Conclusions

Eero Tikkanen

The immense emissions of pollutants and cases of damage to the environment in the Kola Peninsula were revealed to the Finnish public in the late 1980s. The concurrent incidents of needle loss by coniferous trees in Finnish Lapland and forest damage in Salla, eastern Finnish Lapland, provided grounds for suspecting some connection between these and the emissions from the Kola Peninsula. News of the damage to the environment in the Kola Peninsula and of the forest damage in Lapland began to worry forest owners and other concerned citizens. Demands began to be expressed for research efforts to be directed at determining the causes of the damage and for restrictions to be imposed on the emissions from the Kola Peninsula. The results provided by the national HAPRO project on acidification proved to be insufficient in regard to Lapland; the project's final report contains a proposal for further research focusing on Lapland and the Kola Peninsula (Kauppi et al. 1990, Kenttämies 1991).

A joint, five-year project, the Lapland Forest Damage Project, participated in by four universities and five research institutes, was launched in May 1989 at the initiative of the Finnish Forest Research Institute (METLA). The project's primary goal was to report on the impact of the emissions of pollutants from the Kola Peninsula on the forests of Finnish Lapland. Secondly, the project endeavoured to pinpoint and delimit the areas of forest damage in the Kola Peninsula. The third goal was to produce basic scientific knowledge on the environment in Lapland and the changes taking place in it.

The METLA established an extensive, line-based sample plot system covering all of Finnish Lapland and part of the Kola Peninsula. The sample plots were located in dry and dryish heathland forests, which were assumed to be sites sensitive to acidification. The results of watercourse studies conducted by the Lapland Water and Environment District gave reason to suspect that acidification may also be threatening the forests of Lapland (Kinnunen 1990, 1992). All the field measurements and collecting of data for laboratory analyses were concentrated on common forest stand sample plots. A station for recording air quality, important from the point of view of the project, went into operation in Sevettijärvi (Inari) in 1991 (Figs. 81 and 82).

Air quality and deposition

Sulphur dioxide and heavy metals

The most typical characteristic of the pollution climate in Finnish Lapland is in the occasional rises in the concentrations of atmospheric sulphur dioxide to fairly high levels when the winds blow from the north-east or east, where the Kola Peninsula's industrial centres lie. This is to be observed in the eastern parts of Inari and in parts of eastern Finnish Lapland, where peaks occur at fortnightly intervals on average. The highest concentration of atmospheric sulphur dioxide was recorded at Sevettijärvi in July, 1992, when it was 500 µg/m3. Since then, the highest concentrations there have varied between 150-300 µg/m3.

Moreover, the concentrations of nickel and copper in the air rise significantly during north-easterly and easterly winds. The pollution episodes originating from the Kola Peninsula also manifest themselves in the air over western Lapland, but diluted to 1/10th of the concentrations in eastern Lapland. Indeed, western Lapland has the cleanest background air in all of northern Europe.

Despite the occasional concentration peaks, and with the exception of the small part in eastern Inari, the average of estimated atmospheric sulphur dioxide concentration in Finnish Lapland is low. In most of Lapland, the average sulphur dioxide concentration is below 2 µg/m3, with higher values occurring eastwards.

In parts of Inari and eastern Finnish Lapland the influence of sulphur was manifested as changes in the physiology and microscopic structure of epiphytic lichens and in their species composition (Tarhanen et al. 1995). The pollution impact also manifested itself in the form of damage to the microscopic structure of Scots pine needles and increased sulphur, nickel and copper concentrations in the needles and bark (on tree trunks and in the litter) of Scots pine and in mosses (e.g. Raitio 1992, Sutinen & Koivisto 1992, Turunen et al. 1994).

