Dr. Leo Bont

• Forest planning is becoming ever more important in Switzerland because of the growing demands on forests and the effects of climate change.
• Advances in digitalisation, remote sensing and mathematically-based decision-making systems are enhancing the basis for long-term planning of sustainable, economic and ecological forest management.
• The global threat to forests from deforestation, particularly in agricultural production areas, and from illegal logging is leading to stricter legal regulations on the trade in raw materials and products associated with deforestation in the EU, the US, Australia, Japan and also in Switzerland.

• In Svizzera, la pianificazione forestale sta diventando sempre più importante a causa delle maggiori esigenze e aspettative legate al bosco e delle conseguenze del cambiamento climatico.
• I progressi della digitalizzazione e del telerilevamento come anche i sistemi decisionali basati su principi matematici offrono un valido supporto nella programmazione di lungo periodo al fine di rendere la gestione forestale sostenibile, economica ed ecologica.
• La minaccia globale per le foreste derivante da dissodamenti, soprattutto per ricavare zone agricole, e dal disboscamento illegale, portano nell'UE, negli Stati Uniti, in Australia, in Giappone e anche in Svizzera ad un inasprimento delle disposizioni legislative sul commercio di materie prime e di prodotti associati alla deforestazione.

• La planification forestière en Suisse prend de plus en plus d'importance en raison des exigences accrues envers la forêt et des effets des changements climatiques.
• Les progrès de la numérisation et de la télédétection et des systèmes décisionnels mathématiques permettent d'optimiser les bases de planification à
long terme d'une économie forestière durable, économique et écologique.
• La menace que les défrichements, surtout au profit de terres agricoles, et l'abattage illégal d'arbres font peser sur les forêts dans le monde ont amené l'Union européenne, les États-Unis, l'Australie, le Japon et la Suisse à renforcer la réglementation légale du commerce des matières premières et produits liés à la déforestation.

• Der Wald erbringt eine Vielzahl von Leistungen, die der Sicherheit und dem Wohlergehen der Bevölkerung dienen. Er erfüllt die Schutz-, Nutz- und Wohlfahrtsfunktionen.
• Die Erbringung von Waldleistungen verursacht Kosten, die bisher nur zum Teil gedeckt waren. Um sie abzugelten, können die Leistungen mithilfe von Indikatoren und expertenbasierten Bewertungssystemen in Wert gesetzt und monetarisiert werden.
• Die Nachfrage nach Waldleistungen wird angesichts des zunehmenden im Wald stattfindenden Freizeitverhaltens weiter steigen. Dabei sind auch Zielkonflikte bei der Bereitstellung verschiedener Waldleistungen zu erwarten.

Woody biomass from sustainable sources, from suitable assortments, and used with state-of-the-art combustion technologies is a renewable and environmentally friendly energy source. In combination with other renewable energies, such as solar, wind or hydropower, wood is an important component of an energy system that is no longer or only minimally based on fossil fuels. Technologies for converting woody biomass into energy are well understood, with various pathways available. However, a key challenge lies in precisely assessing the sustainable forest biomass or fuelwood availability, which has been the focus of numerous studies at the global, national and regional levels. In this study, we aim to assess Switzerland's realistic, sustainable forest fuelwood potential, focusing on local precision and spatially explicit estimation. This novel method is based on three key pillars: [1] initial stock volume estimation, [2] harvest intensity estimation, and [3] energy content estimation. For model fitting we used data from Switzerland's National Forest Inventory, which tracks changes in stock and harvest over time through 5 repeated surveys of more than 6000 plots, combined with remote sensing data. To verify the approach, we calculated a conservative fuelwood use scenario in which twigs and bark remain in the forest and assortments are fed into cascading use: in total, a yearly sustainable potential of around 19 PJ of dry wood is available. In many Swiss cantons, the sustainable fuelwood potential has already been reached, reflecting current forest management practices.

