Recovery of disturbed soil organic matter over a 10-year period after timber skidding operation in forest

Logging operation due to soil disturbance and compaction changes soil physical and chemical properties. On the other hand، there is a paucity of data on the time required for recovery of disturbed soil properties. This research was therefore carried out to investigate the effects of ground-based skidding on organic matter، which is one of the important chemical soil properties، and it''s process of recovery over a period of 10 years after timber skidding. Changes in organic matter was quantified at three traffic levels including low، medium and heavy on a skid trail that has recently been established. Three skid trails have been left without skidding and traffic for one، five and ten years. The results indicate that skidding with regard to traffic intensity، when compared with the control، significantly decreased organic matter by 32. 5، 53. 5 and 58. 5% at low، medium and heavy traffic، respectively.. Furthermore، the rate of recovery with regard to traffic intensity varied depending on degree of soil disturbance، where low traffic showed more recovery than medium and heavy traffic. The results revealed that soil organic matter removal by skidding was beyond the disturbance threshold and even after a ten-year period، no complete recovery was observed.