Category :
Article
article id 5525,
category
Article
Jari Miina.
(1994).
Spatial growth model for Scots pine on drained peatland.
Silva Fennica
vol.
28
no.
1
article id 5525.
https://doi.org/10.14214/sf.a9159
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A spatial growth model is presented for Scots pine (Pinus sylvestris L.) on a dwarf-shrub pine mire drained 14 years earlier. The growth model accounts for the variation in tree diameter growth owing to the competition between trees, the distance between tree and ditch, and the time passed since drainage. The model was used to study the effect of tree arrangement on the post-drainage growth of a pine stand. Clustering of trees decreased the volume growth by 9–20% as compared to a regular spatial distribution. Stand volume growth, for a given number of stems, was at its maximum and variation in diameter growth at its minimum when the stand density on the ditch border was 1.5–5 higher than midway between two adjacent ditches.
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Miina,
E-mail:
jm@mm.unknown
Category :
Climate resilient and sustainable forest management – Research article
article id 23075,
category
Climate resilient and sustainable forest management – Research article
Lauri Männistö,
Jari Miina,
Saija Huuskonen.
(2024).
How to utilize natural regeneration of birch to establish mixed spruce-birch forests in Finland?
Silva Fennica
vol.
58
no.
3
article id 23075.
https://doi.org/10.14214/sf.23075
Highlights:
Naturally emerging birch admixture provides a sufficient starting point for mixed forest in young, planted spruce stands; Creating mixed forest is a time sensitive process, as different growth patterns among tree species might cause a situation where one tree species suppresses the other, leading to monoculture or two-storied mixed forest; Birch admixture should be retained during early cleaning.
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Mixed forests are known for their ability to provide a wide range of ecosystem services. Such forests have higher biodiversity compared to monocultures, are resilient against disturbances and may mitigate the effects of climate change. Despite well-known benefits, there is still little information on how these forests should be established and managed. The aim of this study was to describe the early growth dynamics of current boreal young mixed stands of planted Norway spruces (Picea abies (L.) Karst.) and naturally regenerated birches (Betula spp.). We collected data from 9 stands planted for spruce 8–14 years ago in Southern and Central Finland. Stem analysis was conducted to 144 spruces and to 144 birches to determine previous growth. We modelled the height and diameter development of individual trees in relation to tree age at stump height using non-linear mixed Chapman-Richards model. There were no significant differences between spruce and seed-origin birch in diameter growth at stump height, but the initial height increments of natural birches were larger than those of planted spruces. However, planted spruces were able to keep up with the height development of birches, if spruces received a head start over naturally regenerated seed-origin birch for two growing seasons. Thus, naturally regenerated birch admixture can be utilized to establish single-storied spruce-birch mixtures, and the admixture should be retained during the early cleaning of planted spruce stands.
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Männistö,
Natural Resources Institute Finland (Luke), Natural resources, Latokartanonkaari 9, FI-00790 Helsinki, Finland
https://orcid.org/0009-0009-0213-1972
E-mail:
lauri.mannisto@luke.fi
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Miina,
Natural Resources Institute Finland (Luke), Natural resources, Yliopistokatu 6 B, FI-80100 Joensuu, Finland
https://orcid.org/0000-0002-8639-4383
E-mail:
jari.miina@luke.fi
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Huuskonen,
Natural Resources Institute Finland (Luke), Natural resources, Latokartanonkaari 9, FI-00790 Helsinki, Finland
https://orcid.org/0000-0001-8630-3982
E-mail:
saija.huuskonen@luke.fi
Category :
Research article
article id 22027,
category
Research article
Timo Saksa,
Jari Miina,
Olli Luukkonen.
(2023).
Uprooting as a pre-commercial thinning operation in young Norway spruce stands.
Silva Fennica
vol.
57
no.
2
article id 22027.
https://doi.org/10.14214/sf.22027
Highlights:
The number of competing birches varied considerably according to the operating conditions; The main factors reducing the quality of uprooting were early operation timing, soil moisture and site fertility; With careful selection of the timing and conditions for uprooting, the quality obtained by uprooting can be improved.
