Associated Forest Cover
provided by Silvics of North America
Tree species associated with balsam fir in the boreal region of Canada
are black spruce (Picea mariana), white spruce (Picea glauca),
paper birch (Betula papyrifera), and quaking aspen (Populus
tremuloides). In the more southerly northern forest region, additional
associates include bigtooth aspen (Populus grandidentata), yellow
birch (Betula alleghaniensis), American beech (Fagus
grandifolia), red maple (Acer rubrum), sugar maple (Acer
saccharum), eastern hemlock (Tsuga canadensis), eastern white
pine (Pinus strobus), tamarack (Larix laricina), black ash
(Fraxinus nigra), and northern white-cedar (Thuja
occidentalis). Red spruce (Picea rubens) is an important
associate in New Brunswick and Maine. Occasional associates are balsam
poplar (Populus balsamifera), gray birch (Betula populifolia),
red pine (Pinus resinosa), jack pine (Pinus banksiana),
and American elm (Ulmus americana) (10).
Pure stands of balsam fir or stands in which balsam fir is the major
component of growing stock make up the forest cover type Balsam Fir
(Society of American Foresters Type 5) (10). Balsam fir is also a major
component in two other eastern forest cover types: Red Spruce-Balsam Fir
(Type 33) and Paper Birch-Red Spruce-Balsam Fir (Type 35). It is an
associated species in 22 eastern forest cover types and in 4 western
forest cover types.
Common shrubs associated with balsam fir include beaked hazel (Corylus
cornuta), mountain maple (Acer spicatum), Labrador-tea
(Ledum groenlandicum), Canada yew (Taxus canadensis), red
raspberry (Rubus idaeus var. strigosus), sheep-laurel (Kalmia
angustifolia), and hobblebush (Viburnum lantanoides) (10,41).
Among the herbaceous plants commonly found under balsam fir are
twinflower (Linnaea borealis), bunchberry (Cornus canadensis),
starflower (Trientalis borealis), creeping snowberry (Gaultheria
hispidula), sedges (Carex spp.), common woodsorrel
(Oxalis montana), bluebead lily or cornlily (Clintonia
borealis), painted trillium (Trillium undulatum), cinnamon
fern (Osmunda cinnamomea), sweetscented bedstraw (Galium
triflorum), Canada mayflower (Maianthemum canadense), and
spinulose woodfern (Dryopteris spinulosa).
Certain associations of shrubs, herbs, and mosses indicate forest site
quality (41). The four main indicator associations, designated as
Hylocomium/ Hypnum, Cornus/Maianthemum, Oxalis/Cornus, and Viburnum/Oxalis
indicate, in the order listed, increasing productivity of site and
increasing proportions of shrubs and hardwood trees in natural stands.
Only the Hylocomium/Hypnum sites are likely to be occupied by pure
balsam fir.
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Climate
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Balsam fir grows best in the eastern part of its range in southeastern
Canada and the Northeastern United States. This area is characterized by
cool temperatures and abundant moisture. Growth is optimum in areas with a
mean temperature of 2° to 4° C (35° to 40° F), a
January average ranging from -18° to -12° C (0° to 10°
F), a July mean temperature ranging from 16° to 18° C (60°
to 65° F), and mean annual precipitation ranging from 760 to 1100 mm
(30 to 43 in) (1).
The mean annual temperature within the range of balsam fir varies from
-4° to 7° C (25° to 45° F). Mean annual precipitation
records show as much as 1400 mm (55 in) to as little as 390 mm (15 in).
The amount of growing season precipitation is from 150 to 620 mm (6 to 25
in) (1). There are 80 to 180 frost-free days and about 110 days for
optimum growth (1).
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Damaging Agents
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Many agents act to hinder the growth of balsam
fir. Insects and diseases may be devastating. Flammable needles, often
close to the ground, shallow root systems, and thin resinous bark make
balsam fir susceptible to severe damage and mortality from fire.
