Swedish Forest Research Articles

Impact on species of conservation interest of forest harvesting for bioenergy purposes

Wood harvested from logging residues, pre-commercial and conservation thinnings is increasingly being used as biofuel as a substitute for fossil fuels. Here, we review the additional impact that wood harvesting for energy purposes has on species of conservation interest (SCI) in Swedish forests compared with the effects of conventional management, a perspective that largely has not been taken into consideration. We compiled data from 122 studies of forest fuel extraction with short- and long-term perspectives at the stand and landscape level to examine whether the effects on SCI are due to an additional loss of biodiversity as a result of cutting old forest or owing to competition from species that are favoured by the habitats formed by clearcutting. We also consider whether forest bioenergy extractions can be used to favour conservation values. The amount of logging residues has, in parallel to the amount of annually harvested trees, doubled during the past 50years in Sweden and constitutes the major source of dead wood for biodiversity in managed forests. Common wood-inhabiting species, predominantly fungi, beetles and other insects, and to some extent lichens, are the main species affected by wood harvesting for energy purposes. The main cause for the decline of SCI is the impact already imposed by conventional forest management: clearcutting old forest stands with subsequent soil scarification. Few SCI survive clear-felling because these species typically require other types of conditions and substrates than the new dead-wood substrate created after clear-felling. We conclude that the logging residues of conifers could potentially be harvested with small to negligible impacts on SCI. However, owing to the limited number of landscape level analyses that have been performed and the inherent difficulties of assessing the effects of wood harvesting on rare SCI, we suggest that these findings need to be treated with caution and that further studies should be undertaken. Hardwood conservation thinnings and brushwood harvest may improve conservation values. Developing operational guidelines to help to mitigate ecological damage to biodiversity should be based on cautionary principles and requires further large-scale and long-term research.

Does the harvest of logging residues and wood ash application affect the mobilization and bioavailability of trace metals?

Residue biomass from conventional forestry, such as slash (i.e., tree tops and branches) and stumps, are used at an increasing rate for energy purposes in Sweden. This review examined current knowledge on how extraction of forest biomass for large-scale energy production, including the practice of ash application for nutrient recycling, influences the mobility and stocks of trace metals in the forest environment at different time scales. The study focussed on Swedish energy production systems and contemporary forest management practices, as well as the heavy metals lead (Pb), cadmium (Cd) and mercury (Hg). The historic accumulation of these elements in forest soils has mainly originated from diffuse, long-term atmospheric deposition.There is little conclusive evidence that slash harvest generally increases the risk for mobilization of trace metals from soils during the regeneration phase, compared with stem-only harvesting. However, microbial transformation of mercury into the highly toxic methyl mercury (MeHg) species is facilitated in suboxic soil conditions that may increase during the regeneration phase. Therefore it has been hypothesized that stump harvest could result in increased mercury methylation and transport to surface waters, owing to stump harvest effects on soil physical conditions and hydrological pathways. The few studies available on the stump harvest effects of Hg showed no consistent difference in runoff from clear-felled and stump harvested catchments compared to clear-felled and soil-scarified catchments in terms of concentrations or fluxes of MeHg.Assuming that the highest trace metal concentrations in wood ash recommended by the Swedish Forest Authority are not exceeded, wood ash application does not currently increase metal loads at the national scale, because trace metal export in harvested biomass is much larger than that returned in wood ash. The net load of Pb, Cd, and Cu will not increase at the local scale if ash doses do not greatly exceed the compensation for nutrients exported in harvested biomass. Biomass harvest and ash application have negligible effects on the load of mercury to forest soils.A large number of studies have examined the effects of wood ash on trace metal content in soil, water and biota. Most studies showed no effect of wood ash application. When increased concentrations were found (Cd, Cr, Cu, Zn), this was in soils where concentrations remained well below harmful levels. Relatively fewer reports of increased concentrations are reported for soil water and plants, and no effects were reported for edible berries or fungi.

