Artikkelit jotka sisältää sanan 'ditch cleaning'

Risto Lauhanen, Erkki Ahti. Kunnostusojituksen vaikutus rämemänniköiden kehitykseen.
English title: Effects of maintaining ditch networks on the development of Scots pine stands.
Avainsanat: forest drainage; peatland; ditch cleaning; complementary ditching; tree stand; Pinus sylvestris L.; volume growth
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This study aimed at finding out the effects of maintaining ditch systems by ditch cleaning and complementary ditching on volume growth of drained Scots pine (Pinus sylvestris L.) stands. Volume growth during the first ten post-treatment years was increased by 0.16 m3 ha-1 a-1 after ditch cleaning, 0.36 m3 ha-1 a-1 after complementary ditching, and 0.48 m3 ha-1 a-1 after the combined treatment. The average growth reactions during the second five-year period were considerably higher than during the first one. No drastic reductions in stand growth, however, occurred in the untreated plots during the post-treatment period of ten years.
  • Lauhanen, The Finnish Forest Research Institute, Kaironiementie 54, FIN-39700 Parkano, Finland Sähköposti: ei.tietoa@nn.oo (sähköposti)
  • Ahti, Sähköposti: ei.tietoa@nn.oo
Juhani Päivänen, Sakari Sarkkola. The effect of thinning and ditch network maintenance on the water table level in a Scots pine stand on peat soil.
Avainsanat: forest drainage; peatland; hydrology; ditch cleaning; complementary ditching; tree harvesting
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The effect of tree stand thinning and ditch network maintenance on the water table level was studied in an uneven-aged Scots pine (Pinus sylvestris L.) stand growing on a drained dwarf shrub pine bog in southern Finland. The water table level was monitored once a week during the growing seasons (May–September) of 1991–1999. This time span is divided into the following treatment periods: calibration (1991–1992), thinning (1993–1994), ditch cleaning (1995), and proper ditch network maintenance (1996–1999). The growing season of 1995 was not included in the calculations because the ditch cleaning treatment failed. The layout included three thinning intensities (9.5, 15.0, and 28.1% removal of the initial stand volume) and an unthinned control. For the ditch maintenance treatment there was an additional control sample plot. The effect of the treatments on the water table level was evaluated both by a graphical approach and linear regression analysis. Only a slight, ecologically insignificant rise in the water table level was caused by the thinning cuttings. Ditch maintenance seemed to eliminate this change. It was concluded that in the planning stage, a careful evaluation of the real need of maintaining the ditch network (ditch cleaning or complementary ditching) should be done in connection with the first commercial thinning in order to avoid unnecessary costs.
  • Päivänen, Department of Forest Ecology, Box 24, FIN-00014 Helsinki University, Finland Sähköposti: ei.tietoa@nn.oo (sähköposti)
  • Sarkkola, Sähköposti: ei.tietoa@nn.oo
Risto Lauhanen, Seppo Kaunisto. Kunnostusojituksen vaikutus rämeiden ravinnetilaan.
English title: Effect of drainage maintenance on the nutrient status on drained Scots pine mires.
Avainsanat: forest drainage; peat; Scots pine; ditch cleaning; complementary ditching; nutrients; needles
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The effects of drainage maintenance on the nutrient contents in peat and Scots pine needles on drained pine mires were studied. The material consisted of twelve Finnish field experiments. Drainage maintenance (increasing ditching intensity; no treatment at all, mere ditch cleaning, mere complementary ditching, and both of them together) was carried out in 1982-1985. The needles were sampled in 1994-1995 and peat in 1996. There were great differences in the site types and consequently also in the peat and needle nutrient concentrations between the experiments. The needle Mn concentrations demonstrated a fairly good drainage status in all the treatments. Drainage maintenance had only minor effects on the nutrient status of peat and needles. Ditch cleaning decreased magnesium, manganese and zink amounts in the surface peat. Increasing the intensity of drainage maintenance increased the 100-needle dry mass, but decreased the needle boron concentrations. Peat and needle nitrogen concentrations increased slightly (not significantly) along with the increased intensity in drainage maintenance. The peat nutrients classified correctly 83.7% of the fertility classes for drained peatlands.
  • Lauhanen, The Finnish Forest Research Institute, Kaironiementie 54, FIN-39700, Parkano, Finland Sähköposti: ei.tietoa@nn.oo (sähköposti)
  • Kaunisto, Sähköposti: ei.tietoa@nn.oo
Risto Lauhanen, Marja-Leena Piiroinen, Timo Penttilä, Eero Kolehmainen. Kunnostusojitustarpeen arviointi Pohjois-Suomessa.
English title: Evaluation of the need for ditch network maintenance in northern Finland.
