Allometric Models for Estimating Biomass and Carbon in High-Andean Living Fences: Contributions to Climate Change Mitigation from Agroforestry Systems

This study was conducted at the experimental station of the Colombian Potato Producers Federation (FEDEPAPA), located in the village of Obonuco, municipality of Pasto, Department of Nariño, Colombia, at 1°13′ N latitude and 77°16′ W longitude, 2710 m a.s.l., with an average temperature of 12–13 °C. Aboveground biomass production, including stem, branches, and leaves, root biomass, and fixed carbon were evaluated in Acacia decurrens, Alnus jorullensis, Baccharis trinervis, Ulex europaeus, and Tecoma stans, established in a three-year-old double-row living fence arrangement, planted at 1 m between rows and 1 m between trees in a triangular pattern. Biomass estimation was performed using a destructive sampling method, extracting five trees per species in each evaluation; additionally, allometric biomass models were developed based on dasometric variables recorded in the field. The results showed that Acacia decurrens and Alnus jorullensis presented the highest biomass values, with 4.43 and 1.32 t ha⁻¹, respectively, as well as the highest fixed carbon contents, with 2.21 and 0.66 t ha⁻¹. The allometric models developed for these two species showed an adequate goodness of fit with diameter and height data, confirming their usefulness as tools for estimating biomass and carbon in high-Andean living fences and their potential contribution to agroforestry-based climate change mitigation strategies.