Carbon Sequestration Enhancement by Irrigation in a Mediterranean Pine Forest

Area of Science:

• Forestry
• Ecology
• Climate Science

Background:

• Mediterranean drylands, particularly semi-arid forests like Aleppo Pine (Pinus halepensis), play a role in atmospheric carbon dioxide (CO2) sequestration.
• Understanding carbon sequestration dynamics in these regions is crucial for climate change mitigation strategies.
• Water availability is a key limiting factor for forest productivity and carbon uptake in arid and semi-arid environments.

Purpose of the Study:

• To quantify organic and inorganic carbon sequestration in a Mediterranean semi-arid Aleppo Pine forest.
• To differentiate the impacts of soil water stress versus atmospheric water demand on CO2 sequestration.
• To assess the effect of long-term irrigation on carbon sequestration rates.

Main Methods:

• Field measurements utilizing gas exchange techniques.
• Stock counting approach for biomass and soil carbon assessment.
• Remote sensing technologies for broader spatial analysis.
• Comparison between rainfed control plots and long-term drip-irrigated plots.

Main Results:

• Organic carbon sequestration (OCS) measured at approximately 550 g CO2 m⁻² yr⁻¹, with 60% in soil and 40% in biomass.
• Inorganic carbon sequestration (ICS) measured at approximately 65 g CO2 m⁻² yr⁻¹ (0.5m soil depth) through calcite precipitation.
• Drip-irrigated plots exhibited ~3 times higher OCS and ~1.8 times higher ICS compared to control plots.
• Irrigation effects were equally distributed between soil and biomass for OCS.

Conclusions:

• Mediterranean dryland forests possess a substantial capacity for carbon sequestration.
• Irrigation significantly enhances both organic and inorganic carbon sequestration in Aleppo Pine forests.
• Forest management strategies, including irrigation, can optimize carbon sequestration potential in water-limited ecosystems.