Index of Species Information

SPECIES:  Larix laricina


SPECIES: Larix laricina
AUTHORSHIP AND CITATION : Uchytil, Ronald J. 1991. Larix laricina. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: [].
ABBREVIATION : LARLAR SYNONYMS : Larix laricina var. alaskensis (W.F. Wright) Raup SCS PLANT CODE : LALA COMMON NAMES : tamarack Eastern larch Alaskan larch American larch tamarack larch hackmatack TAXONOMY : 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]. LIFE FORM : Tree FEDERAL LEGAL STATUS : No special status OTHER STATUS : NO-ENTRY


SPECIES: Larix laricina
GENERAL DISTRIBUTION : 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. ECOSYSTEMS : FRES10 White - red - jack pine FRES11 Spruce - fir FRES17 Elm - ash - cottonwood STATES : 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 BLM PHYSIOGRAPHIC REGIONS : NO-ENTRY KUCHLER PLANT ASSOCIATIONS : K093 Great Lakes spruce - fir forest K094 Conifer bog K095 Great Lakes pine forest K096 Northeastern spruce - fir forest SAF COVER TYPES : 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 SRM (RANGELAND) COVER TYPES : NO-ENTRY HABITAT TYPES AND PLANT COMMUNITIES : 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


SPECIES: Larix laricina
WOOD PRODUCTS VALUE : 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]. IMPORTANCE TO LIVESTOCK AND WILDLIFE : 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]. PALATABILITY : 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]. NUTRITIONAL VALUE : NO-ENTRY COVER VALUE : 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]. VALUE FOR REHABILITATION OF DISTURBED SITES : 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]. OTHER USES AND VALUES : 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]. OTHER MANAGEMENT CONSIDERATIONS : 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].


SPECIES: Larix laricina
GENERAL BOTANICAL CHARACTERISTICS : 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]. RAUNKIAER LIFE FORM : Phanerophyte REGENERATION PROCESSES : 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. SITE CHARACTERISTICS : 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]. SUCCESSIONAL STATUS : 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]. SEASONAL DEVELOPMENT : 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].


SPECIES: Larix laricina
FIRE ECOLOGY OR ADAPTATIONS : 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". POSTFIRE REGENERATION STRATEGY : off-site colonizer; seed carried by wind; postfire years 1 and 2


SPECIES: Larix laricina
IMMEDIATE FIRE EFFECT ON PLANT : 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. DISCUSSION AND QUALIFICATION OF FIRE EFFECT : NO-ENTRY PLANT RESPONSE TO FIRE : 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]. DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : NO-ENTRY FIRE MANAGEMENT CONSIDERATIONS : 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].


