Gentilesca T, Ripullone F, Guerrieri Mr, Nolè A, Borghetti M
Contatto: Tiziana Gentilesca (email@example.com)
Abstract: In the last decades anthropogenic activities have strongly contributed to increase concentration of reactive nitrogen compounds in the atmosphere and their deposition (Ndep) back to the biosphere. Recent studies (Magnani et al. 2007) show a relevant and positive effect of Ndep on growth and carbon sequestration of temperate and boreal forests. Whilst still unexplored is the issue on the likely effects of Ndep on water-use efficiency (WUE, the ratio of CO2 assimilation on water transpired), that is an important parameter of forest productivity. Previous long-term N manipulation experiments at stand level show quite contrasting results. Our research aimed to investigate whether the higher N availability by Ndep for forests at global scale may have affected the WUE. To this aim we screened for a meta-analysis more than 30 published studies comprising about 50 sites of different forest ecosystem types around the world. Stable carbon isotope (ï¤13C) chronologies in tree rings, longest than fifty year, have been extracted and ï¤13C values have been used to calculate the intrinsic WUE (iWUE) according to equation of Farquhar et al. (1989). The iWUE mean values were then plotted for each site against the total atmospheric Ndep for year 1993, derived from the TM3 atmospheric transport model (Dentener 2006) with a spatial resolution of 5×3.75 deg. The results of this interesting global issue will be discussed in this poster to understand if forest ecosystems may have benefited from this additional N input.
Citazione: Gentilesca T, Ripullone F, Guerrieri Mr, Nolè A, Borghetti M (2009). Does the anthropogenic nitrogen deposition influence intrinsic water-use efficiency in forest ecosystems? A meta-analisys . 7° Congresso Nazionale SISEF, Isernia – Pesche (IS), 29 Set – 03 Ott 2009, Contributo no. #c7.7.55