Soil compaction by forest management creates hotspots of BVOC emissions in a temperate mixed forest

Soil emissions of biogenic volatile organic compounds (BVOCs) and their impacts at the ecosystem scale have been intensively studied. However, less attention has been paid to how forest management practices alter soil BVOC exchange by modifying soil physical and biogeochemical properties. In managed forests, timber harvesting operations frequently create skid trails, where repeated machine traffic leads to soil compaction and impaired drainage, potentially altering oxygen availability and microbial processes.

In this study, we investigated how soil property changes associated with skid trails influence BVOC exchange from the forest floor of the ECOSENSE forest, a temperate mixed forest. We combined field measurements of soil–atmosphere BVOC exchange at waterlogged skid trails and adjacent undisturbed forest floor with laboratory incubations of intact soil cores under controlled oxic and anoxic conditions.

Our results show that skid trail soils exhibit distinct BVOC emission patterns compared to well-drained forest soils. In particular, emissions of aromatic compounds, including toluene and the aromatic monoterpene p-cymene, increased markedly under waterlogged and oxygen-limited conditions. Emissions of several monoterpenes, such as α-pinene, camphene, limonene, and δ-3-carene were also enhanced.

Although skid trails cover only a small fraction of the forest area, our findings indicate that they can act as BVOC emission hotspots within forest ecosystems. This highlights that small-scale heterogeneity introduced by forest management can substantially influence ecosystem-level BVOC budgets and forest–atmosphere interactions.