Natural Features of Päijänne National Park

Rich geological heritage

The Päijänne National Park is extremely important in terms of its geological value and is a fascinating destination. Some of the park’s numerous islands are elongated esker ranges with sandy shores, while others are made of rock and moraine typical of Päijänne’s rocky hill terrain. The oldest parts of the rock islands were formed nearly two billion years ago, while the esker islands were not formed until the end of the last Ice Age, approximately 11,000 years ago.

The countless rock and esker islands in south Päijänne are emblematic of the landscape. Particularly the esker island chain between Hinttolanselkä and Tehinselkä is an extensive and important part of the park landscape. The most impressive esker island in the 8-kilometre long chain is Kelvenne, which rises as high as 40 metres above the surface of Lake Päijänne. The esker islands, such as Kelvenne, were formed by the gravel accumulated and sifted by glacial flows as the continental ice sheet retreated slowly to the northwest. The deep kettle holes formed next to the islands are remnants of enormous blocks of ice that had become trapped in the sand and slowly melted there, leaving behind cone-shaped holes. 

The Päijänne National Park is one of the most important sites in the Salpausselkä Geopark. The eskers in particular represent the internationally valuable geological heritage of the park. Read more about the Salpausselkä Geopark.

The island of Kelvenne, the heart of the National Park

The island of Kelvenne, the heart of the National Park, is one of Finland’s largest and most beautiful esker islands. The history of its formation and its flora make it one of the most interesting sites in the area. The Kelvenne esker formation comprises a continuum of islands and underwater ridges that stretches from Kelvenne Island to the south and north.

Another typical feature of the area are the deep, sheltered kettle hole bays, such as Koukunlahti, Karhunkämmen and Nimetön, which were formed next to the esker islands. Because many of the kettle hole bays are more than 10 metres deep at their centre and have a shallow threshold that isolates them from the water circulating in the open reaches of the lake, the exchange of water between the bays and wider lake can be minimal. In kettle hole bays like this the groundwater can stay exceptionally cool, even in the summer heat.

As a hiking destination, Kelvenne is truly a natural treasure trove. On the island, hikers will find, among other things, crystal clear water, lovely sand beaches, a wide range of flora in lush esker groves, and the beautiful, lagoon-like kettle bays, which offer not only stunning scenery, but also sheltered natural harbours for boaters. One of the island’s unique features is a deep kettle hole pond, Kelvenneenlampi, which is tucked away in the middle of the island. The vegetation surrounding the pond is quite lush and varied, offering a safe habitat for the little perch living there.

Another important and well-known feature of the park is the chain of esker islands, Pulkkilanharju, which serves as the southeast gateway to the park. Part of Päijätsalo Island also falls within the park boundaries. The highest point on the island offers spectacular views over Lake Päijänne’s largest expanse, Tehinselkä. The largest rock islands are Iso Lammassaari and Haukkasalo. Their sheer, rocky shorelines stand out starkly against the park’s esker landscape. For example, the rock faces of Haukkasalo jut tens of metres straight up from the surface of Lake Päijänne.

Wide range of flora

The natural features of the islands are made up of esker forests, pristine forests and groves and the broad spectrum of flora found within them. The most verdant forests--dry herb-rich groves--are found along the tops of the eskers, because the nutrients in the soil there has not been washed away by water. The understory vegetation includes numerous vascular plants, such as the endangered Bird’s-nest orchid, which grows in small patches. 

On the slopes of Kelvenne, the ancient beach embankments circle round the esker at the altitude contour of about a hundred metres. Below that line grow rugged dry pine forests, typical for esker landscape. Before the National Park was established, the forests were in commercial use, which is why the tree stand is even-aged. However, the set of esker plant species is still impressive. In the middle of Lingonberries (Vaccinium vitis-idaea) and Reindeer lichen (Cladonia rangiferina) flower the Pale-green wintergreen (Pyrola chlorantha) and the Umbellate Wintergreen (Chimaphila umbellata). There also glow the yellow Spotted Cat´s-ear (Hypochoeris maculata) and the blue groups of Harebells (Campanula rotundifolia). The Common cow-wheat (Melampyrum pratense) is a typical plant for dry forests, and its yellow flowers dominate the lower slopes of the eskers in July and August.

