Examinando por Autor "Roig, Fidel Alejandro"
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Ítem Climate variability of the southern Amazon inferred by a multi-proxy tree-ring approach using Cedrela fissilis Vell.(Elsevier, 2023-05-01) Ortega-Rodríguez, Daigard Ricardo; Sánchez-Salguero, Raúl; Hevia, Andrea; Granato-Souza, Daniela; Cintra, Bruno B.L.; Hornink, Bruna; Andreu-Hayles, Laia; Assis-Pereira, Gabriel; Roig, Fidel Alejandro; Tomazello-Filho, MarioThe analysis of climate variability and development of reconstructions based on tree-ring records in tropical forests have been increasing in recent decades. In the Amazon region, ring width and stable isotope long-term chronologies have been used for climatic studies, however little is known about the potential of wood traits such as density and chemical concentrations. In this study, we used well-dated rings of Cedrela fissilis Vell. from the drought-prone southern Amazon basin to assess the potential of using inter-annual variations of annually-resolved ring width, wood density, stable oxygen isotope (δ18OTR) measured in tree-ring cellulose and concentration of Sulfur (STR) and Calcium (CaTR) in xylem cells to study climate variability. During wet years, Cedrela fissilis produced wider and denser rings with higher CaTR and lower STR, as well as depleted δ18OTR values. During dry years, a wider range of responses was observed in growth, density and STR, while lower CaTR and enriched δ18OTR values were found. The annual centennial chronologies spanning from 1835 to 2018 showed good calibration skills for reconstructing local precipitation, evapotranspiration (P-PET), Amazon-wide rainfall, as well as climate modes related to sea surface temperature (SST) anomalies such as El Niño South Oscillation (ENSO), Tropical Northern Atlantic (TNA), and the Western Hemisphere Warm Pool (WHWP) oscillations. CaTR explained 42 % of the variance of local precipitation (1975–2018), RW explained 30 % of the P-PET variance (1975–2018), while δ18OTR explained 60 % and 57 % of the variance of Amazon rainfall (1960–2018) and El Niño 3.4 (1920–2018), respectively. Our results show that a multi-proxy tropical tree-ring approach can be used for high-reliable reconstructions of climate variability over Amazon basin at inter-annual and multidecadal time scales.Ítem Long- and short-term impacts of climate and dry-season on wood traits of Cedrela fissilis Vell. in southern Brazilian Amazon(Elsevier B.V., 2023-04-15) Ortega-Rodríguez, Daigard Ricardo; Sánchez-Salguero, Raúl; Hevia, Andrea; Granato-Souza, Daniela; Assis-Pereira, Gabriel; Roig, Fidel Alejandro; Tomazello-Filho, MarioDuring the last two decades the tropical Amazon forests have been impacted by frequent and severe droughts. However, little is known about the impacts of these extreme events on wood traits. In this study, we quantified long- and short-term impacts on growth and wood density response and resilience strategies under extreme droughts, analyzing the wood trait trends and correlations with climate variables (temperature, precipitation, and the SPEI drought index). Then, we simulated tree-ring formation and its responses to soil moisture using the process-based VS-Lite growth model. Our results showed how climate anomalies and dry spells increased since 1990s in the southern Amazon region and have affected the growth and wood density of C. fisillis. Ring width, latewood width and minimum wood density experienced the highest sensitivity to drought. C. fissilis showed wider (narrower) and more (less) dense rings during wetter (drier) years, respectively, suggesting that the species undergoes functional plasticity in the formation of its wood in order to adapt to dry conditions. Changes in water limitations during the dry season modify growth thresholds and long-term resilience, leading to decrease growth and increase wood density, enhancing the vulnerability of C. fissilis to projected climate warming scenarios. The short-term resilience is evidenced more in wood density than in the ring width, indicating the species’ ability to adapt to short drought periods. This study is a first attempt to evidence the characteristics of the annual growth rings of C. fissilis trees in relation to climate sensitivity and resilience to drought, based on long-term data from the seasonal moist tropical forest of the Amazon.