Larch

European larch
Larix decidua

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European larch belongs to the scientific genus Larix and is a member of the pine family (Pinaceae).

European larch (Larix decidua) is a deciduous conifer growing to over 40m and flowering March to April.

Lifespan: In the UK the oldest known specimens are over 250 years old.

Characteristics

Bark is greyish brown, thick and fibrous with vertical fissures. Old trees develop deep, broad, scaly ridges. Branches are down swept with ascending ends. Lower branches are heavy and dropping. Shoots are light grey-yellow, grooved, hairless and bear woody knobs (short round shoots) from which the needles grow in tufts.

Foliage is pendulous. Needles are 2–3cm, bright emerald green when first open, becoming darker; they protrude in circular clusters or tufts from woody knobs on the twigs. Needles near twig tips are always set singly. Larch needles are softer in texture to other conifers and fade to orange and yellow in autumn before falling.

European larch is monoecious: both male and female flowers are found on the same tree. Male flowers on underside of shoots are 5mm globular clusters of creamy yellow anthers. Female flowers at the tips of shoots are typically 8mm. They are attractive, flower-like clusters of scales in rosy pink, green or white, aptly named ‘larch roses’. The tree is wind pollinated.

The female flowers ripen over six months into brown, barrel shaped cones 3–4cm with a hollow top which slowly expand their rounded scales over time to release winged seeds. Many trees retain dead cones for several years.

Larch tree

Larch cones

Larch flowers

Distribution

The European larch is native to the mountainous regions of the Alps, Sudetes and the Carpathians in central Europe. It was introduced to the UK in the 17th century and widely planted as a timber tree and, because of its attractive autumn foliage, for ornamental purposes.

European larch, Japanese and Hybrid larch together make up 8% of the total conifer area of the UK.

The first UK larches were planted by Dunkeld Cathedral in Scotland in 1738 by the second Duke of Atholl; one of these parent larches is still standing.

Human value

Larch timber has a pale creamy-brown sapwood and a red-brown heartwood. It is a very resinous wood, straight grained and fine textured. The heartwood is naturally durable and the sapwood can be treated with preservative.

Larch timber is hard and tough (some 50% harder than Scots pine). Because of this, and its natural durability it is used for external joinery such as fencing, gates and estate repair work. It is also used in structural joinery such as roofing and beam work and for cladding and flooring and furniture-making.

Larch in autumn
Larch flower

Wildlife value

Larches make very attractive forests; their feathery foliage and more open canopy make conditions much lighter on the woodland floor than other conifer forests. In the UK this provides ideal conditions for bluebells, wood sorrel, creeping soft grass and important wildlife shrubs like bramble.

The shrub layer in larch forests provide food and cover for woodland birds. Sparrow hawks and goshawks nest in the canopy, while smaller birds like chaffinch, siskin, redpoll, crested tit and the crossbill, along with red squirrels, feed on the cone seeds. Larch buds are enjoyed by the black grouse.

The European larch supports a number of moth species including the case bearer moth, the larch tortrix, the larch pug and numerous other micro-moth species. The shrub layer within the forest also supports woodland butterflies such as the green hairstreak.

Larch forests are warm and moist and often abundant in fungi. Some fungi are only found in association with larch such as the larch bolete and the rarer larch knight.

Management

European larch is a light-demanding, often pioneer species with rapid early growth. It is one of the fastest growing of all trees and requires ample light and space to grow well, and soils which are of moderate fertility and freely draining. The tree roots deeply, so it does not tolerate shallow soils or very dry, waterlogged, compacted or nutrient poor soils.

It is wind-firm but suffers from exposure and, because it flushes early, can be very susceptible to damage by spring frosts. It only casts a light shade, so it can be used as a nurse for both broadleaves and conifers.

Seed can be sown mid- to late March and does not require any pretreatment unless it has become dormant. Most European larch trees in the UK are grown from seed sourced from high alpine regions and can be more susceptible to canker. Seed collected from registered UK stands or provenances from the Czech republic (Sudetes region) and Slovakia are preferred, as these are known to do well in the UK and are less vulnerable to canker.

Larch canker (Lachnellula willkommii) is one of the most harmful diseases of larch. It is a fungal disease which may be associated with frost damage.

European larch can also be affected by Heterobasidion (Fomes root and butt rot), another butt rot fungus, Phaeolus schweinitzii, and the needle cast fungus Meria laricis.

Very recently, larch has been found to be susceptible to the introduced pathogen, Phytophthora ramorum, which is causing widespread mortality to Japanese larch in western parts of Britain and continues to spread.

Susceptibility of European larch to P. ramorum is uncertain at present. Visit Forest Research for the latest information.

In northern parts of the UK larch species have been killed following attacks by the larch bark beetle (Ips cembrae).

Larch trees

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Photographs © Forestry Commission