Kelvenne’s dry, herb-rich groves are dominated by pine or spruce, while deciduous stands are made up of birch, aspen and littleleaf linden, which can be quite abundant in some places. On the ground of the herb-rich forests flower the Hepatica (Hepatica nobilis), the Lily-of-the-Valley (Convallaria majalis) and the Wild Strawberry (Fragaria vesca), around the Fly Honeysuckle (Lonicera xylosteum) and the Mountain currant (Ribes alpinum) bushes. The abundance of vetchlings (Lathyrus) and vetches (Vicia) is striking. Here and there you can see the beautiful Cinnamon Rose (Rosa majalis), the charming red Mezereon (Daphne mezereum) or the Herb-Paris (Paris quadrifolia), which lives in the shade.

In many kettle holes in the esker on Kelvenne Island, the ground in the bottom has become swampy. One of the holes has turned into a small lake. Despite a few small open fens, the mires are small pine bogs, where the air is fragrant with the stunning scent of the white flowering Marsh tea (Ledum palustre). 

Birds of every feather

The Päijänne National Park is home to numerous bird species, whose habitats include large lakes, shorelines, old-growth forests and groves. The park is vital to the conservation of bird populations, as it serves as the nesting grounds for many species. Small islands and skerries are especially important to the preservation of bird populations, because several endangered bird species use them as nesting grounds.

Various gulls, the Common tern (Sterna hirundo), Red-throated loon (Gavia stellata), Horned grebe (Podiceps auritus), Red-breasted merganser (Mergus serrator) and Common merganser (Mergus merganser), Merlin (Falco columbarius) and Eurasian hobby  (Falco subbuteo) are some of the species nesting in the area. Although the Black-throated loon (Gavia arctica) is quite common in the park, it rarely nests here due to harassment.  Some of the bird species found on forested islands include the Wood warbler (Phylloscopus sibilatrix), Eurasian golden oriole (Oriolus oriolus), European nightjar (Caprimulgus europaeus) and Red-breasted flycatcher (Ficedula parva).

Our large, magnificent diurnal bird of prey, the Osprey (Pandion haliaetus), also known as the Fish hawk, nests on the park’s islands in small numbers. It can be seen fishing on the lake or scanning its territory from its twig nest on the top of an old pine. Because there are so few suitable nesting sites for osprey, numerous artificial nests have been built in the area to ensure their nesting. Like other bird species, the osprey needs nesting protection, which is why some of the park islands are closed to landing and visiting from 15 April to 31 July.

The lesser black-backed gull at Päijänne

The emblem species of the National Park is the Lesser Black-backed Gull (Larus fuscus). The subspecies Larus fuscus is said to be the most Finnish bird, because the majority of them live inside the Finnish borders. The Lesser Black-backed gull, which thrives on large lakes such as Päijänne, is currently listed as being vulnerable to extinction.

Fortunately, visitors to the park can still admire these black-and-white gulls gliding across the summer sky, even though their numbers have fallen considerably. There are several reasons for this decline in population, the biggest of which is the low reproduction rate. The Lesser Black-backed gull is affected by inexplicable reproduction difficulties. Birds do not nest at all, and if the nest is built, the eggs may not be incubated and the chicks may not be fed. In addition to this, the European herring gull (Larus argentatus), which has a higher reproduction rate and is a competitor species, has taken over habitats on large lakes and skerries, thus displacing the Lesser Black-backed gull. 

Under the surface at Päijänne

The Päijänne National Park also offers a wealth of fascinating natural sights under the water. One of the park’s most interesting underwater features is the esker island of Kelvenne and its associated ridges, which run partially submerged all the way to Tupasaari Island in the north and Ykskoivu Island in the south. 

In addition to the clearly defined features of the eskers, the underwater geological formations include austere sand and rock beaches, beautiful underwater kettle holes and, particularly on rock islands, impressive underwater cliffs and crevices. For example, the sheer rock faces on Haukkasalo Island continue almost vertically to depths of more than ten metres in Lake Päijänne. The shadows of the rock faces and the glimmering sunlight of the surface create wonderful contrasts in the underwater landscape.  

The crystal clear Lake Päijänne is a barren lake, which is classified as being an oligotrophic isoetid lake. Significant isoetid vegetation, such as the Alternate water-milfoil (Myriophyllum alterniflorum) and Lake quillwort (Isoetes lacustris), grow along the shoreline of Kelvanne Island, at a depth of approximately 1-3 metres. Roundish stones and boulders worn down by the water offer surfaces for aquatic plant roots as well as small fish and crayfish.

Peek into the underwater nature of Päijänne: