Forest plantations with public subsidies: to harvest or not to harvest, this is the question

In the last three decades the European Union has supported the afforestation of lands previously devoted to agriculture through targeted subsidies, thus enhancing the provision of many ecosystem services (ESs). However, most of these plantations are close or even above the minimum permanence period and will be likely eradicated by landowners to restore the previous land use (i.e., croplands). In this scenario, the investments for carbon (C) sequestration will be nullified and the supply of many other ESs, which have developed along with plants growth, will be drastically reduced. In this commentary, using as reference a case study in the Friuli Venezia Giulia Autonomous Region (NE Italy), we quantify the value of wood production and C sequestration ESs of tree plantations, simulating a present and a future scenario. Our simulations show that by extending the permanence of these stands for 20 more years, a 34% increase of biomass annual Net Present Value will be expected on average, according to its final use. Regarding C sequestration, a total C stock of 167 tC ha-1 can be estimated in 40 years, corresponding to a cumulative Net Present Value of more than 11 million euro. Thus, if C sequestration is considered, the overall annual Net Present Value shows a 35% increase on average, when compared to a reconversion to corn. These data suggest the need for a new national and European strategy, which not only considers well-planned new afforestation campaigns, but also aims at maintaining at least part of the afforested lands, thus maximizing ESs and supporting high quality wood production. At the end of the rotation period, new cycles can be promoted on the same surfaces through natural gamic or agamic regeneration. An additional important aspect to consider is also related to the active management of these stands, thus to improve their growth (quantity and quality), in situ C storage as well as storage in final products.