983. Forested plant
associations of the Okanogan National Forest. R6-Ecol-132b. Portland,
OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest
Region. 116 p. [2566]
98. Youngblood, Andrew P.; Mauk, Ronald L. 1985. Coniferous forest habitat
types of central and southern Utah. Gen. Tech. Rep. INT-187. Ogden, UT:
U.S. Department of Agriculture, Forest Service, Intermountain Research
Station. 89 p. [2684]
99. Youngblood, Andrew P.; Padgett, Wayne G.; Winward, Alma H. 1985.
Riparian community type classification of eastern Idaho - western
Wyoming. R4-Ecol-85-01. Ogden, UT: U.S. Department of Agriculture,
Forest Service, Intermountain Region. 78 p. [2686]
100. Stickney, Peter F. 1989. Seral origin of species originating in northern
Rocky Mountain forests. Unpublished draft on file at: U.S. Department of
Agriculture, Forest Service, Intermountain Research Station, Fire
Sciences Laboratory, Missoula, MT; RWU 4403 files. 7 p. [20090]
101. St. John, Harold. 1973. List and summary of the flowering plants in the
Hawaiian islands. Hong Kong: Cathay Press Limited. 519 p. [25354]
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