Wood and Environment


The PEFC™ (Programme for the Endorsement of Forest Certification) is a procedure which verifies whether the forest has been managed according to defined standards. It aims to improve sustainable forestry management through a voluntary process of continuous improvement. Forest certification does not provide guarantees of technological qualities, but it does promise a guarantee of environmentally friendly, socially beneficial and economically viable forest management.

This certification attests to the suitability of wood for use in construction and civil engineering works. It guarantees that the natural or treated durability of the wood makes it suitable for use in the class or classes of use indicated. For a given treatment process, this certification attests to the effectiveness of the preservatives and their safety in terms of human health and environmental impact. It takes into account the requirements of Directive 98/8/EC concerning the introduction of biocide products on the market.

The FSC® (FSC C® 004568) (Forest Stewardship Council) is a label that ensures that the production of a wood-based product (e.g. furniture) has observed the required specifications to ensure good forest management.

Wood use classes

  • Class 1 : Internal building timbers - no risk of wetting
  • Class 2 : Internal building timbers - risk of wetting
  • Class 3 : External timbers used above ground contact (e.g. cladding)
  • Class 4 : External timbers used in ground or fresh water contact
  • Class 5 : External timbers used in sea water contact
Normes Bois
Normes et Classements des Bois

Classification of softwoods

Like for the hazard classes (standard EN 335-2) and for best practices in the use of wood in general, European softwoods are classified by the European standard EN 1611-1.

They are established according to a certain number of criteria and are commonly applied in France to species such as firs, spruces, pines and Douglas fir. the sawn wood is graded 0, 1, 2, 3, 4. Each grade corresponds to a certain number and maximum size of knots within a given thickness or length (details on request).

To classify northern softwoods, mainly spruce (white) and Scots pine (red), the question remains complicated. The woods are graded differently and while some will speak of grades and others of qualities, we provide a brief summary below.

Appearance graded of exported northern timber

  • Unclassified or U/S

All grades 1 to 4 (Swedish or Finnish classes, "knot-free" quality, for use in visible joinery, planed structural wood).

  • Sawfalling

Sawn timber of all grades (1-5), in proportions generally defined by sawmills and/or importers.

  • Fifths (V)

Multi-purpose grade.

  • Sixths (VI)

Lowest grade, used for packaging materials, cladding and disposable pallets. For others, the current range can be defined in 4 qualities A - B - C - D.

- quality A, grouping together grades 1 to 4, seen previously

- quality B, comparable to 5ths

- qualities C and D differentiating between 6ths.

An A/B grade will be a mixture in variable proportions of qualities A and B.

Industrial processes


This initial thermal process is fundamental prior to any transformation. It consists in lowering the moisture content of the wood by storing it in a ventilated, humidity and temperature-controlled environment, for one to three weeks. As the moisture content is now lowered to around 16%, it will significantly reduce the phenomena of warping, resin seepage and splitting on sawn boards.

Heat stabilisation

This process is environmentally friendly, using no chemical additives or petroleum products. It consists of gradually heating the wood to around 200°C, alternating re-heating and re-wetting phases. This high-temperature heat treatment is well suited to species such as pine or spruce. The process provides the wood with exceptional stability. Dimensional variations are significantly reduced with a marked reduction in warping, resin content and shrinkage. It provides a homogeneous brown colour across the grain. Heat stabilisation B (215°C) for cladding and decking boards naturally modifies the composition of the cells in the wood, significantly improving its resistance to biological degradation agents and insects. This makes it suitable for use in hazard class 3.


Consists of storing the wood in an environment below 100°C, saturated in moisture for three weeks. This process produces a homogeneous brownish colour in the grain and conserves the mechanical strength and intrinsic properties of each species.

Autoclave treatment

The vacuum pressure treatment process.
The principle of this process is to force the preservation product or solution into all the cavities of the wood. Firstly, a vacuum is applied to remove all the air from the wood, then the preservative is flooded into the vacuum chamber and forced deep into the timber by the pressure. In general, a final vacuum is applied to remove excess hydrosoluble preservative and obtain a drier surface.


Common species


An exceptional blend of quality, particularly suited to contemporary architecture. Naturally rot-proof and offers the best stability. Its natural qualities make it one of the benchmarks for exterior applications worldwide. It is regularly used for roofing and sauna construction.

