| Dendrochronology in the Neotropical ombrophilous woodlands of Argentina: Sex-related, growth-climate association of Araucaria angustifolia |
| Paper ID : 1043-ADA2013 |
| Authors: |
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Nicolás Cattaneo1, Hugo Fassola2, Norberto Pahr3, Jorge Leporati4, Stella Marys Bogino *5 1State University of San Luis,
Argentina 2State Institute of Agricultural engineering 3State Institute of Agricultural Engineering 4State University of San Luis, Argentina 5Avenida 25 de Mayo 384 |
| Abstract: |
| Araucaria, pino Paraná or curý (Araucaria angustifolia (Bertol.) Kuntze) is a dioecious tree that dominates the mixed neotropical ombrophilous forests in Brazil and Argentina, South America, known as araucaria forests. The species is nowadays critically endangered by deforestation and global climate change. The goal of this study was to analyse the dynamics of radial growth in this species and its association with climatic variables, according to the sex, at its western range boundary in Argentina. Standard dendrochronological techniques were applied on stem disks from female and male trees. An analysis of variance (ANOVA) was performed to detect differences in mean radial growth between sexes. Chronologies were divided in 10-year periods (decade) to detect differences between sexes over time. Tree-ring widths were transformed using natural logarithms to assess the normality and the homogeneous variability of variance. The DENDROCLIM2002 program was used to analyse the dependence of residual chronologies of female and male trees on climate variables. 24 female and 21 male trees, out of the 60 trees initially sampled, were accurately cross-dated and then retained for subsequent analyses. Xylem anatomical anomalies, such as false rings, lenses, narrow rings, wedging rings, and missing rings made the tree-ring dating process difficult. Female and male trees showed growth patterns that changed over time, not being significant in the 1950-1990 period and highly significant from the 1990s onwards (p<0.1) when female trees had a higher growth rate. Female and male trees showed a different association with climatic variables. No significant effect of temperature and precipitation was identified on female trees. For male trees, rainfall had a positive effect in August, before the growing season, and a negative effect at the end of the growing season (March). Temperature had a negative effect on male trees, before and during the growing season (February and January, respectively). No effect of SOI was detected on both sexes. Results emphasised the usefulness of A. angustifolia for dendrochronological studies and the value of dioecious species for the study of sex-related growth-climate association. |
| Keywords: |
| araucaria, SOI, dioecious, dendroclimatology |
| Status : Abstract Accepted |
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