Approaching from south-east and south the vast desert and steppe regions of Africa and Asia run out in Europe. In Southern Europe, chiefly in Spain, arid steppes having desert-like appearance are to be found. The fact that in Southern Europe steppe and desert are moving forward, provoked a heated discussion on the causes of this process and on the way to prevent it. Some people were of opinion that this process might be a more or less inevitable evolution which is due to the change of climate or to the climatic influences exerted by the Sahara. Others pointed out, that the progressive destruction of vegetation is for the most part the consequence of human activity and therefore no phenomenon decreed by fate. The latter opinion is backed up by this work in which deforestation and formation of steppes and deserts in Southern Europe is taken into consideration in order to show up the causes of this process from the geographical, historical and statistical points of view. In the course of some thousands of years forest had to give way to cultures which brought higher yields or promised more frequent harvests. However, deforestation was often followed by rather irrational economy and destructive exploitation or unrestrained pasturing. If not carried off by water or wind, a good deal of the primitive forest soil was thus transformed into uncultivated or unproductive land covered with herbs and shrubs. The effects of the dry-hot aerial currents coming from the Sahara are not to be undervalued. As far as the climate in Southern Europe is characterized by high summer dryness owing to the aerial currents of Africa, the removal of forest, its exploitation without considering a sustained yield, the burning of soil coveing and its damaging by grazing cattle easily lead there to the formation of steppes and deserts. The intensive heating of the denuded soil reduces the possibilities of growth above all in consequence of its desiccation.
