BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Abies fraseri | Fraser Fir 



GENERAL BOTANICAL CHARACTERISTICS : 
Fraser fir is a native, evergreen coniferous tree.  It is small to
medium sized; the largest on record is 87 feet (26.5 m) tall and 34
inches (86 cm) d.b.h.  The usual range is from 50 to 60 feet (15-18 m)
tall and less than 12 inches (30 cm) d.b.h.  Average age at death is 150
years [2].

Fraser fir is very shallow rooted [2].  The bark is nearly smooth, with
blisters containing an oleoresin; the bark becomes more scaly on older
trunks.  Pollen cones are usually less than 0.4 inch (1 cm) in length,
ovulate cones are 1.6 to 2.2 inches (4-5.5 cm) long [23].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Sexual reproduction:  Seed production in Fraser fir begins at about 15
years of age.  Good seed crops are produced every other year, with light
crops in intervening years.  Seeds are wind dispersed, with 50 percent
falling at least 900 feet (274 m) from the source; seeds can be carried
up to 1 mile (1.6 km) from the source [2].

Seed germination is good on mineral soil, moss, peat, and litter.
Decaying stumps and logs have higher than average rates of seedling
establishment and appear to be the best substrates for germination
[2,7,22].  Germination on surface litter usually results in seedling
mortality due to drought.  Stratification does not enhance germination
rates [2].  Seed longevity in the soil is unknown; viability may
decrease after only 1 year of artificial storage [22].  Natural
reforestation is limited where harvesting or fire has opened canopies
and increased the rate of desiccation of the moss and peat layer [2].

Asexual reproduction:  Fraser fir sometimes reproduces by layering when
lower branches come into contact with moist soil.  This is not an
important reproductive mechanism [2].


SITE CHARACTERISTICS : 
Fraser fir occurs in a cool-temperate, rain-forest climate with a
well-distributed mean annual precipitation ranging from 75 to 100 inches
(1,900-2,540 mm).  Fog is present for 65 percent or more of the growing
season, actual moisture levels are therefore higher than measured
precipitation indicates [2].

Fraser fir occurs on soils with a wide variation in color, depth, and
amount of organic matter; they are usually shallow and rocky, and
bedrock is within 20 to 32 inches of the mineral soil [2].  At upper
elevations where dense and stagnant stands have formed, soils are
usually podsolic and highly acidic.  In a spruce-fir forest at 6,500
feet (1,980 m) in elevation, soil pH was 3.6 at the surface and 3.8 6
inches (15 cm) below the surface [4].

Fraser fir generally occurs at elevations ranging from 5,500 feet (1,676
m) to 6,684 feet (2,037 m).  It may occur as low as 4,500 feet (1,372 m)
on north slopes and protected coves.  At lower elevations, Fraser fir is
a minor component in spruce-fir forests; it increases in frequency with
altitude [2,3,5].


SUCCESSIONAL STATUS : 
Obligate Climax Species

Once established, Fraser fir seedlings grow best in full light.  Fraser
fir is, however, very shade tolerant and can grow under dense canopies
in a suppressed state for many years.  Under these conditions, Fraser
fir may only be 2 to 3 feet (0.6-0.9 m) in height after 20 years of
growth.  In full sun, Fraser fir can be 8.2 feet (2.5 m) after 11 years.
When released after years of suppression, growth of Fraser fir can be
very rapid [2].  Fraser fir often forms dense, stagnant pole-sized
stands at higher elevations [4].

In the red spruce-Fraser fir forests of the southern Appalachians,
windfalls that create small gaps (less than [200 sq m]) are the most
important and widely distributed disturbance, with a return interval of
111 to 178 years [7,29].  Gap capture is largely dependent on advance
reproduction; Fraser fir seedling and sapling densities are higher in
gaps than in the understory.  There is a probable reciprocal replacement
between red spruce and Fraser fir [29].  Similarly, in a study of the
dynamics of tree replacement in red spruce-Fraser fir forests, saplings
of Fraser fir were more numerous than those of red spruce, and were
found in higher densities under red spruce trees [13].  Both species
require multiple release events in order to reach the canopy [29].

Fraser fir was found in late seral to climax communities developed
during primary succession on rocky slopes [7].


SEASONAL DEVELOPMENT : 
Fraser fir cones open in mid-May to early June.  Cones ripen from
September to mid-October, and seed dispersal follows maturation [2].
Reproductive bud differentiation coincides with rapid vegetative growth
and cone development [1].

Related categories for Species: Abies fraseri | Fraser Fir