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Supplementary Materials:

Table S.1. Parameters Used in Current Version of the TRACE Model for Study Site Characteristics, Vegetation Properties, and Soil Properties with the Units and the Source for Each Parameter and the Ecosystem Type from which Each Parameter Value was Obtained

Parameter Description / Units / Ecosystem / Source
Study Site Characteristics
Latitude / degrees / Study Sites / Burton and others 2004
Longitude / degrees / Study Sites / Burton and others 2004
Elevation / m / Study Sites / Burton and others 1996
Overstory Age / years / Study Sites / Burton and others 2004
Vegetation
Specific Leaf Weight / g m-2 / Study Sites / Pregitzer and others 2008, and Burton and others 1991
Maximum Foliar Mass in Canopy / g OM / m2 / Study Sites
Fraction of N in Foliage Resorbed in Senescence / Study Sites / Pregitzer and others 2010
N concentration in foliar litter / g N / g OM / Study Sites / Zak and others 2008
Acid Insoluble Fraction of Foliar Litter / g C / g OM / Sugar Maple / Currie and others 2010
Acid Soluble Fraction of Foliar Litter / g C / g OM / Sugar Maple / Currie and others 2010
Total Extractives Fraction Foliar Litter / g C / g OM / Sugar Maple / Currie and others 2010
Parameter Description / Units / Ecosystem / Source
Vegetation
Acid Soluble Fraction of Fine Root Litter / g C / g OM / Sugar Maple / Hendricks and others 2000
Standing Branch Wood Mass / g OM / m2 / Study Sites / Zak and others 2008
Standing Stem (Wood and Bark) Mass / g OM / m2 / Study Sites / Zak and others 2008
Coarse (Woody) Root Mass / g OM / m2 / Study Sites / Zak and others 2008
Fine Root (< 1.0 mm) Mass / g OM / m2 / Study Sites / Zak and others 2008
Fraction of Fine Roots in the Organic Horizon / Study Sites / Hendrick and Pregitzer 1996
N Concentration in Living Fine Roots / g N / g OM / Study Sites / Zak and others 2008
Acid Insoluble Fraction of Fine Root Litter / g C / g OM / Sugar Maple / Hendricks and others 2000
Total Extractives Fraction of Fine Root Litter / g C / g OM / Sugar Maple / Hendricks and others 2000
Soil
Decay Rate of Humus / Derives from Model Calibrations
Ratio of Decay Rate of Mineral LSOM to Humus / Derives from Model Calibrations
N Fixation Rate in Woody Debris / Roskoski 1980
Parameter Description / Units / Ecosystem / Source
Soil
Mass of Fine Woody Debris (<10 cm Diameter) / g OM / m2 / Mixed Hardwoods / Estimated after Gough and others 2007
Mass of Fine Woody Debris (>10 cm Diameter) / g OM / m2 / Mixed Hardwoods
N Pool in Fine Woody Debris (<10 cm Diameter) / g N / m2 / Mixed Hardwoods / Estimated with C:N ratio of 95
N Pool in Fine Woody Debris (>10 cm Diameter) / g N / m2 / Mixed Hardwoods / Estimated with C:N ratio of 93
Mass of Acid Insoluble Carbon in Litter and Oe Layer / g OM / m2 / Sugar Maple / Using mass of O horizon (assuming half is humus) and litter fractions (foliar vs. fine roots) from Zak and others (2008), C:N ratios from Lovett and others (2004), litter C fractions from Currie and others 2010 and Hendricks and others 2000.
Mass of Acid Soluble Carbon in Litter and Oe Layer / g OM / m2 / Sugar Maple
Mass of Total Extractives in Litter and Oe Layer / g OM / m2 / Sugar Maple
N Pool within Acid Insolubles in Litter and Oe Layer / g N / m2 / Sugar Maple
N Pool within Acid Solubles in Litter and Oe Layer / g N / m2 / Sugar Maple
N Pool within Total Extractives in Litter and Oe Layer / g N / m2 / Sugar Maple
Mass of Humified Material in the Organic Horizon / g OM / m2 / Sugar Maple
N Pool in Organic Horizon Humified Material / g N / m2 / Sugar Maple
Mass of Mineral Soil Organic Matter / g OM / m2 / Study Sites / Zak and others 2008
Parameter Description / Units / Ecosystem / Source
Soil
Pool Size of Available Nitrate in the Organic Horizon / g N / m2 / Study Sites / Zak and others 2004
Pool Size of Available Ammonia in the Organic Horizon / g N / m2 / Study Sites / Zak and others 2004
N Pool Size in Mineral Soil Organic Matter / g N / m2 / Study Sites / Zak and others 2008
Mass of Nonwoody Litter Buried in Mineral Soil / g OM / m2 / Sugar Maple / Estimated after Gough and others 2007
N Pool Size in Nonwoody Litter Buried in Mineral Soil / g N / m2 / Sugar Maple
Mass of Fine Woody Debris Buried in Mineral Soil / g OM / m2 / Mixed Hardwoods
N Pool Size in Fine Woody Debris Buried in Mineral Soil / g N / m2 / Mixed Hardwoods / Estimated with C:N ratio of 85
Pool Size of Available Nitrate in the Mineral Soil / g N / m2 / Study Sites / Zak and others 2008
Pool Size of Available Ammonia in the Mineral Soil / g N / m2 / Study Sites / Zak and others 2008
Ratio of Gross Nitrification: Gross N Mineralization in the Mineral Soil / Study Sites / Zak and others 2006


