Artikkelit jotka sisältää sanan 'peatlands'

Metsäkeskusten kunnostusojitushankkeiden metsikkökuvioista muodostettiin satunnaisesti yhdistäen kolme 35–50 hehtaarin suunnittelualuetta, joiden avulla tarkasteltiin ns. kerralla kuntoon -menettelyn mukaisten (toteutetaan kunnostusojituksen lisäksi kaikki tarpeelliset metsänhoitotoimet yhdellä kerralla koko suoalueelle) ja toisaalta metsänhoitosuosituksia kuvioittain mukailevien metsänkäsittelyjen tuotos- ja talousvaikutuksia. Pääasiassa karuhkoja rämeitä edustavien alueiden puustojen kehitykset simuloitiin kunnostusojituksen ajankohdasta päätehakkuuseen saakka. Erityishuomiota kiinnitettiin alueisiin sisältyvien vähäpuustoisten kuvioiden ensiharvennusten voimakkuuteen sekä harvennusten ajoittumiseen suhteessa kunnostusojitukseen. Harvennusten myöhentäminen sekä vähäpuustoisilla että muilla ns. normaalipuustoisilla kuvioilla paransi koko suunnittelualueen pitkän aikavälin taloustulosta jonkin verran, mutta vähäpuustoisten kuvioiden käsittelyajankohdan vaikutus oli selvästi suurempi. Harvennuksia myöhentämällä myös ensiharvennusten ainespuukertymä kasvoi. Jos vähäpuustoiset kuviot kuitenkin harvennettiin kunnostusojitusvaiheessa ja samaan aikaan normaalipuustoisten kuvioiden kanssa, paras tulos saavutettiin suhteellisen voimakkailla harvennuksilla. Vähäpuustoisten kuvioiden jättäminen kokonaan harventamatta johti heikoimpaan aluetason taloustulokseen. Metsänkasvatuksen pidemmän aikavälin kannattavuutta voitaisiin käytännössä parantaa rajaamalla kunnostusojitusalueen vähäpuustoiset kuviot omiksi käsittelylohkoikseen ja siirtämällä niiden harvennukset toteutettaviksi vasta alueen seuraavalla hakkuukierrolla.

• Kojola, Soili Kojola, Metsäntutkimuslaitos, Etelä-Suomen alueyksikkö, PL 18, 01301 Vantaa, Puh./Tel. 029 532 2111, Fax: 029-532 2103, email: soili.kojola@metla.fi Sähköposti: ei.tietoa@nn.oo
• Penttilä, Sähköposti: ei.tietoa@nn.oo

In the next few decades, industrial peat extraction will cease gradually over more than 80,000 hectares of cutaway peatlands in Ireland and alternative land uses will change the landscape of these areas. This study showed that substantial natural regeneration of downy birch (Betula pubescens) can occur on abandoned as well as cutaway peatlands afforested with conifers. Natural seedling birch stands measured in this study had an estimated biomass production of between 3100 and 5800 kg dry matter ha–1 year–1. This corresponded to an annual carbon stock increment estimated at between 1500 and 2900 kg C ha–1. Direct sowing experiments conducted in this study were the first of their kind in Ireland and showed that sowing downy birch and fertilization with P and K could be a possible management option for the after-use of cutaway peatlands. Exposure was the main obstacle to successful germination and artificial shelter led to higher rates of germination and survival of birch seedlings after the first winter. It can be concluded that birch (naturally or artificially established) can be a feature of this future landscape, bringing many attributes: nurse species, biomass, increased woodland cover and biodiversity.

• Renou-Wilson, F. Renou-Wilson, School of Biology and Environmental Science, Agriculture and Food Centre, University College Dublin, Belfield, Dublin 4. Tel: +353 17167725; Fax: +353 17161102; email: Florence.Renou@ucd.ie Sähköposti: ei.tietoa@nn.oo
• Pöllänen, Sähköposti: ei.tietoa@nn.oo
• Byrne, Sähköposti: ei.tietoa@nn.oo
• Wilson, Sähköposti: ei.tietoa@nn.oo
• Farrell, Sähköposti: ei.tietoa@nn.oo

Riekkokannat Suomen eteläisissä osissa ovat heikentyneet merkittävästi viime vuosikymmenten aikana. Yhtenä keskeisenä tekijänä tälle on esitetty predaation ja metsästyspaineen ohella varsinkin avosoiden kuivattamista ja metsittymistä, jotka ovat muuttaneet riekkojen elinympäristöjä. Yhtenä syynä riekon vähenemiselle voi olla ravinnon määrän, laadun ja saatavuuden pieneneminen. Suurin osa aiemmista riekkojen ravinnonkäytön ja -valinnan tutkimuksista on tehty Lapissa kupujen sisältöjen perusteella, mutta tietoa eteläisen Suomen riekkojen ravintokäyttäytymisestä on hyvin vähän. Tässä tutkimuksessa tutkittiin riekkojen talviravinnon käyttöä ja valintaa Itä-Suomessa Ilomantsissa ja Joensuun Uimaharjussa. Näillä alueilla elää vielä pieniä riekkopopulaatioita. Tutkimuksessa selvitettiin riekkojen kokonaisravinnonkäyttöä syönnösjälkiä laskemalla. Riekkojen suhteellista ravinnonkäyttöä selvitettiin laskemalla lumijälkiä eri kasvilajien tuntumasta sekä kartoittamalla kasvillisuutta kahdessa eri mittakaavassa. Valintakokeessa riekoille tarjottiin kuutta eri pajulajia sekä hieskoivua. Riekkojen käyttämä ravinto koostui kiiltopajusta (Salix phylicifolia), pohjanpajusta (S. lapponum) ja tuhkapajusta (S. cinerea). Mustuvapajua (S. myrsinifolia) riekot söivät mielellään silloin, kun sitä oli tarjolla. Hieskoivua (Betula pubescens) riekot käyttivät ravintonaan vain vähän. Suhteessa tarjolla olevan ravinnon määrään vaivaiskoivu (Betula nana), mustuvapaju, halava (S. pentandra) ja pohjanpaju olivat halutumpia kuin kiiltopaju, mutta kiiltopaju saattaa kasvutapansa vuoksi tarjota riekoille helpommin saatavaa ravintoa. Valintakokeen mukaan riekot ovat pajulajien suhteen generalisteja. Valintakokeessa olivat mukana pohjanpaju, tuhkapaju, kiiltopaju, mustuvapaju, halava, virpapaju (S. aurita) ja hieskoivu. Virpapajua ja hieskoivua syötiin vähemmän kuin muita mukana olleita kasvilajeja. Valintakokeessa vuosikasvujen kärjet olivat suositumpaa ravintoa kuin silmut. Riekkoja olisi mahdollista ruokkia talven yli, sillä ne oppivat testilajien paikat ja palasivat samoille paikoille syömään uudet testiasetelmat. Riekot tarvitsevat vuoden aikana useita erilaisia elinympäristöjä, jotka ovat riittävän lähellä toisiaan. Eteläiset riekkopopulaatiot tarvitsevat selviytyäkseen sekä avosoita, kangasmetsiä että pajua tarjoavia talvielinympäristöjä. Tulosten perusteella talviravintoa esiintyi tutkimusalueilla riittävästi, eivätkä ravinnon määrä, laatu tai saatavuus rajoittanut riekkojen elinmahdollisuuksia.

