Effect of alder plantation age on soil carbon sequestration

There had been no study about the effect of the plantations’ age on the properties of forest soils and soil carbon sequestration. Therefore, the aim of this study was to investigate the effect of an alder plantation’s age on some soil properties and carbon sequestration. Three alder plantation stands (25, 30, and 35 years old) located in Parcels No. 6 and 7 in Shastkolateh forest were selected. In order to investigate the quantitative characteristics of trees, the diameter and height of all trees were recorded using the full inventory method. In each stand, 20 × 20 m sample plots were considered using a systematic random method with a 50 × 50 m grid. A soil sample was then taken at the depth of 0-15 cm in each plot using the core method. The result showed that the 35-year-old stand had the highest soil moisture (45.49%±2.44) and the lowest bulk density (1.36 g/cm2±0.02). The highest pH (7.59 ±0.01) and the lowest EC (0.71±0.02 dS/m) were observed in the 35-year-old stand. The highest and lowest percentages of total soil nitrogen as well as carbon sequestration were observed in the 35- and 25- year- old stands, respectively. The results of component analysis showed that the 35-year-old stand was different from the other two stands; hence, it can be stated that alder plantation stands will have a high capacity for carbon sequestration at this age.