Nitrogen isotopes in trees show declining fertility in US forests

Published by Christina Schaedel on

norma rivera core from aspen tree in alaska

Nitrogen isotopes in tree rings record the history of the nitrogen cycle—the critical nutrient that limits growth in many US forests.  ECOSS faculty member Michelle Mack, along with colleagues from seven other institutions, recently published a paper that shows nitrogen availability in US forests declining over the past century, with cool, wet forests demonstrating the greatest declines. The paper is open access and can be accessed here: www.nature.com/articles/s41598-017-08170-z.

NAU Biology major Norma Rivera takes a core from an aspen tree in Alaska. Photo credit: Samantha Miller.

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