Abstract

Keywords

Nitrogen deposition;Europe;Nitrogen saturation;Leaf form;Temperature;Nitrogen sensitivity

Abstract

Raised emissions of biologically reactive nitrogen (N) have intensified N deposition, enhancing tree productivity globally. Nonetheless, the drivers of forest sensitivity to N deposition remain unknown. We used stem growth data from 62,000 trees across Europe combined with N deposition data to track the effects of air temperature and precipitation on tree growth's sensitivity to N deposition and how it varied depending on leaf form over the past 30 years. Overall, N deposition enhanced conifer growth (until 30 kg N ha-1 yr-1) while decreasing growth for broadleaved angiosperms. Lower temperatures led to higher growth sensitivity to N deposition in conifers potentially exacerbated by N limitation. In contrast, higher temperatures stimulated growth sensitivity to N deposition for broadleaves. Higher precipitation equally increased N deposition sensitivity in all leaf forms. We conclude that air temperature and leaf form are decisive in disentangling the effect of N deposition in European forests, which provides crucial information to better predict the contribution of N deposition to land carbon sink enhancement.

LWF Classification

Network: LWF;growth, Sites: Alptal;Beatenberg;Bettlachstock;Celerina;Chironico;Davos;Isone;Jussy;Lägeren;Lausanne;Lens;Nationalpark;Neunkirch;Novaggio;Othmarsingen;Schänis;Visp;Vordemwald, Category: ISI,