Evaluación económica y ambiental de un sistema silvopastoril de Eucalyptus dunnii para obtención de trozas de diámetros finos en baja densidad

This research aims to evaluate, from both and economic and environmental perspective, a Eucalyptus dunnii plantation within a low-density silvopastoral system intended for pulpwood production. Eight permanent plots were established, each containing 30 trees, and two forest strata were identified based on topographical differences and soil types. Measurements of height (Ht) and circumference at breast height (CBH) were taken at 4,1 and 5,0 years after planting to calculate other relevant variables such as basal area (BA), diameter at breast height (DBH), and volume (V). Three trees were sampled in each plot, representing three different diameter ranges; wood density and carbon content were measured for each diameter class (DC) using spectrophotometry in the laboratory. Statistical analysis showed no significant differences in the dasometric variables (DBH, Ht, V) between the studied strata. It was found that 45,33% of the forest biomass in the silvopastoral system consisted of carbon, mainly concentrate in the tree stem. While no differences were found in the carbon percentage per individual DC, the central DC with a range of 10,4 – 18,0 cm of DBH accumulated the most carbon due to its higher frequency and final volume in the system. Carbon sequestration averaged 10,4 Tn CO_2e/ha/year over the 5 years of the plantation, while emissions from livestock were 3,5 Tn CO_2e/ha/year, resulting in a positive carbon balance of 6,9 Tn CO_2e/ha/year for the years 2017-2022. However, when considering the entire property (3.281 ha), the carbon balance was negative (-11.108 Tn CO_2e/year), underscoring the importance of expanding integrated tree systems to offset these emissions. Financial analysis demonstrated the projects economic viability, with an expected Net Present Value of $2.760 USD assuming a 6% opportunity cost and an Internal Rate of Return of 6,2%. Additionally, the positive impact of potential carbon credit generation and subsequent sale on project viability was evaluated. Considering carbon sequestration by these systems could benefit producers through the production of low-greenhouse gas emissions meat.