Susceptibility to wind damage is especially high in old unmanaged stands
growing on wet shallow soils. Various species of mice, voles, and birds
consume balsam fir seed; birds and squirrels nip buds; and black bears
girdle mature trees.
Balsam fir has several insect enemies, the most important by far being
the spruce budworm. Despite its name, the spruce budworm prefers fir over
spruce; it is most likely to cause heavy damage and mortality in stands
that contain mature fir, or that have a dense stocking of fir or a high
proportion of fir in relation to other species. Vast budworm outbreaks in
eastern North America, perhaps as many as 11 since 1704, have killed tens
of millions of cubic meters (hundreds of millions of ft³) of balsam
fir (6). Defoliation causes extensive root mortality. Evidence of budworm
attack such as deformation, buried leaders, and decay can be seen 40 or
more years later (1). Detailed articles about this important insect pest,
with suggestions to alleviate damage, have been written (7,32) and a
comprehensive bibliography assembled (25).
A classification system for tree vigor and budworm resistance was
developed as a guide for selecting spruce and fir trees to remove or
retain so as to make spruce-fir stands less vulnerable to spruce budworm
attack. Silvicultural techniques designed to increase stand resistance to
budworm cannot achieve their aim in the short term; several stand entries
over the long term may be required, especially in stands dominated by
balsam fir regeneration (46).
The balsam woolly adelgid (Adelges piceae), an introduced
insect, is found in Southeastern Canada and in the Northeastern United
States. Unless checked by low winter temperatures, populations build up
and weaken or kill many trees. Severe stem attack can kill trees within 3
years. The insect also attacks twigs and buds, causing swellings and
resulting in loss of new buds, gradual death of twigs and tops, and severe
damage to regeneration. An abnormal growth of tracheids caused by insect
saliva results in dark, brittle "redwood" (41).
The red heart fungus (Haematostereum sanguinolentum), causes
much decay in living balsam fir. It enters almost entirely through
injuries to the trunk and living branches (18). Losses from red heart rot
are two or three times greater than those caused by butt rots (11,41). Six
root and butt rots in balsam fir are economically important. These include
the shoestring rot (Armillaria mellea), the two brown cubical rots
(Tyromyces balsameus and Coniophora puteana), and the
three white stringy rots (Poria subacida, Resinicium bicolor, and
Scytinostroma galactinium). Another root disease of importance is
Serpula himantioides. Phaeolus schweinitzii and Inonotus
tomentosus also cause a small percentage of the root and butt rot in
balsam fir (18). Mechanical or insect-caused wounds to the roots or basal
areas of trees provide entrances for these fungi (41). Although the root
and butt rots are not responsible for an excessive amount of cull in
standing trees, they do weaken trees and make them more susceptible to
wind damage, especially if trees are 20 cm (8 in) d.b.h. and larger. The
defect caused by these rots is severe enough to be the decisive factor in
setting the pathological rotation of fir at about 70 years (11,18,41).
Rot can begin in balsam fir as early as 40 years and increases as the
trees get older. More than half generally are infected by the time they
are 70 years old. No reliable external indicator of rot is known and even
fruiting bodies are rare on living trees. Site seems to have an effect on
the incidence and severity of rot; generally, the drier the site, the
greater the damage from rot (41).
Specific causes of seedling diseases in nurseries have not been
thoroughly reported. The foliage diseases of balsam fir are many but none
are economically important to wood production. The same can be said for
balsam fir's many stem or canker diseases (18).
The most conspicuous disease of balsam fir is witches' broom, caused by
the rust fungus Melampsorella caryophyllacearum. Broomed shoots
are upright and dwarfed and have yellow needles. Trunk and branch
swellings are produced in the shoots (18).
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Flowering and Fruiting
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Exposure to light influences flowering
in balsam fir. In New Brunswick, female strobili were observed on 83
percent of dominant, 59 percent of codominant, and 6 percent of
intermediate trees. None were found on suppressed trees (41).
