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Abstract This paper analyses the evolution of high flows in the Central Spanish Pyrenees during the period 1955-1995. The method applied makes it possible to assess whether the contribution of the largest daily discharge and rainfall events to the total annual runoff and precipitation remains stationary or shows any temporal trend. The results show a general negative trend in flood intensity in the last decades, together with an increase in the importance of low flows in the total annual contribution. However, a change in the frequency distribution of precipitation events has not been detected. The different behaviour shown by runoff and precipitation could only be explained as being due to the increase in plant cover that is a consequence of the farmland abandonment and reforestation that occurred during the 20th century. Key words: high flows; trend analysis; plant recolonisation; Central Spanish Pyrenees. Tendances aux crues dans les Pyrénées Centrales espagnoles: réponse aux facteurs climatiques ou à l´aménagement du territoire? Résumé Ce travail analyse l´évolution des crues dans les Pyrénées Centrales espagnoles pendant la période 1955-1995. La méthode appliquée tente de déterminer si l