Origin : Canada

Clear II quality: 95% of boards are knot-free

Naturally class 3

Clear IV quality (sawfalling) an excellent price/performance ratio


A light-coloured, fine-grained wood with small knots that are well integrated into the structure. A reference medium for colour finishes and treated wood. The 16% (+/- 2%) drying process gives it exceptional stability and quality. Available in wide-width boards.

Origin: Northern Europe.


The only conifer to lose its needles in winter. Conditioned by an exceptional climate that forces slow growth. The hard and dense wood is a benchmark for durability.

Species offering wide widths.

- Siberian Larch: due to its slow growth, it has a more homogeneous grain, a less marked veining and is slightly brighter. From legal, environmentally friendly forestry operations.

- Mountain Larch: originating from the Alps, recognized by its marked, pinkish veining. With its rustic appearance, it is more appropriate for authentic architecture.


A true benchmark for cladding, Douglas fir offers excellent value for money. Its particular feature is good resistance over time. A fast-growing species of French origin, Douglas fir has a marked, light-coloured grain and the presence of healthy, stable knots.

Origin : France

- Douglas fir: sapwood-free wood on a natural class 3 cladding.

Bois mélèze

Temparate Region Wood

Chestnut Castanea sativa

Fawn yellow or light brown heartwood with an oak-like appearance, but with a duller shade and no silver grain. Coarse texture, straight grain; heterogeneous structure. Distinct whitish sapwood, very narrow.

0.55 to 0.75.Semi-hard, semi-heavy. Total shrinkage is quite low. Moderately to slightly fibrous.

Similar to oak but slightly lower in absolute value. Generally more elastic, but less adherent and very fissile.

More suitable than oak for all machining, shaping and finishing work. Bends well. Rather difficult to dry.
Very durable heartwood, but subject to particular heat fermentation (young chestnut).

Oak Quercus pedunculata

Brownish yellow, fawn, or light fawn heartwood, darkening in the light. Quartersawn sections display prominent ray fleck. Coarse texture, generally straight grain. Heterogeneous structure. Distinct whitish sapwood

0.60 to 0.80. Medium-hard to hard.
Medium-heavy to heavy. Medium to high shrinkage. Fibrous

Excellent mechanical strength (fast growing wood). Good compressive strength, very good bending strength, fairly resilient. Adherent, not fissile in tangential direction but low radial cohesion (large rays).

Sometimes difficult to work with if the growth rings are too wide. Very delicate drying (bonding). Can be nailed, screwed or glued without difficulty. Relatively easy to finish. Very durable heartwood.

Douglas Pseudotsuga menziessi

Pinkish yellow or reddish brown heartwood, very heterogeneous and veined, resinous. Straight grain. Distinct pale sapwood.

0.50 to 0.70 (imported), 0.45 to 0.60 (reforestation) Semi-hard, medium-heavy

Medium to high shrinkage, not fibrous.

The yellow coloured wood (sides) has higher mechanical strength than the red coloured wood.
Good compression resistance.
Very good in traction and bending.
Quite fissile, poorly adherent, rather stiff, moderately resilient according to growth rate.

Easy to work with. The presence of large knots can render sawing delicate.
Fairly easy to dry (some risk of split ends and cracks).
Its immense heterogeneity presents difficulties for planing (uneven surface).

Spruce Picea excelsa

Creamy white or slightly pink wood, with a slightly resinous odour when fresh, straight grain.
Non-distinct sapwood.

0.40 to 0.50. Tender and light.
Low total shrinkage. Poorly fibrous.

Very fissile, poorly adherent (roofing products), but resilient.

Wood easy to work with. Certain tendency for fibres to pull out during sawing.

Can split when nailed, screws well.

Easy to glue, sand, and finish.
Not durable, easy to impregnate.

Maple Sycomore

White to light brown wood. Generally straight grain, but may be can also be uneven, shiny silver grain on quartersawn section.
Fine texture, lustrous sheen.
Homogeneous wood, distinct sapwood.

0.55 to 0.75. Semi-hard to hard,
medium-heavy. Medium shrinkage, moderately fibrous.

Similar mechanical properties to oak, but the sycamore offers greater resistance to splitting and shearing.

Easy to saw and plane, gives a smooth, uniform surface.
Fairly easy to dry.
Can be worked like beech. Good for turning.
Easy to glue and colour.
Not durable, easy to impregnate.

