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Effect of Site, Age, and Treatments of Type II
Installations on Standing Tree Acoustic Velocity
David Briggs, Eric Turnblom, Gonzalo Thienel
File: Agenda_2020_TreeLogMill_Study Plan_Mar_6_06.pptDate: May 24, 2007
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Introduction
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AGENDA 2020 Project
“Non-destructive evaluation of wood quality in standing Douglas-fir trees and logs”
David Briggs[1], Eini Lowell[2], Eric Turnblom[1], Bruce Lippke[3], Peter Carter[4]
[1] Stand Management Cooperative (SMC) University of Washington, Seattle, WA[2] USFS PNW Research Station, Portland, OR
[3] Rural Technology Initiative (RTI), University of Washington, Seattle, WA[4] Manager Resource Technology & Commercialization, CHH Fibre-Gen, New Zealand
Study Background:
Issue:Lack of information may lead to use of cultural treatments with detrimental effects on future wood quality and product value. New field tools are now available that allow rapid non-destructive assessment of one measure of wood quality (stiffness) in standing trees and logs.
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Objective 1 :• Evaluate stiffness along the tree to product chain to
Define relationships between stiffness of lumber or veneer within a log, the stiffness of the log, and the stiffness of the parent tree
Assess the effect of treatment and stand variables on these relationships
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Study Cooperators
University of Washington College of Forest ResourcesUSDA Forest Service, PNW Research Station USDA Forest Service, Forest Products LaboratoryCHH Fibre-Gen, New Zealand Green Diamond Resource Company Port Blakely Tree Farms WA State Department of Natural Resources Weyerhaeuser Company
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This Presentation
• Analysis of standing tree data from Douglas-fir • Collected in September 2006
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Objective : What are the influences of thinning regimes, stand age, DBH, stems per acre, and site class on the acoustic time of flight (SWT) in stand Douglas-fir trees?
• Note: velocity (m/sec) and time-of-flight (stress-wave-time, SWT) (sec/m) are reciprocals
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Previous studies :
• Thinning effect lower acoustic velocity in Sitka Spruce (citation reference)higher acoustic velocity in Douglas-fir (citation reference)
• DBH effectWithin a given stand there is a weak negative relation
between acoustic velocity and dbh (therefore a weak positive relation between SWT and dbh)
• No information on effects of site• Expect an effect of age (trees add denser, stiffer mature
wood as they age)
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Sample Stands : SMC Type II Installations
Inst # Name Owner Location Age (2005) SI (King) QMD, in HT40, ft803 Beeville Loop Green Diamond Shelton, WA 50 140 14 126805 Pilchuck Bridge WADNR Mt Vernon, WA 35 135 12 105807 Viola Port Blakely Estacada, OR 33 115 11 82808 M21 Road Weyerhaeuser Salem, OR 48 88 13 102
SMCType II Installations for Tree to log to mill test on NDT tools
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Stress-wave-time (SWT) of standing trees• 4 installations x 5 plots
= 20 plots– One plot at one installation not
usable prior wind damage
• 52 trees in a stem-mapped circular plot
• TreeSonic time-of-flight μsec (SWT) over 1 m distance
• 3 readings at each location
• 3 equidistant locations on circumference of each tree
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Results• Within-installation
Treatment plot differences Trends with dbh within treatment plots
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• Ho: The average SWT within the plots in a particular installation are all the same.
µ1 = µ2 = µ3 = µ4 = µ5
• Ha: At least there is one inequality in the average SWT between the plots in a particular installation.
Within Installation Treatment Plot Differences
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One-Way ANOVA
ANOVA (803)Source of Variation SS df MS F P-value F critBetween Plots 2579.977 4 644.9942 4.392958 0.001883 2.407043Within Plots 37440.27 255 146.8246
Total 40020.25 259
ANOVA (805)Source of Variation SS df MS F P-value F crit
Between Plots 43049.41 4 10762.35 14.18016 2.04E-10 2.408792Within Plots 184430.3 243 758.9723
Total 227479.7 247
ANOVA (807)Source of Variation SS df MS F P-value F crit
Between Plots 12067.71 4 3016.927 18.19699 3.92E-13 2.407751Within Plots 41448.16 250 165.7926
Total 53515.87 254
ANOVA (808)Source of Variation SS df MS F P-value F crit
Between Plots 4115.218 3 1371.739 9.000855 1.29E-05 2.650209Within Plots 30175.4 198 152.401
Total 34290.61 201
We reject null hypothesis at α = 0.95
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SWT vs. Stems/Acre
Installation805 807 808 803
S.I. 135 115 88 140Age 35 33 48 50
Inst 805plot 2 3 5 1 4
code c e b d a
Inst 807plot 2 4 5 3 1
code c d e b a
Inst 808plot 2 3 1 5
code c d b a
Inst 803plot 4 3 1 2 5
code d c b a e
• Are differences due to chain-saw effect of thinning or due to the growth response after thinning?
