Effect of Skidding Operation on Organic Carbon of Forest Soil

According to the importance of soil in forest ecosystem, this study was conducted in Mazandaran Province of Iran to investigate the effects of skidding operation on organic carbon of soil. Therefore, the objective of this research was to compare the rate of soil organic carbon between two areas inside and outside of the skid trails based on its depth. In order to carrying out of field survey, two samples from inside (for different depth of 0-5 and 5-10 centimeters) and two samples from outside of each 20 meters of skid trail were taken (Totally 80 soil sample). The rate of organic carbon was determined with burning through black&walking method. Results show that in all stations the percentage of organic carbon in soil samples collected from outside of trails was more than that of soil samples collected from inside of skid trail. Result of statistical analysis show that the skidding causes to significant difference between the two treatments for percentage of organic carbon (inside and outside of skid trail) in different depth of soil (P<0.05). Moreover, changes in percentage of soil organic carbon in samples measured for inside of skid trail was high and for outside of skid trail was low. The mean of soil organic carbon in layer of 0-5 centimeter was more than that of the layer of 5-10 centimeter. But, this difference is not significant (P<0.05). In order to decrease damage to forest soil it is better that the skid trail is covered by vegetation foliage and wood debris. Moreover, it is recommended that the skid trails seeded after skidding operation. Moreover, in order to decrease disturbance of soil organic matter in forest ecosystem, Tite Pressure Control System (TPCS) can be used on skidders to reduce the pressure of wheels per unit area at minimum level.