Ash Fraxinus excelsior

Pearly yellow-white wood. Straight grain, sometimes wavy.
Rather coarse texture.
Very heterogeneous structure.
Fine silver grain on quartersawn section.
In old trees, we find the black heart (olive ash).
Non-distinct sapwood.

0.65 to 0.75. Semi-hard, medium-heavy.
Total shrinkage medium to high, medium fibrous to fibrous (depending on growth rate).

Fast-growing woods (rings > 5 mm) have excellent mechanical strength.

Good compressive strength, very good tensile and flexural strength.
Elastic and very resilient.
Poorly fissile, quite adhesive.

Rather difficult to saw. Rather delicate but quite fast to saw.
Easy to machine.
Easy to glue. Takes paint, varnish or wax well.
Non-durable wood that is easily impregnated.

Beech Fagus sylvatica

White or very pale brown wood, darkening to very light reddish brown.
Fine to very fine texture.
Homogeneous structure. Straight grain.
Very apparent silver grain on the quartersawn section.
In some trees, we find a defect called red heart.
Usually non-distinct sapwood.

0.60 to 0.75. Semi-hard, medium-heavy.
High total shrinkage (especially for framework timbers).

Good axial and transverse compression strength.
Stiff in bending.
Medium to low resilience. Poorly fissile

Sometimes difficult to saw: risks of cracks and deformations during drying.
Can be worked more or less well depending on the conditions and the place of growth.
Can be turned and bent well.
The finish is always excellent.
Satisfactory adherence.

Larch Larix decidua

Brownish, reddish or purple heartwood.
Straight grain. Heterogeneous structure (clearly distinct endwood).
Narrow, yellowish white, distinct sapwood.

0.55 to 0.70. Soft to semi-hard, medium-heavy.
Medium shrinkage, often very fibrous

Good mechanical strength, especially in bending and compression.
Quite fissile, poorly adherent.
More or less impact-resistant

Technological properties similar to those of Scots pine, but more difficult and longer drying.
Nailing must be done with care.
Takes paint, stain, and varnish well.
Very durable heartwood.

Birch Purnus avium

Reddish brown clear heartwood, darkening in the light.
Generally straight grain, very fine texture.
Semi-homogeneous structure.
Distinct silver grain on quartersawn section.
Sometimes slightly veined.
Distinct sapwood with pale, yellowish or pinkish colour.

0.50 to 0.65. Semi-hard, medium-heavy.
Medium shrinkage, sometimes quite fibrous

Good strength like all fruit trees.

Saws well. Dries fairly quickly but with difficulty.
Easy to machine. Lends itself well to moulding.
bending. Glues well, takes paint, stain, and varnish well.
Moderately durable heartwood.

European walnut Juglans regia

Heartwood sometimes clearly defined, but mostly greyish with smoky-brown or blackish veins (result of alteration with production of tannin).
Often irregular grain, fine texture.
Semi-homogeneous structure. Very often naturally wavy.
Pale straw colour sapwood, not always distinct.

0.55 to 0.75 Semi-hard
Low shrinkage, poorly fibrous (most stable of native woods).

Moderately resistant to compression, mediocre under traction, quite resistant to bending.
White walnut trees are more elastic and resilient than black heart walnut trees.
Poorly fissile, moderately adherent

Machining and finishing are done with ease. However, when sawing, always take into account a fairly large waste due to the high proportion of defective wood.
Easy to dry. Walnut is mostly cut into boards.
Takes a nice polish.
Very durable heartwood.

Cembro Pine/Arolla Pinus cembra

Light yellow or reddish heartwood, darkening in the light.
Fine texture, straight grain.
Homogeneous wood, very tight growth rings.
Poorly distinct and narrow, yellowish white sapwood.

0.40 to 0.50 Light and soft wood.
Low shrinkage, low fibrous content to fibrous.

Low mechanical strength.
Not robust and not elastic.

Very easy to work with. Can be sculpted and turned well.
Can be glued, varnished and painted well.
Can be nailed and screwed well.
Dries quickly and easily.
Very durable heartwood.

Scots pine Pinus sylvestris

The pinkish, reddish or brownish red heartwood is larger than in other pines.
Generally straight grain. Very variable texture.
Low resin content, heterogeneous.
Light yellowish-white distinct sapwood, fairly broad.

