The effect of distance and decay class of Oak deadtrees on some soil properties in Siahkal forests, Guilan

In order to study the effect of distance and decay class of Oak (Quercus castaneifolia) fallen deadtrees on some chemical properties of soil, parcel 238 with an area of 37 hectares from district 2 of Siahkal forests, Guilan, Iran was selected. Total of 32 deadtrees from oak species were identified and surveyed. Regarding to four decay classes, three oak deadtrees in each class (12 specimens) were randomly selected. Then the length of each deadtree was divided into four equal parts and a soil sample was taken from each part in depth of 0- 20 where they mixed together as a soil sample of each deadtree. The results of data analysis indicated that soil nitrogen of deadtrees with decay class 4 was significantly different from others and its transfer rate increased with increasing of decay classes. Moreover, organic carbon, potassium, and phosphorus amounts were higher in the soil under deadtrees and decreased with increasing distance of them. The highest amount of soil phosphorus and potassium belonged to deadtrees with decay class 1, and soil organic carbon increased with increasing deadtrees decay degree. However, there was no significant difference in soil acidity of deadtrees with different decay class and distance. Therefore, the Findings of the current research illustrated that the properties of soil could be changed based on decay class and distance, and due to the increasing and decreasing trend of soil parameters over time, deadtrees with different decay classes are essential and should be considered in forest management.