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Wisconsin Plant of the Week

Larix laricina (Du Roi) K. Koch

Pinaceae (Pine Family)

Common Name:

tamarack, American larch


Tamarack is Wisconsinís only native deciduous conifer. It grows in wet to moist organic soils, especially toward the southern edge of its range.  In the cooler north itís also found in drier mineral soils.

Tamarack is a pioneer tree species that requires full sun and wonít regenerate in its own shade. In northern bogs tamarack is associated with, and usually succeeded by, black spruce and other boreal species.  Further south or in calcareous sites itís associated with white cedar and succeeded by lowland hardwoods.

The needle-like leaves reach 2 cm long and grow in two forms -- in clusters of 10 or more on short spur shoots of old wood, and singly on the long branches of the current yearís twig.  The leaves only cast a light shade so trees have a dense undergrowth of shrubs, herbs and mosses.

Tamarack is a straight slender tree to 30 m tall with an open pyramidal crown. Roots are shallow, seldom below 30 cm, and although they generally spread more wide than the tree is tall, mature trees are often lost to windthrow.  As the moss layer builds up under the tree, tamarack forms higher adventitious roots to keep from being submerged.

New cones, that look like deep red miniature roses, flower in April on old wood as the needles begin to elongate. The cones reach 2 cm long and turn brown as they ripen in September. The seeds fall in October as the needles turn yellow.  Empty cones remain on the tree for several years.  First seed production occurs after about 10 years, with large quantities not produced until trees are much older.

Tamarack seed germinates in open sites with lots of light, no competition and constant moisture without flooding.  Fine textured mosses are an ideal substrate. New trees also sprout by layering from branches covered by mosses and from root sprouts several meters from the base of a tree.

Predation, bacteria, fungi, and water level fluctuation contribute to high seedling mortality. Older trees are susceptible to drought and flooding and often die when surface hydrologic conditions change due to road construction or plugged culverts. Insects and disease limit the commercial value of the wood.  Decay resistance due to a high resin content make it unsuitable for pulpwood but useful for posts and timbers.

  • Origin of the name: Larix, L. for larch
  • Range: Atlantic coast to central Alaska, from the northern limit of trees, south to BC, northeast IL, north NJ and locally in mountains further south
  • WI Range:  Statewide, less common south of the Tension Zone
  • Common associates: black spruce, northern white cedar, red maple
  • Wetland Indicator Status: FACW
  • Coefficient of Conservatism: 8 (WI); 10 (S&W); 5 (MI)
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