The quantity and quality of dead wood in the Roztocze National Park – the role of the stand's species composition, its density and conservation regime

Dead wood, particularly coarse woody debris (CWD), is a key structural component of forest ecosystems, supporting biodiversity, carbon storage, and nutrient cycling. Its quantity and quality are strongly shaped by forest management, species composition, and stand development. This study assessed the volume, structure, and decomposition stages of dead wood in Roztocze National Park (RNP), with a particular focus on the effects of conservation regime, stand age, species composition, and stand density. Field data were collected in summer 2019 on 315 circular plots (0.04 ha each) distributed systematically across the RNP. Dead wood was inventoried as standing dead wood, lying dead wood, and stumps, classified by tree species, diameter classes, and five stages of decomposition. Statistical analyses were conducted using general linear models to identify the main drivers of dead wood abundance and structure. The mean volume of dead wood across the Park was 44.8 m3ha–1, with a wide range (0−345 m3ha–1). Lying dead wood accounted for 62% of total CWD volume, standing dead wood for 33%, and stumps for 5%. Most dead wood consisted of large−diameter elements (>20 cm), which are particularly important for saproxylic organisms. Silver fir had the highest contribution of dead wood, followed by European beech, despite Scots pine being the most common tree species in the stands. Dead wood resources were strongly influenced by the conservation regime: strictly protected stands contained over three times more dead wood (115.5 m3ha–1) than actively managed stands (37.1 m3ha–1). Stand age and dominant tree species were significant predictors of dead wood volume and decomposition stage, while basal area had no significant effect. Older stands and strictly protected areas were characterised by higher proportions of advanced decay stages. The results demonstrate that long−term strict protection substantially enhances both the quantity and ecological quality of dead wood. Nevertheless, the relatively low−intensity management applied in the active protection zone also maintains dead wood volumes close to biodiversity thresholds reported for temperate European forests. These findings highlight the importance of stand age, species composition, and conservation regime in shaping dead wood dynamics in protected forest landscapes.