Current issue: 54(2)

Under compilation: 54(3)

Impact factor 1.683
5-year impact factor 1.950
Silva Fennica 1926-1997
1990-1997
1980-1989
1970-1979
1960-1969
Acta Forestalia Fennica
1953-1968
1933-1952
1913-1932

Articles containing the keyword 'ants'.

Category: Research article

article id 516, category Research article
Celeste Lacuna-Richman. (2003). Ethnicity and the utilization of non-wood forest products: findings from three Philippine villages. Silva Fennica vol. 37 no. 1 article id 516. https://doi.org/10.14214/sf.516
The utilization and trade of non-wood forest products in three villages in the Philippines were compared in this study. Two villages were situated close to each other on the Island of Palawan. The Tagbanua, an indigenous people, inhabited one village; migrants from the Visayas Region of the Philippines populated the other. The third village is located on the Island of Leyte, in the Visayas Region, populated by native Visayan settlers. There was no significant difference in the number of NWFPs utilized by the indigenous people and the migrants. However, there was a wide disparity in income between the two groups, with migrants earning more, partly due to the marketing of commercial NWFPs. This gap could be decreased by fairer trading practices that are dependent in part on better educational opportunities, land rights, legal assistance and access to markets for the Tagbanua. Specific socioeconomic characteristics, such as the presence of a hunter within the household and size of the family were found to have a positive correlation with the use of NWFPs in some study villages. Income and the food expenditure of the household were inversely related with the use of NWFPs in the native Visayan village.
  • Lacuna-Richman, Faculty of Forestry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail: celeste.lacuna-richman@forest.joensuu.fi (email)

Category: Research note

article id 1321, category Research note
Sofia Bäcklund, Mari T. Jönsson, Joachim Strengbom, Göran Thor. (2015). Composition of functional groups of ground vegetation differ between planted stands of non-native Pinus contorta and native Pinus sylvestris and Picea abies in northern Sweden. Silva Fennica vol. 49 no. 2 article id 1321. https://doi.org/10.14214/sf.1321
Highlights: Differences in ground vegetation patterns can be linked to tree species, forest stand age and differences in canopy cover; Vascular plant cover was higher in stands of P. contorta than in stands of both native tree species; The overall differences and similarities between P. contorta and the two native conifers were not consistent over the different age classes.
Intensified forestry increases the interest in replacing native tree species with fast growing non-native species. However, consequences for native biodiversity and ecosystem functioning are poorly understood. We compared cover and composition of major functional groups of ground vegetation between planted stands of non-native Pinus contorta Dougl. var. latifolia Engelm. and native conifers Pinus sylvestris L. and Picea abies (L.) H. Karst. in northern boreal Sweden. We quantified the ground cover of lichens, bryophytes, vascular plants and ground without vegetation (bare ground) in 96 stands covering three different age classes (15, 30 and 85 years old). Our study revealed differences in ground vegetation patterns between non-native and native managed forests, and that these differences are linked to stand age and differences in canopy cover. Total vascular plant cover increased with increasing stand age for all tree species, with P. contorta stands having higher cover than both native conifers. The ground cover of lichens was, although generally low, highest in stands of Pinus sylvestris. P. abies stands had a lower cover of vascular plants, but bare ground was more common compared with P. contorta. Our results suggest that the use of P. contorta as an alternative tree species in Fennoscandian forestry will influence native ground vegetation patterns. This influence is likely to change with time and future research should consider both temporal and landscape-scale effects from shifting tree-species dominance to Pinus contorta and other non-native tree species.
  • Bäcklund, Department of Ecology, Swedish University of Agricultural Sciences, P.O. Box 7044, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: sofia.backlund@slu.se (email)
  • Jönsson,  The Swedish Species Information Centre, P.O. Box 7007, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: mari.jonsson@slu.se
  • Strengbom, Department of Ecology, Swedish University of Agricultural Sciences, P.O. Box 7044, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: joachim.strengbom@slu.se
  • Thor, Department of Ecology, Swedish University of Agricultural Sciences, P.O. Box 7044, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: goran.thor@slu.se

Category: Article

article id 7150, category Article
Olavi Laiho, Peitsa Mikola. (1964). Studies on the effect of some eradicants on mycorrhizal development in forest nurseries. Acta Forestalia Fennica vol. 77 no. 2 article id 7150. https://doi.org/10.14214/aff.7150

Mycorrhizal association is a characteristic feature of the trees of the northern coniferous forests. The purpose of the present study was to determine what influence some fungicides and herbicides regularly used in Finnish nurseries have on formation and development mycorrhizal in Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) seedlings. The results are based mainly on field experiments in nurseries. First the initiation of mycorrhiza was described in untreated seedlings.

