Table 1 Acronym, unit, and description of respiration rates (R) and CO₂ and water fluxes (F)

Root respiration

mmol day⁻¹ stem⁻¹

R _R

Root-respired CO₂ through xylem

mmol day⁻¹ stem⁻¹

F _T

Sap flux

L day⁻¹ stem⁻¹

F _H2O

Dissolved CO₂ at stem base

mmol L⁻¹

[CO₂ ^*]_base

Soil CO₂ efflux

μmol s⁻¹ m⁻²

F _S

Soil CO₂ efflux at 16 °C

μmol s⁻¹ m⁻²

F _S16

Heterotrophic respiration in soil at 16 °C

μmol s⁻¹ m⁻²

R _H16

Litter respiration at 16 °C

μmol s⁻¹ m⁻²

R _L16

Root-respired CO₂ through soil at 16 °C

mmol day⁻¹ stem⁻¹

F _S16-root