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Articles by Bengt Gunnar Jonsson

Category : Research article

article id 954, category Research article

Anna-Maria Eriksson, Jörgen Olsson, Bengt Gunnar Jonsson, Sara Toivanen, Mattias Edman. (2013). Effects of restoration fire on dead wood heterogeneity and availability in three Pinus sylvestris forests in Sweden. Silva Fennica vol. 47 no. 2 article id 954. https://doi.org/10.14214/sf.954

Keywords: Scots pine; CWD; prescribed burning; decay stage; charred wood

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Restoration fires are increasingly used as a conservation tool in Sweden to recreate forests with characteristics of previous forests that were periodically disturbed by fires and promote fire-dependent species. Restoration fires can result in large inputs of fresh dead wood, but there are risks of losing some of the existing, pre-fire dead wood. To assess these counteracting effects we studied the heterogeneity and availability of dead wood before and after three restoration fires in boreal Scots pine forests. Specifically, we studied volumes of stumps, high stumps, snags and logs. The fires decreased the total volume of pre-fire dead wood (23-41%) and consumed logs in late decay stages (26-54%) to a higher extent than logs in earlier stages. The input of new fresh dead wood after the fires exceeded losses of pre-fire dead wood and resulted in a net increase of dead wood in all three sites. The added dead wood consisted of fresh snags killed by the fires. Fire also affected log characteristics: reducing their vegetation coverage (60-98%), decreasing their ground contact (4-50%) and increasing their surface area of charred wood (>50%). Such changes have important consequences for the micro environmental conditions inside logs, but have been rarely studied in relation to restoration fires. Our results show that restoration fire causes changes in dead wood availability and characteristics of logs. The results imply that ideally stands with low abundance of rare and heavily decayed wood substrates should be burned to optimize dead wood values. Alternatively, management practices should include protection of these substrates during restoration fires.

Eriksson, Department of Natural Sciences, Mid Sweden University, SE-851 70, Sundsvall, Sweden E-mail: anna-maria.eriksson@miun.se
Olsson, Department of Ecology and Environmental Science, Umeå University, SE-901 87, Umeå, Sweden E-mail: jorgen.m.olsson@slu.se
Jonsson, Department of Natural Sciences, Mid Sweden University, SE-851 70, Sundsvall, Sweden E-mail: bengt-gunnar.jonsson@miun.se
Toivanen, Department of Natural Sciences, Mid Sweden University, SE-851 70, Sundsvall, Sweden E-mail: sara.toivanen@lansstyrelsen.se
Edman, Department of Natural Sciences, Mid Sweden University, SE-851 70, Sundsvall, Sweden E-mail: mattias.edman@miun.se

article id 90, category Research article

Per Angelstam, Kjell Andersson, Robert Axelsson, Marine Elbakidze, Bengt Gunnar Jonsson, Jean-Michel Roberge. (2011). Protecting forest areas for biodiversity in Sweden 1991–2010: the policy implementation process and outcomes on the ground. Silva Fennica vol. 45 no. 5 article id 90. https://doi.org/10.14214/sf.90

Keywords: forest policy; forest protection; restoration ecology; connectivity; green infrastructure; umbrella species; forest disturbance regimes; participation and collaboration

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Swedish forest and environmental policies imply that forests should be managed so that all naturally occurring species are maintained in viable populations. This requires maintenance of functional networks of representative natural forest and cultural woodland habitats. We first review the policy implementation process regarding protected areas in Sweden 1991–2010, how ecological knowledge was used to formulate interim short-term and strategic long-term biodiversity conservation goals, and the development of a hierarchical spatial planning approach. Second, we present data about the amount of formally protected and voluntarily set aside forest stands, and evaluate how much remains in terms of additional forest protection, conservation management and habitat restoration to achieve forest and environmental policy objectives in the long-term. Third, a case study in central Sweden was made to estimate the functionality of old Scots pine, Norway spruce and deciduous forest habitats, as well as cultural woodland, in different forest regions. Finally, we assess operational biodiversity conservation planning processes. We conclude that Swedish policy pronouncements capture the contemporary knowledge about biodiversity and conservation planning well. However, the existing area of protected and set-aside forests is presently too small and with too poor connectivity. To bridge this gap, spatial planning, management and restoration of habitat, as well as collaboration among forest and conservation planners need to be improved.

