Regional variation in foliar chemistry and N cycling among forests of diverse history and composition

  • Ollinger S
  • Smith M
  • Martin M
 et al. 
  • 184


    Mendeley users who have this article in their library.
  • 221


    Citations of this article.


Although understanding of nitrogen cycling and nitrification in forest eco- systems has improved greatly over the past several decades, our ability to characterize spatial patterns is still quite limited. A number of studies have shown linkages between canopy chemistry and N cycling, but few have considered the degree to which these trends can provide an indicator of forest N status across large, heterogeneous landscapes. In this study, we examined relationships among canopy chemistry, nitrogen cycling, and soil carbon: nitrogen ratios across 30 forested stands in the White Mountains of New Hampshire. Plots included a range of species (sugar maple, red maple, American beech, yellow birch, paper birch, red spruce, balsam fir, eastern hemlock) and were broadly grouped into two distur- bance categories: those that were historically affected by intensive logging and/or fire and those that experienced minimal human disturbance. Across all plots, rates of net N mineralization and net nitrification were correlated with canopy nitrogen concentrations, but the relationships differed between disturbance treat- ments. In deciduous forests, historically undisturbed stands had significantly higher rates of net N mineralization and net nitrification than previously disturbed stands, but these differences were not clearly reflected in patterns of stand-level canopy chemistry. Although soil C:N ratios also differed between disturbed and undisturbed stands, a relationship be- tween soil C:N ratios and canopy lignin:N ratios did not vary with either forest type or disturbance, suggesting that this trend is more consistent across diverse conditions. Relationships between foliar chemistry and N cycling within individual species revealed interesting differences between species and functional groups. For four out of five deciduous species, foliar N increased with increasing net N mineralization, indicating that species were responsive to changes in N availability and suggesting a positive feedback between foliar chemistry and soil N status. These patterns led to significant differences in foliar N between disturbance treatments for some species, but at the stand level, these differences were masked by successional changes in species composition. Among coniferous species, foliar N showed no variation across wide N-cycling gradients, suggesting a fundamentally different plant-soil interaction. We also examined the potential for extending observed field relationships to the regional U level using a high-quality data set of high spectral resolution remote sensing, obtained from NASA's AVIRIS instrument (Airborne Visible and InfraRed Imaging Spectrometer). Cloud- free AVIRIS data from 56 scenes covering the White Mountain National Forest were calibrated to canopy lignin:N ratios and were applied to prediction of C:N ratios in soils. Validation at 10 independent plots showed good prediction accuracy but suggested some overprediction at the low end of the range. Preliminary regional estimates of soil C:N ratios indicate that 63% of the region's land area falls below a value of 22. This value is significant because our field data identified this as a critical threshold for the onset of nitrification. Below C:N = 22, we expect increasing but variable rates of nitrification, depending on other factors such as disturbance or species composition.

Author-supplied keywords

  • C:N ratio
  • Canopy chemistry
  • Disturbance
  • Foliar nitrogen
  • Land use history
  • Nitrification
  • Nitrogen mineralization
  • Plant-soil relations
  • Regional variation
  • Remote sensing
  • Succession
  • White Mountains, New Hampshire (USA)

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document


  • Richard HallettUSDA Forest Service Northern Research Station

  • S. V. Ollinger

  • M. L. Smith

  • M. E. Martin

  • C. L. Goodale

  • J. D. Aber

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free