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
Ins$tute for Sustainable Construc$on
Centre for Wood Science and Technology
The world we are in
Ins$tute for Sustainable Construc$on
Centre for Wood Science and Technology
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
Ins$tute for Sustainable Construc$on
Centre for Wood Science and Technology
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
Ins$tute for Sustainable Construc$on
Centre for Wood Science and Technology
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
Ins$tute for Sustainable Construc$on
Centre for Wood Science and Technology
Ins$tute for Sustainable Construc$on
Centre for Wood Science and Technology
Ins$tute for Sustainable Construc$on
Centre for Wood Science and Technology
Ins$tute for Sustainable Construc$on
Centre for Wood Science and Technology
Ins$tute for Sustainable Construc$on
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
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Centre for Wood Science and Technology Material and Methods ! Processing into battens; drying;
Cambial age = 45
Ins$tute for Sustainable Construc$on
Centre for Wood Science and Technology Material and Methods ! Destructive four point bending, EN408:2010
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Centre for Wood Science and Technology
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.
Ins$tute for Sustainable Construc$on
Centre for Wood Science and Technology
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
Ins$tute for Sustainable Construc$on
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%
Ins$tute for Sustainable Construc$on
Centre for Wood Science and Technology
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