Soil-surface CO2 flux during the first 2 years after stump harvesting and site preparation in 14 Swedish forests

ABSTRACTStumps are a source of renewable energy (bioenergy) that can mitigate climate change. We aimed to determine whether conclusions from recent studies could be generalized for other sites by monitoring the in situ soil respiration (Rs) by a portable soil-respiration system of 14 clear-cut experimental sites during the first 2 years after stump extraction and site preparation. The sites were established all over Sweden in 2013 and 2014 and were subjected to no disturbance (Control), patch scarification (PatchS), disc trenching (DiscT), and stump harvesting (StumpH). During year 1, Rs from sites treated with PatchS and StumpH were 11% and 13% lower than Rs from Control sites. DiscT-treated sites were apt to produce lower Rs than the Control (−9%, p = .09). In the second year, there were no significant differences in Rs between treatments, as no soil disturbance type occurring after stump harvest and site preparation had higher Rs than untreated, intact soil. Our results suggest that soil disturbances resulting from stump harvest and site preparation do not generally increase Rs and thus, from this perspective, provide support for the use of stumps for bioenergy.

The potential role of forest management in Swedish scenarios towards climate neutrality by mid century

Swedish climate policy targets net zero greenhouse gases (GHG) by mid-century, with road transport independent of fossil fuels by 2030, requiring far-reaching changes in the way energy is used. Forest management is expected to support carbon sequestration and provide biomass for various uses, including energy. In this paper, we combine two energy scenarios with four forest scenarios and quantify GHG balances associated with energy-use for heat, electricity, and road transport, and with forest management and production, use, and end-of-life management of various forest products, including products for export. The aggregated GHG balances are evaluated in relation to the 2-degree target and an allocated Swedish CO2 budget. The production of biofuels in the agriculture sector is considered but not analyzed in detail.The results suggest that Swedish forestry can make an important contribution by supplying forest fuels and other products while maintaining or enhancing carbon storage in vegetation, soils, and forest products. The GHG neutrality goal is not met in any of the scenarios without factoring in carbon sequestration. Measures to enhance forest productivity can increase output of forest products (including biofuels for export) and also enhance carbon sequestration. The Swedish forest sector can let Sweden reach net negative emissions, and avoid “using up” its allocated CO2 budget, thereby increasing the associated emissions space for the rest of the world.

Underestimation of boreal soil carbon stocks by mathematical soil carbon models linked to soil nutrient status

Abstract. Inaccurate estimate of the largest terrestrial carbon pool, soil organic carbon (SOC) stock, is the major source of uncertainty in simulating feedback of climate warming on ecosystem–atmosphere carbon dioxide exchange by process-based ecosystem and soil carbon models. Although the models need to simplify complex environmental processes of soil carbon sequestration, in a large mosaic of environments a missing key driver could lead to a modeling bias in predictions of SOC stock change.We aimed to evaluate SOC stock estimates of process-based models (Yasso07, Q, and CENTURY soil sub-model v4) against a massive Swedish forest soil inventory data set (3230 samples) organized by a recursive partitioning method into distinct soil groups with underlying SOC stock development linked to physicochemical conditions.For two-thirds of measurements all models predicted accurate SOC stock levels regardless of the detail of input data, e.g., whether they ignored or included soil properties. However, in fertile sites with high N deposition, high cation exchange capacity, or moderately increased soil water content, Yasso07 and Q models underestimated SOC stocks. In comparison to Yasso07 and Q, accounting for the site-specific soil characteristics (e. g. clay content and topsoil mineral N) by CENTURY improved SOC stock estimates for sites with high clay content, but not for sites with high N deposition.Our analysis suggested that the soils with poorly predicted SOC stocks, as characterized by the high nutrient status and well-sorted parent material, indeed have had other predominant drivers of SOC stabilization lacking in the models, presumably the mycorrhizal organic uptake and organo-mineral stabilization processes. Our results imply that the role of soil nutrient status as regulator of organic matter mineralization has to be re-evaluated, since correct SOC stocks are decisive for predicting future SOC change and soil CO2 efflux.

