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The properties of litter and soil, which are probably influenced by vegetation traits, have an effect on the fractions of C and N and ultimately global warming. In this study, litter and soil samples were collected from representative forestlands, including a mixed natural forest dominated by hornbeam-ironwood and tree plantations of ash, maple, cypress and pine which are situated in a temperate area of Northern Iran. Main litter characteristics, soil aggregation and fractions of C and N were studied. Pine had the highest values of litter thickness (14.46 cm), C (60.31%) and C/N ratio (81.77 and 20.28 for litter and soil, respectively). However, litter N (2.20%), micro aggregates of total soil (39.75%), aggregate stability (73.86%) and macro aggregates of total soil (54.87%) were found significantly higher under the natural stands. Total C (2.58%), C in macro and micro aggregates (0.31 and 0.33 respectively), POM-C (4. 68 g/kg), DOC (125.54 mg/kg) and C sequestration (45.34 Mg/ha) were considerably higher under pine (for POM-C, pine approximate to cypress) and the greater values of total N (0.34%), N in macro and micro aggregates (0.10 and 0.08 respectively), POM-N (0.47 g/kg), DON (33.80 mg/kg) and N sequestration (6.86 Mg/ha) were observed under natural stands. Under our conditions, conversion of natural forest is due to reduction of soil N fractions and C increased under pine tree plantations.