Larch

Common larch

Larch (Larix decidua)

Origin: Europe

Nomenclature:

• Polish: modrzew europejski, modrzew
• English: European larch, common larch, larch
• French: meleze d'Europe, meleze
• German: Larche, Europaische Larche, Gemeine Larche
• names used in other countries: in Austria - lergat, in the Netherlands - lariks, in Sweden - lark, in Turkey - kara cam, in Italy - larice.

Larch lumber, Availability
38 mm – KD – unedged – I / III grade
52 mm – KD – unedged – I / III grade

Occurrence:

Larch was originally only found in the Alps, the eastern Sudetes, the Tatra Mountains and the Polish lowlands. Nowadays, thanks to forest cultivation, it is widespread throughout Europe. It has low nutrient requirements, so it grows well in many habitats.  

Tree habit:

European larch (Larix decidua Mill.) is a coniferous tree with needles that fall in winter. This tree reaches a height of up to 40 m and a diameter of up to 1.2 m. It has a fairly slender and conical crown, which often develops into a broad crown with a flattened top. Branches grow irregularly at right angles to the trunk axis. Trees growing in the forest and in closed clusters are straight, cylindrical to 2/3 height, arrows without branches. Trees growing alone are prone to curvature (sable shape). The bark is smooth in youth, with a shade of grey ash, becoming scaly and deeply cracked with age.

Structure type:

Coniferous (no vessels).

Sapwood:

Narrow, 1-3 cm wide, yellowish, clearly delimited from heartwood.

Heartwood:

Reddish brown when fresh.  

Fragrance:

Freshly sawn wood has a distinct resinous smell, which gradually fades over time.

Pattern:

The grain is very clear due to the difference in density and colour between earlywood and latewood. The earlywood is lighter in colour and its transition to latewood is quite sharp. Core rays are only visible on the radial cross-section and very faintly at that. The wood lacks stratified construction. Small resin leaks in the form of glassy spots or streaks are visible on all sections of the wood. Mostly straight-fibre structure, even construction.

Typical defects:

Striped fibre twist, convergence, curvature, fibre twist, resin blisters, excessive resin content.

Physical properties of larch wood:

According to the six-grade density scale, European larch is a moderately light wood (Class IV). The average density for the air-dry state is 590 kg/m³. The moisture content of the fibre saturation point is 30%. Larch is a moderately shrinkable wood, with a shrinkage anisotropy of 2.3.

Mechanical properties of Larch wood:

Straight-grained larch wood has strength properties. For example, the average flexural strength is 95 MPa and the compressive strength along the fibres averages 55 MPa. The average hardness of the tested wood, determined by the Janka method on the cross-section, is 38 MPa, and the average modulus of elasticity along the fibres, determined in tangential bending, is approximately 13.8 GPa. The strength of larch wood is determined by the width of the annual increments; in larch wood its density and strength parameters, including hardness decrease.

Hardness:

European larch is a wood with medium resistance to fungi. The natural durability of larch heartwood against fungi (on a 5-grade scale) is between 3 and 4. At the same time, it is a type of wood that is very difficult to impregnate with wood preservatives. 

Drying:

It dries relatively quickly, but with a tendency to develop cracks and deformations.

Working:

Larch lumber is relatively difficult to process by hand and machine (especially fresh). The liquid resin will bond the cutting tools, significantly increase frictional forces and accelerate wear.

Sanding:

The wood sands and polishes well.

Joining:

gives strong connections with metal fasteners (nails, screws, bolts), but pre-drilling of the wood is required. The species is not very sticky. Polyurethane-epoxy, single and two-component polyurethane and hybrid adhesives should be used for bonding.

Finishing:

It has low compatibility with stain, making it necessary to condition the surface before staining or applying certain varnishes, as there is a possibility of damage with surfaces finished with polyester varnishes.

Intended use:

Recommended use for parquets: larch wood, due to its relatively low density and the associated reduced hardness, is mainly used in the form of floor boards (less frequently in laminated elements) in rooms with less traffic. These boards, once laid, are usually covered with sealed varnish coatings. With their expressive pattern and intense red-brown colour, they give the room a special character. Larch was much more commonly used in flooring in previous centuries and is therefore now often needed for restoration work or the renovation of old parquet or coffered floors.
Other uses – larch wood has many uses. In the past, it was used to make barrels, vats and even piping, as well as machine parts and shingles. Today, it is used for the production of wood plastics, as well as the manufacture of joinery and furniture. Larch is used for building facades and decking.

Similar species:

Similar species in terms of visual appearance and characteristics are other larch species, such as: Larix dahurica Turcz, Larix laricina K. Koch, Larix kaempfei Carr, Larix occidentalis Nutt.

Siberian larch (Larixsibirica Ledeb.) from Asia
The wood of the Siberian larch is a narrow-skinned wood with poorly coloured heartwood. It is noticeably lighter in colour than domestic European larch wood. The wood pattern consists of well-defined annual increments as well as knots and small resin seeps. In terms of physical and mechanical properties, Siberian larch wood is almost identical to or slightly superior to European larch. It is a medium shrinkage wood with medium shrinkage anisotropy. The wood also has a medium natural durability. In addition to floorboards, Siberian larch is primarily used for decking and building facades.

Notes:

The presence of resin makes working difficult.

Trivia:

Larch was once believed to be a tree in which the souls of the dead were trapped, but was more often seen as a symbol of renewal, youth and the beauty of life. The reddish-yellowish wood of the larch, which is extremely hard and resinous, and has been known for centuries for its durability, was readily used for the construction of houses and, in particular, religious buildings. They also used larch resin itself (the so-called "Venetian resin") to make paints, which were used by, among others, Rubens and Rembrandt. Larch boards were also used as a background for paintings: Renaissance artist Rafael Santi, for example, used them for his works.