saeedeh joriz; Meghdad Jourgholami; arash malekian; maryam etehadi
Abstract
Land use changes can significantly affect the hydrology of a forest watershed. Ground cover is important to protect the soil against erosion. Timber harvesting has been changed the canopy cover and forest soil was exposed to the wind and water. Soil compaction and removing the forest floor in the skid ...
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Land use changes can significantly affect the hydrology of a forest watershed. Ground cover is important to protect the soil against erosion. Timber harvesting has been changed the canopy cover and forest soil was exposed to the wind and water. Soil compaction and removing the forest floor in the skid trails was reduced the capacity of water absorption in mineral soils and thus reduced water infiltration, increased runoff, which caused to soil erosion. In order to measure the rate of sediments in two slopes and to study the effect of skid trails on the amount of sediments, the plot-level study was carried out in the Gorazbon district in Kheyrud forest in the control area and skid trail after skidding operations in the sample plot. The results showed that the most sediment value was 1.938 g. liter-1 in the skid trail with a 20-40 percent slope in the autumn and the lowest deposition was 0.103 g. liter-1 in the control area with a slope of 20-40 percent in the autumn. Type of Coverage (skid trail and control area), the season and the interactions between the cover and the season statistically have significant effect on the sediment yield, but the slope and the interactions between the slope and cover, as well as the interactions between the slope and season have no statistically significant effect on the sediment yield. Duncan’s test showed that there was a yield statistically significant difference between sediment yeild in different seasons and the autumn had the highest sediment
maryam etehadi abari; a a; a a; meghdad jur gholami
Abstract
Land cover is also important factor for protecting the soil against erosion. A fully forested watershed experiences relatively little surface erosion, but timber harvest alters the canopy cover, exposing the soil to water and wind. Forests provide the maximum amount of soil protection. Reduction of vegetative ...
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Land cover is also important factor for protecting the soil against erosion. A fully forested watershed experiences relatively little surface erosion, but timber harvest alters the canopy cover, exposing the soil to water and wind. Forests provide the maximum amount of soil protection. Reduction of vegetative cover by forest harvesting generally increases the average surface runoff volume and sediment While, the hydrologic response of forest harvesting has been rarely considered. Towards this attempt, the present study has been conducted to investigate the effect of vegetation cover on hydrological components in plot scale (2m*1m) with four replicates in tow slope scale (0-20%, 20-40%) in Kheyrud Forest of Iran during December 2014 until December 2015. The rain depth was measured by using a rain gauge installed in the study area. The runoff volume and sediment yield were also measured through field data collection and lab analyses by weighting and decantation methods. The results of the study showed significant effects of vegetation cover (P ≤0.01) on runoff volume and sediment yield. Natural forest without harvesting, forest with selective harvesting treatments exhibited the lowest amounts of runoff and sediments, with averages of 372.31, 878.96 cc, and 0.08, 0.17 gr m-2 respectively, in comparison to other treatments. Linear regression among mentioned parameters (precipitation, runoff, and sediment) were determined. The results show that there were significant correlation and linear regression among precipitation, runoff and sediment.