N supply mediates the radiative balance of N2O emissions and CO2 sequestration driven by N‐fixing vs. non‐fixing trees. Issue 8 (9th July 2021)

• Record Type: Journal Article
• Authors: Kou‐Giesbrecht, Sian; Funk, Jennifer L.; Perakis, Steven S.; Wolf, Amelia A.; Menge, Duncan N. L.
• Is Part Of: Ecology. Volume 102:Issue 8(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-07-09
• Subjects: carbon dioxide -- nitrogen cycling -- nitrogen‐fixing trees -- nitrous oxide; Ecology -- Periodicals; Ecology -- Periodicals; Écologie -- Périodiques; Ecologie; Écologie; Écologie animale; Écologie végétale; Ecology; Periodicals; 577.05
• DOI: 10.1002/ecy.3414
• Languages: English
• ISSNs: 0012-9658

Abstract

Abstract: Forests are a significant CO2 sink. However, CO2 sequestration in forests is radiatively offset by emissions of nitrous oxide (N2 O), a potent greenhouse gas, from forest soils. Reforestation, an important strategy for mitigating climate change, has focused on maximizing CO2 sequestration in plant biomass without integrating N2 O emissions from soils. Although nitrogen (N)‐fixing trees are often recommended for reforestation because of their rapid growth on N‐poor soil, they can stimulate significant N2 O emissions from soils. Here, we first used a field experiment to show that a N‐fixing tree ( Robinia pseudoacacia ) initially mitigated climate change more than a non‐fixing tree ( Betula nigra ). We then used our field data to parameterize a theoretical model to investigate these effects over time. Under lower N supply, N‐fixers continued to mitigate climate change more than non‐fixers by overcoming N limitation of plant growth. However, under higher N supply, N‐fixers ultimately mitigated climate change less than non‐fixers by enriching soil N and stimulating N2 O emissions from soils. These results have implications for reforestation, suggesting that N‐fixing trees are more effective at mitigating climate change at lower N supply, whereas non‐fixing trees are more effective at mitigating climate change at higher N supply.