Forest site types and soil cover in the Roztocze National Park – the current state of knowledge

The forest sites and soil survey conducted by the Bureau for Forest Management and Geodesy, Branch in Lublin in the years 2009–2010 involved all of the Roztocze National Park (RNP). The studied area was 8335.31 ha. Throughout the Park, 417 soil sampling plots (open pits) and 2,400 auxiliary soil sampling plots (soil boreholes) were established. A total of 28 soil subtypes, subsumed under 14 soil types, were identiied, with the most abundant soil type being rendzina. Furthermore, 17 forest site types were described, including 12 lowland and 5 upland forest site types. Two upland forest types (upland broadleaved forest and upland mixed broadleaved forest), were found to be predominant in the National Park.


INTRODUCTION
The objective of the forest sites and soil survey was to identify soil types and subtypes and forest site types, to describe their diversity, delineate their ranges, and measure their areas. The results are useful for long-term planning and sustainable forest management, as well as natural protection.
The irst thorough forest site types and soil survey for the Roztocze National Park (RNP) was carried out by the Habitat Unit of the Bureau for Forest Management and Geodesy (BFMG), Branch in Warsaw and Lublin at the beginning of the 1990s (6). That survey involved an area of 7948.54 ha and was based on 355 soil pits. It was later updated with an annex made by the Habitat Unit of the BFMG, Branch in Lublin in 1996 (7). That project involved a forest area of 441.59 ha, which had been transferred to RNP by the zwierzyniec Forest District. The last forest site types survey of RNP was performed by the BFMG, Branch in Lublin in the years 2009-2010 (8). The results of the above survey are presented in this publication.
It should also be emphasized that apart from the above-mentioned comprehensive surveys carried out by the BFMG, the soil cover of RNP has been the subject of many studies and analyses (2,3,10,11). The results of those studies relect an evolving approach to the systematics and classiication of soils, which makes them dificult to compare.

STUDY AREA, MATERIALS AND METHODS
The forest site types and soil survey conducted by the Bureau for Forest Management and Geodesy, Branch in Lublin in the years 2009-2010 involved all of the Roztocze National Park (RNP). The studied area encompassed 8335.31 ha. Fieldwork was started in April 2009 and concluded in April 2010. A total of 417 soil sampling plots (soil pits) were established, with one sampling plot per 40 ha, on average. A thorough description of the soil proile was made for each soil pit with samples taken for laboratory analysis. Furthermore, the tree cover and the herb and moss layers were characterized. The herb and moss layer was studied twice to relect its spring and summer aspects. In order to delineate the actual borders of soil units and forest site types, 2,400 auxiliary soil sampling plots (soil boreholes) were established, with one site per approx. 4 ha, on average. In the ield, the borders of soil units were delineated in line with the natural borders of forest site types. A total of 1,291 soil-and-site types units were deined, with an average area of 4.5 ha. The density of sampling sites was uneven. The location of boreholes was determined on the basis of land relief and the spatial habitat pattern. The survey was conducted in accordance with the Forest Management Guidelines, Part 2 "Guidelines on Site Types Identiication and Mapping" (4) and the Classiication of Forest Soils in Poland (8). Along with soil and forest site types identiication, also the state of site types was diagnosed in terms of the degree of consistency or the nature of inconsistency of a given site with its natural form. Pursuant to the guidelines contained in the "Habitat-Based Forest Silviculture" (9), forest types were used as units for forest site types. Forest types determine the general forest cultivation goals linked to the forest-forming roles of the trees found in a given habitat. Forest types were identiied and classiied based on the species composition of trees and the site potential determined by the edaphic conditions of a given forest community. The survey provided the basis for drafting of soil and habitat maps for the entire area of RNP at 1:10,000 and 1:25,000 scales as well as for publishing the Habitat Report, which contains a detailed descriptive part, tables, and documentation materials. The soil pattern of the Roztocze National Park is closely linked to the properties of the soil parent materials, the local hydrological system, and the land relief (2). The predominant soil materials are sands, which occupy more than half of the park's area. They are particularly abundant in the south and in the vicinity of the Wieprz River (1). These sands are locally wind-blown and some high dunes are present. Furthermore, a large area is occupied by clay materials, which are typically deposited on limestone detritus. Small areas of RNP are also covered with silty loesses, which underlie the most fertile soils and forest habitats. The parts of the park at lower elevations, especially in the south, are covered with moist organic sediments, which typically gave rise to peat and muck soils.
During the 2009-2010 survey, 28 soil subtype units (subsumed under 14 soil types) were identiied and delineated in the ield (Fig. 1). In terms of area, the pre- 2. The methodology and scope of the present forest site types and soil survey of RNP are similar to those of the surveys conducted for the other forest areas in the Roztocze region, which are at the disposal of the management of the "State Forests" National Forest Holding.
3. Taking into consideration the natural changes to forest ecosystems occurring in RNP as well as the measures undertaken under the Protection Plan and leading to tree cover transformation, it would seem advisable to update the present forest and soil survey in the future.