Eucalyptus simulation models: understanding and mitigating the impacts of climate variability and change on forest productivity across Brazil

• Autor(a) principal: Elli, Elvis Felipe
• Data de Publicação: 2020
• Tipo de documento: Tese
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
• Texto Completo: https://www.teses.usp.br/teses/disponiveis/11/11152/tde-13082020-180005/
• topic: 3PG; 3PG; APSIM; APSIM; Déficit hídrico; Estresse por temperatura; FAO Agroecological Zone Model; Manejo sub-ótimo; Modelo da Zona Agroecológica - FAO; Sub-optimal management; Temperature stress; Water deficit

Eucalyptus plantations in Brazil face a large productivity variability, as a result of the effects of contrasting environmental conditions across the cultivated regions, genotype and management practices. Simulation models are important tools to guide forest planning and decision-making since they integrate biophysical aspects with climate, soil, management and genetic factors, predicting forest productivity. This study aimed to use different simulation models for assessing the effects of climate variability and change on Eucalyptus productivity across Brazil, and then to propose strategies for mitigating potential negative impacts on forest production. The models FAO, APSIM-growth, APSIM-Eucalyptus and 3PG were adapted, calibrated and evaluated using experimental yield data from 2012 to 2017 of eight Eucalyptus clones distributed over 23 locations in Brazil. After that, simulation models were applied to (i) determine the magnitudes and causes of Eucalyptus growth gaps in Brazil, (ii) gauge the effects of climate variability on Eucalyptus productivity; (iii) perform a global sensitivity analysis of various genetic traits under present and future climate scenarios and (iv) assess the susceptibility of Eucalyptus plantations to future climate scenarios and quantify the uncertainties in future projections. All assessed models performed well to predict Eucalyptus growth and yield across Brazil, and the use of an ensemble approach reduced the uncertainties in yield simulations when compared to the individual performance of the models. The water deficit was the main cause of Eucalyptus growth gaps in Central Northern Brazil, while in Southern Brazil, the sub-optimal forestry management was the main one. Spatial and temporal climate variability strongly affected Eucalyptus mean annual increment (MAI) across Brazil. Sites located in North Paraná and South São Paulo were the most productive ones. A higher MAI coefficient of variation was observed in drier environments. Traits for radiation use efficiency, leaf partitioning, fine root partitioning and extinction coefficient were the most influential for Eucalyptus yield under present climate. Traits for photosynthetic temperature response will become more important under future climates. The responses of Eucalyptus productivity to climate change will be highly site-specific and will mostly depend on the balance between the possible negative effects of climate stresses and the potential productivity increments by elevated CO2 concentration. In general, Eucalyptus plantations located in South and Southeast Brazil are expected to experience increases in attainable MAI under climate change scenarios, while those located in North Brazil will experience more pronounced MAI reductions. Future climate projections may provide valuable information that may facilitate the exploration of improved potential strategies for forestry adaptation on a regional or global scale. However, forest companies and foresters should be cautious when using projected information for local-scale adaptation options, since the uncertainties in future projections are substantially large. Eucalyptus simulation models performed well in simulating Eucalyptus productivity across a wide range of climates and soil types and for different Brazilian genotypes and, therefore, are promising tools forest planning and decision making, helping foresters and companies to assess mitigation strategies for increasing forestry resilience and productivity in the face of climate variability and change across Brazil.