Trees and Shrubs Larch – Larix / European Larch – Larix decidua
Larches are conifers in the genus Larix, in the family Pinaceae. Growing from 20 to 45 m tall (65 to 147 ft), they are native to much of the cooler temperate northern hemisphere, on lowlands in the north and high on mountains further south.
Although a conifer, the larch is a deciduous tree and loses its leaves in the autumn.
Larix decidua, common name European larch, is a species of larch native to the mountains of central Europe.
It is thought to have been first cultivated in Britain in 1629. John Evelyn encouraged its wider planting and use. Three successive Dukes of Atholl planted it widely and the fourth Duke wrote “Observations on Larch” in 1807 encouraging further its cultivation, which he practiced on a large scale.
Larch – Larix – general details.
The shoots are dimorphic, with growth divided into long shoots typically 10–50 centimetres 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 centimetres long, slender (under 1 cm 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 exerted bracts, with the longest cones and bracts produced by the southernmost species, in the Himalayas.
Species and classification
There are 10–15 species; those marked with an asterisk (*) 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 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; 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.
- Larix decidua (syn. L. europaea) European larch. Mountains of central Europe.
- Larix sukaczewii Russian larch.* Russia west of Ural Mountains.
- Larix sibirica Siberian larch. Plains of western Siberia.
- Larix gmelinii (syn. L. dahurica) Dahurian larch. Plains of central and eastern Siberia.
- Larix kaempferi (syn. L. leptolepis) Japanese larch. Mountains of central Japan.
- Larix principis-rupprechtii Prince Rupprecht’s larch. Mountains of northern China (Shanxi, Hebei).
- Olgan larch or Olga Bay larch (Larix gmelinii var. olgensis) is sometimes treated as a distinct species Larix olgensis.
- Larix potaninii Chinese larch. Mountains of southwestern China (Sichuan, northern Yunnan).
- Larix himalaica Langtang larch.* Mountains of central Himalayas.
- Larix mastersiana Masters’ larch. Mountains of western China.
- Larix speciosa Yunnan larch.* Mountains of southwest China (southwest Yunnan), northeast Burma.
- Larix griffithii (syn. L. griffithiana) Himalayan larch. Mountains of eastern Himalaya
- Larix laricina Tamarack larch or American larch. Parts of Alaska and throughout Canada and the northern United States from the eastern Rocky Mountains to the Atlantic shore.
- Larix lyallii Subalpine larch. Mountains of northwest United States and southwest Canada, at very high altitude.
- Larix occidentalis Western larch. Mountains of northwest United States and southwest Canada, at lower altitudes.
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.
Species which feed exclusively on Larix
- Several Coleophora case-bearer species:
- C. laricella (Larch Casebearer) – only on European Larch (L. decidua)
- C. obducta
- C. sibiricella – only on European Larch (L. decidua)
- Several Coleophora case-bearer species:
- Chionodes tragicella
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. In Canada, this disease was first detected in 1980 and is particularly harmful to an indigenous species larch, the tamarack, killing both young and mature trees.
Larches are also vulnerable to Phytophthora ramorum. In late 2009 the disease was first found in Japanese larch trees in the English counties of Devon, Cornwall and Somerset, and has since spread to the south-west of Scotland. In August 2010 the disease was found in Japanese larch trees in counties Waterford and Tipperary in Ireland and in 2013 in the Afan Forest Park in south Wales.
Larch is a wood valued for its tough, waterproof, and durable qualities; top quality knot-free timber is in great demand for building yachts and other small boats, for exterior cladding of buildings, and interior panelling. The timber is resistant to rot when in contact with the ground, and is suitable for use as posts and in fencing. The hybrid Dunkeld larch is widely grown as a timber crop in northern Europe, valued for its fast growth and disease resistance. (EN 350-2 lists larch as slightly to moderately durable, this would make it unsuitable for ground contact use without preservative in temperate climates, and would give it a limited life as external cladding without coatings).
Larch has also been used in herbal medicine; see Bach flower remedies and Arabinogalactan 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 cremations.
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.
Often, in Eurasian shamanism, the “world tree” is depicted as specifically a larch tree.
image CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=948814
Edward Step included the following in his Wayside and Woodland Trees from the 19th century when the classification was given as Larix europæa.
The Larch (Larix europæa).
