The Boubín primeval forest NNR is a forest complex on the peak of Mt. Boubín and the slopes of the Pažení ridge, 2 – 6 km north of the village of Zátoň within the Šumava PLA.
Parishes: Včelná pod Boubínem and Horní Vltavice (Jihočeský kraj – South Bohemian Region)
Area: 677.33 ha
Elevations: 874 – 1362.2 metres above sea level
Declared: 1933 (but protected by the landowners from 1858).
The subject of the protection is the remnants of the natural primeval forest complex on the steep slopes of the Pažení ridge and Mt. Boubín. Further remnants of varying sizes and with varying levels of human interference are scattered throughout the surrounding cultural spruce forests. The NNR contains a species-rich collection of rare, endangered and locality-significant plant and animal species. The Boubín primeval forest is one of the oldest and most well known protected areas in the Czech Republic and central Europe and the oldest reserve within the Šumava mountains region.
The Pažení (Basumský) hřbet ridge, the summit of Mt. Boubín (1362.2 metres) and the flat ridge running in the direction of Mt. Bobík form a massive natural amphitheatre with steep slopes and opening to the south-east. The deeply incised Karlický potok stream rises and flows down through this amphitheatre. The rocky basement is formed of pearl gneisses and nebulites but the monotonous series of paragneisses of the Moldanubicum can also be found here. The bedrock is only exposed in the form of tors and less developed frost-riven cliffs, especially on the Pažení ridge and the summit of Mt. Boubín. The slopes of the Kaplický potok valley are covered with thick layers of weathering products, which forms gravelly and loamy talus with accumulations of clay sediments in places. The soils are predominantly of the podsol type.
As a result of the exceptional differences in elevations in the reserve we can find 3 basic vegetation units here: herb-rich beechwoods of the Fagion type, acidophilous montane beechwoods (Luzulo-Fagion) and climax spruce forests of the Piceion excelsae.
The largest area is covered by acidophilous spruce-beech stands with small-reed (Calamagrostio villosae-Fagetum), which cover the upper parts of the slopes, approximately above 1050 metres. Lower-lying areas are covered with herb-rich beechwoods with toothworts (Dentario enneaphylli-Fagetum). The tree layer in the natural, herb-rich beechwoods consists of beech (Fagus sylvatica), Norway spruce (Picea abies), silver fir (Abies alba), sycamore (Acer pseudoplatanus) and wych elm (Ulmus glabra).
The species-rich herb layer in these forests includes upland enchanter’s nightshade (Circaea × intermedia), yellow archangel (Galeobdolon montanum), nine-leaved toothwort (Dentaria enneaphyllos), coralroot (Dentaria bulbifera), herb Paris (Paris quadrifolia), baneberry (Actaea spicata) and oak fern (Gymnocarpium dryopteris), with fir clubmoss (Huperzia selago) in talus covered areas. The shrub layer includes black-berried honeysuckle (Lonicera nigra) and mezereon (Daphne mezereum). With the exception of lighter and wetter areas, the herb layer in the acidophilous beechwoods with small-reed is very poor. In addition to the hairy small-reed (Calamagrostis villosa) it also includes whorled Solomon’s seal (Polygonatum verticillatum) and purple lettuce (Prenanthes purpurea) as well as relatively large colonies of interrupted club-moss (Lycopodium annotinum).
The forest stands on the top of the Pažení ridge and the summit areas of Mt. Boubín have the character of human-modified climax spruce stands with small-reed (Calamagrostio villosae-Piceetum). The least influenced and most natural are the spruce stands on the upper north-eastern slopes of Mt. Boubín. Here the undergrowth includes hairy small-reed, wood-rush (Luzula sylvatica) and small, scattered growths of Alpine lady fern (Athyrium distentifolium).
The moss layer is often dominated by broomfork moss (Dicranum scoparium), cypress-leaved plait-moss (Hypnum cupressiforme) and the haircap moss Polytrichum formosum.
Azonal stands of waterlogged spruces of the Mastigobryo-Piceetum association can be found in inversion positions and on water-influenced soils and the carpet of mosses in these stands also includes the rare lesser twayblade (Listera cordata) in several places.
Numerous springs with hygrophilous vegetation of the Cardaminion amarae alliance are found on the gentler slopes, with small streams flowing from them, where we can find fringes of tall herb vegetation with white butterbur (Petasites albus) as the dominant species. Rare moss species, such as the liverwort Riccardia multifida and large-leaf thyme moss (Rhizomnium magnifolium) can also be found here. Chickweed willowherb (Epilobium alsinifolium), which is one of the rarest species in the Šumava mountain range can be found around the talus forest springs above the primeval forest.
Thanks to the quantity of rotting wood and high air humidity, the Boubín primeval forest is an exceptionally valuable and unique bryological locality. Among the common epixylic mosses which grow here are wood-rust (Nowellia curvifolia), the pincerwort Cephalozia catenulata, Swedish pouchwort (Calypogeia suecica), palmate germanderwort (Riccardia palmata) and the very rare notchwort Lophozia ascendens also grows here. The moss Anacamptodon splachnoides and green shield moss (Buxbaumia viridis) were also recorded here in the past.
The reserve is notable for the occurrence of certain epiphytic lichen species, such as Lobaria pulmonaria and the microlichens Cyphelium inquinans, Mycobilimbia epixanthoides and Pertusaria hymenea.