Acidifying deposition

The acidity of the deposition in Lapland is regulated by the sulphuric acid formed from sulphur dioxide. Oxides of nitrogen have little significance in the acidification process. As a whole, the annual acid deposition in Lapland is moderate, around half of that in southern Finland. This is mainly due to the lower precipitation in northern Finland. Moreover, part of the precipitation comes down as snow and sulphur dioxide is not readily bound to it. Since the rains are generally brought in by southerly winds, the proportion of sulphur from the Kola Peninsula in the wet deposition is small. All in all, only a very small fraction of the Kola Peninsula's sulphur dioxide emissions is transported to Lapland as wet deposition.

Atmospheric sulphur dioxide also accumulates on vegetation as dry deposition. The amount of dry deposition is proportional to the concentration of atmospheric sulphur dioxide. Since high concentrations of sulphur dioxide in the Inari region of Lapland occur during the growing season as well, the accumulation of sulphur dioxide can be assumed to have a major role in the region's overall pollution load. Calculations have indicated that over 60% of the sulphur deposition in the Inari region may come down as dry deposition. Norwegian researchers estimate 55-75% of Finnmark's (in northern Norway) sulphur dioxide emissions, originating from the Kola Peninsula, to come down as dry deposition (The Norwegian monitoring... 1986).

There is a possibility that dry deposition of sulphur dioxide will not lead to the acidification of the soil. This is supported by the throughfall measurements made in connection with the Lapland Forest Damage Project. Soil studies have not revealed significant acidification; the only changes observed were in the immediate vicinity of Monchegorsk's Severonikel nickel-copper smelter. The only signs pointing to acidification of the soil in Finnish territory were observed in the eastern parts of Inari, a region affected by pollutant emissions from the Pechenganikel nickel-copper smelters in Nikel and Zapolyarnyy. The acid-rain symptoms observed in the microscopic structure of Scots pine needles north of Lake Inarijärvi may be due to dry deposition on wet surfaces.

Ozone

The concentrations of ozone in the air over Lapland are high, equal to those recorded over southern Finland. Lapland's high, at maximum 100- 150 µg/m3, concentrations of ozone (levels which have demonstrably caused damage to vegetation in experimental conditions) are not caused by pollutant emissions from the Kola Peninsula. The emissions of nitrogen oxides and carbohydrates in this region are insufficient for ozone to be formed. The highest ozone concentrations have been measured in the late spring and beginning of the growing season, times of the year when the airborne pollutants that have accumulated in the atmosphere over the winter begin to form ozone as more and more solar radiation becomes available. Ozone is also transported to Lapland from the industrial centres of Central Europe.

There is but little knowledge available on the disturbances to the metabolism of plants and damage to plant microscopic structure caused by ozone in environmental conditions such as those in Lapland. Comparisons made to data from abroad do, however, indicate that exposure to ozone may damage plant life in Lapland. Damage to microscopic structure indicative of ozone-induced damage and the combined impact of ozone and emissions of pollutants from the Kola Peninsula were, indeed, identified in the cells of needles of Scots pine in Finnish Lapland (Sutinen & Koivisto 1992). There is little information available on the sensitivity of boreal forest flora to ozone. The concentrations used in exposure trials are generally too high for the long-term effects of ozone to be revealed (Väre et al. 1993).

Forest-death area and damage zones

The Monchegorsk forest-death area caused by the emissions of pollutants from Severonikel was mapped using satellite imagery. Zones of visible and non-visible damage were roughly outlined in the Kola Peninsula and Finnish Lapland on the basis of field measurements and field samples. The average of estimated atmospheric sulphur dioxide concentrations, calculated using a model developed as a joint effort between Finnish and Russian scientists for depicting the distribution of emissions from the Kola Peninsula, were used in delimiting the areas (Tuovinen et al. 1993). The said zones were also delimited in the vicinity of Nikel, where field studies could not be done in connection with the Lapland Forest Damage Project.

