Biomass and carbon recovery of secondary forest in a Montane Subtropical Forest of North Eastern India

Shifting cultivation has been the primary cause of forest degradation and destruction. Secondary forests are spreading around the globe and hence the importance of secondary forests has been recognised and its growth could help to alleviate the effects of deforestation and supplement existing conservation efforts. Various complex processes occur in regenerating secondary forests; in the initial stages, the forests are dominated by herbs and shrubs, and in the latter stages, trees predominate. The current study was carried out in Reiek forest, Mizoram, India at various phases of succession following abandonment in order to better understand biomass and carbon recovery in differently aged fallow periods (FP) and natural forest (NF). Fallow ages were divided into four categories: FP03, FP07, FP11, and FP15 (i.e., 0–3, 4–7, 8–11, and 12–15 years old), with three additional experimental plots in NF for comparison. In this study the biomass and carbon in standing vegetation were estimated. The soil organic carbon (SOC) was also quantified. We found that all the fallow ages and NF were significantly different in biomass, carbon stock, and SOC. Longer fallow period (FP) stores more biomass and carbon than shorter FP. Total biomass stock (TBS) of more than 42% and total carbon stock (TCS) of more than 43% of NF was achieved in plots abandoned for 12–15 years. Although SC fallow takes longer period to recover to a forest, they perform a crucial role as a carbon sink in the atmosphere.