Larch

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Read about Larch in the Standard Cyclopedia of Horticulture 


Larix (ancient Latin name). Pinaceae. Larch. Tamarack. Ornamental deciduous coniferous trees chiefly grown for their bright or light green foliage and regular habit.

Branches whorled, at least while young:leaves linear, in crowded clusters on short spurs except on the loading shoots where they are spirally arranged: flowers monoecious; staminate flowers small, globose to oblong; solitary, consisting of numerous short-stalked, spirally arranged anthers; pistillate fls. larger, consisting of several or numerous scales, with 2 naked ovules at the base, each scale borne in the axil of a much longerbract: cone with woody, 2-seeded scales, persistent on the axis; seeds with large, thin wings, ripening the first year.— About 10 or 12 species in the colder regions and the high mountains of the northern hemisphere.

The larches are handsome trees of regular pyramidal habit, but in old age becoming sometimes irregular;they are particularly handsome in spring with their light green tender foliage and studded with their usually bright purple pistillate flowers. They are all hardy North except the Himalayan L. Criffithii, and are often planted as park trees, chiefly for the light green foliage and the regular conical, or in some varieties pendulous, habit. The most beautiful is probably L. leptolepis, with the foliage turning bright yellow in fall, while the others assume only a pale yellow color. They are also very valuable forest trees, especially for the northern and mountainous regions; no forest tree goes farther north than the larch, reaching in North America 67° and in Siberia 72° of latitude. The wood is hard, heavy and very durable, and much used for construction, that of L. occidentalis being considered the best of all American conifers. From the European larch turpentine is obtained. The bark contains tannin, and an extract is used for tanning leather. The larch grows in almost any kind of soil, including clay and limestone, and prefers a somewhat moist, but well-drained soil and an open situation; the American larch grows well even in swamps. Unfortunately several insects and fungi prey on the larch, and sometimes do considerable damage, especially the leaf-eating larvae of some moths. Propagation is usually by seeds sown in spring, and the young seedlings shaded; varieties are grafted on seedlings, mostly on those of L. decidua (L.europaea), either outdoors by whip-or cleft-grafting or in the greenhouse by veneer-grafting; they may also be increased by cuttings of nearly ripened wood under glass or by layers, but this method is rarely practised.


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Larch
Larix decidua in autumn
Larix decidua in autumn
Plant Info
Scientific classification
Kingdom: Plantae
Division: Pinophyta
Class: Pinopsida
Order: Pinales
Family: Pinaceae
Genus: Larix
Miller

Species
About 12; see text
Siberian larch
Male (above) and female (below right) cones of Japanese Larch emerging in spring
European Larch foliage and cones

Larches are conifers in the genus Larix, in the family Pinaceae. They are native to much of the cooler temperate northern hemisphere, on lowlands in the far north, and high on mountains further south. Larches are among the dominant plants in the immense boreal forests of Russia and Canada.

They are deciduous trees, growing from 15-50 m tall. The shoots are dimorphic, with growth divided into long shoots typically 10-50 cm long and bearing several buds, and short shoots only 1-2 mm long with only a single bud. The leaves are needle-like, 2-5 cm long, slender (under 1 mm wide). They are borne singly, spirally arranged on the long shoots, and in dense clusters of 20-50 needles on the short shoots. The needles turn yellow and fall in the late autumn, leaving the trees leafless through the winter.

Larch cones are erect, small, 1-9 cm long, green or purple, ripening brown 5-8 months after pollination; in about half the species the bract scales are long and visible, and in the others, short and hidden between the seed scales. Those native to northern regions have small cones (1-3 cm) with short bracts, with more southerly species tending to have longer cones (3-9 cm), often with exserted bracts, with the longest cones and bracts produced by the southernmost species, in the Himalaya.

Species and classification

There are 10-14 species; those marked '*' in the list below are not accepted as distinct species by all authorities. In the past, the cone bract length was often used to divide the larches into two sections (sect. Larix with short bracts, and sect. Multiserialis with long bracts), but genetic evidence (Gernandt & Liston 1999) does not support this division, pointing instead to a genetic divide between Old World and New World species, with the cone and bract size being merely adaptations to climatic conditions. More recent genetic studies have proposed three groups within the genus, with a primary division into North American and Eurasian species, and a secondary division of the Eurasian into northern short-bracted species and southern long-bracted species (Semerikov & Lascoux 1999; Wei and Wang 2003, 2004; Gros-Louis et al. 2005); there is some dispute over the position of Larix sibirica, a short-bracted species which is placed in the short-bracted group by some of the studies and the long-bracted group by others.

Eurasian

Northern, short-bracted

Southern, long-bracted

North American

Most if not all of the species can be hybridised in cultivation. The best known hybrid is the Dunkeld Larch Larix × marschlinsii (syn. L. × eurolepis, an illegitimate name), which arose more or less simultaneously in Switzerland and Scotland when L. decidua and L. kaempferi hybridised when planted together.

Larch is used as a food plant by the larvae of a number of Lepidoptera species - see list of Lepidoptera which feed on Larches.

Larches are prone to the fungal canker disease Lachnellula willkommii (Larch Canker); this is particularly a problem on sites prone to late spring frosts, which cause minor injuries to the tree allowing entry to the fungal spores.

Uses

Larch is a wood valued in for its tough, waterproof and durable qualities; top quality knot-free timber is in great demand for building yachts and other small boats. The hybrid Dunkeld Larch is widely grown as a timber crop in northern Europe, valued for its fast growth and disease resistance.

Larch has also been used in herbal medicine; see Bach flower remedies for details.

In central Europe larch is viewed as one of the best wood materials for the building of residences. Planted on borders with birch, both tree species were used in pagan "sagged" cremations. One "sąg" (pronounced song) of wood was required for a cremation stack. Sąg is used today as a Polish forestry unit measuring approximately 3 × 1 × 1 m.

In Siberia young larch leaves are harvested in spring, preserved by lactobacillus fermentation, and used for salads during winter.

Larches are often used in bonsai culture, where their knobby bark, small needles, fresh spring foliage and especially autumn colour are appreciated. European Larch, Japanese Larch and Tamarack Larch are the species most commonly trained as bonsai.

The tree was a running gag in Monty Python sketches, as in the episode "How to Recognise Different Types of Trees From Quite a Long Way Away".

External links and references

Template:Commonscat Template:Pinaceae

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