Swedish University of Agricultural Sciences

Our research targets the role of forests under the international Paris Climate Agreement, the EU Green Deal and Forest Strategy. In line with the latter objectives, Member States are expected to encourage forest owners to contribute to international climate goals via national strategic plans and new management measures. How forest owners will respond, however, to a range of climate smart forestry (CSF) measures in the near future, is not well known. After postal and email distribution in 2020, 98 Swedish (response rate 21%) and 241 Dutch forest owners (24%) filled out a forest-climate survey. Based upon specific CSF measures, several hypothetical climate-related scenarios were incorporated into the survey. Dutch forest owners are planning to introduce new tree species, more mixed species stands (a gradual shift to broadleaved species) and additional water reservoirs in anticipation of increased drought periods, all part of a hypothetical climate adaptation package for 2030. Swedish forest owners prefer earlier thinning and salvaging activities. Zooming in on Dutch scale differences, small forest owners rely less on current public subsidy packages and show significantly less interest in committing to the adaptation package than large forest owners. In Sweden, preferences for the high forest management intensity scenario is significantly affected by size class: more intensive activities are the least popular with the smallest forest owners. The greatest difference between both countries is the way in which CSF measures should be financially supported. In general, Dutch forest owners would prefer to maintain subsidy schemes but adapt them to new circumstances, while Swedish forest owners benefit from timber and bioenergy markets. At the end there are some suggestions for a monitoring framework for resilient European forests.

In the context of continuous cover forestry (CCF), natural regeneration is the preferred form of regeneration, but it is a long-lasting and complex process. Shelter density has a large effect on the regeneration process and results. The selection system, particularly suited for shade-tolerant species like Norway spruce, relies on continuous regeneration and ingrowth into larger size classes. Regeneration and ingrowth rates vary significantly among stands, influenced by site and historical factors, with no clear relationship to current stand conditions. In the group system, edge trees influence regeneration by providing seeds, checking weed growth, and exerting competition. Regeneration in gaps is generally satisfactory for both Norway spruce and Scots pine. However, seedlings usually grow slower, especially close to the gap edges. The shelterwood system promotes regeneration through a successive, uniform opening of the canopy. Shelter trees provide seeds, and reduce seedling damage and competition from ground vegetation. On the other hand, the remaining overstorey shelter trees reduce seedling growth. Conversion to the selection system initiates regeneration in young stands, aiming for slow and steady regeneration. Given the rapid growth and crown closure in young stands, frequent manipulation of shelter density is essential during conversion, for example by opening small gaps.

Boreal forests sequester and store large amounts of carbon both above and below ground. Forest management could influence carbon storage. Differences between upland soils and peatlands are important. In peatlands, large amounts of carbon are stored in the peat, making them more susceptible to differences in forest management. On peatlands, carbon balance is mostly determined by groundwater levels. Carbon storage on both upland and peat soils depends on harvest intensity since most carbon losses, apart from harvested forest products, come from decomposition of roots and logging residues. Scales in both space and time are both important considerations when estimating the effect on carbon balances.

Conventional forest operations can exert significant impacts on the hydrology and water quality of downstream aquatic environments. Few research results have been published on the impacts of continuous cover forestry (CCF) on water quality. CCF could be useful for reducing nutrient, carbon, and suspended solid exports in waterways. CCF may be a better alternative to rotation forestry (RF) on mineral soils and drained peatlands. Further research is needed on the many processes controlling nutrient and carbon exports in CCF and RF.

Forest planning requires unbiased and sufficient information on current forest resources, their anticipated dynamics under different management scenarios, and the objectives of the decision maker. Forest planning systems need to be adapted to improve their potential to deal with continuous cover forestry (CCF). The current forest planning systems and associated models can be adapted to group systems by treating each group as a separate calculation unit. In the selection system, currently available growth models may not realistically describe the growth reaction of trees, which causes additional uncertainty in forest-planning calculations. Furthermore, field-data collection based on airborne laser scanning alone is not sufficient for planning of CCF, and additional field measurements are needed. Tree-level measurements by drones open interesting opportunities for forest planning, which might be especially useful under CCF.

Definitions of continuous cover forestry (CCF) vary among countries, and are often a political compromise. We offer a common definition of CCF for this book, which can be found in a text box below. The three silvicultural systems included in CCF are described briefly. Conversion to CCF will be an important activity in the near future, but approaches to and experiences of conversion to CCF are largely lacking in Fennoscandia. Methods need to be developed for how to assess the suitability of forest stands for CCF or conversion to CCF. Bad practices and experiences with selective cutting in Fennoscandia before 1950 have led to a loss of experience and willingness to apply CCF. Climate adaptation will make it necessary to modify CCF approaches in the region, especially given the limited number of shade-tolerant species.

