French Softwood Species Species ● Uses ● Grading system
Timber fROM sustainable managed forestS Promoting French Lumber and Wood Products www.FrenchTimber.com
Summary FrenchTimber presentation
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Why buy French products? . . . . . . . . . . . . . . . . . . . . .p.3 French forests, sustainable management . . . . . . . . . . .p.3 Fir - Spruce
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Douglas Fir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .p.6-7 Scots Pine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .p.8-9 Maritime Pine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .p.10-11 Appearance grading rules
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Structural grading rules . . . . . . . . . . . . . . . . . . . . . . .p.14-15
FrenchTimber : Promotion of French timber species and wood products The French wood industry is a leading player in European timber production. It has been managing its diversified forests for centuries, both ecologically and economically . France’s forests are in constant expansion.
A huge variety of species in both hardwood and softwood has contributed to the exceptional worldwide reputation of French timber and wood products.
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The FrenchTimber association was founded in 2001 at the initiative of the "Fédération Nationale du Bois". Strongly supported by the related timber industries throught France Bois Forêts, FrenchTimber is dedicated to: ● Promote the use of the sustainably produced timber and wood products on an international and national level. ● Facilitate the supply of timber to foreign companies by promoting the huge expertise and personalised service offered by the French timber industry.
The FrenchTimber association has been created as a tool to ease the supply of quality timber. ● FrenchTimber distributes technical and economical information to international purchasers (importers, wholesalers, manufacturers and decision makers). ● The French timber industry offers quality, expertise and the ability to adapt their production to specific demands. ● The French timber industry exercises the PEFC program of sustainable forest management, as a proof of its commitment to the future.
Why buy French products ?
Standing wood volume (millions of cubic meters)
Advantages of French softwood sawn timber : ● Big dimension timber, ● Available in long lengths (up to 12 meters), ● A huge range of products ● Sustainably managed forests.
French sawmills can offer you : ● Standard dimensions using the european grating system, ● Dimensioned according to customer’s specifications, ● Dried, planed, finger-jointed edge glued , treated products... ● Expertise together with continually developed technology, ● Sales teams traditionally dedicated to international trade.
Resources French forests increase their standing wood volume by 88 million m3 every year. Fifty percent of this volume is harvested annually. The forest contains 128 different species (30 of which are commonly sawn). The total wood volume represents 2 billion m3
Breakdown of the French harvested area
Hardwood
61% 39%
Softwood
An overview of sustainable forest management In 1827, France has set up a controlled forest management system. Drawing from experience, France has initiated the PEFC certification scheme (Program for Endorsement of Forest Certification Schemes) which guarantees resource renewal. During the last 50 years French forests have increased by 35% while at the same time maintaining their biological diversity. PEFC guarantees the origin of the products offered.
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Annual sawn timber production :
Fir - Spruce Abies Alba - Picea Excelsa
3.900.000 m3
ONF - J.P. Chasseau
These are tall trees (up to 30 meters) with a large diameter (1 meter), growing in mountainous areas (over 800 meters high). Their trunks are straight and cylindrical, showing a smooth bark. They account for 1.383.000 ha within the whole French forest.
Spruce
Fir
Workability Preservation Wood characteristics • Fir Heartwood is not distinct from sapwood. Sawn timber is glossy creamwhite. Fir is straight-grained, with thin and regular texture.
Fir and spruce can be used in class 1 without treatment (dry surrounding conditions) and in class 3 (humid atmosphere) after treatment. Timber impregnation can be made in class 2 (dipping) or class 3 (vacuum pressure treatment)
• Spruce Heartwood is not distinct from sapwood. Sawn timber is white to pale pink coloured. Spruce is straight-grained with thin and regular texture.
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Mechanical characteristics Figures given at 12 % moisture content (straight-grain timber and free from defects) Average density
450 kg/m3
Total average volumetric shrinkage
11,4%-12,7%
Brinell hardness perpendicular to the fibres
14 N/mm2
Modulus of rupture under bending
100 MPa
Breaking stress under axial compression
44 MPa
Modulus of longitudinal elasticity under bending
12 700 MPa
Copyright B.RĂŠrat
CNDB
Main uses Fir and Spruce are ideal for framework, including glued laminated timber, as well as for wooden structures (for instance : footbridges). Sawn timber is also currently used for joinery, flooring, skirting boards and mouldings.
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Annual sawn timber production :
Douglas Fir Pseudotsuga Menziesii
810.000 m3 Originally from North America, Douglas-Fir has been introduced in France in 1842. Wide-spread today, its production keeps growing (+15% a year). Its rapid growth gives birth to tall trees (50 meters), with a large diameter (2 meters), straight-grained, thick and cracked bark.
Wood characteristics
ONF - J.P. Chasseau
Its reddish-brown heartwood is distinctive from its cream white sapwood. Douglas-Fir is straightgrained, with medium texture and sound knots.
Preservation Douglas-Fir is naturally durable: heartwood is resistant to mushrooms. Douglas-Fir can be used in class 3 (timber exposed to weathering). Impregnation must be done by vacuum pressure treatment.
