Mechanistically-grounded pathways connect remotely sensed canopy structure to soil respiration

Area of Science:

• Ecology
• Remote Sensing
• Forest Science

Background:

• Soil respiration (Rs) is a major component of the soil-to-atmosphere carbon flux, influenced by biotic and abiotic factors.
• Established drivers of Rs include soil temperature, moisture, and root biomass.
• The link between canopy structure and Rs via these drivers remains unclear.

Purpose of the Study:

• To assess the relationship between above- and belowground vegetation structure and soil respiration.
• To determine if remotely sensed canopy structure can predict Rs through mediated pathways.
• To investigate the role of canopy complexity and density in regulating Rs.

Main Methods:

• Utilized light detection and ranging (lidar) to derive measures of canopy structure (rugosity, vegetation area index).
• Assessed relationships between canopy structure metrics and soil respiration at the stand-scale.
• Examined the influence of canopy structure on light interception, soil microclimate, and fine root mass density.

Main Results:

• Canopy rugosity (complexity) and vegetation area index were coupled to soil respiration.
• Canopy complexity showed a stronger link to Rs than vegetation area index.
• Canopy and root complexity were not spatially coupled, with canopy complexity increasing during stand development.

Conclusions:

• Remotely sensed canopy complexity can infer spatial variation in soil respiration.
• The relationship between canopy complexity and Rs is supported by mechanistic pathways involving light, microclimate, and root density.
• Future research should integrate multi-site observations of canopy structure and Rs using open data platforms.