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National Plant Data Center

PACIFIC SILVER FIR

Abies amabilis (Dougl. ex

Loud.) Dougl.

Plant Symbol = ABAM

Contributed by: Santa Barbara Botanic Garden and

USDA NRCS National Plant Data Center

Susan McDougal, The Flora of Mt. Adams

Uses

Pacific silver fir is used in urban landscaping and

grown commercially for Christmas trees. When used

for landscaping, sufficient space should be allocated

for the relatively large size of mature trees. The soft,

light-weight wood is weak and has low durability. It

has been used for light construction frames,

construction plywood, container veneer, and

pulpwood.

The dense growth of Pacific silver fir provides cover

and protection during the winter for wildlife. Old-

growth stands provide habitat for mountain goat,

northern spotted owl, Vaux’s swift, western red-

backed vole, and the Olympic salamander. Seeds

provide food for birds, rodents, and squirrels, while

the leaves of growing shoots are browsed by elk.

Status

Please consult the PLANTS Web site and your State

Department of Natural Resources for this plant’s

current status (e.g. threatened or endangered species,

state noxious status, and wetland indicator values).

Description

General: Pine Family (Pinaceae). Pacific silver fir is

a U.S. native conifer that ranges from 100 to 230 feet

tall and up to 45 inches in diameter at the base. Like

all true firs, it has erect, cylindrical cones that are

borne near the tips of the uppermost branches.

Secondary branches and twigs are typically in pairs,

with leaves twisted or curved so that they tend to lie

in one plane. Mature cones are 3.5 to 6 inches long

and purple. Mature trees are erect, conical in outline,

with spreading, spray-like branches and a scaly, gray

to whitish bark. Young shoots have a dense, short,

pinkish brown pubescence. Most of the needle-like

leaves range from 0.5 to 1.3 inches long, are bright

green, somewhat flattened, and have notched tips.

Distribution: For current distribution, please consult

the Plant Profile page for this species on the

PLANTS Web site.

Adaptation

Native to the Pacific Northwest, Pacific silver fir

ranges from southern Alaska to northern California.

Well developed stands are primarily found at

elevations from 1,000 to 7,000 feet on the coastal

slopes of the Cascades. However, in the northern

part of its range, stands occur well below 1,000 feet.

Pacific silver fir usually occurs in uniform stands or

associated with western hemlock (Tsuga

heterophylla). The geographic range is characterized

by a maritime to submaritime climate, with an annual

precipitation between 40 to 260 inches per year, and

average summer temperatures between 57 to 59

degrees F. Plants have a mild frost tolerance and a

low tolerance for frozen soil conditions. Soils are

usually very moist, somewhat acidic (pH 5), and rich

in magnesium and calcium. A thin bark and highly

flammable foliage contribute to low levels of

resistance to fire.

Establishment

Pacific silver firs reproduce only from seed. Both

pollination and seed dispersal are effected by wind.

Plants are capable of self-fertilization and produce

mature cones and seeds two years after pollination.

Cones disintegrate while on the tree and seeds are
http://plants.usda.gov/java/largeImage?imageID=abam_008_avp.tif

either dispersed by wind or small mammals. Cool

moist sites are optimal for germination, but full

sunlight produces maximum growth. Germination

can occur on a variety of substrates, including litter,

rotten wood, moss, and organic and mineral soils.

Management

Management for most fungal diseases involves

thinning at least 25 feet from dead trees and

minimizing wounding during logging or trimming.

Treating remaining stumps with fungicide or stump

removal after logging is useful in preventing further

contamination. In some cases, removal of infected

trees and trunks should be practiced as soon as

disease is diagnosed. Air drying large stumps often

reduces chances of further infection.

Pests and Potential Problems

Pacific silver firs are susceptible to several fungal

diseased, including Annosus root disease

(Heterobasidion annosum). Infected trees may show

retarded leader growth, sparse and chlorotic foliage,

stem decay, and abortive cones. The most reliable

way to detect this disease is by the presence of

fruiting bodies in the duff layer at the root collar on

the outer bark. Trees become infected by rood

contact or by airborne spores falling onto woonds.

Other fungal diseases include Indian paint fungus

(Echinodontium tinctorium) and laminated root rot

(Phellinus weirii). Both can infect stands of trees and

result in patches of damaged or dead trees.