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Uprooting, as a mechanical pre-commercial thinning operation (PCT), removes competitive, undesired trees with roots to prevent or reduce the need for a second PCT. The state of 66 young Norway spruce (Picea abies (L.) H. Karst.) stands was explored 3–5 years after uprooting to assess the quality of uprooting in terms of the number of competing birches (Betula spp.) and the probability of freely growing crop tree spruce (no competing trees taller than 2/3 of the crop tree’s height). In the uprooted spruce stands, the number of birches was, on average, about 3800 stems ha−1, and in every fifth stand, it was less than 2000 stems ha−1. The number of birches increased with increasing site wetness (TWI), site fertility and thickness of the humus layer. In 80% of the stands, there were at least 1000 freely growing spruces ha−1, which is approximately the stem number to be left growing after first thinning in a spruce stand. If the height of crop tree spruces was 125 cm at uprooting, the probability of freely growing stems varied from 0.6 to 0.8 in typical cases. According to simulations at the first thinning stage, in most stands, birch was less than 10% taller than spruce, and the volume of birches was low enough that, in the future, spruce and birch would grow in the same crown layer as a mixed spruce–birch stand. The results showed that uprooting can serve as the only PCT operation in a planted spruce stand. The quality obtained by uprooting can be improved with careful selection of timing and conditions for uprooting; the optimal uprooting time is when crop tree spruces have reached about breast height.
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Saksa,
Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, 77600 Suonenjoki, Finland
https://orcid.org/0000-0002-1776-2357
E-mail:
ext.timo.saksa@luke.fi
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Miina,
Natural Resources Institute Finland (Luke), Natural resources, Yliopistokatu 6 B, 80100 Joensuu, Finland
https://orcid.org/0000-0002-8639-4383
E-mail:
jari.miina@luke.fi
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Luukkonen,
Metsäsydän Oy, Junninmäentie 53, 52200 Puumala, Finland
E-mail:
olli.p.j.luukkonen@gmail.com
article id 10573,
category
Research article
Jari Miina,
Inka Bohlin,
Torgny Lind,
Jonas Dahlgren,
Kari Härkönen,
Tuula Packalen,
Anne Tolvanen.
(2021).
Lessons learned from assessing the cover and yield of bilberry and lingonberry using the national forest inventories in Finland and Sweden.
Silva Fennica
vol.
55
no.
5
article id 10573.
https://doi.org/10.14214/sf.10573
Highlights:
Model-based predictions of the berry yields of an average crop year are produced using the Finnish National Forest Inventory (NFI); Inventory-based estimates of seasonal berry yields are produced using the Swedish NFI observations; The inventory-based method provides seasonal estimates, whereas models can be utilised to integrate vegetation cover and berry yields in numerical multi-objective forest planning.
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Bilberry (Vaccinium myrtillus L.) and lingonberry (V. vitis-idaea L.) can be a part of healthy diet and are important for many animals. Two approaches are described to assessing their vegetation cover and berry yield via national forest inventory (NFI) observations. The aim was to provide estimates and predictions of the abundance and yield of the species at regional and national levels in Finland and Sweden. In Finland, the model-based predictions are used in evaluating the impacts of cutting intensity on forest berries needed in forest-related decision making. In Sweden, seasonal inventory-based estimates are used to evaluate the annual national and regional berry yields, and in a forecasting system aimed at large public and berry enterprises. Based on the NFI sample plots measured between 2014 and 2018, the total annual yields are estimated to be 208 Mkg of bilberry and 246 Mkg of lingonberry on productive forest land (increment at least 1 m3 ha–1 year–1) in Finland, and 336 and 382 Mkg respectively in Sweden (average of NFI inventories in 2015–2019). The predicted development of berry yields is related to the intensity of cuttings in alternative forest management scenarios: lower removals favoured bilberry, and higher removals lingonberry. The model-based method describes the effects of stand development and management on berry yields, whereas the inventory-based method can calibrate seasonal estimates through field observations. In providing spatially and timely more accurate information concerning seasonal berry yields, an assessment of berry yields should involve the elements of both inventory-based and model-based approaches described in this study.
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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
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Bohlin,
Swedish University of Agricultural sciences (SLU), Department of Forest Resource Management, Skogsmarksgränd, S-901 83 Umeå, Sweden
E-mail:
inka.bohlin@slu.se
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Lind,
Swedish University of Agricultural sciences (SLU), Department of Forest Resource Management, Skogsmarksgränd, S-901 83 Umeå, Sweden
E-mail:
torgny.lind@slu.se
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Dahlgren,
Swedish University of Agricultural sciences (SLU), Department of Forest Resource Management, Skogsmarksgränd, S-901 83 Umeå, Sweden
E-mail:
jonas.dahlgren@slu.se
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Härkönen,
Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland
E-mail:
kari.harkonen@luke.fi
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Packalen,
Natural Resources Institute Finland (Luke), Yliopistokatu 6 B, FI-80100 Joensuu, Finland; Ministry of Agriculture and Forestry of Finland, P.O. Box 30, FI-00023 Government, Finland
E-mail:
tuula.packalen@mmm.fi
-
Tolvanen,
Natural Resources Institute Finland (Luke), Paavo Havaksentie 3, FI-90014 University of Oulu, Finland
E-mail:
anne.tolvanen@luke.fi
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
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.
