American Larch

tamarack
Eastern larch
Alaskan larch
American larch
tamarack larch
hackmatack

More info for the term: cover

Tamarack is probably of limited value as cover for mammals and birds
because it sheds its needles in the winter and often occurs in rather
open stands. In northern Minnesota, ospreys prefer to nest in dead
tamarack trees. Bald eagles occasionally nest in tamarack [35].

More info for the term: tree

Tamarack is a native, deciduous, coniferous, small- to medium-sized
upright tree. It has a straight bole with a narrow pyramidal crown.
Tamarack is a good self-pruner and by 25 to 30 years of age, trees are
generally clear of branches for one-half to two-thirds of their bole
[26]. Trees generally reach 50 to 75 feet (15-23 m) in height and 14 to
20 inches (46-51 cm) d.b.h. but are occasionally larger. In Alaska,
trees are often stunted, reaching heights of only 10 feet (3 m) and
diameters of 3 inches (8 cm), but on good sites mature trees are
generally 30 to 60 feet (9-18 m) tall and 4 to 10 inches (10-25 cm)
d.b.h. [26,49]. The maximum age for tamarack is about 180 years,
although older trees have been found [26].

Tamarack has 1-inch-long (2.5 cm) needles that occur in clusters of 10
to 20 on dwarf twigs [22] and turn yellow in the fall before they are
shed. Erect mature cones are about 0.5 to 0.75 inch (1.3-1.9 cm) long
[26]. Tamarack bark is smooth when young but becomes rough and scaley
on older trees. The bark is thin, only about 0.25 to 0.5 inch (0.6-1.2
cm) thick on mature trees [28]. The root system is typically shallow
and wide spreading. Rooting depth rarely exceeds 1.5 feet (46 cm), but
the roots commonly spread over areas greater in radius than the tree
height [7]. On wet and very wet peatlands in Alberta, roots are
generally restricted to the upper 8 inches (20 cm) of soil on hummocky
positions [31].

Tamarack is distributed across most of northern North America. It
occurs from Newfoundland and Labrador northwest across northern Canada
to the northern Yukon Territory, south to northeastern British Columbia
and central Alberta, southeast to southern Minnesota, Wisconsin, and
northeastern Illinois, and east to New England [32]. A major disjunct
population occurs in the interior of Alaska between the Brooks Range to
the north and Alaska Range to the south [26]. It also occurs locally in
the mountains of West Virginia and western Maryland.

More info for the terms: fire regime, seed

Tamarack trees are easily killed by fire. The species relies on seed
from surviving trees to revegetate burned areas. Generally found in
boggy and swampy habitats, pockets of tamarack trees often escape
burning due to local topography or extremely wet conditions. These
trees provide seeds for postfire recovery. Because seed is dispersed
over short distances, tamarack is not well adapted to rapid reseeding of
large burns.

FIRE REGIMES :
Find fire regime information for the plant communities in which this
species may occur by entering the species name in the FEIS home page under
"Find FIRE REGIMES".

More info for the term: shrubs

Tamarack establishes readily on sites where logging slash is burned but
poorly on sites where slash is untreated. On peatlands in Minnesota,
tamarack seedlings were abundant 6 years following broadcast burning of
black spruce-tamarack slash in clearcuts [24]. However, pure tamarack
slash is difficult to broadcast burn. Therefore, when cutting pure
tamarack stands, piling and burning slash is the option that best favors
tamarack reproduction [25].

In Wisconsin, prescribed burning has been conducted in conifer swamps
and muskegs to improve wildlife habitat. Prescribed burning killed
tamarack and other conifers in swamps, and improved feeding and nesting
habitat for game birds by converting these areas to swamps dominated by
sedges (Carex spp.) and ericaceous shrubs [50].

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More info for the term: phanerophyte

Phanerophyte

More info for the terms: bog, minerotrophic, organic soils, peat, peatland, permafrost, shrub, shrubs, swamp, tree

Tamarack is most commonly found on cold, wet to moist, poorly drained
sites such as swamps, bogs, and muskegs [22,26,44]. It is also found
along streams, lakes, swamp borders, and occasionally on upland sites.
It becomes more common on drier sites in the northern portion of its
range where it is found on ridges and benches and other upland locations
[26]. In British Columbia, it grows as an upland tree on cool, moist
north slopes as well as on wet organic sites [26]. In interior Alaska,
tamarack is generally restricted to wet and cold sites underlain by
shallow permafrost but occasionally grows in warmer, well-drained
floodplains and upland forests dominated by white spruce (Picea glauca)
[4].