0.40 to 0.50 in lowlands. 0.55 to 0.65 for mountain and northern pine.
Light to medium-heavy.
Medium total shrinkage, relatively fibrous

High mechanical strength under compression and bending.
Resilient, fairly fissile, poorly adherent.

Easy to sawing and machine, however disturbed by the presence of very hard knots and resin pockets which clog the blades and tools.
Easy and quick to dry.
Can be nailed and screwed well despite cracking.

Pearwood Pirus communis

Very homogeneous brownish-pink wood.
Very fine texture, generally straight grain, sometimes a little wavy.
Often figured on lengthways cuts.
Paler sapwood.

0.70 to 0.80. Hardwood, medium-heavy.
High total shrinkage, poorly fibrous

Good strength under bending and compression.
Slightly brittle under impact, adherent and poorly fissile.

Sawing sometimes difficult because due to its hardness.
Difficult to nail but can be screwed and glued well.
Slow but fairly easy to dry.
Can be sculpted, turned, and engraved well.
Very easy to finish.
Poorly durable wood.

Lime Tilia spp.

White to pale yellow wood, turning slightly pink or reddish in light.

0.45 to 0.55. Soft and light wood.
Medium shrinkage, poorly fibrous.

Average strength in relation to its weight; slightly brittle under impact, moderately adherent and fissile.

Can be worked very easily. Easy and fast to dry, excellent for turning and carving.
No difficulty in gluing or finishing unless there are waxy materials in the wood.
Non-durable wood, but easily impregnated.

Western Red Cedar Thuya plicata

Hardwood and very variable colour, ranging from pale yellow to brownish-red.

Strong peppery odour, persistent.
Distinct growth rings, usually very tight. Straight grain.

Pale, very narrow sapwood.

0.30 to 0.35. Very tender and light.
Low shrinkage but quite fibrous

Low mechanical strength.
Fissile and brittle under impact.

Easy to work with. Drying fairly difficult and slow.
Nails and screws do not hold well and must be protected against corrosion (very acidic wood).

Gluing and finishing are not a problem.
Very durable heartwood.

Tropical Region Woods

Ipe or Brazilian walnut

Black (black ebony) or dark brown heartwood with black veins (veined ebony), Makassar type).

Very fine texture, very homogeneous.
Distinct whitish or greyish sapwood, broad, 5-10 cm, not usable and usually removed after felling.

0.95 to 1.25. Very hard and heavy wood.
Low shrinkage.
Very stable.

Fairly good mechanical strength, especially under bending and compression, rather brittle, average impact resistance, fissile.

Difficult to work with due to hardness and abrasiveness, requiring appropriate tools and machines.

Requires delicate, very slow drying process.

Tendency to split when screwing (starter holes required).

Frake Combretaceae

Creamy white heartwood that darkens slightly in the light, reminiscent of light oak.

Medium texture. Generally straight grain.
Indistinct sapwood.

Soft to semi-hard.

A soft, light wood with fairly good mechanical properties.

Easy and very fast drying. Works very well but difficult to finish due to linting after sanding.

Relatively abrasive.
Easy to glue, nail, screw, varnish.
Poorly durable heartwood.


Straw yellow or light brown wood.
Medium to coarse texture.
Rare, slightly marked and irregular counter-grain.
Barely differentiated sapwood.

0.45 to 0.65. Soft to semi-hard, light.
Low shrinkage, poorly fibrous

Good mechanical strength, rather fissile.

Medium impact resistance.

Very easy to work. Easy and quick to dry.
Nailing, screwing, gluing, finish without any problems.
Moderately durable heartwood.

Iroko Moraceae

Yellowish brown heartwood, darkening to a more or less deep brown in the light.

Medium to coarse texture, more or less regular grain giving a ribboned appearance when quartersawn.
Distinct pale yellow sapwood, 5 to 6 cm.

0.60 to 0.75. Semi-hard and medium-heavy.

Rather low total shrinkage, moderately fibrous.

Good mechanical strength.
Medium impact resistance, comparable to oak.

Generally easy to machine. Dries quickly and easily.
No problem for nailing, screwing,

and glueing. Delicate finish with certain types of products.
Very durable heartwood.

Kapur Dipterocarpaceae

Reddish brown heartwood. Sometimes straight grain but most often irregular.

