Larches are medium to large trees of the genus Larix. Scientists debate the finer points of the group’s interrelationships and classification, but most recognize about 10 to 15 species.
Range and Geography
Most larches live in North America, Europe and Asia, although they have been planted in many other locations as ornamental species. Often, these trees are referred to as tamaracks in North America.
Eastern larches (Larix laricina) thrive in moist, acidic soils, while Japanese (Larix kaempferi) and European larches (Larix decidua) thrive in slightly drier soils. Most specimens are best adapted to live at high elevations, and some commonly live at heights of over 7,000 feet.
Description and Characteristics
In many ways, larches are unusual conifers – especially as it relates to their needles. Unlike the spiky or hard leaves of most conifers, larch leaves are soft to the touch. Larches are also deciduous trees that shed their needles each autumn. Like the needles of some other deciduous conifers, such as bald cypresses (Taxodium distichum), larch needles change color before falling off the tree. However, unlike bald cypress needles, which turn reddish-brown before dropping, larch needles turn brilliant yellow in the early autumn.
Additionally, larches produce and bear needles differently than most other conifers. The needles on the current year’s wood emerge singly, whereas those on older wood occur in dense clusters. Stout woody pegs (spur branches) sit at the base of these needle clusters. Larches produce relatively small woody cones, which average about 1 to 2 inches in length.
Larches shed their lower branches as they grow. Mature specimens often feature branchless boles for half or more of their length. Combined with their propensity for producing relatively sparse foliage, their self-pruning nature means that a relatively high level of light penetrates their canopies. This leads to a proliferation of herbaceous and shrubby growth beneath them. The bark of larches is characteristically thin and flaky.
Larches are not especially important food sources for wildlife, although upland game birds and songbirds consume their seeds opportunistically. Birds also make nests in their bushy boughs. Mammals rarely rely on larches for food, but rodents, beavers and other animals occasionally nibble the bark, twigs and buds of the trees.
Most larches need full sun exposure to survive (which is part of the reason they shed their lower, shaded branches). They are very susceptible to competition from other plants, and cannot survive under shaded canopies. Even grasses or other plants growing under their canopies can stress them. Accordingly, larches are early successional species, quickly invading old fields and lakes that have been filled in by silt over the years. Larches often grow as pure stands, but black spruces (Picea mariana) are their primary associate in mixed forests.
Larches typically fare poorly in warm climates, so their use as an ornamental species is primarily limited to northern latitudes. Despite the fact that they often inhabit marshy sites, larches cannot tolerate submerged roots and their shallow rooting habit makes them susceptible to windthrow. While larches often colonize areas following wildfires, their bark provides relatively poor protection from fire.
Larch wood is heavy, strong and relatively resistant to both water and decay. This has led to its use in a variety of applications. One particularly noteworthy use for larch wood is in the production of yachts. However, larches are not very important commercial trees, and most of the harvested trees are converted into pulp.