Impacts and uncertainties of climate change projections on Eucalyptus plantations productivity across Brazil

Eucalyptus is the world's most planted hardwood tree. Concerns about potential impacts and uncertainties of climate change on Eucalyptus plantations productivity are arising and studies about that are still scarce. This study assesses the effects of climate change on Eucalyptus plantations productivity across a geographic gradient in Brazil by mid- and end-century and quantifies the uncertainty of climate and productivity projections. Ten global circulation models (GCM) under intermediate (RCP4.5) and high (RCP8.5) greenhouse gas emission scenarios, for the 2040-2069 and 2070-2099 periods were used for future climate projections. The APSIM Next Generation Eucalyptus model was used to simulate the Eucalyptus mean annual increment (MAI, m(3) ha(-1) yr(-1)) at seven years for eight locations in Brazil. The response of Eucalyptus productivity is expected to be site-specific and will mostly depend on the balance between the possible negative effects of increasing temperatures and the potential productivity increments caused by higher CO2 concentration. Plantations located in South and Southeast Brazil are expected to experience increases in MAI, while those located in Center-North Brazil will experience more pronounced MAI reductions. Uncertainties in projections are higher under RCP8.5 and for the end-of-century, especially for annual rainfall and MAI. Future climate projections from GCMs coupled with a Eucalyptus simulation model provide valuable information to facilitate the exploration of potential strategies and guidance of policy decision-making for forestry adaptation to climate change on a regional or national scale. However, forest companies and foresters should be cautious when using projected information for local-scale adaptation options, as the uncertainties in climate (especially in rainfall) and productivity projections are substantially large.