Abstracts I - Erosion and population

Watershed management and afforestation between the 19th and 20th century in Italy

Mauro Agnoletti, Universitá di Firenze

In the second half of the 19th century many European countries having parts of their territory included in the Alpine regions developed polices for afforestation and watershed management. The need to improve the environmental conditions of the mountain regions reducing landslides on the mountains and floods in the plains, required the development of a body of techniques adapted to steep mountain slopes, but also to deal with the socioeconomic problems of the mountain populations, not always ready to accept large afforestation programs. In the case of Italy, where mountains cover more than 35% of the territory, the social problems and the technical problems that the forest administration encountered required more than 100 years  to be solved in favor of large afforestation projects. The “migration” of more than 3.500.000 people from the hills and the plains to the mountain areas, between 1861 and 1951, almost doubled the number of people living in the mountain, making about 25% of the total Italian population. In the Apennine range the mountain population almost doubled in 50 years time.  On one hand this demographic growth brought to the need to expand cultivated land and pasture on mountain slopes, reducing the extension of forest cover. On the other, the need to protect the mountains and the valley from landslides and floods had to take into account that farmers and shepherds needed land to survive, rather than forests. Initially the attention of authorities was mostly concentrated on strategies based on the experience of French engineers, which preferred to build dams rather than afforest the land. At the turn of the century however, the bad results of that choice convinced the Italian government to undertake more afforestation. The shift from a policy based on reduced state  subsidies to a robust increase of state intervention, as well as the strong will of the fascist regime to increase afforestation and watershed management, produced the most important Italian laws  for environmental protection,  and helped to extend forest cover, of about 200.000.

 However, the real increase of forest cover as well as the success of afforestation polices, occurred only after 1960, when the industrial development of the country favored the abandon  of mountain areas, bringing back the demographic situation to the one of 1861. Recent research findings shows that the socioeconomic and geological conditions of the Italian peninsula not always suggest that forests and woodlands are the best solution to fight hydrogeological risk, but rather a careful management of the territory.

Erosion processes and past climate condition in the South Alentejo

Maria José Roxo, FCSH – Universidade Nova de Lisboa

The research on information regarding extreme weather phenomena that occurred in the past in the Southern Alentejo region, along the analysis on soil use and occupation cartography, were key elements to understand the current state of decay of the ecosystems.

The used methodology was to collect qualitative information on the weather conditions and extreme phenomena (droughts, flood, storms, snowing) in regional newspapers (Bejense, Mertolense), published since mid-19th century, and in obtaining quantitative data since the time that weather stations were installed in that region of Portugal (Beja, S. Domingos Mine). Particular emphasis was given to the information regarding the municipalities of Mertola and Serpa, as they are municipalities that show vast areas with a high degree of soil degradation and loss of biodiversity (desertification).

The climatic information associated to land use changes on different soil types and propriety dimensions, allows illations to be taken regarding the dynamics of hydric erosion process and to establish phases during which the ecosystems suffered greater pressure. This knowledge facilitates the validation of future scenarios regarding current climatic changes.