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Articles by Unto Väisänen

Category : Article

article id 4755, category Article
Unto Väisänen. (1967). Puun korjuu. Silva Fennica vol. 1 no. 3 article id 4755. https://doi.org/10.14214/sf.a14539
English title: Book review: Harvesting Timber Crops.
Keywords: book review
Abstract | View details | Full text in PDF | Author Info

This article is a book review of a textbook ’Harvesting Timber Crops’ by A.E. Wackerman, W.D. Hagenstein and A.S. Mitchell.

  • Väisänen, E-mail: uv@mm.unknown (email)

Category : Article

article id 7613, category Article
Pekka Kilkki, Unto Väisänen. (1969). Determination of the optimum cutting policy for the forest stand by means of dynamic programming. Acta Forestalia Fennica no. 102 article id 7613. https://doi.org/10.14214/aff.7613
Keywords: thinnings; density; fellings; thinning from below; rotation; thinning from above; cutting program
Abstract | View details | Full text in PDF | Author Info

The purpose of this study was determining the optimum cutting program for forest stands by the application of dynamic programming. Calculations have been made for even-aged Scots pine (Pinus sylvestris L.) stands in Southern Finland, aged 50-100 years. Three logging cost levels, thinning from below and from above, and rates of interest of 1, 2, 3, 4, and 5% was applied. Both optimum routes and the economic results of different cutting programs was analysed.

According to the results, the higher the rate of interest is, the lower the density remains, and shorter the rotation is. The starting level of the growing stock may influence the treatment of the stand for tens of years. If logging costs change, so that harvesting small wood becomes relatively more expensive in the future, the density of growing stock will increase. However, heavy thinnings today are recommendable, to avoid expensive thinnings in the future.

The density of the growing stock should be higher if thinning from above is applied, instead of thinning from below. The growth of the stands thinned from below needs to be greater than the growth of stands thinned from above, to justify thinnings from below. Too high density often results in larger losses than do too low a density or the wrong rotation. Thinnings seem to be profitable even at much higher logging costs than those of today. The maturity of the stand is determined both by the age and the density of the growing stock. The stand may be mature because of great age, high density combined with a relatively high age, or because the growing stock is too low in density.

The PDF includes a summary in Finnish.

  • Kilkki, E-mail: pk@mm.unknown (email)
  • Väisänen, E-mail: uv@mm.unknown

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