Some aspects of the turbulence kinetic energy and fluxes above and beneath a tall open pine forest canopy

In addition, we evaluate the spatial heterogeneity of the TKE, the three TKE tendency terms, the CO2 flux, moisture flux, heat flux and the friction velocity in the subcanopy. In terms of fluxes, the heterogeneity is by far the largest for the CO2 flux. Based on the observed weak heterogeneity of the turbulence and the strong heterogeneity of the CO2 flux, we conclude that significant variations in the CO2 source terms occur on scales smaller than our network, where the distance between measurement sites is 87 m. We also observe large systematic differences in the long-term average subcanopy moisture and especially CO2 flux depending on location within the network of measurement sites despite the lack of any clear differences in soils, exposure, vegetation, elevation or terrain slope.