Daytime surface sensible and latent heat fluxes were estimated above boreal forest from the boundary layer budgets of heat and water vapor. Two budgets were integrated from serial soundings in the atmospheric boundary layer: one for the mixed layer and one for the entrainment layer. Horizontal and vertical advection were derived from synoptic analyses. The surface fluxes were then calculated as a budget residual. The mean entrainment parameter AR above the boreal forest was estimated to be 0.21. The dependence of entrainment on buoyant and shear forcings agreed with earlier studies. ¿ 1997 American Geophysical Union