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Vector Analysis: Does it really predict growth response?. Mariann Johnston, SUNY-ESF Ranger School. Shoestring Satellite Experiment: The Adirondack Screening Trials. Individual tree fertilization trials James F. Dubuar Memorial Forest, Adirondack Park 2 Species
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Vector Analysis: Does it really predict growth response? Mariann Johnston, SUNY-ESF Ranger School
Shoestring Satellite Experiment:The Adirondack Screening Trials • Individual tree fertilization trials • James F. Dubuar Memorial Forest, Adirondack Park • 2 Species • Sugar maple (dom/codom, ~30 cm dbh) • Am. beech (intermediate, ~10 cm dbh) • 6 Treatments screened
Shoestring Satellite Experiment:The Treatments • Control • N1: 30 N (urea) • N1P1: 30 N + 30 P (MAP + urea) • N2: 200 N • N2P2: 200 N + 100 P • N2P2KB: 200 N + 100 P + 200 K + 3 B Shoestring Project Prelim One-time application
Timeline • 2010 • May: Fertilized, Measured • July-Aug: Foliage collected, dried, weighed • 2011 • Feb-Apr: ICP and C/N analyses • July: Vector analyses presented • Nov: Remeasurements • Today: Two-Year Basal Area Response
Vector Analysis • Foliar diagnostic technique • Predicts nutrient deficiencies • Assumes that foliage response is a predictor of tree yield response • Did it work?
Sugar Maple • Vector analysis said: • Response to N2P2KB will occur • N, P, K were deficient
Sugar Maple Growth Response No significant differences between treatments
American Beech • Vector analysis said: • No growth response to any fertilization treatment will occur
Beech Growth Response p-values: 0.003 0.02 0.07 0.09 0.17
Conclusions • Did vector analysis predict growth response? • No, not really (2-yr BA) • But . . . • Foliage-damaging spring freeze occurred at time of fertilization • Height, volume growth were not analyzed • Continue monitoring for future responses
Conclusions • Beech responded to fertilization! • Intermediate crown class, understory cohort • Is beech a ‘nutrient hog’? • What are the ecological implications?
Graphical Vector Analysis 100 Relative Foliage Biomass E: Toxicity D: Luxury Consumption C: Deficiency B: No Change F: Antagonism A: Dilution
Sugar Maple Growth • Mean dbh Yr 0: 34.6 cm • Mean dbh Yr 2: 35.0 cm • Average BA response of 2.4% • No differences between treatments were detected • Predicted growth responses not apparent in diameter response
Beech Growth • Mean dbh Yr 0: 9.9 cm • Mean dbh Yr 2: 10.7 cm • Average BA response of 18.1% • All treatments showed significant (p < 0.05) growth compared to control except for N2 (200 kg N)