• Miettunen, Jenni Miettunen, Itä-Suomen yliopisto, Luonnontieteiden ja metsätieteiden tiedekunta, biologian laitos, PL 111, 80101 Joensuu, email: jenni.miettunen@gmail.com Sähköposti: ei.tietoa@nn.oo

With the cessation of industrial peat harvesting, there is an opportunity to create new landscapes that can confer both socio-economic and ecological benefits. This paper reviews over 50 years of study in the after-use potential of industrial cutaway peatlands in Ireland. The options for after-use are determined to a large extent by the residual peat type, hydrological constraints, geographic location and economic considerations. Over the years, the main areas of investigation have included commercially driven options such as agriculture, forestry, and biomass production, as well as the more ecological and environmental options such as dryland recolonisation and wetland creation/restoration. In that time, the emphasis has continually changed as new research has emerged, in turn directing and shaping decision-making. By 2050, around 80000 ha of harvested peatlands will have become available for other uses. As such, a coherent post-harvesting strategy, underpinned by previous and future research, is essential in order to maximise the potential of these new ecosystems.

• Renou, School of Biology and Environmental Science, Agriculture and Food Science Centre, University College Dubline, Belfield, Dublin 4, Ireland Sähköposti: ei.tietoa@nn.oo
• Egan, Sähköposti: ei.tietoa@nn.oo
• Wilson, Sähköposti: ei.tietoa@nn.oo

The effects of potassium (K) fertilisation on the nutrient status and growth of Scots pine (Pinus sylvestris L.) stands on drained peatlands were studied on three field experiments in northern central Finland. The Scots pine stands were at a sapling or pole stage with a dominant height of 3–8 m when the experiments were set up. The stands differed from each other in their nutritional status, for example, the foliar K concentration varied considerably between the experiments. The experiments were fertilised with potassium chloride, rock phosphate (P 42kg ha-1) and urea (N 46kg ha-1) between 1979 and 1980. The potassium doses in terms of elemental K, were 50, 100, 200 and 400kg ha-1. The foliar samples were taken three times during the study period: 7–9 years, 14–15 years and 19–20 years after fertilisation. The stand measurements were done 19–22 years after the fertilisation. The rate and magnitude of stand response due to fertilisation depended essentially on the nutritional status of the trees. The strongest effect of PK-fertilisation was obtained on a nitrogen-rich peatland, where the stands suffered from severe phosphorus and potassium deficiencies (foliar P concentration < 1.2 mg g-1, K concentration < 3.5 mg g-1). During the study period, the annual stand volume growth on fertilised plots ranged from 3.9 to 5.4 m3 ha-1 a-1, and that of the unfertilised plots was 0.78 m3 ha-1 a-1. In other sites, where the lack of phosphorus and potassium was not so drastic, nor did the trees suffer from shortage of nitrogen, the effect of PK-treatment on tree growth was weak or almost non-existent. The foliar K concentrations rose with the amount of potassium chloride applied. The fertilisation effect of the dose of 100kg K ha-1 lasted 15–20 years, after which the foliar K concentration dropped close to the deficiency limit. The effect of the larger doses (200–400kg K ha-1) on the needle K concentration was more pronounced and still visible at the end of the study period. However, the stand growth responses gained with larger potassium applications were not essentially greater than those with the 100 kg ha-1 dose.

• Pietiläinen, Finnish Forest Research Institute, Muhos Research Station, Kirkkosaarentie 7, FIN-91500 Muhos, Finland Sähköposti: ei.tietoa@nn.oo
• Moilanen, Sähköposti: ei.tietoa@nn.oo
• Vesala, Sähköposti: ei.tietoa@nn.oo

In Finland, the whole peat layer of a peat production area is used due to the value of the basal peat as energy peat. In this situation the properties of the mineral subsoil below the peat layer are significant when choosing the form of after-use. The geochemical provinces are based on the chemical features of the fine material in till, related to differences found in the bedrock, defined by Geological Survey of Finland. The study of peat production areas (1998-1999, covering 9800 ha) shows that the characteristics of the provinces affects the subsoil sediments. In Lake Ladoga–Bothnian Bay zone subsoils were rich in sulphur and iron. The amount of water soluble sulphur was 3-6 times higher than that in the Granitoid area of Central Finland and the Archaean gneiss areas (calculated as mg kg-1). Below the highest shoreline of the ancient Litorina Sea the average content of the water soluble sulphur in subsoil sediments was ca. seven fold compared to the content found above the highest shoreline, (calculated as mg kg-1). There was also a difference in soil acidity between these areas. Nutrient content varied between sediments, which have the same fine material percentage. In the Lake Ladoga–Bothnian Bay geological zone and in the zones of Svecocarelian schists and gneisses, natural nutrient levels are high when compared to the Granitoid areas.

