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Background: Overexpression of sialic acids on glycans, called hypersialylation is a common alteration in cancer that drives immune evasion via interaction with Sialic acid-binding immunoglobulin-like lectin (Siglec) immunoregulatory receptors on tumor-infiltrating immune cells. Myeloid derived suppressor cells (MDSCs) generated by cancer-induced aberrant myelopoiesis are highly immunosuppressive cells inhibiting immune cells via direct interaction or secretion of suppressive cytokines. Targeting the complex suppressive tumor microenvironment (TME) remains a challenge. Methods: Siglec expression of murine and human MDSCs in healthy conditions and tumor setting was assessed by flow cytometry. Functional analysis of Siglec-E knockout on MDSCs in mice was evaluated using SigE-LysMCre mice and suppressive capacity was tested in vitro in combination with SiglecE blocking and cleavage of Sialoglycans using Sialidase. Results were confirmed in the human setting using an in vitro assay to generate MDSC-like cells including RNA-Sequencing and a MDSC suppression assay with cancer-derived MDSCs. Results: MDSCs express multiple inhibitory Siglec receptors in humans and mice. Knockout of SiglecE in the myeloid compartment in vivo resulted in prolonged survival and increased T cell infiltration compared to litter mates expressing Siglec-E. Of note, desialylation of MDSCs and Siglec-E blocking in vitro reduced MDSCs suppressive function against T cells. Similarly, reducing Sialoglycans by Sialidase in human MDSC generated in vitro resulted in increased suppressive capacity and downregulation of functional MDSC markers on RNA level. Findings were validated with lung cancer patient derived MDSCs. Conclusion: Our results provide first insights into the importance of the Siglec-Sialoglycans axis to modulate MDSCs in the TME. Targeting glycosylation of MDSCs with Sialidase reduces their suppressive capacity making it a powerful approach to improve cancer immunotherapy. Further studies are needed to reveal the underlying mechanisms. Citation Format: Ronja Wieboldt, Andreas Zingg, Emanuele Carlini, Anastasiya Börsch, Heinz Läubli, Natalia Rodrigues Manutano. Disturbing the Siglec-Sialoglycan axis to target myeloid- derived suppressor cells in the tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1259.

Fast track microfluidic screening of the antibody repertoires of 12 convalescent COVID-19 donors comprising 2.8mio antibodies yielded MTX-COVAB, a human-derived monoclonal antibody with low picomolar neutralization IC50 of SARS-CoV-2. COVAB neutralization potency is on par with the Regeneron cocktail as demonstrated in a comparative neutralization assay. MTX-COVAB shows strong efficacy in vivo and binds to all currently identified clinically relevant variants of SARS-CoV-2. MTX-COVAB completes GMP manufacturing by the end of this year and will be tested in the clinic in March 2021.

Plentering with pines – results from the United States Until now, scientifically reliable data on plentering of light-demanding tree species in Europe have been lacking. This gap is filled with long-term trials from the USA, among others with southern yellow pines. In the southern state of Arkansas, two plots of 16 hectares were installed in 1936, in the context of a large-scale trial of mixed loblolly pine (Pinus taeda L.) and shortleaf pine (Pinus echinata Miller) stands, in which plentering has been applied using single-tree harvest of predominantly sawtimber-sized trees (dbh >30 cm) with natural regeneration. The aim of the experiment is to investigate the possibilities and limits of uneven-aged silviculture with shade-intolerant tree species, and whether this can be applied in cutover southern yellow pine stands in order to improve the stand structure, to increase growth, and to make periodic harvests possible. The two plots were in different initial states – one more or less fully stocked, the other with poor initial stocking. Since 1936, 18 complete surveys have been conducted where all trees 10 cm and larger were tallied by diameter. During that same time period, 14 plenter harvests have been carried out using the Volume Control-Guiding Diameter Limit method in both plots. In order to check the variability of stand structure within the 16-hectare stands, each was subdivided into four quarters, and the diameter distributions were compared within each quarter. The uneven- aged structure was checked by a sample of tree-ring counts. Both stands retained continuous canopy cover throughout the observation period. The initial differences in the number of stems, the basal area, the standing volume, the proportion of sawtimber, the average basal area and the mean quadratic diameter dg became alike in the course of time, which shows the flexibility of plentering and the tendency to develop stands where the harvest of growth appears to be sustainable. The dg of the harvest was initially slightly more than 20 cm, but is today more than 50 cm. The average total growth is 6 m3/ha and year. The results show that these stands are uneven-aged stands in an advanced stage of the transformation to plentering. We suspect that in the absence of a major natural disturbance event, the plentering approach in southern yellow pines will continue to be promising in the future.

New forest edges are continuously being created by forest management. In the Swiss Alps, silvicultural treatments have partly changed from the selection cutting widespread two decades ago to a more intensive strip cutting. However, little is known about the impact of such harvesting on tree growth and on the structural development of Alpine forest stands dominated by Norway spruce (Picea abies (L.) Karst.), which have high economic and protective value. We therefore investigated the effect of strip cutting in four Alpine spruce stands differing in site and stand conditions through a dendrochronological analysis of 134 tree stems. The change in growth rate was assessed for the 10-year period before and after the cutting year, and rate changes in edge and non-edge trees were compared. The relative change in Hegyi’s competition index before and after the cut was used as a proxy for the change in space and related resources. A linear model was developed to assess the effects of biotic and abiotic variables on changes in growth after strip cutting. Radial growth responses varied greatly between the stands, with a significant increase only in edge trees in the two north-facing sites, i.e. 12% and 60%. Changes in tree competition had the strongest impact on tree growth, followed by site effects. With the same relative change in competition index, the radial growth of edge trees increased more strongly in reaction to cutting than that of non-edge trees. Additionally, small-diameter trees growing near edges benefited more from the strip cutting than larger trees. Our results suggest that strip cutting on north-facing slopes can boost the growth of trees on the east and north-east-facing forest edges. Small spruce trees growing along newly created forest edges can be kept to enhance stand yield. As cutting often leads to long forest edges and may thus affect the growth of a significant proportion of the forest area, such effects should be considered in planning cutting layouts.

