Suo - Mires and peat 46 (1995)
Kasvillisuus ja C02-tase käytöstä vapautuneella turvetuotantoalueella Kihniön Aitonevalla.
English title: Vegetation and CO2 balance in an abandoned harvested peatland in Aitoneva, southern Finland.
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The vegetation and CO2 balance (difference between C02 fixation rate and respiration rate) in an abandoned harvested peatland in Aitoneva, Kihnio (62° 12'N, 23° 18'E) were studied during the summer of 1994. The daytime CO2 fluxes from sample plots representing different kinds of vegetation were measured using two different static chamber techniques. To investigate the compositional variation of vegetation and its relationship with CO2 balance, data on the vegetation of the sample plots was analysed by global non-metric multidimensional scaling (GNMDS). A total number of 20 plant species was observed on the sample plots. The dominant plant species was Eriophorum vaginatum L. The main variation in GNMDS were connected with colonization stage (total cover of vegetation). The C02 fixation rate varied between -56 and 1869 mg m-2 h-1 and the respiration rate varied between 34 and 1168 mg CO2 m-2 h-1. The CO2 fixation and respiration rate increased with increasing total vegetation cover. The highest respiration and the highest CO2 fixation rates were found in sample plots dominated by mature Eriophorum vaginatum tussocks. Those sample plots were the only ones having positive CO2 balance. Regression analysis indicated that the respiration rate depended on soil temperature. Variation in the water table had no influence on the respiration or the C02 fixation rate.
Key words: CO2 balance, Eriophorum vaginatum, GNMDS, harvested peatland, plant colonization
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Tuittila,
Department of Forest Ecology, P.O. Box 24, FIN-00014 University of Helsinki, Finland
Sähköposti:
ei.tietoa@nn.oo
- Komulainen, Sähköposti: ei.tietoa@nn.oo
Turvepohjaisten kasvualustojen tiivistyminen yksivuotisessa paakkutaimikasvatuksessa.
English title: Compaction of growth media based on Sphagnum peat during one-year culturing of container seedlings.
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Changes in bulk density and water retention during one-year culturing of container seedlings were studied in pure, low-humified Sphagnum peat and in peat-based two-component growth media. In all growth media, the bulk density increased slightly with time. The corresponding decrease in total porosity was negligible (< 1 %-unit for pure peat). At matric potentials < -1 kPa, water retention of growth media tended to increase somewhat with time. On the other hand, shrinkage at desorption decreased during seedling culturing. The results suggest that, from the standpoint of seedling growth, the structure of growth media based on Sphagnum peat does not markedly change or deteriorate during one-year culturing of seedlings. However, in seedling culturing peat growth media containing hydrogel may possess restricted aeration due to excess water retention, while addition of coarse textured materials, such as perlite, to peat can increase aeration.
Key words: nursery management, soil physical properties, shrinkage, substrate, water retention
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Heiskanen,
The Finnish Forest Research Institute, Suonenjoki Research Station, FIN-77600 Suonenjoki, Finland
Sähköposti:
ei.tietoa@nn.oo
Hakkuiden tarve ja toteutuminen yksityismetsien kunnostusojitusalueilla Satakunnassa.
English title: The need for and realization of cuttings in connection with ditch network maintenance in private forests in Satakunta, southwest Finland.
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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
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Silver,
Satakunta District Forestry Board, Itsenäisyydenkatu 35 A, FIN-28100 Pori, Finland
Sähköposti:
ei.tietoa@nn.oo
- Saarinen, Sähköposti: ei.tietoa@nn.oo
Turvestratigrafisen tutkimuksen historiasta ja kvartaaritieteellisestä merkityksestä Pohjoismaissa.
English title: On the history and Quaternary scientific significance of peat stratigraphical research in the Nordic countries.
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The early development of peat stratigraphical research was concentrated in the Nordic countries. Although this field of science originated in Denmark at the beginning of the 19th century, the most important pioneer of palaeoecological peatland research was the Norwegian, Axel Blytt. His model, as modified by the Swedish scientist Rutger Sernander, spread throughout Europe and from there to other continents and has had a major impact on peat stratigraphy and Quaternary science. However, our present knowledge of the regional differences in postglacial vegetation and climate history speaks against the use of the Blytt-Sernander scheme outside southern Scandinavia. Especially, the compulsive application of the Blytt-Sernander scheme in the zoning of pollen diagrams has lead to distortions and erroneous interpretations.
Keywords: Nordic countries, peat stratigraphy, postglacial climate history, pollen analysis
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Seppä,
Department of Geography, Laboratory of Physical Geography, P.O. Box 9, FIN-00014 University of Helsinki, Finland
Sähköposti:
ei.tietoa@nn.oo
Sekakoivikon reaktio ensiharvennukseen mustikkaturvekankaalla Lapissa.
English title: Thinning response of a young, birch-dominated mixed stand on Vaccinium myrtillus peatland forest type in Lapland.
