Maintaining the long-term productivity of forest soils is essential for future forest growth. Organic matter losses and decreases in aeration porosity (soil compaction) are considered to be the fundamental factors contributing to observed declines in forest productivity (Powers et.al.1990).
On medium-to fine-textured soils, compaction of the mineral soil produces a series of linked effects on the soil environment (Bates et al.1993, Greenway 1999). When wet, these soils have low soil strength, and slow drainage when saturated. Machine traffic during wet conditions causes loss of macropores, resulting in decreased gas exchange and internal soil drainage. Prolonged saturation slows soil warming, and reduces soil aeration.
The consequences of changes to these soil properties are not well documented, particularly in boreal ecosystems. Changes to soil moisture regimes and nutrient availability will also result in changes in plant communities. Plants may be regarded as sensitive integrators of all the environmental conditions created by forest harvesting practices.
After harvesting in the boreal forest, there can be increases in plants such as bluejoint (Calamagrostis canadensis) which compete with white spruce seedlings, often resulting in reduced spruce survival and growth (e.g., Coates et al.1994). Changes to site conditions may also affect the role of vegetation in providing habitat and food for insects, birds and wildlife. Changes in plant communities can influence the essential functions of plant roots and organic matter in maintaining soil structure and nutrient availability.
This note describes the initial effects of soil compaction and organic matter removal on plant communities in aspen ecosystems of northeastern British Columbia. The Boreal Long Term Soil Productivity Study is part of an international research effort with sixty-two installations in North America (Powers 1999).
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Updated December 17, 2008