Riscos climáticos e vulnerabilidades de plantios florestais comerciais no brasil sob condições climáticas atuais e futuras

Abstract

The Brazilian forest sector is primarily supported by planted forests, which cover ~10.52 million hectares, account for more than USD 15.7 billion in exports, and generate ~ 2.8 million direct and indirect jobs. Traditionally, this commercial production has been dominated by exotic species such as Pinus spp., although there is growing interest in more profitable and high-value-added species, including teak (Tectona grandis L.f.), Brazilian mahogany (Swietenia macrophylla King), and African mahogany (Khaya spp.). Despite advances in forest management and silvicultural practices, the wood volume and quality of these species are likely to be impacted by climate conditions. To address these challenges, using climatic and bioclimatic risk indicators is an effective strategy for quantifying the vulnerabilities of Brazilian plantations under current and future climates. Although these indicators are essential tools for assessing magnitude, spatial distribution, typology, and severity levels, their application to Brazilian forest species of commercial interest remains limited. To fill this gap, this dissertation assesses the risks and vulnerabilities of commercial plantations of Pinus spp., T. grandis, S. macrophylla, and Khaya spp. in Brazil by developing and applying 36 specific indicators under current and future climate conditions. To achieve this aim, daily data of near-surface minimum (Tasmin, °C), mean (Tas, °C), and maximum (Tasmax, °C) air temperature, precipitation (P; mm day⁻¹), relative humidity (Hurs; %), and global solar radiation (Rsds; MJ m⁻² day⁻¹) were obtained from sixteen Global Climate Models (GCMs) from the NASA Earth Exchange Global Daily Downscaled Projection (NEX-GDDP-CMIP6). All risk indicators developed in this study were simulated for the baseline period (BP; 1995–2014) and projected for the near future (NF; 2041–2060) and far future (FF; 2081–2100) under two socioeconomic scenarios (SSP3-7.0 and SSP5-8.5). By the end of the 21st century, the greatest risks to Pinus plantations are associated with productivity losses (approximately 84% of the area under moderate to very high risk in the far future), followed by the wood wasp (Sirex noctilio) (17–87%), tip blight caused by Sphaeropsis sapinea (58–66%), stress related to basal temperatures (5–64%), needle blight caused by Calonectria pteridis (12–53%), and water deficit stress (32–45%). For T. grandis, the main risks are basal temperature stress (88–98%), productivity losses (84–88%), and canker incidence (53–59%). Lastly, S. macrophylla and Khaya spp. shown greater vulnerability to thermal stress, particularly at basal (48–89%) and maximum temperatures (41–80%). To mitigate productivity losses and minimize phytosanitary risks in these plantations, the adoption of effective and economically viable adaptation measures will be essential. These measures include selecting species and hybrids more tolerant to water and thermal stresses, implementing appropriate spacing and planting density management, performing thinning and pruning at appropriate intervals for each species, and strengthening control strategies for Sphaeropsis sapinea, Calonectria pteridis, Sirex noctilio, Hyblaea puera, and Hypsipyla robusta.