The optimization of forest management under climate change uncertainty requires a comparison of many alternative management options under different climate scenarios and the use of stochastic and adaptive approaches. Empirical growth and yield models are highly suitable for this, provided they include sensitivity to environmental influences. Here, we present a climate-sensitive empirical growth and yield model that is based on the direct integration of environmental effects in dynamic growth and survival functions, which allows for the evaluation of changing site conditions over time. Individual-tree diameter and height growth and the probability of a tree to survive any 5-year period were modelled for even-aged beech (Fagus sylvatica) stands in Switzerland using a distance-independent approach. Changing site conditions were based on a drought index (locally adjusted water balance) and sum of degree-days. The data for fitting the model were taken from 30 permanent yield plots repeatedly measured from 1930 to 2010. Reasonable results were obtained in the model evaluation: (1) validation against independent National Forest Inventory data indicated that the incorporation of drought and sum of degree-days in the model was appropriate; (2) accurate simulations over around 50 years of past stand development were achieved (for changes in basal area over 5-year measurements in all plots, the bias was 3 % and the root mean square error 32 %); and (3) the impact of climate change may vary considerably along the range of current site conditions. We thus conclude that the model can be used in management planning under climate change uncertainty.

In this paper we investigate how to measure real world performance of Android devices using app start durations. To this end we collect ground truth app start times using an automated mechanical setup. The ground truth start times are highly correlated with the outputs from Android's ActivityManager, which we then use to obtain app start times during normal use on a range of rooted devices. We then predict app start times with supervised learning to detect if device performance has changed over time. We show that training data can be gathered on a small set of rooted devices and then applied to other, non rooted devices. We also present an unsupervised method that can track the evolution of the system performance without requiring root access at all.

From the perspective of academic and small research laboratories, the most common and practical strategy for recombinant expression of full-length monoclonal antibodies is to perform transient plasmid transfection of mammalian cells, resulting in small-scale and limited protein production. The generation of stable antibody producing mammalian cell lines enables larger-scale and consistent expression, however this approach is rarely pursued due to the time-consuming and expensive process of single colony screening and characterization. In order to bridge the gap between the simplicity of transient transfection and consistent production by stable cell lines, we describe a method to stably integrate antibody genes into the endogenous immunogenomic loci of hybridoma cells using CRISPR/Cas9 genome editing. Initially, the antibody variable light (VL) chain is deleted by multiplexed Cas9 cleavage; subsequently, the variable heavy (VH) chain is replaced by a fluorescent reporter gene (mRuby) by Cas9-assisted homology-directed repair (HDR). This cell line is customized by replacing mRuby with a synthetic antibody (consisting of a VL, light constant region and VH) by once again using Cas9-assisted HDR. Due to hybridomas' inherent ability to surface display and secrete antibodies, they provide a suitable host for both the selection and the production process, substantially streamlining the process for stable cell line generation, and thus we refer to this platform as plug-and-(dis)play (PnP) hybridomas.

High-throughput sequencing of immunoglobulin (Ig) repertoires (Ig-seq) is a powerful method for quantitatively interrogating B cell receptor sequence diversity. When applied to human repertoires, Ig-seq provides insight into fundamental immunological questions, and can be implemented in diagnostic and drug discovery projects. However, a major challenge in Ig-seq is ensuring accuracy, as library preparation protocols and sequencing platforms can introduce substantial errors and bias that compromise immunological interpretation. Here, we have established an approach for performing highly accurate human Ig-seq by combining synthetic standards with a comprehensive error and bias correction pipeline. First, we designed a set of 85 synthetic antibody heavy-chain standards (in vitro transcribed RNA) to assess correction workflow fidelity. Next, we adapted a library preparation protocol that incorporates unique molecular identifiers (UIDs) for error and bias correction which, when applied to the synthetic standards, resulted in highly accurate data. Finally, we performed Ig-seq on purified human circulating B cell subsets (naïve and memory), combined with a cellular replicate sampling strategy. This strategy enabled robust and reliable estimation of key repertoire features such as clonotype diversity, germline segment, and isotype subclass usage, and somatic hypermutation. We anticipate that our standards and error and bias correction pipeline will become a valuable tool for researchers to validate and improve accuracy in human Ig-seq studies, thus leading to potentially new insights and applications in human antibody repertoire profiling., Frontiers in Immunology, 9, ISSN:1664-3224

From the perspective of academic and small research laboratories, the most common and practical strategy for recombinant expression of full-length monoclonal antibodies is to perform transient plasmid transfection of mammalian cells, resulting in small-scale and limited protein production. The generation of stable antibody producing mammalian cell lines enables larger-scale and consistent expression, however this approach is rarely pursued due to the time-consuming and expensive process of single colony screening and characterization. In order to bridge the gap between the simplicity of transient transfection and consistent production by stable cell lines, we describe a method to stably integrate antibody genes into the endogenous immunogenomic loci of hybridoma cells using CRISPR/Cas9 genome editing. Initially, the antibody variable light (VL) chain is deleted by multiplexed Cas9 cleavage; subsequently, the variable heavy (VH) chain is replaced by a fluorescent reporter gene (mRuby) by Cas9-assisted homology-directed repair (HDR). This cell line is customized by replacing mRuby with a synthetic antibody (consisting of a VL, light constant region and VH) by once again using Cas9-assisted HDR. Due to hybridomas' inherent ability to surface display and secrete antibodies, they provide a suitable host for both the selection and the production process, substantially streamlining the process for stable cell line generation, and thus we refer to this platform as plug-and-(dis)play (PnP) hybridomas.

