Dendroclimatologia de Cedrela fissilis, no semiárido Mineiro

Abstract

Our understanding of the effects of climate change on the growth dynamics of tree species in tropical forests remains incomplete, particularly in regions with marked seasonal climate patterns. The aim of this study was to identify growth patterns over time, detect signs of extreme weather events in tree-ring chronologies, and assess the influence of climate change on the radial growth of the species. The study was conducted in the ecotone between the Cerrado and Caatinga biomes, in the semi-arid region of Minas Gerais, in the municipality of Januária (Peruaçu Caves National Park), where 40 trees of the species Cedrela fissilis were sampled, which were subsequently taken to the Dendrochronology Laboratory at UFLA, where laboratory procedures were carried out to obtain information relevant to the study. Using the COFECHA software and the ARSTAN program, the quality of the dendrochronological series dating and the establishment of chronologies were assessed, respectively. Finally, the analysis and processing of spatial and dendrometric data were carried out using R software (v. 4.5.2) within the RStudio environment. Subsequently, climatic and hydrological data (temperature, precipitation, river flow and drought indices over time) were used, obtained from official sources and stations closest to the sampling areas, such as WorldClim, ANA, INMET and CRU. Principal component regression was applied to reconstruct past climate, calibrating the treering data against seasonal climate observations. The results of this study demonstrate a strong correlation between the tree-ring series (0.719), and when correlated with average monthly precipitation, showed a moderate positive correlation (r ≈ 0.3–0.4), and a negative correlation with average annual temperature (r ≈ –0.26). The results suggest that the secondary growth of the tree species Cedrela fissilis responds to interannual climatic variations at a regional level. These results demonstrate the importance of incorporating dendroclimatic studies in order to obtain insights into the current state of forests in the face of climate change, and the responses of tree species in the study region to environmental stimuli within these ecosystems.