Resprouting shrubs significantly contribute to Mediterranean forest carbon stocks with their root system
摘要
Shrubs constitute an important, yet often underestimated component of forest ecosystem carbon stocks, particularly in Mediterranean regions. Resprouting shrub species further strengthen this role through substantial belowground carbon reserves, a mechanism that remains insufficiently investigated. This study investigated shrub biomass and carbon storage in two contrasting stand ages, a young site (YS) and aged site (AS) of a Quercus suber (cork oak) forest in northwestern Tunisia. Species-specific allometric equations were developed for dominant shrubs (Pistacia lentiscus, Myrtus communis, Erica arborea) to estimate aboveground (AGB), belowground (BGB) and total biomass using dendrometric variables (height, basal diameter, crown diameters). Nonlinear models provided the best predictive accuracy. Biomass and carbon stocks increased significantly with stand age. Total shrub biomass was 9.12 Mg ha−1 (4.96 Mg C ha−1) in YS and 32.55 Mg ha−1 (19.15 Mg C ha−1) in AS, with 1.6% in belowground compartment of total forest biomass for YS and 6.0% for AS. Litter carbon storage was higher in AS (5.05 Mg C ha−1) than YS (3.96 Mg C ha−1), while soil organic carbon (SOC) stocks were substantial with 302.61 and 457.77 Mg C ha−1 in YS and AS, respectively. These findings highlight the significant carbon sequestration potential of resprouting shrubs in Mediterranean forests.