Balsam fir is monoecious. In spring, 1 year before pollination, male
(staminate) and female (ovulate or pistillate) strobili differentiate from
flower buds. The strobili are microscopically recognizable at this time.
Male strobili usually are distinguishable before the female strobili
because they initially develop more rapidly. Flower buds usually open in
late May or early June before vegetative buds (41) but have been
reported as flowering as early as late April (42).
Male strobili, yellowish-red and tinged with purple, develop in the
axils of leaves along the undersides of the 1-year-old twigs, usually in
dense clusters. Their position in the crown is mostly within 5 m (15 ft)
of the top and is almost always below the female strobili. Female strobili
are purplish and are found singly or in small groups, confined to the top
1.5 m (5 ft) of the crown. They are located on the upper side of the twig
and, like the male strobili, develop on the previous year's twig. Flower
production is best on the outer end of branches (41,42). At
maturity, male flowers are about 3 mm (0.1 in) long; female flowers are
about 25 mm (1.0 in) long (1).
Pollen grains are yellow; when developed, their average diameter is 90 µ
(0.00354 in). In one series of observations in Ontario, fertilization
occurred on June 25 (1). The mature fruit is an erect cone 5 to 10 cm (2
to 4 in) long with short, round, irregularly notched scales and pointed
tips. There are thin, closely overlapping fan-shaped scales near the
center of the cone. The cone matures and ripens during the first fall in
late August and early September. The scales and shorter bracts drop away
with the seeds, leaving the central axis, which can persist for many
years.
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Genetics
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Population Differences
Variation in balsam fir appears to be clinal and continuous and related
to altitudinal gradient and to both east-west and north-south geographic
gradients. Variation has been explored in a number of studies.
Balsam fir seedlings grown from seed collected along an elevational
gradient in New Hampshire showed a clinal pattern of carbon dioxide uptake
with respect to the elevational gradient. This suggests an adaption to
temperature through natural selection (14). Another study failed to show
that geographical variation in food quality of balsam fir needles is
important to the spruce budworm diet but did suggest variation in food
quality between locations (33).
In the southern Appalachians the monoterpenes- alpha-pinene and
beta-phellandrene- appear to be the best taxonomic characteristics for
separating balsam fir from Fraser fir, with alpha-terpene increasing
southward and beta-terpene increasing northward. Because no regional
variation pattern was evident for wood specific gravity or tracheid
length, it has been suggested that only one species of balsam fir with
three varieties be recognized in the Eastern United States: Abies
balsamea var. balsamea, Abies balsamea var. phanerolepis,
and Abies balsamea var. fraseri (29,39).
Balsam fir provenances from eastern portions of the range exhibited more
vigor than those from western portions (24). This trait continued
through 11 (22) and 13 years of total tree age (9). Southern
sources tended to flush later, indicating selection for minimizing damage
from the balsam gall midge (Dasineura balsamicola) and for
resistance to late spring frost.
Specific gravity and tracheid length generally vary along an east-west
gradient, with eastern sources of lower specific gravity and longer
tracheids (9). Generally, trees from slow-growing sources have
higher specific gravities and shorter tracheids than trees from
fast-growing sources.
Races and Hybrids
No distinct races of balsam fir have been identified. Botanical
varieties of balsam fir have been described, Abies balsamea var.
phanerolepis being most important. This variety, the bracted
balsam fir, is distinguished by its cone scales, which are shorter than
the bracts. The variety phanerolepis is found infrequently from
Labrador and Newfoundland to Maine and Ontario, and in the high mountains
of New Hampshire, Vermont, and New York. It is found locally in northern
Virginia and West Virginia (21,41,42), and commonly in several
locations in Nova Scotia.
Until the late 1930's, natural or artificial hybrids of balsam fir had
not been reported in North America. There were earlier reports, however,
of hybrids between balsam fir and Siberian fir (Abies sibirica) in
Europe (1).
