Fluxo de carbono via serapilheira em florestas urbanas de São Paulo: compreensão do funcionamento da infraestrutura verde da cidade

Abstract

São Paulo is the most populous city in Brazil and goes through continuous demographic pressure. In it is the biome of the Atlantic Forest that suffers loss of habitat due to anthropic actions. The forests of the City of São Paulo present several benefits such as the reduction of heat islands, as well as the attenuation of atmospheric pollution and the regulation of biogeochemical cycles such as carbon and nitrogen. The objective of this research was to evaluate the production and decomposition of litter from two urban forests of São Paulo, SP: Parque Trianon Masp (PT) and Parque Alfredo Volpi (PAV). The analysis was carried out from the collection of litter that was given by means of collectors installed in 21 plots of each park, being carried out once a month. The collected material was dried, sorted in fractions of leaves, twigs, reproductive and miscellaneous parts, and weighed in analytical and crushed balance. The decomposition was performed from "litter bags" installed randomly near the collectors. Each month six bags were removed from each park, washed in running water, dried and weighed to obtain the remaining mass. Trianon Park produced a total of 3,185 kg ha-1 year-1, while Alfredo Volpi Park produced 3,014 kg ha-1 year-1. The month with the highest peak of production in both parks was in September, with a total of 533.66 kg in the PT and 466.69 kg in the PAV. The climatic conditions during the study, such as wind appear to show direct interference in these results and the litter decomposition rate followed exponential decay in both parks, showing a total of 270.11 days (PT) and 323.62 days (PAV) to decompose 50% of the exposed material and 1169.05 days (PT) and 1400.65 (PAV) to decompose 95% of the litter. The decomposition constant (k) was 0.002566183 g dia-1 (PT) and 0.002141868 g dia-1 (PAV). Microclimatic variables seem to have been important in the evaluated ecosystem processes, suggesting that the abundance of trees in urban parks may be important in existing patterns. These results bring, in the light of public management, the importance of rethinking the management of urban green areas and understanding the monitoring of the green infrastructure of the city of São Paulo.