Table S.2. : Data Sources and Study Characteristics for the Leaf Litter Decomposition Experiments Used to Calculate Changes in Decomposition Rate and Extent for TRACE Model Modifications to create the “Rate Model”, “Extent Model”, and “Rate and Extent Model” in the Present Analysis

Source / Incubation Length / Litter Species / Location / Litter LCI / N Addition
Magill and Aber 1998 / 72 months / Red Pine (Pinus resinosa) / Harvard Forest Pine Plots / 0.40 / 5 g/m2
15 g/m2
Harvard Forest Oak Plots / 0.40 / 5 g/m2
15 g/m2
Red Maple (Acer rubrum) / Harvard Forest Pine Plots / 0.32 / 5 g/m2
15 g/m2
Harvard Forest Oak Plots / 0.32 / 5 g/m2
15 g/m2
Yellow Birch (Betula lenta) / Harvard Forest Pine Plots / 0.29 / 5 g/m2
15 g/m2
Black Oak (Quercus velutina) / Harvard Forest Oak Plots / 0.39 / 5 g/m2
15 g/m2
Source / Incubation Length / Litter Species / Location / Litter LCI / Nitrogen Addition
Prescott 1995 / 36 months / Lodgepole Pine (Pinus contorta) / Mont Tremblant, Canada / 11.2 g/m2
Hobbie and Vitousek 2000 / 24 months / Metrosideros polymorpha / Hawaii (Thurston Flow) / 0.38 / 10 g/m2
Hawaii (Kauai Flow) / 0.39 / 10 g/m2
Hobbie 2000 / 30 months / Metrosideros polymorpha / Hawaii (1859 Flow) / 0.31 / 10 g/m2
Hawaii (High Elevation Flow) / 0.30 / 10 g/m2
Hawaii (Kaniku Flow) / 0.27 / 10 g/m2
Hawaii (1855 Flow) / 0.42 / 10 g/m2
Hawaii (Thurston Flow) / 0.43 / 10 g/m2
Prescott and others 1999 / 48 months / Trembling Aspen (Populus tremuloides) / Chetwynd, B.C. / 0.31 / 20 g/m2
Thirukkumaran and Parkinson 2000 / 4 months / Lodgepole Pine (Pinus contorta) / Kananaskis Valley, Canada / 0.31 / 18.8 g/m2
0.31 / 30 g/m2

LCI: litter lignocellulose index (Aber and others 1990).