Workability
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Mechanical characteristics Figures given at 12 % moisture content (straight-grain timber and free from defects) Average density
540 kg/m3
Total average volumetric shrinkage
10,6%
Brinell hardness perpendicular to the fibres
18 N/mm2
Modulus of rupture under bending
83 MPa
Breaking stress under axial compression
47 MPa
Modulus of longitudinal elasticity under bending
12 100 MPa
Main uses Thanks to its availability in long lengths, Douglas-Fir is widespread in the building industry. Ideal for framework, including glued laminated timber (Douglas-Fir, once dried, becomes very hard), as well as for cladding, exterior joinery and layout. It can also be used in exterior structure such as decking, footbridges and floating docks.
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Scots Pine
Annual sawn timber production : 3
700.000 m
Pinus Sylvestris
Widespread species in France, it is found in the northern part of the country, standing on 1.130.000 ha. Due to its good resistance to cold weather, scots pine is often seen in the French mountainous areas. This species, which grows slowly, features a tall and straight trunk.
Wood characteristics Scots pine shows a distinct yellowish white sapwood and a pinkish to reddish-brown heartwood. Generally straight-grained with fine texture.
Preservation Scots pine’s heartwood is naturally resistant against mushrooms but is difficult to impregnate. Sapwood is easily impregnate. Sawn timber is usable in both class 4 and 5 after vacuum pressure treatment.
Mechanical characteristics Figures given at 12 % moisture content (straight-grain timber and free from defects)
Workability
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Average density
550 kg/m3
Total average volumetric shrinkage
14,1%
Brinell hardness perpendicular to the fibres
18 N/mm2
Modulus of rupture under bending
109 MPa
Breaking stress under axial compression
56 MPa
Modulus of longitudinal elasticity under bending
14 500 MPa
Main uses
Copyright B.RĂŠrat
Scots pine is commonly used for interior (moulding, skirting boards, panelling and flooring ‌) and exterior joinery as well as framework. Scots pine is also appreciated for furniture and exterior fittings (acoustic screens, handrails, cladding, decking and footbridges).
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Maritime Pine
Annual sawn timber production :
Pinus Pinaster 3
2.140.000 m
Maritime pine represents more than 10% of the total French forest, it covers about 1.360.000 ha. These are tall trees, with brownishred cracked bark.
Workability Preservation Sapwood is not naturally durable, though easily impregnable by treatment (either by impregnation or by vacuum pressure). Heartwood is naturally durable . After vacuum pressure treatment, it can be graded in both classes 4 and 5.
Mechanical characteristics Figures given at 12 % moisture content (straight-grain timber and free from defects)
Wood characteristics Maritime pine shows a distinct yellowish white sapwood and a reddish heartwood. It is mainly straight-grained with medium texture.
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Average density
560 kg/m3
Total average volumetric shrinkage
11,9%
Brinell hardness perpendicular to the fibres
20 N/mm2
Modulus of rupture under bending
90 MPa
Breaking stress under axial compression
47 MPa
Modulus of longitudinal elasticity under bending
10 200 MPa
Main uses
ARKEA CrĂŠation
The main uses for maritime pine sawn timber are joinery, both interior (mouldings, skirting boards, flooring and panelling) and exterior, as well as furniture and framework. It is also commonly used, when treated, for exterior fittings (cladding, outdoor urban furniture). Finally, this species is widely used for packaging, crates and pallets production.
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Visual appearance grading of softwood According to standard NF EN 1611-1(available upon request)
Grade 0 Main uses: layout, joinery, furniture, moulding, furniture.
Fir - Spruce
Douglas Fir
Size of knots
10% width + 10mm
Allowed knots
Loose (sound, dead)
Knots per worst meter on face
2
Knots per worst meter on edges
1
Encased bark
Not permitted
Resin wood
Not permitted
Rot
Not allowed
Stain
Not permitted
Insect attacks
None
Wane
3mm (20% length)
Pith
None
Splits
Not permitted
Size of knots
10% width + 20mm
Allowed knots
Sound, dead, intergrown bark
Maritime Pine - Scots Pine
Grade 1 Main uses: layout, structural timber, beams, trusses, industrial framework, planed timber, furniture.
Fir - Spruce
Douglas Fir
Maritime Pine - Scots Pine
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Knots per worst meter on face
4
Knots per worst meter on edges
2
Encased bark
2 (100 mm maxi.)
Resin wood
Not permitted
Rot
Not allowed
Stain
Not permitted
Insect attacks
Not permitted
Wane
5 mm (20% length)
Pith
Allowed
Splits
Not permitted
Visual appearance grading of softwood According to standard NF EN 1611-1(available upon request)
Grade 2 Main uses : layout, structural timber, traditional framework, beams, glued laminated timber, planed timber.
Fir - Spruce
Size of knots
10% width + 35mm
Allowed knots
Sound, dead, intergrown bark, rotten
Knots per worst meter on face
6
Knots per worst meter on edges
4
Encased bark
2 (200 mm maxi.)
