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Altered plant carbon partitioning enhanced forest ecosystem carbon storage after 25 years of nitrogen additions
Author(s) -
Eastman Brooke A.,
Adams Mary B.,
Brzostek Edward R.,
Burnham Mark B.,
Carrara Joseph E.,
Kelly Charlene,
McNeil Brenden E.,
Walter Christopher A.,
Peterjohn William T.
Publication year - 2021
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.17256
Subject(s) - environmental science , carbon sequestration , ecosystem , sink (geography) , biogeochemistry , biomass (ecology) , carbon sink , agronomy , biomass partitioning , soil carbon , nitrogen , watershed , litter , plant litter , vegetation (pathology) , human fertilization , forest ecology , ecology , soil water , biology , soil science , chemistry , carbon dioxide , geography , cartography , organic chemistry , pathology , machine learning , computer science , medicine
Summary Decades of atmospheric nitrogen (N) deposition in the northeastern USA have enhanced this globally important forest carbon (C) sink by relieving N limitation. While many N fertilization experiments found increased forest C storage, the mechanisms driving this response at the ecosystem scale remain uncertain. Following the optimal allocation theory, augmented N availability may reduce belowground C investment by trees to roots and soil symbionts. To test this prediction and its implications on soil biogeochemistry, we constructed C and N budgets for a long‐term, whole‐watershed N fertilization study at the Fernow Experimental Forest, WV, USA. Nitrogen fertilization increased C storage by shifting C partitioning away from belowground components and towards aboveground woody biomass production. Fertilization also reduced the C cost of N acquisition, allowing for greater C sequestration in vegetation. Despite equal fine litter inputs, the C and N stocks and C : N ratio of the upper mineral soil were greater in the fertilized watershed, likely due to reduced decomposition of plant litter. By combining aboveground and belowground data at the watershed scale, this study demonstrates how plant C allocation responses to N additions may result in greater C storage in both vegetation and soil.