## 4 Discussion
### Deforestation and Forest Degradation Rates  
The study found that forest degradation consistently outpaces deforestation in both areas, a trend that is sometimes overlooked in broader assessments of forest loss [11]. In their 2020 study, [PERSON] et al. reported that long-term forest degradation in the Brazilian Amazon has surpassed deforestation, affecting an estimated 337,427 km\({}^{2}\) of forest between 1992 and 2014, compared to 308,311 km\({}^{2}\) lost through deforestation [66]. The same trend was observed by [PERSON] et al., who estimated that during 2010-2019, the Brazilian Amazon experienced a cumulative gross loss of 4.45 Pg C against a gross gain of 3.78 Pg C. In their results, forest degradation (73%) contributed three times more to the gross AGB loss than deforestation (27%) [67]. This highlights the significant impact of degradation on carbon stocks and underscores the importance of considering both deforestation and degradation in forest monitoring efforts.  
A significant driver of forest degradation in the Amazon is illegal selective logging, as there is a high demand for valuable timber species, especially in international markets. This practice involves the removal of targeted high-value tree species, which disrupts the forest structure and composition. The creation of access roads and tree extraction open the forest canopy, which leads to increased light penetration and drier conditions on the forest floor, making the forest more susceptible to fires, especially during drought periods [68; 69; 70], leading to more degradation and eventual forest loss.  
In this study, Secondary Forests, which often result from previous disturbances like logging or fire, were observed to have the largest area gain in Manaus over the study period (Table 6), which shows a great level of forest degradation in the area. This may be due to the city's strategic location and status as a major economic hub placing it at risk of increased forest disturbance as development continues to expand in this area [71; 72].  
The high yearly rates of deforestation and degradation observed in Porto Velho, compared to Manaus, can be partly attributed to its location within the \"arc of deforestation,\" a region along the southern and eastern edges of the Amazon that has been particularly vulnerable to forest clearance [3]. Additionally, infrastructure projects like the reconstruction of the BR-319 highway connecting Porto Velho to Manaus have been associated with increased land speculation and forest clearing, even before the road's completion [73; 74].  
The primary drivers of forest loss observed in our study areas mirror those identified in the broader Amazon region. Agriculture, particularly the expansion of pastureland for cattle reaching, emerged as the dominant force behind deforestation, consistent with findings from [PERSON] et al., who attributed 63% of forest disturbance in the Brazilian Amazon to pasture conversion between 2000 and 2013 [75]. The creation of pastureland is also frequently driven by land speculation, where areas are deforested to create pastures to quickly sell the land at inflated prices to crop producers, generating a complex land rights problem for the region. Deforestation derived from this land use was highly observed in Porto Velho by this study, as the city is a major cattle producer in the region.