The metropolitan parks of Quito as important carbon sinks

Despite the importance of urban forests as important carbon sinks, studies in Ecuador have yet to assess their potential to store carbon. We assessed the carbon stored in the aboveground biomass (AGB) and annual rates of AGB accumulation in the Guanguiltagua Metropolitan Park (GMP) and the Southern Metropolitan Park (SMP). We installed 11 plots per park of 0.063 ha, where we surveyed all stems with a diameter at breast height (DBH) ≥2.5 cm. To estimate annual increments in AGB, we installed dendrometer bands on 10% of the total stems recorded in each plot (only in stems with ≥10 cm DBH). We measured the dendrometer band segment increase every 4 months from September 2019 to October 2020. Our results show that the GMP stores 171 ± 96 Mg C ha⁻¹, significantly higher than the amount of carbon storage recorded in the SMP (100 ± 41 Mg C ha⁻¹). In contrast, the GMP sequestered 3.30 ± 1.71 Mg C ha year⁻¹, while the SMP sequestered an average of 4.45 ± 2.63 Mg C ha year⁻¹. At the landscape scale, the SMP contains 0.072 Tg C (0.058–0.091, 95% CI), while the GMP contains a reservoir of 0.096 Tg C (0.067–0.13, 95% CI). Likewise, the AGB in the SMP 3,165 Mg C year⁻¹ (2209–4297, 95% CI), while that in the GMP sequestered 1859 Mg year⁻¹ (1361–2430, 95% CI). Our results show that the metropolitan parks of Quito are important carbon sinks and constitute essential elements in mitigating climate change in urban spaces.