Functions and Conditions of Construction of Stone Walls
Mountainous areas, especially those built of crystalline rocks, are characterized by highly skeletal soils, which pose many problems for agriculture. However, due to the considerable overpopulation of villages in the study area and agricultural use of even less useful lands, it became essential to clear the arable lands of rock debris and boulders to make farming possible.
It needs to be stressed that removing rock debris is not a single procedure of preparing the land for farming, especially in the moderate climatic zone. The debris has to be constantly removed, as it appears on the surface of fields regularly as a result of both agricultural (ploughing) and natural processes (freezing of deeper parts of the ground, uncovering the debris due to erosion and washing-off smaller fractions) (see Cronon 1983; Thorson 2004). The initial function of removing rock debris was to prepare the land for farming (removing larger blocks and boulders) and afterwards – its maintenance during agricultural usage of the land (removing smaller fragments that appear on the surface later). In order not to waste the surface of arable lands for storing rocks, they were placed in less useful places (e.g., close to rock outcrops or along balks or watercourses that marked property borders and field divisions). At the same time, erecting stone walls and enclosing small fields was a good solution to protect the shallow mountain soils from wind and water erosion.
In order to realize how extensive clearing of the fields was done, one has to take a look at the forested areas of neighboring fields. There are numerous gneiss blocks and boulders whose estimated weight exceeds a few tons. In the process of preparing the land for farming, it was not enough to gather small stones from the surface, it was also necessary to crush larger blocks and boulders, transport them, and to place them in a border wall.
During a field survey conducted in the forest between the villages of Kopaniec and Górzyniec and toward a southeasterly direction, some fragments of unfinished walls have been discovered. Small prisms of stones, probably prepared for transport to the field border, were found. However, the surrounding area was not even and there are still numerous boulders on the surface. These finds prove that the preparation and recovery process was not finished in every case. Some ongoing ventures were abandoned for unknown reasons. Perhaps this was also somehow connected with the process of industrialization as new factories appeared in the region (especially in the biggest city in the region – Jelenia Góra – in the nineteenth century). New possibilities of factory work resulted in mass migration of former peasants to the cites (Walczak 1968).
At the foot of a stone heap in Górzyniec, just as in the case of the walls in the vicinity of Kopaniec, we found crushed boulders up to 2 m long. They must have been transported by a couple of people, using draft animals and appropriate constructions such as ramps and levers, especially needed when stones had to be placed high on the wall. Based on observations of unfinished fragments of walls, we assume that the process was conducted gradually. Stones were set in prisms of 2–3 m in diameter and around 1–1.5 m high, 10–20 m apart from one another, and then the gathered material was transported to the border wall or used in another way. We can presume that the stones collected in the lower parts of the village, with better transport options, were used as building material not only for those who lived in the village, but also for people from the nearest neighborhood.
The walls did not only function as borders, but were also used for other purposes, which is evidenced by the niches. The role of these structures is unclear. We can assume the largest ones were helpful in field work. They could have combined the functions of temporary storage and provisional dwelling. They could have accommodated a cart or animals inside without any problem. We know nothing about their roofs. During the study, no traces of wooden constructions of roofs or doors were recorded. It is possible, however, that the niches originally could have been covered with simple hut-like roofs that were regularly changed. Defining the function of two small niches in the vicinity of Chromiec is more difficult (see Table 1). Such a small construction could have served only as a storage place, possibly for temporary tools, food, or firewood.
A small amount of archaeological material found during the prospection of the niche in Kopaniec suggests that this site was not frequently used as a dwelling and served rather supportive functions. Traces of fire indicate that the niche was occasionally used for preparing food or providing warmth. It also served as a protection from the wind and could have been originally covered with a hut-like roof. We do not associate the construction of the niche with the time right after the field had been delineated. It is suggested among others by a regular layer of stones set against the walls of the construction. They were erected sometime after the heap had been raised. It is probable that the construction of the prism took many years and that the ancillary construction was built early. The lack of comprehensive archaeological research of other niches does not allow the determining of a more precise chronology. Possibly they are not the result of a single venture. The idea to erect niches could have been taken over by many generations of farmers and spread wherever walls were constructed. In the area of Chromiec, presently in a forest southwest of the village, there are fragments of walls with niches of similar size and with a face of the wall clearly marked on the edge. These constructions were only one or two stones high. However, we can see that they were planned very early, in the initial phase of the construction of the wall.
It is hard to clearly state whether the walls were constructed on previously delineated borders, or the borders of a future field were defined based on estimations of how much work would be needed. It is possible that the process was connected with exemptions from fees for several years and then the size of a plot depended on worktime and the number of people who were involved. In the first stage of field development, the largest stones were removed, and the foundation of the wall was laid. These stones bear traces of drilled holes and are of considerable size. In the following years, more stones were added to the wall successively collected during field works. It is the only clear evidence that some of the recorded walls were built over a long period of time. That occurred in cases of very large constructions built with the use of a lot of small stones collected successively each year after plowing.
Border stones were found within walls only in some cases. However, it is unclear whether they were placed after the wall had been erected and connected with validation of the wall or if the delineation was done at the very beginning. Further studies will be necessary to answer this question. Border stones were mainly small cuboids with a sign of an isosceles cross. The signs were sometimes carved into unworked stones. The stones were placed along walls, less often on their top. Single border stones can also be found outside these structures. Property borders delineated in this way were confirmed on official cadastral maps in the mid-nineteenth century (Fig. 8).