• Picken, Kekkilä Oyj, P.O. Box 67, 04300 Tuusula, Finland Sähköposti: ei.tietoa@nn.oo

The development, structure, production and fertilisation of planted black spruce (Picea mariana (Mill.) B.S.P) and Scots pine (Pinus sylvestris L.) stands growing on a drained, originally treeless Sphagnum papillosum fen (LkKaN) in Central Finland up to the age of 30 years were studied. For black spruce the stem number was 2250 stems ha–1, dominant height was ca 7.1 m, the mean stand volume 26 m3 ha–1, the annual mean volume increment 1.5 m3 ha–1 and the total mortality based on stem number was 21%. For Scots pine the comparable characteristics were 1015 stems ha–1, 10.4 m, 45 m3 ha-1 , 3.3 m3 ha-1 and 59% respectively. Fertilisation had no apparent impact on the stand characteristics. About 63% of the planted black spruce individuals had at least one vegetatively generated layer. High number of layers seemed to have a negative effect on dominant parent tree growth. It is concluded that growth and yield of black spruce are generally not competitive in operational forestry in Finland. However, black spruce could be used as an alternative tree species in treeless areas that resist afforestation, and it might also be cultivated for decorative purposes.

• Sarkkola, Department of Forest Ecology, P. O. Box 27, Fin-00014 University of Helsinki Sähköposti: ei.tietoa@nn.oo
• Päivänen, Sähköposti: ei.tietoa@nn.oo

The effects of refertilisation and growing density on the soil and tree nutrition, root penetration and growth of Scots pine stands were studied in a cutaway peatland area with deep peat layers. The fertilisation treatments were control, N1975+PKB1985 and PK1975+PKB1996 refertilisations and those of the growing density <1 300, 1 654 and 1 954 trees ha-1. The maximum root penetration varied between 26 and 34 cm independently of the treatments. The N/P ratios in pine needles were quite high even on the refertilised plots (11.6-15.7). The duration of P fertilisation seems to be shorter (about 15 years) on cutaway peatlands with deep peat layers than on drained peatland forests. The greatest yield without natural removal (239 m3 ha-1, on an average) in 35-years-old stands was measured on plots, which had the highest growing density and had been repeatedly fertilised with PK. The results show that quite a high yield of Scots pine can be reached on cutaway peatlands. However, pine has to be fertilised with PK at the afforestation stage and at least once later if the remaining peat layer is 40-60 cm, and possibly several broadcast fertilisations are needed on peat layers deeper than 60 cm. It seems that growing tree stands on cutaway peatlands in higher densities than in conventional forestry may improve nutrient cycling in stands and hence decrease leaching of nutrients from the site.

• Aro, Finnish Forest Research Institute, Parkano Research Station, Kaironiementie 54, FIN-39700 Parkano Sähköposti: ei.tietoa@nn.oo
• Kaunisto, Sähköposti: ei.tietoa@nn.oo

Nitrous oxide (N2O) fluxes were measured on ten natural minerotrophic peatlands in an area planned for a hydroelectric reservoir (Vuotos) in northern Finland. The mean N2O fluxes from the sites with mean water tables from –25 to 3.4 cm (negative below the peat surface) ranged from –30 to 230 µg m–2 d–1 during summer 1994. At the driest site, the herb-grass spruce mire with the mean water table at –38 cm, the mean summertime N2O emission was 940 µg m-2 d-1 in 1994, attributable to the increased N2O release at low peat temperatures in autumn. A similar increase in the N2O emissions was not found in 1995, as the measurements were finished before the peat started to freeze. The mean N2O fluxes at the sites correlated negatively with the mean water table levels. The peatlands in the northern boreal zone are unlikely important sources of atmospheric N2O in their natural state. The planned reservoir would barely have large long-term N2O emissions from the pelagic zone, but the importance of temporally flooded areas in the postflood N2O release is uncertain similar to the short-term emissions following the flooding.

• Huttunen, Research and Development Unit of Environmental Health, Department of Environmental Sciences, Bioteknia 2, University of Kuopio, PO Box 1627, FIN-70211 Kuopio, Finland Sähköposti: ei.tietoa@nn.oo
• Nykänen, Sähköposti: ei.tietoa@nn.oo
• Turunen, Sähköposti: ei.tietoa@nn.oo
• Nenonen, Sähköposti: ei.tietoa@nn.oo
• Martikainen, Sähköposti: ei.tietoa@nn.oo

The study deals with the natural regeneration of Scots pine (Pinus sylvestris) and birch (Betula pendula & B. pubescens) on ten experimental fields on peatland sites drained for forestry, mainly during the 1930s. The principal goal of the study was to investigate the effect of different types of natural ground vegetation on the restocking of pine and birch following site preparation (rotavation and mounding) on old drainage areas. Rotavation, which corresponds to disc trenching on upland forest soils, is capable of producing fully-stocked pine stands. The effect of surface treatments such as rotavation depends, however, on the predominant ground vegetation. Sphagnum moss patches are often well restocked even when not prepared, which means that site preparation often only has an effect on transformed Pleurozium and Dicranum vegetation. The success of rotavation has also encouraged forest owners to use other alternative methods of surface treatment such as mounding. The tree seedlings tend to be concentrated on the surface of the furrows produced by rotavation, which means that restricting digger-scarification to the topmost surface of the soil on well-drained regeneration sites can produce the same result; the required machinery is usually already present at the site for ditch network maintenance.

• Saarinen, The Finnish Forest Research Institute, Parkano Research Station, Kaironiementie 54, 39700 Parkano, Finland Sähköposti: ei.tietoa@nn.oo

A mechanistic simulation model of organic matter accumulation for a developing fen/ raised bog complex in Ireland is presented.Parameter/variable values have been prima rily drawn from the published literature.The development of the theoretical considera tions of fen peat as a substratum to a raised bog is evaluated using the model.Terrestri alization is the pathway of hydroseral succession.The conceptual model treats peat growth as the accumulation of a series of parcels comprising both a labile and a non- labile component.The fen phase of the model uses a discrete description of organic matter accumulation while the raised bog phase uses a continuous description.Both phases use a constant decay rate.The model integrates changes in net primary produc tivity and aerobic decay to simulate four climatic periods.The model generates outputs for peat depth and mass with time and profiles of bulk density with depth.Results over a simulated period of 10 000 years demonstrate how changes in surface net primary productivity and aerobic decay can change the rate of peat accumulation in the develop ing fen/raised bog complex.Sensitivity analysis showed that the most important pa rameters influencing simulated depth and mass were the labile fraction in organic mat ter (raised bog)followed by net primary productivity (raised bog).The potential sig nificance of underlying fen peat as a proportion of the total depth and mass of a devel oping fen/raised bog complex was evaluated and shown to be substantially diminished after 5 000 years.It was established that the model predictions corresponded well with data for Irish Midland bogs and given suitable adjustment of values, could potentially simulate Fennoscandian conditions as well.

