Presentation on theme: "Analysis of Taper Responses to Sulfur Treatments in Coastal Oregon Doug-fir Western Mensurationists’ 2006 Annual Meeting June 19, 2006 Nicole Younger MS."— Presentation transcript:
Analysis of Taper Responses to Sulfur Treatments in Coastal Oregon Doug-fir Western Mensurationists’ 2006 Annual Meeting June 19, 2006 Nicole Younger MS 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 3 rd year 2 nd year Current 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?
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)
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?
Where: d i = diameter inside bark of i th disk h i = height from ground of i th disk H = total height of tree Z = h i /H p =(HI/H)*100 D = diameter outside bark at breast height a 0 – a 2 and b 1 – b 5 = parameters to be estimated X =
Properties of Model: 1.d i = 0 when h i /H = 1.0 2.d i = DI (estimated dib at inflection point) when HI/H = P 3.function changes direction when h i /H = p
Value Std.Error t-value p-value a 0 3.1370 1.26482.480 0.0133 a 1 0.7066 0.0923 7.653 <.0001 a 2 1.0009 0.0004 2332.256 <.0001 After Removal of a2 parameter: a 0 1.3607 0.0993 13.6992 <.0001 a 1 0.8989 0.0135 66.6847 <.0001
Treatment Indicators added to exponent: I S = 1 if treatment = Sulfur, 0 otherwise I SN = 1 if treatment = Sulfur and Nutrient, 0 otherwise Sulfur treatment insignificant (p = 0.3588) Sulfur and nutrients treatment does effect taper! (p = 0.0017)
P-values of treatment parameters show no clear patterns: Sulfur/ SulfurNutrient GNLS0.35880.0017 GNLS car(1)0.66890.0010 NLME0.12300.0135 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.