In the first growing season mycorrhizal infection commences fairly late even under normal conditions, i.e. 6–7 weeks after seeding and 3–4 weeks after the formation of the first short roots. Soil disinfectants are commonly used in nurseries before seeding, and they are supposed to evaporate or disintegrate in a few days or 1–2 weeks. In pure culture experiments mycorrhizal fungi proved several times more sensitive than parasitic and indifferent soil moulds to herbicides and fungicides, but in field experiments the delay of mycorrhizal infection caused by them does not seem to harm the seedlings. In the second summer differences of mycorrhizal relations between treated and control plots disappeared. Accordingly, the influence of biocides on mycorrhizae, when applied in the customary concentrations, does not extend beyond the first growing season.

Methyl bromide and SMDC retarded mycorrhiza formation distinctly, while formaldehyde and allyl alcohol had no effect. Apart from not retarding mycorrhizae, formaldehyde and allyl alcohol promoted seedling growth and favoured Trichoderma viride in the soil. Trichoderma is known to be antagonistic to many fungi.

The PDF includes a summary in Finnish.

  • Laiho, ORCID ID:E-mail:
  • Mikola, ORCID ID:E-mail:
article id 7239, category Article
A. Benj. Helander. (1929). Pekkalan kartanon metsätalous. Acta Forestalia Fennica vol. 34 no. 26 article id 7239. https://doi.org/10.14214/aff.7239
English title: Forestry in the Pekkala estate.

The article is a review on the history of forestry in Pekkala estate, a private woodland estate in Ruovesi in Southern Finland. The estate had 7,300 hectares of land in 1929, of which 500 hectares were agricultural lands. It was owned by the Aminoff family since 1822.

The household wood harvesting of the tenants was considered a problem until the farms of the tenants (crofters) became independent in 1921, when the farms of the tenants were parceled out from the main estate. The shifting cultivation of tenants was banned already in 1824. Demand of wood was low until 1870s. in 1865 the freeing of regulation of sawmills increased the demand of wood in Finland, and gave start to significant timber sales in Pekkala estate. The first forest officers were hired in the estate at the time. The first guidelines of forest management for the estate were compiled in 1912, and the first survey of the forests was made in 1916, and repeated in 1922 and 1926. The fellings were planned in consideration of the growth of the forests.

The volume 34 of Acta Forestalia Fennica is a jubileum publication of professor Aimo Kaarlo Cajander. The PDF includes a summary in German.

  • Helander, ORCID ID:E-mail:
article id 7225, category Article
A. E. Osmaston. (1929). On the forest types in India. Acta Forestalia Fennica vol. 34 no. 12 article id 7225. https://doi.org/10.14214/aff.7225

Forest site type classification based on the vegetation has not been developed in India. The classifications made by forest officers have been based on the upper storeys of trees. Shrubs have been used to class such sites where grasses are the dominant species. However, some observers in India have used grass and bamboo species to identify sites suitable on unsuitable for certain valuable tree species. In Burma, some bamboo species have been noticed to be good indicators for sites suitable or unsuitable for teak (Tectona grandis L. f.). Studies in the western sub-Himalayan area suggest that certain grasses could be used as indicators for sites suitable for sal (Shorea robusta Gaertn.). Grasses have also been identified as indicators for certain kinds of forests and soils in the area between Ganges and the Jumna.

The volume 34 of Acta Forestalia Fennica is a jubileum publication of professor Aimo Kaarlo Cajander.

  • Osmaston, ORCID ID:E-mail:
article id 5503, category Article
Juha Heiskanen. (1993). Variation in water retention characteristics of peat growth media used in tree nurseries. Silva Fennica vol. 27 no. 2 article id 5503. https://doi.org/10.14214/sf.a15664

The water retention characteristics and their variation in tree nurseries and related physical properties were determined for commercially produced growth media made of light slightly humified Sphagnum peat. A total of 100 samples of peat media were collected from filled seedling trays in the greenhouses of four Finnish nurseries in 1990. In addition, the physical properties were determined for two growth media made of compressed peat sheets and chips. The variation in water retention characteristics in nurseries was described using linear models with fixed and random effects. The sources of variation in the mixed linear models were producer, grade, batch (greenhouse) and sample (tray).

