VALUE AND USE
SPECIES: Picea pungens | Blue Spruce 



WOOD PRODUCTS VALUE : 
Blue spruce is not an important timber tree because it occurs
infrequently, and the wood is brittle with many knots [38,65].  The wood
is light, soft with numerous resin canals, close-grained, and weak
[104,122].  When it is harvested, it is often cut and marketed with
Engelmann spruce [77].


IMPORTANCE TO LIVESTOCK AND WILDLIFE : 
Blue spruce provides cover for a variety of bird and animal species
[29].  Big game forage is good throughout blue spruce habitat types in
northern New Mexico and southern Colorado [26].  Numerous birds eat blue
spruce seeds [122].  Blue spruce cones are cached by red squirrels in
Utah [128].

In a mixed-conifer forest in the White Mountains of Arizona, nongame
birds moderately preferred blue spruce for cover and gleening for
insects.  In a comparison of usage in logged and control areas, mountain
chickadee and ruby-crowned kinglet preferred blue spruce in unlogged
areas only; yellow-rumped warbler preferred it in both treatment areas;
and gray-headed junco preferred blue spruce in logged areas only [47].


PALATABILITY : 
Blue spruce is not a highly preferred food for either wildlife or
domestic animals [10,103].  Deer browse blue spruce infrequently [122].
In mixed-conifer forests, blue spruce is the least desired browse
species by elk and deer [67].  White-tailed deer in Conneticut browsed
ornamental blue spruce an average of 0.5 percent throughout the summer
[18].  Blue spruce can be used an an index of mule deer population size;
young blue spruce are severely damaged by browsing during times of
overpopulation [64].


NUTRITIONAL VALUE : 
The protein value of blue spruce is rated as poor, and its energy value
is fair [29].


COVER VALUE : 
Blue spruce provides good environmental protection for elk, mule deer,
white-tailed deer, small mammals, and small nongame and upland game
birds in Colorado, Utah, and Wyoming.  It gives poor cover for pronghorn
in Colorado and Wyoming, and fair to poor cover for waterfowl in Utah
and Wyoming [29].

Blue spruce was one of several species in a commercial conifer nursery
used by white-tailed and mule deer for hiding and thermal cover during a
severe winter in southeastern Wyoming [56].  Moose use blue spruce for
shelter [75].  In Wyoming, moose used the blue spruce climax association
an average of 5 percent over 4 years [63].  Where blue spruce occurred
in a ponderosa pine forest in Colorado, cavity nesting birds showed no
preference in tree species selection for nest sites [100].
Mixed-conifer forests of Arizona and New Mexico that blue spruce occur
in are valuable summer habitat for game and nongame animals and birds
[44,73].

Sensitive and endangered species use mixed-conifer stands in which blue
spruce occurs.  Such species include flammulated owls in Colorado, Jemez
Mountain salamander of New Mexico, and northern goshawks in Arizona
[20,94,98,99].  Bald eagle breeding areas at intermediate elevation in
Wyoming are dominated by blue spruce and narrowleaf cottonwood.  In the
Snake River Unit, 28 percent of the nests were in blue spruce trees
[114].


VALUE FOR REHABILITATION OF DISTURBED SITES : 
Blue spruce has been included in roadside reclamation on U.S. Highway 89
south of Afton, Wyoming.  One year after grasses had been planted,
container-grown blue spruce were planted [23].  Data on establishment
success were not given.

Blue spruce was chosen as one of several species to provide cover and
foraging area for wildlife.  This reclamation planting mediated habitat
loss due to increased water levels in Rufus Woods Lake, Washington [17].
No data on establishment success were given.

Blue spruce was planted in Canada as a part of shelterbelts to prevent
wind erosion [54].


OTHER USES AND VALUES : 
Blue spruce is planted extensively as an ornamental in North America and
Europe [13,77,104,].  Blue spruce are used as Christmas trees [38,65].
It is the state tree of Colorado and Utah [77,65].


MANAGEMENT CONSIDERATIONS : 
Silviculture:  Blue spruce has an intermediate tolerance for single-tree
selection harvesting [55].  Single-tree selection and diameter-limit
harvest methods were compared on a Southwestern old-growth mixed-conifer
stand in which blue spruce occurred.  The single-tree selection method
left the stand satisfactorily stocked with 54 percent damage to advance
regeneration.  Diameter-limit method left the stand understocked with 71
percent loss of advance regeneration [51].  Conifer regeneration by
small patch clearcutting was also recommended for these forests [42,52].
Effective seeding distance to obtain adequate natural regeneration of
blue spruce is about 3 to 4 times the height of the tree [80].  Because
blue spruce is considered a late successional species, it is not
suitable as a seed tree in clearcuts [53,106].  Silvicultural practices
for mixed-conifer stands are reviewed in detail [67].