The Boubínský prales primeval forest is among the most significant and most researched mycological localities in the Czech Republic and is well-known at home and abroad. Several fungi species have their only locality in the Czech Republic here, including the protected cup fungus Pseudorhizina sphaerospora, the bracket fungi Phellinus ferrugineofuscus and Phellinus nigrolimitatus, the brittle-fleshed fungus Laurilia sulcata and the shelf fungus Juhghuhnia fimbriatella. Critically-endangered and legally protected fungi species include Hydropus atramentosus, Phellinus pouzarii, Camarops tubulina, Amylocystis lapponica, Ascotremella faginea and Pseudoplectania vogesiaca. Rare mycorrhizal fungi such as the woodwax fungus Hygrophorus piceae and the milkcap fungus Lactarius repraesentaneus grow here. The cup fungus Pseudoplectania vogesiaca and the coral fungus (Hericium flagellum) are bound to the fir trees.
Among the most important flora discoveries in the reserve in the last 3 years are the rediscovery of the ghost orchid (Epipogium aphyllum), orchid Corallorhiza trifida and the moonwort Botrychium multifidum, which was previously extinct in the Czech Republic.
Many significant and rare invertebrates have been found in the reserve, including several Rhizopoda species, the worm Lumbricus baicalensis and the nematode Tylenchus butteus. The dominant molluscs in the reserve are the snails Punctum pygmaeum, theglass snails Vitrea subrimata and Aegopinella nitens, dentata thorn snail (Carychium tridentatum) and brown hive snail (Euconulus fulvus). The millipedes Mastigona mutabilis and Pachypodoiulus eurypus also occur here along with more than 60 species of springtails (Collembola) and the jumping bristletail Machilis bohemica. Significant beetles which have been recorded in the Boubín forests include the rove beetle Mycetoporus splendens, the leaf beetle Oreina speciosissima and the weevils Otiorhynchus morio, Barypeithes araneiformis and Acalles hypocrita as well as the Diptera species, including the solitary fly Thaumalea bezzii, the small dung fly Crumomyia rohaceki and the hymenoptera species include Aphycus sumavicus of the Eneyrtidaewhich was first described from Boubín and a few other localities.
Significant vertebrates in the reserve include the hazel hen (Bonasa bonasia), which is bound to the pioneer stage of development of the mixed forest stands. Birds which nest in hollow trees are typical for Boubínský prales NNR, including the woodpeckers: grey woodpecker (Picus canus), black woodpecker (Dryocopus martius), great spotted woodpecker (Dendrocopos major), white-backed woodpecker (Dendrocopos leucotos) and three-toed woodpecker (Picoides tridactylus). Hollow trees also provide nesting sites for the stock dove (Columba oenas)and the red-breasted flycatcher (Ficedula parva), which normally prefers younger, thicker beechwood stands. Uncommon owl species in the reserve include the Ural owl (Strix uralensis), Tengmalm’s owl (Aegolius funereus) and pygmy owl (Glaucidium passerinum). The ring ouzel (Turdus torquatus) regularly nests in the climax spruce stands on the Pažení ridge and on the summit of Mt. Boubín.
Notable mammal species in the reserve include the Alpine shrew (Sorex alpinus), European water shrew (Neomys fodiens), southern water shrew (Neomys anomalus), hazel dormouse (Muscardinus avellanarius) and lynx (Lynx lynx).
The original area of the primeval forest which was protected by the landowner in 1858 was 143.7 ha. As a consequence of wind calamities and the following bark beetle infestations, especially in the forest stands which had been disturbed by logging on the Pažení ridge and around the summit of Boubín, felling was also carried out in the previously untouched forests and the reserve’s area was reduced to 46.67 ha. It took until 1958 before the value of the natural forest stands around the primeval forest was recognized and these forests were included in the enlarged reserve.
The core territory of the primeval forest was fenced off in the 1960s to protect it from the devastation caused by deer and visitors. The proportions of tree species in the primeval forest have gradually changed over the last centuries. The proportion of fir trees has fallen considerably and these have been replaced by a large proportion of beeches. Spruce has maintained its dominant position in the reserve (c. 50%). Approximately one third of the area is covered with advance growth which is dominated by beeches. In other areas the silver firs and spruces are also rejuvenating successfully along with other scattered tree species. The largest trees in the reserve are spruces and firs with an average trunk diameter of 160 cm at breast height, more than 50 metres in height and 400 – 500 years old. The greatest spruce, which stood in the middle of the primeval forest area at an elevation of exactly 1000 metres above sea level, fell during a windstorm on 4th December 1970 after reaching a height of 57.6 metres and was estimated to be 440 years old. Other remnants of primeval type forest stands are scattered in the surroundings of the primeval forest proper and can even be found on the summit of Mt. Boubín. Beeches are becoming much stronger in these natural mixed forests, which have their upper limit at around 1200 metres. The spruce stands on the north-eastern slope of Mt. Boubín include remnants of primeval climax spruce forest with the oldest trees around 250 years in age.
The remainder of the NNR territory is covered with cultural spruce plantations, which were mostly planted on the clear-cut areas which resulted from various calamities in the late 19th century. However, these younger stands contain around 10% of older spruces, which are certainly the remnants of the natural spruce forests.
The hurricane Kyrill which hit the area on 18th January 2007 brought dramatic changes to the forests, especially on the ridge and will have long-term impacts on the forest’s development.
The NNR territory is one of the most-visited localities in the Šumava mountain range. Several marked trails pass through the reserve and a themed nature trail runs around the edge of the historical primeval forest. This territory is one of the few places where it is possible to observe the natural behaviour of forest ecosystems. At present a legal process is under way to determine the responsibility of the owners and operators of the themed nature trail in the event of an “act of God” when a tree falls across the trail.