Insurance models and climate risk assessments in a historical context

Adaptation to the consequences of climate change has developed into a growing field of concern for the insurance business. However, climate-related risk is not entirely a new field in insurance. Historically, a large number of insurance organisational choices and strategies have been used to mitigate the financial impact of extreme events and uncertainties associated with climate change. Taking the case of forests in Sweden, this article reviews the ways in which climate-related risks such as storm/wind and fire risks have been assured. The study shows that climate-related risks have generally increased over time and that major hazard events have been decisive for strategy and organisation choices. Twentieth-century developments show that corporate insurance coverage increased due to higher levels of anticipated risk, while self-insurance and public insurance were reduced. However, in more recent times the expansion of corporate insurance has stagnated. Increased premiums and tighter terms following historically extreme weather events have led government and forest owners to assume more climate risks.

Detailed scheduling of harvest teams and robust use of harvest and transportation resources

ABSTRACTPlanning activities of harvest teams (harvesting and forwarding) and transportation is critical for efficient procurement of roundwood from forests to mills. The planning process involves many integrated decisions that consider process, spatial and temporal aspects. The spatial aspect concerns which area to harvest, which machine team to use, the mill to which the timber should be allocated and where to store the timber. The process decisions involve which bucking instruction to use. The temporal aspect concerns when to harvest, when to transport in order to meet specific demand at mills, and when to store the timber. Temporal decisions also include determining a detailed schedule for each harvest team. Such a schedule includes starting time and movement time between harvest areas. This is complicated by the harvest team having different home bases and different machine systems with their specific performance description and capacities. The overall planning problem can be formulated into one optimization model, but such a model is too large for practical use and cannot be solved in a reasonable time. We propose a decomposition scheme where a sequence of aggregated models, or limited parts of the model, is solved to find high-quality solutions quickly. We test the scheduling in cases involving two large Swedish forest companies.

Absent neighbours and passive shareholders – The issue of residency and involvement in the management of a forest common

The Swedish forest commons can be regarded as self-organized community groups which jointly manage a forest resource. However, previous studies point out the diminishing role and engagement of shareholders in terms of governance, thereby challenging some vital design principles of robust common-pool resource institutions. We assume that major reasons for this is associated with socio-demographic changes meaning a large proportion of shareholders do not live in the area. Therefore this study compares resident and non-resident shareholder participation in and perceptions about their common, as well as assesses their engagement in the management of one major forest common in Northern Sweden. To this end a questionnaire survey was conducted together with regular consultations with the common's board and staff to discuss shareholder participation and other major issues concerning the common.The study shows that the common has a low shareholder engagement and a high proportion of non-resident shareholders. Even though a large proportion of resident shareholders acknowledged benefits from the common, they were also less satisfied with the cooperation among shareholders and less optimistic about the possibilities to influence management decisions. In contrast, the majority of non-resident shareholders saw ‘no disadvantages’ of the common. Although most of the shareholders regularly visit the common, hardly any participate in the general meetings. While residency outside the municipality certainly seems to have an impact on the engagement of non-resident shareholders, our study suggests that simple strategies from the board including accessible information and better timing and/or location of meetings might even increase the participation among all shareholders.

Adaptation and Evaluation of an Optical Flow Method Applied to Coregistration of Forest Remote Sensing Images

The coregistration of heterogeneous geospatial images is useful in various remote sensing applications. Since the number of available data increases and the resolution improves, it is interesting to have an approach as automated, fast, robust, and accurate as possible. In this paper, we present a solution based on optical-flow computation. This algorithm called GeFolki allows the registration of images in a nonparametric and dense way. GeFolki is based on a local method of optical flow derived from the Lucas–Kanade algorithm, with a multiscale implementation, and a specific filtering including rank filtering, rolling guidance filtering and local contrast inversion. The efficiency of our coregistration chain is shown on radar, LIDAR, and optical images on Remningstorp forest in Sweden. An analysis of the relevant parameters is investigated for several scenarios. Finally, we demonstrate the accuracy of our coregistration by proposing specific metrics for LIDAR/radar coregistration, and optics/radar coregistration.

