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Category: Review article

article id 1095, category Review article, 19737 views

Jonas Fridman, Sören Holm, Mats Nilsson, Per Nilsson, Anna Hedström Ringvall & Göran Ståhl. (2014). Adapting National Forest Inventories to changing requirements – the case of the Swedish National Forest Inventory at the turn of the 20th century. Silva Fennica vol. 48 no. 3 article id 1095. https://doi.org/10.14214/sf.1095

Keywords: sample plot inventory; forest state; ENFIN; harmonization; sampling; remote sensing

Highlights: National Forest Inventories supply invaluable long term time series of forest state. Recent developments and international harmonization of modern NFIs widen the scope to even include ecosystem goods, e.g. biodiversity and carbon sequestration. The combination of NFI field data with remote sensing techniques can give good estimates for areas smaller than national and regional level.

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National Forest Inventories (NFIs) are becoming increasingly important worldwide in order to provide information about the multiple functions of forests, e.g. their provision of raw materials to industry, biodiversity and their capacity to store carbon for mitigating climate change. In several countries the history of NFIs is very long. For these countries a specific challenge is to keep the inventories up-to-date without sacrificing the advantages associated with long time series. At the turn of the 20th century European NFIs faced some major challenges. In this article we describe the history and the recent developments of the Swedish NFI as an example from which general observations are made and discussed. The Swedish NFI started in 1923 and has evolved from an inventory with a narrow focus on wood resources to an inventory today which aims to provide information about all major forest ecosystem services. It can be concluded that the traditional approaches of most European NFIs, e.g. to collect data through sample plot field inventories, has proved to be applicable even for a wide range of new information requirements. Specifically, detailed data about land use, trees, vegetation, and soils has found new important uses in connection with biodiversity assessments and the estimation of greenhouse gas emissions. Though time-consuming and difficult, making NFI information comparable across countries through harmonization appears to be a useful approach. The European National Forest Inventory Network (ENFIN) was formed in 2003 and has been successful in pan-European NFI harmonization.

Fridman, Swedish University of Agricultural Sciences (SLU), SE-901 83 Umeå, Sweden ORCID ID: – E-mail: jonas.fridman@slu.se
Holm, Swedish University of Agricultural Sciences (SLU), SE-901 83 Umeå, Sweden ORCID ID: – E-mail: soren.holm@slu.se
Nilsson, Swedish University of Agricultural Sciences (SLU), SE-901 83 Umeå, Sweden ORCID ID: – E-mail: mats.nilsson@slu.se
Nilsson, Swedish University of Agricultural Sciences (SLU), SE-901 83 Umeå, Sweden ORCID ID: – E-mail: per.nilsson@slu.se
Ringvall, Swedish University of Agricultural Sciences (SLU), SE-901 83 Umeå, Sweden ORCID ID: – E-mail: Anna.Ringvall@slu.se
Ståhl, Swedish University of Agricultural Sciences (SLU), SE-901 83 Umeå, Sweden ORCID ID: – E-mail: goran.stahl@slu.se

article id 1660, category Review article, 7363 views

Lars Rytter, Morten Ingerslev, Antti Kilpeläinen, Piritta Torssonen, Dagnija Lazdina, Magnus Löf, Palle Madsen, Peeter Muiste & Lars-Göran Stener. (2016). Increased forest biomass production in the Nordic and Baltic countries – a review on current and future opportunities. Silva Fennica vol. 50 no. 5 article id 1660. https://doi.org/10.14214/sf.1660

Keywords: coppice; cultivation areas; fertilization; growth increment; nurse crops; tree breeding; tree species

Highlights: Annual growth is 287 million m³ in the forests of the Nordic and Baltic countries; Growth can be increased by new tree species, tree breeding, high-productive management systems, fertilization and afforestation of abandoned agricultural land; We predict a forest growth increment of 50–100% is possible at the stand scale; 65% of annual growth is harvested today.

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The Nordic and Baltic countries are in the frontline of replacing fossil fuel with renewables. An important question is how forest management of the productive parts of this region can support a sustainable development of our societies in reaching low or carbon neutral conditions by 2050. This may involve a 70% increased consumption of biomass and waste to meet the goals. The present review concludes that a 50–100% increase of forest growth at the stand scale, relative to today’s common level of forest productivity, is a realistic estimate within a stand rotation (~70 years). Change of tree species, including the use of non-native species, tree breeding, introduction of high-productive systems with the opportunity to use nurse crops, fertilization and afforestation are powerful elements in an implementation and utilization of the potential. The productive forests of the Nordic and Baltic countries cover in total 63 million hectares, which corresponds to an average 51% land cover. The annual growth is 287 million m³ and the annual average harvest is 189 million m³ (65% of the growth). A short-term increase of wood-based bioenergy by utilizing more of the growth is estimated to be between 236 and 416 TWh depending on legislative and operational restrictions. Balanced priorities of forest functions and management aims such as nature conservation, biodiversity, recreation, game management, ground water protection etc. all need consideration. We believe that these aims may be combined at the landscape level in ways that do not conflict with the goals of reaching higher forest productivity and biomass production.