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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.
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Nuutinen,
Natural Resources Institute Finland (Luke), Production systems, P.O. Box 68, FI-80101 Joensuu, Finland
E-mail:
yrjo.nuutinen@luke.fi
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Miina,
Natural Resources Institute Finland (Luke), Natural resources, P.O. Box 68, FI-80101 Joensuu, Finland
E-mail:
jari.miina@luke.fi
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Saksa,
Natural Resources Institute Finland (Luke), Natural resources, FI-77600 Suonenjoki, Finland
E-mail:
timo.saksa@luke.fi
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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
article id 10196,
category
Research article
Karri Uotila,
Jari Miina,
Timo Saksa,
Ron Store,
Kauko Kärkkäinen,
Mika Härkönen.
(2020).
Low cost prediction of time consumption for pre-commercial thinning in Finland.
Silva Fennica
vol.
54
no.
1
article id 10196.
https://doi.org/10.14214/sf.10196
Highlights:
Time consumption (TC) in pre-commercial thinning (PCT) can be predicted by variables describing site and stands conditions and previous silvicultural management; Applying variables available in forest resources data the field-assessment of worksite difficulty factors is not needed; The TC model could facilitate the predictions of the labour costs of PCT in forest information systems.
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The time consumption (TC) of pre-commercial thinning (PCT) varies greatly among sites, stands and forest workers. The TC in PCT is usually estimated by field-assessed work difficulty factors. In this study, a linear mixed model for the TC in PCT was prepared by utilizing forest resources data (FRD). The modelling data included 11 848 and validation data included 3035 worksites with TC information recorded by forest workers within the period of 2008–2018. The worksites represented a range of site and stand conditions across a broad geographical area in Finland. Site and stand characteristics and previous management logically explained the TC in PCT. The more fertile the site, the more working time was needed in PCT. On sites of medium fertility, TC in the initial PCT increased with stand age by 0.5 h ha–1 yr–1. Site wetness increased the TC. PCT in summer was more time consuming than in spring. Small areas were more time consuming to PCT per hectare than larger ones. The between-forest worker variation involved in the TC was as high as 35% of the variation unexplained by the TC model. The coefficient of determination in validation data was 19.3%, RMSE 4.75 h ha–1 and bias –1.6%. The TC model based on FRD was slightly less precise than the one based on field-assessed work difficulty factors (removal quantity and type and terrain difficulty): RMSE 4.9 h ha–1 vs. 4.1 h ha–1 (52% vs. 43%). The TC model could be connected to forest information systems where it would facilitate the predictions of the labour costs of PCT without field-assessing work difficulty factors.
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Uotila,
Natural Resources Institute Finland (Luke), Natural resources, Latokartanonkaari 9, FI-00790 Helsinki, Finland
E-mail:
karri.uotila@luke.fi
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Miina,
Natural Resources Institute Finland (Luke), Natural resources, Yliopistokatu 6 B, FI-80100 Joensuu, Finland
E-mail:
jari.miina@luke.fi
-
Saksa,
Natural Resources Institute Finland (Luke), Natural resources, Survontie 9, FI-40500 Jyväskylä, Finland
E-mail:
timo.saksa@luke.fi
-
Store,
Natural Resources Institute Finland (Luke), Bioeconomy and environment, Teknologiakatu 7, FI-67100 Kokkola, Finland
E-mail:
ron.store@luke.fi
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Kärkkäinen,
E-mail:
kauko.karkkainen@gmail.com
-
Härkönen,
Tornator Oyj, Pielisentie 2–6, FI-81700 Lieksa, Finland
E-mail:
mika.harkonen@tornator.fi
article id 9933,
category
Research article
Timo Saksa,
Jari Miina,
Hilkka Haatainen,
Kauko Kärkkäinen.
(2018).
Quality of spot mounding performed by continuously advancing mounders.
Silva Fennica
vol.
52
no.
2
article id 9933.
https://doi.org/10.14214/sf.9933
Highlights:
The number and quality of mounds varied considerably according to the operating conditions;The main factors reducing the quality of spot mounding were steep terrain, a thick humus layer, fresh logging residues, stoniness and soil texture;With careful selection of timing and conditions for mounding, the quality obtained by continuously advancing mounders can be improved.
