Yrjö Nuutinen, Jari Miina, Timo Muhonen, Janne Uuttera, Heikki Ovaskainen. (2026). Comparing the characteristics, removals and incomes of zone- and low-thinned stands of Norway spruce. Silva Fennica vol. 60 no. 2 article id 26007. https://doi.org/10.14214/sf.26007

Keywords: Picea abies; peatland; simulation; first thinning; hpr-data; thinning removal

Highlights: At the first thinning stage, zone thinning resulted in lower removals and incomes than low thinning; The total removal and income from the first thinning and subsequent simulated cuttings did not differ between thinning treatments; Zone thinning is a feasible option for the first thinning; On peatland, zone thinning would diversify stand structure and encourage natural regeneration.

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

Zone thinning is designed to improve harvesting productivity in the first commercial thinning and facilitate the transition to continuous cover forestry by encouraging natural regeneration. In zone thinning, the density of the remaining stand varies between strip roads 30 m apart, from heavily thinned roadside zones to untreated zones >10 m from the road. In the subsequent thinning, strip roads are opened in the untreated zones. This study first compared the characteristics and removals of Norway spruce (Picea abies (L.) H. Karst.) dominated stands after zone and low thinning. Thinning treatments were applied in two planted stands on mineral soil at the first commercial thinning stage, and in two advanced thinning stands on drained peatlands. The harvested removals were obtained from the harvester records. Secondly, the post-treatment development and removal of the experimental plots were predicted using a distance-dependent, individual-tree simulator that had been developed for spruce-pine (Pinus sylvestris L.) mixtures. On zone-thinned plots of young thinning stands, the number of stems per ha was significantly higher, and the amount harvested was significantly lower, compared to low-thinned plots. In advanced thinning stands, the stand basal area and volume were higher on zone-thinned plots than on low-thinned plots. Total removals (harvested and simulated) and cutting incomes during the rotation period did not differ between zone and low thinning treatments. This suggests that zone thinning could be used for the first thinning without reducing timber production or revenues.

Nuutinen, Natural Resources Institute Finland (Luke), Yliopistokatu 6B, FI-80101 Joensuu, Finland https://orcid.org/0000-0003-3360-4444 E-mail: yrjo.nuutinen@luke.fi
Miina, Natural Resources Institute Finland (Luke), Yliopistokatu 6B, FI-80101 Joensuu, Finland https://orcid.org/0000-0002-8639-4383 E-mail: jari.miina@luke.fi
Muhonen, E-mail: tmuhonen@saunalahti.fi
Uuttera, UPM Forest, Vankanlähde 7, FI-13100 Hämeenlinna, Finland E-mail: janne.uuttera@upm.com
Ovaskainen, https://orcid.org/0000-0001-5063-6662 E-mail: heikki.ovaskainen1@gmail.com

article id 10462, category Research article

Yrjö Nuutinen, Jari Miina, Timo Saksa, Dan Bergström, Johanna Routa. (2021). Comparing the characteristics of boom-corridor and selectively thinned stands of Scots pine and birch. Silva Fennica vol. 55 no. 3 article id 10462. https://doi.org/10.14214/sf.10462

Keywords: biomass; forestry; first thinning; geometrical thinning; systematic thinning

Highlights: After boom-corridor thinning (BCT), the number of stems per hectare was higher than that after selective thinning. The number of future crop trees was at the same level; The removal of the simulated intermediate thinnings and clearcutting in BCT treatments was 10–18% higher than in selective thinning. The saw log volumes were at the same level in both treatments.

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

Young, dense forest in Finland and Sweden urgently need to receive first thinning. In such stands, conventional selective thinning methods make the harvester work time consuming and, thus, costly. To make small-sized trees economically competitive as raw material for bioenergy and biorefining, new harvesting technologies and/or thinning methods need to be developed. A potential solution is boom-corridor thinning (BCT), rendering effective cutting work. The aim of this study was to describe and compare the stand structure of two Scots pine stands (Pinus sylvestris L.) and one birch-dominated (Betula pendula Roth with natural downy birch, B. pubescens Ehrh.) stand after BCT and selective thinning at the first thinning phase. Furthermore, simulations were conducted to predict the future stand development after the first thinning treatments. The density of the growing stock was 16–46% higher after BCT treatment than after selective thinning because BCT stands included more small and supressed trees with a dbh < 100 mm. However, the numbers of future crop trees with a dbh > 140 mm per hectare were at the same level in both treatments. The stem volume removal per hectare did not differ between treatments. However, simulation of stand development and intermediate thinning and clearcutting revealed that the total removal volume was 10–18% higher in BCT stands compared to selectively thinned ones. The saw log volumes harvested did, however, not differ between treatments. This study shows that BCT generates stands with higher biodiversity compared to conventional thinning as higher levels of biomass removal can be reached throughout stand rotations.

Nuutinen, Natural Resources Institute Finland (Luke), Production systems, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: yrjo.nuutinen@luke.fi
Miina, Natural Resources Institute Finland (Luke), Natural resources, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: jari.miina@luke.fi
Saksa, Natural Resources Institute Finland (Luke), Natural resources, FI-77600 Suonenjoki, Finland E-mail: timo.saksa@luke.fi
Bergström, Swedish University of Agricultural Sciences (SLU), Dept of Forest Biomaterials and Technology, Section of Forest Operations, SE-90183 Umeå, Sweden E-mail: dan.bergstrom@slu.se
Routa, Natural Resources Institute Finland (Luke), Production systems, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: johanna.routa@luke.fi

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