Analysis of Taper Responses to Sulfur Treatments in Coastal Oregon Doug-fir
Western Mensurationists’ 2006 Annual Meeting June 19, 2006
Nicole YoungerMS student,
Department of Forest Resources,Oregon State University
And Hud
What is Swiss Needle Cast Disease?• Blame the Swiss!
• Tree rust caused by a fungus
• Clogs stomata with pseudothecia
• Pseudothecia count increases with age of needle
• Needle eventually dies
• Needle retention 3-4 years in healthy trees, two or less in infected trees
3rd year 2nd yearCurrent year
Volume loss estimated at 23% with a high of 50% in the severely infected stands.
Spread over the target population of 187,000 acres, this means that
approximately 40MMBF were lost to this disease in 1996 alone!
(Maguire et al. 1998)
What is Swiss Needle Cast Disease?
What do we do now?!?
• Essential ingredient for plant nutrition --component of amino acids, proteins, fats, and other plant compounds
• In the soil, sulfur (SO4) also plays a pivotal role in the movement of acidic cations such as H+, and Al3+, as well as nutrient cations such as Ca2+ and Mg2+ (Johnson and Mitchell 1998) Critical C/N ratio in the OR coast range
• Factory emmisions are being tightened resulting in less atmosheric Sulfur
• Recent discoveries of plants actually producing sulfur as a natural fungal defense (Williams and Cooper 2003)
• “Considered essentially non-toxic by ingestion” (MSDS)
Three treatments:
1. Sulfur
2. Sulfur and nutrients
3. Control
10 plots/treatment
4 Trees/plot
(40 trees per treatment, 120 total)
Experimental Site
Nilsen Creek, Lincoln County, Oregon
Aerial applications took place 2000-2004
Ca prils
• Planted in 1983 with all the same stock, 430 TPA
• Total height (H) ranged from 16.92 – 26.20 meters, with the mean at 21.53 m (std dev 1.61 m)
• DBH outside bark (D) ranged from 104.50 – 336.00 mm with a mean of 208.87 mm (std dev 42.25 mm)
• Early vegetation control, hack and squirt of hardwoods pre-canopy closure
• Slope/elevation/aspect all similar between treatment sites
Felled in April 2005
Trees measured and disks collected July – August 2005
Stump disk
DBH disk
Disk 1
Crown base disk
Disk 2
Approximately 9 disks per tree were taken (1063 disks total) Diameter (inside and outside bark), height of disk
as well as sapwood area of CB
disk recorded
6” DBH 1 2 CB 3 4 5
Each tree measured for:
Total height, crown ratio, lowest live branch location, crown width
Needle characteristics (LA, width, length)
control – sulfur comparison p-value = 0.51
control – sulfur and nutrient comparison p-value = 0.85
Cont r ol Sul f _ nu Sul f ur
0
1
2
3
4
5
Crown
Width
Control Sulfur and Nutrient Sulfur
control – sulfur comparison p-value = 0.94
control – sulfur and nutrient comparison p-value = 0.67
Cont r ol Sul f _nu Sul f ur
0
10000
20000
30000
40000
Sapwood
area
Control Sulfur and Nutrient Sulfur
control – sulfur comparison p-value = 0.14
control – sulfur and nutrient comparison p-value = 0.16
Cont r ol Sul f _nu Sul f ur
0. 2
0. 3
0. 4
0. 5
0. 6
0. 7
0. 8
Crown
ratio
Control Sulfur and Nutrient Sulfur
control – sulfur comparison p-value = 0.998
control – sulfur and nutrient comparison p-value = 0.073
Cont r ol Sul phur Sul phur _ Li me
0
200
400
600
800
1000
Total
Foliar
Weight
Control Sulfur Sulfur and Nutrient
control – sulfur comparison p-value = 0.276
control – sulfur and nutrient comparison p-value = 0.028
Cont r ol Sul phur Sul phur _ Li me
2. 50
2. 75
3. 00
3. 25
3. 50
3. 75
4. 00
Foliar
Retention
Control Sulfur Sulfur and Nutrient
control – sulfur comparison p-value = 0.0039
control – sulfur and nutrient comparison p-value = <0.0001
TreatmentLS mean (mm) 95% Conf. Int.
Control 3.26 3.12 – 3.39
Sulfur/Nutrient 3.70 3.57 – 3.84
Sulfur 3.54 3.40 – 3.67
“pre-treat” increment = (1996+1997+1998+1999)/4“post-treat” increment = (2001+2002+2003+2004)/4
Ignoring autocorrelations in taper data sets causes (Kozak 1997):
1. Estimators which no longer have a minimum variance property
2. Underestimation of standard errors on parameter estimates
3. Unreliable tests of significance
Question:
Does ignoring these autocorrelations in my taper dataset cause tests of treatment effects to be falsely significant?