Die prognostizierte Zunahme von extremen Störungsereignissen wie Borkenkäferbefall und Windwurf im Kontext des Klimawandels stellt die Schweizer Waldbewirtschaftung vor grosse Herausforderungen. Besonders betroffen sind fichtendominierte Gebirgswälder, die grossflächig verbreitet sind und häufig eine zentrale Schutzfunktion gegenüber Naturgefahren erfüllen. Die WSL erarbeitet zusammen mit der Praxis Grundlagen für die Priorisierung der Bewirtschaftung dieser Wälder unter dem Einfluss von extremen Störungen. Dazu werden räumliche Daten zu Waldstruktur, Standort, Störungsanfälligkeit und Naturgefahren auf Landschaftsebene mit waldbaulichen, planerischen und ökonomischen Aspekten verknüpft und in einem interaktiven Dashboard visualisiert. Dieser inter- und transdisziplinäre Ansatz wird hier anhand eines Fallbeispiels im Schilstal (Kanton St. Gallen) vorgestellt.

Management of spruce-dominated mountain forests in the context of extreme disturbances
The predicted increase in extreme disturbance events, such as windthrow and bark beetle infestations in the context of climate change poses major challenges for Swiss forest management. Mountain forests dominated by Norway spruce, which are both widespread and often fulfil an essential protective function against natural hazards, are particularly at risk. In response, the WSL is collaborating with practitioners to develop a framework for prioritising the management of these forests under the influence of extreme disturbances. This involves integrating spatial data on forest structure, site conditions, susceptibility to disturbance and natural hazards at the landscape level with silvicultural, planning and economic aspects. These insights are visualised through an interactive dashboard. This interand transdisciplinary approach is presented here with a case study from the Schilstal in the Canton of St. Gallen.

Close-to-nature forestry (CNF) is considered an effective strategy to adapt forests to climate change while sustaining ecosystem services and biodiversity (BES). However, for forest management it remains unclear whether current CNF strategies sufficiently reduce forests' predisposition to climate-change-induced shifts in disturbance regimes. To address this increasing complexity, we introduce the integration of a climate-sensitive forest gap model with assessments of predisposition to fire, bark beetle, and windthrow disturbances, as well as BES provision. We conducted simulations for a forest enterprise in the Central Swiss Alps, covering a large elevation gradient, under three climate scenarios (historical, SSP2–4.5, and SSP5–8.5). The simulations additionally considered six management strategies, including CNF variants with different management intensities and climate-adapted approaches. Our results indicate that climate change will dynamically alter disturbance predisposition across elevation gradients. Site-related predisposition to fire and bark beetle infestation generally increased under climate change, while stand-related predisposition to all disturbances varied with climate scenario and elevation. Under moderate warming (SSP2–4.5), stand-related predisposition to fire and windthrow increased across all elevations. In contrast, under severe warming (SSP5–8.5), long-term reductions in stand-related predisposition to fire, bark beetle infestation, and windthrow occurred at lower elevations due to climate-change-induced shifts in forest dynamics, while predisposition increased at higher elevations with improved growing conditions. Our results further show that increasing management intensity generally reduces stand-related disturbance predisposition but focusing purely on disturbance mitigation can also lead to trade-offs, such as reduced BES provision. We conclude that climate-adapted forest management must account for both stand-related and site-related predisposition to prioritize disturbance-prone 'hotspots', especially in areas of high BES value. Proactively reducing disturbance predisposition may involve trade-offs regarding BES provision but may be crucial to avoid potential BES losses from severe disturbances. As climate change may alter trade-offs between BES and disturbance mitigation, we underscore the need for decision support systems in long-term forest planning to account for conflicting management objectives.

Strategic long-term planning of mountain forests in the European Alps requires a balancing act between sustaining forest biodiversity and ecosystem services (BES) and mitigating disturbance risks, particularly under climate change. Multi-criteria decision support systems (DSSs) address this challenge by integrating climate-sensitive forest modelling into frameworks for the evaluation of BES provision under simulated climate and management trajectories. Recent developments incorporate assessments of disturbance predisposition into DSSs, accounting for risks from bark beetle infestations and windthrow. These DSS frameworks have proven flexible applicability across various forest models, spatial scales, forest types, and environmental conditions. However, climate-change-induced transitions of disturbance regimes require adaptations of existing DSS frameworks by accounting for emerging disturbance agents, such as forest fires. Here, we introduce the integration of a fire predisposition assessment system (PAS) into a DSS, incorporating factors such as topography, climatic conditions, wildland–urban interface, and stand structural characteristics. Particularly in the context of long-term planning in mountain forests, the expanded DSS could enable the identification of conflicting forest management objectives related to BES provision and disturbance mitigation efforts under climate change, leading to more informed management decisions.