Are forest researchers only scientists? Case studies on the roles of researchers in Japanese and Swedish forest policy processes

The aim of this study is to clarify the roles of researchers in forest policy development processes. Comparative case studies between Japan and Sweden were conducted. The research–integration–utilisation (RIU) model on scientific knowledge transfer was employed as a framework. Based on the RIU model, ‘scientist’, ‘integrator’, and ‘policy entrepreneur’ were defined as three hypothesised roles of researchers, discussed in conjunction with Pielke's ‘honest broker’ model. It was found that researchers played important roles, both as scientists and integrators in Japan. In Sweden, researchers played only the role of scientist. However, no researchers working as policy entrepreneurs were found in either country. These results indicate that the RIU model could work as a basis for the comparison between countries and the clarification of the roles of researchers in forest policy processes. The case study analysis also specified three additional topics for further discussion: (1) different types of science-based policy advice; (2) the relationship between power allies and consensus building; and (3) the reason why the roles of researchers differ between Japan and Sweden.

Dead wood availability in managed Swedish forests – Policy outcomes and implications for biodiversity

Dead wood is a critical resource for forest biodiversity and widely used as an indicator for sustainable forest management. Based on data from the Swedish National Forest Inventory we provide baseline information and analyze trends in volume and distribution of dead wood in Swedish managed forests during 15years. The data are based on ≈30,000 sample plots inventoried during three periods (1994–1998; 2003–2007 and 2008–2012). The forest policy has since 1994 emphasized the need to increase the amount of dead wood in Swedish forests. The average volume of dead wood in Sweden has increased by 25% (from 6.1 to 7.6m3ha−1) since the mid-1990s, but patterns differed among regions and tree species. The volume of conifer dead wood (mainly from Picea abies) has increased in the southern part of the country, but remained stable or decreased in the northern part. Heterogeneity of dead wood types was low in terms of species, diameter and decay classes, potentially negatively impacting on biodiversity. Overall, we found only minor effects of the current forest policy since most of the increase can be attributed to storm events creating a pulse of hard dead wood. Therefore, the implementation of established policy instruments (e.g. legislation and voluntary certification schemes) need to be revisited. In addition to the retention of dead trees during forestry operations, policy makers should consider calling for more large-scale targeted creation of dead trees and management methods with longer rotation cycles.

A Complexity Framework for Studying Disaster Response Management

Guided by complexity theory, in this article, we argue that a complex understanding of disaster response management can be achieved by making multiple, transparent and modest interpretations. We suggest an analytical framework in which multiple system interpretations are constructed, all based on explicit analytical choices according to three aspects: (1) system dimension, (2) system scope and (3) system resolution. We apply the framework to a major Swedish forest fire and conclude that direction and coordination as system properties, emerging at a macro level, are the result of interplay between various patterns of influences. These patterns, we argue, can be constructed and analysed through a complexity framework allowing for the construction, and contrasting, of multiple system interpretations.

Trait variations of ground flora species disentangle the effects of global change and altered land-use in Swedish forests during 20years.

Northern forest ecosystems are exposed to a range of anthropogenic processes including global warming, atmospheric deposition, and changing land-use. The vegetation of northern forests is composed of species with several functional traits related to these processes, whose effects may be difficult to disentangle. Here, we combined analyses of spatio-temporal dynamics and functional traits of ground flora species, including morphological characteristics, responses to macro- and microclimate, soil conditions, and disturbance. Based on data from the Swedish National Forest Inventory, we compared changes in occurrence of a large number of ground flora species during a 20-year period (1994-2013) in boreal and temperate Sweden respectively. Our results show that a majority of the common ground flora species have changed their overall frequency. Comparisons of functional traits between increasing and declining species, and of trends in mean trait values of sample plots, indicate that current floristic changes are caused by combined effects of climate warming, nitrogen deposition and changing land-use. Changes and their relations with plant traits were generally larger in temperate southern Sweden. Nutrient-demanding species with mesotrophic morphology were favored by ongoing eutrophication due to nitrogen deposition in the temperate zone, while dwarf shrubs with low demands on nitrogen decreased in frequency. An increase of species with less northern and less eastern distribution limits was also restricted to temperate Sweden, and indicates effects of a moister and milder macroclimate. A trend toward dense plantation forests is mirrored by a decrease of light-demanding species in both vegetation zones, and a decrease of grassland species in the temperate zone. Although denser tree canopies may buffer effects of a warmer climate and of nitrogen deposition to some extent, traits related to these processes were weakly correlated in the group of species with changing frequency. Hence, our results indicate specific effects of these often confounded anthropogenic processes.

