In this study we explored how various environmental and technical factors affect forest succession and biomass recovery in passive restoration (PR) and active restoration (AR) of the Atlantic Forest, Brazil, as well as how the uncertainty tied to forest succession influences restoration costs. The research was conducted on farms purchased for mandatory biodiversity restoration in Minas Gerais state from 2008 to 2021. Although these restoration activities cannot generate carbon credits (no additionality), they nonetheless provide valuable data for understanding the costs associated with restoration of the Atlantic Forest for generation of carbon credits. We developed a chronosequence to investigate the effects of isolation duration and planting strategies on forest restoration success. A Random Forest model was implemented to evaluate succession dynamics and identify the primary drivers of restoration success. We also evaluated the relative costs of AR and PR by integrating aboveground carbon growth models with accumulated restoration expenses. Over a span of 13 years, natural vegetation rose by 9.25%. AR accelerates forest succession, but this is contingent upon a preceding extended isolation period. The success of restoration is largely affected by how close an area is to remaining forest fragments and its elevation, emphasizing the importance of being close to seed sources, even for AR where seedlings are planted. Factors such as distance to roads and rivers, slope, aspect, and age of isolation are also important in understanding reforestation success. Consistent with earlier research, PR decreases the cost per ton of carbon captured through the restoration process (18 USD/t CO 2 e for PR vs 61 USD/t CO 2 e for AR, considering the average carbon curve). An integrated approach combining passive and active restoration of the Atlantic Forest biome, tailored to geographic location and key success factors, offers an attractive strategy for reducing reforestation costs and associated carbon credit prices. • Greater forest cover and lower fragmentation strongly increased passive restoration success. • Plantings accelerated succession after long isolation periods; isolation age predicted recovery. • Distance to forest fragments was the main restoration driver, followed by terrain and roads. • Passive restoration lowered carbon offset costs, enabling viability at 57% lower carbon prices. • Carbon sequestration costs exceeded market prices, requiring regulatory support for viability.
Dias et al. (Thu,) studied this question.