Forest-death area

The Monchegorsk forest-death area amounts to 40 000-50 000 ha in size. It extends ca. 10 km to the south and ca. 15 km to the north of the town (Fig. 83). The area does not extend very far west because the Monche fells are in that direction. In the east there is Lake Imandra and beyond it the town of Apatity and its industrial plants. The environmental impacts of the various industrial plants combine on the western shore of Lake Imandra. The average of estimated atmospheric sulphur dioxide concentration arrived at within the forest-death area exceeds 40 µg/m3.

Blowing mainly from the south-west and west, the winds carry the majority of Pechenganikel's pollutants to the north-east and east. Located on the timber line, Nikel's damage area is oriented from the south-west to the north-east and it is greater in area than the Monchegorsk forest-death area (Fig. 83). In addition to being influenced by airborne pollution, the size of the damage area has also been affected by an epidemic of autumnal moths (Oporinia autumnata), which denuded mountain birch in the region in the late 1960s.

Inner visible-damage zone

The inner visible-damage zone extends ca. 30 km south and ca. 40 km north of Monchegorsk (Fig. 83). The conifers within this zone show marked defoliation and there are no epiphytic lichens to be seen (Fig. 84). Due to the prevailing southerly and northerly winds and the Monche fells, which rise to over 1 000 m a.s.l., this inner visible-damage zone extends no further than ca. 25 km west of the emission source (Fig. 85). The average of estimated atmospheric sulphur dioxide concentration for the inner damage zone is 15-40 µg/m3.

The inner visible-damage zone surrounding Nikel's forest-death area extends into Svanvik, north-eastern Norway, in the south-west (Fig. 83). Protected by the prevailing winds, Svanvik lies at a distance of only 15 km from Nikel. Since there are very few trees close to the timber line, delimiting the inner visible-damage zone is more difficult in the vicinity of Nikel than in the vicinity of Monchegorsk.

Outer visible-damage zone

The outer visible-damage zone extends to a distance of 50-60 km south and north of Monchegorsk (Fig. 83). The impact of pollution emissions within this zone is manifested as changes in the species composition of the lichen communities and external damage symptoms on the needles of Scots pine (e.g. necrosis in the tips of needles). The pollution effect, taking the form of reduced frost- hardiness of pine needles, slight slowing down of growth of pine, and chemical and microbiological changes in the soil, and reduced size of pine root systems, ceases to apply within the outer visible-damage zone (e.g. Lindroos et al. 1995, Sutinen 1995). The same applies to the effect manifested as changes in the amount and composition of the litter (Merilä & Jukola-Sulonen 1995). The marked eroding of the surface wax of pine needles extends to this zone. The average of estimated atmospheric sulphur dioxide concentration within the zone is 8- 15 µg/m3 and the deposition figures for heavy metals are high.

The outer visible-damage zone in Nikel extends into Finnish territory, to the eastern parts of Inari (Fig. 83). The combined area covered by the two types of damage zones surrounding Monchegorsk and Nikel is estimated to amount to 39 000 km2.

Inner non-visible-damage zone

The inner non-visible-damage zone extends into Finnish territory, to northern Salla and eastern Inari (Fig. 83). Chlorosis of the stomata of pine needles is the visible needle-damage symptom manifested within this zone. The pollution effects of risen concentrations of sulphur, nickel and copper in pine needles, bark and mosses terminate within the inner non-visible- damage zone (e.g. Raitio 1992). The same applies to the pollution effects manifested as changes in the species composition of epiphytic lichens and in the physiological functions of lichens (Tarhanen et al. 1995). The effect of premature needle loss by pine terminates within Russian territory (Salemaa et al. 1992). The occurrence of occasional peaks in the concentrations of atmospheric sulphur dioxide terminates in Finnish territory within this zone. The average of estimated atmospheric sulphur dioxide concentration for the inner non-visible-damage zone varies between 4-8 µg/m3.

Outer non-visible-damage zone

The outer non-visible-damage zone, entirely in Finnish territory, extends from the western parts of Inari to Salla (Fig. 83). The impacts of pollution within the zone are slight and local in character. They are manifested as changes in the microscopic structure of pine needles and epiphytic lichens, and as risen conductivity and decreased pH values of the bark (Poikolainen 1992). Chlorosis of pine needle stomata occurs in places. The average of estimated atmospheric sulphur dioxide concentration for the zone varies between 2-4 µg/m3.