Components and Drivers of Long-term Risk Communication: Exploring the Within-Communicator, Relational, and Content Dimensions in the Swedish Forest Context

Risk communication is important for a sustainable management of natural resources. Even though risk management is ideally ongoing, studies of long-term risk communication from the perspective of the communicator are lacking. This case study examined the preparation and implementation of forest risk communication in Sweden. Interviews were conducted with advisors at the Swedish Forest Agency, responsible for providing information to forest owners and professional foresters dealing with risks damaging the forest (e.g., storms and forest management damaging ecological values). The communicator’s perspective was analyzed based on a conceptual framework describing risk communication by means of the components: within-communicator, relational, and content. Potential drivers of the preparation and implementation of risk communication in this context, intersecting the three components, included the policy and regulatory framework, the management of the agency, the location of the agency, and the balancing of different interests.

Integrated supply of stemwood and residual biomass to forest-based biorefineries

ABSTRACTThe demand for forest biomass as raw material for a wide range of products in the developing bioeconomy is expected to increase. Along with a constant pressure on forestry to increase its productivity, this development has led to the search for new procurement methods and new assortments. The present study assessed innovative supply chain practices, with a particular focus on the integrated supply of stemwood and residual tree parts. The assortments considered included tree sections, long tops, saw logs with stump cores and small whole trees from thinnings. The assessment included geographically explicit modelling of the supply chain operations and estimation of supply cost and energy use for three industrial locations in Northern Sweden. The innovative supply chains were compared to conventional, separate, harvest of stemwood and logging residues. We conclude that integrated harvest of tops and branches with stemwood assortments, as well as whole-tree harvest in early thinnings, has a significant potential to reduce the supply cost for the non-stemwood assortments. Stump wood generally remains the most expensive assortment. The energy use analysis confirms earlier research showing that the energy input is relatively small compared to the energy content of the harvested feedstock.ABBREVIATIONSBWT, bundled whole trees; CTL, cut-to-length; ET, energy thinning; FF, final felling; FT, first thinning; LR, logging residues; LT long tops; ORN, Örnsköldsvik; PCT, pre-commercial thinning; PL, pulpwood; RS, roughly delimbed tree sections; SEK, Swedish currency; SFA, Swedish Forest Agency; SL, sawlogs; SNFI, Swedish National Forest Inventory; SP, stumps; SPC stump core; ST, second thinning; STO, Storuman; UME Umeå; WT, whole small trees;

Habitat specificity of selected grassland fungi in Norway

132 taxa of fungi regularly found in seminatural grasslands from the genera Camarophyllopsis, Clavaria, Clavulinopsis, Dermoloma, Entoloma, Geoglossum, Hygrocybe, Microglossum, Porpoloma, Ramariopsis and Trichoglossum were selected. Their habitat specificity was investigated based on 39818 records from Norway. Approximately 80% of the records were from seminatural grasslands, ca. 10% from other open habitats like parks, gardens and road verges, rich fens, coastal heaths, open rocks with shallow soil, waterfall meadows, scree meadows and alpine habitats, while 13% were found in different forest types (some records had more than one habitat type, the sum therefore exceeds 100%). Of all records in forests, at least 85% were from rich types (both deciduous and coniferous forests), while relatively few were from poor forests. Differences in habitat specificity between the taxa were analyzed. 70 taxa (53%) had less than 10% of their records in forests, while 23 (17%) had more than 20% of their records in forests. The taxa which had the highest frequency in forests in Norway are mostly the same as the most common species in forests in Sweden.