Aim of this study was to determine the long- term effects of thinning regime with different intensities on the stand and tree social classes development, particularly regarding the old question of compensative effect between stocking and girth improvement using the example of Douglas-fir. Data provide from a thinning experiment in one site of Swiss Central Plateau, from age 11 until 41 years containing six treatment variants (three planting densities and two level of stand density) repeatedly mea- sured six times, as well as from seven permanent yield plots times series aged between 17 and 127 years. We present as well the real observed characteristics in term of stem numbers distribution, diameter increment per d.b.h. categories, as results from simulation over the whole pro- duction time until 105 years with an appropriate growth simulator, in terms of net value increment (MAIv). Our results show that the effect of thinning works mainly on the social medium categories, in terms of number and girth improvement. Social dominant trees are more or less untouched by thinning, demonstrating that there are in every stand a quite important number of self-dominating trees which do not need particular silvicultural help to maintain their dominant status in the upper storey. The expected compensation between stem number reduction and girth improvement shows that the remaining stand density is determinant on the net value level. The so-called mass effect seems really more effective. The best way to improve a stand value appears to be artificial pruning. Because a thinning regime should not consider only the economic productivity but take in account risk, stability and resilience and particularly the way of renewal, we suggest a way for optimising the thinning regime com- bining effect of biological rationalisation and risks.

1AbstractMany studies have predicted large changes in forest dynamics during the next century because of global warming. Although empirical approaches and studies based on species distribution models provide valuable information about future changes, they do not take into account biotic interactions and stand-level demographic variations. The objective of this study was to quantify the local and regional variability of the growth and regeneration of three important forest species growing often in mixed stands in Europe (Picea abies (L.) Karst., Abies alba Mill., Fagus sylvatica), and to assess the climatic drivers of this variability. For that purpose, we collected a large forestry data set compiling the long-term (up to 100 years) evolution of species and size distributions for 163 stands across Europe, in the mesic distribution area of these forests. We used an inverse modeling approach, Approximate Bayesian Computation, to calibrate an individual-based model of forest dynamics on these data. Our study revealed that the variability of the demographic processes was of the same order of magnitude between stands of a same forest as between different forests. Out of the three species and two demographic processes studied, only the fir growth strongly varied with temperature. Water availability did not explain any demographic variation over stands. For these forests experiencing mesic conditions, local unmeasured factors seem therefore to have an influence at least as important as macro-environmental factors on demographic variations. Efforts to include these important factors in projection scenarios should therefore be prioritized. Besides, our study demonstrates that inverse modelling methods make possible the analysis of long-term forestry data. Such data should therefore be more widely compiled and used for ecological and global change research.

The impact of climate change on the soil microbiome potentially alters the biogeochemical cycle of terrestrial ecosystems. In semi-arid environments, water availability is a major constraint on biogeochemical cycles due to the combination of high summer temperatures and low rainfall. Here, we explored how ten years of irrigation of a water-limited pine forest in the central European Alps altered the soil microbiome and associated ecosystem functioning. A decade of irrigation stimulated tree growth, resulting in higher crown cover, larger yearly increments of tree biomass, increased litter fall, and greater root biomass. Greater amounts of plant-derived inputs associated with increased primary production in the irrigated forest stands stimulated soil microbial activity coupled to pronounced shifts in the microbiome from largely oligotrophic to more copiotrophic lifestyles. Microbial groups benefitting from increased resource availabilities (litter, rhizodeposits) thrived under irrigation, leading to enhanced soil organic matter mineralization and carbon respired from irrigated soils. This unique long-term study provides new insights into the impact of precipitation changes on the soil microbiome and associated ecosystem functioning in a water-limited pine forest ecosystem and improves our understanding of the persistency of long-term soil carbon stocks in a changing climate. This article is protected by copyright. All rights reserved.

In this contribution we present the results of a Swiss-Italian joint sylvicultural experiment to verify if and how the single-tree-oriented silviculture can be applied to chestnut coppices to enhance timber production for industry and structural timber. The study was carried out in five 7 to 17 years old, pure chestnut coppice stands growing on sites of medium to good fertility in central Italy and southern Switzerland. The single-tree-oriented silviculture (option A, 100-150 target trees per hectare) was compared to the stand-oriented silviculture (option B) and to the natural evolution (option C) in terms of growth performance (i.e. individual annual radial increment), stand stability and efficiency (namely leaf area index [LAI], incidence of game and gall wasp attacks, harvesting damages). Suitability of the different treatments has been evaluated on effective (Option A) and theoretical (Options B and C) target trees as selected at time of the first thinning. First results show a significant higher increment response of the target trees in option A compared to the two other silvicultural systems, and a general fast and dynamic recovery of canopy cover after the thinnings in both silvicultural treatments, but even more in the single-tree-oriented silviculture, where two thinnings were necessary within few years. Due to the short time since the arrival of the gall wasp at the experimental sites, no clear impact patterns have been detected. Nevertheless, the attack severity seems to be higher in the target trees of the A option. Damages caused at the stem base by red deer or harvesting operations were clearly higher in the option A, which may reduce the positive outcome of this slvicultural option.

