Determination of carbon and nitrogen storage in belowground biomass of pure red pine (Pinus brutia Ten.) stands in the Muğla-Kavaklıdere region and some factors effecting them

This study investigated the effects of aspect, site index, and stand development stage on aboveground stock, litter amount, and stored carbon and nitrogen contents, belowground root mass and stored carbon and nitrogen contents, and some physical and chemical soil properties of pure red pine (Çz) natural stands located in Kavaklıdere district of Muğla province. Within this scope, a total of 112 trial plots were selected within the boundaries of Kavaklıdere Forest Management Directorate, taking into account aspect, site area, and stand development stages. Studies were conducted in these trial plots. In these selected trial plots, stock was calculated by measuring diameter, height, and age. Root stock and stored carbon and nitrogen contents were determined by belowground root sampling. Litter sampling was conducted to determine the carbon and nitrogen contents stored in the litter. Furthermore, disturbed and undisturbed soil samples were taken at different depths and some soil analyses were conducted. Correlation analysis and analysis of variance were used to determine the relationships between the obtained variables. As a result of the study, the amount of biomass in pure red pine stands was determined as 236, 209 and 217 m3/ha in the 1st, 2nd and 3rd sites, respectively. In terms of stand types, the highest biomass content was found in the Çzd3 stand. The biomass content in the sunny aspect was higher than the shady aspect. The maximum amount of belowground root capillary roots was calculated as 8.73 tonnes/ha in the 1st site, and the amount of carbon stored was calculated as 2.74 tonnes/ha. Thick root values were calculated as 12.01 tonnes/ha, while the stored carbon value was calculated as 4.35 tonnes/ha. The maximum biomass content was calculated as 45.9 tonnes/ha in the 1st site, and the stored carbon was calculated as 12.8 tonnes/ha. The amount of nitrogen stored in the biomass was measured as 0.36 tonnes/ha. In general, the effect of the site on biomass, biomass and root values was found to be statistically significant. Areas with good soil properties were found to be more productive. The effect of aspect and stand development stage was not significant. The soils in the study area were classified as neutral in pH, salt-free in EC, rich in skeletal content, and poor in organic matter and nitrogen. The arid climate and the highly stony soil structure were also found to have limiting effects on the parameters measured in the study area.