Avaliação das emissões de gases de efeito estufa a partir de queimadas florestais nos ecossistemas de Mopane e Miombo na província de Manica

Abstract

Forest fires are one of the environmental, economic and social problems in Mozambique. In addition to the possible effect on the change in the structure and composition of the forest ecosystem, forest fires are responsible for the emission of greenhouse gases (GHG) that are responsible for climate change. The present study was carried out in the province of Manica with the main objective of estimating GHG emissions and changes in biomass and carbon in forests due to forest fires. For this purpose, three districts were selected, namely: Tambara, Gondola and Manica belonging to the Mopane and Miombo ecosystems respectively. Two areas of 1 ha were allocated, one for control and the other for controlled burning. In each area, 9 plots of 20x20m were established to collect DAP data (cm) of tree species. Within the 20x20m plots, 1x1m subplots were established to collect samples of herbaceous and litter plants. The emissions resulting from the burning were determined using the indirect method, which consisted of using the IPCC equation, which proposes the measurement of forest biomass before and after the burning, and the direct method consisted of using an Analyzer CO 2 model 906 device. The results show that all the combustible material was semi-hazardous distributed vertically and horizontally and the moisture content was above 20%. During the fires, around 0.32 ton / ha and 0.16 ton / ha of biomass and carbon were consumed in the district of Gondola and 0.70 ton / ha of biomass and 0.35 ton / ha of carbon were lost to the district of Manica. Also 0.69 ton / ha and 0.345 carbon were lost respectively. Regarding greenhouse gas emissions, through the indirect method, approximately 0.51, 0.002, 0.0006 tons of CO 2, CH 4, N 2 O were emitted respectively to Gondola, for the district of Manica approximately 1.1, 0.005 were emitted , 0.00014 tons of CO 2, CH 4, N 2 O respectively and in the district of Tambara 1.09 tons of CO 2 were emitted; 0.005 ton of CH 4 and 0.001 ton of N 2 O. For the direct method, CO 2 emissions vary from 720- 860 ppm in the districts of Tambara and Manica to the district of Gondola, ranging from 630-690 ppm. It is concluded that the behavior of the fire, that is, less intensity and spread of the fire was influenced by the characteristics of the combustible material. Given the amounts of emissions found in this study, it is noted that the fires were less intense, when compared to those occurring in the dry season and that smaller amounts of CH 4 and N 2 O were emitted. To this end, it is recommended that studies be carried out similar in other provinces of the country and that in a Remigio Nhamussua October 2015 vEstimates of Greenhouse Gas Emissions from Forest Fires 2 years apart, the same study is carried out in the same areas in order to assess vegetation dynamics after the passage of the fire. (TRADUÇÃO NOSSA)