reference : Centennial-scale reductions in nitrogen availability in temperate forests of the United States

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Bibliographic fields
reftype Journal Article
Abstract Forests cover 30% of the terrestrial Earth surface and are a major component of the global carbon (C) cycle. Humans have doubled the amount of global reactive nitrogen (N), increasing deposition of N onto forests worldwide. However, other global changes—especially climate change and elevated atmospheric carbon dioxide concentrations—are increasing demand for N, the element limiting primary productivity in temperate forests, which could be reducing N availability. To determine the long-term, integrated effects of global changes on forest N cycling, we measured stable N isotopes in wood, a proxy for N supply relative to demand, on large spatial and temporal scales across the continental U.S.A. Here, we show that forest N availability has generally declined across much of the U.S. since at least 1850 C.E. with cool, wet forests demonstrating the greatest declines. Across sites, recent trajectories of N availability were independent of recent atmospheric N deposition rates, implying a minor role for modern N deposition on the trajectory of N status of North American forests. Our results demonstrate that current trends of global changes are likely to be consistent with forest oligotrophication into the foreseeable future, further constraining forest C fixation and potentially storage.
Author McLauchlan, K. K.; Gerhart, L. M.; Battles, J. J.; Craine, J. M.; Elmore, A. J.; Higuera, P. E.; Mack, M. C.; McNeil, B. E.; Nelson, D. M.; Pederson, N.; Perakis, S. S.
DOI 10.1038/s41598-017-08170-z
Date 2017/08/10
ISSN 2045-2322
Issue 1
Journal Scientific Reports
Pages 7856
Title Centennial-scale reductions in nitrogen availability in temperate forests of the United States
Volume 7
Year 2017
Bibliographic identifiers
_record_number 21970
_uuid 4bcb66cd-68cb-488b-b043-2e612eb6a48e