Blue spruce ranged from 2 to 28 inches (5.1-71.1 cm) d.b.h. with most
trees at 2 inches (5.1 cm) in stand inventories of virgin mixed-conifer
forest; no blue spruce died during the 5 years of monitoring.  Initial
blue spruce volume was 360 board feet per acre; final volume was 391
board feet per acre.  Average annual growth of blue spruce was less than
0.2 inch (0.5 cm) [50].  In east-central Arizona, blue spruce were 3.05
square feet per acre (0.7 sq m/ha) basal area in a total 177.7 square
feet per acre (40.8 sq m/ha) for the mixed-conifer forest.  Blue spruce
annual basal growth of 2.9 percent was the highest growth rate for all
tree species present [33].  In blue spruce habitat series in central
Colorado, total basal areas ranged from 169 to 300 square feet per acre
(49-83 sq m/ha) with all size classes of blue spruce present [60,61].

Other Uses:  In wet sites with well-developed soil, blue spruce timber
potential is high; however, the timber value may be low.  Blue spruce is
often more valuable for wildlife habitat and food and for recreation
[70].

Blue spruce is a component of mixed-conifer forests that have been a
part of browse studies [41].  Equations exist for predicting forage
production [12,40,76].  Forage production estimates include hiding and
thermal cover for wildlife management.  Since these mixed-conifer
clearcuts require 50 to 100 years to regenerate, clearcut areas are a
long-term forage resource for deer and elk [118].  Quaking aspen
(Populus tremuloides) is often associated with blue spruce on upland
sites.  Treatment of conifers in these systems depends on whether aspen
is to be maintained for livestock forage or wildlife habitat [25].

Blue spruce is a part of mixed-conifer stands that are managed for
watershed [52].  Clearcuts in these forests increase water yield almost
in proportion to the area cleared [24].

Artificial vegetative propagation of blue spruce is possible using short
cuttings, grafting, and air layering [28,38,123].  Breeding commercial
stock has been successful; however, interspecific crosses rarely yield
viable hybrids [34,46,90,105].  Blue spruce pollen used in artificial
crosses is viable for almost 3 years when stored at cold temperatures
[36].  Methods for cone harvesting and seed extraction are discussed in
detail [32,103].

Blue spruce have been planted in a wide range of environments.  It has
been a part of state nursery programs to stock oldfields in Ohio [93].
Blue spruce nursery stock is more drought resistant than other spruce
species, and it can withstand temperatures to -40 degrees Fahrenheit
(-40 deg C) [38].  It can tolerate some flooding.  Forty percent of
3-year-old blue spruce seedlings survived 21 days under aerated,
submerged conditions; all died after 28 days [82].

Blue spruce was included in a 30-year shelterbelt project in the
northern Great Plains.  Blue spruce was 13 feet (4 m) tall at 20 years
with 32 percent of the original trees surviving [49].  It has been
successfully used in shelterbelts in Montana, North Dakota, and South
Dakota [9,119].  Planting recommendations have been discussed in detail
[4,107].

Damaging Agents:  Insects and disease reduce growth, viability, and
vigor of blue spruce [37,124].  Heart and root rots, cone rusts,
nematodes, snow molds, canker, and tip blight have an impact on blue
spruce [38,89].  Silvicultural methods that minimize pathologic and
insect problems are discussed in detail [2,45,106].  Calibrated
ecosystem models that correlate microclimate with blue spruce stand
information are useful for predicting the behavior of forest pathogens
[83].  Tree ring patterns of blue spruce have been used to construct
past occurrence of insect attacts [69].

Blue spruce is a host of western spruce budworm (Choristoneura
occidentalis); outbreaks and symptoms are discussed in detail [16,78].
Blue spruce is an infrequent host of mountain pine beetle (Dendroctonus
ponderosae) and spruce beetle (D. rufipennis), which kill other conifers
[5,62].  Trees surviving infestation are more susceptible to other
pathogens, insects, and windthrow [45,57].

Blue spruce is the principal host of western spruce dwarf mistletoe
(Arceuthobium microcarpum) and minor host of other dwarf mistletoe
species [58,59,124].  Infected blue spruce seedling mortality under a
heavily infested canopy was twice that of the control [79].

Related categories for Species: Picea pungens | Blue Spruce