The impact of heavy traffic on forest soils: A review

Forest soils can suffer from various threats, some of which are human induced. Although mechanized harvesting allows for high productivity, it may also seriously damage forest soils. In recent decades, the use of powerful and heavy machinery in forest management has increased exponentially. The extent, degree, and duration of direct and indirect effects of heavy traffic on soils depend on several factors, such as soil texture, moisture, and organic matter content, slope of the terrain, type and size of vehicles, wheel inflation pressure, tire shape, and number of vehicles trips. Topsoil compaction and the alteration of ground morphology are crucial direct effects of forest harvesting carried out using heavy equipment. Soil compaction results in reduced porosity, which implies limitations in oxygen and water supply to soil microorganisms and plants, with negative consequences for soil ecology and forest productivity. Compaction, especially when confined in ruts, also has dramatic ramifications in terms of runoff and erosion of the most fertile soil compartment (i.e., the top soil). In compacted soils, forest regeneration can be impeded or even prevented for long time periods. A detailed review of the abundant although still insufficient literature on machinery-induced negative effects on forest soils and their ramifications for forest ecology and management is provided here, along with recommendations for best practices to limit such damage.