Soils: Tamarack can tolerate a wide range of soil conditions but most
commonly grows on wet to moist organic soils, such as sphagnum or woody
peat, and is especially common on nutrient-poor, acid peatlands [9,26].
In Minnesota, tamarack occurs on a wide variety of peatland types, from
rich swamps to raised bogs, and is an indicator of weakly minerotrophic
sites (pH 4.3-5.8, Ca 3-10 ppm, Ca + Mg 5-13 ppm) [21]. In
Saskatchewan, tamarack grows on peatland sites with a wide range of
fertility and moisture regimes; it is most common on those with a pH
between 6.0 and 6.9 [23]. Although most commonly occurring on
peatlands, tamarack actually grows best on well-drained loamy soils
along streams, lakes, and seeps, and on mineral soils with a shallow
surface layer of organic matter [26]. However, tamarack is uncommon on
these sites in the southern portion of its range because it is easily
outcompeted by other trees. It is more common on mineral soil in the
north.

Stand characteristics and associated trees: Because the species is
intolerant of shade, tamarack stands are usually even-aged [13]. They
occur on wetter sites than black spruce stands. Across tamarack's range
black spruce is its most common associate. These two species often form
mixed stands on peatlands. Throughout much of boreal Canada, other
associates include balsam fir (Abies balsamea), white spruce, paper
birch (Betula papyrifera), and quaking aspen (Populus tremuloides)
[22,26]. In the Lake States and New England, common associates include
northern white-cedar (Thuja occidentalis), balsam fir, eastern white
pine (Pinus strobus), red pine (P. resinosa), quaking aspen, black ash
(Fraxinus nigra), white spruce, and red maple (Acer rubrum) [7,44]. In
Alaska, tamarack is usually found with black spruce and paper birch but
almost never with aspen [26].

Understory: Tamarack stands tend to cast light shade and have a dense
undergrowth of shrubs. Tall shrubs associated with tamarack include bog
birch (Betula glandulosa), swamp birch (B. pumila), speckled alder
(Alnus incana ssp. rugosa), willows (Salix spp.), and red-osier dogwood
(Cornus stolonifera). Low shrub associates include Labrador-tea (Ledum
groenlandicum), bog-rosemary (Andromeda glaucophylla), leatherleaf
(Chamaedaphne calyculata), and blueberries and huckleberries (Vaccinium
spp.). The ground is usually covered with sphagnum and other mosses
[26].

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This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

1 Jack pine
5 Balsam fir
12 Black spruce
13 Black spruce - tamarack
33 Red spruce - balsam fir
37 Northern white cedar
38 Tamarack
39 Black ash - American elm - red maple
107 White spruce
201 White spruce
203 Balsam poplar
204 Black spruce
253 Black spruce - white spruce
254 Black spruce - paper birch

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This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

FRES10 White - red - jack pine
FRES11 Spruce - fir
FRES17 Elm - ash - cottonwood

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This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

More info for the terms: bog, forest

K093 Great Lakes spruce - fir forest
K094 Conifer bog
K095 Great Lakes pine forest
K096 Northeastern spruce - fir forest

More info for the terms: muskeg, seed, surface fire

Tamarack is easily killed by fire because it has thin bark and shallow
roots. On peatlands it is usually killed by all but very light surface
fires [26]. Tamarack seeds have no endosperm to protect them from high
temperatures; therefore, seeds on the ground are usually destroyed by
fire. Cones are not necessarily destroyed by summer fires, but immature
seeds will not ripen on fire-killed trees [52]. If summer fires kill
tamarack trees over extensive areas, no seed will be available to
revegetate the burned area.

Following a fire in a northern Wisconsin muskeg all tamaracks died
(trees were 1 to 5 inches [2.5-12.5 cm] d.b.h.) [50]. In interior
Alaska, all tamarack trees died following a low-intensity surface fire
that burned only 2 to 4 inches (5-10 cm) into the organic mat [20].
These trees were 49 to 79 years old and 1.5 to 3 inches (3-6 cm) in
diameter.