In Valais, a dry Inner-Alpine valley in Switzerland, increasing tree mortality has been related to drought and reduced forest management, which have led to increased competition between trees. Since increasing drought and reduced forest management were co-occurring during the last decades, it is not clear if forest management alone could increase tree resistance to drought. To test whether thinning of Scots pine (Pinus sylvestris L.) stands could be used to mitigate the effects of drought, we analyzed a long-term thinning trial set up in xeric Pfynwald forest in 1965. The trial featured one control (unmanaged plots; basal area 40m2ha−1) and three thinning intensities; light (33m2ha−1), medium (22m2ha−1) and heavy (11m2ha−1). Thinning was repeated in 1971, 1978 and 2010. Individual tree radial growth responses and tree leaf area to sapwood area ratio were assessed and compared among treatment. Additionally, stand-level growth, tree mortality and the relationship between stand density and tree diameter (allometric slope r) were analyzed and compared between two periods (1978–1990; 1991–2009) where the last period was drier. Individual tree basal area increment increased significantly for up to three decades after heavy thinning and mortality rates decreased with decreasing basal area while stand-level growth did not significantly differ. The higher mortality rate and the more negative allometric slope r in the second period suggests that site conditions have become hotter and drier and can partially explain a decrease in the basal area in the control plots and in the light thinning treatment. Leaf area to sapwood area ratio increased with lower basal area and suggests that competition for water was reduced. Taken together, our results suggest that a reduction in basal area of 40–60% to ca. 15–25m2ha−1 could mitigate drought effects on Scots pine on xeric sites for the coming decades prolonging the provision of important ecosystem services. After this time, sustainability of Scots pine forests at xeric sites will depend on the intensity of anticipated climate change, so that in the worst case, thinning might be applied to convert Scots pine forests to mixed forests with more drought-resistant species.

Dynamics of dense, uniform spruce-dominated mountain forests Dense, uniform stands have increased in spruce-dominated mountain forests during the last century and often cause silvicultural problems. During recent years, different research activities at Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) have addressed the development of such mountain forests with or without active management. For this, plots of the Swiss National Forest Inventory (NFI) between 1983/1985 and 2004/2006 have been analysed, dendroecological methods have been used to investigate competition and selfthinning processes and a reassessment of WSL long-term investigation plots has been conducted. NFI plots of stands which have already been dense during the first inventory period generally showed increasing basal area, stagnating stem numbers, strongly increasing amounts of deadwood and slightly increasing regeneration levels, both in managed and in unmanaged stands. Dendroecological field studies confirm that trees in the generally about 80 to 150 years old stands were strongly affected by competition-induced self-thinning and subsequent small-scale mortality processes few decades after stand initiation already. WSL long-term investigation plots generally confirm this dominance of relatively small-scale processes, but also show potential for silvicultural interventions, especially in early stages of self-thinning. According to the guidelines for silvicultural intervention in forests with protective functions (NAIS), an active management of later self-thinning stages with already short crowns and higher mortality should focus on stands where risks have to be considered as too high, based on hazard and damage potential and the size of the dense, uniform stands.

The mixture of beech (Fagus sylvatica L.) and oak (sessile oak, Quercus petraea (Matt.) Liebl., and pedunculate oak, Q. robur L.) is of considerable importance in Europe and will probably become even more important under climate change. Therefore, the performance of oak and beech in mixture was compared with the species’ growth in pure stands. Data from 37 long-term mixing experiments in Poland, Germany and Switzerland were pooled for analysis of mixing effects on stand productivity and possible interrelationships with mixing portions or site conditions. We found that on average, mixed stands of oak and beech exceeded biomass productivity in pure stands by 30 % or 1.7 t ha−1 year−1, as the growth of both species was benefitted by the mixture. However, that the interaction actually ranged from facilitation and overyielding on poor sites to underyielding on fertile sites triggered by competition. An empirically derived interaction model showed volume and dry mass growth changing in mixed stands from gains of 50 % to losses of 10 % depending on site conditions. It is concluded that the analysed mixture grows in accordance with the stress-gradient hypothesis and that our results suggest a site-specific relationship between species mixture and biomass productivity. As a consequence, an adequate species mix should result in increased productivity under steady state as well as climate change.

Gap models are flexible tools for the simulation of forest dynamics under different climatic conditions. An important area, however, has not yet received the attention it deserves: the formulation of height growth and maximum tree height. In most gap models, every tree approaches a fixed maximum height regardless of site conditions, and tree height as such is approximated via stem diameter. To address these issues, we converted maximum height from a parameter to a variable that depends on site-specific climatic conditions. We also established tree height as a separate state variable besides diameter, to allow for competition effects to influence the ratio between height and diameter growth. The new model formulations were tested against data from the Swiss National Forest Inventory (NFI) and from a forest growth and yield research plot. Lastly the new model version was applied to study productivity changes due to climate change along an environmental gradient. The new model formulations increased the accuracy of simulations of stand characteristics without negatively influencing the general applicability of the model. The height/diameter relationship of a Douglas-fir stand in Switzerland simulated with the new model version resembled measurements closely, and biomass simulated along an environmental gradient agreed better with measurements (NFI) when using the new model version. Simulations with site-specific maximum height showed that the maximum heights of the dominant species on the gradient did not differ significantly from NFI data, whereas static maximum heights did. The application of the old and new model versions to simulate productivity under climatic change along the same environmental gradient showed that the conversion of a static parameter such as maximum height to a site-specific variable is not only a desirable, but a crucial feature to incorporate, since climate-induced changes in productivity are simulated to be more pronounced with the new model formulation. We conclude that dynamic height growth and site-specific maximum tree height can significantly improve simulation results of forest succession models, especially with regard to forest management under climate change.

