Suomen Luonto
English summaries 8/2001

Forest path
By Heikki Kirstinä
Pages 4-9

A forest path results from human footsteps and tell us about people\'s daily needs, past and present. Such paths have their own mind. As long as the wanderer obeys its wishes, the path will reward him or her. The imagination populates the path, bringing people out of the past, and their work and leisure, to it. Nowadays a path can be cheated, made part of a clearcut or a thinning operation where it is impossible for people to walk. If, after a desperate search, one finds a new path, this broadens, becomes a logging road and ends suddenly in a modern metalled road.

Strange chambers
By Juho Rahkonen
Pages 16-17

The Italian word \"tafone\" means a boulder that has been hollowed out. This word has been corrupted to \"tafoni\" in Finnish. Around 300 such entities have been discovered in Finland, located at 50 different places in various parts of the country. In the past, boulders of this type were regarded with awe and suspicion, acquiring folk names like \"The Devil\'s stone\" and \"The Devil\'s oven\". The Ancient Finns used hollow rocks as sacrificial sites, taking grain, bread and meat to them. Finland \'s most famous example is at Inari. Known as \"The bear\'s lair stone\", it requires no stretch of the imagination to realise what it was regarded as.

Hollow boulders of this kind originate as a result of disintegration due to physical weathering. Starting with a tiny hollow in the side of the rock, a hole can gradually expand to the size of a living room. Most of Finland\'s examples were formed during the Ice Age, but the holes in them continue to grow larger as time goes on. This is because water condensing out of the air on to the surface of the rock eventually freezes and as the ice expands it breaks up the material.

Grateful flowers
By Jani Kaaro
Pages 18-21

Honey bees, bumblebees and flowers have a long common history. Flowers produce nectar and pollen, which are eaten by these insects. At the same time, the bees carry out the vital task (from the plant\'s point of view) of transferring pollen from one individual to another. The morphology of the flowers and of the honey bees and bumblebees exploiting their nectar and pollen has to coincide. Long, narrow blossoms call either for a long proboscis or for entomological cunning - a bumblebee may carve a hole in the base of the flower, \"lapping up\" the nectar through this. Certain flowers are so specialised that only one species of pollinator is able to perform the desired task. Thus, some species of bumblebee only visit the flowers of a certain plant species. For instance, Bombus consobrinus only visits the flowers of northern wolfsbane (Aconitum septentrionalis).

Honey bees and bumblebees have evolved complicated behavioural patterns in which scents and sight play an important part. Using these two senses, the insects are able to communicate with conspecifics regarding their specific identify, home colony, sex, the food they are using, and the distance and orientation of a food source.

Curing the blues
By Mika Pajari
Pages 24-27

Altogether there are 17 species of \"blues\", butterflies belonging to the family Lycaenidae, in Finland. The biggest of these is the large blue (Maculinea arion), and the tiniest the small blue (Cupido minimus). Both these species inhabit the warm south slopes of ridges, where they survive in habitats kept in check by human impact. In the past, their colonies occurred in dry clearings produced in the forest by fires. Both the species are nowadays endangered. As recently ago as the mid- 1980s the small blue was still relatively common in this country. However, during the 1990s it vanished from many of its known haunts. Small blue habitats tend to be of restricted size, so that they easily suffer from encroachment or earthworks. Now there are only a few colonies left.

The large blue is also very demanding in regard to its habitat. Today it occurs at only two localities in Finland. If the two species are to remain in the Finnish fauna, drastic measures are called for. The habitats soon become overgrown, driving out the butterflies\' low-growing foodplants. Clearing scrub and trees is only effective in the short term. Fire and the almost total removal of the vegetation cover seems to be necessary. Key habitats have already been periodically cleared by volunteers, but in the future robust excavators and bulldozers will be needed as an aid to the conservation work on behalf of these delicate butterflies!

A summer with some geese
By Erkki Makkonen
Pages 30-34

As its name implies, the Canada goose comes from North America. It became established in Finland during the 1970s after introductions, to become the country\'s commonest species of goose. Erkki Makkonen followed the breeding of a pair of Canada geese in the northern part of Lake Saimaa in the summer of 1999. The female built a simple nest on an islet at the beginning of May. She incubated the eggs for a month, the male guarding the nest with exemplary fatherly dedication. The eggs hatched on 6th June. Day-old goslings swam under the watchful eye of their mother away from the islet to the protection of a larger island. They ate grass and aquatic plants ravenously and as a consequence they rapidly put on weight. At seven weeks old they were already able to fly. The goose family remained steadfastly together for the entire late summer period. In October they migrated south.

Around half of Finland\'s Canada goose population overwinters in southern Finland, and the other half in the southern parts of the Baltic. In North America the migratory journeys are much longer, extending from the Hudson Bay to as far as the southern states of the USA. In April or May the goose family returns to its familiar breeding grounds. Then the young geese leave their parents to join individuals of similar age. Canada geese pair up for life, the members of a pair being extremely defensive of their mates.

Gourmet lichens and health promoting fungi
By Marja Härkönen

The Chinese were already using fungi for food and medicines when Finland was still at the prehistoric stage. Botanist Marja Härkönen visited China\'s remote Hunan province gathering data on fungi that has traditionally been passed on by word of mouth. Chinese people consume a lot of wild mushrooms, as well as lichens, which they consider delicious. There may be several edible fungi in the same meal. Mushrooms are first dried, either in the sun or in wood-fired ovens.

Fungi for medicinal purposes are mentioned in old Chinese medicine books as much as two thousand years old. Nowadays mushrooms are still used for curing diseases, as well as for promoting health and vigour. The best and most versatile fungus is the bracket fungus Ganoderma lucidum.

Cases of fungus poisoning occur in Hanan, despite the Chinese being wary of collecting unknown species. The fungi are picked and smelled and, if the sniffer feels slightly faint as a result, the fungus is regarded as being poisonous. Some human fungus guides blew on the gills of Russulas. If this produced a whistling noise, then the fungus was pronounced as fit to eat! The Finnish visitors were also shown the technique - known, too, in Europe - of placing a silver article in some brewing fungi and then watching to see whether the silver goes black as a sign of toxicity. Have we perhaps learned this method from Ancient China?

Teksti: Leigh Plester