1. 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: goswams@muohio.edu

2. 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????

3. 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

4. Species composition in MELNHE stands

5. Foliar N:P by species in mid and old stands (different nutrient status) Green- mid Red- old No specific pattern

7. I hypothesize that Beech is limited by P in the old stands.

8. I hypothesize that Yellow Birch is limited by N in the old stands.

9. 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