Effects of logging residue treatment and mechanical site preparation on below- and aboveground biomass production in Scots pine stands

The increasing demand for renewable energy has led to a surge in biomass harvesting from forest ecosystems. However, intensive biomass extraction, especially logging residue (LR) removal and mechanical site preparation (MSP), may affect long-term forest productivity. This study aimed to assess the effects of three MSP methods (plowing and planting in furrows, disc trenching, bedding and planting in raised beds) and three LR management strategies (complete removal, leaving residues, and comminution) on above- and belowground biomass production in Scots pine (Pinus sylvestris L.) stands 17 years after planting. The experiment was conducted in northwestern Poland on Albic Brunic Arenosols with low fertility. The experiment consisted of 27 plots in a randomized complete block design. The tree measurements included diameter at breast height (DBH), tree height, stand density, basal area, stand volume and biomass, which were analyzed using two-way ANOVA. Significant differences in DBH and tree height were detected between the MSP methods. Furrowing resulted in the greatest growth, whereas bedding produced the lowest DBH and height. Among the LR treatments, tree height was lowest for comminution. However, no significant differences were found in stand biomass, basal area, or stand volume across the treatments. These findings suggest that the MSP and LR management methods have short-term effects on tree growth but do not significantly influence long-term stand productivity. These results highlight the importance of performing long-term experimental trials to assess the sustainability of forest management practices.