• A predisposition assessment system for assessing multiple predisposing factors of forest fires is presented.
• The fire PAS enables an integrated evaluation with disturbance predisposition to bark beetle infestations and windthrow, as well as BES provision.
• The modular structure of the fire PAS enables adaptation and application to various spatial scales, as well as integration with different forest models.

Ce manuel s’adresse aux utilisateurs du plugin QGIS Seilaplan. Il sert, avec les tutoriels sur le site web seilaplan.wsl.ch, d’introduction à l’utilisation de Seilaplan. Le premier chapitre est une brève introduction au plugin et à l’histoire de sa création. Les instructions d’installation du chapitre 2 et le guide de démarrage rapide du chapitre 3 vous aideront à faire vos premiers pas. Le chapitre 4 présente les principales bases concernant les géodonnées. Le chapitre 5 décrit les fonctionnalités du plug-in ainsi que son utilisation. Les bases théoriques et les résultats pratiques des tests peuvent être consultés au chapitre 6. Enfin, le chapitre 7 présente une sélection d’ouvrages pertinents.
Chapitre 1 – Introduction
Chapitre 2 – Guide d’installation
Chapitre 3 – Guide de démarrage rapide
Chapitre 4 – Géodonnées
Chapitre 5 – Description du plugin
Chapitre 6 – Bases théoriques
Chapitre 7 – Bibliographie
Les chapitres sont indépendants les uns des autres et sont régulièrement mis à jour sur le site web de Seilaplan. De plus, d’autres chapitres sont en cours de planification et seront publiés sur le site web de Seilaplan. Le manuel a été élaboré dans le cadre de la 1ère journée Seilaplan du 30 août 2023 au WSL à Birmensdorf.

Properly planned skid trails form an important basis for sustainable timber production. They affect cost-effectiveness and the environmental impact of the harvesting process to a large extent. Here, we conducted an economic analysis to understand the skid trail planning process and to generate an initial model to estimate the time and costs involved. We investigated in detail how the planning process of skid trails is carried out in practice, what time is required for the planning work, and what factors influence its performance. Through an online survey conducted in 2022, we asked practitioners in Germany and Switzerland about their time and effort required for the planning process and the determining factors, such as the planning method and the terrain and stand conditions. Based on this survey, we calculated statistical indicators of time consumption, considered possible rationalization options, and developed an initial estimation model. The effort required to identify and evaluate skid trails planned for distances of 20 to 40 m amounts to around 3 to 4 hours of productive working time per hectare, with deviations expected depending on the specific situation in the forest. The costs corresponding to this investment amount to less than one euro per cubic meter of harvested timber, depending primarily on the extent of wood use. Our in-depth insight into the planning process enables its economic evaluation and the development of improvements.

Close-to-nature forestry (CNF) has a long tradition in European Alpine forest management, playing a crucial role in ensuring the continuous provision of biodiversity and forest ecosystem services, including protection against natural hazards. However, climate change is causing huge uncertainties about the future applicability of CNF in the Alpine region. The question arises as to whether current CNF practices are still suitable for adapting forests to climate change impacts while also meeting the increasing societal demands regarding Alpine forests, including their potential contribution to climate change mitigation. To answer this question, we simulated forest development using the ForClim forest model at two Alpine study sites, together representing a large biogeographic gradient from high-elevation inner Alpine forests (Switzerland) to lower-elevation south-eastern Alpine forests (Slovenia). The simulations considered three climate scenarios (historical climate, SSP2-4.5 and SSP5-8.5) and six alternative management strategies, including both current CNF management practices and climate-adapted versions. Using an indicator based multi-criteria decision analysis framework, we assessed the joint impacts of climate and management on biodiversity and key ecosystem services of the investigated regions, including carbon sequestration (CS) inside and outside the forest ecosystem boundary. The joint effects of climate change and CNF varied, both among and within the study sites along the biogeographical gradient. While CS was more resistant to climate change under current CNF at the south-eastern Alpine site, it was more sensitive at the inner Alpine site, where CS potentials decreased at lower elevations. This adverse effect could be partly mitigated by fostering the use of climate-adapted tree species. However, current CNF and adaptations of it did not meet multiple management objectives equally well: while protection from gravitation hazards and timber production also benefited from this silvicultural practice, biodiversity benefited from CNF variants with low-intensity or no management. In conclusion, CNF has a high potential to continue fulfilling its crucial role in European Alpine forests. A differentiated approach will be needed in the future, however, to identify forest stands where adaptive measures are required, especially at sites particularly vulnerable to climate change. In combination with less intensively managed or unmanaged areas, CNF provides a management portfolio that will help European Alpine forests to meet the demands of future society.