• Gilmer, Department of Agricultural & Food Engineering (Peat Technology Centre), University College Dublin, Earlsfort Terrace, Dublin 2, Ireland Sähköposti: ei.tietoa@nn.oo
• Holden, Sähköposti: ei.tietoa@nn.oo
• Ward, Sähköposti: ei.tietoa@nn.oo
• Brereton, Sähköposti: ei.tietoa@nn.oo
• Farrell, Sähköposti: ei.tietoa@nn.oo

Peat hydraulic conductivity, shear strength, plant composition and runoff at seven peat harvesting sites in Central Finland were measured. A large variation in hydraulic conductivity (10–8–10–6 m s–1 ), peat shear strength (302–413 kPa), and peak runoff (97–898 l s–1 km–2 ) was observed between different harvesting sites. The hydraulic conductivity showed a clear correlation with peat shear strength (r = –0.89), which has not been previously observed. The correlation between hydraulic conductivity and degree of humification was weak (r = 0.60). Soil lowering decreased the hydraulic conductivity and the peat shear strength. These reductions, with reduced drainage depths, increased peak flow and changed runoff generation patterns by increasing the possibility of Horton and saturation excess overland flow.

• Kløve, Jordforsk, Norwegian Centre for Soil and Environmental Research, 1432 Ås, Norway Sähköposti: ei.tietoa@nn.oo

Black spruce (Picea mariana, (Mill.) B.S.P.) has been traditionally managed as evenaged stands with artificial or natural regeneration on peatlands of northern Ontario Clay Belt region. However, lack of resources to make artificial regeneration on all clear-cuts and harvest methods unfavorable for natural regeneration often resulted in unsatisfactory regeneration. As a consequence, alternative management methods have been introduced for peatland black spruce, and this literature review discusses studies of these methods. In natural stands, both evenaged and uneven-aged structures may be found, while the second-growth stands originating from old horse-logging are mostly uneven-aged, with abundant advance growth. Currently, mechanized harvest with regeneration protection has been shown to sufficiently preserve residual trees and subsequently produce stands that are heterogeneous with respect to the size structure. In second-growth stands, uneven-aged management can be implemented with minimum diameter limits determined from stand structure and cut-to-length harvesting. Such management perpetuates a stand structure appropriate for uneven-aged management. Simulation study has been made to estimate black spruce yield under uneven-aged management with varying cutting cycle and minimum diameter limit. It seems that in some peatland sites uneven-aged management is a possibility to manage black spruce.

• Hökkä, The Finnish Forest Research Institute, Rovaniemi Research station, P.O. Box 16, FIN-96301 Rovaniemi, Finland Sähköposti: ei.tietoa@nn.oo
• Groot, Sähköposti: ei.tietoa@nn.oo

Drainage of pristine mires has been discontinued in Finland and now drainage activity focuses on remedial treatment of old ditch networks on transformed drained mires. In the era of first-time drainage, uniform regulations were applied in the dimensioning of ditches. Also the current national recommendations pertaining to remedial drainage and the dimensioning of ditches corresponds to the old regulations applied in first-time drainage. However, regional organizations have their own directives, and accordingly ditch depths show considerable regional variation. The purpose of this paper is to look for answers to questions which have arisen already some years ago, especially among practitioners responsible for forest-improvement works in non-industrial, private woodlots: Can the service life of ditch networks be increased by means of ditches which are deeper than those implemented at the time of first-time drainage and will this also result in a reduced impact on water ecosystems by reducing the number of remedial actions needed ? Is ditch depth in old, well-stocked drainage areas a more important factor than ditch spacing in controlling the drainage depth?

• Saarinen, The Finnish Forest Research Institute, Parkano Research Station, Kaironiementie 54, FIN-39700 Parkano, Finland Sähköposti: ei.tietoa@nn.oo
• Silver, Sähköposti: ei.tietoa@nn.oo
• Joensuu, Sähköposti: ei.tietoa@nn.oo

Various types of peatlands are present in Wallony: raised bogs, oligotrophic and rich fens, wet heaths, marshy woodlands. Many areas have been degraded by past and recent human activities. Much attention is now devoted to their protection, scientific study and ecological management. Besides their exceptional biological and ecological interest, they are among the last natural spaces in a very urbanised country like Belgium.

• Frankard, Centre scientifique de la Région Wallonne, c/o Station scientifique des Hautes-Fagnes, rue de Botrange, 137, B-4950 Robertville, Belgium Sähköposti: ei.tietoa@nn.oo
• Ghiette, Sähköposti: ei.tietoa@nn.oo
• Hindryckx, Sähköposti: ei.tietoa@nn.oo
• Schumacker, Sähköposti: ei.tietoa@nn.oo
• Wastiaux, Sähköposti: ei.tietoa@nn.oo

The rate of renewal of forests on drained peatlands in Finland will undergo a rapid rise in the near future as a large amount of these forests is approaching their renewal age. Indeed, forest renewal increasingly calls for familiarity with the special characteristics of peatland habitats. These special characteristics making them different from upland sites are primarily connected to hydrology, temperature conditions, nutrient status, and to changes in the composition of the ground vegetation. This literature review is focused on the effects of these site factors on the germination of tree seeds and the initial development of seedlings on different seedbeds. Key words: drainage areas, natural regeneration, peatlands

• Saarinen, Finnish Forest Research Institute, Parkano Research Station, Kaironiementie 54, FIN-39700 Parkano, Finland Sähköposti: ei.tietoa@nn.oo

Abstract: The foliar chemical composition of a Norway spruce underwood were analysed one year before and in three years after the removal of a downy birch (Betula pubescens Ehrh.) shelterwood on an old drainage area. The most remarkable change due to the release was considered to be the significant decrease in the potassium concentrations. The nitrogen concentrations increased very strongly, and phosphorus increased slightly but not significantly during the first growth period after the release, decreasing later to a level approaching the deficiency limit. Consequently the nutrient balance between N and K was strongly shaken by the increased N/K-ratio. One reason for that might be the increased use of K in the growing points of roots after the root competition of shelterwood was eliminated. Key words: foliar analysis, nutrients, peatlands, Picea abies, shelterwood, underwood.