Balsam fir is closely related to Fraser fir (A. fraseri). A
taxon of doubtful status, A. intermedia, representing a possible
cross between the two species, has been reported. This cross has also been
reported as A. balsamea var. phanerolepis (1). Subalpine
fir (A. lasiocarpa) also may hybridize with balsam fir where they
adjoin in Alberta (42). Workers in Canada apparently have been
successful in some instances in hybridizing balsam fir with several
species of Abies, among them European silver fir (A. alba),
alpine fir, and Fraser fir (1). Similar attempts in the United States
have been only partially successful.
European horticulturists have propagated many forms of balsam fir for
ornamental purposes. Plant form, needle color, and branch length and angle
are characteristics usually manipulated. Nineteen such cultivars have been
listed (1).
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Growth and Yield
provided by Silvics of North America
Balsam fir at maturity is small to medium
size, depending on location and growing conditions. In general, heights
range from 12 to 18 m (40 to 60 ft); diameters range from 30 to 46 cm. (12
to 18 in) at breast height (41). Where growth is optimum, as in the Green
River watershed in New Brunswick, some trees can reach 27 m (90 ft) in
height and 75 cm. (30 in) in d.b.h. The reported record d.b.h. for balsam
fir is 86 cm (34 in). Maximum age is about 200 years (1). How large or how
fast balsam fir grows, or how much a stand of balsam fir will yield is
related to site factors such as biotic, climatic, and soil conditions, and
to age. The condition of the tree or stand and the composition and
structure of the stand also influence growth.
Diameter growth was related to vigor and crown length-to-height ratio in
a study in Maine. Balsam fir with high vigor and a ratio of at least 0.7-
the proportion of live-crown length to total tree height averaged 6.1 cm
(2.4 in) of growth in d.b.h. in 10 years. Less vigorous trees with smaller
crown-length ratios ranged downward to an average of 1.0 cm (0.4 in) of
growth in 10 years. Vigorous trees with room to grow attain a d.b.h. of at
least 25 cm (10 in) in about 50 years (41). In uneven-aged stands of
several density classes in Maine, balsam fir grew faster in diameter than
spruce and hemlock (35).
Data obtained from stem analysis of balsam fir growing on sites of
varying quality in northern Maine has shown height growth curves to be
polymorphic (fig. 1). Height growth varies with site quality. From these
curves the average site index of a stand can be estimated (16).
Monomorphic or harmonized site index curves for balsam fir are also
available (17).
Figure 1-Polymorphic site index curves (base age 50 years
at breast height) for balsam fir in northern Maine, as derived
from stem data (16).
Balsam fir is a strong contender for space in stands in which it grows.
A 20-year record of stands containing balsam fir in the Penobscot
Experimental Forest in Maine showed that the periodic annual volume
ingrowth of the species, as a proportion of total volume ingrowth, greatly
exceeded its representation in the original stands (12). Because of its
many natural enemies, however, volume mortality of balsam fir also greatly
exceeds its original representation in these stands.
Balsam fir accounted for 35 percent of the average annual net growth in
predominantly softwood stands and 32 percent in mixed stands that were
extensively managed. These stands were growing at annual rates of 3.5 m³/ha
(49.3 ft³/acre) and 2.9 m³/ha (41.1 ft³/acre), respectively
(31).
Yields in total cubic-foot volume, including stump and top, of all trees
larger than 1.5 cm (0.6 in), in d.b.h. are given in table 1. These yields
are based on sample plots in even-aged spruce-fir stands, mostly on old
fields. They tend to exaggerate the yields that might be expected from the
irregular stands that develop after harvesting (41).
Table 1- Total tree volume (exclusive of roots) of
balsam fir greater than 1.5 cm (0.6 in) in d.b.h. by age and site index
(41).