The water retention of the peat media at different matric potentials was comparable to that given in the literature. The media shrank an average of 0–16% during desorption. The peat grades were finer than the Nordic quality standards for peat growth media. Particles < 1 mm increased and particles 1–5 mm decreased the water retention characteristics measured. The greatest total variation in water retention was at -1 kPa. The water retention of the peat media differed least at -5 and -10 kPa. The water retention characteristics of media from different producers usually differed significantly. The grades, on the other hand, did not differ from each other in their water retention characteristics nor were there significant interactions between producer and grade. The batch effect was marked but was lower than the effect within batches, where the sample (tray) effect was greater than the effect due to random measurement error. At -10 kPa, the measurement error was, however, clearly greater than the sample effect. The random measurement error was comparable to the batch effect. Aeration of the growth media is dependent on the water content retained between saturation and -1 kPa. The water availability to seedlings at the nursery phase is affected mainly by water retention between -1 and -10 kPa.
The PDF includes an abstract in Finnish.

  • Heiskanen, ORCID ID:E-mail:
article id 5406, category Article
Olavi Huuri. (1990). Leikattu paakkutaimi. Silva Fennica vol. 24 no. 1 article id 5406. https://doi.org/10.14214/sf.a15558
English title: The cut-block method for seedling production: birth of an idea.

The author first introduced the cut-block seedling production method to Finland in 1969. The aim is to raise seedlings whose lateral roots do not become deformed as a result of a restricting container or other external pressure. The seedlings are raised in a large, fairly compact substrate block where the roots can freely develop in a normal fashion. The blocks are then cut up into individual cubes, each containing a seedling. The precise positioning of the sowing point permits mechanization of the work.

The PDF includes an abstract in English.

  • Huuri, ORCID ID:E-mail:
article id 5205, category Article
Juha Suominen, Alfred Varkki. (1984). Lauhanvuoren kasvisto. Silva Fennica vol. 18 no. 1 article id 5205. https://doi.org/10.14214/sf.a15384
English title: Vascular plant flora of Lauhavuori Hill, Western Finland.

The Lauhavuori area is barren, consisting of sandstone and granite bedrock covered by coarse moraine and sand. The woodlands are dominated by Scots pine (Pinus sylvestris L.) and Calluna. The top of the hill, rising 230 metres above the sea level, is more fertile, as it was never covered by the ancient Baltic Sea. Numerous springs and spring brooks are bordered by herb-rich Norway spruce (Picea abies (L.) H. Karst.) woodlands and swamps. Although most of the peatlands are oligotrophic, several mesotrophic peatland plants occur, some southern, giving the peatlands a rather northerly character.

The study area is 8 by 12 km. According to the vegetation analysis, 310 species were identified, 208 of which were native to the area and 102 immigrants. The native species can be separated from the immigrants because the area is largely undisturbed.

The PDF includes a summary in English.

  • Suominen, ORCID ID:E-mail:
  • Varkki, ORCID ID:E-mail:
article id 7051, category Article
Mauno Pekkala. (1920). Tutkimuksia kruununmetsätorppien taloudesta Kurun, Parkanon ja Ikaalisten pitäjissä. Acta Forestalia Fennica vol. 17 no. 3 article id 7051. https://doi.org/10.14214/aff.7051
English title: Studies on the economic situation of tenants in the state lands in counties of Kuru, Parkano and Ikaalinen.
English keywords: tenants; state lands; farm; state forests

This study was conducted for the request of state forest committee. The aim was to study the economic situation of tenants of state lands in Kuru, Parkano and Ikaalinen, situated in Central Finland. The chosen 30 farms were located in relatively remote parts of the state forests in the area. Half of the farms were established already in 1800-1860 for shifting cultivation or fishing, and the land was not always suited for farming. The state forests were in general on the poorest lands of the areas. They were relatively small; third of them had less than 2 hectares of agricultural land. Household timber harvesting required a permission from a local forest officer of Metsähallitus (Forest Service). The legal rights of the tenants were fairly secured, but many wished to get right to purchase the farm land. Due to the poor lands and insufficient fertilizing, the crops were lower than in small farms in average. The forests around the farms were mixed forests of poor quality, due to the wood utilization of the tenants.