An enormous number of exotic Coniferous trees are at the present time commonly grown in our parks and pleasure grounds, and even our woods show a considerable variety beyond the Scots Pine and Yew that Nature has alone given us as timber trees in this order. To attempt to give even a very brief account of all these in a pocket volume, in addition to almost the entire woody Flora indigenous to these islands, would be manifestly absurd. We can, however, deal with a few representative species of these exotics, and we give the Larch the first place by reason of its present plentifulness in extensive unmixed woods and plantations.
The Larch is naturally a tree of the mountains, and ascends to a greater elevation even than the Spruce Fir. Unmixed forests of Larch in the Bavarian Alps occur between 3000 and 6000 feet above sea-level, and on the central Swiss Alps it ascends to nearly 7000 feet. A long winter of real cold is necessary for its full development and the ripening of its wood, and for that reason the timber of Larch grown in England is inferior to that grown in its native countries, because our winters are either short or mild, and neither gives the tree the full rest it needs. It is a European tree, and was introduced—though not in any numbers—to England at some date prior to 1629. For 150 years it appears to have been cultivated here merely as an ornamental garden tree. Then attention was called to its value as a timber tree, and the Society of Arts offered gold medals for Larch planting and essays upon its economic importance. Already (1728) the second Duke of Atholl had begun those experiments in Larch growing for timber which have been continued by his successors on a vast scale, the fourth Duke planting 27,000,000 Larch-trees on 15,000 acres of barren land. Their example has been copied on a smaller scale all over the country.
The Larch is a lofty tree, with a very straight tapering trunk ordinarily attaining a length between 80 and 100 feet, but under very favourable conditions 120 feet, with a girth of bole from 6 to 12 feet. The brown bark is easily separable into thin layers, and the growth of the tree causes it to split into deep longitudinal fissures. The long lower branches are spreading, with a downward tendency, and the tips turned upward again. The twigs are mostly pendulous, and bear long and slender light-green leaves, in bundles of thirty or forty. All the other families of Coniferous trees are evergreen, their leaves lasting for several years; but at the beginning of winter the Larch leaves wither and fall, and the Larch-wood takes on a more lifeless aspect than is assumed by any of our native trees in their leafless condition. But in spring, when the fresh green leaves are just showing in spreading tufts, and the reddish-purple female flowers—Tennyson’s “rosy plumelets”—hang brightly from the gaunt branches, the Larch wears an entirely different appearance, and in summer the light grace of branches and foliage makes the Larch a beautiful object. That is, one should say, the trees that grow on the very outer edge of the wood, or, better still, one that has been planted as a specimen tree, where it has room to fling out its arms on all sides without touching anything, and can get the abundant light it needs. The straight rows in the plantation, with every tree at an equal distance from its neighbours, and its lower branches dead, may be very pretty from the timber-merchant’s point of view, but one likes to think of the tree as a living thing of beauty rather than as a detail in a factory where scaffold-poles and telegraph-posts are being grown to regulation size and shape.
The brown cones are egg-shaped, little more than an inch in length, the scales with loose edges. The wood is very durable, and it has the great recommendation of being fit for ordinary use when the tree is only forty years old. It is most valuable for those purposes where exposure to all weathers is a necessity, for it endures constant change from wet to dry. Larch-bark is used for tanning, and Venice turpentine is a product of the tree. Unlike most Conifers, it has the power of sending out new shoots when the branches have been removed close up to the stem.
Larch plantations sometimes present the appearance of death whilst they are still covered with foliage, but the leaves are yellow and twisted. This most frequently occurs in the case of trees between the ages of ten and fourteen years, and is due to the depredations of a leaf-mining caterpillar, which ultimately changes into a minute moth, the Larch-miner (Coleophora laricella). It feeds in the interior of the Larch-needles, and therefore is beyond the reach of destruction, except by felling and burning affected trees, to prevent the spread of the pest. Its ravages keep the tree in ill-health, and apparently prepare the way for the deadly attack of another small enemy, known as the Larch Canker—the fungus Peziza willkommii. Sickly trees are also liable to the attentions of a Wood-wasp (Sirex juvencus), whose appearance is usually the cause of a little terror in nervous persons. It has two pairs of smoky transparent wings, and its stout, straight, blue body terminates in a long slender point. Its large white grub spends two or three years tunnelling towards the heart of the tree and out to the bark again, but rarely attacks sound trees. It sometimes makes its appearance in a house from wood that has been used for building purposes.