Site index¹
12.2 m
or 40 ft
15.2 m
or 50 ft
18.3 m
or 60 ft
21.3 m
or 70 ft
Age
yr
m³/ha
20
6
8
9
12
30
50
67
85
102
40
136
182
229
276
50
204
274
344
414
60
245
329
413
497
70
267
360
452
543
80
286
384
481
579
90
300
403
506
609
yr
ft³/acre
20
80
110
135
165
30
720
960
1,210
1,455
40
1,940
2,600
3,270
3,940
50
2,190
3,920
4,920
5,910
60
3,500
4,700
5,900
7,100
70
3,820
5,140
6,450
7,760
80
4,080
5,480
6,870
8,270
90
4,290
5,760
7,230
8,700
¹Base age 50 years when age is measured at
d.b.h.- total tree age is estimated to be 65 years at that time.
Simulating the management and growth of forest stands containing balsam
fir is possible because of advances in computer technology. A matrix
model, FIBER (36), has been developed for stands in the Northeast.
Even-aged and multi-aged stands, containing balsam fir, spruce, northern
hardwoods, and other associated species, can be programmed to simulate a
range of silvicultural treatments.
In a ranking with both hardwoods and softwoods from around the world,
balsam fir is highest with a total above-ground ovendry biomass at age 50
of 184 t/ha (82 tons/acre). Annual increment or annual net primary
production averages 10.3 t/ha (4.6 tons/acre) (20). In New Brunswick (3),
dry-matter production of balsam fir in pure stands increased dramatically
with increases in stand densities of from 1,730 stems per hectare
(700/acre) to 12,350/ha (5,000/acre). At an average age from release of 43
years, total above-ground biomass was 96 t/ha (43 tons/acre) for the least
dense stand and 143 t/ha (64 tons/acre) for the most dense stand.
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Reaction to Competition
provided by Silvics of North America
Balsam fir has a strong ability to
become established and grow under the shade of larger trees (7,11). It is
classified as very tolerant. Because relative tolerance of species may
vary with soil fertility, climate, and age, balsam fir is rated as both
more and less shade tolerant than red spruce, and more tolerant than
either black or white spruce (41). Intraspecific competition is evident in
many sapling and small pole-size stands of pure balsam fir. As these
stands mature, dominance usually is expressed. Competition is severe in
dense fir thickets, however, and growth rates of individual trees suffer
greatly. Other major competition is from the shade-tolerant hardwoods.
In New England, balsam fir is considered a subclimax type, except that
it may be a climax species in the zone below timberline. It tends to
become climax in Quebec and in the Lake States (41).
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Rooting Habit
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Balsam fir root systems are mostly confined to
the duff layer and to the upper few centimeters of mineral soil (11).
Windfall potential is high. Damage from wind is especially likely when the
shallow root systems are loosened by heavy rainfall and gusty winds and
where timber removals from stands not previously thinned have been poorly
conducted. These usually older, dense stands are susceptible probably
because root development has been poor.
Root penetration on deep or shallow soils extends to 60 to 75 cm (24 to
30 in) and has been reported to a depth of 137 cm (54 in) in sandy soils
in northern Ontario. Lateral roots of balsam fir are usually strongly
developed and extend horizontally in all directions to 1.5 m (5 ft) or
more (1).
Root breakage and other root damage caused by swaying trees may not be
as severe as is commonly thought. Most investigators agree, however, that
some root breakage probably occurs because of frostheaving and swaying.
During epidemics of spruce budworm (Choristoneura fumiferana), rootlet
mortality can reach 75 percent after 3 consecutive years of defoliation
(1).
Balsam fir root grafts are probably common and have been reported
frequently. Abrasion of the bark of roots of swaying trees on lowland
soils and interroot compatibility and growth pressure on upland soils
apparently account for the majority of root grafts. Infection may spread
through grafted roots to damage other balsam fir trees (1).