The effects of local emission sources (of Kemijärvi, Sodankylä, Rovaniemi and the Kemi-Tornio region) are manifested beyond the outer non-visible-damage zone; e.g. in pine needles and epiphytic lichens.

Damage process

Growth studies have revealed that the death of Scots pine in the Monchegorsk region began in the early 1950s. Tree death was preceded by progressively decreasing growth vigour and its eventual termination. With their growth at standstill, the trees may have remained alive for some years. Studies show that the forest-death area has steadily expanded and continues to do so. Tree growth has ceased and trees have died during unfavourable growing seasons, especially when the temperatures have been abnormally low.

Pollution stress

The concentration of atmospheric sulphur dioxide over the vicinity of Monchegorsk can occasionally exceed 10 000 µg/m3. Sulphur causes damage to foliar tissues, affects the metabolism of trees, and accelerates their decline and eventual death. The pollution load also increases the sulphur concentration in the humus in the Monchegorsk area.

The majority of Severonikel's emissions of heavy metals is deposited within a radius of 40 km from the smelter. Similar observations have been made in the surroundings of the Sudbury nickel-copper smelters in Canada (Hutchinson & Whitby 1974). Heavy metals play a decisive role in the Monchegorsk region's forest-death phenomenon. Metal cations invade the exchange places of base cations (e.g. Ca2+, Mg2+ and K+) on the surface of soil particles. As a result, the soil's base saturation degree and the amount of base nutrients decrease. These in turn hinder the uptake of nutrients by plants and lead to nutrient deficiency. The magnesium concentrations in the pine needles in the area are especially low (Raitio 1992).

Heavy metals also promote forest death in the Monchegorsk region by damaging the roots of trees and by inhibiting the activity of soil microbes. Inhibition of microbial activity slows down the cycling of nutrients and reduces their availability to plants. Damage to the root systems also hinders the uptake of nutrients by plants.

There is little knowledge about the damage caused by heavy metals to the above-ground parts of plants. The concentrations of heavy metals in the foliage seldom have time to reach toxic levels.

Natural stress factors

The manifestation of damage due to pollution and the actual death of plants are often promoted by powerful natural stress factors. The foremost stress factors in boreal ecosystems are connected to climate. In the case of the vicinity of Monchegorsk, for instance, the death of trees was at its most pronounced in the 1960s, a decade of particularly unfavourable weather. The frost-hardiness of pine needles has been reduced in the vicinity of Monchegorsk to a distance of over 30 km from the Severonikel smelter (Sutinen 1995).

The accumulation of airborne pollutants on the above-ground parts of plants causes frost- hardiness-reducing changes in cell structure and functions. The late winter is the most critical time of the year because the diurnal variation in temperature is at its maximum then. Reduced frost-hardiness in plants is accompanied by reduced drought-resistance. The drought stress can also have a serious impact on plants in the late winter.

The damage process in Monchegorsk

The results of studies delving into the growth of Scot pine give grounds for concluding that forest death in the Monchegorsk region will continue to advance at the annual rate of ca. 0.5 km. The highest concentrations of atmospheric sulphur dioxide and the maximum deposition of heavy metals occur within the forest-death area and the inner visible-damage zone, whose boundary is estimated to advance in pace with the boundary of the forest-death area. South of Monchegorsk, especially the inner visible-damage zone has expanded in the course of this project.

' The results of growth studies and interpretation of the satellite imagery indicated that the forest-death area and the inner visible- damage zone expand in patches, not as a contiguous front (Mikkola 1995). The manifestation of the various forms of damage is influenced by natural factors; e.g. climate and site (plants in moist depressions endure pollution loads longer than plants at higher elevations).