Summary 1. The empirical study of forest ecosystem dynamics is difficult because of the longevity of trees. Many types of models were developed to assist with this problem, all of them with advantages and disadvantages. The strengths of gap models are that they are able to simulate forest dynamics under changing climatic conditions and are therefore suitable for exploring future forest dynamics. 2. Most temperate and boreal forests are managed, making it important to incorporate harvesting functions depicting a wide range of silvicultural practices into the models and to test them under different climatic conditions. This is a necessary prerequisite to the application of these models under climatic change scenarios. Most gap models, however, do not feature such submodels, which disqualifies them as decision support tools. 3. We implemented a management submodel in the gap model ForClim that is able to simulate a wide range of cutting and thinning techniques, including continuous cover forestry (‘plentering’). We tested the new submodel against long-term data (72–111 years) from eight growth and yield research plots across climatic conditions ranging from warm-dry to cold-wet. 4. Stem numbers were simulated accurately in nearly all cases, basal area showed a good fit on Quercus-dominated plots, but an over/underestimation on Fagus sylvatica-dominated and Picea abies-dominated plots. The diameter distributions simulated for the time of the most recent inventory did not differ significantly from empirical data except for two cases. Harvested basal area and stem numbers mostly agreed well with empirical data, but showed the same deviation from reality as simulated basal area. 5. Simulations run with an accurate management plan taken from foresters’ reports for the plots yielded nearly the same results as those run with a generic management setting. 6. Synthesis and applications. We have demonstrated that (i) the management submodel adequately depicts silvicultural treatments, including continuous cover forestry; (ii) a generic harvesting setting can be substituted for a very detailed one, thus eliminating a major source of uncertainty in assessments of future forest dynamics; and (iii) as the new version of ForClim is able to deal with widely differing current climates, it can be employed with reasonable confidence to simulate future management strategies under climatic change. Overall, this modelling work is a major step towards the use of succession models as decision support tools in forest management.

Between 1995 and 2008 the granting of the Binding Forest Award led to fresh cooperation between forest owners and research on silviculture, growth and yield at the Swiss Federal Institute for Forest, Snow and Landscape Research. Various topics were treated: a study of the beech coppices in Rothenfluh rapidly made it clear that very little was known about this formerly widespread type of forest management and its consequences. The same was true to a lesser extent for the conversion of rather uniform high forest into selection forest (in Plasselb), and for the selective management of light demanding tree species, such as the oak, in Rheinau. In Boudry, cooperation between practice and research already existed: the prize award here led to new approaches in the production of high quality oak, whilst taking ecological values into account. All these new projects are still in their earliest stages and will call for a great deal of “sustainability”, in both senses of the word, from all those involved. Considering the long periods of time required for the development of forest ecosystems, this is in fact self-evident.

Adequate management practices to attain the profiles specified in the Swiss guidelines for the management of mountain protection forests are not always unequivocally clear. This applies among others for beech forests that have a protective function against rockfall. We defined two management scenarios, one of which aims at harvesting trees starting with a minimum diameter at breast height of 40 cm, whereas the other one is focused on the creation of small gaps (area of 500 m2) over a maximum of 10% of the total stand area. These scenarios along with a control scenario characterized by no management were studied using the forest growth model BWINPro. In the control scenario, number of trees, basal area and standing volume were highest. The developments simulated under the two management scenarios were similar, when in scenario thinning harvesting levels corresponded to the growth over a 10-year period. In the other cases, number of trees, basal area and standing volume are lower under scenario gap because harvesting interventions occur more regularly. If the rocks have a volume exceeding 0.2 m3, the requirements of the profiles are attained more quickly under scenario gap, because in scenario thinning the larger trees are preferentially harvested. Because tree regeneration was not simulated, it is difficult to realistically predict the development of the number of trees. However, management interventions are needed in such forests, particularly if the profile for rocks with a volume below 0.2 m3 is to be attained and maintained.

Drought during the vegetation period has en effect on tree growth. Using daily precipitation data and growth records from long-term research plots, we investigated what can be defined as “drought” and how strong its effect is. Dry or humid periods are defined as the deviation from the long-term daily mean of precipitation. Such periods must last at least 60 days to be considered as being decisive for tree growth. The drought values are used together with other site and stand parameters as explaining variables in a model for the basal area increment for Norway spruce (Picea abies [L] H. Karst.), silver fir (Abies alba Mill.), European beech (Fagus sylvatica L.) and oak (Quercus L), based on data from long-term growth and yield plots which are located in the neighbourhood of precipitation measurement stations. These models explain 55 to 89% of the variance. In drought situations basal area increment drops clearly for spruce and beech, for fir only weakly and oak shows no reaction. Furthermore, we checked if there happened additional or compulsory felling after drought periods and if the basal area growth changed significantly compared to the growth in the period before. For both it is not the case, despite distinct drought periods in the last century, especially in the 40s with the extreme year of 1947. Therefore we do not expect dramatic changes for the investigated species in similar drought situations under the prerequisite that the other conditions do not change essentially.

Studies on the production and yield of forests in Switzerland depend entirely on collaboration between owners and forestry services. Not a single square meter of trial area on which to conduct experiments or studies actually belongs to the research institute. The trial areas are spread across the country and their location owes nothing to chance; there are relatively few such areas in Canton Neuchâtel. The present article traces the history and the current situation regarding yield studies in this canton and presents some conclusions. Populations of spruce and beech served only to produce yield tables for FLURY (1907). Plenter forest areas still exist that serve to illustrate long term growth development, the balance of the situation and total growth performance. The oak stands at Boudry are representative of older oak populations.