The PDF includes a summary in German.

  • Pekkala, ORCID ID:E-mail:
article id 5149, category Article
Toini Holopainen. (1981). Alterations in the ultrastructure of epiphytic lichens Hypogymnia physodes and Alectoria capillaris caused by air pollution. Silva Fennica vol. 15 no. 4 article id 5149. https://doi.org/10.14214/sf.a15376

The ultrastructure of Hypogymnia physodes (L.) Nyl. and Alectoria capillaris (Bryoria capillaris (Ach.) Brodo & D. Hawksw.) grown or transplanted near a fertilizer plant and a pulp mill was compared to normal ultrastructure of these lichen species. The ultrastructural changes observed were highly similar in the symbionts of both species and near both the factories although the emissions are different. In the lichens grown near the factories the number of algae had clearly increased. The appearance of the chloroplasts was roundish compared to controls. The pyrenoglobuli and cytoplasmic storage bodies were smaller than normally and the number of polyphosphate bodies had increased. Also, in mycobionts storage droplets were very small or absent and many vacuoles and dark inclusions appeared to hyphae in contrast to controls. In transplanted lichen there existed mainly the same ultrastructural changes as in the lichen grown near factories. Near the fertilizer plant the damage was, however, more severe because all the lichens died during 6–7 months after transplantation. Near the pulp mill part of the lichens survived and seemed to adapt to air pollution.

  • Holopainen, ORCID ID:E-mail:
article id 5145, category Article
Torleif Bramryd. (1981). Environmental effects of heavy metals distributed from power plants. Silva Fennica vol. 15 no. 4 article id 5145. https://doi.org/10.14214/sf.a15372

Increased prices on oil have resulted in the search for alternative energy sources, e.g. coal, peat, biomass, different types of waste. Combustion especially of waste, coal and peat emits large quantities of air pollutants such as heavy metals but also harmful organic substances. Heavy metals are not easily separated from the smoke, and the concentrations are often high in the emissions even with advanced fly-ash separators.

Ecological investigations carried out around a coal burning power plant in Finland using mosses and pine needles as parameters are presented in the paper. Increased concentrations of Pb, Cd, Cr, Ni, Cu and V have been found near the plant. Often a clear gradient was found with increased concentrations at decreased distance from the power plant.

  • Bramryd, ORCID ID:E-mail:
article id 5142, category Article
Lars Moseholm. (1981). Responses of transplanted lichens to sulphur dioxide dosages - a new semi-statistical dosage/injury model. Silva Fennica vol. 15 no. 4 article id 5142. https://doi.org/10.14214/sf.a15369

A semi-statistical model is suggested for monitoring injuries of plants for long-time field exposures (months). The model is based on the following assumptions:

1. The concentrations of air pollutants in the atmosphere follow the Johnson SB distribution.

2. The degree of plant injury is proportional to the logarithm of air pollutant dose.

3. No injuries occur below a certain dose level.

4. A dose is defined as the air pollutant concentration multiplied by the duration of exposure raised to an exponent.

Based on the air pollutant frequency distribution a total dose for the exposure period is calculated by integration, and the total dose is related to the observed plant injury by non-linear regression. The model is tested for long-time exposures of sulphur dioxide to transplant lichen in natural environment.

  • Moseholm, ORCID ID:E-mail:
article id 4907, category Article
Heikki Wuorenrinne. (1974). Suomen kekomuurahaisten (Formica rufa coll.) ekologiasta ja levinneisyydestä. Silva Fennica vol. 8 no. 3 article id 4907. https://doi.org/10.14214/sf.a14751
English title: About the distribution and ecology of Formica rufa -group in Finland.

The paper describes the systematics, distribution, abundance and nest sites of Formica rufa -group in different Finnish forest types. In addition, it has been estimated the availability of Finnish ants in the biological competition.

F. polyctena, F. aquilonia and F. lugubris are distributed over whole Finland. F. rufa and F. nigricans to Southern Finland only. The relative abundace of ant nests diminish to Northern Finland. F. rufa -group prefer most forest on moist land (Myrtillus and Oxalis-Myrtillus types), mixed forests of Norway spruce (Picea abies (L.) H. Karsts), Scots pine (Pinus sylvestris L.) and birch (Betula sp.), and the silvicultural density 0.6–0.7 (good or satisfactory density), but they avoid broadleaved and pure one-tree species forests. For the biological competition the most competitive ant species seem to be F. polyctena and F. aquilonia.

