Spatial variability of turbulent fluxes in the roughness sublayer of an even-aged pine forest - Katul, G.; Hsieh, C.-I.; Bowling, D.; Clark, K.; Shurpali, N.; Turnipseed, A.; Albertson, J.; Tu, K.; Hollinger, D.; Evans, B.; Offerle, B.; Anderson, D.; et al. (Boundary-Layer Meteorology, 1999)