BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Abies balsamea | Balsam Fir 



GENERAL BOTANICAL CHARACTERISTICS : 
Balsam fir is a native, coniferous, evergreen, small to medium-sized,
upright tree.  At maturity it may reach a height of 40 to 90 feet (12-27
m) and a d.b.h. of 12 to 30 inches (30-75 cm) [5].  Maximum age is about
200 years.  Balsam fir has a dense, narrowly pyrimidal crown terminating
in a slender, spirelike top.  Open-grown trees may have live branches
extending to the ground, but trees in well-stocked stands have dead,
persistent lower branches [29].  The needles are flat, resinous, and 0.4
to 1.2 inches (1-3 cm) long [5].  Erect cones occur on the upper side of
1-year-old branches in the upper crown.  The bark is gray and smooth and
contains numerous raised resin blisters.  On older trees the bark
becomes brown and scaly but is less than 0.5 inch (1.2 cm) thick [5].
Balsam fir has a shallow root system that is mostly confined to duff and
upper mineral soil layers.  Roots rarely penetrate more than 30 inches
(75 cm) below the ground surface, except in sandy soils [21].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Seed production and dispersal:  Balsam fir is a prolific seed producer.
Seed production begins when plants are about 20 years old or 15 feet
tall [5], and regular seed production occurs after trees are about 30
years old.  Some seed is produced every year, with heavy seed crops
occurring at 2- to 4-year intervals [21].  Most seeds are shed in
autumn, but small amounts fall throughout the winter and into spring
[21].  The winged seeds are primarily dispersed by wind.  Most fall
within 80 to 200 feet (25-60 m) of the tree, but some travel up to 525
feet from the tree (160 m) [21].  Some seed is dispersed by small
mammals.

Only about 50 percent of balsam fir seeds are sound [24].  Germinative
capacity is relatively low, ranging from about 20 to 50 percent [5].
Seeds remain viable for less than 1 year under natural conditions [21].

Germination and seedling establishment:  Most seeds germinate between
late May and early July [21].  If moisture is sufficient, seedlings will
establish on almost any substrate, but establishment is generally best
on mineral soil.  Other good seedbeds include rotting wood embedded in
humus because it can remain moist even during prolonged drought, and
rotting logs and stumps because they have a tendency to shed hardwood
leaf litter which can smother seedlings [36].  Hardwood leaf litter is a
poor seedbed; seedlings on deep layers of hardwood litter usually die
within a few weeks of germination [5].  However, balsam fir establishes
more readily on shallow litter (less than 3 inches [7.5 cm]) than other
conifers because seedlings quickly develop a deep root system [21].
Seedlings are very shade tolerant.  Once established they can withstand
many years of suppression.

Vegetative reproduction:  Layering occurs in swamps and mossy areas, and
under white and jack pine (Pinus strobus, P. banksiana) overstories [5].
In the White Mountains of New Hampshire, prostrate balsam fir above
5,500 feet (1,700 m) in elevation reproduce almost entirely by layering
[5].


SITE CHARACTERISTICS : 
Balsam fir grows on a wide variety of upland and lowland sites.  It
occurs on mountain slopes and glaciated uplands as well as on alluvial
flats, peatlands, and swamps.  It is found in pure, mixed coniferous,
and mixed coniferous-deciduous stands.

Soils:  Balsam fir grows on sites underlain by a variety of parent
materials, including gneiss, schist, anorthosite, diabase, slate,
sandstone, and limestone.  It grows mostly on acid Spodosol, Inceptisol,
and Histisol soil orders [21].  It grows on all soil textures, from
heavy clay to rocky.  It tolerates a wide range of soil acidity.  In the
Lake States, balsam fir is most common on cool, wet-mesic sites with
soil pH values between 5.1 and 6.0 [21].  In northeast Wisconsin it
commonly grows on limestone outcrops [45].

Associated trees:  Associated trees of uplands include white spruce, red
spruce, paper birch, aspen, white ash (Fraxinus americana), yellow birch
(Betula alleghaniensis), American beech (Fagus grandifolia), red maple,
sugar maple (Acer saccharum), eastern hemlock, and white pine.  Lowland
associates are black spruce, white spruce, tamarack (Larix laricina),
red maple, black ash (Fraxinus nigra), and northern white-cedar [17].

Understory:  Common shrub associates include beaked hazel (Corylus
cornuta), bog Labrador-tea (Ledum groenlandicum), mountain maple (Acer
spicatum), Canada yew (Taxus canadensis), red raspberry (Rubus idaeus),
sheep laurel (Kalmia angustifolia), and hobblebush (Viburnum
lantanoides) [21].

Elevation:  Balsam fir grows from near sea level along the Atlantic
seaboard to timberline at 5,600 feet (1,700 m) in the Appalachian
Mountains, and to 6,200 feet (1,890 m) in the White Mountains in New
Hampshire [21].


SUCCESSIONAL STATUS : 
Balsam fir is a late successional or climax species.  Following fire, it
is replaced by pioneering hardwoods and conifers, such as aspen, paper
birch, balsam poplar (Populus balsamifera), jack pine, and black spruce.
Except for scattered survivors, it is mostly absent for the first few
postfire decades.  In Ontario, balsam fir seedlings often first appear
under aspen-birch-spruce types 30 to 50 years after fire [5,36].  Balsam
fir seedlings are shade tolerant and less exacting in seedbed
requirements than many associates.  It readily establishes under a
canopy of hardwoods and conifers.  In the Lake States, an understory of
balsam fir seedlings is almost ubiquitous in several upland and lowland
forests [30].  In boreal forests, it is usually a common understory
component beneath pines, aspen, and paper birch [7,15,28].  In the
continued absence of fire, balsam fir may assume dominance as the canopy
of the pioneering trees begins to break up.

In the Lake States, balsam fir can become climax on poorly drained clay
soils.  It often succeeds aspen, paper birch, and sometimes black spruce
[17].  On mesic sites, it is often replaced by shade-tolerant hardwoods
such as sugar maple [30].


SEASONAL DEVELOPMENT : 
Phenological events proceed as follows [5]:

  Event             Southern part of range      Northern part of range

flowering begins        early May                  early June
seeds ripen             late August-early Sept.    October
seedfall begins         early September            October

Related categories for Species: Abies balsamea | Balsam Fir