Silviculture is under pressure, as are other areas of applied science. Central specialist forest sciences, such as silviculture,growth and yield or forestry establishments etc., are losing ground due to the division made between basic and applied research and quickly losing their importance in the university landscape. It is only in the German-speaking countries that silviculture and growth and yield are two separate specialist areas and thus not taught in combination with one another. Growth and yield is a scientific basis of silviculture. In its widest sense, siliviculture is a system and can be viewed as a standard circle of diverse activities, each of which has its own scientific problems. Silviculture is an important area of research that is struggling to maintain its hold in today's rapidly changing research landscape–above all because this discipline calls for long-term research. Only long-term silvicultural research will furnish a quantifiable and objective foundation for a modern,ecologically oriented management of the forest.

Stand structures and stand stability in unmanaged Norway spruce forests in the Swiss mountains may decline and their protective function against natural hazards will thus be put at risk. They are being subjected to thinning operations to improve stability and, in the long-term, to transform them into mountain selection forests. On pairs of research plots – thinned and not thinned – we will closely follow the stand development. Preliminary results indicate that the best variables to describe the effectiveness of the applied treatment to the stand structures are the h/d ratio,the spatial distribution and the stand density index.

Une etude sur la capacite a rejeter de souche du châtaignier (Castanea sativa Mill.) a ete effectuee dans un taillis d'environ 60 ans d'âge en Suisse au sud des Alpes. La coupe de taillis s'est faite par l'elimination de tous les arbres vivants et morts. Un inventaire des rejets de souche a ete realise apres deux, respectivement quatre ans afin d'analyser la croissance et la mortalite du nouveau peuplement et de verifier les facteurs influencant la capacite a rejeter de souche. La mortalite des souches est de 4 %, le nombre de rejets par souche (48) est eleve et la croissance des rejets remarquable. La structure du peuplement, la densite des souches et la dimension des vieilles souches n'ont pas d'influence negative sur la capacite de production des rejets ou sur la croissance en diametre et en hauteur de ceux-ci. Par contre on observe que la qualite de la coupe de la souche a un effet positif. En conclusion, la mesure de la hauteur du rejet dominant peut servir comme un indicateur valable de la vigueur de la regeneration dans un taillis de châtaignier.

This work presents the results of a validation study using the forest growth simulation model MOSES 3.0 for Swiss forest conditions. During the latest parameterization of the model a large data set from Austria as well as Switzerland was used. The goal of this work was to validate the diameter and height increment functions using a large and independent data set (not used for model calibration) recorded on permanent sample plots in Switzerland. Tree growth was simulated over several growth periods and analyzed for a possible bias. The main results of this study suggest that no systematic discrepancies exist between the predicted and the observed diameter and height increment.

Forest patch models have been applied to simulate forest development and long-term forest succession in many studies. The main focus of these simulations has been on species composition and biomass in natural forests, but these models could also become useful for the prediction of other structural forest patterns such as size distributions. Up to now, most of these models have been validated by approaches such as comparison of simulation results with potential natural vegetation (PNV), or national forest inventory data. While these approaches may be appropriate to validate the simulated species composition, they are not sufficient in testing the prediction of other structural patterns. Thus, little is known about the accuracy of forest patch models in simulating structural forest patterns such as size distribution of different forest types. For this reason, we tested the forest patch model ForClim against empirical data from three Swiss mountain forests. The objectives of this study were: (i) to investigate the performance of ForClim in simulating structural forest patterns and (ii) to assess the influence of the regeneration, growth and mortality submodels of ForClim on the simulation results. Several shortcomings of the model were identified and quantified. In particular, the stress-induced mortality implemented in ForClim was found to overestimate the actual mortality rates. The excessive mortality was most likely caused by an inaccurate growth function or an overestimation of light competition. Once the stress-induced mortality was reduced, ForClim was able to reproduce structural forest patterns in an accurate manner. Based on these encouraging results, we suggest that ForClim as well as other forest patch models could become important tools for further applications in forest research.

Dürsrüti is an example for an extreme variation of a selection forest that is characterised by its very high standing volume over a long period of time. Dürsrüti is also a part of Swiss forestry history: timber marking of the famous thick silver firs,of which only one remains, was reserved for high officials from the federal administration and from research institutions. Dürsrüti has been a research area of the growth and yield research since 1914. The development of the stem numbers,standing volume, increment, utilisation, diameter distribution,diameter class proportions and other parameters relevant to growth and yield are shown, interpreted and compared with the research area Hasliwald in Oppligen. The tree giants in the Dürsrüti forest are also examined. The features of this forest as a selection forest are compared with models according to MEYER (1933) and SCHÜTZ (1975, 1999). Dürsrüti forest has undergone a dramatic change in the last decades, which is expressed in the sharp decrease of the standing volume. Nonetheless, it can be concluded from the available long-term data that the forest in Dürsrüti unreservedly fulfils its function.

The forests of the Schlagl-Monastery in the north-eastern corner of Austria are managed according to Reininger’s [Osterreichischer Agraverlag, Vienna, Austria, 163] idea of target diameter harvesting. Twenty years of observations in a 3.5 ha Norway spruce stand in Schlagl and the first re-observation of a permanent inventory in the nearly 500 ha forest management district (FMD) Sonnenwald are investigated and reveal that indeed small trees make efficient use of the area they gain from the removal of their larger neighbours and that the growth per hectare is not decreased by target diameter harvesting. It seems that over a rather long period in the investigated stand and in all stands above 80 years the number of larger trees removed will be replaced by the growth of smaller ones. Comparing the stem number distribution with Schutz’s [Schweiz. Z. Forstwes. 126 (9) Romandes, 178] equilibrium model shows that the steady state is not yet achieved but is fast approached by target diameter harvesting. Probably the equilibrium stocking volume is somewhat below the current average stocking of 450 m3 ha−1.