Ecosystem services in Swedish forests

ABSTRACTWe identify, describe qualitatively, quantify biophysically and, if possible, monetarily valuate the most important ecosystem services in Swedish forests. Existing Swedish and Nordic research and statistics within this area are reviewed and used to develop a first framework for the valuation of ecosystem services in Swedish forests. We base our analysis on the CICES framework and the Cascade-model. Despite the rather long occurrence and use of the concept of ecosystem services, we do not yet have enough information on the status and economic value of services in Swedish forests. The value of the forest ecosystem services is at best an indication of the different multifunctional objectives that should be met in the management of the Swedish forests. The five most central ecosystem services in Swedish forests according to annual flow are timber and pulpwood, bioenergy, game, climate regulation and recreation and training, each estimated to have a monetary value of several billion SEK. The different ecosystem services in multipurpose forests interact with each other and may lead to conflicts between use and conservation. We identified a number of trade-offs and synergies between services focusing on the five above ecosystem services.

How are Swedish Forest Owners’ Associations Adapting to the Needs of Current and Future Members and Their Organizations?

This paper examines how Swedish forest owners’ associations are adapting their strategies to fit the changing needs of current and future members, and assesses how this development affects the organizations’ profile and relationship with members. To explore this issue eight semi-structured, face-to-face interviews with chairmen and senior managers from three associations and the Federation of Swedish Family Forest Owners were performed. Results showed that associations have identified an increasing need for management-support activities among members due to their decreasing familiarity with the basics of forestry. Help is increasingly needed both for setting up goals and objectives for their forest ownership, and to practically manage their properties. The associations’ education programmes are also being improved and adapted to suit members’ varying understanding of forestry by the introduction of A-, B- and C-level courses. Education campaigns have proved to be a successful tool for affecting members’ management objectives. Further, the associations see an increasing need for political activity to counter calls for stricter management regulations being made by the media, politicians and environmental organizations and thereby protect members’ ownership rights. Initiatives within the organizations for more efficient governance processes and the professionalization of working procedures within the member organizations may, however, come to reduce individual member involvement in the associations. Members may thus increasingly come to act as customers of service in their interaction with the organizations.

Forest social values in a Swedish rural context: The private forest owners' perspective

The sustainability paradigm of the European Landscape Convention calls for increased involvement of all affected parties in combination with active leadership to promote social values. As a result, the Swedish Forest Agency (SFA) has requested further development of methods for broad consultation and active participation in order to strengthen the social values of forests. This paper aims to identify in particular the private forest owners' perceived need for collaboration and dialog regarding the social values of forests. The study's primary empirical data was derived from interviews with 40 private forest owners. A framework developed by Emerson et al. (2012) was applied to facilitate analysis of the forest owners' perceptions of procedural and institutional arrangements, existing leadership, the current level of knowledge and access to different types of resources. The paper identifies a need for the SFA to become more proactive and assume more of a leading role. The level of knowledge regarding social values was found to be quite low among the majority of the private forest owners. They wanted more information; they asked for increased support and advice, and they wanted to see improved coordination rather than collaboration on social values.

Climate risks and forest practices: forest owners' acceptance of advice concerning climate change

ABSTRACTBased on qualitative interviews with Swedish forest owners this study focuses on climate change, risk management and forest governance from the perspective of the forest owners. The Swedish forest governance system has undergone extensive deregulation, with the result that social norms and knowledge dissemination are seen by the state as important means of influencing forest owners' understandings and practices. Drawing on Foucault's concept of governmentality this study contributes knowledge on how forest owners understand and manage climate-related risk and their acceptance of advice. From the interview study, three main conclusions can be drawn: (1) forest owners' considerations largely concern ordinary forestry activities; (2) knowledge about forest management and climate adaptation combines experiences and ideas from various sources; and (3) risk awareness and knowledge of “best practices” are not enough to ensure change in forestry practices. The results of this study show that the forest owners have to be selective and negotiate about what knowledge to consider relevant and meaningful for their own forest practice. Accordingly, local forest management can be understood as situated in a web of multifarious interests, claims, concerns and knowledges, where climate change adaptation is but one of several aspects that forest owners have to consider.