Angelstam, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Skinnskatteberg, Sweden E-mail: per.angelstam@slu.se
Andersson, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Skinnskatteberg, Sweden E-mail: ka@nn.se
Axelsson, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Skinnskatteberg, Sweden E-mail: ra@nn.se
Elbakidze, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Skinnskatteberg, Sweden E-mail: me@nn.se
Jonsson, Dept of Natural Science, Engineering and Mathematics, Mid Sweden University, Sundsvall, Sweden E-mail: bgj@nn.se
Roberge, Dept of Wildlife, Fish and Environmental Studies, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Umeå, Sweden E-mail: jmr@nn.se

article id 80, category Research article

Mari T. Jönsson, Shawn Fraver, Bengt Gunnar Jonsson. (2011). Spatio-temporal variation of coarse woody debris input in woodland key habitats in central Sweden. Silva Fennica vol. 45 no. 5 article id 80. https://doi.org/10.14214/sf.80

Keywords: boreal forest; Picea abies; dendrochronology; disturbance dynamics; tree mortality; woodland key habitats; windstorms

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The persistence of many saproxylic (wood-living) species depends on a readily available supply of coarse woody debris (CWD). Most studies of CWD inputs address stand-level patterns, despite the fact that many saproxylic species depend on landscape-level supplies of CWD. In the present study we used dated CWD inputs (tree mortality events) at each of 14 Norway spruce (Picea abies) dominated woodland key habitat sites to analyze the spatial and temporal patterns of CWD additions between 1950 and 2002 within a small landscape in central Sweden. We found that inputs were episodic within sites, where local windstorms created pulses in CWD input. Pulses occurred simultaneously in many sites, yielding landscape-level synchrony of CWD input. These synchronous pulses, and importantly, the breaks between pulses, may have negative implications for saproxylic species that are dependent on large volume inputs of freshly killed Norway spruce. In addition, the inherent small size and relative isolation of these sites may further increase extinction risks due to stochastic events. However, background CWD input rates occurring between pulses varied substantially among sites, presumably the result of the sites’ varied histories and structural characteristics. This finding suggests that the different sites have varied abilities to provide habitat for saproxylic species during periods with low landscape-level input of CWD.

Jönsson, Department of Ecology, SLU, P.O. Box 7044, SE-750 07 Uppsala, Sweden (current); Department of Natural Sciences, Engineering and Mathematics, Mid Sweden University, Sundsvall, Sweden E-mail: mari.jonsson@slu.se
Fraver, U.S. Forest Service, Northern Research Station, Grand Rapids, Minnesota, USA (current); Department of Natural Sciences, Engineering and Mathematics, Mid Sweden University, Sundsvall, Sweden E-mail: sf@nn.us
Jonsson, Department of Natural Sciences, Engineering and Mathematics, Mid Sweden University, Sundsvall, Sweden E-mail: bgj@nn.se

Category : Review article

article id 446, category Review article

Guntis Brumelis, Bengt Gunnar Jonsson, Jari Kouki, Timo Kuuluvainen, Ekaterina Shorohova. (2011). Forest naturalness in northern Europe: perspectives on processes, structures and species diversity. Silva Fennica vol. 45 no. 5 article id 446. https://doi.org/10.14214/sf.446