Coarse texture. Lines of resinous canals with white content; camphor odour when fresh.

Distinct, yellow or pink sapwood, fairly narrow (6 cm).

0.60 to 0.80. Semi-hard, medium-heavy.
Fairly high shrinkage, moderately fibrous

Good mechanical strength.
Quite resilient. Poorly fissile

Quite easy to work with despite tools sometimes being blunted quickly.

Fairly easy to dry.
Takes glue, nails, and screws satisfactorily.
Problem-free finishing.
Very durable heartwood.

Dark red Meranti

Pinkish brown to red heartwood, even dark reddish brown.

Rather coarse texture. Frequent counter-grain.
Whitish resinous streaks or veins on lengthways cuts.

Distinct pale grey-brown sapwood, 2 to 5 cm wide.

Variable: 0.55 to 0.70.
Semi-hard and medium-heavy. Medium shrinkage.
Moderately fibrous.

Good mechanical strength

Machining is not difficult but some species are quite abrasive.

Dries quickly and easily.
Nailing, screwing, gluing and finishing are not particularly difficult.

Moderately durable heartwood.

Niangon Terrieta utilis

Pinkish brown reddish brown mahogany heartwood.
Often tangled grain, irregular counter-grain.

Very apparent silver grain on the quarter-sawn section.
Oily to the touch (resinous substances).
Rather coarse texture.
Distinct greyish sapwood, narrow to fairly broad.

0.60 to 0.80. Semi-hard and medium-heavy.
Medium total shrinkage, moderately fibrous

Good mechanical strength, quite elastic and impact resistant.

Easy to machine but sometimes clogs the tools.
Dries quickly and easily.
Problem-free nailing and screwing.
Gluing and finishing are sometimes difficult if the wood is very greasy (degreasing necessary).
Durable heartwood.

Sapelli Meliaceae

Mahogany-coloured heartwood, reddish brown with golden highlights.
Straight grain, counter-grain giving a very regular ribboned aspect but also sometimes moiré or wavy.

Fairly fine texture. Quite persistent, characteristic smell of cedar.

Pink-grey sapwood.

0.60 to 0.75 Semi-hard
Low total shrinkage, moderately fibrous.

Good compressive and flexural strength but slightly stiff and brittle under impact.

Quite fissile.

Easy to machine if the counter grain is not too heavy.
Drying must be done slowly.
Nailing, screwing, gluing and finishing are not particularly difficult.

Moderately durable heartwood.

Sipo Meliaceae

The heartwood is brown-pink mahogany with purplish highlights.
Usually irregular grain, counter grain

medium, ribboned on the quarter-sawn section.
Medium texture. Very homogeneous texture.
Distinct greyish-pink sapwood, 2 to 4 cm long.

0.55 to 0.65. Fairly tender, light to medium-heavy.
Total shrinkage quite low, poorly fibrous.

Good mechanical strength under compression and bending, fairly brittle on impact.

No particular machining difficulty.
Fairly easy to dry.
Nailing, screwing, gluing and finishing without difficulty.
Moderately durable to durable heartwood

Tatajuba Moraceae

Yellow heartwood turning dark brown in the light, frequent but light countergrain, medium to coarse texture, fine, inconspicuous silver grain.

Distinct creamy white sapwood

Medium-heavy to heavy. Low total shrinkage

Good mechanical strength under compression and bending, fairly resistant to impact

Machining without difficulty or difficulties due to the counter grain.
Drying without significant risks.
Good finishing and gluing; pre-drilled holes sometimes necessary for screwing.

Durable heartwood

Teak Tectona granis

Greenish-brown heartwood when fresh, darkening to a warmer, copper-tinged colour when exposed to light.

Generally straight grain.
Rather coarse texture, heterogeneous structure.
Oily wood, due to the presence of resins.

Distinct, whitish sapwood.

0.55 to 0.80. Semi-hard and medium-heavy.
Very low total shrinkage, very poorly fibrous

Medium mechanical strength; rather elastic, moderately resistant to impact.

Moderately fissile, poor resistance to wear.

Fairly easy to machine, sometimes blunting.
Dries easily and fairly quickly, without cracks or deformations.

Nails and screws well with some risk of splitting.
Gluing and finishing are quite delicate (greasy wood).

Is usually oiled and not varnished.