Influence of environmental factors on the survival and growth of Eucalyptus tereticornis provenances in the Brazilian semi-arid

Climate variability poses a challenge to forestry in semi-arid regions, requiring the identification of resilient genotypes for sustainable cultivation. This study evaluated the survival, growth, and genetic traits of 16 provenances of Eucalyptus tereticornis under water and thermal stress over five years in Mossoró, Brazil. The experiment was conducted in a randomized block design with four replicates, each plot comprising five trees. Annual measurements were taken for diameter at breast height (DBH at 1.30 m), total height, wood volume, and survival rate. Additionally, soil and climatic data were analyzed to assess environmental influences on these traits. A mixed-model approach (REML/BLUP with LRT) was applied to estimate genetic parameters, while PCA explored trait relationships across provenances. The results demonstrated a strong interaction between provenances and environmental factors, with survival declining from 64 % in the third year to 7 % in the fifth year. The findings underscore the strong influence of environmental stressors, particularly elevated temperatures and reduced humidity, on survival and growth traits in Eucalyptus tereticornis. Some provenances, such as SSO EB18ZIM MT GARNET (P6) and Burdekin River (P12), exhibited resilience, maintaining survival rates above 25 %, whereas others, like Mill Stream Archer Creek (P10), showed high growth rates but low survival, highlighting a trade-off between productivity and stress tolerance. Genetic analyses indicated that heritability for growth traits was higher under favorable environmental conditions, whereas heritability for survival increased under environmental stress, particularly during the third year. These findings highlight the need for late-stage selection strategies that integrate adaptability and productivity, guiding breeding programs to enhance drought tolerance in climate-challenged forestry systems.