Resin wood
30% of the board
Rot
Not allowed
Stain
Allowed (10% of the board)
Insect attacks
Not permitted
Wane
10 mm (30% length)
Pith
Allowed
Splits
Not permitted
Size of knots
10% width + 50mm
Allowed knots
All
Knots per worst meter on face
unlimited
Knots per worst meter on edges
unlimited
Encased bark
4 (300 mm maxi.)
Resin wood
50% of the surface
Rot
Not allowed
Stain
50% of the surface
Insect attacks
Black pinholes : 15% of the surface
Wane
20 mm (50% length)
Pith
Allowed
Splits
20% of the length
Douglas Fir
Maritime Pine - Scots Pine
Main uses: packaging, crates and pallets.
Fir - Spruce
Douglas Fir
Maritime Pine - Scots Pine
Photos : CTBA
Grade 3
Grade 4 Main use : formwork. Grade 4 is not shown here with photographs. It includes all sawn timber that could not be classified in higher grades.
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Two systems for structural grading of softwood sawn timber The use of timber in structural applications is linked to the knowledge of its mechanical characteristics. The aim of structural grading is to sort timber into different grades depending on its forecasted mechanical performance. Two grading systems achieve : ● Visual Grading (according to standard NFB 52-001, 12.98). This system defines grades of timber using criteria based on visual appearance, sawing method, biological degrade and defect. Three visual classes result of this method: ST-I, ST-II or ST-III. Graded timber can then be allocated to a CEN Strength Class. ● Machine Grading (according to standard EN 519, 03.98). This system allows timber to be graded to a CEN Strength Class (C 30, C 24 and C 18) by measuring mechanical characteristics.
Relationship between mechanical and visual classes Strenght Class
Visual Class
Possible end uses for framework
C 30
ST-I
Glued laminated timber
C 24
ST-II
Trusses and glued laminated timber
C 18
ST-III
Traditional framework : Post and Beam
Distribution of species by strength class The main softwood species in France were classified in the three strength classes after being studied according to visual grading criteria. (See table)
Species
ST-I
ST-II
ST-III
Firs & Spruces Douglas fir Pines
(1)
(1) Scots pine, Maritime pine, Austrian pine, Corsican pine
Marking timber graded by mechanical resistance For use in the European market, each piece of graded structural timber must be marked according to standard NF B 52-001. This includes: visual class (ST-…) or strength class (C …), the specie, the producer and the reference standard used to grade (NF B 52-001, EN 519).
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Visual grading of structural softwood The table below indicates measurements and criteria to be considered when grading. (Methods of measurement are described in the rule NF EN 1310) (Complete standard NF B52-001 available upon request).
Criteria Firs - Spruces - Pines Width of annual rings (mm) Douglas Fir Dimensions of knots Firs - Spruces - Douglas fir on one face Pines Dimensions of knots Firs - Spruces - Douglas fir on one edge Pines
ST-I ST-II ST-III ≤ 6 mm ≤ 8 mm ≤ 10 mm ≤ 8 mm ≤ 10 mm ≤ 12 mm Ø ≤ 1/6 l Ø ≤ 1/2 l Ø ≤ 3/4 l Ø ≤ 1/10 l Ø ≤ 1/3 l Ø ≤ 2/3 l Ø ≤ 2/3 of the thickness and Ø ≤ 40 mm Ø ≤ 1/3 e Ø ≤ 1/2 e Ø ≤ 2/3 e
Traversing shakes
Max length < 2 widths of the piece
L < 600 mm
Not traversing shakes
Max length < half widths of the piece
unlimited
Big resin pockets
Not permitted
Bark pockets Slope of grain (expressed as a ratio)
Allowed if < 80 mm
Not permitted local
1/10
1/4
general
1/14
1/6
length
Not permitted
< 1/3 length of the piece and < 100 cm
width
Not permitted
< 1/3 of the thickness of the edge
Wanes Blues stain mistletoe traces
Permitted
Black holes
Permitted only on one face
Dote
Not permitted
Mechanical characteristics of strength classes (NF EN 338)
Criteria
C 30
C 24
C 18
Bending
13,2
10,5
8,0
Parallel compression
11,0
9,0
8,0
Parallel tension
8,0
6,0
5,0
Longitudinal shear
1,3
1,1
0,8
Perpendicular compression
2,5
2,3
2,0
Perpendicular tension
0,15
0,15
0,15
Conventional deformation modulus : Shear
750
690
550
Conventional deformation modulus : Longitudinal, shear force included
12.000
11.000
10.000
All values are given in MPa (1MPa = 10kg/cm2) for a timber moisture content of 12%.
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Lille Fécamp Le Havre Rouen Caen
St-Malo
PARIS
Nancy
Strasbourg Mulhouse
Nantes
Nantes
La Rochelle
Lyon
Rochefort Bordeaux
Bordeaux
Marseille Sète
Fos-sur-Mer
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