Dendrocronologia na Floresta Atlântica de Tabuleiros: uma abordagem sobre a floresta e o clima

Abstract

This thesis aimed to contribute to the understanding of the influence of climate on the growth of tropical tree species. For that, a review of the dendrochronological researches with a climatic approach developed in the Atlantic Forest Biome was carried out, seeking to verify the evidenced climatic signs and the methods applied to the chronologies. The wood anatomy of Copaifera lucens was investigated with a focus on the anatomical characteristics of the growth-rings. It has also tested the influence of climate on its radial growth. The results of the literature review showed that few species are explored through dendrochronology (10 spp.), and there are no studies for the northern part of this biome. Climatic signals related to precipitation were observed in 87% of the chronologies and to temperature in 50% of them, although there is no synchronism between the periods of the influence of these variables in the species. The results of the wood anatomy added anatomical characteristics previously not described for C. lucens, such as gelatinous fibers, bifurcated fibers (intrusive growth) and cluster vessels. Although the wood anatomy contributes to the understanding of the wood structure, studies of cambial activity are showed to clarify the formation of the annual and intra-annual rings, and especially the formation of secretory canals. The results of the dendrochronological studies demonstrate that C. lucens, despite the high growth variation within and between individuals, is promising for climate reconstruction. Their series presented a strong positive correlation with the evapotranspiration index for the current summer. The climatic scenarios for the region of occurrence of the species show a reduction in precipitation, and it can be inferred that its growth in the future will be compromised. As a general conclusion, it was observed that the effects of climate in the Atlantic Forest are still little explored through dendrochronology. It is necessary to intensify dendroclimatic studies to clarify the climatic influences in the different phytophysiognomies of this biome. The anatomy of the Copaifera genus is complex and the factors that control the formation of the annual ring deserve more research efforts. Given the marked sensitivity of the ring width series to the water availability of summer and the considerable longevity of its trees, C. lucens has a high potential for dendroclimatic reconstructions in the northern region of the Brazilian Atlantic Forest.