Dry stone walls are a valuable testimony about man’s past, while also concerning his present. Moreover, their role in meeting a human need has not prevented these constructions from integrating with nature, going so far as to provide support, in every sense, for wildlife.
What are dry stone walls?
According to the UNESCO definition, dry stone walls are special stone constructions that do not have the use of other materials acting as binders. The stones are carefully selected and placed on top of each other so that the weight of the stone above is offloaded onto the two below, a detail that makes drystone walls particularly stable structures.
Maurizio Bertolini, an expert in the construction of dry stone walls and whom we interviewed for this article, calls them gravity walls, which stand by their own weight. These structures are also preventive against landslides and other types of hydrogeological disruption.
The presence of these buildings shapes the landscape by causing them to become part of a collective imagination, even of those who did not build them or experience them.
Maurizio Bertolini, what story do dry stone walls tell us? What were they used for yesterday and what are they used for today?
“Dry stone walls were used in the past to develop a type of agriculture in inconvenient, unfavorable areas, such as sloping land. In such places those who began to work the land for cultivation would dig and find stones, which therefore were used. So the stones constituting the walls did not come from who knows where, but directly from the place where they were found. When we think of terraced landscapes our mind immediately takes us to dry stone walls, but these are but one component of such a landscape type.”
The terraced landscape
And indeed, dry stone walls shape what is called the “terraced landscape.” Think of the extent of these constructions in the municipalities of Calci, Vicopisano and Buti alone: roughly 2000 km! Terracing is an umbrella term that encompasses the various ways in which the morphology of a slope is modified to make it suitable for cultivation. Usually the drystone wall constitutes what is called the “embankment of the terracing,” that is, the part that contains the crop or embankment. The stones constituting the walls are coarse and of different sizes: the coarse ones form the load-bearing skeleton, while the smaller ones are embedded in the gaps and crevices between one coarse stone and another, so as to provide more stability.
The wall is then always associated with a water regulation system that helps maintain slope stability.
Bertolini continues, “At the base of each terracing was a small water drainage channel. In fact, the dry stone wall promotes water drainage, and thus lends itself particularly well to the cultivation of those plants that do not tolerate water stagnation, such as olive trees and vines. It also gives stability to the slope that has been cleared and reclaimed to make way for terracing.”
…Not only on Mount Pisano
The art and phenomenon “dry stone walls,” declared a Unesco intangible heritage, is also an essential element of the landscape of other geographical areas. Characteristic of rural areas, for the reasons we have described above, in sloping and steep areas, from the sea to the mountain ranges. Outside Italy, we also find them, for example, in Slovenia, Croatia, Greece, France and Cyprus.
PIT Project
Thanks to a PIT (territorial integrated plan) call held as part of the 2014-2020 Rural Development Program of the Tuscany Region, from 2018 to 2022 more than 4300 square meters of dry stone walls were reconstructed on Mount Pisano, with associated water drainage structures. The occasion also led to important work on the restoration of terracing, the improvement of the trail network on the Mount, and the (essential) construction of fencing for protection from wild animals.
The company that formed the lead contractor for the work was Timesis Srl. This was followed by the companies Pardi associati, PFM, NET7, with the collaboration of the Pisa CAI. The purpose of the project was to enhance and protect the landscape of Mount Pisano, as well as to collectively engage and activate for the prevention of hydrogeological instability phenomena. Participation was remarkable, thanks to the involvement of public agencies as well as private citizens.
There has also been no shortage of parallel, obviously inherent projects, such as that of the Scuola Superiore Sant’Anna on the “Management of Hydraulic-Agricultural Arrangements in Monte Pisano,” and the comparative analysis performed by herpetologist and researcher Marco A. L. Zuffi (and his team) of the University of Pisa on the presence of reptiles in the olive groves of Monte, which we will discuss in more detail below.
Nature Conquers
“The dry stone wall is a living structure, encouraging the establishment of herbaceous plants and local fauna that find shelter among the stones.” Thus continues the chat with Maurizio, which moves from a more historical and human to a more contemporary and ecological realm. Indeed, as we walk along the side of a low wall, we will undoubtedly notice succulent plants, ferns, mosses, lichens, and colorful flowers popping up between the cracks. Not only that: even at the foot and top of the little wall we will be able to spot interesting and rare plant entities, such as wild orchids. But there is more, because even wild animals such as snails and snails, insects, reptiles and small mammals do not miss the opportunity to find shelter in the crevices of the low walls. That reptiles do well in the olive groves of Mount Pisano was demonstrated through a study coordinated by Professor M. A. L. Zuffi of the University of Pisa. In particular, the presence of the wall lizard and the field lizard was analyzed, exploring six different sites on Mount Pisano, but several other reptiles were also observed, including geckos and snakes (not venomous!).
Returning to herbaceous vegetation, this is beneficial for low walls, in contrast to shrubby vegetation that can also damage the structure of the walls. In fact, herbaceous plants, by absorbing water from their roots, take up moisture and, thanks to evotranspiration, carry it away from the low wall. Together they create a firm buffer that curbs the falling stones. During winter, on the other hand, the latter are warmed by the sun’s rays, forming warmer microclimates that are absolutely beneficial for both flora and fauna.
So, on Mount Pisano these fascinating constructions have been present historically for hundreds of years and in addition to their immortal history, they give its landscape an even more fairy-tale aura…So let’s set out and observe!
Sources
Bibliography:
- Casella F., Bonari E., Galli M., Rizzo D., The management of hydraulic-agricultural systems in Monte Pisano, Scuola Superiore Sant’Anna, 2009.
- Zuffi M. A. L., Lizards and olive groves-the best place to live. A comparative analysis, University of Pisa, 2022.
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