Integrating dendrometric traits and wood density to predict biomass productivity, bioenergy yield, and carbon sequestration in hybrid Populus clones

Accurate prediction of biomass productivity and bioenergy potential remains a major challenge in plantation forestry, particularly for fast-growing species such as hybrid Populus where tree architecture, wood properties, and genetic variability interact in complex ways. This study evaluates the relationships between dendrometric traits and biomass-based bioenergy indicators across 19 hybrid poplar clones cultivated under northern European conditions. Diameter at breast height (DBH), tree height, stem volume, stem dry mass, branch dry mass, and wood density were used to estimate above-ground biomass, energy yield, carbon stock, and CO₂-equivalent mitigation potential. Substantial genetic variability was observed among clones, with mean above-ground biomass reaching 214.6 t ha⁻ 1 and ranging from 71.8 to 456.9 t ha⁻ 1 . DBH showed the strongest correlation with biomass accumulation (r = 0.768, p < 0.001), followed by stem volume (r = 0.724) and wood density (r = 0.647). A multiple regression model integrating stem volume and wood density explained 94.8% of the variation in biomass (R 2 = 0.948), Although volume and density explained a high proportion of biomass variation, this association should be interpreted as explanatory because biomass estimates are mathematically related to these variables. The model is therefore best viewed as an explanatory framework rather than a fully independent predictive model. Accounting for branch biomass increased estimated biomass, bioenergy yield, and carbon sequestration estimates by 24.63% compared with stem-only assessments, demonstrating that branch exclusion can lead to substantial underestimation of stand-level resource availability in biomass-oriented plantation systems. The clones SvSF Po11, SvSF Po12, and Nyd3261-Degrosso exhibited the highest biomass productivity and energy potential. These results demonstrate that integrating dendrometric traits with wood density provides a robust predictive approach for biomass and bioenergy assessment in hybrid poplar plantations.