• Saarinen, The Finnish Forest Research Institute, Parkano Research Station, Kaironiementie 54, FIN-39700 Parkano, Finland Sähköposti: ei.tietoa@nn.oo

Today the emphasis in forest drainage in Finland is on the maintenance of old ditch networks. In connection with these maintaining activities all silvicultural cuttings should also be carried out, because on most old drained peatlands, thinnings are often badly neglected. The aim of this investigation was to determine the need and present extent of silvicultural cuttings in the area of the Satakunta forestry board, in southwest Finland. The main results were that only half the necessary cuttings had been carried out in connection with ditch maintenance. Keywords: Peatlands, cuttings, ditch cleaning

• Silver, Satakunta District Forestry Board, Itsenäisyydenkatu 35 A, FIN-28100 Pori, Finland Sähköposti: ei.tietoa@nn.oo
• Saarinen, Sähköposti: ei.tietoa@nn.oo

An increasing awareness of the environment and the wide extension of mined peatlands require actions and measurements in order to ensure their regeneration and protection. A brief description of the most important peat harvesting methods in North-West Germany shows the stratigraphy of peatlands after exploitation has been finished and ecotechnological actions have been started to initiate a raised bog regeneration. The actions and measurements applied depend also on the properties of the peat as on the properties of the top spit layer. The requirements for a successful rewetting of peatlands will be shown. The terminology concerning the subject of raised bog regeneration will be explained. Keywords: nature protection, peatlands, rehabilitation, top spit

• Roderfeld, Institute of Soil Technology Bremen, Geological Survey of Lower-Saxony, Friedrich-Mifller-Str. 46/50, D-2800 Bremen, Germany Sähköposti: ei.tietoa@nn.oo

The micrometeorological eddy correlation technique was used to measure fluxes of methane and energy. Results from these measurements made in a Minnesota peatland are reviewed here. The field observations made in a pilot study (1990) demonstrated the utility of the eddy correlation technique for measuring surface fluxes of methane. Seasonal distribution of methane flux at the same site was obtained in a detailed study (May to October) in 1991. The evapotranspiration rates and other components of the surface energy budget were also quantified. The daily evapotranspiration during the measurement period (mid May to mid October) ranged from 0.9 to 6.0 mm day-1, with a seasonal average of 3.6mm day-1. Keywords: Eddy correlation technique, methane flux, peatlands

• Verma, Dept. of Agric. Meteorology, University of Nebraska, P.O. Box 830728, Lincoln, NE-68583-0728, U.S.A. Sähköposti: ei.tietoa@nn.oo
• Ullman, Sähköposti: ei.tietoa@nn.oo
• Shurpali, Sähköposti: ei.tietoa@nn.oo
• Clement, Sähköposti: ei.tietoa@nn.oo
• Kim, Sähköposti: ei.tietoa@nn.oo
• Billesbach, Sähköposti: ei.tietoa@nn.oo

In an AMS (accelerator mass spectrometric) determination of 14C from moss-increment dated samples from a Sphagnum fuscum hummock, a clear peak representing the time of high 14C activity in the atmosphere due to nuclear bomb tests was found. The 14C activities in the peat profile at deeper levels, corresponding to the period down to 1600 BP, showed similar variations as the atmospheric values. The time-scale obtained from radiocarbon dating fitted well with results from moss-increment counting, pollen analysis and dendrochronological dating of a fire horizon. Using the bomb activity peak, the fraction of carbon emanating from deeper layers and refixed into growing peat was estimated. The fraction of soil carbon dioxide taken up by the contemporary Sphagnum sward was thus found to be in the order of 20%. Keywords: Moss increment dating, peatlands, radiocarbon, Sphagnum

• Tolonen, Dept. of Biology, Univ. Joensuu, P.O. Box III, FIN-80101 Joensuu, Finland Sähköposti: ei.tietoa@nn.oo
• Possnert, Sähköposti: ei.tietoa@nn.oo
• Jungner, Sähköposti: ei.tietoa@nn.oo
• Sonninen, Sähköposti: ei.tietoa@nn.oo
• Alm, Sähköposti: ei.tietoa@nn.oo

The anaerobic production and potential aerobic oxidation of methane were assessed in a Sphagnum-dominated peatland in Sweden. Peat from four depths in the 0-40 cm (below the vegetation surface) layer was collected in three different plant communities. The rate measurements were made with peat slurries in flasks. The ratio between the mean production and mean oxidation activities was more than ten-fold higher in the two wetter than in the driest community. The within profiles depth distributions of methanogenic and methane-oxidizing activity were similar, showing that a particular level may act as a net source or a net sink for methane, depending on prevailing environmental conditions (primarily the oxygen distribution). The results also suggest that methane production and consumption processes can occur in anaerobic and aerobic micro-zones in very close proximity to each other. Key words: Carbon flow, methane oxidation, methane production, peatlands

• Sundh, Department of Microbiology, Swedish University of Agricultural Sciences, S-750 07 Uppsala, Sweden Sähköposti: ei.tietoa@nn.oo
• Nilsson, Sähköposti: ei.tietoa@nn.oo
• Svensson, Sähköposti: ei.tietoa@nn.oo

Below-ground biomass of dominating vascular plants on a mesotrophic fen and Sphagnum fuscum pine bog was estimated using 14C labelling techniques. Preliminary results show that up to 90% of living biomass of Carex rostrata growing on the fen may be located below ground. Fine roots form the majority of below-ground biomass. Keywords: Peatlands, production, root biomass

• Saarinen, Department of Botany, Laboratories of Ecology, P.O. Box 4, FIN-00014University of Helsinki, Finland Sähköposti: ei.tietoa@nn.oo
• Tolonen, Sähköposti: ei.tietoa@nn.oo
• Vasander, Sähköposti: ei.tietoa@nn.oo

