Changes of some soil components under the influence of thinning intensity in Marivan forests

Soil and vegetation are mutually influencing because of strong bilateral relations. Soil characteristics can be different depending on the density of vegetation and the type of land use. Since the long-term stability of forest ecosystems is dependent on maintaining the quality of the soil, knowing the condition of the soil in forest areas and investigating the effects of various activities on the soil properties is very important and effective in forest management. Therefore, in this research, we investigated and studied the effects of intensive Thinning operations on some soil components in a Coppice stand and young Sprout-Clumps of Quercus brantii Lindl. species in Rikhlan forest (a forest site in Marivan). This area is an indicator of the degraded forests of North Zagros. this research was conducted in the form of complete randomized blocks in three treatments and three repetitions. The duration of the research was 8 years in two phases of 4 years. In addition to thinning treatments, soil samples were also prepared and analyzed from a depth of 0-15 cm of each treatment. The general conclusion is that thinning operations have long-term effects on some soil indices, and thinning with increasing intensity (18% of all Sprouts removed in the first 4 years and 22% of remaining Sprouts in the next 4 years) compared to thinning with The reducing intensity (32% of all Sprouts removed in the first 4 years and 28% of remaining Sprouts in the next 4 years) has caused the least stress on soil fertility indicators.