X a HDb b Zb 0.001)ln(Zb ZbD
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Where: di = diameter inside bark of ith diskhi = height from ground of ith diskH = total height of treeZ = hi/Hp =(HI/H)*100D = diameter outside bark at breast heighta0 – a2 and b1 – b5 = parameters to be estimated
X = pH
hi
1
1
Properties of Model:
1. di = 0 when hi/H = 1.0
2. di = DI (estimated dib at inflection point) when HI/H = P
3. function changes direction when hi/H = p
X a HDb b Zb 0.001)ln(Zb ZbD
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0 5 10 15 20 25
hi
0
100
200
300
400
di
ControlSulf_nutrSulfur
a0 a1 a2 b1 b2 b3 b4
a1 -0.999
a2 0.984 -0.989
b1 0.007 -0.001 -0.003
b2 -0.024 0.017 -0.018 -0.91
b3 0.023 -0.015 0.014 0.883 -0.987
b4 -0.016 0.008 -0.006 -0.937 0.982 -0.988
b5 -0.049 0.053 -0.07 0.392 -0.11 0.151 -0.275
Parameter Correlation Matrix
X a HDb b Zb 0.001)ln(Zb ZbD
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Value Std.Error t-value p-value a0 3.1370 1.2648 2.480 0.0133a1 0.7066 0.0923 7.653 <.0001a2 1.0009 0.0004 2332.256 <.0001
After Removal of a2 parameter:
a0 1.3607 0.0993 13.6992 <.0001a1 0.8989 0.0135 66.6847 <.0001
X HDb b Zb 0.001)ln(Zb Zb
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X IbIbHDb b Zb 0.001)ln(Zb Zb
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Treatment Indicators added to exponent:
IS = 1 if treatment = Sulfur, 0 otherwiseISN = 1 if treatment = Sulfur and Nutrient, 0 otherwise
Sulfur treatment insignificant (p = 0.3588)Sulfur and nutrients treatment does effect taper! (p = 0.0017)
Z
dC
0.0 0.2 0.4 0.6 0.8 1.0
0.0
0.5
1.0
1.5
2.0
0.0
0.2
0.4
0.6
0.8
1.0
0 2 4 6
Lag
Au
toco
rre
latio
n
-50
0
50
100
0 100 200 300 400
di
Re
sid
ua
ls
-50
0
50
100
0.0 0.2 0.4 0.6 0.8 1.0
Z
Re
sid
ua
ls
-50
0
50
100
0.0 0.5 1.0 1.5
X
Re
sid
ua
ls
-50
0
50
100
100 150 200 250 300
D
Re
sid
ua
ls
Sulfur treatment still insignificant (p = 0.6689 vs. p = 0.3588 without car(1))
Sulfur and nutrient treatment still significant (p = 0.0010 vs. p = 0.0017 without car(1))
X IbIbHDb b Zb 0.001)ln(Zb Zb
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Sulfur treatment still insignificant (p = 0.1230)
Sulfur and nutrient treatment still significant (p = 0.0135)
X IbIbHDb b Zb 0.001)ln(Zb Zb
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Sulfur treatment still insignificant (p = 0.0930)
Sulfur and nutrient treatment more significant (p = <0.0001)
Model df AIC BIC log LikelihoodGNLS 10 8447.159 8496.847 -4213.579 GNLScar 12 8370.610 8430.236 -4173.305 NLME 11 8460.590 8515.248 -4219.295 NLMEcar 13 8452.210 8516.805 -4213.105
X IbIbHDb b Zb 0.001)ln(Zb Zb
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Test log likelihood ratio p-valueGNLS vs GLNScar 80.54881 <.0001GNLScar vs NLME 91.98045 <.0001NLME vs NLMEcar 12.38081 0.002GNLS vs NLME 11.43164 0.0007GNLScar vs NLMEcar 79.59964 <.0001
X IbIbHDb b Zb 0.001)ln(Zb Zb
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Sulfur/
Sulfur Nutrient
GNLS -0.01 -0.04
GNLS car(1) -0.01 -0.04
NLME -0.02 -0.04
NLMEcar(1) -0.02 -0.05
Parameter estimates experienced little change:
X IbIbHDb b Zb 0.001)ln(Zb Zb
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P-values of treatment parameters show no clear patterns:
X IbIbHDb b Zb 0.001)ln(Zb Zb
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Sulfur/
Sulfur Nutrient
GNLS 0.3588 0.0017
GNLS car(1) 0.6689 0.0010
NLME 0.1230 0.0135
NLMEcar(1) 0.0930 <0.0001
• Parameters relatively unchanged as hypothesized
• Standard errors of treatment parameters fluxuated, did not necessarily become less significant as expected
• Adding car(1) to GNLS or NLME significantly fit data better
• Adding random tree effect also helped to fit data significantly better
Special Thanks
Starker Forests Inc. for project funding supplying treated field sites
Sean Garber for sharing his S-Plus knowledge and taper enthusiasm
Temesgen Hailemariam for his guidance and the opportunity to attend this meeting
Works Cited
• Johnson DW, Mitchell MJ (1998) Responces of forest ecosystems to changing sulfur inputs. In 'Sulfur in the Environment'. (Ed. D Maynard) pp. 219-262. (Marcel Dekker, Inc.: New York)
• Maguire DA, Kanaskie A, Johnson R, Johnson G, Voelker W (1998) 'Swiss needle cast growth impact study: report on results from phases I and II.' College of Forestry, Oregon State University, Corvallis, OR.
• Material Safety Data Sheets (2005)
• Williams JS, Cooper RM (2003) Elemental sulfur is produced by diverse plant families as a component of defense against fungal and bacterial pathogens. Physiological and Molecular Plant Pathology 63, 3-16.