The area of 13 study catchments is 2.5-56.3 km2 and 37-87% of the catchments is covered by peatlands. Ditching intensities varied from 0 to 100%. Median total organic carbon (TOC) in runoff waters from the catchments was 10-30 mg l-1 and median total nitrogen (Ntot) 380-1 000 µg l-1. The annual leaching of TOC and N tot was calculated for five catchments for which daily runoff data was available. The range for mean annual leaching of TOC and Ntot from the catchments was 4 700 to 7 300 kg km-2 a-1 and 190-250 kg km-2 a-1, respectively. The variation between different years was high and annual leaching was closely related to annual runoff. The regional variation in the leaching of TOC and N tot was small compared to the annual variation. Keywords: Hydrology, leaching, organic carbon, peatlands, runoff

• Kortelainen, National Board of Waters and the Environment, Water and Environment Research Institute, P.O. Box 250, FlN-00101 Helsinki, Finland S Sähköposti: ei.tietoa@nn.oo
• Saukkonen, Sähköposti: ei.tietoa@nn.oo

Cushions of Sphagnum fuscum and S. angustifolium were grown in the laboratory in four different C02 concentrations (350, 700, 1 000, and 2 000 ppm) and N deposition levels (0, 10, 30, and 100 kg ha-1 a-1). The same N deposition levels were also applied in the field. C02 concentration increased both the shoot density and dry mass of S. fuscum but decreased the length increment. There was no net effect on production. For S. angustifolium, shoot density did not alter with elevated C02 con-centration but the C02 induced increment in dry mass and length caused increased production. S. angustifolium suffered from nutrient deficiency on the 0 kg N ha-1a-1 treatment and S. fuscum had difficulties to survive at the heaviest N load. No clear trends in length increment or cover was noticed in the field study during the first year. Keywords: Bryophyte ecology, climate change, peatlands, production

• Jauhiainen, University of Joensuu, Department of Biology, P.O. Box 111, FIN-80I0I Joensuu, Finland Sähköposti: ei.tietoa@nn.oo
• Vasander, Sähköposti: ei.tietoa@nn.oo
• Silvola, Sähköposti: ei.tietoa@nn.oo

Fourteen kg ha-1 yr-1 of N enter the mire acrotelm, and 12 are sequestered in the catotelm peat. However, 66 kg ha-1 yr-1 cycle between plant growth and decay in the acrotelm each year, primarily as ammonium and organic N. Fifty eight percent of the sulfate inputs to the mire are retained, but the export of organic sulfur (1.5 kg ha-1 yr-1) yields a total sulfur retention of 37%. As with N, recycling within the acrotelm and vegetation layer is large (12.5 kg ha-1 yr-1). The proton cycle in the mire is dominated by nutrient uptake and plant decay (about 80% of the 1 044 meq m-2 yr-1). Organic acid production is the major source of free acidity (263 meq m-2 yr-1) and buffers the water near pH 4. About half of the metals entering the mire are retained, and about 60% of the P is retained. Retention of P is particularly high (about 80%) during the spring snowmelt season. The carbon cycle at the Marcell mire consists of about 655 g C m-2 yr-1entering and leaving the acrotelm and vegetation. Eighteen to 28 g C m-2 yr-1are sequestered each year in the catotelm (true and apparent rate of accumulation). Net primary production in the moss, tree, and herbaceous layers accounts for about 385 g C m-2 yr-1, while C02 losses in soil and plant respiration account for about 589g C m-2 yr-1. Root net primary productivity (unmeasured) is estimated at 152 g C m-2 yr-1. Water export of C is 37 and methane losses are about 6 g C m-2 yr-1. Keywords: Carbon cycling, global change, Minnesota, nutrient budgets, peatlands

• Verry, USD A- Forest Service, North Central Forest Exp. Stn., 1831 Highway 169 East, Grand Rapids, MN, USA. Sähköposti: ei.tietoa@nn.oo
• Urban, Sähköposti: ei.tietoa@nn.oo

Evidence is presented to show the utility of peatland paleorecords in determining (1) variations in the time of initiation as well as the rate of accumulation of peat and biophilic elements, (2) the history of changes in surface-water acidity and water-table depth, (3) shifts in ground-water influence upon plant communities and the chemistry of the water in which they grow, and (4) alterations in the rate of deposition of diverse pollutants from the atmosphere. This evidence constitutes background information of great value for investigations of the ecological and biogeochemical consequences of global change. Keywords: Geochemistry, global change, hydrology, paleorecord, peatlands

• Gorham, Department of Ecology, Evolution and Behavior, University of Minnesota, 1987 Upper Buford Circle, St. Paul, MN 55108, U.S.A. Sähköposti: ei.tietoa@nn.oo
• Janssens, Sähköposti: ei.tietoa@nn.oo

Japan has approximately 200 000 ha of mires (0.5% of the total land area), and peat reserves of ca. 625 million tons. Because of the great diversity in both climatic and topographic conditions various types of mire and wetlands are found. These range from the large coastal mires in Hokkaido to the mangrove forests with surrounding limnogenic mires in subtropical regions of the Ryukyu Archipelago. The majority of Japanese mires are, however, located in regions of recent volcanic activity and on the alluvial plains of Central Honshu and northwards. Most of the lowland mires have long since been reclaimed for rice culture or have partly been buried under built-up areas. In this paper, different forms of mire utilization are outlined and 30 legally (or otherwise) protected mires in Hokkaido are briefly described. Keywords: Hokkaido, Japan, peatlands, preservation, utilization

• Miyazawa, University of Helsinki, Hyytiälä Forestry Field Station, SF-35500 Korkeakoski, Finland Sähköposti: ei.tietoa@nn.oo

In the southern part of Finland there are over 400 000 hectares of old drainage areas which are on very poor pine mires. This paper presents their problematic site type classification, growing stock variation and some criteria to evaluate the profitability of the ditch network maintenance. Keywords: Classification, drainage, peatlands, profitability

• Saarinen, The Finnish Forest Research Institute, Parkano Research Station, SF-39700 Parkano, Finland Sähköposti: ei.tietoa@nn.oo
• Silver, Sähköposti: ei.tietoa@nn.oo

