Carbon stock dynamics along a cork oak stand chronosequence: implications for climate-smart forest management

Abstract Forests, as carbon sinks, represent a key strategy for mitigating climate change. This study assessed carbon stocks and annual carbon accumulation rates (ACAR) across four reservoirs: aboveground biomass (AB: trees and undergrowth), belowground biomass (BB: roots), necromass N (litter and deadwood) and soil in the Maâmora cork oak ( Quercus suber L.) agro-forest in Morocco, along a chronosequence of six stand age classes (< 10, 10–20, 20–40, 40–80, 80–120, and > 120 years). We hypothesized that stand age would significantly influence Carbon distribution and accumulation dynamics. Allometric equations and specific conversion factors were used to estimate biomass and carbon stocks, while soil carbon was calculated from bulk density, organic carbon concentration, and a sampling depth of 40 cm. Stand age significantly affected both Carbon storage and ACAR in all reservoirs. Total carbon stocks ranged from 49.19 to 231.37 Mg C ha −1 for stands aged < 10 and > 120 years, respectively, with an average of 140.96 Mg C ha −1 . AB, BB, and N Carbon stocks ranged from 8.91 to 105.37, 0.25 to 15.26, and 0.03 to 4.13 Mg C ha⁻ 1 , respectively. Soil remained the dominant reservoir (40–106.61 Mg C ha⁻ 1 ). ACAR decreased with age for AB and soil but increased and then stabilized for BB and N. Mean ACARs were 1.15, 0.13, 0.04, and 3.02 Mg C ha⁻ 1 y⁻ 1 for AB, BB, N, and soil, respectively, with a total average of 4.30 Mg C ha⁻ 1 y⁻ 1 . Strong correlations among reservoirs suggested tightly coupled carbon cycling in cork oak ecosystems. Although focused on Mediterranean stands, the observed patterns may also apply to arid regions with similar conditions. We recommend preserving older stands and promoting age-class diversity to enhance long-term carbon sequestration and support climate-resilient forest management across dryland ecosystems.