In the last years, forest degradation in the Brazilian Legal Amazon has shown significant values, frequently higher than deforestation. From August 2006 to July 2018, the degraded area totaled 191,632 km², representing 2.4 times the 89,501 km² deforested in the same period. The impacts of degradation include changes in the forest structure, carbon stocks, and biodiversity loss, affecting the CO2 balance and future climate changes. This thesis investigates the factors underlying the Spatio-temporal distribution of forest degradation in this region in recent years and how they impact CO2 balance in the region. Droughts and deforestation are some of the main factors linked to forest degradation. Then, we analyzed how the relationship between these factors and forest degradation evolved during this period by analyzing three indicators: water deficit anomaly indicator, historical clear cut deforestation indicator, and protected areas indicator. We also analyzed temporal trajectories of forest degradation from August 2006 to July 2016 in the Brazilian Amazon. We assessed their impact on the regional carbon balance, combining the degradation process with deforestation-related processes (clearcut deforestation and secondary vegetation dynamics), using the spatially-explicit INPEEM carbon emission model. Finally, we explored socio-economic and environmental factors that influence forest degradation spatial distribution and project scenarios of degradation and CO2 emissions for the Brazilian Amazon. Our results pointed out that 80% of the degradation events occur in areas classified as drought condition areas during the driest years. In contrast, forest degradation in these areas does not exceed 50% when considering the entire period. On the other hand, the relationship between degradation and historical deforestation were, on average, 67% during the whole period. Additionally, our results also show that, on average, 25% of the degradation occurred in Indigenous Territories and 9% in Conservation Units. The trajectory analysis showed that 13% of the degraded area ended up being cleared and converted in the period, and 61% of the total degraded area experienced only one event of degradation throughout the whole period. Net emissions added up to 5.4 Gt CO2, considering the emissions from forest degradation and deforestation, absorption from degraded forest recovery, and secondary vegetation dynamics. The results show an increase in forest degradation’s contribution to net emissions towards the end of the period, related to the decrease in clear-cut deforestation rates, decoupled from the forest degradation rates. The spatially-explicit model allowed us to explore socio-economic and environmental factors that influence forest degradation spatial distribution and project future scenarios of degradation and CO2 emissions to the Brazilian Amazon. We built sustainable and fragmentation land use scenarios and estimated their impacts on CO2 emission. At the end of the simulation, most of them presented a portion of up to 10% of forest degradation. However, in the sustainable scenario, it was still possible to observe intact forest regions, especially in eastern Amazonas. Our results also showed that while net CO2 emissions from 2019-2050 added up 0.74 Gt CO2 in a sustainable scenario, in a fragmentation scenario, this value reached 22.63 Gt CO2.
Redes Sociais