More info for the term: seed

Browse: Tamarack is an important dietary component of very few wildlife
species. It is browsed by some animals but generally to a limited
extent. Snowshoe hares feed on twigs and bark, and porcupines feed on
the inner bark [16]. Moose and white-tailed deer generally avoid
tamarack [6,16]. Spruce, blue, and sharp-tailed grouse readily consume
the needles and buds [34,51]. A study in north-central Canada found
that caribou consume small amounts of tamarack; needles were frequently
found in caribou rumens, but always in small amounts [36].

Seed: Red squirrels cut and cache tamarack cones. The pine siskin,
crossbills, and probably other seed eating birds eat tamarack seeds
[19]. Mice, voles, and shrews consume large numbers of tamarack seeds
off the ground [11].

More info for the terms: bog, forest, permafrost, tree

In northern Minnesota and throughout much of Canada, tamarack forms
extensive pure stands. Throughout the rest of its range in the United
States it forms isolated pure stands or is a minor component of other
forest types [26]. In the northeastern United States, tamarack is
characteristically found in open and forested bogs, but it seldom
dominates in forested bog communities [9]. Throughout its range, black
spruce (Picea mariana) is usually associated with tamarack. In Alaska,
black spruce and tamarack may codominate wet, lowland sites with shallow
permafrost [48].

Tamarack is sometimes a dominant tree in seral lowland communities. It
has been listed as a community type (cts) dominant in the following
classifications:

Area Classification Authority

AK general veg. cts Viereck & Dyrness 1980

AB general veg. cts Moss 1955
PQ: ST. Lawrence general veg. pas, cts Dansereau 1959
Valley

More info for the term: tree

Tree

Silviculture: Tamarack seeds germinate and establish best in the open.
Seedlings require nearly full sunlight to survive and grow well.
Consequently, even-age silviculture is best for perpetuating larch on a
site [2,27].

Insects and diseases: Larch sawfly is the most destructive pest of
tamarck. Epidemics occur periodically in tamarack stands across the
northern United States and Canada. This insect is capable of
defoliating stands over large areas and killing many trees. Trees die
after 6 to 9 years of heavy defoliation [26]. Outbreaks of the larch
casebearer have also caused extensive mortality in some areas. The
spruce budworm, larch bud moth, spruce spider mite, larch shoot moth,
and several bark beetles also infest tamarack but seldom cause serious
injury [26]. Tamarack is generally resistant to rusts and other
diseases [26].

Flooding: Tamarack is susceptible to damage from flooding and
disruptions in groundwater movements. Trees have been killed over large
areas where newly constructed roads impede water movements and where
beavers dam drainage ditches or small streams [26].

AK CT IL IN ME MD MA MI MN NH
NJ NY OH PA VT WV WI AB BC LB
MB NB NF NS ON PE PQ SK YT

In Alaska, young tamarack stems are used for dogsled runners, boat ribs,
and fishtraps. In northern Alberta, duck and goose decoys are made from
tamarack branches. Indians used the roots for cordage, the wood for
arrow shafts, and the bark for medicine. Early Americans used the soft
needles for stuffing pillows and mattresses and used the roots of large
trees for ship building [26,28].

The palatability of tamarack for white-tailed deer and moose is low.
Tamarack is more palatable to snowshoe hare than white spruce (Picea
glauca) is [4].

More info on this topic.

More info for the term: seed

Minnesota: Buds begin to swell from early to late April. Needles begin
to emerge from about mid-April to mid-May. Needles are shed from
mid-September to mid-October. Flowering occurs from late April to early
May. Seedfall begins in early September and is nearly complete by late
October [11,16,26].

Wisconsin: Tamarack begins to leaf out in the early spring before the
ground has thawed. It takes 4 to 6 weeks for the needles to develop
fully. The needles turn yellow in late September or early October and
are shed shortly thereafter [7].

Upper Peninsula of Michigan: Needles begin to emerge in mid-April to
mid-May. Needles begin to turn yellow in early September and are shed
from mid-September to mid-October. Flowering occurs in early May, and
cones are ripe by late August [16,26].

Alaska: Seed dispersal begins in early September and is mostly
completed by late October [4].

New York: Height growth begins in late May and ends by late August [5].

