Nutrient Limitations to Growth of Nutrient Limitations to Growth of Westside Douglas-fir Forests: Westside Douglas-fir Forests: A Look Beyond Nitrogen A Look Beyond Nitrogen Doug Maguire Doug Maguire Department of Forest Science Department of Forest Science Oregon State University Oregon State University Steve Perakis Steve Perakis FRESC FRESC USGS USGS Rick Fletcher Rick Fletcher Department of Forest Resources Department of Forest Resources Oregon State University Oregon State University Doug Mainwaring Doug Mainwaring Department of Forest Science Department of Forest Science Oregon State University Oregon State University
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Nutrient Limitations to Growth of Westside Douglas-fir Forests: A Look Beyond Nitrogen
Nutrient Limitations to Growth of Westside Douglas-fir Forests: A Look Beyond Nitrogen. Doug Maguire Department of Forest Science Oregon State University Steve Perakis FRESC USGS Rick Fletcher Department of Forest Resources Oregon State University Doug Mainwaring - PowerPoint PPT Presentation
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Nutrient Limitations to Growth of Nutrient Limitations to Growth of Westside Douglas-fir Forests: Westside Douglas-fir Forests:
A Look Beyond Nitrogen A Look Beyond Nitrogen
Doug MaguireDoug MaguireDepartment of Forest ScienceDepartment of Forest Science
Oregon State University Oregon State University
Steve PerakisSteve PerakisFRESCFRESCUSGS USGS
Rick FletcherRick FletcherDepartment of Forest ResourcesDepartment of Forest Resources
Oregon State University Oregon State University
Doug MainwaringDoug MainwaringDepartment of Forest ScienceDepartment of Forest Science
Oregon State UniversityOregon State University
BackgroundBackground
• Trials originally of interest to members of the Trials originally of interest to members of the Swiss needle cast cooperativeSwiss needle cast cooperative– Fertilization has been investigated as one of the tools Fertilization has been investigated as one of the tools
to combat SNCto combat SNC– Previous SNC fert studies have generally included Previous SNC fert studies have generally included
N, either as single-nutrient treatments or blends:N, either as single-nutrient treatments or blends:• Menasha trialsMenasha trials• Plum Creek trialsPlum Creek trials• VMRC trialsVMRC trials• Balanced Fertilizer trialsBalanced Fertilizer trials
F R = 1 . 5
F R = 2 . 5
F R = 3 . 5
-20
-10
0
10
20
30
40
1 1.2 1.4 1.6 1.8 2 2.2 2.4
% foliar N
5-yr
Vol
gro
wth
cha
nge
with
trt (
%)
BackgroundBackground
• Studies suggest that nitrogen may be Studies suggest that nitrogen may be problematic in SNC-infected standsproblematic in SNC-infected stands– Lack of response to N in previous fert trialsLack of response to N in previous fert trials– Negative correlation between foliage retention and Negative correlation between foliage retention and
foliar Nfoliar N– N from fertilization was found to be directly N from fertilization was found to be directly
responsible for increased the fungal nitrogen levels responsible for increased the fungal nitrogen levels and fungal fruiting, and thus, disease severity and fungal fruiting, and thus, disease severity
Leaf Retention as a Function of Leaf N Concentration
0
1
2
3
4
0.8 1 1.2 1.4 1.6 1.8Leaf Nitrogen, %
Leaf
Ret
entio
n, Y
ears
BackgroundBackground
• Studies suggest that nitrogen may be Studies suggest that nitrogen may be problematic in SNC-infected standsproblematic in SNC-infected stands– Lack of response to N in previous fert trialsLack of response to N in previous fert trials– Negative correlation between foliage retention and Negative correlation between foliage retention and
foliar Nfoliar N– N from fertilization was found to be directly N from fertilization was found to be directly
responsible for increased the fungal nitrogen levels responsible for increased the fungal nitrogen levels and fungal fruiting, and thus, disease severity and fungal fruiting, and thus, disease severity
BackgroundBackground
• Proposed study went through several iterations Proposed study went through several iterations to meet the needs of participantsto meet the needs of participants– How to include non-SNC Coop membersHow to include non-SNC Coop members– Fixed area vs. individual tree plotsFixed area vs. individual tree plots– TreatmentsTreatments
Fertilization Trials
16 locations, 12 landowners
Cascade Timber Giustina Green Diamond (2) Hampton (2) Lone Rock Menasha (2) ODF OSU Port Blakely Starker West Fork Timber Weyerhaeuser (2)
Study design
• Individual tree plots (1/40th acre)
• 10 plots per treatment
• 5, 7, or 8 treatments per site
• 50, 70, or 80 plots per site 18.6 ft
Target stands
• Target stands– 20 yrs of age (+/- 5 yrs)– 300 tpa (+/- 100 tpa)– No pct or fertilization in last 8 years– < 20% salal cover– Good road access– Relatively flat– Limited brush cover– Nearby donut source
Target stands
• Target stands– 20 yrs of age (+/- 5 yrs)– 300 tpa (+/- 100 tpa)– No pct or fertilization in last 8 years– < 20% salal cover