The variation in groundwater nutrient concentrations from 29 oligotrophy pine mires were described. The relationships between groundwater chemistry and the chemical status of the surface peat layer were also investigated. The mean groundwater quality in different site type fertility groups was: pH 4.0-4.8; NH4+-N 0.45-0.80 mg l-1; P 0.06-0.15 mg l-1; K 0.27-0.54 mg l-1 ; Ca 1.40-3.78 mg l-1; Mg 0.49-1.67 mg l-1; Mn 0.01-0.12 mg I-1; Fe 0.69-3.20 mg l-1; Al 0.34-0.57 mg i-1; Zn 0.006-0.015 mg I-1; Na 0.63-1.91 mg l-1; B 0.008-0.010 mg l-1 and S 1.15-1.47 mg l-1. When ordered from the most infertile to the most fertile site types, groundwater pH and total concentrations of Ca, Mg, Mn, Fe and Na significantly (P < 0.001) increased. There was a large seasonal variation in the concentrations of S, K, Na, B and Zn, and a large within-plot variation in K, NH4+-N, P and B concentrations. The results indicated that factors other than the chemistry of peat were involved in determining the concentrations of these nutrients in the groundwater. Groundwater concentrations of Al, Fe, Ca and Mg, on the other hand, were found to be strongly correlated with the corresponding total nutrient concentrations in the surface peat layer. Keywords: peatlands, peat nutrients, water chemistry

• Nieminen, The Finnish Forest Research Institute, P.O. Box 18, SF-01301 Vantaa, Finland Sähköposti: ei.tietoa@nn.oo
• Pätilä, Sähköposti: ei.tietoa@nn.oo

In connection with an Inter-Nordic research project concerning treatment of young forests, some aspects concerning peatlands were studied. A description of the difficulty of terrain and the importance of nurse crop were reviewed from the point of view of young stand treatment. A field experiment concerning the time needed to keep ditches free from slash was organized. Keywords: Ditches, nurse crop, peatlands, terrain description, young stand treatment

• Kärenlampi, University of Helsinki, Department of Logging and Utilization of Forest Products, Unioninkatu 40 B, SF-00170 Helsinki Sähköposti: ei.tietoa@nn.oo
• Suni, Sähköposti: ei.tietoa@nn.oo

TWINSPAN classifications of the same drained mire vegetation data using four different pseudospecies cut level scales were compared. The material consisted of 96 sample plots located on drained spruce and pine mires in eastern Finland. The pseudospecies cut level scales were the octave scale (0, 0.5, 1, 2, 4, 8, 16, 32 and 64%), a coarse scale (0, 5, 10, 20 and 50%), TWINSPAN default settings (0, 2, 5, 10 and 20%), and presence/absence. The classificatons were quite similar at the first division but they differed markedly from each other at the final third division showing that the choice of cut levels has an important effect on TWIN-SPAN results. The sample plots in one TWINSPAN cluster defined with set of cut levels were allocated to several clusters defined with other cut level settings. The presence/absence setting resulted in a classification which was the most different from the classification made using the default settings. The TWINSPAN classifications performed using the default and octave scale settings corresponded the best with the field classification of the plots and were ecologically the most interpretable. Keywords: Drained peatlands, mire classification, mire site type, multivariate analysis, vegetation

• Hotanen, The Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, SF-80101 Joensuu, Finland Sähköposti: ei.tietoa@nn.oo

A comparison of two methods for dating recent ombrotrophic peat hummocks was made at three mires. For depths approximately below 10 cm, acid insoluble ash dating gave greater ages than moss-increment dating; for depths above 10 cm, the methods showed more similar ages. The moss-increment dates were assumed to be generally correct since there was a good correlation between several independent dating results and moss-increment ages at one of the study sites. Despite the declining accuracy of moss-increment dating with depth, it should be the method chosen for dating recent peat in areas where the assumption of constant acid insoluble ash deposition is invalid. Increment dating is practically useful only in the moss hummocks, except for when the moss stems have been compressed into a horizontal position. Keywords: Dating, mineral dust, peatlands, Sphagnum, surface peats

• Eustis, Department of Ecology and Evolutionary Biology, University of Connecticut, P.O. Box U-42, Storrs, CT 06268, USA Sähköposti: ei.tietoa@nn.oo
• Tolonen, Sähköposti: ei.tietoa@nn.oo

Controversy between the conservation and utilization of Scottish peadands is discussed on the basis of the authors' experience from the excursion of the International Mire Conservation Group (IMCG) to Scotland in September 1986 (EK & PS) and the participation in the international symposium "Peatland Ecosystems and Man: An Impact Assessment" in Dundee, Scotland in September 1989 (HV). Many blanket mires, especially in north-central Scotland, have an international conservation value. At the same time almost one fifth of this mire area has been afforested. The purpose of the Nature Conservancy Council is to conserve as large watershed areas as possible and to guide afforestation to those areas which have already lost their naturalness. There is now an urgent need of mire conservation in Scotland in order to save distinguished areas of Scottish blanket mires. Key words: afforestation, peatlands, preservation, Scodand

• Kaakkinen, Provincial Government in Oulu, P.O. Box 293, SF-90101Oulu, Finland Sähköposti: ei.tietoa@nn.oo
• Salminen, Sähköposti: ei.tietoa@nn.oo
• Vasander, Sähköposti: ei.tietoa@nn.oo

While approximately 10% of agriculture in Finland is still carried out on peat soils, the area involved is decreasing faster than the area of mineral soils. However, the large reserve of peatlands in Finland may become important in the future for agricultural production as a result of global climatic warming which would move the best agricultural areas northwards. Keywords: Agriculture, peat cultivation, peat soil, peatlands

• Heikkilä, Society of Peat Cultivation, Karelia Research Station, SF-82600 Tohmajärvi, Finland Sähköposti: ei.tietoa@nn.oo

The preservation of Finnish mires effectively started in 1965 when the Finnish Association for Nature Protection and the Finnish Peatland Society formed a joint committee for mire protection. This committee, chaired by the author, produced a conservation programme primarily for state-owned lands, comprising altogether 209 protection areas in different vegetation zones of Finland. Consequently, the majority of the areas suggested came under the jurisdiction of the National Board of Forestry. In 1976, a new working group was established by the Ministry of Agriculture and Forestry to assess the scientific basis of peatland protection and to prepare a comprehensive national programme for preserving Finnish mires. Most of the members of the previous committee were able to participate in the activities of the new working group. In 1979 and 1981 the Finnish Government approved in principle the basic protection plans which included approximately 600 mires covering a combined area of 0.5 Mha. In addition, national parks and strict nature reserves contain about 0.2 Mha of mires. The objective is to preserve ca. 7% of the original area (10 Mha) of Finnish peatlands. During the 1980s, some 400 000 ha of mire preservation areas have been established on state-owned land, while about 85 000 ha of privately-owned mires (included in the conservation programme) still remain unprotected. There is a clear need to complete the mire conservation programme, especially in southern Finland. Keywords: Nature conservation, peatlands

