Suomen Luonto
English summaries 1/2001

Common reed proudly holds its head high
By Timo Nieminen
Pages 4-11

The common reed (Phragmitis communis) is an attractive plant which dominates the scenery all year round. This, Finland's largest grass, prefers shallow, soft-bottomed, eutrophic shores to grow on. It is also found on bogs and mires, in ditches and along roadsides, where its colonies represent relics from shores that dried out long ago.

Fast-growing common reed is one of southern Finland's commonest shore plants. With the help of its sturdy rhizome, it is able to form dense growths preventing other plants from colonising the shore. These thick reed beds have become extremely profuse over the last half century or so. The main reason for this is lake eutrophication. Secondly, the modern absence of grazing along the shores has had an impact since cattle were instrumental in keeping the reeds in check.

Finns often incorrectly call the common reed ìkaislaî, which in fact is the common name for some members of the Scirpus genus. In late summer the common reed produces spectacular blooms with a violet tinge. It dries out in autumn, after which the tough, tall stems remain erect above the snow. The seeds ripen in midwinter and are distributed by wind to new potential growing sites.

Common reed beds provide an ideal habitat for a wide variety of animals, including sedge warblers, great reed warblers and reed warblers, as well as insects. In winter, bluetits and harvest mice feed on the seeds.

The fast-growing reed has long been used to benefit people. Buildings have been roofed with the material, it has been spread on floors as mats, and the downy seed heads have provided a soft stuffing for mattresses and pillows.

Waxwings have some secret habits
By Lasse J. Laine
Pages 30-35

A good rowan, or mountain ash, berry year means a change in their life style for many species of birds. Attracted by the profusion of berries, some fieldfares and blackbirds spend their entire winter in Finland instead of flying south. Bullfinches, starlings, pine grosbeaks, and many other birds also make use of rowan berries. However, the waxwing is indisputably the rowan tree's number one friend.

In summer, waxwings hide away in the boreal coniferous forest, appearing in the autumn as flocks. At that point in time, they either migrate south, or remain in large numbers to feast on the rowan berries. At first the birds consume the berries hanging in the forests, but later they come into yards, gardens and even into the parks of large cities, after the red berries.

All too often, waxwings fly against a window, with fatal consequences. Since olden times it has been averred that waxwings get drunk on fermented rowan berries and for this reason they blunder into the glass! It is true that the sugar in the berries partially ferments as the autumn progresses, producing ethanol. A waxwing may consume its own weight in berries in the course of a single day. However, the bird does not have a ìboozingî problem; the secret lies in its liver. Waxwings are blessed with ìsuper-liversî which are able to break down 0.1% of alcohol per hour. This would take a person ten times longer (approx. 0.01% every 40 minutes).

Waxwings are denizens of the forests, who do not understand the dangers of the city or other human habitation. They fly straight into reflective windows when frightened by people, a dog, or a hunting sparrow hawk.

The "White Death"
By Juha Valste
Pages 26-29

A strange visitor appeared in a country house kitchen during the winter. Thought at first to be a white mouse, the animal turned out to be a weasel. It developed a habit of searching for food in the kitchen larder throughout the winter. However, it stopped coming in the late winter and in the middle of summer the house owner observed three young weasels behind the stables in the yard. It appeared that the mother weasel had survived until at least the summer.

The weasel is the world's smallest predator. Its closest Finnish relative is the stoat. Officially protected as a species, the weasel is common in Finland, although its populations fluctuate wildly according to the vole situation. When there are many voles to prey on, weasels stay healthy and produce large litters. After the vole populations crash, there follows a cataclysmic decline in the weasel populations in the characteristic predator/prey scenario.

Central European weasels are larger than their Finnish cousins and they also have longer tails. They belong in fact to a different subspecies. Weasels generally mate in spring. However, litters have been found in Finland at almost any time of year, due to delayed gestation. The better the vole year the larger the litters. These vary in size from just a few young to as many as ten individuals. The mother looks after her young for over two months. Males play no part in the care of their offspring.