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Seed Production and Dissemination
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Regular seed production
probably begins after 20 to 30 years. Cone development has been reported
for trees 15 years of age and younger and only 2 m (6.6 ft) tall. Good
seed crops occur at intervals of 2 to 4 years, with some seed production
usually occurring during intervening years (1). On the average, 35 L
(bushel) containing 1,000 to 2,000 cones weighs approximately 16 kg (35
lb) and yields 1000 to 1200 g (35 to 42 oz) of cleaned seeds. The number
of cleaned seeds per kilogram (2.2 lb) ranges from 66,000 to 208,000 and
averages 131,000. These are about 134 seeds per cone (42). The seed yield
of balsam fir ranged from 5.6 to 20.2 kg/ha (5 to 18 lb/acre) during
several good seed years in Ontario (1). Over a 37-year period, annual seed
production in this area averaged 1,950 seeds per square meter (181/ft²)
(15).
The period of balsam fir seedfall is long and dissemination distances
vary. Seedfall begins late in August, peaks in September and October, and
continues into November. Some seeds fall throughout the winter and into
early spring. Most of the seeds are spread by wind-some to great distances
over frozen snow-and some are spread by rodents. Although seeds may
disseminate from 100 m (330 ft) to more than 160 m (525 ft), effective
distances are 25 m to 60 m (80 to 200 ft) (1,11,28). Many seeds falling
with the cone scales land close to the base of the tree.
Balsam fir seeds have dormant embryos and should be stratified in moist
sand at about 50 C (410 F) for at least 30 days before planting.
Germination is epigeal (42).
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Seedling Development
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Within the range of suitable temperatures,
moisture is more important than light for germination. In fact, light
intensities of only 10 percent of full sunlight result in successful
germination (1). The low capacity of planted balsam fir seeds to germinate
may be attributed in part to seed injury during the cleaning process. The
age of the tree may also contribute to the viability of seeds.
A study in Michigan (41) showed that germination was highest for a
41-year-old tree (68 percent), varied for trees 30 years old (8 to 57
percent), and was lowest for trees 155 years old (10 percent). Testing of
32 commercial seed lots showed average germination of about 26 percent
with a range of 4 to 62 percent (42). Once the seed reaches the ground,
its viability diminishes quickly and is gone within 1 year (13). It has
been suggested, however, that in cold swamps viability of some seeds is
retained for 2 to 3 years (1).
Most germination occurs from late May to early July. Survival the first
winter is questionable if germination occurs after mid-July (1). If enough
moisture is available, almost any seedbed type is satisfactory, but
mineral soil-neither too sandy nor too heavy-with some shade is best.
Litter and humus are poor seedbeds, especially if moisture is inadequate
or -light is excessive. Competition, often severe, makes heavy sod the
poorest seedbed (11).
A thick layer of duff exceeding about 8 cm (3 in) is less favorable for
balsam fir but even worse for the slower growing associated spruces.
Balsam fir seedlings may have a heavy central root, much like a taproot,
that extends to the bottom of the humus layer and then splits into several
laterals. In general, balsam fir roots grow more rapidly and penetrate
deeper than red spruce roots. Where seasonal root elongation of young
balsam fir growing in humus averaged 10.6 cm (4.2 in), red spruce was 7.6
cm (3.0 in), and white spruce 9.0 cm (3.5 in), or 39 percent and 18
percent less, respectively (1).
Because the surface of thick duff usually dries out, there may be some
delayed germination as late as August. Few seedlings become established,
however. The closer seeds lie to mineral soil, the greater the initial
establishment of seedlings.
Seedlings starting in the open may sustain heavy mortality when surface
temperatures exceed 46° to 54° C (115° to 130° F) or
when there is drought or frost heaving. Seedlings may also be smothered or
crushed by litter, ice, snow, and hardwood leaves. Losses after the first
year usually are minor. As seedlings develop, light at intensities of at
least 50 percent of full sunlight are necessary for optimum growth
(11,41). Damage caused by late spring frost to new foliage of young
seedlings is seldom severe.
