Speaker
Description
Soil compaction caused by forestry machinery poses a significant challenge to the sustainability of forest ecosystems, affecting not only physical soil properties such as pore space and water retention but also biological activity—a key driver of nutrient cycling and soil regeneration. Traditional methods for assessing biological activity are often invasive or labor-intensive. A promising alternative is ecoacoustics, which uses soil microphones and indices like the Acoustic Complexity Index (ACI) to non-invasively and continuously monitor the acoustic activity of soil organisms. This approach offers a way to evaluate soil health and the impacts of different management intensities. This study addresses two central questions: 1. Long-term effects of skid trails: How does machinery traffic during timber harvesting influence biological activity in sandy forest soils, both immediately after compaction and years after last use? and 2. Comparison of forest road types: Do different forest infrastructure types (natural trails, skid trails, forest roads) differ in their impact on acoustically measurable biological activity?
The hypotheses suggest a reduction in biological activity due to compaction (measured via ACI) and differences between road types based on usage intensity and substrate composition. Data collection took place in two study areas within the Schorfheide-Chorin Biosphere Reserve, locates in the federal state of Brandenburg, Northeast Germany:
• Skid trails: Acoustic measurements (soil microphones, ACI calculation) and soil physical parameters (density, pH, humus content) were recorded on freshly trafficked and long-unused skid trails.
• Forest road types: Natural trails, skid trails, and forest roads were compared in terms of acoustic complexity (ACI) and microclimatic factors (soil/air temperature, moisture).
Preliminary results reveal no significant differences in acoustic complexity (ACI) between trafficked and untrafficked areas or among road types—despite visually apparent trends (e.g., higher ACI values on skid trails). This raises questions about the sensitivity of the method: While classical soil parameters (density, humus content) responded to compaction, acoustic activity remained largely unaffected. Possible explanations include the overall low biological activity in sandy soils, spatial heterogeneity of soil organisms, limited sample size, or methodological constraints (e.g., sensor sensitivity, noise interference).
However, these findings highlight the potential of ecoacoustic methods as a non-invasive tool for assessing soil health. At the same time, they underscore the need for methodological refinements, which will be included in our further research. In the long term, ecoacoustics could play a bridging role between research and practice, enabling forest managers to monitor the impacts of machinery traffic or infrastructure measures in real time and across large areas—a critical step toward adaptive, soil-conserving management strategies
| Keywords | Bioacoustic; SoilCompaction; AcousticComplexityIndex(ACI); SoilBulkDensity |
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