Visual assessment of soil disturbance causing forest operation by short wood and full tree methods in western plantations of Guilan

Several methods have been proposed to evaluate soil quality in line with its management and provide suitable management solutions. Visual assessment method of soil disturbance provides a quick and effective tool for cheap evaluation of the quality of the soil in the field. The method of visual evaluation of soil degradation provides a quick and effective tool for cheap evaluation of soil quality in the field. The aim of this study was to visually assessment of soil disturbance due to forest operation by short wood and full tree methods in western plantations of Guilan province. For this purpose, 625 plots were measured in each method based on visual soil assessment method. The results showed that the studied operation methods destroyed different proportions of field areas so that 79.36 and 69.92% of the total area were destroyed in the short wood and full tree methods, respectively. Logging residuals in short wood method was more than in full tree method. The results showed that soil compaction in the short wood method (18.72%) was higher than in full tree method (14.08%). Logging residuals, shallow disturbance and soil compaction were the most common types of soil disturbance cause by logging methods, therefore the highest amount of disturbance in both methods was related to the logging residuals class. The results of Mann-Whitney U test showed that there was a significant difference between the two forest logging methods. In general, the results showed that the type of timber removal method in logging operations and skidding has a significant effect on forest soil disturbance.