A method is described for determining water consumption of trees by transpiration considering the ecoclimatic factors of the environment. The trees are studied in a situation where they have accenss to as much water as they need. The tree species being studied are transplanted to large plastic containers in which, by means of special system, the subsurface water is maintained at a constant level. Whenever there is a decrease in the level of surface water, the special mechanism, which registers accumulated water in the study system, automatically restores the water to its initial level by the addition of more waterSe describe un método para determinar el consumo de agua por transpiración de árboles en relación a los factores ecoclimáticos que los rodean, en el supuesto caso que el suelo que los sustenta posee toda el agua requerida por ellos. Para tal finalidad se transplantan los árboles en estudio a grandes recipientes plásticos. A pocos centímetros del fondo de estos recipientes, y mediante un mecanismo especial, se mantiene constante la altura del nivel de una napa freática artificial. Toda el agua requerida para mantener la altura de este nivel, que sólo pudo haber descendido por consumos de evapotranspiración, es registrada en un medidor.