Abstract: The Andean montane forests provide a wide range of ecosystem services like water supply, carbon sequestration, and biodiversity preservation. Restoration of these forests is critical due to their degraded state and the need to recover, maintain and enhance the ecosystem services they provide. However, we lack understanding of aboveground biomass (AGB) accumulation in restored Andean montane forests. AGB is a key indicator of ecosystem productivity and provides essential data on vegetation carbon stocks, permitting the assess successfulness of restoration efforts. In 2010 the initiative Más Bosques para Medellín was formulated in Medellín City, tropical Andes, Colombia, aiming to restore the forests located in the surrounding rural areas of the city, with interest in preserving the ecosystems services like water supply. The project established 548 ha of mixed plantations with native species. After 13 years, our study aims to developed in situ allometric equations and to evaluate AGB accumulation to assess restoration performance. We measured, harvested, and weighted 144 individuals from these arrangements to fit a general equation for the project and six specific equations for each one of the six most frequent species. The AGB had a positive correlation with diameter at breast height (D), total height (H) and specific wood density (WD). The best general equation uses D and WD as predictors (R² = 0.928). The specific species equations certainly responded to the functional traits of each species. Using the latest inventory of permanent plots of the project we estimated a mean AGB accumulation of 41.91 ± 30.34 Mg ha^–1 and a total accumulation of 22,996.05 Mg of AGB for the 548 ha. We compared these results with studies developed for natural forest in the region and other land covers. We found contrast behaviors in the AGB accumulation across our study zones. The developed equations have broad applicability across the Andes region, offering valuable insights for similar restoration initiatives. Furthermore, will facilitate the assessment of current restoration efforts and inform scientifically based decisions for future mixed plantation practices.

Key words: Aboveground biomass, Allometric equations, Active restoration, Mixed plantations, Quercus humboldtii