Woody debris is a critical component of natural forests, with an important function in land reclamation to control erosion and enhance diversity and function of newly developing ecosystems. Combined with cover soils, woody debris can play a significant role in plant community development, as cover soil is a source of inexpensive and ecologically adapted propagules. As we develop woody debris application as a land reclamation tool, its impacts on cover soils over time need to be documented. This study assessed how woody debris volume, types (Picea mariana, Populus tremuloides), and size influenced soil properties, and vegetation structure and composition in forest floor‐mineral mix (FFM) and peat‐mineral mix (PMM) cover soil types 4–5 years after oil sands reclamation. Soil chemical and physical properties were significantly affected by cover soil types, whereas no woody debris effects were evident. FFM cover soil was associated with greater vegetation cover, plant species richness, composition, and woody plant density than PMM. Nonmetric multi‐dimensional scaling and multi‐response permutation procedures revealed plant community compositional differences only for cover soil types. Presence of early‐to‐late and mid‐to‐late seral species 4–5 years after reclamation in FFM and PMM indicated community development trajectories were following typical early successional processes of boreal forests of the region. Woody debris type, size, and volume application had small or no impact on vegetation development. Although FFM cover soil was more effective than PMM, further long‐term research to evaluate impacts of woody debris on vegetation development would be important to affirm its use for reclamation.

Coarse woody debris (CWD) and cover soils are used to expedite ecological processes in reclaimed boreal forests after oil sands mining. Soil water content and soil temperature are considered key factors for revegetation during mine reclamation as they impact soil surface and atmosphere interactions and plant growth. However, the effects of CWD and cover soils on soil water content and temperature are not well studied. This study assessed the impact of CWD size (large, small) and type (spruce: Picea mariana, aspen: Populus tremuloides) on soil water content and temperature in two soils constructed with forest floor-mineral mix (FMM) and peat-mineral mix (PMM)) at oil sands reclamation sites. Annual and summer precipitation showed year-to-year variability; mean air temperature did not. Soil cover type had a greater impact on moderating soil water content than CWD, with PMM having a stronger influence on water content and temperature than FMM. Adding CWD increased soil water content more in FMM than PMM, and the effect on soil temperature was mostly observed during the summer months. In PMM, spruce small CWD was associated with greater water content, whereas there was no distinct differentiation between CWD size and type in FFM. This study suggests application of CWD in FMM would be more beneficial than in PMM for reclamation.

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