Nutrient Dynamics and Decomposition rate of Norway Spruce Needles in Stråsan and Lajim stands

     Climate changes due to changes in a habitat leads to differences in the rate of decomposition and nutrient dynamics of leaflitters, which has many effects on the controlling factors of the decomposition process. In the present study, the rate of decomposition and nutrient dynamics of Norway spruce was evaluated for 363 days in the two forestation sites in the natural and foreign habitats, Stråsan and Lajim. Nutrients such as nitrogen, phosphorus, potassium, calcium, magnesium, manganese and lignin, as well as Limit value, constant coefficient of decomposition and production capacity of humus were investigated using standard methods in both habitats. Nutrient and lignin concentrations were measured individually in each country using the same measurement methods. The results showed that the initial quality of needles, except for calcium and manganese, in Lajim habitat (the concentrations of nutrients in nitrogen, phosphorus, potassium and magnesium were 12.63, 1.23, 9.85, and 1.51 mg/g) was better than Stråsan (the concentrations of calcium and manganese were 13.4 and 1.38 mg/g). The dynamics pattern of nutrients in two habitats was similar during the study period, but in 363 day, there were significant differences (p <0.05) in the concentrations of manganese and phosphorus. The remaining weight in two habitats at the end of the period did not show any significant difference (Lajim and Stråsan habitats were 77.69% and 77.92% respectively). The constant coefficient of decomposition and production capacity of humus in Lajim habitat was higher (respectively, 0.24% per day and 66 fractions) than Stråsan habitat (respectively, 0.1% per day and 55 fractions). Based on the stepwise regression, in the Lajim habitat the concentrations of phosphorus and manganese and in the Stråsan the concentrations of lignin, magnesium and calcium were the only variables which explained mass loss var­iation. In general, the results of this study showed that Norway spruce in Lajim habitat was successful in the view point of the decomposition and nutrient dynamism and in the compared to its natural habitat, and could be used in the Hyrcanian mountain forest for reforestation projects.