Torronsuo National Park mostly consists of mire. There are many small pine forest islands in the middle of the mire. Torronsuo Mire is surrounded by forests, eskers, rocks and cliffs, where you get a great view over the different parts of the mire. Despite their location in the southern Finland, the mires of the National Park are still almost in their natural state.
The turf layer, which has taken thousands of years to grow, is over 10 metres deep at some places. The mire area is more than ten kilometres long, and consists of several raised bogs joint together.
The barren centre parts of raised bogs are several metres higher than the edges, where the turf layer is not as deep as in the middle. The spruce bogs on the edges are more lush, and wetter than the centre. The Sphagnum centres, which grow sparse pines, are a labyrinth of drier hummocks, moist hollows, and puddles with open water.
The Diverse Set of Bird and Insect Species
Torronsuo Mire with its surrounding forests is, for many birds, an important nesting area and stopping place during the migration. During the spring and autumn, large flocks of migrating Cranes (Grus grus) can be seen on the mire. The puddles are popular with water birds and waders. In the willow thickets on the edges of the mire lives a Willow Grouse (Lagopus lagopus) population which is one of the southernmost in Finland.
The set of bird and insect species on the large mire area also includes northern species. The Northern Grizzled Skipper (Pyrgus centaureae), the Freija´s Fritillary (Boloria freija) and the Frigga's Fritillary (Clossiana frigga) are beautiful butterflies flying on the raised bog. In other part of Finland they have disappeared or become rare, because mires there have been drained, but on Torronsuo they have found a haven. Sometimes even the Northern Pintail (Anas acuta), the Great Grey Shrike (Lanius excubitor) and the Ruff (Philomachus pugnax), all of which are northern birds, nest in the area. The Eurasian Golden Plover (Pluvialis apricaria), most of which live in the north, is quite abundant on Torronsuo Mire.
Lake Talpianjärvi, which is located near the National Park, is known for its dense Spotted Crake (Porzana porzana) population. It is a flood meadow created by draining the lake. This bird haven will gradually become a part of the National Park.
The Plants of the Raised Bog
The set of mire plant species on Torronsuo is quite diverse. The basic plants of raised bogs are abundant: the Heather (Calluna vulgaris), the Marsh Tea (Ledum palustre), the Bog Bilberry (Vaccinium uliginosum), the Crowberry (Empetrum Nigrum), the Cranberry (Oxycoccus quadripetalus), the Bog Sedge (Carex limosa) and the Rannoch-rush (Scheuchzeria palustris). At some places the vegetation of the islands on the mire resembles herb-rich forest, quite opposite to the barren raised bog. For example on Kiljamo island, the Hepatica (Hepatica nobilis) and the Spring Sweetpea (Lathyrus vernus) flower in the spring. The woody plants of the islands which are typical for herb-rich forests include the Littleleaf Linden (Tilia cordata) and the Fly Honeysuckle (Lonicera xylosteum). The emblem plant of the National Park is the Cranberry (Oxycoccus quadripetalus).
Famous Quartz Deposit
Torronsuo area has been well-known for its quartz deposit since the 1700s, and for its rare minerals, such as pegmatite, since the beginning of the 1800s. Of the 60 pegmatite minerals found in the area, 15 were found in Finland for the first time. Sukulatite, named after the village of Sukula, was found in the area for the first time in the world. In 1862, the famous arctic explorer A. E. Nordenskiöld made an expedition to Torronsuo area to study its tantalum mineral deposits. Almost all of the first tantalum mineral samples in the European museums originate from this expedition.