Winter life in the forests of Koli National Park

Winter, with its permanent snow cover, usually arrives in Koli National Park around mid-November, and the snow cover can stay, much to the joy of winter enthusiasts, until May. In good winters, there can be as much as a metre of snow, and Koli is the southernmost place in Finland where also crown snow-load occurs every year. Crown snow-load, the tick accumulation of snow and ice on trees, only occurs when air pressure and temperature are favourable: only then the moisture in the air will sublime directly into ice on trees and on the surface of other structures, too. The ice and snow accumulate all around the tree, that's why there is snow and ice on the trunk and underside of branches, too. The weight of crown snow-load can be several tons, which results in a strange sight on the highest hills of Koli: most of the tree tops are broken at the same height. The latest serious crown snow-load damage was in late winter 2018, when it was necessary to forbid to enter the highest peaks of Koli. Who would want tons of snow or a whole spruce on their necks during a forest trip! Stunning crow snow-load covered forest scenery can be enjoyed in Koli usually from December to early March.

You can explore the winter landscape for example on snowshoes, which is one of the most popular winter activities in the National Park. Thick snow cover brings with it a new kind of freedom: during snow cover you can venture outside the marked trails without worrying about damaging the vegetation - as long as you remember not to brake branches as you go along.

In winter you can, besides admiring the views, also observe animal habits and tracks. Indeed, the National Park's diverse old-growth forests provide ideal habitats for many animals such as the red squirrel (Sciurus vulgaris), the hare (Lepus timidus), the stoat (Mustela erminea), the European pine marten (Martes martes), the European badger (Meles meles), and the elk (Alces alces). In the mornings, fresh tracks of smaller mammals can be found even on the highest peaks of Koli. In less visited areas of the park you can also find depressions on the snow where elks have slept. The badger, also known as earth big or earth dog, hibernates through the winter just like the bear. The badger usually shares the same den peacefully with its fellow badgers. However, badger’s tracks can also be found in winter, as it sleeps lighter than the bear. On mild days, it may emerge from the den to sniff the air or to explore the neighbourhood of its den.

In addition to the bear, all other large land carnivores living in Finland are also found in Koli National Park. Most of them reside in the southern parts of the park, away from the most used snowshoe trails. On the peaceful hills in the south of the park you can come across the tracks left by a nocturnal wolverine. The wolf is a less common visitor in the park. Sometimes it wanders across the lake from the eastern forests of Pielinen area to visit the national landscape of Koli. The tracks of the lynx, however, can be found even near the highest peaks of Koli: the old spruce forests and the steep, rugged rocky eastern hillside of Koli are their favourite habitats.

The old forests of the park with their decaying and fallen trees provide invaluable shelter, food and nesting places for winter birds. In addition to the usual tits (Parus), you can see the goldcrests (Regulus regulus) hanging around with the tits, the crossbills (Loxia) looking for seeds, the sparrows (Passer domesticus), the common redpolls (Acanthis flammea), and many others – depending on the weather and severity of the winter. In addition to the most common woodpecker in the park, the great spotted woodpecker (Dendrocopos major), the three-toed woodpecker (Picoides tridactylus) and the black woodpecker (Dryocopus martius) can be heard drumming in the park and the less common white-backed woodpecker (Dendrocopos leucotos) can also sometimes be seen. There are also many grouse species in the park, so snow burrows made by birds are not an uncommon sight.

One distinctive, although extremely rare, inhabitant of Koli National Park is the northern crested newt (Triturus cristatus). It overwinters in hibernation somewhere near its breeding pond, so it cannot be seen in winter. It is not until in April that the northern crested newts wake up and go to breed in the small ponds surrounded by forest, where no fish live.

Interested in large carnivores? For those interested in the life of large carnivores, there is a lot of interesting information to explore, for example information on the behaviour of the species, snow tracks, history, and much more at www.largecarnivores.fi/. In Kuhmo visitors can find more information about carnivores in the Kuhmo Visitor Centre Petola.

Text / Emilia Kolehmainen
Photos / Stoat: Marko Haapalehto, tracks of wolverine: Tuuli Turunen, wolverine: Aku Ahlholm