Je nach Erntemethode beeinflusst eine Veränderung der Personalkosten um 1 % die Erntekosten um 0,33-0,77 %. Erwartungsgemäss ist der Einfluss größer bei Systemen mit einem hohen Anteil an motormanueller Holzerei und bei seilgestützten Verfahren. Eine Änderung der Personalkosten um +30 % wirkt sich um 5 bis 15 Prozentpunkte auf den Anteil der Waldflächen aus, für die eine Holzernte wirtschaftlich machbar ist. Eine konsequente Anwendung des Best-Verfahrens hat ähnliche wirtschaftliche Auswirkungen, als wenn Personalkosten um 15 bis 30 % gesenkt würden. Das deutet darauf hin, dass die Effizienz der Holzernte bei gleichen Löhnen durch weitere Mechanisierung gesteigert werden könnte oder bei konsequenter Anwendung des Bestverfahrens, bei gleicher Effizienz, die Löhne erhöht werden könnten.

Mountain forests provide not only wood as a raw material but also numerous ecosystem services, such as protection against natural hazards, recreation and carbon sequestration, and they are important hosts for biodiversity. To manage these forests efficiently and in a target-oriented manner, both forest management planning and efficient harvesting operations are required. However, in most cases these two aspects are handled independently from each other. To link planning with forest operations, it is essential to divide forests into smaller areas with characteristics that are as homogeneous as possible, so-called forest management units (FMUs). The goal is that each FMU has self-contained fine access (e.g. skid roads, cable roads), and that the FMUs can be managed and planned independently. The aim of this study was to develop a spatial optimisation model that automatically identifies FMUs. The optimisation has three goals: [I] FMUs should be as compact as possible (spatially contiguous as the best case); [II] forest management should be technically and operationally coordinated within an FMU; and [III] FMUs should be as homogeneous as possible, for example regarding site properties, ecosystem service provided, and administrative affiliation. Results showed that our presented spatial optimisation model is a capable method for automatically identifying FMUs. The approach used to set up the model based on a p-median problem formulation (mixed integer linear programming) led to clearly comprehensible solutions that can be achieved in a reasonable computation time. Three solving strategies for successful computation implementation are described. Although the raw results must be reviewed by experts, they facilitate the planning process. More scenarios can be evaluated compared with the classical manual planning approach, ultimately leading to higher-quality solutions.

Efficient forest operations are essential for forest enterprises, who provide wood and numerous ecosystem services for the society. Important factors influencing the efficiency of forest operations, and thus the harvesting costs, are the level of mechanization, the harvesting method applied, the forest road network, and the training of the labourers. The cost of labour, i.e. salaries, is another important driver of harvesting costs. However, its effect on and relative importance for overall harvesting costs is poorly described in the scientific literature. Thus, this study aims to analyse the influence of labour costs in more detail, especially on the country-wide wood harvesting potentials. In addition, we aimed to cross-compare the effect of labour costs with the effect of switching to a more efficient harvesting method. For this purpose, we calculated timber harvesting costs with varying salaries for all sample plots of the Swiss National Forest Inventory (NFI) for both, the currently applied harvesting method recorded in the NFI, and the potential best suitable harvesting method. A 1% change in labour costs affects harvesting costs by 0.33–0.77%, depending on the harvesting method applied. The influence is larger for systems that involve a large share of motor-manual work and for cable-based methods. Changing labour costs by ± 30% affects the number of plots for which timber harvesting is economically feasible, by 5 to 15 percent points. The effect of switching from the current to the best suitable harvesting method is comparable to that of reducing labour costs by 15–30%. These results indicate that the efficiency of wood harvesting can be increased with further mechanization and does not require cutting salaries of forestry personnel. In that, our results may inform forestry planning and policy making at regional to national level.

