Suo - Mires and peat 41 (1990)
Motor-manual treatment of young stands on peatlands.
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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
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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
Näytelieriön täyttötavan vaikutus kasvuturpeen vedenpidätyskykyyn.
English title: The effect of sample handling on the water retention of growth peat substrate.
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The water retention of Sphagnum peat substrate as used in the production of containerized forest tree seedlings was determined at increasing matric potentials from saturation. Samples of commercially available peat substrate were taken and compressed to correspond to a wet bulk density of 0.2 g cm-3 — the value of the substrate used in practice in the nursery. The samples were saturated (-0.1 kPa) and the water content determined after applying successive matric potentials of -1, -10 and -100 kPa by means of a pressure plate apparatus. The effect of loosening the substrate was investigated, as was also the effect of applying the higher potentials directly to saturated samples. The volumetric water retention varied between 88-93% at -0.1 kPa, 72-85% at -1 kPa, 29-30% at -10 kPa and 18-25% at -100 kPa. Loosening the substrate between applying successively higher potentials to the same samples and, in the case of the higher potentials, determining retention directly from saturated samples gave the lower retention values. It was concluded that the most natural and practical way to determine water retention is to use the same samples, successively applying higher potentials without loosening between applications. Such a procedure includes the effect of increasing compaction and changes in pore size distribution of the substrate upon drying.
Keywords: Compaction, matric potential, shrinkage, water content
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Heiskanen,
The Finnish Forest Research Institute, Suonenjoki Research Station, SF-77600 Suonenjoki, Finland
Sähköposti:
ei.tietoa@nn.oo
Maan happiolot soistuvissa havumetsissä.
English title: Soil oxygen conditions in paludifying boreal forest sites.
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Soil oxygen conditions were characterized with the help of polycarbonate tubes, which were filled with water and inserted into the soil. The oxygen content of the water inside the tube was measured and compared with that in conditions of full aeration. Five forest sites were studied. Three of them form a moisture gradient — mesophyte spruce forest (MSF), paludifying spruce forest (PSF) and paludified pine forest (PPF). For comparison, three other sites were included: a dry pine forest (DPF), an alder carr mire (ACR) and an ombrotrophic bog. Soil aeration conditions were the most unfavourable at the PSF site at the beginning of June; the lowest values being recorded in depressions with Sphagnum girgensohnii. Considering the whole vegetation period, the bog site demonstrated the lowest soil aeration level. At the alder carr site, soil aeration conditions were dependent on precipitation. In forest sites the lowest aeration level was observed at the beginning of June, but in the ACR and bog sites, another minimum occurred in September after heavy rains.
Keywords: Coniferous forest, oxygen conditions, paludification, succession
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Zobel,
Department of Botany and Ecology, Tartu University, Lai St. 40, Tartu 202400, Estonia
Sähköposti:
ei.tietoa@nn.oo
The Finno-Swedish mire terminology.
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The Swedish botanical mire terminology used in Finland for teaching students in biology at the University of Helsinki/Helsingfors and pupils in primary and secondary schools differs from that used in silviculture, e.g. by forestry technicians. In this paper some discrepancies between the mire terminologies used by the Swedish-speaking people in Finland, as well as the Swedish mire terminology used in Sweden are elucidated. An improved Swedish terminology is suggested.
Key words: Classification, peatland, terminology
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Haeggström,
Department of Botany, University of Helsingfors, Unionsgatan 44, SF-00170 Helsingfors, Finland
Sähköposti:
ei.tietoa@nn.oo
Esimerkki pseudolajien runsauskynnysten muuntelun vaikutuksesta TWINSPAN-Iuokittelussa.
English title: The effect of pseudospecies cut level settings on the results of TWINSPAN classification.
Avainsanat:
drained peatlands;
mire classification;
vegetation;
mire site type;
multivariate analysis
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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
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Hotanen,
The Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, SF-80101 Joensuu, Finland
Sähköposti:
ei.tietoa@nn.oo
Tuhka-ajoitusmenetelmän ja sammalvuosikasvainajoituksen vertailu rahkamättäissä.
English title: A comparison of ash dating and moss-increment dating in Sphagnum hummocks.
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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
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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
Turvesaannon arviointi suotyypin ja turpeen syvyyden perusteella.
English title: Estimation of peat yield of different peat deposit types.
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Preliminary regression models are produced for the estimation of dry peat yield (tons) per unit area (hectare) for different types of peat deposits with different peat thickness. The models are based on 6 500 peat samples obtained for bulk density measurements from 245 vertical peat profiles (70 virgin and drained peadands) in Finland. In general, the increase in the peat yield does not take place in 1:1 relationship with depth because average bulk density tends to decrease with peat deposit thickness. Fairly reliable estimates of the peat yield using depth and mire site type were obtained. R2 values for the eight models representing eight different groups of "mire site types" ranged from 86.0 to 95.3%.
Keywords: Bulk density, mire site types, peat deposits, peat resources
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Tolonen,
Department of Biology, University ofJoensuu, P.O. Box 111,SF-80101 Joensuu, Finland
Sähköposti:
ei.tietoa@nn.oo
- Ijäs, Sähköposti: ei.tietoa@nn.oo
Suoekosysteemin toiminnallinen ryhmitys.
English title: The functional grouping of mire ecosystems and their response to drainage.
Avainsanat:
mire classification;
mire site types
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The results of inventories of drained peatlands have occasioned criticism of profitless drainage. For the better understanding of the mire ecosystem a functional and structural division of mires is presented. This is based on the nutrient cycle, the mire margin — mire expanse-effect, the carbon balance and the community structure of mire sites. The suitability for drainage is discussed on the basis of the ecology. A suggestion is made for further treatment of drained mire complexes.
Keywords: Mire classification, mire site types
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Eurola,
Department of Botany, Oulu University, SF-90570 Oulu, Finland
Sähköposti:
ei.tietoa@nn.oo
- Huttunen, Sähköposti: ei.tietoa@nn.oo
Skotlannin peittosuot ja niiden suojelu.
English title: Scottish blanket mires and their conservation.
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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
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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
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