Abstract: Canopy conductance is a key ecological parameter characterizing gas exchange process between plants and the atmosphere, playing a crucial role in regulating material and energy balance of terrestrial ecosystems. Under the context of global change, canopy conductance, as a core regulatory factor in the carbon-water coupled cycle, holds important scientific value for clarifying the adaptive mechanisms of forest canopy in response to climate change. We reviewed the response characteristics of forest canopy conductance to environmental factors such as photosynthetic radiation, temperature, air humidity, and CO₂ concentration, and then explored the mechanisms by which stomatal behaviors regulate plant growth and physiological processes. We further evaluated the applicability of existing forest canopy conductance calculation methods including the Penman-Monteith equation, up-scaling approaches, and remote sensing techniques. Despite the significant progress in these calculation methods in recent years, limitations remain in terms of their applicability under extreme climate conditions and universality across different developmental stages of forests. Future research should focus on the dynamic stress mechanisms of extreme climate events on canopy conductance and the effects of stand age. By integrating multi-source remote sensing data and optimizing the parameter scheme with the process-based models, a cross-scale canopy conductance simulation framework can be constructed. This review provides theoretical support for improving the carbon-water coupled cycle simulation framework and offers scientific evidence for forest management strategies under climate change.

Key words: canopy conductance, carbon and water coupling, process-based modeling