Pluh’s pine grove, the original pine forest on serpentine

The tree that best withstands the specific substrate on the serpentine is the pine. Cultivated spruce forest, which was planted here in the past, is gradually being converted back to lighter pines on the serpentine.  Serpentine pines tend to have a rich, developed herbaceous layer and are home to a number of rare species.

A view of the seventeen-year-old fenced area in the National Nature Reserve Pluh’s pine grove, which was built to protect regenerating trees. Here, the natural herbaceous undergrowth with winter heath has fully developed. However, the young pine trees could not be saved. Photograph by P. Tájek

The National nature reserve ‘Pluh’s pine grove’ preserves the largest serpentine pine grove of a natural character in the Slavkov Forest area. Despite targeted conservation management and careful forestry management, natural forest regeneration has not been achieved in the long term. In recent decades the non-native sika deer, which has become highly overpopulated throughout the area, has found a peaceful refuge here. They are significantly damaging the natural regeneration, pine plantations as well as herbaceous layer of the forest. The pressure of overpopulated deer is in some places so strong that the vegetation is absent over large areas. The pine forests are gradually changing into species-poorer and shadier forests with a higher proportion of spruce. Before the arrival of humans, the local serpentine forests burned relatively often, on average once every 170 years. This resulted in very distinctive, sparse pine forests with a high density of small shrubs – winter and summer heather, blueberries and cranberries. The sparse forest allowed the survival of some light-loving plants that were present in the mostly forest-free Central European landscape during the last ice age. Some of these plants have evolved over the millennia into new species that have adapted to the specific conditions on the serpentines to such an extent that they cannot grow anywhere else – for example, Knautia serpentinicola (Serpentine scabious) or Cerastium alsinifolium (endemic type of mouse ear chickweed), which only grows on the Mnichov serpentines and nowhere else in the world. Other typical and rare species include winter heather, shrubby milkwort and wild carnation. The serpentine rocks in the pine forests are home to numerous populations of rare serpentine ferns – Snake spleenwort and corrupt spleenwort. With the arrival of humans in the Middle Ages, the local forests burned even more frequently, and in the mid-20th century, completely open heathland areas prevailed across a significant part of the territory of today’s National Park.

The current efforts of conservationists and foresters are to significantly reduce the deer population and thus restart the natural regeneration of pine tree groves. The current adverse development of vegetation is partially compensated by cutting down spruce trees from the understory of aging pine groves, lighting up rock habitats and creating fenced areas. However, no pine trees have grown in the fences to date – occasional damage to the fencing by fallen or broken trees has allowed the overpopulated game to repeatedly destroy the rejuvenating trees.

The unfenced section has been completely grazed by forest animals – the herbaceous layer is almost nearly missing. Photograph by P. Tájek.
The sika deer. Photograph by P. Korelus.
Serpentine rubble and rocks in the National Nature Reserve Pluh’s Pine Grove. Photograph by P. Tájek.
Corrupt spleenwort. Photograph by P. Tájek.
The largest population of endemic Cerastium alsinifolium (mouse ear chickweed) can be found in the light forest areas at the foot of a serpentine ridge. Photograph by P. Tájek.
The woodcock. Photograph by P. Lang.