Stone field borders recorded in the Sudetes show how the local population was determined to deal with a deficiency of arable lands. To some extent they show tendencies that are better recognised in the British Isles and in northeastern USA. Similar phenomena occurred in the high-altitude zones of New England. According to Thorson (2005), wide, regularly shaped walls indicate that a lot of effort in a short period of time was put into clearing fields and meadows. After some time agricultural activity was stopped and the fields were spontaneously overgrown with forests due to vegetation succession (Johnson and Ouimet 2018; Thorson 2004, 2005). In the area discussed in this paper, the process was similar, although conditioned by different economic and political factors, not only industrialization but also population exchange after World War II.
It is also mentioned in the literature that walls were disappearing due to changes in agricultural techniques and the merging of small fields (Duchoslav 2002, Johnson and Ouimet 2018; Thorson 2004). The following factors are thought to have led to the decrease in profitability of agricultural production on small farms: the development of the railway, new possibilities of earning money in the western part of the country, soil depletion, mechanization, and government support (Allport 1994). However, in the study area the former agricultural areas were left entirely aside after abandonment and no modern developments have been observed. Only natural afforestation could be observed locally in these areas. Therefore, most of the old stone structures are still preserved in the landscape, and usually in a good state. It has been proven by extensive research that stone walls not only have historical value, but are also important elements of the ecosystem. Those that were constructed without mortar function as shelters and provide good conditions for many species of plants and animals (Affek 2016a; Collier 2013; Schreg 2016).
Spatial Differentiation of Size and Forms of Stone Walls and Heaps
The size of walls and their construction techniques depended on how much rock debris was on the surface. When there was little debris, it was enough to gather it and form a prism or a loose wall. But when there was more debris and large boulders and blocks, more effort was necessary and walls up to a few meters were carefully constructed.
The occurrence of stone fences enclosing fields can be clearly associated with higher and steeper parts of slopes, and further location from buildings, while walls that did not form closed fences are more common in areas situated at lower altitudes and gentle slopes, directly next to human dwellings. It might be connected on the one hand with more intensive water and wind erosion on slopes where the slope angle exceeds 10° and at higher altitudes, which required more effective solutions that would provide protection for the soil cover. Moreover, higher and steeper parts of the slopes are generally connected with a thicker layer of debris in the Sudetes. Lower parts of slopes and flattened foothills and valleys, in which fine-grained fraction material accumulate, have a lower percentage of boulders and blocks, and that is why preparation for farming did not require the removal of such large amounts of rock material as in the higher parts of slopes.
The size and density of the distribution of stone walls and prisms can also be associated with the lithology of the geological substratum. In contrast to some other regions, for example, the northeast of the USA, where the walls were largely built from stony material from glacial till (Johnson and Ouimet 2016; Thorson 2004, 2005), the study area was never glaciated in the Quaternary (Migoń 2005). However, it was subject to a periglacial climate in that period, which favored an intensive mechanical weathering of rocks due to frost action. It contributed to the formation of extensive block covers on slopes, which later became the source of building material for walls. While the bedrock lithology is generally homogenous in the study area, there could have been variations in the abundance of rock debris in the slope/soil cover related to former bedrock outcrops and the intensity of its weathering. It results nowadays in an uneven distribution of wall densities and sizes. Morphometric analyses conducted in other parts of the Sudetes, on different types of geological substrata (gneisses, granites, sandstone, mica schists) clearly indicate that the largest stone structures are connected with the occurrence of gneisses in the bedrock (Latocha 2012, 2014). Outside the Izera Mountains the largest constructions were identified in the Bystrzyckie Mountains in the central Sudetes, also based on gneisses. Walls in that area are up to a few hundred meters long, up to 1.4 m high and 5–6 m wide, while heaps are up to 30 m long, up to 20 m wide and up to 2–3 m high (Latocha 2012). Nevertheless, they never formed closed fences as occurred in the study area.
The distribution of stone walls preserved in the zone neighboring on the south of the villages of Antoniów, Chromiec, Kopaniec, Kopanina, and north of Górzyniec, reflect the topography of fields organized in the period of demographic growth and the need to extend the surface of arable lands. Intensive adaptation of wastelands for the needs of agriculture can be dated to the modern period (seventeenth–nineteenth century), namely right after the Thirty Years’ War (1618–48), or to industrialization that started in this area in the second half of the nineteenth century and provided alternative money-earning opportunities for the local population and the extensive outflow of inhabitants of mountain villages. The shifts of political borders and the exchange of population after 1945 additionally enhanced the process of permanent abandonment of many fields.
In order to establish the chronology of wall construction we should also have information on the initial forest clearances. However, we do not know what part of the area was covered with forests. It seems that it was deforested earlier in the period when forest glassworks requiring large amounts of fuel were active (ca. 1330–1400). The species composition in the forests surely changed at that time. The demand for beech wood caused the need to replace it with different species. Unlike many other areas in the world, where deforestation occurred as a result of agriculture (i.e., in the northeastern part of the USA; see Johnson and Ouimet 2016; Thorson 2004), forest cutting in the Sudetes Mountains was primarily related in many areas to glass manufacturing. The resulting open areas were only subsequently occupied by agriculture (Walczak 1968).