The soil of the forest-death areas has been badly spoiled and erosion causes further damage on slopes. The accumulation of heavy metals in the soil is an important damage factor. It will take a long time for the ecosystems to recuperate even if emissions were to be reduced or even cease for the most part (Hutchinson 1980). The good news is that the further spread of the damage would be halted.

State of health of Lapland's forests

The studies conducted within the framework of this project did not indicate a direct connection between the emissions of pollutants from the Kola Peninsula and the incidents of forest damage observed in Finnish Lapland in the late 1980s. The primary reason for the marked premature shedding of needles during the summer of 1987 is believed to be nutrient deficiency caused by root damage resulting from the abnormal conditions of the winter of 1986-1987 (Tikkanen & Raitio 1990a, 1990b, 1990/91, 1993). Forest damage in northern Salla is attributed to top dieback caused by the Scleroderris canker fungus (Gremmeniella abietina) (Kaitera & Jalkanen 1992, 1994a, 1994b, 1995a, 1995b, Kaitera et al. 1995a, 1995b). The occurrence of the Scleroderris canker was not found to be connected to air pollution. Needle loss by Scots pine, especially in the Inari region of Finnish Lapland, has varied from year to year without any distinct trends (Lindgren & Salemaa 1994). Studies employing the needle-trace method and long-term monitoring of pine needle litter indicate that there is great year-to-year variation in the number of needle year classes carried by Scots pine. This variation is mainly due to changes in the macro-climate (Jalkanen 1995a, 1995b, Jalkanen et al. 1995).

The results of studies conducted in eastern Lapland indicate that the soil's microbial activity has diminished. The reason for this was found to be in the wearing out of the lichen layer because of grazing by reindeer. The ungrazed stands of pine in the Kola Peninsula are covered by a thick layer of lichens beyond the outer visible-damage zone. This protective layer is missing in Finnish Lapland (Väre at al. 1995). The layer of lichens evens out the soil's temperature and moisture conditions, promotes microbial activity in the soil, and most probably it also has a positive influence on the nutrient status of the soil and the frost- hardiness of roots. The marked eroding of the surface waxes of pine needles in eastern and northern Lapland may also be connected to the wearing away of the lichen layer.

In the course of the project, the researchers' attention was drawn from northern Salla to the Inari region of Finnish Lapland, which is closer to the Kola Peninsula emissions. Due to its greater pollution load and more northerly location, the forests of the Inari region are under greater threat. The effects of pollution are more numerous in the eastern parts of Inari. Finland's highest concentrations of atmospheric sulphur dioxide have been measured here and the region's copper and nickel depositions are higher than anywhere else in Finnish Lapland.

The vitality of the forests in Finnish Lapland is subject to variation: the needle-loss symptom of the late 1980s has receded, but the weather conditions of the early 1990s suggest that the Scleroderris canker fungus cause increasing damage in the near future. Pine sawflies (Neodiprion sertifer) cause local damage in areas such as the Saariselkä fells (Fig. 86). Autumnal moth (Oporinia autumnata), an insect that caused severe damage to mountain birch in the 1960s in Lapland, has reappeared and caused damage in several places in western and central Lapland (Jalkanen & Nikula 1993) (Fig. 87). Only a small area in eastern Inari is under direct and immediate threat of being damaged by pollution. Apart from this, the emissions from the Kola Peninsula are not expected to cause significant damage to forests in Finnish territory.

The emissions of pollutants from the Kola Peninsula represent a stress factor for forests in Finnish, Norwegian and Russian Lapland, and for the arctic ecosystems in general (Nenonen 1991). The vicinities of the industrial centres in the Kola Peninsula are among the world's most polluted areas (Sulphur 1994). Arctic ecosystems with their few species are highly sensitive to disturbances. Pollution loads that have accumulated there over the years inevitably lead to the toppling of the ecological balance that has evolved over the millennia. The required reduction in emissions can be realised only through the refurbishing of the Kola Peninsula's metal smelters.