Analysts about the relationship between sensible heat and water vapor fluxes and their respectives gradients of temperature ans specific humidity, observed above forest, is developed for, atmospheric instability conditions, these parametrized by Monin-Obukhou's stability lenght, L. The relations flux-gradients are represented by dimensionless functions, which have how independent variable the ratio associated to the observation level, above the referencial plan, (z-d/)L. The integrals of these function, appropriated to the forest evaporation studies, are. also developed. The informations were collected during intensive work of "Amazonian Micrometeorological Experiment", in september-october 19S3 and July-August 1984, in the Reserva Florestal Ducke, Manaus/AM.