CentreforWoodScienceandTechnology( Timber … gil-moreno timber... · Authors: David Gil-Moreno, Dan Ridley-Ellis & Paul McLean Timber properties of

Ins$tute for Sustainable Construc$on

Centre for Wood Science and Technology

[email protected] http://blogs.napier.ac.uk/cwst http://www.forestry.gov.uk/forestresearch

Authors: David Gil-Moreno, Dan Ridley-Ellis & Paul McLean

Timber properties of Noble fir, Norway spruce,

western red cedar and western hemlock

grown in Great Britain



The world we are in



Aims !  What species can be a complement to the forest industry?

"  Norway spruce; Noble fir; Western hemlock; Western red cedar

!  Mechanical properties: how well do these species perform in G.B.? Can I use them as structural timber material? "  How do I classify? EN338



Structural timber. Strength classes EN 338:2009

Wood property Characteristic property values

(softwoods)

C14 C16 C18 C20 C22 C24

Strength (N mm−2) 14 16 18 20 22 24

Stiffness (kN mm−2) 7 8 9 9.5 10 11

Density (kg m−3) 290 310 320 330 340 350



Even-aged plantations, 3 sites per species

•  Scotland: •  1: Norway spruce and red cedar •  2: Noble fir and western hemlock

•  Wales: •  3: Norway spruce, red cedar, Noble

fir •  4: Western hemlock

•  England: •  5: All the species

Material and Methods

1

5

3

4

5










Centre for Wood Science and Technology Material and Methods

! 3 plots for every species in each site (Scotland, Wales and England ) ! Diameter, Height, Straightness, and acoustic testing

! 9 trees per site and species ! Taper, ! Collection of specimens: discs, logs for

production of clears and structural-size timber. ! Branches in Scottish tree samples

! Processing of samples ! Battens: pith to bark, north to south ! Clears: pith to bark ! Discs


Centre for Wood Science and Technology Material and Methods !  Processing into battens; drying;

Cambial age = 45


Centre for Wood Science and Technology Material and Methods !  Destructive four point bending, EN408:2010



Sitka1

Pieces 955

Age of Samples (Years) Unknown

E0,mean (kN mm−2) 8.30 C16

Density (kg m−3) 387

ρk (kg m−3) 330 C20

MOR (N mm−2) 32.7

fm,k (N mm−2) 19.6 C18

Strength class C16

Wood property Characteristic property values

C14 C16 C18 C20 C22 C24

fm,k (N mm−2) 14 16 18 20 22 24

E0,mean (kN mm−2) 7 8 9 9.5 10 11

Density (kg m−3) 290 310 320 330 340 350

N. spruce

128

19.3 (8.4)

8.55 (1.68) C18

378 (36.6)

345 C22

31.14 (8.99)

19.13 C18

C18

Red cedar

115

19.0 (9.4)

7.44 (1.66) C14

365 (30.3)

318 C16

30.06 (8.03)

16.33 C16

C14

N. fir 126

15.0 (8.4)

7.71 (2.27) C16

358 (36.7)

324 C18

31.10 (13.12)

14.77 C14

C14

W. hemlock 138

18.6 (9.4)

8.33 (2.04) C16

444 (38.8)

385 C30

34.51 (10.65)

18.19 C18

C16 1Moore, J.R. et al. Within- and between-stand variation in selected properties of Sitka spruce sawn timber in the UK: implications for segregation and grade recovery. Annals of Forest Science, 2013, 70(4): 403-414.



0

0.01

0.02

0.03

0.04

0.05

0 10 20 30 40 50 60 70 80

Frequency

Mean Stiffness

5th percentile Strength &

Density

•  We grade populations, not individual pieces

A few notions on grading

Variations: !  Between species !  Between origins !  Between trees !  Within a tree !  With age


Centre for Wood Science and Technology Yields with a rotation age of 45 years

C14 C16 C18 C20 C22 C24

Sitka spruce 100% 100% 92% 75% 58% 30%

Norway spruce 100% 100% 100% 81% 62% 30%

Western hemlock 100% 100% 95% 81% 67% 40%

Noble fir 100% 96% 77% 62% 49% 30%

Western red cedar 100% 94% 56% 38% 25% 11%



This project is funded by:

!  The Scottish Forestry Trust

!  Natural Resources Wales

!  Forestry Commission Scotland

!  Thank you to Forest Research and Edinburgh Napier University for providing staff and resources

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CentreforWoodScienceandTechnology( Timber … gil-moreno timber... · Authors: David Gil-Moreno, Dan Ridley-Ellis & Paul McLean Timber properties of