Short‐term soil responses and site conditions to inverted mounding on peatland linear features in Alberta, Canada

Introduction Seismic lines represent one of the most extensive and persistent anthropogenic disturbances in boreal peatlands, limiting forest regeneration and altering key ecosystem functions. Inverted mounding is increasingly applied to elevate planting microsites above shallow water tables, yet evidence on short‐ to medium‐term biophysical responses remains limited. Objectives We assessed the effects of inverted mounding on soil properties, mound persistence, and microsite development over 5 years following treatment in a boreal treed peatland. Methods An experimental mounding trial was established in northern Alberta, Canada, using two mound sizes (30–40 cm, 50–60 cm high) and an untreated control across five linear corridors, with adjacent peatland reference sites. Soil gravimetric water content, bulk density, and pH were measured annually (2019–2023) from mounds and in untreated and reference sites. Mound and pit dimensions were also monitored. Results Inverted mounding significantly altered site conditions regardless of mound size. Mounds were consistently drier than surrounding areas, suggesting improved moisture conditions for tree establishment. Soil pH declined over time toward reference values, indicating partial recovery of acidity. In contrast, bulk density increased with mound settling, eventually exceeding untreated conditions. Within 6 years, small and large mounds lost 51.3% and 44.3% of their height, respectively. Excavation pits developed into persistent water‐filled pools, expanding by year six and occupying 18%–23% of the corridor surface, thereby reducing substrate availability for non‐aquatic vegetation. Conclusion Inverted mounding provides short‐term improvements in microsite moisture but introduces trade‐offs associated with soil compaction, mound degradation, and altered hydrology.