Trees weakened by disease or poor growing

conditions may become infested with fir-engraver

beetle (Scolylus ventralis), silver fir beetle

(Pseudohylesinus sericeus), or fir root bark beetle

(Pseudohylesinus granulatus). In large numbers,

these beetles may kill entire trees before any

symptoms are observed. Pacific silver firs are also

susceptible to Western spruce budworm

(Choristeneura occidentalis), Douglas fir tussock

moth (Orygia pseudotsugata) infestation. Applying

fertilized and varying the age and density of stands

reduces the infestation. Balsam wooly aphids

(Adelges piceae) are an extremely devastating pest to

this species. Infected trees appear swollen with little

growth and usually die from the top down within 2 to

3 years. To prevent further infestation, most trees

need to be removed and the site rplanted with such

species as western hemlock.

Seeds and Plant Production

Cone production may begin at an age of 20 to 30

years. Each cone can produce up to 400 seeds, but

the percentage of viable seed ranges from 6.3 to 35

percent. Preferred methods of cone collecting

include extension poles with appropriate pruners.

Cones should be collected between mid and late

August or just prior to disintegration. They should be

stored in well-ventilated bags or sacks at

temperatures between 70 and 80 degrees until the

cones have disintegrated. Seeds can be extracted

mechanically by using screens and then cold-

stratified under dry conditions at temperatures

between 10 and 30 degrees F for 4 to 6 months.

Germination is best accomplished by placing them in

a moist, well-aerated soil mix at temperatures

between 35 and 40 degrees F. Light enhances

germination and development of seedlings. Plant

can be grown either individually in containers or in

flats prior to transplantation. Under field conditions,

seed should be sown in the spring at a density of 62.5

to 125 per acre and approximately 0.25 inches deep.

During the first few years, growth ranges from 4 to

16 inches annually. Fertilizer combined with

thinning enhances growth.

Cultivars, Improved, and Selected Materials (and

area of origin)

Contact your local Natural Resources Conservation

Service (formerly Soil Conservation Service) office

for more information. Look in the phone book under

”United States Government.” The Natural Resources

Conservation Service will be listed under the

subheading “Department of Agriculture.”

Cultivars include a slow-growing, broadly ovoid

form, ‘Compacta’ and a low-growing, spreading form

with horizontal branches, ‘Spreading Star.’ Retail

nurseries in the Pacific Northwest that stock native

shrubs and trees may carry the cultivars.

References

Arno, S. & R. Hammerly. 1977. Northwest trees. The

Mountaineers, Seattle, Washington. 222 p.

Dickman, A. & S. Cook. 1989. Fire and fungus in a

mountain hemlock forest. Canadian Journal of Botany

67:2005-2016.

Filip, G. & C. Schmitt. 1990. Rx for Abies:

Silvicultural options for diseased firs in Oregon and

Washington. USDA Forest Service, Pacific

Northwest Research Station, Gen. Tech. Report 252.

34 p.

Klinka, K., V. Krajina, A. Ceska, & A. Scagel. 1989.

Indicator plants of coastal British Columbia.

University of British Columbia Press, Vancouver.

288 p.

Krajina, V., K. Klinka, & J. Worrall. 1982.

Distribution and ecological characteristis of trees and

shrubs of British Columbia. University of British

Columbia, Vancouver. 131 p.

Oliver, C. & R. Kenady (eds.). 1982. Proceedings of

the biology and management of true fir in the Pacific

Northwest. University of Washington, College of

Forest Resources, Contribution No. 45, Seattle.

USDA NRCS. 2007. The PLANTS website.http://plants.usda.gov. Accessed 070117. National

Plant Data Center, Baton Rouge, Louisiana.

Prepared By

Dieter Wilken, Santa Barbara Botanic Garden, Santa

Barbara, California

Species Coordinator

Dieter Wilken, Santa Barbara Botanic Garden, Santa

Barbara, California

Edited: 070117 jsp

For more information about this and other plants, please contact

your local NRCS field office or Conservation District, and visit the

PLANTS Web site or the Plant Materials

Program Web site

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of Civil Rights, Room 326-W, Whitten Building, 14th and

Independence Avenue, SW, Washington, DC 20250-9410 or call

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