SWT as a function of stem per acre
235
255
275
295
70 120 170 220 270 320 370 420
stem per acre
SW
T (
mse
c/m
)
805 807 808 803
2
3
1
5
4
2 5
4
1
3
5
23
15
43
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Thininning code
code meaning
a no treatment (defined as control)b repeated thinning: RD55-RD35, RD55-RD40, subsequent RD60-RD40c repeated thinning: RD55-RD30, subsequent RD50-RD30d minimal thinning: RD55-RD30, no further thinninge Delayed thinning: RD65-RD35, no further thinning
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SWT vs DBH by Installation
803 Stems/acre SI Age DBH (mean) Thinning code1 166 140 50 14.27 b2 208 140 50 13.93 a3 132 140 50 16.26 c4 116 140 50 16.73 d5 226 140 50 13.31 e
In general increased SWT is weakly associated with increased DBH; hence velocity (stiffness) is weakly decreasing with increased dbh as others have found
SWT vs DBH (Installation 803)
200220240260280300320340360380400
5 9 13 17 21 25
DBH (Inches)
SW
T (
msec/m
)
Plot 1 Plot 2 Plot 3 Plot 4 Plot 5
SWT vs DBH (Installation 808)
200220
240260
280300
320340
360380
400
5 9 13 17 21 25
DBH (Inches)
SW
T (
msec/m
)
Plot 1 Plot 2 Plot 3 Plot 5
808 Stem/acre SI Age DBH(mean) Thinning code1 142 88 48 15.84 b2 98 88 48 18.37 c3 118 88 48 17.22 d5 258 88 48 15 a
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SWT vs DBH by InstallationHowever, younger installations seem to have more variability. Why?
SWT vs DBH (Installation 805)
200220240260280300320340360380400
5 9 13 17 21 25
DBH (Inches)
SW
T (
msec/m
)
Plot 1 Plot 2 Plot 3 Plot 4 Plot 5
805 steam/acre SI Age DBH (mean) Thinning code1 172 135 35 12.82 d2 88 135 35 15.57 c3 142 135 35 13.5 e4 280 135 35 12 a5 162 135 35 13.25 b
SWT vs DBH (Installation 807)
200220240260280300320340360380400
5 9 13 17 21 25
DBH (Inches)
SW
T (
msec/m
)
Plot 1 Plot 2 Plot 3 Plot 4 Plot 5
807 Stem/acre SI Age DBH (mean) Thinning code1 434 115 33 9.45 a2 158 115 33 11.46 c3 332 115 33 10.21 b4 288 115 33 10.5 d5 292 115 33 10.27 e
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Results• Between-installations
Site index (King) Stand Age
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STAND AGE
Time of flight as a function of stand age
245
250
255
260
265
270
275
280
285
20 25 30 35 40 45 50 55
stand age (years)
SW
T (
msec/m
)
807
805
808
803
• Older stands have lower SWT higher velocity higher stiffness
SITE INDEX (King)
• SI is that given by landowner when established; may be poor reflection of current stand
Time of flight as a function of SI (King)
245
250
255
260
265
270
275
280
285
70 90 110 130 150
SI (King)
SWT
(mse
c/m
)
803
805
807808
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Next Steps
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Next Steps
• Find the source (s) of variation in SWT within and between plots (Thinning regimes ???)
• Get better estimates of site index• A general model SWT = f(age, site index,
stocking/thinning level)
• Switch to the 12 trees harvested from each plot Relationships between acoustic (TreeSonic) of standing
tree and its merchantable bole (HM-200), woods logs, and mill-length logs
Include wood density. Cookies from each end of every log
Include knot data. Relation between TreeSonic and ST-300 Include results of veneer & lumber tests
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References• Briggs, D.G. and W.R. Smith. 1986. Effects of Silvicultural Practices on Wood Properties--A Review. In:
Douglas-fir: Stand Management for the Future. Oliver, C.D., D.P. Hanley, and J.A. Johnson, eds., June 18-20, 1985. College of Forest Resources, University of Washington, Seattle, WA. Contrib. No. 55. pp. 108-117.
• Carter, P. D. Briggs, R.J. Ross, X. Wang 2005. Acoustic Testing to Enhance Western Forest Values and Meet Customer Wood Quality Needs. In Harrington Constance A., Schoenholz, Stephen H. eds.; “Productivity of Western Forests: A Forest Products Focus” Gen. Tech. Rep. PNW-GTR-642; U. S. Department of Agriculture, Forest Service Pacific Northwest Research Station, Portland OR. pp 121-129.
• Wang, X., R.J. Ross, M. McClellan, R.J. Barbour, J.R. Erickson, J. W. Forsman, G.D. McGinnis. 2001. Nondestructive Evaluation of Standing Trees with a Stress Wave Method. Wood & Fiber Science 33(4): 522-533.