More info for the terms: seed, swamp, tree

Following fire, tamarack reestablishes via wind-dispersed seeds from
surviving trees in protected pockets or adjacent unburned areas. Burned
organic surfaces favor seedling establishment. Within a few years
tamarack reproduction is often localized and centered around areas of
surviving trees [37].

In northeastern British Columbia, tamarack seeded onto burned areas over
several years. Most seedlings established within 10 years after fire,
but additional establishment continued until 20 years after fire [41].
Postfire tamarack seedlings grow rapidly. Twenty-one years after a fire
in a tamarack-black spruce swamp in northeastern British Columbia,
tamarack seedlings were more than 2 times taller than black spruce
seedlings. Tamarack seedlings that established soon after the fire
averaged 7.9 feet (2.4 m) tall, while black spruce seedlings that
established at the same time were only 3.6 feet (1.1 m) tall [40].

Tamarack seedlings were abundant 6 years after clearcutting and
broadcast burning in mixed black spruce-tamarack stands in northern
Minnesota. Tamarack seedlings made up 43 percent of tree seedlings 66
feet (20 m) downwind from the uncut border, even though tamarack made up
only 27 percent of the seed trees (55 per acre [136/ha]). On this site,
4,200 tamarack seedlings averaging 21 inches (53 cm) in height were
established per acre (10,400/ha). On another cut where there were only
12 tamarack seed trees per acre (30/ha) at the uncut border, 4,400
seedlings averaging 39 inches in height (1 m) were established per acre
(10,900/ha) [24].

More info for the term: seed

off-site colonizer; seed carried by wind; postfire years 1 and 2

More info for the terms: cone, layering, litter, seed, tree, tussock

Cone and seed production: Cone production begins at about 15 years of
age for open-grown trees and 35 to 40 years of age for trees in
well-stocked stands [11]. Large quantities of seed are usually not
produced until trees are at least 40 years old. Fifty- to 150-year-old
open-grown trees produce the best cone crops, with individual trees
sometimes producing as many as 20,000 cones in a good year [11]. Good
seed crops are produced every 3 to 6 years, with some seed produced in
intervening years. Tamarack seeds are about 0.12 inch (3 mm) long and
have a wing about 0.25 inch (6 mm) long [26].

Dispersal: Seeds are dispersed in the fall over a relatively short time
period. In a Minnesota study, dispersal began about September 1, and by
October 31 about 98 percent of seed had fallen [11]. The remaining seed
fell throughout the winter. In interior Alaska, 95 percent of tamarack
seeds are shed by November [4]. Tamarack seeds are primarily wind
dispersed, but red squirrels disperse some seed. Most wind-dispersed
seeds fall within a distance of two tree heights, but a small percentage
travels greater distances [4,11].

Seed destruction and predation: In Minnesota, small mammals, presumably
mice, voles, and shrews, consume large quantities of tamarack seed off
the ground and can destroy up to one-half of a tamarack seed crop [11].
Also, seeds on the ground are susceptible to infections from bacteria
and fungi. Consequently, only about 4 or 5 percent of tamarack seed
that reaches the ground germinates [26]. In tamarack stands in New
Brunswick, insects destroyed between 25 and 88 percent of seed produced.
Larvae of the spruce budworm and the cone maggot were responsible for
greatest loss [53].

Viability: Tamarack seed remains viable for only about 1 year after
dispersal [11]. Typically a large percentage of tamarack seed is
unfilled. In Minnesota about one-third, and in northern Ontario about
one-half of seed had undeveloped embryo and endosperm [11,15]. At the
northern portion of the species range in the Northwest Territories,
tamarack produced a limited amount of seed, but none was viable [12].