Rytter, The Forestry Research Institute of Sweden (Skogforsk), Ekebo 2250, SE-26890 Svalöv, Sweden ORCID ID: – E-mail: lars.rytter@skogforsk.se
Ingerslev, Copenhagen University, Department of Geosciences and Natural Resource Management, Rolighedsvej 23, DK-1958, Frederiksberg C, Denmark ORCID ID: – E-mail: moi@ign.ku.dk
Kilpeläinen, Finnish Environment Institute, Joensuu Office, P.O. Box 111, FI-80101 Joensuu, Finland; University of Eastern Finland, Faculty of Science and Forestry, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID: – E-mail: antti.kilpelainen@ymparisto.fi
Torssonen, University of Eastern Finland, Faculty of Science and Forestry, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID: – E-mail: Piritta.Torssonen@uef.fi
Lazdina, Latvian State Forest Research Institute “Silava”, 111 Riga str, Salaspils, LV 2169 Latvia ORCID ID: – E-mail: Dagnija.Lazdina@silava.lv
Löf, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, Box 49 SE-230 53 Alnarp, Sweden ORCID ID: – E-mail: magnus.lof@slu.se
Madsen, Copenhagen University, Department of Geosciences and Natural Resource Management, Rolighedsvej 23, DK-1958, Frederiksberg C, Denmark ORCID ID: – E-mail: pam@ign.ku.dk
Muiste, Estonian University of Life Sciences, Institute of Forestry and Rural Engineering, Dept. Forest Industry, Kreutzwaldi 5, Tartu 51014, Estonia ORCID ID: – E-mail: Peeter.Muiste@emu.ee
Stener, The Forestry Research Institute of Sweden (Skogforsk), Ekebo 2250, SE-26890 Svalöv, Sweden ORCID ID: – E-mail: Lars-Goran.Stener@skogforsk.se

article id 1008, category Review article, 6116 views

Janusz Szmyt. (2014). Spatial statistics in ecological analysis: from indices to functions. Silva Fennica vol. 48 no. 1 article id 1008. https://doi.org/10.14214/sf.1008

Keywords: spatial analyses; spatial indices; spatial functions; spatial ecology

Highlights: Spatial statistics provides a quantitative description of natural variables distributed in space and time; The objectives of spatial analysis are to detect spatial patterns and to confirm if a pattern found is significant; Spatially explicit indices and functions may be applied depending on the information collected from the field; Development of the specific software supports spatial analyses.

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This paper presents a review of the most common methods in ecological studies aimed at spatial analysis of population structures (horizontal and vertical), based on point process statistics. Methods based on simple spatially explicit indices as well as more sophisticated methods relying on functions are described in a comprehensible manner. Simple indices revealing the information on spatial structure at the scale of the nearest neighbor can be easily implemented in practical forestry. On the other hand, spatial functions, based on much more detailed data, describe the spatial structure in terms of the spatial relationships between the natural processes and population structures and because of this complexity they are rarely used in forest practice. Including both methods in a single paper is also valuable from the potential reader’s point of view saving their time for searching and choosing the appropriate method to make their spatial analysis. This paper can also serve as an initial guide for young researchers or those who are going to start their studies on spatial aspects of bio-systems. Avoiding the statistical and mathematical details makes this paper understandable for readers who are not statisticians or mathematicians. Readers will find many references related to each method described here, allowing them to find solutions to different problems observed in practice. This paper ends with a list of the most common specific software packages available to support spatial analysis.

Szmyt, Department of Silviculture, Faculty of Forestry, Poznań University of Life Sciences, ul. Wojska Polskiego 69, 60-625 Poznań, Poland ORCID ID: – E-mail: jszmyt@up.poznan.pl

article id 1673, category Review article, 4104 views

Eshetu Yirdaw, Mulualem Tigabu & Adrian Monge. (2017). Rehabilitation of degraded dryland ecosystems – review. Silva Fennica vol. 51 no. 1B article id 1673. https://doi.org/10.14214/sf.1673

Keywords: land degradation; desertification; rangelands; croplands; dry forests; landscapes; restoration

Highlights: The prospect of restoring degraded drylands is technically promising; The forest landscape restoration concept can be used as the overarching rehabilitation framework; Development of process-based models that forecast rehabilitation outcomes is needed; Rehabilitation methodologies developed for moist areas are not necessarily suitable for drylands; More data is needed on cost-benefit analysis of rehabilitation interventions.

