Evaluation of Changes in Soil Characteristics in the Canopy and Crowns of Pure and Mixed Beech Forests in Shast Kalate

Background: The creation of sequence mosaics in the forest ecosystem, which begins with the regeneration of life in the canopy, has a significant role in the spatial structure of forest masses and can also provide the possibility of establishment of regeneration by changing the characteristics of the soil.However, this relationship is two-way and awareness of it can be effective in the better understanding of natural processes.Therefore, this research generally aims to investigate and compare soil properties in the canopy and closed canopy of pure and mixed beech stands.Hyrcanian forests host critical habitats of oriental beech.Canopy gaps drive ecological succession by altering soil biogeochemistry.This study investigates variations of soil properties in pure vs. mixed beech stands.This study was conducted to evaluate changes in soil physical and chemical properties in open gaps and gaps under the canopy of pure and mixed beech stands in a series of sixty plots.Objectives: 1) Measuring changes in pH, organic carbon, total nitrogen, phosphorus, and available potassium; 2) analyzing the interaction between forest stands and sampling location; and 3) providing management strategies based on the findings.Methods: The chemical changes in the soil layers of the canopy in the pure and mixed masses of beech were investigated by choosing seven sample plots of 25 hectares (500 500 m) inside the parcels 4, 5, 7, 15, 16, 17, and 18 of the series 1 sixty cleats, which were the same in terms of location.After selecting sample pieces, eight canopy and eight closed crowns in pure and mixed beech masses were selected for soil sampling.Soil was sampled from two depths of 0-10 and 10-20 cm using a metal cylinder (diameter 8 cm).The average depth of the organic layer was measured before taking the soil samples, and litter was collected at the site of each sample on a surface measuring 20 20 cm.The chemical properties of the soil, including acidity, organic carbon, nitrogen, absorbable phosphorus, and absorbable potassium, were measured after transferring the soil to the laboratory.The parameters were measured according to ISO and Olsen standards.Two-way ANOVA and Tukey's test (SPSS v26) were used for statistical analyses.Results: The soil properties, including acidity, total nitrogen, and absorbable potassium, at each of the two depths in different positions of the canopy between the pure and mixed masses showed significant differences, and the depth of the organic layer in the pure mass was significantly different in the openings of the canopy less than those of the closed canopy.Among the investigated variables in the organic layer, none of the measured properties, such as acidity, organic carbon, total nitrogen, and absorbable phosphorus and potassium, were significant in different situations of the canopy.The total nitrogen content in the mixed stand was 32% higher than the pure stand, the total nitrogen in the 0-10 cm depth of the mixed stand (0. 28% 0.03) was significantly higher than the pure stand (0.19% 0.02), and the potassium in the pure stand was 33% higher.The absorbable potassium in the 10-20 cm depth of the pure stand (180 ppm 15) compared to the mixed stand (135 ppm 12) showed a 33% increase.There was a 37% decrease in the thickness of the organic layer, and the thickness of the organic layer in the open spaces of the pure stand (3.2 cm 0.4) was 37% lower than the under canopy (5.1 cm 0.6).A phosphorus increase of 20% was seen in the gaps under the open canopy.The concentration of absorbable phosphorus in the open spaces of the mixed stand was 20% higher than in the undercanopy areas.Conclusion: Over time, canopy lighting creates significant changes in the light and microclimate conditions of the forest floor and changes the soil properties and the cycle of nutrients in the forest soil.The formation of a canopy increases both the complexity of the canopy and the diversity in the availability and cycle of the main nutrient elements in the soil, such as nitrogen, phosphorus,