Effetti della deposizione atmosferica azotata su produttività e allocazione della crescita. Primi risultati di un esperimento di lungo termine in una faggeta appenninica [Effects of atmospheric nitrogen deposition on productivity and growth allocation. First results of a long-term experiment in a pre-alpine beech forest]

Atmospheric nitrogen deposition is an important global change driver, potentially affecting forest health and productivity. In order to evaluate the potential effects on tree growth and above-ground biomass production in southern European conditions, a long-term manipulation experiment was carried out in a prealpine beech forest (Pian Cansiglio, BL). Four treatments are compared: (i) control, (ii) moderate soil fertilization, (iii) high soil fertilization (iv) and moderate above canopy fertilization. Results, 7 years into the experiment, do not show any effect of soil fertilization treatments on the monitored parameters, but show instead positive effects of the canopy fertilization on the allocation of resources to the canopy and on the production of leaf biomass, with values that in 2021 exceeded those observed in the control treatment by 0.72 Mg DM ha-1. The contribution of N due to atmospheric deposition does not seem to decrease the growth of pre-alpine beech forests in the short term, but could substantially alter their ecological dynamics.