, Volume 80, Issue 2, pp 143–171

Regional Assessment of N Saturation using Foliar and Root \(\varvec {\delta}^{\bf 15}{\bf N}\)


    • Northeastern Research StationUSDA Forest Service
  • P. H. Templer
    • Department of BiologyBoston University
  • C. L. Goodale
    • Department of Ecology & Evolutionary BiologyCornell University
  • S. Duke
    • Agricultural Research Service
  • P. M. Groffman
    • Institute of Ecosystem Studies
  • M. B. Adams
    • USDA Forest Service
  • P. Boeckx
    • University of Ghent
  • J. Boggs
    • USDA Forest Service
  • J. Campbell
    • USDA Forest Service
  • B. Colman
    • University of California
  • J. Compton
    • US Environmental Protection Agency
  • B. Emmett
    • Centre for Ecology and Hydrology
  • P. Gundersen
    • Danish Centre for Forest, Landscape and Planning
  • J. Kjønaas
    • Norwegian Forest Research Institute
  • G. Lovett
    • Institute of Ecosystem Studies
  • M. Mack
    • University of Florida
  • A. Magill
    • University of New Hampshire
  • M. Mbila
    • Alabama A&M University
  • M. J. Mitchell
    • SUNY School of Environmental Science and Forestry
  • G. McGee
    • SUNY School of Environmental Science and Forestry
  • S. McNulty
    • USDA Forest Service
  • K. Nadelhoffer
    • The University of Michigan
  • S. Ollinger
    • University of New Hampshire
  • D. Ross
    • University of Vermont
  • H. Rueth
    • Grand Valley State University
  • L. Rustad
    • USDA Forest Service
  • P. Schaberg
    • Northeastern Research StationUSDA Forest Service
  • S. Schiff
    • University of Waterloo
  • P. Schleppi
    • Swiss Federal Institute for Forest, Snow and Landscape Research
  • J. Spoelstra
    • University of Waterloo
  • W. Wessel
    • University of Amsterdam

DOI: 10.1007/s10533-006-9015-9

Cite this article as:
Pardo, L.H., Templer, P.H., Goodale, C.L. et al. Biogeochemistry (2006) 80: 143. doi:10.1007/s10533-006-9015-9


N saturation induced by atmospheric N deposition can have serious consequences for forest health in many regions. In order to evaluate whether foliar \(\delta^{15}\hbox{N}\) may be a robust, regional-scale measure of the onset of N saturation in forest ecosystems, we assembled a large dataset on atmospheric N deposition, foliar and root \(\delta^{15}\hbox{N}\) and N concentration, soil C:N, mineralization and nitrification. The dataset included sites in northeastern North America, Colorado, Alaska, southern Chile and Europe. Local drivers of N cycling (net nitrification and mineralization, and forest floor and soil C:N) were more closely coupled with foliar \(\delta^{15}\hbox{N}\) than the regional driver of N deposition. Foliar \(\delta^{15}\hbox{N}\) increased non-linearly with nitrification:mineralization ratio and decreased with forest floor C:N. Foliar \(\delta^{15}\hbox{N}\) was more strongly related to nitrification rates than was foliar N concentration, but concentration was more strongly correlated with N deposition. Root \(\delta^{15}\hbox{N}\) was more tightly coupled to forest floor properties than was foliar \(\delta^{15}\hbox{N}\). We observed a pattern of decreasing foliar \(\delta^{15}\hbox{N}\) values across the following species: American beech>yellow birch>sugar maple. Other factors that affected foliar \(\delta^{15}\hbox{N}\) included species composition and climate. Relationships between foliar \(\delta^{15}\hbox{N}\) and soil variables were stronger when analyzed on a species by species basis than when many species were lumped. European sites showed distinct patterns of lower foliar \(\delta^{15}\hbox{N}\), due to the importance of ammonium deposition in this region. Our results suggest that examining \(\delta^{15}\hbox{N}\) values of foliage may improve understanding of how forests respond to the cascading effects of N deposition.


15N Fine roots Forests N deposition Natural abundance

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© Springer 2006