Presentation on theme: "Can leaf mass & foliar nutrient concentration explain species growth rates in northern hardwood stands? Presented by: Shinjini Goswami Graduate Research."— Presentation transcript:
Can leaf mass & foliar nutrient concentration explain species growth rates in northern hardwood stands? Presented by: Shinjini Goswami Graduate Research Assistant Miami University, OH Contact:
Co-limitation Can arise in couple ways- 1. Productivity of all trees respond additively to N+P additions OR 2. Productivity of one species might respond to N whereas another might respond to P: Community level co-limitation Broad question- Species specific growth responses to nutrient availability N or P or Ca or all????
Introduction Growth efficiency- Trees with high efficiency accumulate more biomass per unit leaf mass Measured as productivity per unit leaf mass Expect it to increase with availability of the limiting nutrient Foliar N:P ratios indicate nutrient limitations &/or co-limitation; 20 indicates P limitation Koerselman 1996, Gusewell 2004 If species differ in growth efficiencies relative to different nutrients, could contribute to co-limitation
Species composition in MELNHE stands
Foliar N:P by species in mid and old stands (different nutrient status) Green- mid Red- old No specific pattern
I hypothesize that Beech is limited by P in the old stands.
I hypothesize that Yellow Birch is limited by N in the old stands.
Conclusions Trends suggest Beech growth efficiency is limited by P, and Yellow Birch efficiency is limited by N Species specific traits may indicate co-limitation With the fertilizer treatments we are testing whether nutrient additions indicate co-limitation