Heterobasidion root and butt rot pose a greater risk in continuous cover forestry (CCF) than in rotation forestry (RF) in conifer-dominated forests, regardless of whether selective, gap or shelterwood cutting is used. Damage from wind, snow, spruce bark beetle, and large pine weevil are likely to be less severe in CCF than in RF. However, the conversion of RF to CCF may briefly expose stands to windthrow. Browsing by large herbivores on saplings may limit regeneration of tree species other than spruce in continuous cover forestry and reduce tree species diversity, but alternative silvicultural practices may also increase forage availability in the field and shrub layer. Browsing damage outcomes for saplings in CCF are difficult to predict. For many types of damage in CCF, substantial knowledge gaps complicate the assessment of damage risk.

Hydropower dams come with high ecological and social costs, not least concerning longitudinal connectivity in rivers, which causes declines and sometimes local extinctions of fish species. Fishways are widely used to allow fish to pass dams, but their efficiency is highly variable between species and sites. Many species, and at places entire fish communities, remain understudied, likely hindering the implementation of effective remedial measures. Here, we studied fish passage behaviour in a vertical slot fishway in the Po River, Italy. Almost 1000 individual fish of nine species, representing the local fish community, were tagged and released within and downstream of the fishway. The only species passing the fishway at relatively high numbers were potamodromous barbel and Italian chub, and for these species passage success was positively related to fish size. Passage was more likely to occur at night than during the day for barbel, but not for chub. In relation to the dispersal of invasive species, it is noteworthy that a few individuals of Wels catfish and common carp passed the fishway.

Climate change requires locally tailored solutions that consider diverse environmental and cultural contexts. This study situates climate action within Sweden's forest landscapes, exploring how local forest stakeholders prioritize and motivate climate action targets for immediate implementation. By engaging in knowledge co-production processes in local communities, we sought to develop place-based climate action pathways, rooted in stakeholders' visions for their communities' futures. We identified three main climate action pathways: forest-based bioeconomy, localism, and global systemic change. These pathways varied in policy targets, governance directions, focus of change, and preferred economic systems. We found that while the pathways generally aligned with the underlying assumptions of overarching scenario archetypes, their ideological differences regarding governance and policy levels and directions were less distinct. Moreover, despite differing foci and perspectives, forest management strategies were similar in all pathways. The ideological dimensions of the climate action pathways became less visible when considering the management of forests. Our findings underscore the embeddedness of local climate action within broader environmental, social, and political structures, and the challenges of linking local landscape understandings to global environmental processes. While practical, locally specific solutions can transcend ideological debates, they may also obscure necessary ideological and political considerations for effective land use and management strategies for climate change adaptation and mitigation.

Cerebral cavernous malformation (CCM) is a neurovascular disease with symptoms such as strokes, hemorrhages and neurological deficits. With surgery being the only treatment strategy, understanding the molecular mechanisms of CCM is crucial in finding alternative therapeutic options for CCM. Neutrophil extracellular traps (NETs) were recently reported in CCM, and NETs were shown to have positive or negative effects in different disease contexts. In this study, we investigated the roles of NETs in CCM by pharmacologically inhibiting NET formation using Cl-amidine (a peptidyl arginine deiminase inhibitor). We show here that Cl-amidine treatment reduced lesion burden, coagulation and endothelial-to-mesenchymal transition. Furthermore, NETs promoted the activation of microglia and fibroblasts, leading to increased neuroinflammation and a chronic wound microenvironment in CCM. The inhibition of NET formation caused endothelial quiescence and promoted a healthier microenvironment. Our study suggests the inhibition of NETs as a potential therapeutic strategy in CCM.

High-resolution, wall-to-wall forest information enables precision-driven decision-making in forest management planning. In a case study we compare planning approaches using such information for solving long-term forest planning problems. The two first approaches are based on dynamic treatment unit (DTU) planning with high-resolution cells (12.5 × 12.5 m²) or segments (0.27 ha on average), respectively, solved with a cellular automata heuristics. The third approach is a traditional stand-based approach using stands (5.2 ha on average) and linear programming to solve the planning problem. Fixed costs associated with cutting operations are quantified as each treatment unit is charged with an entry cost of 10 000 SEK. The entry costs are included in the DTU approach while in the stand approach entry costs are applied accordingly in a post-optimization routine. In large, the analyses are based on open-access tools and data provided by Swedish authorities. The traditional stand approach produced plans with 5.2–2.7% lower net present value compared to DTU planning. Most of the differences were caused by greater suboptimal losses in plans produced with the stand approach, but entry costs were also lower in DTU plans. While forestry was less profitable, treatment units were more spatially compact with stands, especially compared to cell-based plans. Therefore, we reason that a combination of modelling of direct costs and use of spatial proxy variables, such as common border length, may be advisable in DTU planning to achieve compact and realistic treatment units. Finally, the results indicate that high-resolution data and DTU planning may better utilize forests’ potential of economic production, compared to the traditional stand approach.