Young weasels play together and with their mother almost constantly, learning in this way to hunt and avoid enemies. As their wild play gradually becomes more serious, the family splits up. Inexperienced young weasels easily fall prey to larger predators, their worse enemies being owls.

In relation to its size, the weasel is a ferocious carnivore, capable of attacking animals, like water voles, much larger than itself. Weasels have a hard time in winter, when ìcold-bloodedî animals are hibernating and most birds are away in the south. If no small mammals are to be found, many weasels die of starvation as the winter progresses.

Bring the forests back!
By Alice Karsson
Pages 20-24

The forest has always been the Finnish countryman's bank. Nowadays, the most common method of going to this bank is to make stumpage deals. This means that the seller gives the buyer the right to fell the standing trees and extract them from the forest. In this way, wallet-filling money is in the seller's bank within a matter of weeks. In a stumpage deal, the company's power is elevated. Such deals suit the wood industry because the mills desire an uninterrupted flow of timber. Harvesting with heavy machinery when the ground is not frozen and thus soft damages tree roots and may cause decay.

Forest owner Samuli Nissi, from Jokikunta in Vihti (near Helsinki), handles his bank affairs in a more leisurely manner. The decision to make the final cut (regeneration cut) is gradually reached over the course of a year. Nissi knows his forest backwards and remembers where there are trees ready for cutting, or windblown trees requiring removal. He does the forest work himself with the ground frozen hard in winter, using a chain saw and agricultural tractor, without damaging the forest.

Highly mechanised, efficient forestry came to Finland from Europe after World War II. Since then Finland has incredibly rapidly become a country of what are laconically called ìtree fieldsî (comparable to corn fields). Bad points of this kind of forest management include clearfelling, low thinning, nitrogen fertilisation, and a desire for fast growth. ìLow thinningî means that small trees are cut and larger ones are retained. According to Nissi, however, the latter often have too many branches (showing up later as knots) and are of generally inferior quality. A genetically selected tree that has been artificially fertilised with nitrogen is prone to damage by storms and frost, as well as by pests.

The purpose of Pro-Silva Europe (The Association of European Foresters Practising Forest Management Which Follows Natural Processes), established in 1989, is to re-populate Europe with natural, genetically variable forests. In Finland, modern commercial forest management has been challenged by natural forest management ideals, promoted by The Association for Sustainable Forestry. The idea is to retain a composition corresponding to that of a naturally growing forest, even after cutting. The lower vegetation is retained and there is neither clearfelling nor low thinning. For harvesting purposes, light and cheap alternatives are employed, for instance an agricultural tractor or horse.

Forests formed by trees of different species and ages have a variable composition and in general are more healthy than ìtree fieldsî, which support even-aged stands. Another advantage is that the forest remains a forest and the familiar wooded landscape is conserved. On today's clearcuts there will be no real forests until our grandchildren's day.

Czech republic revives its forests
By Teuvo Suominen
Pages 44-45

The landscape could be a moonscape, if it were not for the stark silhouettes of dead standing trees resembling skeletons. This is what greets the visitor to the heart of Europe's acid rain areas in the Erzgebirge mountains on the Czech-German border. In this region, heavy industry based on lignite for several decades was governed by Eastern Europe's ponderous socialist economy and outmoded environmental policy.

The ticking time bomb finally went off in the 1960s, when forests began to die standing. With the winds of political change, however, the amount of acid rain began to decline. Today's situation is that there continues to be too much acid, despite a healthy 80% reduction in sulphur emissions compared to the level during the worst years of acid rain precipitation. Sulphur recovery technology has come to eastern Europe and there is now some confidence in a better situation in the future.

Forest studies are by their very nature slow affairs and there is still no sign of a definite recovery of the ìacid rain forestsî. The Czechs are a persevering race, however. Cuttings have been taken from some of the trees that have survived the pollution and these are now sturdily growing. Silver fir (Abies alba), Colorado, or blue, spruce (Picea pungens) and birch (Betula) have been successfully planted in open ground on trial plots. Despite liming, the soil unfortunately remains depressingly acid. Other problems include magnesium deficiency.

Teksti: Leigh Plester