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B. Baran-Zgłobicka & W. Zgłobicki 2010. Forest patches in agricultural landscapes (loess areas of SE Poland)
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2. Methodology
The analysis of the changes in land use was carried out by comparing three maps: Karte des
westlichen Rußlands 1: 100 000 (representing the year 1890), Tactical map of Poland WIG 1:
100 000 (representing the year 1935), and a modern land use map 1: 25 000 (representing the
year 1997, elaborated based on aerial photographs and field mapping). The first two maps were
digitized and calibrated. The next step consisted of the creation of maps (layers) of wooded
areas with the use of ArcView software. The map compilation and the selection of chosen
separations enabled the analysis of how the percentage of forest cover changed over time as
well as the examination of the links between those processes and natural determinants. A map
dating back to 1840 was also available but did not lend itself to cartometric analysis. Hence,
only an approximate percentage was calculated for the forest cover in that year.
The above-mentioned cartographic materials indicate that woodlands and forests are the only
land use category that could be examined in relation to such a long period of time. At the same
time, they constitute the most “natural” component of the land cover. The spatial analysis
included the assessment of changes in the area of forest patches as well as selected statistical
parameters prepared for three periods: 1890-1935, 1935-1997, 1890-1997. In addition, an
examination has been conducted with respect to the character of the abiotic components in areas
covered by forests in various periods as well as in areas where forestation or deforestation took
place.
3. Results
The studies revealed differences in the scope of changes in the percentage of forest cover in the
test areas.
- In the Wąwolnica test area, the forest cover decreased by 2.8 km 2 over the last 100 years; the
lowest forest cover occurred in 1935 (11%)
- In the Wilczyce test area, the percentage of forest cover increased more than fivefold over the
last 100 years. At the end of the 19 th and beginning of the 20 th century it was less than 0.5% (see
Figure 1)
- In Wilczyce, gullies are the only contemporary form of relief with a considerable forest cover.
In Wąwolnica, the percentage of the forest cover on steep slopes is also relatively high.
- In Wąwolnica, an increased number of forest patches was observed, along with a decreased
mean patch area. The diversity of the shapes of the patches has also increased (see Table 2).
Nowadays, the mean patch area is particularly small in the case of Wilczyce.
- The loess plateaus as well as gentle and medium slopes were deforested in the Wąwolnica test
area (see Table 3), while in the Wilczyce test area this process was not observed.
- In both test areas, the forests occupied the area of gullies and steep slopes.
4. Discussion
The presented results show the rationality of changes as regards the usage of the agricultural
production space. In Wąwolnica, the plateaus and gentle slopes, convenient for agricultural
cultivation, were deforested during the last 100 years, whereas in Wilczyce this process took
place before the 19 th century. After World War II, an increase of forest areas occurred in both
test areas. The succession of forests occurred in areas with a significant threat of soil and gully
erosion. Nowadays, this process also occurs in connection with a decline in the profitability of
agricultural production.
The differences in the percentage of forest cover between the test areas should be linked with
natural and socioeconomic conditions. The clearly larger area covered by forests in Wąwolnica
results from the relief of the area, i.e. a large proportion of steep slopes and gullies. The
Forest Landscapes and Global Change-New Frontiers in Management, Conservation and Restoration. Proceedings of the IUFRO Landscape Ecology
Working Group International Conference, September 21-27, 2010, Bragança, Portugal. J.C. Azevedo, M. Feliciano, J. Castro & M.A. Pinto (eds.)
2010, Instituto Politécnico de Bragança, Bragança, Portugal.