Embracing fine-root system complexity in terrestrial ecosystem modeling

Area of Science:

• Ecology
• Ecosystem Modeling
• Biogeochemistry

Background:

• Ecosystem models have historically neglected fine-root system complexity.
• Recent advances highlight functional differentiation in fine roots and mycorrhizal associations.
• This gap limits accurate biosphere dynamics and carbon cycling projections.

Purpose of the Study:

• To introduce a novel three-pool structure, Transport and Absorptive roots with Mycorrhizal fungi (TAM), for modeling fine-root systems.
• To bridge the data-model gap by incorporating fine-root complexity into ecosystem models.
• To improve the accuracy of biosphere and carbon cycle projections.

Main Methods:

• Developed a three-pool model (TAM) representing transport roots, absorptive roots, and mycorrhizal fungi.
• Integrated the TAM model into a big-leaf ecosystem model.
• Demonstrated the model's proof-of-concept in simulating carbon cycling in temperate forests.

Main Results:

• The TAM model provides a vertically resolved representation of fine-root systems.
• Simulations showed significant impacts of fine-root differentiation on carbon cycling.
• The model balances realism and simplicity, offering an effective approximation.

Conclusions:

• The TAM framework offers a more realistic and efficient approach to modeling fine-root dynamics.
• This approach can help reduce uncertainties in biosphere and carbon cycle modeling.
• TAM provides a unified framework for modelers and empiricists to collaborate on ecosystem complexity.