Germination and establishment: Germinative capacity ranges from about
30 to 60 percent [11]. Neither light nor pH appear to influence
germination appreciably [11,15]. Tamarack seeds require a moist but
unsaturated substrate for germination. The best seedbed is warm, moist
mineral or organic soil free from competing vegetation [26].
Slow-growing sphagnum mosses also provide a good seedbed, as they have a
tendency to remain moist. In open swampy habitats, tamarack seedlings
are often found on sphagnum mosses [1,7]. Feather mosses are usually
poor seedbeds because they tend to dry out, but if they remain moist,
they can provide a favorable seedbed [4]. On poorly drained river
terraces in interior Alaska, tamarack seedlings are more abundant on
sphagnum and feather mosses than on sedge tussock tops, troughs between
the tussocks, or litter-covered sites; on well-drained river terraces,
seedlings are primarily restricted to mineral soil [4]. Tamarack
seedlings are intolerant of shade and flooding. Seedlings may survive a
few years in shade, but most will die unless released. Partial water
submersion for 1 to 3 weeks kills 1st-year seedlings [11]. In full
sunlight seedlings grow relatively rapidly, reaching heights of 7 to 9
inches (18-23 cm) after one growing season, and 18 to 25 inches (46-51
cm) tall after three [26]. Roots of seedlings growing in nearly full
sunlight may reach depths of 2.5 to 3.5 inches (5-11 cm) after one
growing season, while over the same time period roots of seedlings
growing in shade reach depths of only about 1 inch (2.5 cm) [11].

Vegetative reproduction: Layering is a dominant mode of reproduction at
the northern limit of the species' range. In the southern part of its
range, layering is uncommon but does occur when lower branches become
covered with litter or fast-growing mosses [26]. Curtis [7] reported
that tamarack has the unusual ability to produce root sprouts up to 30
feet (9 m) away from a mother tree.

More info on this topic.

More info for the terms: peat, shrub, swamp, tree

Tamarack is a pioneer or early seral species. It is often the first
tree to invade open bogs and burned peatlands [26]. In open bogs and
swamps, tamarack is the first tree to pioneer the sphagnum moss mat
floating over water [7]. This invasion toward the center or wettest
portion of a swamp is common [1,18]. It may invade bogs during sedge
mat, sphagnum moss, or ericaceous shrub stages. Tamarack is extremely
intolerant of shade, however, and eventually, as the peat becomes
consolidated and firm, other conifers replace it. It is replaced by
black spruce on poorly drained acid peatlands. In nutrient-rich swamps
it is replaced first by black spruce, and later by northern white-cedar,
balsam fir, and eventually swamp hardwoods [16].

Larix laricina var. alaskensis (W.F. Wright) Raup

More info for the terms: cone, natural

The currently accepted scientific name of tamarack is Larix laricina (Du
Roi) K. Koch [32]. The genus Larix consists of 10 species of deciduous,
coniferous trees found in cool, temperate regions of the northern
hemisphere. Three species of Larix, including tamarack, are native to
North America.

Tamarack is a widely distributed species that exhibits considerable
genetic variation. At one time, plants from Alaska were considered as
either a distinct species or as a variety of tamarack. Recent research
shows that although Alaskan plants exhibit some variation in cone and
needle characteristics, the variation is insufficient to warrant
recognition as a separate species or variety [39]. Across tamarack's
range the pattern of variation is gradual, and no varieties or ecotypes
are currently recognized [26].

Natural hybridization between tamarack and other larches has not been
documented. Tamarack has been artificially crossed with Japanese larch
(L. leptolepis) and European larch (L. decidua) [26].

More info for the term: seed

Tamarack may be useful for revegetating disturbed peatlands. In
southeastern Canada, Maine, and Minnesota, tamarack naturally invades
well-drained, raised surfaces in abandoned mined peatlands [14].
Tamarack should not be planted with fast-growing trees because of its
low tolerance for shade.

On amended sand tailings in northern Alberta, tamarack survival varied
from 0 to 60 percent [51]. When planted on coal mine spoils it
performed quite well. It grew faster than black spruce and added needed
organic matter to the spoil [51].

Tamarack can be established on disturbed sites by direct seeding or by
transplanting seedlings. Tamarack seed does not exhibit dormancy and
can be planted in the spring or fall. Seed should be sown at a depth of
about 0.25 inch (0.6 cm). Seed remains viable for 4 years when kept in
sealed containers at 18 to 22 degrees F (-8 to -6 C) and a seed moisture
content of 2 to 5 percent [45]. Tamarack is easily propagated from
cuttings taken from young trees [26,54].

Tamarack is not a major commercial timber species. In the United
States, it is primarily used for pulpwood. Because the wood is heavy,
durable, and decay-resistant, it is also used for posts, poles, mine
timbers, and railroad ties. It is used less commonly for rough lumber,
fuelwood, boxes, crates, and pails [28].