Avainsanat: forest drainage; ditch cleaning; complementary drainage; tree stand; stand growth; decision making
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Factors affecting the need for ditch network maintenance in northern Finland were studied. In addition, the effect of ditch network maintenance on stand growth was estimated. A dataset containing ditch, tree stand, site type and climate variables was built up on the basis of the permanent sample plots (SINKA) on peatlands. Regression analysis as well as discriminant analysis were used to identify factors and criteria that could be used to identify sites that would respond to ditch network maintenance. Instead of the ditch condition class, ditch age and depth proved to be the variables reflecting the need for ditch network maintenance. The volume of the tree stand was influenced the most by the temperature sum and age of ditching. Stand volume growth was influenced the most by the volume of the tree stand. The site type index or the volume of the tree stand did not give useful information for the planning of ditch network maintenance. When ditch age was 10-40 years, complementary ditching increased annual stand growth of pine mires by 0.6-1.0 and 1.5-1.9 m3 ha-1 a-1 on spruce-birch swamps.
  • Lauhanen, The Finnish Forest Research Institute, Parkano Research Station, FIN-39700 Parkano, Finland Sähköposti: ei.tietoa@nn.oo (sähköposti)
  • Piiroinen, Sähköposti: ei.tietoa@nn.oo
  • Penttilä, Sähköposti: ei.tietoa@nn.oo
  • Kolehmainen, Sähköposti: ei.tietoa@nn.oo
Timo Silver, Markku Saarinen. 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.
Avainsanat: peatlands; ditch cleaning; cuttings
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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
  • Silver, Satakunta District Forestry Board, Itsenäisyydenkatu 35 A, FIN-28100 Pori, Finland Sähköposti: ei.tietoa@nn.oo (sähköposti)
  • Saarinen, Sähköposti: ei.tietoa@nn.oo
Risto Lauhanen, Pekka Pietiläinen, Markku Saarinen, Eljas Heikkinen. 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
  • Lauhanen, The Finnish Forest Research Institute, Kannus Research Station,FIN-69101 Kannus, Finland Sähköposti: ei.tietoa@nn.oo (sähköposti)
  • Pietiläinen, Sähköposti: ei.tietoa@nn.oo
  • Saarinen, Sähköposti: ei.tietoa@nn.oo
  • Heikkinen, Sähköposti: ei.tietoa@nn.oo
Risto Lauhanen. Kaivukaluston aiheuttamat puustovauriot kunnostusojituksessa.
English title: Tree damage caused by excavating machines in ditch network maintenance.
Avainsanat: forest drainage; excavator; ditch cleaning; work studies; backhoe; ditch digging; environmental protection
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An inventory of tree damage caused by five excavators, four backhoes and one small-size single-track backhoe was carried out in western Finland during the frost free season. The proportion of damaged trees was 1.1-2.4 % in tree stands ditched using backhoes and excavators, if the ditch lines had been opened in advance. The corresponding proportion caused by the single-track backhoe was 0.9%, if the ditch lines had not been opened in advance. The damage to tree stands was affected by the machine type, the work type and the width of the opened ditch line. Excavators caused more stem damage in the ditch cleaning than backhoes did (p<0.02). The mean distances of the damaged trees from the center line of the ditch were 226-264 cm on the work sites ditched using backhoes and excavators. The mean DBH of the damaged trees was 8-10 cm depending on work and machine type. The optimum width of the ditch line for the different machine types was assumed to be 400-500 cm when considering the growth losses of tree stand, the tree damage and the work productivity. Keywords: backhoe, ditch cleaning, ditch digging, environmental protection, excavator, forest drainage, work studies R. Lauhanen, The Finnish Forest Research Institute, Kannus Research Station, FIN-69101 Kannus, Finland
  • Lauhanen, The Finnish Forest Research Institute, Kannus Research Station, FIN-69101 Kannus, Finland Sähköposti: ei.tietoa@nn.oo (sähköposti)
Risto Lauhanen. Kaivukaluston tuottavuus, työnjalki ja kustannukset kunnostusojituksessa.
English title: The productivity, work quality and the costs of employing backhoes and excavators in ditch network maintenance.
Avainsanat: forest drainage; additional ditching; ditch cleaning; excavating machines; work studies
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Four backhoes and four excavators were studied in different excavation difficulty classes (1-5) during the unfrozen period in the western part of Finland. The productivity (per effective hour) of the backhoes in ditch digging (additional ditching) was 54-172 m/h and 68-202 m/h in ditch cleaning. The productivity of the excavators was 114-289 m/h and 88-250 m/h, respectively. Productivity decreased as the difficulty class increased. It was affected by the width of the ditch line opening, the stoniness, and ditch depth. Productivity seemed to be affected by the machine operator, too. The work quality was acceptable. The operating costs were 268-388 FIM per hour for the machines costing 400 000-1000 000 FIM. Key words: additional ditching, ditch cleaning, excavating machines, forest drainage, work studies
  • Lauhanen, The Finnish Forest Research Institute, Kannus Research Station, FIN-69100 Kannus, Finland Sähköposti: ei.tietoa@nn.oo (sähköposti)

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