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Douglas
Fir
Common
Name(s):
Douglas Fir
Scientific
Name:
Pseudotsuga
menziesii Franco
Scientific
Name Synonyms:
None known
Symbol:
PSME
Description:
Life Span: Perennial
Origin:
Native
Season: Evergreen
Growth Characteristics:
Douglas
fir is a medium-sized evergreen tree with a short pyramidal symmetrical
crown at the top of a clear straight trunk. The average size of
this tree in Utah is 130 feet tall, and 36 inches in diameter.
Flowers/Inflorescence:
The
male and female cones are separate, often found on the same twig.
Male cones are numerous, very small, and orange-red in color. Female
cones, which mature in one growing season, appear at first as purplish
or red-green clusters of three-pronged leafy bracts. When mature,
the cones are 2 - 4 inches long and brown in color. Woody cone scales
are stiff with protruding three-pronged leaf-like bracts that wrap
back over the next lower cone scale, these have the appearance of
the back legs and tail of a mouse.
Fruits/Seeds:
Seeds are small, thin-shelled nuts, about ¼ inch long with
terminal wings that averages ¾ inch in length.
Leaves: Needle-like,
but flat, flexible, and without sharp tips. They are about 1 inch
in length, attached to the twig by short, twisted petioles. The
leaves are commonly bluish-green in color. Buds are slender, about
¼ inch long, non-resinous, sharp pointed, and reddish-brown.
Stems: Twigs
are slender, orange-brown, and covered with short silky hairs. Bark
is variable, being very thin on young trunks to as much as 6 inches
thick on old mature trunks. Resin blisters are common on young poles
and saplings. The bark surface is smooth on young stems and deeply
furrowed between rough gray-brown ridges when mature. The wood is
light tan to reddish in color, soft, and fine-grained. It is excellent
quality for lumber.
Ecological
Adaptations:
Douglas
fir is most commonly found on cool, moist, north facing slopes or
canyon walls. It is most abundant in nearly pure stands at elevations
between 5,000 and 8,000 feet, generally in a belt above ponderosa
pine and below Englemann spruce and subalpine fir. It is shade tolerant
and often found replacing or "growing up through" aspen
stands.
Soils: Grows
on a wide variety of soils, but develops best on clay loams, silty
clay loams, and silty loams which are deep, moist, and well drained.
Associated Species:
Ponderosa
pine, lodgepole pine, limber
pine, Englemann spruce, Aspen,
and blue spruce.
Uses and
Management:
Douglas
fir is an important and valuable timber tree, accounting for nearly
¼ of the total lumber produced in North America. The wood
is used widely as dimensional lumber, timbers, and plywood. The
wood is also used for railroad ties, mine timbers, house logs, post
and poles, fencing, and firewood. It is used extensively for Christmas
trees.
Douglas fir provides cover and habitat for both wildlife and livestock.
The seeds are an important food source for birds and small mammals.
The needles (leaves) are eaten by blue grouse and spruce grouse.
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