Influence of slope on physical soil disturbance due to farm tractor forwarding in a Hyrcanian forest of northern Iran

Abstract

© iForest -Biogeosciences and Forestry IntroductionThe entry of forestry machineries into forest has resulted in some cases in levels of soil disturbance that may have adverse effects on forest ecosystems and subsequently on long-term tree growth (Miller & Anderson 2002, Landsberg et al. 2003, Ilstedta et al. 2004, Murphy et al. 2004. Numerous studies have documented changes in physical soil properties following harvesting machine traffic, such as increased soil compaction, soil displacement, rutting and soil profile disturbances (Adams & Froehlich 1984, Wronski & Murphy 1994, Rab 1996, Rohand et al. 2004, Eliasson 2005, Susnjar et al. 2006, Eliasson & Wasterlund 2007, Horn et al. 2007, Wang et al. 2007, Zenner et al. 2007, Ampoorter et al. 2010, 2012, Picchio et al. 2012. For instance, soil compaction, in which soil pores (especially macropores) are destroyed and surface aggregates are broken down (Ampoorter et al. 2010), depend on the soil texture and moisture at the time of harvest (McNabb et al. 2001, Bock & Van Rees 2002, but also on the number of machines passing on a specific point. Generally, soil compaction occurs in the first ten passes of a vehicle, but most of the compaction occurs in the first three trips; subsequent passes generally have little additional effect (Gayoso & Iroume 1991, Eliasson 2005, Eliasson & Wasterlund 2007, Ampoorter et al. 2010. So it would be appropriate to concentrate machine traffic on carefully designed skid trails in such a way to minimize the affected area and leave most trees undisturbed (Zenner & Berger 2008, Ampoorter et al. 2010.It is unclear, however, to what extent the slope gradient (i.e., longitudinal and transversal slope) of the skid trail and the direction of machine traffic (i.e., uphill vs. downhill) could modify the impacts of vehicle traffic on the soil. Whereas some studies have failed to document an effect of slope on bulk density following harvesting traffic (e.g., Sidle & Drlica 1981, Jamshidi et al. 2008, others have shown that soil disturbances increase with slope gradient (Ezzati et al. 2012), possibly because machines slip more and remain in a given place for a longer time on steep terrain, causing soil pulling and dragging (Gayoso & Iroume 1991). Thus, steepness may have an even stronger effect on soil disturbance than that of the soil moisture (Krag et al. 1986), but possibly less so than that of the traffic intensity (Ezzati et al. 2012).Soil disturbance is also strongly affected by the type of harvesting equipment used. Small-scale harvesting technology, such as farm tractors or better small skidder or other specific machines (such as ATV), is thought to result in lower levels of residual stand and soil damage because the equipment is typically smaller and lighter than regular skidders (Updegraff & Blinn 2000, Savelli et al. 2010, Spinelli & Magagnotti 2012. A recent study dealing with soil compaction has found that the highest relative increase in bulk density was associated with the use of bulldozers, the lowest with the use of a forwarder, a...

How and How Much, Do Harvesting Activities Affect Forest Soil, Regeneration and Stands?

“…The physical, chemical and biological properties of the forest soil change as a result of harvesting operations, and this is commonly referred to as soil disturbance [4, [16][17][18][19]. Chemical and biological changes occur in the soil after physical modification.…”

Impact of wheeled and tracked tractors on soil physical properties in a mixed conifer stand

“…Ruts are usually more marked by wheeled vehicles than by tracked vehicles, due to higher pressure on soil, and for moist soil than for dry soil, due to the lubricant action of water on particles (Jansson & Johansson 1998, Marchi et al 2014. Few studies about the impact of logging on soil have been conducted in Mediterranean countries (e.g., Picchio et al 2012, Jourgholami et al 2014, which are among the most prone to erosion worldwide (Kosmas et al 1997, Cerdà et al 2010, Shakesby 2011. Moreover, the studies on soil compaction and rutting in relation to the machine type (tracked vs. wheeled) showed contrasting results (Cambi et al 2015).…”

“…Soil compaction is a major source of human-induced forest soil degradation (Bagheri et al 2011), even though moderate compaction of loose soils can result in improved soil quality (Gomez et al 2002). Harvest-induced soil compaction depends on several factors: soil type (Berli et al 2004, Sakai et al 2008, Magagnotti et al 2012, soil moisture (McNabb et al 2001, Han et al 2006, Ampoorter et al 2012, content of soil organic matter (Arthur et al 2013), number of machine passes (Williamson & Neilsen 2000, Wallbrink et al 2002, Han et al 2006, terrain steepness and direction of travel (Jourgholami et al 2014), characteristics of the equipment and yard organization (Picchio et al 2012, Marchi et al 2014, and machine speed and wheel slippage (Alakukku et al 2003, Eliasson 2005. Soil compaction and reduction or removal of the top organic horizon often causes poor regeneration on skid trails (Rab 1996, Startsev & McNabb 2000.…”

Estimating machine impact on strip roads via close-range photogrammetry and soil parameters: a case study in central Italy

“…The physical parameters of soil are usually determined by means of soil sample collection and analysis, or measured using specific instruments, such as penetrometers and scissometers (Picchio et al 2012, Venanzi et al 2016, or by means of manual measurements of cross-sectional and longitudinal profiles on skid trails (Koren et al 2015). Although these methods have been improved over time (Jourgholami et al 2014), they are time consuming and costly. Moreover, these methods may affect the study area when repeatedly applied.…”

“…Most studies concerning soil degradation due to forest operations have examined the physical parameters of soil, such as bulk density, total porosity, macro and micro porosity, shear and penetration resistances, and infiltration capacity (Alakukku et al 2003, Ampoorter et al 2007, Jourgholami et al 2014, Marchi et al 2014. The physical parameters of soil are usually determined by means of soil sample collection and analysis, or measured using specific instruments, such as penetrometers and scissometers (Picchio et al 2012, Venanzi et al 2016, or by means of manual measurements of cross-sectional and longitudinal profiles on skid trails (Koren et al 2015).…”