Urban tree channeling of soil methane and nitrous oxide and its mitigation using biochar

Leaf functional traits—such as specific leaf area (SLA) and optical indices (chlorophyll, flavonoids, anthocyanins, and nitrogen balance index [NBI])—are included to assess relationships between leaf structure, physiology, and trace-gas exchange. Tree-level structural and health metrics (e.g., DBH, height, crown dimensions, dieback, chlorosis, and crown transparency) provide context for evaluating how tree size, vigor, and canopy architecture influence foliar and soil greenhouse gas dynamics.

Spatial coordinates (x, y), planting year, mulch cover, and treatment information allow analyses of management history, spatial variability, and urban site effects. Together, these data support investigations of urban carbon and nitrogen cycling, species- and trait-based controls on greenhouse gas fluxes, and the role of urban green infrastructure in climate mitigation and ecosystem modeling.