Carbon (C) sequestration refers to the transfer of atmospheric CO₂ into long-lived global (C) stocks including oceanic, pedologic (soil), biotic, and geological strata so that it is not re-emitted into the atmosphere within a time frame of years to millennia (Bruce et al., 1999; Lal, 2008). Carbon sequestration has a strong impact on the global C cycle as it reduces the amount of carbon dioxide in the atmosphere resulting in the mitigation of global climate change (Hui et al., 2020). The process of CO₂ sequestration into terrestrial ecosystems is based on the natural process of photosynthesis and involves the adoption of land use and soil/vegetation management systems which enhance net primary production (NPP), and transfer some of the photosynthates (through return of biomass) into soil organic carbon (SOC) as stable humic substances with long residence time. There are two distinct but related components of terrestrial sequestration: vegetation (especially trees) and soils. This study offers important insights in comparing the soil carbon stocks of planted forests and nearby natural unplanted woodland along an aridity gradient in Israel.

Drylands are drought areas where rainfall is erratic and below-average than the potential moisture losses through evaporation and transpiration (Sharma et al., 2012). The world’s drylands cover 41–47% of the terrestrial surface (Christensen et al., 2007) and soils contain 241 Pg of soil organic carbon (SOC) that comprise 27% of the global soil organic carbon (SOC) stock (Christensen et al., 2007; Lal, 2004). Management of SOC stocks in dryland ecosystems can play a major role in reducing atmospheric CO₂ (Lal, 2002). Although, environmental degradation and desertification are pervasive in these regions resulting in emissions of CO₂ into the atmosphere and leading to dramatic reductions in the SOC stock (Sharma et al., 2012). Afforestation often results in increased ecosystem-scale C stocks, mainly because of the build-up of aboveground tree biomass (De La Maza et al., 2009). Woody vegetation into deserts and grasslands, resulted in a reduction of SOC at moist sites but increased SOC stocks at dry sites as a lack of water limits soil mineralization and therefore the flux of C to the atmosphere (Sharma et al., 2012; Smith & Johnson, 2003). Thus, dry areas appear to have a potential for net C sequestration in soils following a few decades of the establishment of woody vegetation, C stocks in a semi-arid plantation of Aleppo pine (PinushalepensisMill) in Israel showed that both ecosystem and SOC stock were increased by afforestation of former shrubland (Grünzweig et al., 2003). Therefore, sequestration of atmospheric C in the soil and biomass not only reduces the greenhouse effect but also helps maintain or restore the capacity of the soil to perform its production and environmental functions on a sustainable basis.