Keywords: disturbances; dead wood; natural forest; biological diversity

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Saving the remaining natural forests in northern Europe has been one of the main goals to halt the ongoing decline of forest biodiversity. To facilitate the recognition, mapping and efficient conservation of natural forests, there is an urgent need for a general formulation, based on ecological patterns and processes, of the concept of “forest naturalness”. However, complexity, structural idiosyncracy and dynamical features of unmanaged forest ecosystems at various spatio-temporal scales pose major challenges for such a formulation. The definitions hitherto used for the concept of forest naturalness can be fruitfully grouped into three dimensions: 1) structure-based concepts of natural forest, 2) species-based concepts of natural forest and 3) process-based concepts of natural forest. We propose that explicit and simultaneous consideration of all these three dimensions of naturalness can better cope with the natural variability of forest states and also aid in developing strategies for forest conservation and management in different situations. To become operational, criteria and indicators of forest naturalness need to integrate the three dimensions by combining species (e.g. red-listed-, indicator- and umbrella species) with stand and landscape level structural features that are indicative of disturbance and succession processes.

Brumelis, Faculty of Biology, University of Latvia, Kronvalda bulv. 4, Riga, LV-1586, Latvia; E-mail: guntis.brumelis@lu.lv
Jonsson, Department of Natural Sciences, Engineering and Mathematics, Mid Sweden University, Sundsvall, Sweden E-mail: bgj@nn.se
Kouki, School of Forest Sciences, University of Eastern Finland, Joensuu, Joensuu E-mail: jk@nn.fi
Kuuluvainen, Department of Forest Sciences, University of Helsinki, Finland E-mail: tk@nn.fi
Shorohova, Saint-Petersburg State Forest Academy, Saint-Petersburg, Russia & Finnish Forest Research Institute, Vantaa Research Unit, Vantaa, Finland E-mail: es@nn.ru

article id 390, category Review article

Bengt Gunnar Jonsson, Nicholas Kruys, Thomas Ranius. (2005). Ecology of species living on dead wood – lessons for dead wood management. Silva Fennica vol. 39 no. 2 article id 390. https://doi.org/10.14214/sf.390

Keywords: forest management; saproxylic species; coarse woody debris; woodland key habitats; landscape planning; Fennoscandian forests; epixylic species

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Dead wood has been identified as a crucial component for forest biodiversity. Recent research has improved our understanding of habitat relations for many species associated with dead wood. However, the consequences for forest management are yet to be explored. In this review we build upon the growing volume of studies on dead wood dependent species, the dynamics of dead wood and ecological theory in order to identify the challenges for forest management at the landscape level. The review has a Fennoscandian focus, but the problems and challenges are similar in many forest ecosystems. We argue that it is necessary to 1) counteract the current shortage in availability of dead wood, 2) concentrate planning at the landscape level in order to minimize isolation and reduce edge effects, 3) create a variety of dead wood types, and 4) utilise available quantitative analytical tools. This calls for new approaches to management that to a large extent includes available knowledge, and to find platforms for planning forested landscapes with diverse holdings.

Jonsson, Mid Sweden University, Dept of Natural Sciences, SE-851 70 Sundsvall, Sweden E-mail: bengt-gunnar.jonsson@miun.se
Kruys, SLU, Dept of Forest Resource Management and Geomatics, SE-901 83 Umeå, Sweden E-mail: nk@nn.se
Ranius, SLU, Dept of Entomology, SE-750 07 Uppsala, Sweden E-mail: tr@nn.se

Category : Commentary

article id 445, category Commentary

Bengt Gunnar Jonsson, Jari Kouki, Timo Kuuluvainen. (2011). Northern Primeval Forests – Ecology, Conservation and Management. Silva Fennica vol. 45 no. 5 article id 445. https://doi.org/10.14214/sf.445

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Jonsson, Mid Sweden University, Dept. of Natural Sciences, Sundsvall, Sweden E-mail: bengt-gunnar.jonsson@miun.se
Kouki, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland E-mail: jari.kouki@uef.fi
Kuuluvainen, University of Helsinki, Dept. of Forest Science, Helsinki, Finland E-mail: timo.kuuluvainen@helsinki.fi

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