Sattar Ezzati,
Akbar Najafi 
,
M. A. Rab,
Eric K. Zenner
Recovery of soil bulk density, porosity and rutting from ground skidding over a 20-year period after timber harvesting in Iran
Ezzati S., Najafi A., Rab M. A., Zenner E. K. (2012). Recovery of soil bulk density, porosity and rutting from ground skidding over a 20-year period after timber harvesting in Iran. Silva Fennica vol. 46 no. 4 article id 908. https://doi.org/10.14214/sf.908
Abstract
Ground-based skidding can have detrimental effects on soil properties trough soil profile disturbance and compaction that can persist for decades. We investigated the recovery of physical properties of disturbed brown soils on four abandoned downhill skid trails in a deciduous mountain forest in northern Iran. The most recent skidding operations had taken place 1–5 yrs, 6–10 yrs, 11–15 yrs, and 16–20 yrs ago, providing a 20-year chronosequence with four 5-year recovery periods. For each recovery period, mean values for soil bulk density (BD), total porosity (TP), macroporosity (MP), soil moisture content (SM), and rut depth (RD) were assessed for three levels of traffic intensity (Primary (PS), Secondary (SS) and Tertiary (TS) skid trails) and two levels of slope gradients (Gentle (G) and Steep (S)) and compared to those in undisturbed (control) areas. Over the 20-year recovery period, PS trails on gentle slopes exhibited mean values that were 35–42% (BD), 3–7% (SM), and 13–19 cm (RD) greater and 18–24% (TP) and 19–28% (MP) lower compared to undisturbed areas; on steep PS trails, values were 40–46% (BD), 2–13% (SM), and 13–21 cm (RD) greater and 23–27% (TP) and 28–35% (MP) lower, respectively. While RD and SM recovered, 20 years was not long enough for the other physical soil properties, particularly on steep slopes. To minimize soil disturbance, skidding should be confined to areas with gentle slopes and alternative harvesting methods such as cable yarding should be used where slope gradients exceed 20%.
Keywords
soil disturbance;
timber harvesting;
soil conservation;
skid trail slope;
mountainous forest
- Ezzati, Department of Forestry and Forest Engineering, Tarbiat Modares University, P.O. Box 64414-356, Iran E-mail se@nn.ir
-
Najafi,
Department of Forestry and Forest Engineering, Tarbiat Modares University, P. Box 64414-356, Iran
E-mail
a.najafi@modares.ac.ir
- Rab, Soil Physics Future Farming Systems Research Division, Department of Primary Industries, Victoria, Australia E-mail mr@nn.ir
- Zenner, Department of Ecosystem Science and Management, Pennsylvania State University, University Park, PA, USA E-mail eric.zenner@psu.edu
Received 21 May 2012 Accepted 10 September 2012 Published 31 December 2012
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