SPECIES: Larix laricina
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Five seasons' growth of conifers. Ecology. 22(3): 285-296. [10909] 6. Cumming, H. G. 1987. Sixteen years of moose browse surveys in Ontario. Alces. 23: 125-156. [8859] 7. Curtis, John T. 1959. The vegetation of Wisconsin. Madison, WI: The University of Wisconsin Press. 657 p. [7116] 8. Damman, A. W. H. 1977. Geographical changes in the vegetation pattern of raised bogs in the Bay of Fundy region of Maine and New Brunswick. Vegetatio. 35(3): 137-151. [10158] 9. Damman, Antoni W. H.; French, Thomas W. 1987. The ecology of peat bogs of the glaciated northeastern United States: a community profile. Biological Report 85(7.16). Washington, DC: U.S. Department of the Interior, Fish and Wildlife Service, Research and Development, National Wetlands Research Center. 100 p. [9238] 10. Dansereau, Pierre. 1959. The principal plant associations of the Saint Lawrence Valley. No. 75. Montreal, Canada: Contrib. Inst. Bot. Univ. Montreal. 147 p. [8925] 11. Duncan, Donald P. 1954. A study of some of the factors affecting the natural regeneration of tamarack (Larix laricina) in Minnesota. Ecology. 35(4): 498-521. [14202] 12. Elliott, Deborah L. 1979. The current regenerative capacity of the northern Canadian trees, Keewatin, N.W.T., Canada: some preliminary observations. Arctic and Alpine Research. 11(2): 243-251. [8419] 13. Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. [905] 14. Famous, Norman C.; Spencer, M. 1989. Revegetation patterns in mined peatlands in central and eastern North America studied. Restoration and Management Notes. 7(2): 95-96. [10171] 15. Farmer, Robert E., Jr.; Reinholt, Ronald W. 1986. Seed quality and germination characteristics of tamarack in northwestern Ontario. Canadian Journal of Forest Research. 16(3): 680-683. [14280] 16. Fowells, H. A., compiler. 1965. Silvics of forest trees of the United States. Agric. Handb. 271. 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Anchorage, AK: U.S. Department of the Interior, Bureau of Land Management, Anchorage District Office. 83 p. [6400] 21. Heinselman, M. L. 1970. Landscape evolution, peatland types and the environment in the Lake Agassiz Peatlands Natural Area, Minnesota. Ecological Monographs. 40(2): 235-261. [8378] 22. Hosie, R. C. 1969. Native trees of Canada. 7th ed. Ottawa, ON: Canadian Forestry Service, Department of Fisheries and Forestry. 380 p. [3375] 23. Jeglum, John K. 1971. Plant indicators of pH and water level in peatlands at Candle Lake, Saskatchewan. Canadian Journal of Botany. 49: 1661-1676. [7450] 24. Johnston, William F. 1973. Tamarack seedlings prosper on broadcast burns in Minnesota peatland. Res. Note NC-153. St. Paul, MN: U.S. Department of Agriculture, Forest Service, North Central Forest Experiment Station. 3 p. [12802] 25. Johnston, William F. 1975. Reproducing lowland conifer forests. Journal of Forestry. 73: 17-20. [14277] 26. Johnston, William F. 1990. Larix laricina (Du Roi) K. Koch tamarack. In: Burns, Russell M.; Honkala, Barbara H., technical coordinators. Silvics of North America. Volume 1. Conifers. Agric. Handb. 654. Washington, DC: U.S. Department of Agriculture, Forest Service: 141-151. [13379] 27. Johnston, William F.; Brittain, Robert E. 1983. Tamarack. In: Burns, Russell M., technical compiler. Silvicultural systems for the major forest types of the United States. Agric. Handb. No. 445. Washington, DC: U.S. Department of Agriculture, Forest Service: 99-101. [25102] 28. Johnston, William F.; Carpenter, Eugene M. 1985. Tamarack: An American wood. FS-268. Washington, D.C.: U.S. Department of Agriculture, Forest Service. 7 p. [9119] 29. Kuchler, A. W. 1964. Manual to accompany the map of potential vegetation of the conterminous United States. Special Publication No. 36. New York: American Geographical Society. 77 p. [1384] 30. Lieffers, Victor J.; MacDonald, S. Ellen. 1990. Growth and foliar nutrient status of black spruce and tamarack in relation to depth of water table in some Alberta peatlands. Canadian Journal of Forestry Research. 20: 805-809. [11804] 31. Lieffers, V. J.; Rothwell, R. L. 1987. Rooting of peatland black spruce and tamarack in relation to depth of water table. Canadian Journal of Botany. 65: 817-821. [19931] 32. Little, Elbert L., Jr. 1979. Checklist of United States trees (native and naturalized). Agric. Handb. 541. Washington, DC: U.S. Department of Agriculture, Forest Service. 375 p. [2952] 33. Lyon, L. Jack; Stickney, Peter F. 1976. Early vegetal succession following large northern Rocky Mountain wildfires. In: Proceedings, Tall Timbers fire ecology conference and Intermountain Fire Research Council fire and land management symposium; 1974 October 8-10; Missoula, MT. No. 14. Tallahassee, FL: Tall Timbers Research Station: 355-373. [1496] 34. Martin, Alexander C.; Zim, Herbert S.; Nelson, Arnold L. 1951. 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