Aleksey Fedorkov, Ludmila Gutiy. (2017). Performance of lodgepole pine and Scots pine in field trials located in north-west Russia. Silva Fennica vol. 51 no. 1 article id 1692. https://doi.org/10.14214/sf.1692

Keywords: Pinus sylvestris; stem defects; mortality; Pinus contorta; stem growth

Highlights: Stem volume was bigger for lodgepole pine in comparison to local Scots pine except for the southernmost origin; The proportion of stems with no defects was lower for all lodgepole pine seed sources than for local Scots pine; Lodgepole pine stem growth traits were significantly related to latitude of seed origin.

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

Mortality, stem growth and quality of lodgepole pine (Pinus contorta var. latifolia) originating from the six Swedish seed orchards and local Scots pine (Pinus sylvestris L.) were estimated in four field trials established in the Komi Republic (north-west Russia). A randomized row-plot design with 6–12 replicates of each entry was used. The tree mortality was slightly higher for Scots pine than that for lodgepole pine, except for the lodgepole pine seed sources of the southern origins with lower survival. Scots pine stem quality was better than that of lodgepole pine, but the lodgepole pine stem growth was faster except the seed source of the southernmost origin. The lodgepole pine seed sources of northern origins had better stem growth (height, diameter at breast height and volume), while the effect of latitude on the quality traits was insignificant.

Fedorkov, Institute of Biology, Komi Science Center, Russian Academy of Sciences, 28 Kommunisticheskaya st., Syktyvkar 167982, Russia http://orcid.org/0000-0001-7800-7534 E-mail: fedorkov@ib.komisc.ru
Gutiy, Syktyvkar Forest Institute (branch), Saint-Petersburg State Forest Technical University, 39 Lenin st., Syktyvkar 167000, Russia E-mail: lguti@mail.ru

article id 117, category Research article

Harri Kilpeläinen, Jari Lindblad, Henrik Heräjärvi, Erkki Verkasalo. (2011). Saw log recovery and stem quality of birch from thinnings in southern Finland. Silva Fennica vol. 45 no. 2 article id 117. https://doi.org/10.14214/sf.117

Keywords: Betula pendula; Betula pubescens; thinning; European white birch; silver birch; saw logs; stem quality; stem defects; bucking; recovery

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The objective of this study was to examine the timber quality of silver birch (Betula pendula Roth) and European white birch (Betula pubescens Ehrh.) trees in the first and second thinnings in southern parts of Finland, from the viewpoint of sawing of small-diameter, short logs, in particular. The average stem volume of birch was 0.140 m³ in the first thinning stands and 0.206 m³ in the second thinning stands. In planted stands, the trees were larger in the first thinnings but slightly smaller in the second thinnings, compared with naturally regenerated pure birch stands or mixed stands of Norway spruce and birch species. Almost 60% of the harvested and 35% of the remaining stems that could provide saw logs were graded as pulpwood for timber quality due to the occurrence of stem defects. The most common stem defects were multiple crooks and middle crooks. Only minor between-stratum differences were detected in the numbers of defects. Depending on the bucking option, the total percentage of saw and plywood logs from the total birch recovery in the thinning of the sample stands varied between 11.7 and 18.2. The recovery of saw logs was clearly higher in the second thinnings, 12–19%, than in the first thinnings, 8–14%. Of the stand types, saw log recovery was the highest in planted birch stands, 12–19%, but lower in naturally regenerated pure birch stands and mixed stands of Norway spruce and birch. The highest share of saw logs was in the second thinning of planted stands, 17–25%. This study shows that the harvesting recoveries of end-use based timber assortments can be estimated in different kinds of thinning birch stands. Based on tree and log dimensions and stem squality, silver birch firstly from plantations and secondly from mixed stands should be the most interesting source of raw material for the saw milling, furniture and interior product sectors.

