A Unique Natural Sight
On the southern shore of the Cape Karkalinniemi, about three kilometres from Karkali Strict Nature Reserve, is located a unique natural sight: Torhola Cave and Pitkänperänlahti Nature Reserve form a combination of rock, cave and herb-rich forest, which is exceptional in Finland. Torhola limestone cave is a popular attraction, and you can get there by following a trail which separates from the road going to the Cape Karkalinniemi.
The western part of Torhola rock area is included in the Herb-rich Forest Conservation Programme, and partly also in the Shore Conservation Programme. In addition, the western part belongs to the Natura 2000 network and to a nature reserve of Metsähallitus.
The Largest Limestone Cave in Finland
In the western part of the rock area, which is located on the steep southern side of the Cape Karkalinniemi, there is the largest cave in Finland. The cave is about 30 metres long in total. Until about half way it is quite wide, but towards the end it gets narrower. Be careful, if going into the cave!
Most part of the cave has been formed after the last Ice Age, when the impure limestone has been eroded from the acidic gneiss. The rock foundation in the area is mostly striped, acidic gneiss. In the surroundings of the cave, there are layers of crystalline limestone and chalky gneiss inside the acidic gneiss. Because of the chalkyness of the rock foundation, there are several valuable rock and herb-rich forest areas.
Valuable Herb-rich Forest and Rock Vegetation
The flora in the rock area of Torhola Cave is unique. In the herb-rich forests, on the slopes descending to Lake Lohjanjärvi, grow, for example, the Wych Elm (Ulmus glabra) and the European White Elm (Ulmus laevis). The calciferous soil of the rocky hill is rich in nutrients, and the shadowy cliffs also offer exellent conditions for many other demanding plants. Plant species growing in the area include the Teesdale Violet (Viola rupestris), the Basil thyme (Satureja acinos L.), and the Maidenhair Spleenwort (Asplenium trichomanes). The set of fungus species is remarkable, for example, the threatened Limacella guttata, Rhodocybe gemina, Kavinia himantia and Gyromitra warnei grow there. Rare species of the area include the moss Plagiomnium rostratum, the lichen Solorina saccata and the Bird's-Nest Orchid (Neottia nidus-avis) . The endangered beetle Pseudonostirus globicollis is a rarity of insects, which lives in the area of Torhola Cave.
The area of Pitkänperänlahti Bay is included into the Shore Conservation Programme. Common hazels (Coryllus avellana) grow in shoreline herb-rich forests and there are open flood meadows, and flood meadows on the waterside with black alder (Alnus glutinosa) growing in them. The Yellow Woodland Anemone (Anemone ranunculoides), the Dog's Mercury (Mercurialis perennis) and the Wood Stitchwort (Stellaria nemorum) also grow in Pitkänperänlahti area.