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Operating conditions affecting the quality of spot mounding by Bracke continuously advancing mounders were investigated on 66 regeneration areas (124 ha) in eastern Finland. The quality of mounds was classified as suitable (good or acceptable after additional compression) or unsuitable for planting. Models were constructed for the number of suitable planting spots obtained per hectare (good and acceptable mounds), the probability of successful mounding (≥1600 planting spots ha–1) and the probability of creating a suitable mound as a function of terrain, site and soil characteristics, as well as slash conditions (removed, fresh or dry logging residues). The average number of mounds created was 1892 ± 290 mounds ha–1, of which 1398 ± 325 mounds ha–1 (74%) were classified as suitable for planting. The quality of spot mounding was reduced by steep terrain, a thick humus layer and fresh logging residues. Stoniness and soil texture also affected the number of planting spots created. Mounding after logging residues had dried increased the number of planting spots by 191 spots ha–1 compared with mounding in the presence of fresh residues. Removing residues did not significantly increase the number of planting spots compared with mounding amongst dry residues. A thick humus layer, very stony soil, steep slopes and valley terrain decreased the number of planting spots by 150–450 spots ha–1. The number and quality of mounds varied considerably according to the operating conditions, but with careful selection of timing and sites the quality obtained by a continuously advancing mounder can be improved.
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Saksa,
Natural Resources Institute Finland (Luke), Juntintie 154, FI-77600 Suonenjoki, Finland
E-mail:
timo.saksa@luke.fi
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Miina,
Natural Resources Institute Finland (Luke), Yliopistokatu 6, FI-80100 Joensuu, Finland
E-mail:
jari.miina@luke.fi
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Haatainen,
Faculty of Science and Forestry, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland
E-mail:
hilkka.haatainen@storaenso.com
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Kärkkäinen,
Tornator Oyj, Muuntamontie 2, FI-80100 Joensuu, Finland
E-mail:
kauko.karkkainen@tornator.fi
article id 1005,
category
Research article
Marjut Turtiainen,
Jari Miina,
Kauko Salo,
Juha-Pekka Hotanen.
(2013).
Empirical prediction models for the coverage and yields of cowberry in Finland.
Silva Fennica
vol.
47
no.
3
article id 1005.
https://doi.org/10.14214/sf.1005
Highlights:
The site fertility significantly affected the abundance of cowberry on mineral soils, spruce mires and pine mires; The stand basal area and dominant tree species were among the most important forest structural predictors in the model for the coverage; In the cowberry yield model developed for mineral soil sites, the stand basal area and coverage of cowberry plants were statistically significant predictors.
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Empirical models for the coverage and berry yield of cowberry (Vaccinium vitis-idaea L.) were developed using generalized linear mixed models (GLMMs). The percentage coverage of cowberry was predicted as a function of site and stand characteristics using data from the Finnish National Forest Inventory (NFI) in 1995. The average annual yield, including the between-year variation in the yield, was predicted as a function of percentage coverage and stand characteristics using permanent experimental plots (MASI) established in different areas of Finland and measured in 2001-2012. The model for cowberry yields (Model 2) was developed for mineral soil forests. The model for the coverage (Model 1) was constructed so that it considers both mineral soil sites and also many other sites where cowberry occurs in the field layer. According to Model 1, the site fertility significantly affected the abundance of cowberry on mineral soils, spruce mires and pine mires. The stand basal area and dominant tree species were among the most important forest structural predictors in Model 1. The site fertility was not a significant predictor in the cowberry yield model. Instead, the stand basal area and coverage of cowberry plants were found to be statistically significant predictors in Model 2. The estimated models were used to predict the cowberry coverage, average annual yield and its 95 % confidence interval along with stand development. The models of this study can be used for multi-objective forest planning purposes.
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Turtiainen,
University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland
E-mail:
marjut.turtiainen@uef.fi
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Miina,
Finnish Forest Research Institute, Joensuu Unit, P.O. Box 68, FI-80101 Joensuu, Finland
E-mail:
jari.miina@metla.fi
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Salo,
Finnish Forest Research Institute, Joensuu Unit, P.O. Box 68, FI-80101 Joensuu, Finland
E-mail:
kauko.salo@metla.fi
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Hotanen,
Finnish Forest Research Institute, Joensuu Unit, P.O. Box 68, FI-80101 Joensuu, Finland
E-mail:
juha-pekka.hotanen@metla.fi
article id 181,
category
Research article
Jari Miina,
Juha-Pekka Hotanen,
Kauko Salo.
(2009).
Modelling the abundance and temporal variation in the production of bilberry (Vaccinium myrtillus L.) in Finnish mineral soil forests.
Silva Fennica
vol.
43
no.
4
article id 181.
https://doi.org/10.14214/sf.181