Triana and Andreazza et al. describe nootkatone, a grapefruit volatile, as a potent mosquito repellent and an insecticide. Nootkatone induces spatial and contact repellency, preventing feeding, and potentiates GABA-mediated inhibition, causing paralysis. Its safety for humans and pleasant scent makes nootkatone a promising option for mosquito control.

Insect–plant interactions are key determinants of plant and insect fitness, providing important ecosystem services around the world—including the Arctic region. Recently, it has been suggested that climate warming causes rifts between flower and pollinator phenology. To what extent the progression of pollinators matches the availability of flowers in the Arctic season is poorly known. In this study, we aimed to characterize the community phenology of flowers and insects in a rapidly changing Arctic environment from a descriptive and functional perspective. To this end, we inferred changes in resource availability from both a plant and an insect point of view, by connecting resource and consumer species through a metaweb of all the plant–insect interactions ever observed at a site. Specifically, we: (1) characterized species‐specific phenology among plants and insects at two High‐Arctic sites—Cambridge Bay in Nunavut, Canada, and Zackenberg in Northeast Greenland; (2) quantified competition for flowers using sticky flower mimics; (3) used information on plant–pollinator interactions to quantify supply and demand for pollinator services versus flower resources during the summer; and (4) compared patterns observed within a focal summer at each site to patterns of long‐term change at Zackenberg, using a 25‐year time series of plant flowering and insect phenology. Within summers, we found evidence of a general mismatch between supply and demand. Over the 25‐year time series, the number of weeks per summer when resource supply fell below a standardized threshold increased significantly over time. In addition, variation in resource availability increased significantly over years. We suggest that the number of resource‐poor weeks per year is increasing and becoming less predictable in the High Arctic. This will have important implications for plant pollination, pollinator fitness, and the future of the Arctic ecosystem, as both plants and their pollinators are faced with widening resource gaps.

Background Cellulitis caused by Escherichia coli is a common cause of condemnation of broiler chickens at slaughter worldwide and is associated with economic losses and a possible negative impact on animal welfare. The study objective was to monitor clinical signs and immune responses after subcutaneous E. coli inoculation (1.1–1.8 × 10⁷ CFU), aiming to induce cellulitis. Three groups of broiler chickens (n = 15/group) were inoculated with well-characterized E. coli strains (group A: ECA18 O24:H4/ST117 and group B: ECB11 O153:H9/ST38) or with saline (control) at 22 days-of-age. Clinical signs of disease, body weight and immune parameters were monitored until euthanasia 12–14 days after inoculation followed by post-mortem examination. Results The daily weight gain of the inoculated chickens was significantly lower one day after inoculation compared to the controls. Seven (23%) of the inoculated chickens displayed clinical signs: ruffled feathers, mild weakness, open-beak breathing and/or reluctance to stand, of which two birds were euthanized and one bird died. Five chickens in group B were observed with bacteraemia, which lasted up to three days after inoculation for two chickens. A transient increase in chicken mannose receptor MRC1L-B expression on circulating monocytes was observed one day after inoculation in both E. coli inoculated groups, with a more pronounced increase in group B. On day 7 after inoculation, the in vitro adherence of heterophils, monocytes and thrombocytes to the inoculated strain was increased in group B. Antibody titers to the inoculation strains were increased in some chickens in both groups on days 7 and 14 after inoculation, with the highest titers in group B. Seven (47%) and 13 (87%) of the chickens in group A and B, respectively, were diagnosed with cellulitis at post-mortem examination. In most birds, lesions consisted of plaque-like material embedded in the subcutaneous tissue of the abdominal wall. Conclusions Inoculation of E. coli caused cellulitis and prompted a rapid activation/redistribution of circulating monocytes followed by antibody production. The responses were most pronounced in chickens inoculated with E. coli strain ECB11, presumably because of a higher virulence.

