VALUE AND USE
SPECIES: Abies amabilis | Pacific Silver Fir 



WOOD PRODUCTS VALUE : 
The wood of Pacific silver fir is soft, light in weight and color, and
has little odor or resin [14,26].  The wood is weak and has low
durability [26].  The most common uses of Pacific silver fir are light
construction frames, subfloor, construction plywood, sheaths, container
veneer, and pulpwood [14,24,26].  As a "white wood", Pacific silver fir
is a major export to Japan for business construction [24].  It is used
for Christmas trees and decorative greenery [14,24,26].


IMPORTANCE TO LIVESTOCK AND WILDLIFE : 
Old-growth stands provide good mountain goat habitat [70].  Northern
spotted owls are dependent on the availability of old-growth stands for
nest site selection and sufficient prey [54].  Other species with a
preference for old-growth stands include Vaux's swift, fisher, western
red-backed vole, and Olympic salamander [60].  Small nongame birds
prefer late seral or old-growth Pacific silver fir stands [39].

The seeds of Pacific silver fir are eaten by birds, rodents, and
squirrels [59,63].  Pacific silver fir is the least preferred of trees
browsed by elk [33].


PALATABILITY : 
NO-ENTRY


NUTRITIONAL VALUE : 
NO-ENTRY


COVER VALUE : 
The dense growth of Pacific silver fir provides hiding, cover, and
thermal protection for wildlife [22].


VALUE FOR REHABILITATION OF DISTURBED SITES : 
Pacific silver fir is a good choice among tree species for planting in
watersheds and locations with large amounts of mountain snowpack
[22,24,26,41].  It is also well suited for developments such as
campgrounds and trails [28].


OTHER USES AND VALUES : 
Pacific silver fir is grown as an ornamental [51].  It is a major
component of recreational and wilderness areas [14].


MANAGEMENT CONSIDERATIONS : 
Rotation periods for Pacific silver fir vary, depending on management
objectives.  For mountain goat habitat, the recommended rotation period
is 90 to 110 years [70].  For other nontimber (i.e. recreational, etc.)
benefits, the suggested rotation period is 150 to 200 years.  Commercial
rotations are seldom longer than 110 years [70].  After release by
logging or windfall, suppressed trees respond with immediate and
substantial growth [59].  At lower elevations in the Pacific silver fir
zone, Pacific silver fir usually sun scalds when used as leave tree in
shelterwood cuttings [26].  Sudden exposure to sunlight temporarily
reduces growth.  By the third season, the exposed trees are growing
faster than those trees at the stand edge.  As many as seven growing
seasons may be needed for Pacific silver fir to reach maximum rates of
branch and height growth [65].  The shade tolerance of Pacific silver
fir makes it a good choice for the selection method.  The disadvantage
of this practice is that it appears to encourage disease [36].

The timing of cone collection (mid to late August) is important because
cones disintegrate as they mature.  Felling and topping are not
successful collection methods.  The cones are susceptible to molding and
heat build-up if sacked when wet [18].  Calcid flies (Pregastigmus spp.)
infect cones of Pacific silver fir [59].  Franklin [24] discusses a cone
drying schedule and seed storage conditions.  Seeds are delicate and
their coats may be damaged when drying [16].  Edwards [17] reviews
techniques of seed extraction, viability, and germination testing.
Cleaned seeds range from 17,200 to 45,860 seeds per pound (7,800-20,800
seeds/kg) [14], and average 11,000 to 13,800 seeds per pound
(4,590-6,210 seeds/kg) [24].  A stratification period of 21 to 28 days
is required.  Seeds should be sown in spring at a density of 62.5 to 125
per acre (25-50 per ha) and approximately 0.25 inch (0.64 cm) deep,
depending on the site [24].  Arnott and Mathews [7] discuss nursery
practice for Pacific silver fir.  Highest stocking can be achieved on
bare soil [34].  Seedlings planted in logged areas have done poorly [6].

Gessel and Klock [31] report that fertilizer contributes significantly
to growth of Pacific silver fir on poor sites, but Packee and others
[51] disagree.  During the seedling stage when growth is slow,
fertilizer may be more effective than during other stages [52].  The
application of nitrates are more beneficial to Pacific silver fir than
ammonia compounds [31,42,51].  Fertilizer combined with thinning results
in accelerated volume and radial growth [31].

Herbicides have various effects on Pacific silver fir.  The effect of
glyphosate and granular and liquid hexazinone had little effect.  2,4-D
ester, when applied at maximum rates in spring and late summer, had a
moderate effect on Pacific silver fir.  Triclopyr ester had no effect
when applied in summer [10].

Pacific silver fir is damaged by mountain beaver, black bear, and
porcupine, which increases susceptibility to pathogens [56].  Wounds
result in wetwood, circular or radial shake, and frost cracks [3].

Pacific silver fir is among those species that are most seriously
affected by annosus root disease (Heterobasidion annosum).  The
incidence of fungal infestations is higher in stands 200 years or older
than in younger stands [14].  Often a rotation of 40 to 120 years and
minimization of wounding trees will reduce intermediate entry of the
pathogen [22].  Airborne infection of Pacific silver fir is high
year-round [14].  Annosus root disease infects trees when roots grow in
contact with infected fungus food base.  Other trees become infected
through root contacts.  Air-borne spores colonize wounds up to 1 month
old [62].  Trees with this fungus show butt rot, retarded leader growth,
sparse and chloritic foliage, and distress cone crops; mortality may
occur [22,55].  Young stands can have high infection levels with low
severity damage [70].  The fungus and tree can "wall off" each other,
but once the tree becomes weakened, the fungus will invade [22].

