Effect of planting density and tree species selection on forest bioenergy systems: tree growth, nutrient storage and wood chemical properties

This study based on woody biomass was conducted under an experimental design of randomized complete blocks with two species, Eucalyptus saligna and Eucalyptus tereticornis, in three planting densities, 5000 trees ha⁻¹, 10 000 trees ha⁻¹, and 20 000 trees ha⁻¹. Data were collected at 3, 12, and 24 months and growing relationships were analyzed. Adobe ground biomass, soil carbon reserve, plant issue nutrients, and woody biomass were determined. Results showed statistically significant differences between species in biomass production, obtaining values from 36.80 to 117.42 Mg ha⁻¹ in E. tereticornis and 36.10 to 107.67 Mg ha⁻¹ in E. saligna. Optimum planting density for both species proved to be 10 000 trees ha⁻¹, which showed better biomass accumulation and growth performance in addition to lower mortality, and less impact on productivity. Regarding soil nutrition, it was determined that as crop density increased, the loss of nutrients (N, P, K, Ca) increased, with a loss of up to 33% in 24 months in the density of 20 000 trees ha⁻¹. For both species, the treatment of 10 000 trees ha⁻¹ provided the highest concentration of organic matter in the top 20 cm of soil. Finally, wood chemical aspects did not show differences in the properties with any treatment.