Balsam fir seedlings about 15 cm (6 in) tall can be considered to be
established (11), especially if secondary branching has occurred. Early
growth is then determined largely by the amount and character of dominant
competition. Bracken, raspberry, and hardwood sprouts-especially the
maples-are the chief competitors on heavily cutover lands in the
Northeast. These species may increase dramatically when the original basal
area is reduced by 50 percent or more and may dominate the site for 10 to
25 years (2). Unless there has been some soil disturbance, there will be
little regeneration of balsam fir and spruce immediately following logging
(45). Both balsam fir and the spruces can survive many years of
suppression and still respond to release (11,41). The space required for
the continual development and establishment of new seedlings probably
exceeds that created by the removal of individual trees. To ensure
successful regeneration relatively small groups of trees should be removed
initially (12).
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Soils and Topography
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Balsam fir grows on a wide range of inorganic and organic soils
originating from glaciation and generally falling within the acid
Spodosol, Inceptisol, and Histosol soil orders. These are characterized by
a thick mor humus and a well-defined A2 horizon,
usually gray in appearance because of leaching, and commonly caused by
abundant rainfall, cool climate, and coniferous cover. Many of the glacial
till soils in New England are shallow and have a compact layer about 46 cm
(18 in) below the surface (11).
Soil moisture was the most important predictor of site index in a study
in Newfoundland. Soil nutrient status and topography, in that order, were
of lesser importance. Glacial tills, often shallow, cover much of the area
(27).
Balsam fir has been reported as growing on soils of a wide range of
acidity. In the northern Lake States it is most common on cool, wet-mesic
sites with pH values between 5.1 to 6.0 (19). Optimum growth occurs on
soils where the pH of the upper organic layers is between 6.5 and 7.0 (1).
On gravelly sands and in peat swamps, growth is comparatively slow (41).
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Special Uses
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The most important products made from balsam fir wood are pulpwood and
lumber (43). The wood of balsam fir, as well as that of other true firs,
is creamy white to pale brown. The sapwood has little odor or taste. Wood
structure in the true firs is so similar that identification of species is
impossible by examining only the wood (1,43).
Balsam fir is pulped by all of the pulping processes. Sulfate and
semichemical processes are used most extensively. A fiber length of 3 to 4
mm A 12 to 0.16 in) is good, as is fiber quality. Because balsam fir is
less dense than other major pulpwood species, its yield is lower (37).
The wood of balsam fir is light in weight, relatively soft, low in shock
resistance, and has good splitting resistance. Recent testing of several
mechanical properties of balsam fir and of red, white, and black spruce
indicates strength values for balsam fir generally exceeding those of
white spruce. In some tests, strength values were equivalent to or only
slightly below the values of red and black spruce (5,34). Nail-holding
capacity is low. Balsam fir is very low in resistance to decay (43). The
major use of balsam fir lumber is for light-frame construction. Minor uses
include paneling, crates, and other products not requiring high structural
strength.
Balsam fir provides food or cover for some animals and both food and
cover for others. Moose rely on balsam fir in winter when it is a major
source of food. The use of balsam fir by deer for cover and shelter is
well documented. During severe winter weather, especially in northern
areas of the white-tailed deer range, lowland balsam fir stands and
spruce-balsam fir swamps are used extensively as winter yarding areas. The
fact that these sites usually contain, at best, only small amounts of
preferred food suggests their attractiveness as shelter.
Other mammals use balsam fir to varying degrees. The snowshoe hare uses
it for cover, and there is some seed and phloem feeding by various species
of mice and voles. Red squirrels occasionally feed on balsam fir seed,
bark, and wood. They prefer flower buds to vegetative buds. There is some
use of wood by beaver for dam building, but little is used as food. Black
bear strip bark and lick the exposed surfaces between bark and wood (1).
