1. Surprising natural variation in nutrient availability and nutrient resorption Craig See SUNY-ESF Photo: USFS

2. Before the leaves fall... Nutrients move from leaves to stem tissues Resorption Efficiency = percent of leaf nutrients resorbed before abscission Is it a predictor of site nutrient status? Higher efficiency in nutrient poor sites (Flanagan and Van Cleve 1983, Boerner 1984) No effect (Chapin and Moilenan 1991, Schlesinger 1989) 45-63% less nitrogen 43-73% less phosphorus (Boerner 1984)

3. Resorption in the MELNHE stands In 2009, trees in mid and old stands resorbed more phosphorus relative to nitrogen than in the younger stands.

4. 2010 Methods Stands Sampled: Young: C1, C2 Mid: C4, C6, HB-mid, JB-Mid Old: C8, C9, HB-Old, JB-Old Fresh leaves sampled August, litter sampled in October Stand level resorption efficiency calculated as the mean of plot efficiencies. STILL PRETREATMENT

8. Root P Concentrations by Stand

11. 1 4 3 2

12. C8 ROOT P CONCENTRATIONS (0-10cm depth) 1 2 3

13. AVAILABLE SOIL P FROM RESIN STRIPS

14. CUMULATIVE P CONCENTRATION FOR AMMONIUM CHLORIDE + PEROXIDE + COLD NITRIC ACID LEACHES

15. FOLIAR CONCENTRATIONS

16. Conclusions Data suggests that site nutrient availability does affect nutrient resorption Many of the MELNHE stands (Not C8-3) may be phosphorus limited Nutrient limitation at what scale?

17. Thank You Ruth Yanai Melany Fisk Steven Hamburg Tim Fahey Matt Vadeboncoeur Doug Ryan Kikang Bae Shinjini Goswami Braulio Quintero Shoestring Crew

18. Aerts, R. 1996. Nutrient resorption from senescing leaves of perennials: Are there general patterns? Journal of ecology 84: 597-608 Boerner, R. 1984. Foliar nutrient dynamics and nutrient use efficiency of four deciduous tree species in relation to site fertility. Journal of Applied Ecology, 21: 1029-1040 Chapin, S., and L. Moilenan. 1991. Nutritional controls over nitrogen and phosphorus resorption from Alaskan birch leaves. Ecology 72: 709-715 Cote, B., J.W. Fyles, H. Djalilvand 2002. Increasing N and P resorption efficiency and proficiency in northern deciduous hardwoods with decreasing foliar N and P concentrations. Flanagan, P. W., and K. Van Cleve. 1983. Nutrient cycling in relation to decomposition and organic matter quality in taiga ecosystems. Canadian Journal of Forest Research 13: 795-817. Ryan, D.F., Bormann, FH. 1982. Nutrient resorption in northern hardwood forests. Bioscience 32: 29-32. Schlesinger, W. H., E. H. DeLucia, and W. D. Billings. 1989. Nutrient-use efficiency of woody plants on contrasting soils in the western Great Basin, Nevada. Ecology 70:105-113 REFERENCES