Carbon stock in the biomass of native urban fragments: A case study in an Atlantic Forest remnant in Brazil

Aim of study: In the face of global concern about climate change, urban forests have great potential in the scenario of mitigating climate change and reducing emissions by carbon dioxide. Thus, the objective of this work was to evaluate the potential for carbon and carbon dioxide (CO2) removal of a forest fragment. Area of study: A native urban Atlantic Forest fragment located in Curitiba, State of Paraná, Brazil. Material and methods: To do so, dendrometric data measured in the years 2006, 2009, 2012, 2015, 2018 and 2021 were used, totalling 77,016 individuals. From these data, the height, shoot and underground biomass were estimated based on allometric equations available in the literature. The growth dynamics and carbon stock were quantified by the difference in carbon stock at the beginning (2006) and at the end of the assessment (2021) in general, by genus and by diameter class. Main results: The results showed that around 156.56 t.ha-1 of biomass were accumulated in 15 years, resulting in 64.23 t.ha-1 of carbon, 235.51 t.ha-1 of carbon dioxide equivalent (CO2eq) and annual removal of 4.06 t.ha-1.year-1. The genus Araucaria was predominant throughout the period in relation to the genera found, followed by Ocotea, Luehea and Casearia, while Gymmanthes, Clethra and Citronella were later included in the evaluations. Araucaria individuals with a diameter class of 60 and 70 cm were responsible for the largest amount of carbon stored. The carbon stock concentration for the other genera was higher for diameter classes smaller than 40 cm. Research highlights: Given the numbers found of annual carbon removal and biomass accumulation, it can be concluded that this native urban fragment positively contributed to the absorption and fixation of atmospheric carbon in forest biomass.