Presentation Information
[O12-P31]Effects of Human Trampling on Mountain Trail Erosion and Degradation
-Kinematic Analysis Using SPLYZA Motion-
*Meilin Ding1 (1. Kyoto Prefectural Sagano High School)
Keywords:
Soil erosion,walking,impulse,trail design
Introduction
Deer (Cervus nippon) are known to feed on understory vegetation and, when such vegetation is scarce, on leaf litter. As a result, ground surface cover decreases, leading to deterioration of soil physical properties and increased soil erosion (Onda and Yamamoto, 1998). In Japan, where hiking is popular, human trampling in forested areas has also been reported to negatively affect surface conditions, causing the expansion of bare ground and soil compaction (Takatsuki, 2015). Furthermore, in the Sagano High School Woods for Field Studies, long-term research activities have created trails, and soil erosion has become a serious issue in some areas (Sayama, 2020).
To prevent soil erosion, various measures to reduce human impact can be considered. In order to enhance the sustainability of research activities, it is necessary to examine appropriate trail design.
The objective of this study was to estimate the load exerted on the soil surface by human walking and to examine appropriate walking methods and trail design. Therefore, impulse and pressure per step were calculated under different conditions, including flat ground, stairs, and slopes.
Methods
In this study, walking motion was analyzed using SPLYZA Motion (SPLYZA Inc.). First, four male and four female high school students walked back and forth along a flat school corridor, both barefoot and wearing slippers. A stable walking section was selected and analyzed using SPLYZA Motion. The difference between the center-of-mass velocity immediately after toe-off and that immediately before foot contact was calculated (hereafter referred to as DS). Based on this value, the impulse (N·s) was calculated using Equation (1).
Impulse (N·s) = mass (kg) × DS (1)
Next, the same procedure was carried out on a riverside staircase (27°) and on slopes (18° and 28°).
Furthermore, the average pressure exerted on the ground during one step on flat ground, stairs, and slopes was calculated using Equation (2).
Pressure (Pa) = {impulse (N·s) ÷ contact time (s) + mass (kg) × gravitational acceleration (m/s²)} ÷ contact area (m²) (2)
Results and Discussion
The DS values on flat ground ranged from -0.01 to 0.183 m/s. The large variation among participants was likely due to individual differences in walking patterns. DS values on stairs and slopes ranged from 0.107 to 0.208 m/s, which were greater than those observed on flat ground. This may be because walking on stairs and slopes involves a momentary deceleration during each step. Furthermore, DS values during ascent were greater than those during descent. Overall, DS was greatest on stairs, followed by the 28° slope, the 18° slope, and flat ground. This may reflect differences in vertical movement. However, the calculation of the center of mass was unstable, indicating that improvements in the recording method are necessary in future studies.
Next, the average pressure exerted on the ground was calculated from the impulse. As a result, the pressure generated by human walking was approximately 20-40 kPa on flat ground and about 23 kPa on stairs and slopes, showing strong dependence on contact area and body weight. According to Striker et al. (2006), the pressure exerted by the hoof of an adult cow on the ground is approximately 300 kPa. In the grass species Paspalum dilatatum, root tissues are reported to be damaged at pressures above 380 kPa, whereas in the dicotyledonous species Lotus glaber, root tissues are reported to be damaged at pressures above 260 kPa.
The pressure exerted by human walking in this study was lower than these reported thresholds. These results suggest that the impact of a single human step on soil and plants may be limited. However, repeated trampling and cumulative effects should also be considered.
Conclusion
This study demonstrated that SPLYZA Motion can be used to estimate impulse and pressure under different walking conditions. However, to achieve more accurate analyses, it is necessary to further examine factors such as recording methods and measurement environments.
In future work, it will be necessary to clarify how and to what extent a single human step affects the physical properties of trail soil in order to inform the design of erosion-resistant mountain trails. In addition, since trampling by humans occurs repeatedly, evaluations that take walking frequency and cumulative effects into account will also be required.
Deer (Cervus nippon) are known to feed on understory vegetation and, when such vegetation is scarce, on leaf litter. As a result, ground surface cover decreases, leading to deterioration of soil physical properties and increased soil erosion (Onda and Yamamoto, 1998). In Japan, where hiking is popular, human trampling in forested areas has also been reported to negatively affect surface conditions, causing the expansion of bare ground and soil compaction (Takatsuki, 2015). Furthermore, in the Sagano High School Woods for Field Studies, long-term research activities have created trails, and soil erosion has become a serious issue in some areas (Sayama, 2020).
To prevent soil erosion, various measures to reduce human impact can be considered. In order to enhance the sustainability of research activities, it is necessary to examine appropriate trail design.
The objective of this study was to estimate the load exerted on the soil surface by human walking and to examine appropriate walking methods and trail design. Therefore, impulse and pressure per step were calculated under different conditions, including flat ground, stairs, and slopes.
Methods
In this study, walking motion was analyzed using SPLYZA Motion (SPLYZA Inc.). First, four male and four female high school students walked back and forth along a flat school corridor, both barefoot and wearing slippers. A stable walking section was selected and analyzed using SPLYZA Motion. The difference between the center-of-mass velocity immediately after toe-off and that immediately before foot contact was calculated (hereafter referred to as DS). Based on this value, the impulse (N·s) was calculated using Equation (1).
Impulse (N·s) = mass (kg) × DS (1)
Next, the same procedure was carried out on a riverside staircase (27°) and on slopes (18° and 28°).
Furthermore, the average pressure exerted on the ground during one step on flat ground, stairs, and slopes was calculated using Equation (2).
Pressure (Pa) = {impulse (N·s) ÷ contact time (s) + mass (kg) × gravitational acceleration (m/s²)} ÷ contact area (m²) (2)
Results and Discussion
The DS values on flat ground ranged from -0.01 to 0.183 m/s. The large variation among participants was likely due to individual differences in walking patterns. DS values on stairs and slopes ranged from 0.107 to 0.208 m/s, which were greater than those observed on flat ground. This may be because walking on stairs and slopes involves a momentary deceleration during each step. Furthermore, DS values during ascent were greater than those during descent. Overall, DS was greatest on stairs, followed by the 28° slope, the 18° slope, and flat ground. This may reflect differences in vertical movement. However, the calculation of the center of mass was unstable, indicating that improvements in the recording method are necessary in future studies.
Next, the average pressure exerted on the ground was calculated from the impulse. As a result, the pressure generated by human walking was approximately 20-40 kPa on flat ground and about 23 kPa on stairs and slopes, showing strong dependence on contact area and body weight. According to Striker et al. (2006), the pressure exerted by the hoof of an adult cow on the ground is approximately 300 kPa. In the grass species Paspalum dilatatum, root tissues are reported to be damaged at pressures above 380 kPa, whereas in the dicotyledonous species Lotus glaber, root tissues are reported to be damaged at pressures above 260 kPa.
The pressure exerted by human walking in this study was lower than these reported thresholds. These results suggest that the impact of a single human step on soil and plants may be limited. However, repeated trampling and cumulative effects should also be considered.
Conclusion
This study demonstrated that SPLYZA Motion can be used to estimate impulse and pressure under different walking conditions. However, to achieve more accurate analyses, it is necessary to further examine factors such as recording methods and measurement environments.
In future work, it will be necessary to clarify how and to what extent a single human step affects the physical properties of trail soil in order to inform the design of erosion-resistant mountain trails. In addition, since trampling by humans occurs repeatedly, evaluations that take walking frequency and cumulative effects into account will also be required.