IMPACT OF CEDRUS LIBANI AFFORESTATION ON SOIL CARBON AND NITROGEN STOCKS IN THE UPPER MEDITERRANEAN BASIN

Soils, as the most dynamic and complex components of terrestrial ecosystems, serve as crucial sinks for atmospheric carbon storage and retention. Human interventions in soil management significantly influence the amount of carbon and nitrogen stored or sequestered. This study investigated the effects of afforestation using Cedrus libani A. Rich (Lebanese cedar or Taurus cedar) at two different ages (10 and 25 years) in the Upper Mediterranean basin on soil organic carbon and nitrogen stocks. The afforestation was conducted on previously bare lands for soil conservation purposes. A total of 45 soil samples were collected from topsoil (0–10 cm): 15 samples were randomly taken from two different times (2000 and 2015) afforested areas and 15 from non-afforested (control) land. Soil organic carbon (SOC), total nitrogen (TN), and bulk density (BD) analyses were performed on these samples. To calculate soil organic carbon stocks in tons per hectare, bulk density (BD) was estimated using the SOC and soil mass equation. The results revealed a substantial increase in carbon and nitrogen storage in the afforested areas, depending on tree age. Specifically, organic carbon and nitrogen stocks in the topsoil of 25-year-old and 10-year-old afforestation sites were 65% and 48% higher, respectively, than in control soils. Carbon and nitrogen storage followed the trend: 25-year > 10-year > 0-control. The highest total nitrogen content (0.78%) was observed in 10-year-old cedar afforestation sites. While BD values did not differ significantly among afforested areas, the control areas showed distinct differences from the afforested sites. This study demonstrates that age-protected cedar afforestation significantly enhances carbon and nitrogen sequestration in previously bare soils, highlighting its importance for soil conservation and ecosystem sustainability.