Climate change on Eucalyptus plantations and adaptive measures for sustainable forestry development across Brazil

Abstract

The main challenges facing the Eucalyptus plantation industry are employing sustainable projects in suitable areas, and using safer forestry strategies, given climate variability and climate change. Brazil is the world’s largest Eucalyptus producer, and more areas have been allocated for Eucalyptus plantations, even in areas that are considered persistent climate change hotspots. Researchers can combine adequate agroclimatic zoning methods with Earth System Model (ESMs) outputs to analyze changes to climate variables, to map suitable areas, and to outline adaptive measures for Eucalyptus plantations. Despite these facts, studies on the Eucalyptus species are still scarce. This study analyzed the impacts of climate change to suitable areas for planting Eucalyptus in Brazil, using proper Agroclimatic Zoning (AZ) method, and outlining effective adaptive measures for sustainable Eucalyptus cultivation under future climate scenarios. Daily precipitation, air temperature (mean and maximum), and global solar radiation data were used from a set of simulations and projections of nine ESMs, from the Coupled Model Intercomparison Project Phase 5 (CMIP5), in two Representative Concentration Pathway scenarios (RCP 4.5 and 8.5). The AZ method was simulated for the current climate (1980–2005), and projected for the near (2021–2050), and far future (2071–2100) climates, in two RCPs. Given intense and persistent changes to precipitation, air temperature, evapotranspiration, and water deficits, i.e., prolonged and continued changes to climate variables resulting from climate change, Eucalyptus plantations will be restricted and economically unfeasible for industrial purposes for about 15 % (RCP 4.5), to 47 % (RCP 8.5), of Brazil in the far future, covering a large part of the North, the north of the Center-West, and the northwestern part of the Northeast, including the new Brazilian agroforestry frontier (MATOPIBA). Only ∼12 % of Brazil, encompassing small areas of the South, the South-Southeast, and a small portion in the Northwest region of the North, will be suitable for Eucalyptus plantations, since these regions are less vulnerable to climate change. As for the rest of Brazil (between ∼42 % and ∼80 %), regular suitability is projected, and the future of Eucalyptus plantations in these places will depend on adopting ‘effective adaptive measures’ and making ‘safe silvicultural decisions’ in order to deal with projected temperature increases and water deficits, including genotypes selection, improvements in hybridization techniques or breeding programs, planting in wider spacings (or lower stockings), and thinning and pruning at shorter intervals.