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Articles containing the keyword 'ditch depth'

Category : Article

article id 7468, category Article
Leo Heikurainen. (1957). Metsäojien syvyyden ja pintaleveyden muuttuminen sekä ojien kunnon säilyminen. Acta Forestalia Fennica vol. 65 no. 5 article id 7468. https://doi.org/10.14214/aff.7468
English title: Changes in depth and top width of forest ditches and the maintaining of their repair.
Original keywords: ojitus; metsäojitus; suot; ojat; ojien kunto; ojansyvyys
English keywords: drainage; peatlands; draining of peatlands; ditches; ditch depth; ditch repair
Abstract | View details | Full text in PDF | Author Info

The article deals with forest ditches dug by manual labour in drained peatlands in Central and Southern Finland, ranging in age from 16 to 25 years. The ditches have been allowed to develop in a natural state. A total 1,160 of randomly selected sample plots were studied.

The results show that the originally dug ditch depth has not been the decisive factor from the viewpoint of maintaining the ditch repair. Ditches dug in thick peat layer have maintained their repair better than those dug in thin peat layer. Apparently, the influencing factor is the type of soil, to a certain extent parallel to the thickness of peat layer. In ditches dug mainly in mineral soil, the type of soil has essentially contributed to maintaining the ditch repair. Ditches in coarse-grained soils maintained a better repair than those in fine-grained soils. Also, the steeper the gradient of the ditch the better the ditch repair has been maintained. There was no relationship between the thickness of peat and the filling up of ditch bottom, because of the influence of mineral soil. Filling up of a ditch seems to be mainly due to the sinking of peat. The filling up of ditch bottom was more pronounced in clay-silt soil than in other soil types. The filling up of ditch bottom by varying gradient is due to the fact that with a small gradient the speed of water is so slow as to permit the soil particles to sink to the bottom. Another factor affecting filling up of the ditches is wetness of the peatland. Deepening of ditches happens mainly through erosion, if the gradient is large enough. The study suggests that a 50-m spacing with about 60-cm ditchc depth would be most profitable.

The PDF includes a summary in English.

  • Heikurainen, E-mail: lh@mm.unknown (email)
article id 7614, category Article
Leo. Heikurainen. (1980). Kuivatuksen tila ja puusto 20 vuotta vanhoilla ojitusalueilla. Acta Forestalia Fennica no. 167 article id 7614. https://doi.org/10.14214/aff.7614
English title: Drainage condition and tree stands on peatlands drained 20 years ago in Finland.
Original keywords: mänty; tilavuuskasvu; ojitetut suot; sarkaleveys; ojien kunto; pohjaveden pinta; ojasyvyys
English keywords: Pinus sylvestris; Scots pine; stand volume; ditch spacing; ditch depth; volume increment; groundwater depth; ditch condition
Abstract | View details | Full text in PDF | Author Info

The aim of this investigation was to examine the dependence of stand volume and increment on different growth factors on drained peatlands drained 20 years ago. Measurements were made in 1977-79 on 35 sample plots in Central Finland on relatively poor pine bogs with a thick peat layer.

It became evident that the stand volume, increment and radial growth and growth development are primarily functions of groundwater depth. Groundwater depth is dependent, in the first place, on ditch depth and ditch condition. With regard to the variation in ditch spacing (ca. 35-70 m) under examination, the effect of ditch spacing on the stand was insignificant. As a practical recommendation it was concluded that ditches should be kept deep enough (> 70 cm) in order to maintain undisturbed stand development.

The PDF includes a summary in English.

  • Heikurainen, E-mail: lh@mm.unknown (email)

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