After being weakened by annosus root disease, infestation by
fir-engraver beetle (Scolylus ventralis), silver fir beetle
(Pseudohylesinus sericeus), or fir root bark beetle (Pseudohylesinus
granulalus) is frequent [14,22,55].  When beetle populations are high,
Pacific silver fir may be attacked and killed before symptoms of
infection are found.  These effects are enhanced during a drought [55].
Annosus root disease also causes stem decay [22].

The most reliable way to diagnose Annosus root disease is by the
presence of conks, or fruiting bodies, found in the duff layer at the
root collar on the outer bark.  Ectotrophic mycelium on the roots cannot
be used in diagnosing annosus root disease [55].

To prevent damage to trees during logging, options include using
rubber-tired skidders, working with a proven crew, and afterwards,
treating remaining stumps with a registered pesticide to prevent its use
as a food source [62].  At the time of logging, stump removal to reduce
innoculum in the soil is useful in preventing further contamination
[62].  Borax application can be part of timber sales contracts when this
treatment is considered appropriate [70].  Saplings and pole-sized trees
are too small to be effective innoculum sources.  Management should
involve reducing mortality, thinning fir trees at least 25 feet (7.5 m)
from dead trees, and minimizing wounding during salvage logging [22].

Armillaria (Armillaria ostoyae) is often a secondary pathogen of trees
infected with annosus root disease [55].  Pacific silver fir is
moderately susceptible to Armillaria.  In stands with smaller trees,
thinning those within 25 feet (7.5 m) of dead trees, reducing mortality,
and minimizing wounding is helpful.  Prescribed burning may slow
Armillaria growth [22].  Shoestring rot (Armillaria mellea) is also
detrimental to Pacific silver fir [14].

Fungi found in advance regeneration of Pacific silver fir are Indian
paint fungus (Echinodontium tinctorium) and Stereum sanguinolentum [20].
Indian paint fungus has been located on healthy stems and encased branch
piths of suppressed Pacific silver fir.  Decay is commonly found near
wounds [4].  Infection sites include small diameter branch stubs between
50 and 60 years of age [4].  Indian paint fungus has a dormant phase,
which occurs when wounded tissues heal [4].  When trees receive a new
injury, the fungus resumes growth [3].  Indian paint fungus is most
easily recognized by the presence of conks or slow decay in old large
wounds [22].  Stand rotation should be 150 years or less and wound
reduction activities should be practiced [22].  Filip and Schmitt [2]
discuss color recognition of Indian paint fungus and planning and
operational activities.

Pacific silver fir is moderately susceptible to laminated root rot
(Phellinus weirii), which creates forest patches of damaged or dead
trees when abundant [15].  Infected trees in sawtimber-sized stands
should be removed, followed with stump removal or replacement with
disease-tolerant species.  Air-drying the stumps kills the fungi.  Fire
is ineffective against annosus root disease, Armillaria, and laminated
root rot [56].

Potebniamyces dieback (Phacidium balsamicola) causes small branch
dieback and swelling at the girdling point but does not cause
significant losses.  Treatment involves spacing severely infected trees
at precommercial thinning levels.  For white-spored rusts (Uredinopsis
spp.), site preparation procedures should avoid encouraging the growth
of alternate hosts.  In severe cases, it may be necessary to apply
herbicide to alternate hosts.  There is no management practice known for
Virgilla robusta and Abies rust (Pucciniatrum spp.), except to minimize
the number of alternate hosts of Abies rust during site preparation.
Other fungi prevalent in fir stands include Caloscypha fulgens,
Sirococcus blight, and Sirococcus strobilinus [62].

Pacific silver fir is also susceptible to western spruce budworm
(Choristeneura occidentalis), Douglas-fir tussock moth (Orygia
pseudotsugata), and fir-engraver beetle [22,35].  The effects of these
pests can be alleviated by the application of fertilizer, and minimized
by variation of stand structure and by planting pest-tolerant species
[22].  At sites of western spruce budworm infestation, treatment should
decrease the number of vulnerable trees and should increase the number
of young trees by lowering maximum tree sizes.  Ambrosia beetles
(Trypodendron lineatum and Gnathotrichus sulcatus) can be captured with
pheromone, multifunnel traps in late June when the beetles are flying.
Harvesting should be planned so that logs are not left on the ground to
be attacked by ambrosia beetles [45].  One of the most devastating pests
to Pacific silver fir is balsam woolly aphid (Adelges piceae) [14,57].
Infested trees appear swollen, with gouty twigs, poor crowns, and little
growth; death occurs within 2 to 3 years [22].  Infested trees have
mottled-red foliage, distinct "crown lean", and appear to die from the
top down.  Trees greater than 28 inches (71 cm) in d.b.h. sustain the
most damage among the dominant crown classes [29].  In order to protect
nearby stands, the advance regeneration must be destroyed and the site
should be returned to a seral habitat, such as western hemlock [56].

Pacific silver fir is a secondary host for dwarf mistletoe (Arceuthobium
tsugense and Arceuthobium abietinum) [14].  Dwarf mistletoes cause
growth loss and tree mortality when in association with canker fungi
(Cytospora abietis).  The key management practices should be detection,
evaluation, prevention, and suppression.  Living infected residues
should be killed before susceptible regeneration reaches 3 feet (0.9 m)
or 10 years of age [22].  Ruth [57] suggests removing the overstory and
burning seedlings and other residue material in seedling infected
stands.  Slash burning may be one of the most effective tools to
eliminate dwarf mistletoe.  Special site preparation and herbicides may
also be useful tools for treatment [56].

Related categories for Species: Abies amabilis | Pacific Silver Fir