Krásenské rašeliniště (Krásno Peat Bog) is the most extensive raised bog of Slavkovský les (Slavkov Forest). The peat bog is also known under the name V Borkách (In the dark forest) or Čistá (Clean) peat bog . It is located on the road between Krásno and Sokolov near the former small town of Čistá. The nearest bike route is cycle route No. 362 which leads through Krásno and from there, it is only about 1.5 km to the peat bog.
For thousands of years, it was an open peat bog covered with forest tree species. It had been the most significant peat bog in the Slavkov Forest until the second half of the 20th century. However, in the late 20th century, man interfered with the life of the raised bog with large-scale surface extraction of peat on dozens of hectares. This resulted in the disruption of the raised bog water system and the destruction of one of the most extensive raised bogs in the Slavkov Forest. Mining was so intense that the permitted annual mining limit was exceeded many times over and therefore, all mining activities had to be discontinued in 1999. The thickness of the peat layer now ranges from 0.5 to 7 metres. Since then, the peat bog has been undergoing slow, yet gradual and natural regeneration of its functions.
The fate of the Krásno Peat Bog is similar to that of the Soumar Peat Bog in South Bohemia where peat too had been extracted on a large-scale industrial basis until the late 1990’s. In the course of years 2003 and 2004, drain ditches were blocked and a part of the area was periodically or permanently flooded.
A small, yet valuable part in the north-eastern tip of the Krásno Peat Bog has retained its original habitat with an abundance of plant species surpassing even the unique habitats found in the Kladské rašeliny NNR. Thus, it is the most characteristic site in the Slavkovský les Protected Landscape Area. This fact is also evidenced by the considerable number of especially protected plant species dependant on high bogs, as well as the presence of almost all suitable peat moss species. Its peripheral peat and waterlogged spruce forests belong to the best-preserved in the Slavkov Forest and the neighbouring transient bogs and wetland meadows are abundant with rare and protected species of wild flora. The site, nonetheless, has still not been subject to in-depth floristic and entomological research.
The areas affected by mining are gradually inhabited by heath (Calluna), bog bilberry (Vaccinium) and cowberry (Vaccinium vitis-idaea). The peat moss spreading through old canals is retaining water and thereby, the rising water levels contribute to the further development of the peat bog. Narrow leaved cotton grass (Eriophorum angustifolium) and cotton grass (Eriophorum vaginatum) may once again be encountered in the damp locations. We may presume that, after many decades, a biotope will be created, which will be the same as or at least similar to the once common habitat, fulfilling a stabilising function with respect to the landscape, namely in terms of stabilising the water regime and re-introducing the original flora and fauna species.
The preserved remnant of the former raised bog in the north-eastern tip of the bog, which was never touched by human hand or dewatered, may well serve this purpose. The virgin site is a raised bog with Swiss mountain pine (Pinus rotundata) stands. Many plant species typical for this biotope may be found here: e.g. round-leaved sundew (Drosera rotundifolia), cranberry (Oxycoccus palustris), bog rosemary (Andromeda polifolia), black crowberry (Empetrum nigrum) and many other species, including rare bryophyte species.