Balsam fir provides a minor part of the diet for both the spruce grouse
and the ruffed grouse. Buds, tips, and needles are consumed, and more
feeding occurs in winter than in summer. Thickets of balsam fir provide
shelter for both birds (1). The response of bird populations to several
forestry practices in stands containing balsam fir has been recorded
(8,40). Species composition, the vertical and horizontal structure of the
stand, and the extent of spruce budworm infestation influence the
composition and density of bird populations.
Balsam fir is not widely planted as an ornamental nor does it offer much
potential in areas other than northern New England, Canada, and perhaps
the Lake States. Plantings as screens or as windbreaks are successful only
when the moisture requirement of the species is met (1). On certain lands
and especially on public lands, the unique presence of spruce-fir stands
suggests management for esthetic values. In the southern Appalachian
mountains, coniferous forests containing balsam fir are managed for
watershed protection (44).
Oleoresin, a substance confined to the bark blisters of balsam fir, is
used as a medium for mounting microscopic specimens and as a cement for
various parts of optical systems. It is also used in the manufacture of
medicinal compounds and spirit varnishes (4).
Balsam fir wood is not prized for fuelwood, but industries that use
balsam fir for pulp and lumber products are using increasingly larger
quantities of wood waste for the production of energy. The heating value
of ovendry fir bark is 21 166 600 joules/kg (9,100 Btu/lb) (26).
The fir tree has been a favorite Christmas tree for more than 400 years.
It remains among the top three species. In 1980, balsam fir ranked second
behind Scotch pine (Pinus sylvestris), commanding 13.9
percent of the market (38). Sheared plantation-grown trees are usually
preferred over wildings by retailers and consumers. Wreath-making is
another holiday business that rivals that of Christmas tree sales in some
areas. Prolonged needle retention after harvest, color, and pleasant
fragrance are characteristics of balsam fir that make it attractive for
these uses. Fragrance alone accounts for use of the needles as stuffing
for souvenir pillows commonly sold in New England gift shops.
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Vegetative Reproduction
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Layering is not an important means of
regeneration except for prostrate balsam fir growing in the more northern
and mountainous locations such as Isle Royale in Lake Superior, and the
White Mountains of New Hampshire. Layering also occurs in open swamps and
deep mossy areas and under white pine and jack pine overstories. Trees of
any age apparently may layer. Second generations, vegetatively produced,
develop when connecting tissues decay and separate (1).
Balsam fir apparently grafts easily (41). In a study in New York,
greenhouse grafts were 85 percent successful and field grafts were 80
percent successful. One attempt to air-layer balsam fir was unsuccessful
(1). Balsam fir Christmas trees are stump cultured from lateral branches
or adventitious shoots.
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Distribution
provided by Silvics of North America
In Canada, balsam fir extends from Newfoundland and Labrador west
through the more northerly portions of Quebec and Ontario, in scattered
stands through north-central Manitoba and Saskatchewan to the Peace River
Valley in northwestern Alberta, then south for approximately 640 km (400
mi) to central Alberta, and east and south to southern Manitoba.
In the United States, the range of balsam fir extends from extreme
northern Minnesota west of Lake-of-the-Woods southeast to Iowa; east to
central Wisconsin and central Michigan into New York and central
Pennsylvania; then northeastward from Connecticut to the other New England
States. The species is also present locally in the mountains of Virginia
and West Virginia (23,30).
Balsam fir grows from sea level to within 15 to 23 m (50 to 75 ft) below
the 1917 m (6,288 ft) summit of Mount Washington in the White Mountains of
New Hampshire. At this elevation prostrate balsam fir is found in
sheltered areas (1).
- The native range of balsam fir.
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Brief Summary
provided by Silvics of North America
Pinaceae -- Pine family
Robert M. Frank
Balsam fir (Abies balsamea) is one of the more important
conifers in the northern United States and in Canada. Within its range it
may also be referred to as balsam, Canadian balsam, eastern fir, and
bracted balsam fir. It is a small to medium-sized tree used primarily for
pulp and light frame construction, and it is one of the most popular
Christmas trees. Wildlife rely extensively on this tree for food and
shelter.
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