Bats provide important ecosystem services for agriculture, such as pest control, a function that is particularly relevant for small-scale farmers. However, climate change is causing a decrease in bat populations. To assess the potential impacts of climate change on insectivorous bats and the implications on small-scale farming of indigenous communities in the Chiapas Highlands in southern Mexico we developed a three-step protocol: (1) projecting distribution shifts of insectivorous bats under climate change scenarios using non-dispersal and limited-full dispersal assumptions, (2) using official information to estimate the average economic value of conducting chemical pest control in crops at a state level, (3) surveying small-scale farmers to estimate the local economic value of pest control and determine how bats are perceived by small-scale farmers. Our models project shifts in bat species due to climate change. Given that new suitable climatic areas are also projected, if we assume a limited-full dispersal scenario, bats might not be as at risk by climate change, but shifting their distribution to more suitable habitats will probably affect the dynamic of the ecosystem service they provide. The official estimated value of chemical pest control is $15.15 USD/ha, while the estimated cost resulting from a hybrid survey with small-scale farmers was$47.53 USD/ha. The difference in cost could be related to an overuse of insecticides for pest control or an increase in price due to reduced accessibility. Sixty percent of surveyed farmers perceived a decline in bat populations, 68% were unaware of the benefits that bats provide to their crops, 51% believe that bats are mainly hematophagous, and 10% recognize that people harm or kill bats. A new approach including communicating small-scale farmers in their native languages the benefits that insectivorous bats provide along with a pest management strategy for the efficient use of insecticides needs to be implemented.

Electrofishing is a common method for sampling fish in rivers. In Sweden, electrofishing has a long history, dating back to the 1950s, but the vast majority of surveys have been conducted by wading in shallow river stretches, leaving a data gap for non-wadable rivers. Boat electrofishing allows for surveys in deeper river sections, but limited numbers of operational electrofishing boats have led to standardisation of methods not being prioritized within Swedish water management. This method protocol describes the first Swedish standardised method for boat electrofishing, based on intermittent shoreline sampling in larger slow-flowing rivers. The paper describes:•General methodology for boat electrofishing operation •Data collection protocols •Discussion of current caveats for the method In the future, the methodology will be amended to cover a wider array of river types (e.g. faster flowing river sections). Hence, readers are advised to look for updates to the protocol.

Paperbark maple (Acer griseum), an endemic and endangered wild plant in China, has red-colored autumn leaves of high ornamental and garden application value. Leaf color change serves as a crucial indicator for evaluating garden tree aesthetics; however, research on A. griseum's leaf color change remains limited. This study aims to elucidate the physiological and molecular mechanisms underlying leaf color change in maple leaves through physiological, transcriptional, and metabolic assays. Data analysis encompasses gene expression levels and metabolite changes in three distinct states of maple leaves: green, half-red, and red. The progessive decrease of chlorophyll and carotenoids and the continuous accumulation of anthocyanidins caused a sharp change in leaf coloration, which was most drastic in the green to half-red period. Subsequently, targeted metabolomics analysis was performed, and a total of 71 anthocyanidins were detected, and the content of eight types of anthocyanidins increased significantly in the half-red and red periods, compared with that in the green period; of which the multiplicative difference was the largest for cyanidin-3,5-O diglucoside, delivering the largest multiplicative difference. Thus, it was plausible that cyanidin-3,5-O-diglucoside-dominated compoundswere likely to be the main metabolites associated with leaf reddening. Correlation analysis revealed that 12 key transcription factors (TFs) were significantly correlated with the anthocyanin-related metabolites and structural genes, which play important regulatory roles during the biosynthesis of anthocyanosides in A. griseum. These findings offered useful insights into the molecular basis of leaf color variation in A. griseum; providing valuable information to guide targeted genetic breeding and varietal improvement strategies.

Elderberry ( Sambucus spp.) is an emerging and popular specialty crop in North America and worldwide. Both the fruit and flowers are being increasingly consumed because of their proven health benefits, mostly in the form of dietary supplement products. We explored changes in consumer knowledge and purchasing preferences regarding elderberry products after comparing results of a survey conducted in 2022 with those of a previous study conducted in 2011. Findings based on responses from 1036 US residents revealed that 41.2% had previously consumed elderberry products. This marks a significant increase from the 6.9% reported in the 2011 survey. Elderberry-based vitamin supplements were the most consumed elderberry product reported in the survey. Approximately half of the respondents reported consuming this product, which is an approximately seven-fold increase from 7.0% reported in 2011. We noted a change in purchasing venues, with more than 50% of participants purchasing elderberry products from grocery stores in 2022 compared to 43% in 2011. An analysis of a discrete choice experiment revealed that, among selected product attributes, organic and pesticide-free production of elderberries were the most important attributes. Statistical results of the choice experiment suggested that consumers were willing to pay, on average, US$3.51 more per 12-ounce (355 mL) bottle of juice made from organic elderberries and an even higher premium of US$3.97 more per bottle of pesticide-free elderberry juice compared to that for juice made from conventionally grown elderberries. We also estimated that consumer products made with American-grown elderberries would garner a 13% price premium over elderberries grown in Europe. Elderberry products with carbon neutrality elicited a 13% premium per bottle of juice (approximately US$1.91 more per bottle) compared to that of those without disclosure of the carbon emission information. In summary, elderberry products labeled as pesticide-free, locally produced, and carbon-neutral are likely to offer the greatest market appeal to US consumers and would further contribute to the mainstreaming of elderberry products.