Forestry and forestry research are confronted with a problem which is less pronounced in other fields: the length of time during which the processes must be observed and the long production times. These facts give rise to a number of specific features. Due to the rapid cultural, economic and social changes,questions to be answered by forestry research are dated by the time results are available. On the other hand, it is almost impossible to predict future developments and to adapt the research accordingly. The result is that the further development of forestry research as well as of forest management must concentrate on questions which encompass a broad spectrum of possible developments. This is demonstrated by new research plots for topics concerning continuous forest cover,montane spruce forests, chestnut coppices and the application of new methods and techniques.

International audience

This paper compares experimental growth and yield study plots with sample plots from forest inventories. The difference in research objectives leads to a situation where sample plots are available that are representative of the total population, but give only limited information on site conditions and management history. However, detailed information on site condition and management history is available for growth and yield plots, but does not represent the total population. As an example, Swiss growth and yield plots are compared with survey plots in terms of species distribution, stem form, slope class and elevation. A critical review is given of the two most common sampling designs for regional forest surveys. Continuous forest inventory is recommended over the more efficient but more complex sampling with partial replacement design for use in conjunction with growth and yield studies. The limitations of both growth and yield plots and sample plots are discussed. Recommendations for linking both types of plots to close information gaps are given to improve both forest surveys and growth and yield studies.

Producing quality chestnut timber from chestnut coppices by defining silvicultural approaches sustainable from the economic, ecological and socio-environmental point of view is a promising option for the future. Enhancing local silvicultural activities may turn in an improved quality timber production, in ecological benefits, in reducing of environmental loads related to timber import, and favouring direct and indirect (e.g., tourism) forestry industry in marginal areas. In our study we monitored the response of chestnut coppice stand to different silvicultural treatments: i) no treatment (control); ii) stand silviculture consisting in early and frequent low-thinning of moderate intensity; iii) single tree oriented silviculture consisting in early selection final target trees among the best phenotypes (up to 150 individuals per ha) and isolating their crown through free thinning in order to avoid any competition with neighbouring trees. Three experimental plots (1 in Canton Ticino, Switzerland and 2 in Toscana, Italy) were selected in homogeneous and fairly productive sites. First silvicultural interventions have been planned between January 2006 and February 2009 according to the development stage of the stand in each area. First results highlight the existence of both positive and negative aspects in all the considered options. A common trait among the thinned stands is the rapid recovery of the canopy within few years. Concerning the single tree silviculture, it allows producing a significantly higher increase in diameter of the target trees. But, it is disadvantageous in terms of extracting the harvested wood from the stand and it is highly susceptible to game damages. In the future we will carry on the research trials monitoring the considered silvicultural options also in terms of the overall economic balance.

International audience; This contribution presents a dynamic stand growth model for Beech (Fagus sylvatica L.) forests, based on a dataset provided by the Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf. The dataset includes 143 research plots, covering a wide range of growing sites and providing up to 16 interval measurements per research plot.* The objective of this research is to complement the range of existing beech growth models by bridging the gap between the historical yield tables and the single tree growth models. The specific aim is to develop transition functions which will project three state variables (dominant height, basal area and number of trees per hectare) at any particular time, in response to any arbitrary silvicultural treatment.* Two of the transition functions were derived using the generalized algebraic difference approach (GADA), the third one was derived with the algebraic difference approach (ADA). All the functions were fitted simultaneously using iterative seemingly unrelated regression and a base-age-invariant method. The influence of thinnings on basal area growth was included by fitting different transition functions for thinned and unthinned stands.* The overall model provides satisfactory predictions for time intervals up to 20 years. The new model is robust and its relatively simple structure makes it suitable for economic analysis and decision support.; Cette contribution présente un modèle dynamique de croissance des peuplements de hêtres (Fagus sylvatica L.), basé sur un ensemble de données fournies par l'Institut Fédéral Suisse de Recherche sur la Forêt, la Neige et le Paysage, WSL à Birmensdorf. L'ensemble des données comprend 143 parcelles de recherche, couvrant un large éventail de sites et fournissant jusqu'à 16 intervalles de mesures par parcelle de recherche.* L'objectif de cette recherche est de compléter la gamme de modèles de croissance du hêtre existants, en jetant un pont entre les tables de production historiques et les modèles de croissance d'arbre. L'objectif spécifique est de développer des fonctions de transition qui projeterons trois variables d'état (hauteur dominante, surface terrière et nombre d'arbres par hectare) à n'importe quel moment déterminé, en réponse à n'importe quel traitement sylvicole arbitraire.* Deux des fonctions de transition ont été calculées en utilisant l'approche différence algébrique généralisée (GADA), la troisième a été dérivée de l'approche différence algébrique (ADA). Toutes les fonctions ont été ajustées en utilisant simultanément une régression itérative sans lien apparent et une méthode basée sur l'invariance de l'âge. L'influence des éclaircies sur la croissance de la surface terrière a été inclue en ajustant différentes fonctions de transition pour les peuplements éclaircis et les peuplements non éclaircis.* Le modèle général fournit des prédictions satisfaisantes pour des intervalles de temps jusqu'à 20 ans. Le nouveau modèle est robuste et sa structure relativement simple fait qu'il est convient pour l'analyse économique et l'aide à la décision.