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Land degradation is widespread and a serious threat affecting the livelihoods of 1.5 billion people worldwide of which one sixth or 250 million people reside in drylands. Globally, it is estimated that 10–20% of drylands are already degraded and about 12 million ha are degraded each year. Driven by unsustainable land use practices, adverse climatic conditions and population increase, land degradation has led to decline in provision of ecosystem services, food insecurity, social and political instability and reduction in the ecosystem’s resilience to natural climate variability. Several global initiatives have been launched to combat land degradation, including rehabilitation of degraded drylands. This review aimed at collating the current state-of-knowledge about rehabilitation of degraded drylands. It was found that the prospect of restoring degraded drylands is technically promising using a suite of passive (e.g. area exclosure, assisted natural regeneration, rotational grazing) and active (e.g. mixed-species planting, framework species, maximum diversity, and use of nurse tree) rehabilitation measures. Advances in soil reclamation using biological, chemical and physical measures have been made. Despite technical advances, the scale of rehabilitation intervention is small and lacks holistic approach. Development of process-based models that forecast outcomes of the various rehabilitation activities will be useful tools for researchers and practitioners. The concept of forest landscape restoration approach, which operates at landscape-level, could also be adopted as the overarching framework for rehabilitation of degraded dryland ecosystems. The review identified a data gap in cost-benefit analysis of rehabilitation interventions. However, the cost of rehabilitation and sustainable management of drylands is opined to be lower than the losses that accrue from inaction, depending on the degree of degradation. Thus, local communities’ participation, incorporation of traditional ecological knowledge, clear division of tasks and benefits, strengthening local institutions are crucial not only for cost-sharing, but also for the long-term success of rehabilitation activities.

Yirdaw, Viikki Tropical Resources Institute (VITRI), Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID: – E-mail: eshetu.yirdaw@helsinki.fi
Tigabu, Sveriges Lantbruks Universitet (SLU), Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53, Alnarp, Sweden ORCID ID: – E-mail: Mulualem.Tigabu@slu.se
Monge, Viikki Tropical Resources Institute (VITRI), Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID: – E-mail: adrian.mongemonge@helsinki.fi

Category: Research article

article id 935, category Research article, 3578 views

Loice M. A. Omoro, Mike Starr & Petri K. E. Pellikka. (2013). Tree biomass and soil carbon stocks in indigenous forests in comparison to plantations of exotic species in the Taita Hills of Kenya. Silva Fennica vol. 47 no. 2 article id 935. https://doi.org/10.14214/sf.935

Keywords: biomass; carbon stocks; Eastern Arc Montane forest; exotic tree species; indigenous forest; soil carbon

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Carbon (C) densities of the tree biomass and soil (0–50 cm) in indigenous forest and plantations of eucalyptus, cypress and pine in the Taita Hills, Kenya were determined and compared. The cypress and pine plantations were about 30-years-old and eucalyptus plantations about 50-years-old. Biomass C densities were estimated from breast height diameter and wood density using allometric functions developed for tropical species and an assumed C content of 50%. Belowground biomass C densities were estimated using root:shoot biomass ratios. Soil organic C (SOC) densities were calculated from measured organic carbon contents (0–20 and 20–50 cm layers) and modelled bulk density values. Mean total biomass C and SOC densities for indigenous forest were greater than those of the plantations, and the difference was significant (p < 0.05) in the cases of cypress and pine biomass and pine SOC. The correlation between biomass C and SOC densities was nearly significant in the case of indigenous forest, but negative. Biomass C densities were not significantly correlated with mean annual precipitation, mean annual temperature or potential evapotranspiration, but pine biomass C densities were significantly correlated to actual evapotranspiration. SOC densities were more strongly correlated to mean annual precipitation than biomass C densities, but only significantly so in the case of pine. Neither biomass C nor SOC densities were correlated to plant available water capacity of the soil. Indigenous forest SOC densities were significantly correlated to soil clay contents, but negatively. Indigenous forests sequester more C in biomass and soil than do 30 to 50-year-old plantations of exotics, but it remains unclear if this is an intrinsic difference between indigenous forest and plantations of exotics or because of insufficient time for SOC levels in plantations to recover after clearance of original indigenous forest.

Omoro, Viikki Tropical Resources Institute, Department of Forest Sciences, P.O. Box 27 (Latokartanonkaari 7), FI-00014 University of Helsinki, Finland ORCID ID: – E-mail: loice.omoro@helsinki.fi
Starr, Department of Forest Sciences, P. O. Box 27 (Latokartanonkaari 7), FI-00014 University of Helsinki, Finland ORCID ID: – E-mail: mike.starr@helsinki.fi
Pellikka, Department of Geosciences and Geography, P. O. Box 64 (Gustaf Hällströminkatu 2), FI-00014 University of Helsinki, Finland ORCID ID: – E-mail: petri.pellikka@helsinki.fi

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