Uncertainties in the relationship between atmospheric nitrogen deposition and forest carbon sequestration

• Published in: Global change biology Vol. 14; no. 9; pp. 2057 - 2063
• Main Authors: SUTTON, MARK A., SIMPSON, DAVID, LEVY, PETER E., SMITH, ROGNVALD I., REIS, STEFAN, Van OIJEN, MARCEL, De VRIES, WIM
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.09.2008; Blackwell
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Atmospheric chemistry; atmospheric deposition models; biogeochemical models; Biological and medical sciences; Carbon sequestration; chronosequences; Climate change; covariance; data collection; europe; forest growth; forest stands; Forestry; Forests; Fundamental and applied biological sciences. Psychology; General aspects; General forest ecology; Generalities. Production, biomass. Quality of wood and forest products. General forest ecology; greenhouse gas budgets; latitude; net ecosystem production; net ecosystem productivity; Nitrogen; nitrogen deposition; regression analysis; uncertainty; Productivity; Forests; Atmospheric fallout; Growth; nitrogen deposition; Regression analysis; Atmospheric deposition; Nitrogen; net ecosystem productivity; uncertainty; Carbon sequestration; biogeochemical models; chronose- quences; atmospheric deposition models; Biogeochemistry; forest growth; Ecosystem; Greenhouse gas; greenhouse gas budgets; Air pollution; Models
• ISSN: 1354-1013; 1365-2486
• DOI: 10.1111/j.1365-2486.2008.01636.x

In a recent study, Magnani et al. report how atmospheric nitrogen deposition drives stand‐lifetime net ecosystem productivity (NEPav) for midlatitude forests, with an extremely high C to N response (725 kg C kg−1 wet‐deposited N for their European sites). We present here a re‐analysis of these data, which suggests a much smaller C : N response for total N inputs. Accounting for dry, as well as wet N deposition reduces the C : N response to 177 : 1. However, if covariance with intersite climatological differences is accounted for, the actual C : N response in this dataset may be <70 : 1. We then use a model analysis of 22 European forest stands to simulate the findings of Magnani et al. Multisite regression of simulated NEPav vs. total N deposition reproduces a high C : N response (149 : 1). However, once the effects of intersite climatological differences are accounted for, the value is again found to be much smaller, pointing to a real C : N response of about 50–75 : 1.