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The five-year response of a birch-dominated mixed stand (80% Betula pubescens, 14% Betula pendula) to thinning was studied in a thinning experiment in a mesotrophic, shallow-peated site in Ylitornio, northern Finland. Four thinning intensities (0%, 47%, 57% and 71 % removal of the initial stem number, i.e. 0%, 17%, 27% and 52% removal of the initial basal area), with three replications, were arranged in a randomized block design. At the time of thinning, the stand age was 30 a, and the dominant height was 11.5 m. Light (15%) and normal (27%) thinning decreased the rates of stand-level basal area growth by 12 and 15%, respectively. Thinning resulted in a significant increase in the growth of mean height and a subsequent increase in volume growth in the normally-thinned plots. Following heavy thinning, the volume and basal area growth rates were 35% and 32% less than those in the control treatment. The relative basal area increment, as well as the increase in mean diameter, was at its maximum in the heavily-thinned plots.
Keywords: Betula pubescens, forest drainage, growth, thinning
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Hökkä,
The Finnish Forest Research Institute, Rovaniemi Research Station, P.O.Box 16, FIN-96301 Rovaniemi, Finland
Sähköposti:
ei.tietoa@nn.oo
- Penttilä, Sähköposti: ei.tietoa@nn.oo
Väri-infrakuvat kunnostusojituksen kohdevalinnan tukena.
English title: Usability of infra red imagery in the planning of ditch network maintenance.
Avainsanat:
forest drainage;
biodiversity;
ditch cleaning;
environmental protection;
complementary ditching;
IR imagery;
decision making system
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The purpose of the study was to determine the usability of infra red imagery in evaluating the need for ditch network maintenance on nutrient-poor Scots pine mires. After interpreting a total of 75 tree stands in six peatland areas from the IR imagery, the stands were inventoried in the field. Site type, growing stock and ditch condition were determined. In addition, possible silvicultural treatments were suggested. Sphagnum fuscum, reddish-brown in the imagery indicated ditching areas unsuitable for ditch cleaning or complementary ditching. The estimated mean volumes of the tree stands were -37-+11% of the mean ground inventory values. The true proportions of tree species were in good agreement with the estimations based on the TR imagery. All in all, it was concluded that IR imagery is suitable in evaluating the need for ditch network maintenance on nutrient-poor mires. However, the validity of the method depended on the quality of the imagery and the skill of the interpreter.
Keywords: forest drainage, ditch cleaning, complementary ditching, IR imagery, decision making system, environmental protection, biodiversity
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Lauhanen,
The Finnish Forest Research Institute, Kannus Research Station,FIN-69101 Kannus, Finland
Sähköposti:
ei.tietoa@nn.oo
- Pietiläinen, Sähköposti: ei.tietoa@nn.oo
- Saarinen, Sähköposti: ei.tietoa@nn.oo
- Heikkinen, Sähköposti: ei.tietoa@nn.oo
Harvennushakkuun vaikutus pohjavedenpinnan syvyyteen ojitusalueilla Pohjois-Suomessa.
English title: Effect of thinning on groundwater table depth in drained peatlands in northern Finland.
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The effect of thinning on the groundwater table level was studied in four stands of Scots pine (Pinus sylvestris) on drained peatlands in northern Finland. Four thinning intensities (0-50% removal of the initial stocking), with three replications arranged using a randomized block design, were used in each experiment. If found to be in an unsatisfactory condition, the ditch networks were repaired at the time of thinning. Data from nine groundwater wells on each plot were used to determine the average depth of the groundwater table. The wells were monitored at two-week intervals during the latter parts of the growing seasons in 1991-1993. The mean groundwater table depth was used as the dependent variable in ANOVA with repeated measurements. In most cases, the groundwater table depth was lowest in the control plots, but significant differences between the treatments were found only in 1993 in two experiments. It was concluded that thinning caused no rise, or only a slight rise, in the groundwater table level.
Keywords: Forest drainage, groundwater table, Pinus sylvestris, thinning
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Hökkä,
The Finnish Forest Research Institute, Rovaniemi Research Station, P.O.Box 16, FIN-96301 Rovaniemi, Finland
Sähköposti:
ei.tietoa@nn.oo
- Penttilä, Sähköposti: ei.tietoa@nn.oo
Harvennusmenetelmien vertailu ojitetun turvemaan männikössä. Simulointitutkimus.
English title: Comparison of thinning methods in a Scots pine stand on drained peatland. A simulation study.
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The post-drainage growth of a simulated model stand according to different thinning methods was predicted for 84 years by spatial single-tree growth models. In thinnings, the post-thinning stand density varied as a function of the distance of the ditch. The best yield and income were obtained by leaving the stand near ditches and extraction road midway between ditches denser than elsewhere.
Keywords: growth model, Pinus sylvestris, stand management
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Miina,
University of Joensuu, Faculty of Forestry, P.O.Box 111, FIN-80101 Joensuu, Finland
Sähköposti:
ei.tietoa@nn.oo
- Pukkala, Sähköposti: ei.tietoa@nn.oo
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