Summary We investigate the performance of domestic and international bond and equity portfolios of Swiss pension funds and investment foundations over the period of 1996 to 2006. Our sample consists of 73 pension funds and 13 investment foundations with total assets of more than CHF 200 billion. We find some indications for superior skills of security selection and timing by pension funds in international bond management even net of costs for asset management and fund administration. In contrast, we find a significant net underperformance for domestic bonds, domestic equities and international equities. For investment foundations, we find a significant net underperformance for domestic bonds and international equities, whereas for international bonds and domestic equities the null hypothesis of neither significant outperformance or underperformance cannot be rejected. Finally, we find no evidence of persistence in the performance of Swiss pension funds and investment foundations.

We investigate the relationship between pension fund governance and investment performance. For this purpose, we develop the Swiss Pension Fund Governance Index (SPGI) which is a standard metric for the governance quality of Swiss pension funds. The empirical analysis is based on a sample of 96 pension funds with total assets of more than CHF 190 billion. We find evidence for governance issues in the area organization and target setting. Our results support the widespread hypothesis of a positive relationship between pension fund governance and investment performance.

The scope of offences that qualify as illegal insider trading is rather narrow in Switzerland compared to other countries. Therefore we investigate abnormal returns associated with management transactions in the Swiss stock market. We find that abnormal returns of insiders are concentrated on small firms. Trading volume affects the magnitude of abnormal returns. Evidence for the stealth trading hypothesis in the Swiss stock market is found. Furthermore, our results show that clustered transactions do not reflect stronger insider beliefs. We find no evidence for insiders exploiting news announcements. Finally, only outsiders who mimic small-volume transactions of insiders can earn abnormal returns.

Nitrous oxide fluxes were measured at the Lägeren CarboEurope IP flux site over the multi-species mixed forest dominated by European beech and Norway spruce. Measurements were carried out during a four-week period in October–November 2005 during leaf senescence. Fluxes were measured with a standard ultrasonic anemometer in combination with a quantum cascade laser absorption spectrometer that measured N2O, CO2, and H2O mixing ratios simultaneously at 5 Hz time resolution. To distinguish insignificant fluxes from significant ones it is proposed to use a new approach based on the significance of the correlation coefficient between vertical wind speed and mixing ratio fluctuations. This procedure eliminated roughly 56% of our half-hourly fluxes. Based on the remaining, quality checked N2O fluxes we quantified the mean efflux at 0.8±0.4 μmol m−2 h−1 (mean ± standard error). Most of the contribution to the N2O flux occurred during a 6.5-h period starting 4.5 h before each precipitation event. No relation with precipitation amount could be found. Visibility data representing fog density and duration at the site indicate that wetting of the canopy may have as strong an effect on N2O effluxes as does below-ground microbial activity. It is speculated that above-ground N2O production from the senescing leaves at high moisture (fog, drizzle, onset of precipitation event) may be responsible for part of the measured flux., Biogeosciences, 4 (5), ISSN:1726-4170

Le remplacement d'une foret de feuillus par une monoculture d'Epiceas nous a incites a realiser la presente etude. Nos recherches concernent l'influence des differentes densites de tiges d'Epiceas sur la diversite et la productivite des macromycetes. Nous avons egalement etendu notre etude a deux placettes de la foret de feuillus restee intacte afin d'evaluer l'effet de la substitution. Les interventions sylvicoles mises en oeuvre pour le remplacement de la foret de feuillus par une pessiere de substitution sont decrites. Pendant les annees 2000 a 2003, nous avons dresse un inventaire hebdomadaire des macromycetes, de mai a novembre, sur une surface totale de 3 ooo m 2 . Les resultats demontrent l'excellente diversite et la bonne productivite fongiques des pessieres de substitution. La moyenne densite de tiges d'Epiceas est la plus riche et la plus productive des trois densites etudiees. Le nombre d'especes de champignons mycorhi2iens et saprohumicoles est pratiquement identique dans les deux types de peuplements. Par contre, les saproxylophages sont plus nombreux sous les Epiceas et la biomasse des champignons comestibles est nettement plus elevee dans les placettes de feuillus. Les macromycetes ectomycorhiziens communs aux Epiceas et aux feuillus, survivants de l'ancienne foret, peuvent etre consideres comme des colonisateurs potentiels des racines des Epiceas de la pessiere de substitution. Le lien entre des facteurs meteorologiques et la grande variation temporelle de la fructification des champignons observee est sommairement evoque.

Swiss pension funds have to guarantee a minimum return on the mandatory pension capital on a yearly basis. To be able to pay out the guaranteed rate with 100% certainty, financial theory suggests to follow a pro-cyclical dynamic investment strategy. In reality, Swiss pension funds have followed static investment strategies. In contrast to dynamic strategies, static investment strategies are not influenced by the current risk-taking capacity of the fund. In this study, we analyze four different dynamic strategies and compare them with a static buy-and-hold strategy. The dynamic strategies analyzed are a classic portfolio insurance with call options, two CPPI-type strategies and a straddle-like investment product called Reverso. The assessment of the dynamic investment strategies is based on a Monte Carlo simulation for a hypothetical pension fund. We apply expected maximum shortfall as risk criterion and expected growth rate of funding ratio as reward criterion. We show in this study that dynamic strategies can be an attractive alternative to a static investment strategy in some circumstances. The analyzed dynamic investment strategies have the potential to offer a more attractive risk-return spectrum than a static buy-and-hold strategy for the risk and return measures used in this study. For any acceptable level of risk, there is a dynamic strategy that yields a higher expected growth rate of funding ratio. However, dynamic strategies should not be seen as panacea for the issues faced by Swiss pension funds as other factors, such as transaction costs, need to be taken into account when choosing an investment strategy.

European Journal of Forest Research, 125 (1), ISSN:1612-4677, ISSN:1612-4669