This study is concerned with silvicultural selection from above. The material consists of 18 Scots pine (Pinus sylvestris L.) sample plots in the southern half of Finland in experimental forests. The method is motivated by the great difference between the stumpage prices of saw timber and pulpwood. The method suggested includes the removal of individuals belonging to the predominating canopy, to achieve high levels of income from the stand at an early stage. The method is applied at when the growing stock is attaining saw-timber size. Before that the stand is treated with thinnings from below. It is supposed that the volume of growing stock is maintained at a level as high as that in below-thinned stands, and that rotation is of normal length.

On the average, the increment in basal area, as well as volume increment, is greater in stands selectively cut from above than in those treated with low thinnings of the same degree. Initially, selection from above seems to exert a negative effect upon the development of dominant height; later, the dominant height reassumes the same rate of increment as in the below-thinned stands. Selection from above also means an increase in saw-timber production, although it involves a reduction in the mean size of saw timber. The investigation includes growth and yield tables for pine stands treated with silvicultural selection from above.

The results of the investigation prove that silvicultural selection from above is at least as profitable as low thinning. This provides freedom for stand treatment, and contributes to the application of a method most suitable for the owner in each individual case. It is further stressed that the maintenance of a high wood capital in the stand is far more important than the method of thinning applied.

The PDF includes a summary in English.

Vuokila, E-mail: yv@mm.unknown

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
Väisänen, E-mail: uv@mm.unknown

Category : Research article

article id 25061, category Research article

Juha-Pekka Hotanen, Jari Miina, Leila Korpela, Raisa Mäkipää. (2026). Effects of selection harvesting on the understorey vegetation in drained Norway spruce peatlands. Silva Fennica vol. 60 no. 1 article id 25061. https://doi.org/10.14214/sf.25061

Keywords: continuous cover forestry; ground vegetation; thinning from above; ANOVA; uneven-aged cutting

Highlights: The thinning intensity and time since harvest significantly affect vegetation dynamics on fertile, drained Norway spruce peatlands; Several species respond to the thinning intensity, showing a greater treatment effect with more time since thinning; Vaccinium myrtillus increases, especially on the most intensively thinned plots; Selection harvesting has a minor effect on the number of plant species in drained Norway spruce peatlands.

Abstract | Full text in HTML | Full text in PDF | Author Info

This study focused on the changes in species abundance after harvest in uneven-aged stands. Selection harvesting was performed at four sites in southern boreal vegetation zones in Finland using two thinning intensities: post-harvest basal area (G) of 17 and 12–13 m² ha^–1. The G pre-harvest and in control plots varied between 19 and 31 m² ha^–1. Vegetation was inventoried before thinning in 2016 and 2 and 6 years after thinning in 2018 and 2022. The effect of thinning intensity was significant for grasses and sedges as groups, Betula pubescens Ehrh. (height < 50 cm), Rubus idaeus L., and Trientalis europaea L., which showed increased abundance after harvest. However, T. europaea abundance turned to decline by 2022. Several species responded to the thinning intensity, showing a greater treatment effect with the more time since harvest. The abundance of Carex globularis L., Dryopteris carthusiana (Vill.) H.P. Fuchs, Epilobium angustifolium L., Vaccinium myrtillus L., V. vitis-idaea L., Linnaea borealis L. and Brachythecium spp. increased, but that of Oxalis acetosella L. decreased. For some species, only the time since harvest was significant. The abundance of Maianthemum bifolium (L.) F.W. Schmidt, Deschampsia flexuosa (L.) Trin. and Plagiothecium spp. increased, whereas that of Sphagnum girgensohnii Russow and S. russowii Warnst. decreased. The thinning intensity did not have a significant effect on the number of species, but the number of species increased slightly on the thinned plots. The effects of logging residues, strip roads, and light availability may be the major drivers of the changes in the species abundance.

Hotanen, Natural Resources Institute Finland (Luke), Yliopistokatu 6 B, FI-80100 Joensuu, Finland E-mail: ext.juha-pekka.hotanen@luke.fi
Miina, Natural Resources Institute Finland (Luke), Yliopistokatu 6 B, FI-80100 Joensuu, Finland https://orcid.org/0000-0002-8639-4383 E-mail: jari.miina@luke.fi
Korpela, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland https://orcid.org/0000-0001-9900-4332 E-mail: ext.leila.korpela@luke.fi
Mäkipää, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland https://orcid.org/0000-0003-3146-4425 E-mail: raisa.makipaa@luke.fi

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