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Breeding for Wood Quality; Acoustic Tools and Technology
2007 AFG & IUFRO SPWG Joint Conference Hobart, Tasmania – April 2007
Peter Carter – Chief Executive, Fibre-gen
Breeding for Wood Quality; Acoustic Tools and Technology 2007 AFG - - PowerPoint PPT Presentation
Breeding for Wood Quality; Acoustic Tools and Technology 2007 AFG & IUFRO SPWG Joint Conference Hobart, Tasmania April 2007 Peter Carter Chief Executive, Fibre-gen 1 Contents Why acoustics? How acoustics work
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Peter Carter – Chief Executive, Fibre-gen
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– Global emphasis on structural and appearance qualities – Age of clearfall declining, log quality more variable – Tree breeding has improved volume more than quality
– Development of ‘verified visual’ grading (sample proof tested) – Price differential in lumber and engineered wood markets – Mills sensitive to stiffness of smaller diameter young wood
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What is stiffness worth – a couple of examples
– VSG8 lumber premium is NZ$100/m3 ($450 vs $350) – At 55% conversion, 80% structural, equates to $36/m3 log – At 600m3/ha, 70% sawlog, 27 yrs, 8%, equates to $1,893/ha
– MGP8 lumber premium is NZ$250/m3 – 0.1km/sec gives 5% more MGP8, worth $12.50/m3 – At 600m3/ha, 70% sawlog, 27 yrs, 8%, equates to $657/ha
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What is stiffness worth – more examples
– Structural £150, Industrial £100
– MSR 1,450kr, Visual structural 1,350kr
– MSR $350, Visual structural $310 – LVL $350, Ply $230
– MSR $195, Visual structural $178 Absolute differences vary with market conditions – premiums remain
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Other values are significant too
– R2 in range 0.8 – 0.9 – MFA is key predictor of solid wood stability and fibre stiffness
– Fibre length and paper strength – Coarseness and sheet quality – Energy consumption and yield
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– Less than 1 minute/tree for testing – Wireless, with no cables to tangle or fail – Quick and easy insertion and removal of probes – No cores needed – No significant damage to young trees
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high
SD 0.2
delivered gain is 0.18 and 0.26 respectively
$1,180 and $1,700/ha NPV at time of planting
Normal Distribution
0% 2% 4% 6% 8% 10% 12% 14%
2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8
Velocity (km/sec)
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frequency (2nd harmonic) and length
frequency from hammer blow
3.3
length velocity = 2 x length / time
stiffness density x velocity ≈
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log measure
and visual output, interface to PDA
level
Acoustic speed - standing tree vs log 6000 7000 8000 9000 10000 11000 12000 13000 14000 6000 8000 10000 12000 14000 16000 ST300 prototype on tree (ft/s) HM200 on log (Director) (ft/s)
Sitka spruce Western hemlock Jack pine White birch Ponderosa pine R
2 = 0.925Source: X Wang et al, University of Minnesota
Juvenile Wood
15 yrs 25 yrs 35 yrs
Juvenile Wood
15 yrs 25 yrs 35 yrs
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precision – Calibration against absolute standard – Filters enhance precision
TOF vs Distance (Brass Bar)
y = 0.2941x + 0.2476 R2 = 0.9997
50 100 150 200 250 300 350 400 450 500 500 1000 1500
Distance (mm) TOF (us) Recorded Time of Flight Variation
(SD 3.5 vs 7.5)
300 320 340 360 380 400 420 440 460 480 500 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Sample number Time of Flight (micro-sec)
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– Variation around stem – Knot location – Transverse – Compression wood – Hit variability
density coring
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Location/s on tree taps R2 Upper side 3 0.44 Upper side 3 0.48 Upper side 3 0.43 Upper side (A) 9 0.50 Lower side (B) 9 0.45 Random side (D) 9 0.60 Mean A+B 18 0.61 Mean A+D 18 0.62 Mean A+B+D 27 0.67
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radiata pine
between standing tree and log velocity improves as sample intensity increases
Standing Harvesting Stem Log Log Deck Lumber or Tree Processor to Mill Veneer ST300 PH330 HM200 HM200 LM600 Grader >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>>
Correlation vs number of samples
0.00 0.20 0.40 0.60 0.80 1.00 10 20 30 40 50 Number of samples Correlation (R
2)
Rx 0031 Rx 0035
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radiata pine
relationship is stable, new vs old
higher than ‘generic’ field
based dataset
McVicars Validation HM vs ST
y = 1.4316x - 0.2893 R2 = 0.5121
3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6 4.8 5.0 2 2.5 3 3.5 4
HM velocity (km/sec) ST velocity (km/sec)
Rx0031 Rx0035 Generic relationship Version 1 ST300 (cap) Linear (Rx0035) Linear (Rx0031) Linear (Generic relationship) Linear (Version 1 ST300 (cap))
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would require – Average log velocity 2.8km/sec (allowing 0.1km/sec for SE
– Green density 1000kg/m3
formation, target 2.8 km/sec although 2.6 may be adequate for structural minimum (5.6 GPa)
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In general
But
Temperature Effect on Acoustic Velocity of Green Board
200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400 3600 3800 4000Board Temperature (C) Acoustic Wave Velocity (m/s)
Stack 6 (50 boards) Stack 2 (50 boards)V = 2365 - 17.69T (T ? 0 °C) V = 2365 - 41.42T (T ? 0 °C)
Density (MC ) adjusted acoustic speed
2 2.5 3 3.5 4 4.5 5Source: L Bjorklund, VMR, SDC Source: P Harris, IRL Source: X Wang, University of Minnesota
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greatest variation is between stems
Source: X Wang et al, University of Minnesota
R adiata Pine - Log velocity within stem
2.50 3.00 3.50 4.00 5 1 1 5 20 25 30 Distance up stem (m) Velocity (km/ sec) Average 3.2 km/ sec Average + 2 x SD Average - 2 x SD Stand Mean 3.2
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Location of boards in the log
Average stiffness of wood in boards up the stems
Average stiffness of lumber cut from some 60 trees. Note the low stiffness at the base of the tree, in the butt logs. Why not cut a short, 2.5 m butt log?
1st log 2nd log 3rd log
Ping Xu, 2002
Source: J Walker, University of Canterbury
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In general
But
Log age vs. average acoustic velocity
R
2 = 0.66 2.50 2.60 2.70 2.80 2.90 3.00 3.10 3.20 3.30 3.40 3.50 18 20 22 24 26 28 30 32 34Log age (years) Stand Linear (Stand)
Velocity vs Stand A ge
2.80 2.90 3.00 3.10 3.20 3.30 3.40 3.50 3.60 3.70 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37Age (years) Velocity (km/sec) Mean Velocity (50% oldest age) = 3.43 Mean Velocity (50% highest V) = 3.37 Benefit = 0.06km/sec
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