Carbon dioxide sequestration capability of an unmanaged old-growth broadleaf deciduous forest in a Strict Nature Reserve

ABSTRACT

The seasonal trend of plant carbon dioxide (CO₂) sequestration is related to the photosynthetic activity, which in turn changes in response to environmental conditions. Great interest has turned to the CO₂ sequestration (CS) potential of temperate forests which play an important role in global carbon (C) cycle contributing to the lowering of atmospheric CO₂ concentration. In such context, the CS of an unmanaged old broad-leaf deciduous forest developing inside a Strict Nature Reserve, and its variations during the year were analyzed considering the monthly variations of leaf area index (LAI) and net photosynthetic rates (N_P). Overall, the total yearly CS of the forest was 141 Mg CO₂ ha⁻¹ year⁻¹ with the highest CS value monitored in June (405 Mg CO₂ month⁻¹) due to the highest LAI (5.0 ± 0.8 m² m⁻²) and a high N_P in all the broadleaf species. The first CS decline was observed in August due to the more stressful climatic conditions that constrained N_P rates. Overall, the total CS of the forest reflects the good ecological health of the ecosystem due to its conservative management.

KEYWORDS:

• Carbon dioxide sequestration
• leaf area index
• net photosynthetic rates
• deciduous forest
• unmanaged forest

Acknowledgments

This work was supported by the “Natural Reserve Bosco Siro Negri” funded by the Ministry of the Environmental and Protection of land and Sea of Italy. We acknowledge two anonymous reviewers for their comments having contributed to improve the manuscript.