The PDF includes a summary in English.

  • Wuorenrinne, ORCID ID:E-mail:
article id 4907, category Article
Heikki Wuorenrinne. (1974). Suomen kekomuurahaisten (Formica rufa coll.) ekologiasta ja levinneisyydestä. Silva Fennica vol. 8 no. 3 article id 4907. https://doi.org/10.14214/sf.a14751
English title: About the distribution and ecology of Formica rufa -group in Finland.

The paper describes the systematics, distribution, abundance and nest sites of Formica rufa -group in different Finnish forest types. In addition, it has been estimated the availability of Finnish ants in the biological competition.

F. polyctena, F. aquilonia and F. lugubris are distributed over whole Finland. F. rufa and F. nigricans to Southern Finland only. The relative abundace of ant nests diminish to Northern Finland. F. rufa -group prefer most forest on moist land (Myrtillus and Oxalis-Myrtillus types), mixed forests of Norway spruce (Picea abies (L.) H. Karsts), Scots pine (Pinus sylvestris L.) and birch (Betula sp.), and the silvicultural density 0.6–0.7 (good or satisfactory density), but they avoid broadleaved and pure one-tree species forests. For the biological competition the most competitive ant species seem to be F. polyctena and F. aquilonia.

The PDF includes a summary in English.

  • Wuorenrinne, ORCID ID:E-mail:
article id 4844, category Article
Kaarina Rutanen. (1971). Sinivuoren luonnonpuiston kasvisto ja kasvillisuus. Silva Fennica vol. 5 no. 2 article id 4844. https://doi.org/10.14214/sf.a14646
English title: Flora and vegetation of the Sinivuori Nature Park in Southern Finland.

The Sinivuori Nature Park, located in the northeast part of the county of Häme in Southern Finland represents the rare fertile forest lands in the country, and belong partly to the so-called centre of herb‐rich forests of Häme. Sinivuori is one of the smallest nature reserves in Finland (64 ha). The detailed vegetation analysis was performed in 1969, supplemented by earlier and later observations. The area was divided into 69 one-hectare squares for the study of the flora and vegetation.

The most common rock in the park is mica schist. The pH of the soil is relatively high, in average 6.6. Thermal-time sum is 1,100–1,200. The vegetation differs to a large extent from the surrounding areas. 169 vascular plants were found in the area, some of which very rare in the area. The paper lists the plants and their abundance in the area, and the vegetation is described by the forest types. Distribution maps are presented for the species.

The PDF includes a summary in German.

  • Rutanen, ORCID ID:E-mail:
article id 4680, category Article
Pohjois-Suomen uitto-olojen järjestelykomitea. (1959). Pohjois-Suomen uitto-olojen järjestelykomitean mietintö. Silva Fennica no. 102 article id 4680. https://doi.org/10.14214/sf.a14123
English title: Report of the organizing committee for timber floating in Northern Finland.

Hydroelectric plants are being planned or already built in Northern Finland. The complete terracing and regulation of watercourses necessary for the power plants will mean great changes in floating conditions and hence for forestry, for which floating is the principal means of transport. Consequently, the Cabinet appointed a committee in 1958 to ascertain the economic, technical and legislative questions connected with timber transport in the area.

The committee has found that about half of the country’s forest area and two thirds of its water power resources are situated in Northern Finland. A prerequisite for the wise utilization of the forest in Northern Finland is an increase in fellings. This can only be put into effect by improving the means of transport, especially the floating channels. The financing required by the organization of floating connected with the building of the hydroelectric power plants amounts to about 10,000 million marks over a period of 20 years.

The committee has suggested that an advisory committee on floating should be established. Its most important task would be to try to produce a general programme for the organization of floating under the changed conditions, and that the State should participate in the expenditure caused by the organization as regards the capital investment needed for changing over to bundle floating.

The PDF includes a summary in English.

  • Pohjois-Suomen uitto-olojen järjestelykomitea, ORCID ID:E-mail:
article id 4640, category Article
Jaakko Jalas. (1953). Rokua : suunnitellun kansallispuiston kasvillisuus ja kasvisto. Silva Fennica no. 81 article id 4640. https://doi.org/10.14214/sf.a9102
English title: Vegetation and flora in the planned national park of Rokua in Northern Finland.

