Suo - Mires and peat vol. 46 no. 1 | 1995
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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