Oxygen isotopes in tree rings of Cedrela odorata L. as an indicator of hydroclimate variations in a seasonally dry tropical forest in northeastern Brazil

Pagotto MA, Nunes Menezes IR, Costa CM, Lisi CS, Bräuning A (2021)


Publication Type: Journal article

Publication year: 2021

Journal

DOI: 10.1007/s00468-021-02158-z

Abstract

In seasonally dry tropical environments, natural archives of isotopes present in cellulose of tree rings can be used to study changes in the hydrological cycle. We investigated the stable oxygen isotope ratios in tree-ring cellulose (delta O-18(TRC)) of Cedrela odorata L. from Caatinga forest, northeastern Brazil, and tested if delta O-18(TRC) is correlated to climate parameters. We extracted the alpha-cellulose from the most recent 50 tree rings (1968-2017). The inter-annual variation of delta O-18(TRC) was strongly synchronized (r = 0.65) among all five studied individuals and closely related to changes in humidity during the growing season. The delta O-18(TRC) was significantly correlated (p < 0.01) with precipitation (r = - 0.59), relative humidity (r = - 0.37), air temperature (r = 0.55), soil water deficit (r = 0.62) and PDSI drought index (r = - 0.62), with most significant correlation during wet season and in the first month of the dry season. The relationship with local climate variables reflects the effect of evaporative enrichment of leaf water on delta O-18(TRC), whereby dry soil conditions, the low relative humidity and high air temperature reduce stomatal conductance and lead to increased evaporative enrichment of delta O-18(TRC). Spatial correlations revealed a strong impact of PDSI in delta O-18(TRC). Our results also show an increase in delta O-18(TRC) values from the 1990s onwards due to extreme and recurring droughts in northeastern Brazil. We conclude that delta O-18(TRC) variations are related to the climatic conditions, especially during the wet period due to the greater water availability for plant physiological processes.

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APA:

Pagotto, M.A., Nunes Menezes, I.R., Costa, C.M., Lisi, C.S., & Bräuning, A. (2021). Oxygen isotopes in tree rings of Cedrela odorata L. as an indicator of hydroclimate variations in a seasonally dry tropical forest in northeastern Brazil. Trees-Structure and Function. https://dx.doi.org/10.1007/s00468-021-02158-z

MLA:

Pagotto, Mariana Alves, et al. "Oxygen isotopes in tree rings of Cedrela odorata L. as an indicator of hydroclimate variations in a seasonally dry tropical forest in northeastern Brazil." Trees-Structure and Function (2021).

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