The 4.4 km2 sized area of Rokua is a sandy ridge situated in the transitional zone between Central and Northern Finland. It has been suggested to become a new national park due to its, in the area unique landscape and geological characteristics.

The vegetation of the area has been little studied. A vegetation analysis was performed in 1945, 1947 and 1949. Due to low nutrients in the sandy soil, the number of species is relatively low, including 236 vascular plants. The climate is continental. Lichen covering of soil in the Scots pine (Pinus sylvestris L.) dominated forests is mostly intact compared to the more northern areas, because grazing of reindeer has been little. Fellings have increased in the surrounding areas of the planned national park. The article includes a detailed description of vegetation and flora in the area.

The article includes a summary in German.

  • Jalas, ORCID ID:E-mail:
article id 4597, category Article
Lauri Teivainen. (1949). Pisavaaran luonnonpuiston metsäkasvillisuudesta ja kasvistosta. Silva Fennica no. 65 article id 4597. https://doi.org/10.14214/sf.a13978
English title: Forest vegetation and flora of Pisavaara national park.

A vegetation survey was conducted in the Pisavaara national park in Northern Finland in 1946 and 1947. The national park (49,9 km2) includes southern half of the Pisavaara hills. The rock is quartzite. The most common vegetation type is dry upland forest type, but also fresh mineral soil sites are typical for the area.

The most common forest type, Empetrum-Myrtillus type coveres almost as much of the area as all the other forest types combined. The article describes in detail the vegetation of all forest types and gives a complete list of all plant species found in the survey. Total of 291 vascular plants was found, 242 of which were native to the area. In addition, 49 anthropochores had spread to the area when the forest ranger’s cottage was built. Number of species growing in the northern edge of their natural range is. Southern species can be found in the southern slopes of the hill.

The article includes an abstract in German.

  • Teivainen, ORCID ID:E-mail:
article id 4522, category Article
A. V. Auer. (1937). Muhkurin kasvisto. Silva Fennica no. 41 article id 4522. https://doi.org/10.14214/sf.a9067
English title: Vegetation in Muhkuri experimental area in southwest Finland.

A vegetation analysis was performed in Muhkuri experimental area of the Forest Research Institute. The area is located in southwest Finland near city of Turku. The dominant tree species of the area is oak (Quercus robur L.) which can be found in all the area. Common woody species are also aspen (Populus tremula L.), mountain ash (Sorbus aucuparia L.), hazel (Corylus avellana L.), juniper (Juniperus communis L.) and mountain currant (Ribes alpinum L.). A total of 198 vascular plants were found in the area, 34 of which were common in most parts of the area. Typical vegetation of different parts of the area is described. Finally, a list of all plant species is presented in the article.

The PDF includes a summary in German.

  • Auer, ORCID ID:E-mail:
article id 4464, category Article
Esko Kangas. (1932). Tutkimuksia kaasutuhoista Imatran valtionpuistossa. Silva Fennica no. 23 article id 4464. https://doi.org/10.14214/sf.a9020
English title: Studies on gas damages in the state forests in Imatra.

A forest damage was detected in spring 1931 near electro-chemical factory in Imatra in Eastern Finland. It was deduced that it was caused by a gas discharge from the factory. A survey was made to describe the damages. Forests in the damaged area of five hectares were Scots pine (Pinus sylvestris L.) dominated and 60-80 years old. According to the factory, the exhaust gases contained 0.4 mg chlorine per liter. In addition, chlorate containing liquids evaporated thorough the chimney, which seemed to have been the main cause of the damage. The chlorates may have concentrated in the snow covering the trees during the winter. The Scots pine trees had lost all the needles in spring, but grew new needles in the summer. In some trees the new needles were few or undeveloped. Some mild damages were noticed in pine and Betula sp. during the growing season. Forest edges and trees higher that the other trees were worst damaged. Pine was most sensitive to the emission. Pine weakened by the gas damages were attacked by insects, the most important being Pissodes sp. The secondary insect damage is likely to kill the surviving trees. The dying pines should be removed only if it is necessary to prevent the spreading of insect damage. The trees may hinder the spreading of further gas emissions. In future, other tree species should be preferred over pine.

The PDF includes a summary in German.

  • Kangas, ORCID ID:E-mail:

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