Caracterización química de la madera de híbridos interespecíficos entre Eucalyptus grandis y Eucalyptus dunnii

In Uruguay, Eucalyptus grandis and Eucalyptus dunnii are key species in pulp production. This study focused on the chemical characterization of wood from interspecific hybrids between these species to assess their suitability for pulp production. A total of 198 wood samples were collected from 29 families distributed across two trials, involving two cross types: E. dunnii x E. grandis and E. grandis x E. dunnii. Several chemical analyses were conducted to determine the content of extractives, calcium, ash, and moisture. Extractive content was measured using a Soxhlet apparatus with ethanol as the solvent, while calcium and ash content were determined through muffle furnace digestion at 500 °C. Descriptive analyses were performed for these variables, followed by the application of linear models to evaluate the effects of factors such as family, cross type, and trial on the chemical parameters. Tukey's tests were applied to compare means, and Pearson correlation analyses were conducted between these variables and wood quality traits, including pulp yield and basic density. Significant differences were found only between cross types for calcium and ash content. Rankings by family were created select the best families for these parameters, revealing that hybrids with E. dunnii as the maternal parent exhibited higher calcio and abs contents, while hybrids with E. grandis as the maternal parent showed lower levels. Although no significant effects were found for extractives, rankings by family were also performed. The data analysis suggested a potential relationship between cross type and extractive content, where E. dunnii x E. grandis hybrids tended to cluster around lower and intermediate levels, while E. grandis x E. dunnii hybrids showed a higher proportion of families with elevated levels. The correlation between pulp yield and extractive content was negative (-0,27). Conversely, the correlation between pulp yield and calcium content was 0,18, indicating a weak relationship.