Ein gut geführter Forstbetrieb stellt bereits während der Planung effiziente Arbeitsabläufe sicher. Vor allem in topographisch anspruchsvollem Gelände oder im stufigen Wald ist es jedoch nicht immer einfach, die operationelle Ausführung auf der Fläche mit der waldbaulichen Planung und Kontrolle zu verbinden. Mit der automatisierten Ausscheidung von Bewirtschaftungseinheiten haben Planende eine leistungsfähige Methode zur Hand die individuellen Bedürfnisse des Forstbetriebs in einer optimalen Flächeneinteilung abzubilden.

Purpose of the review the aim of the review was to better understand the impacts of the dominant harvesting systems in Europe, namely harvester-forwarder (HFW), chainsaw-skidder (CSK), and chainsaw-cable yarder (CCY). Furthermore, we aimed to learn how the impact categories environment, economy, ergonomics, people and society, and quality optimization are related to the European biogeographical regions Boreal, Continental, Alpine, and Mediterranean forests. Based on this, key drivers for the future development of forest operations were identified. It was specifically not the aim to develop models through the outcome of this study.
Recent findings HFW harvesting systems dominate in Boreal (99%) and Continental forests (72%). In Alpine forests the most relevant, even when not dominant, harvesting system is CCY (47%). CSK harvesting systems are applied in all biogeographical regions, with a focus on Mediterranean (70%), Alpine (50%) and Continental (22%) forests. Major drivers for harvesting system development were identified: (i) increased environmental constraints, (ii) increased complexity of harvesting caused by an increasing area of mixed-forest stands, (iii) increased resource efficiency fostered by a growing demand for wood products, (iv) a reduced available work force resulting from heightened competition for skilled worker and an aging population, and (v) more transparent work and material flows through the introduction of digitalization.
Summary a literature review from 110 journal articles and 975 datasets from four biogeographical regions in Europe, specifically from Estonia, Germany, Spain and Switzerland was performed. Most of the reviewed papers included information about economic or environmental impacts, while ergonomics, quality optimization and societal aspects were less in focus. The impacts from the HFW, CSK and CCY harvesting systems were evaluated against regional conditions. Unfortunately, a common understanding of harvesting system evaluation is missing, which limits the comparability of results between different regions.

Dieses Handbuch richtet sich an die AnwenderInnen des QGIS-Plugins Seilaplan. Es dient zusammen mit den Tutorials auf der Seilaplan-Webseite seilaplan.wsl.ch als Einstieg in die Benutzung von Seilaplan. Das erste Kapitel ist eine kurze Einführung ins Plugin und seine Entstehungsgeschichte. Die Installationsanleitung in Kapitel 2 und die Kurzanleitung in Kapitel 3 helfen bei den ersten Schritten. In Kapitel 4 werden die wichtigsten Grundlagen betreffend Geodaten vermittelt. Kapitel 5 beschreibt die Funktionalitäten des Plugins sowie dessen Anwendung. Die theoretischen Grundlagen und praktischen Erkenntnisse aus den Testungen können im Kapitel 6 nachgelesen werden. Abschliessend ist im Kapitel 7 eine Auswahl relevanter Literatur zu finden.
Kapitel 1 – Einleitung
Kapitel 2 – Installationsanleitung
Kapitel 3 – Kurzanleitung
Kapitel 4 – Geodaten
Kapitel 5 – Beschreibung Plugin
Kapitel 6 – Theoretische Grundlagen
Kapitel 7 – Literatur
Die Kapitel sind unabhängig voneinander und werden auf der Seilaplan-Webseite regelmässig aktualisiert. Zudem sind weitere Kapitel in Planung, welche auf der Seilaplan-Webseite publiziert werden. Das Handbuch ist im Rahmen der 1. Seilaplan-Tagung vom 30. August 2023 an der WSL in Birmensdorf entstanden.