Larches are conifers in the genus Larix, in the family Pinaceae. Growing from 20
to 45 m tall, they are native to much of the cooler temperate northern
hemisphere, on lowlands in the north and high on mountains further south. Larches
are among the dominant plants in the immense boreal forests of Russia,
Canada, and Scandinavia. Although a conifer, the larch is a
deciduous tree and loses its leaves in the autumn. 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. 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 with short bracts, with
more southerly species tending to have longer cones, often with exserted
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, 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. = Eurasian =
Northern, short-bracted Larix decidua 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 Dahurian Larch. Plains of
central and eastern Siberia. Larix kaempferi Japanese Larch.
Mountains of central Japan. Larix principis-rupprechtii Prince
Rupprecht's Larch. Mountains of northern China.
Olgan Larch or Olga Bay Larch is sometimes treated as a distinct species
Larix olgensis. Southern, long-bracted
Larix potaninii Chinese Larch. Mountains of southwestern China.
Larix himalaica Langtang Larch.* Mountains of central Himalayas.
Larix mastersiana Masters' Larch. Mountains of western China.
Larix speciosa Yunnan Larch.* Mountains of southwest China, northeast Burma.
Larix griffithii Himalayan Larch. Mountains of eastern Himalaya
= North American = 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, 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 that feed on larches.
Diseases Larches are prone to the fungal canker
disease Lachnellula willkommii; 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.
Uses 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..
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. References
= Notes = = Bibliography =
Gernandt, D. S. & Liston, A.. "Internal transcribed spacer region evolution in
Larix and Pseudotsuga". American Journal of Botany 86: 711–723.
doi:10.2307/2656581. JSTOR 2656581. Gros-Louis, M.-C., Bousquet, J., Pâques,
L. E., & Isabel, N.. Species-diagnostic markers in Larix spp. based on RAPDs and
nuclear, cpDNA, and mtDNA gene sequences, and their phylogenetic
implications. Tree Genetics & Genomes 1: 50–63. Abstract.
Rushforth, Keith [1980]. Bäume [Pocket Guide to Trees]. Bern: Hallwag AG. ISBN
3-444-70130-6. Semerikov, V. L., & Lascoux, M.. Genetic
relationship among Eurasian and American Larix species based on allozymes.
Heredity 83: 62–70. Wei, X.-X., & Wang, X.-Q.. "Phylogenetic
split of Larix: evidence from paternally inherited cpDNA trnT-trnF region". Plant
Systematics and Evolution 239: 67–77. doi:10.1007/s00606-002-0264-3.
Wei, X.-X., & Wang, X.-Q.. "Recolonization and radiation in Larix:
evidence from nuclear ribosomal DNA paralogues". Molecular Ecology 13:
3115–3123. doi:10.1111/j.1365-294X.2004.02299.x.
PMID 15367124. Further reading
Earle, Christopher J., ed.. "Larix description". The Gymnosperm Database.
Givnish, Thomas J.. "Adaptive significance of evergreen vs. deciduous
leaves: solving the triple paradox". Silva Fennica 36: 703–743. The larch
paradox—Finally, let us turn to one last, enduring ecological paradox: the
deciduous habit of larches at high latitudes in nutrient-poor peatlands in
the northern hemisphere, where evergreen plants are expected to dominate and
often do. Quote from p. 729. Phillips, D. H., & Burdekin, D. A..
Diseases of Forest and Ornamental Trees. Macmillan ISBN 0-333-49493-8.
External links Eichhorn, Markus. "The Larch". Test
Tube. Brady Haran for the University of Nottingham.