Current issue: 53(3)

Under compilation: 53(4)

Impact factor 1.683
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Silva Fennica 1926-1997
1990-1997
1980-1989
1970-1979
1960-1969
Acta Forestalia Fennica
1953-1968
1933-1952
1913-1932

Articles containing the keyword 'puuston kasvu'.

Category: Article

article id 7117, category Article
Leo Heikurainen. (1961). Metsäojituksen vaikutuksesta puuston kasvuun ja poistumaan hakkuusuunnitteiden laskemista varten. Acta Forestalia Fennica vol. 71 no. 8 article id 7117. https://doi.org/10.14214/aff.7117
English title: The influence of forest drainage on growth and removal in Finland. For estimations of allowable cut.

The Finnish forest industry is undergoing a vast expansion, which has raised questions of forest balance. This paper studies the possibilities to increase the amount available timber by means of forest drainage. About third of the Finnish land area is peatlands. The calculations of the investigation are based on Forestry Board districts. Based on earlier studies, there is estimated to be 3,042,000 ha of true drainable swamps, 973,000 ha of poor swamps, 1,381,000 ha of uplands in need of drainage, and 1,205,000 ha of drained peatlands. Therefore, the area of drainable and drained lands totals 6,6 million ha, and requirement of forest drainage 5,4 million ha. The drainage hardly reaches this extent, however. It can be assumed that part of the poor swamps is uneconomical to drain. In addition, a half of the paludified forest land will probably not be drained. Thus, it can be estimated that the area to be drained in the future is about 5 million ha. It seems possible that this area could be drained within about 50 years with the present draining capacity.

Draining of all objects of forests would increase the annual increment of our forests, in time, by about 10.5 million m3. This would signify an increase of 23% compared to the present growth of the forests. The increase in the growth consists mainly of softwood: 16% is birch, and the remaining 84% almost equally of Scots pine and Norway spruce. The increase of growth is relatively slow. Depending on the rate of the drainage program, the mean increase of growth will be reached in about 25–35 years. The increase in removal indicated by the increase in the mean increment will be reached in only 50–60 years.

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  • Heikurainen, ORCID ID:E-mail:
article id 4836, category Article
Erkki Lähde. (1971). Anaerobisten olosuhteiden ja aerobisuusrajan esiintymisestä erilaisilla luonnontilaisilla turvemailla ja merkityksestä suotyypin kuvaajana. Silva Fennica vol. 5 no. 1 article id 4836. https://doi.org/10.14214/sf.a14625
English title: Anaerobic conditions in various virgin peat soils and the significance of the aerobic limit as an indicator of site quality.

The aim of the present study was to increase the knowledge of the anaerobic conditions prevailing in virgin peat soils of different kinds, and on the fluctuation of the aerobic limit. Silver rod method was used to indicate anaerobic conditions and to locate the aerobic limit. The material included 18 peatland sample plots on treeless bogs, in pine bogs and in spruce swamps in Southern Finland. Observations of the discoloration of the silver rods and measurements of ground water level were made from 8 June to 13 August 1968.

The results show that the location of the aerobic limit is dependent of the depth of the ground water table, and usually lies 5–15 cm above the ground water table. Down to 10–20 cm below the aerobic limit, where it reaches maximum, the rate of decomposition of sulfurous organic matter is positively correlated with the distance from the aerobic limit. Deeper it gradually decreases, and in the depth of 25–35 cm no hydrogen sulphide seems to be released.

In the forested peatland types the volume of the growing stock and the increment were dependent on the depth of the aerobic limit only when nutrient content and pH of the peat was more or less constant. Where the aerobic limit was close to the ground surface but the nutrient contents were relatively high, the volume of the growing stock may be comparatively high. Birch (Betula sp.), better than the conifers, is able to stand conditions poor in oxygen. The growing stock was poor in sites where the aerobic limit was near the ground surface, but the nitrogen and phosphorus contents were high, or vice versa. Consequently, aerobic limit is of great importance as an indicator of site quality.

The PDF includes a summary in English.

  • Lähde, ORCID ID:E-mail:

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