Kilpeläinen, Finnish Forest Research Institute, Eastern Finland Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: hk@nn.fi
Lindblad, Finnish Forest Research Institute, Eastern Finland Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: jl@nn.fi
Heräjärvi, Finnish Forest Research Institute, Eastern Finland Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: henrik.herajarvi@metla.fi
Verkasalo, Finnish Forest Research Institute, Eastern Finland Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: ev@nn.fi

article id 226, category Research article

Anneli Viherä-Aarnio, Pirkko Velling. (2008). Seed transfers of silver birch (Betula pendula) from the Baltic to Finland – effect on growth and stem quality. Silva Fennica vol. 42 no. 5 article id 226. https://doi.org/10.14214/sf.226

Keywords: Betula pendula; yield; provenance; climatic adaptation; stem defect

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Silver birch (Betula pendula Roth) seed origins from the Baltic countries, Finland and Russia were compared for survival, growth and stem quality, and the effect of latitudinal seed transfer distance examined in two provenance trials. The trials were located on moist upland forest soils at Tuusula (60°21’N) in southern Finland and at Viitasaari (63°11’N) in central Finland. The material consisted of 21 stand and single tree origins ranging from latitudes 54° to 63°N. Survival, height, dbh, relative stem taper, stem volume/ha and the proportion of trees with a stem defect (vertical branch or forked stem), were assessed when the trees were 22 years old. Significant differences were detected among the origins regarding all the measured traits in both trials. Southern Finnish origins produced the highest volume per unit area in central Finland, whereas Estonian and north Latvian stand seed origins, as well as the southern Finnish plus tree origins, were the most productive ones in southern Finland. The more southern the origin, the higher was the proportion of trees with a stem defect in both trials. The latitudinal seed transfer distance had a significant but relatively small effect on survival, stem volume/ha and proportion of trees with a stem defect. The proportion of trees with a stem defect increased linearly in relation to the seed transfer distance from the south. The relationship of both survival and stem volume/ha to the seed transfer distance was curvilinear. Volume/ha was increased by transferring seed from ca. 2 degrees of latitude from the south. A longer transfer from the south, as well as transfer from the north, decreased the yield.

Viherä-Aarnio, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: anneli.vihera-aarnio@metla.fi
Velling, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: pv@nn.fi

Category : Research note

article id 24039, category Research note

Jussi Manner, Hagos Lundström. (2024). The effect of forked trees on harvester time consumption in a Pinus contorta final-felling stand. Silva Fennica vol. 58 no. 4 article id 24039. https://doi.org/10.14214/sf.24039

Keywords: productivity; stem quality; stem defect; lodgepole pine; cut-to-length logging; double stem; forking

Highlights: For forked trees, codominant stems double harvester time consumption per tree, while double crowns have only minor impacts on harvester time consumption; Forked trees should be removed during thinning when they can still be time-efficiently multi-tree handled; Dealing with forked trees at a later rotation age, when they are too large for multi-tree handling, becomes excessively time-consuming.

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

The consensus on the factors affecting harvester productivity is generally widely acknowledged in the discipline. However, research results regarding the effect of forking on productivity are diverse. Some studies show that harvester productivity is halved when harvesting double stems compared to single-stem trees, while other studies indicate that forking does not necessarily decrease harvester productivity. These differences in study results can depend on what is considered forking. In our study, the forking occurred above the breast-height level. We defined codominant stems as forked trees too large to be multi-tree handled. In contrast, we defined double crowns as forked trees that could be multi-tree handled. The objective of our study was to analyse how the presence of codominant stems and/or double crowns affects harvester time consumption. The study was conducted in Sweden in 2022, involving two operators and two large harvesters. The 45-year-old Pinus contorta Douglas ex Loudon-dominated stand was clearcut during the study. We found that the presence of codominant stems doubles harvester time consumption per tree, while double crowns had only a minor impact on harvester time consumption. Additionally, total time consumption increased linearly with increasing diameter at breast height. Based on these findings, we recommend that forked trees be removed already during thinning when they can still be time-efficiently multi-tree handled. Dealing with forked trees later during the rotation cycle, when they are too large for multi-tree handling, is excessively time-consuming.

Manner, Skogforsk, Uppsala Science Park, 751 83 Uppsala, Sweden https://orcid.org/0000-0002-4982-3855 E-mail: jussi.manner@skogforsk.se
Lundström, Skogforsk, Uppsala Science Park, 751 83 Uppsala, Sweden E-mail: hagos.lundstrom@skogforsk.se

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