Growth and survival of potential tree species for carbon-offset in degraded areas from southeast Brazil

Brazil must restore 12 million hectares of degraded areas by 2030 to meet its goal of the Paris Global Climate Agreement (PGCA). In view of this, the development of mixed planting projects related to carbon-offset in degraded areas is increasing, which demonstrates environmental and social responsibility of corporate and governmental organizations. Despite the great potential of mixed restoration plantations to mitigate climate change, Brazil must overcome major challenges in achieving the ratified goals of the PGCA as well as the effectiveness of its carbon-offset projects. In this context, this study has focused on the evaluation of the growth and survival of tree species in a carbon-offset plantation from a degraded area in southeastern Brazil. Five-hundred-and-nine seedlings (15 forest species) were planted in a completely randomized design. Diameter at the soil level and height of individuals were measured at 40 months. Three individuals of each species were selected and was scaling by a non-destructive method. Timber volume was estimated from the sum of the volume of the sections of the individuals, obtained by the Smalian formula. The average annual carbon increment of the individuals was estimated by the equation adjusted from the Schumacher & Hall model. The potential of carbon-offset of the tested plants was evaluated from the SP and μC analysis. The REML (Restricted Maximum Likelihood)/BLUP (Best Linear Unbiased Prediction) method was used to predict μC values for species ordering with carbon -offset potential. Survival was 47.54% at 40 months. The carbon stock of the planting was 2.60 ± 6.2 Kg C individual⁻¹, and the average annual increase in carbon (AAIC) was 0.78 Kg C individual⁻¹year⁻¹. The AAIC value was lower than the average value stipulated for carbon-offset projects (6.0 Kg CO₂ individual⁻¹ year⁻¹). Pioneer species contributed more to carbon storage than non-pioneer species.