Presentation on theme: "Surprising natural variation in nutrient availability and nutrient resorption Craig See SUNY-ESF Photo: USFS."— Presentation transcript:
Surprising natural variation in nutrient availability and nutrient resorption Craig See SUNY-ESF Photo: USFS
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)
Resorption in the MELNHE stands In 2009, trees in mid and old stands resorbed more phosphorus relative to nitrogen than in the younger stands.
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
Root P Concentrations by Stand
C8 ROOT P CONCENTRATIONS (0-10cm depth) 1 2 3
AVAILABLE SOIL P FROM RESIN STRIPS
CUMULATIVE P CONCENTRATION FOR AMMONIUM CHLORIDE + PEROXIDE + COLD NITRIC ACID LEACHES
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?
Thank You Ruth Yanai Melany Fisk Steven Hamburg Tim Fahey Matt Vadeboncoeur Doug Ryan Kikang Bae Shinjini Goswami Braulio Quintero Shoestring Crew
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