• Ruuhijärvi, University of Helsinki, Department of Botany, Ecological Laboratories, Fabianinkatu 24A, SF-00100 Helsinki, Finland Sähköposti: ei.tietoa@nn.oo

Approximately half of the original area of Finnish peatlands, 10 Mha, have been drained for forestry. In addition slightly less than 1 Mha of paludified mineral soil have been drained. The drained area comprises approximately one quarter of the present total forest area in Finland and the current growth of tree stands on drained peatland forests is steeply increasing. Thus the increase in the annual growth increment due to forest amelioration is presently c. 8 Mm3 and increasing by several percent each year. While this trend is welcome a third of drained peatland area already needs urgent additional drainage and silviculture management if it is to continue. Keywords: Drainage, peatlands, silviculture

• Antola, Central Forestry Board Tapio, Maistraatinportti 4A, SF-00241 Helsinki, Finland Sähköposti: ei.tietoa@nn.oo

Up to the present 5 Mha of peatland, i.e. 50% of the total peatland area of Finland, have been drained for forestry. The annual growth of peatland forests has increased from 6 Mm3 in the 1920s up 15 Mm3 in the 1980s, which is 22% of the total annual growth of the country's forests. To maintain the drainage systems, about 40 000 km of ditches should be cleaned annually. Silvicultural management of tree stands on peatlands is another urgent task in the near future. Keywords: Forest drainage, peatlands

• Mikola, Department of Silviculture, University of Helsinki, Unionin-Icatu 40 B, SF-00170 Helsinki, Finland Sähköposti: ei.tietoa@nn.oo

In the Finnish classification of drained peatlands in practical forestry, the post-drainage successional plant communities of recently drained areas have been traditionally classified according to their original mire site type (33 different types in forestry use), whereas the more stable communities of older drainage areas have been classified into so called "drained peat-land forest types" (4 types). This system is not firmly based on ecological factors or forestry requirements. The classification would be more logical and operational in forestry, if the successional plant communities of younger drainage areas already were classified into the drained peatland forest types. The paper describes seven such drained peatland forest types: herb-rich type, Vaccinium myrtillus type (I) and (II), Vaccinium vitis-idaea type (I) and (II), dwarf-shrub type and the Cladina type, which have their parallels in the series of upland forest types. The traditional V. myrtillus and V. vitis-idaea types have each been divided into two types; type (I) develops from genuine, forested mire types and type (II) from treeless and sparsely forested composite types. The proposed classification is supported by tree stand and peat property data presented in the paper. Keywords: Classification, drained peatlands, vegetation

• Laine, Department of Peatland Forestry, University of Helsinki, SF-00170 Helsinki, Finland Sähköposti: ei.tietoa@nn.oo

The author cites examples and discusses the abundant occurrence of mires, peatlands, bogs etc. in the work of two esteemed Finnish poets, Aaro Hellaakoski (1893—1952) and Einari Vuorela (1889—1972). Keywords: peatlands, Finnish literature

• Härkönen, PO.B. 233, 00121 Helsinki, Finland Sähköposti: ei.tietoa@nn.oo

The short-term effects of wood ash, PK and NPK fertilizers on total N and P contents of various mosses at an old drainage area in eastern Finland are studied. Total N contents increased after NPK treatment and total P contents increased after treatments that contained phosphorus (NPK, PK, wood ash). N contents of some mosses also increased after treatments which did not contain any nitrogen (PK and wood ash). On these plots drainage and obviously the fertilizer treatment fastened the decomposition rate of the peat and at the same time the mobilization of the nutrients. On the control plots (no fertilization) the N contents of the mosses did not differ statistically between the years in either of the study sites. The P contents of some mosses decreased on the control plots of the spruce swamp. One reason for this was apparently the level of the ground water, which did not lower so much in the spruce swamp than in the pine mire, and so the mobilization of the nutrients remained smaller. The observed nutrient contents of the peat mosses were much smaller than those of the forest mosses and the nutrient contents were also smaller at pine mire than at spruce swamp. Keywords: bryophytes, fertilization, drained peatlands, nitrogen, phosphorus.

• Jäppinen, University of Joensuu. Department of Biology. P.O. Box 111, SF-80101 Joensuu, Finland Sähköposti: ei.tietoa@nn.oo

The short-terms effects of wood ash and NPK fertilizer on the population of Enchytraeidae worms in a drained spruce swamp and pine bog were studied. Both NPK fertilizer (300 kg/ha) and ash (3000 kg/ha) treatments reduced worm numbers at both sites, but the effects were slight compared to seasonal fluctuations. Temporal fluctuations in worm numbers were relatively smaller at the pine bog than at the spruce swamp. NPK fertilizer temporarily changed the relative vertical distribution while tha ash treatment did not. The effects upon worm biomass and respiration rate were similar as those for worm numbers . Key words: Enchytraeidae, NPK fertilization, ash fertilization, drained peatlands

• Hotanen, The Finnish Forest Research Institute, Joensuu Research Station, Yliopistonkatu 7, SF-80100 Joensuu, Finland Sähköposti: ei.tietoa@nn.oo

• Herranen, Geologian tutkimuskeskus Sähköposti: teuvo.herranen@gtk.fi
• Toivonen, Sähköposti: tapio.toivonen2@gmail.com

• Väliranta, Environmental Change Research Unit (ECRU), Ekosysteemit ja ympäristö tutkimusohjelma; Helsinki Institute of Sustainability Science (HELSUS) Sähköposti: minna.valiranta@helsinki.fi
• Piilo, Environmental Change Research Unit (ECRU), Ekosysteemit ja ympäristö tutkimusohjelma; Helsinki Institute of Sustainability Science (HELSUS) Sähköposti: sanna.piilo@helsinki.fi
• Zhang, Institute for Atmospheric and Earth System Research (INAR), Fysiikan laitos, Helsingin yliopisto Sähköposti: hui.zhang@helsinki.fi