Publications de l'IFN
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Allgaier Leuch B., Braun S., Meusburger K., Tresch S., Reinhardt M., Waldner P., Wolf O. (2025) Acqua potabile. In A. Strauss & C. Fischer (Eds.), Rapporto forestale 2025. Evoluzione, stato e utilizzazione del bosco svizzero. Berna; Birmensdorf: Ufficio federale dell'ambiente (UFAM); Istituto federale di ricerca per la foresta, la neve e il paesaggio (WSL). 102-103.
• Le acque sotterranee provenienti dalle aree forestali sono solitamente di qualità tale da poter essere immesse nella rete dell'acqua potabile senza ulteriori trattamenti.
• Il dilavamento dei nitrati dal suolo forestale nell'ultimo decennio non ha subito variazioni. Tuttavia, localmente può essere elevato e indicare un eccessivo carico di azoto.
• Per abbattere le concentrazioni di nitrato nell'acqua di falda e quindi in quella potabile, occorre ridurre gli apporti di azoto atmosferico. Le misure selvicolturali che rafforzano la resilienza dei boschi possono anche ridurre il rischio di dilavamento dei nitrati in seguito a perturbazioni. -
Allgaier Leuch B., Abegg M., Jenni R., Kunnala M. (2025) Age and stand structure. In A. Strauss & C. Fischer (Eds.), Forest Report 2025. Development, condition and use of Swiss forests. Bern; Birmensdorf: Federal Office for the Environment FOEN; Swiss Federal Institute for Forest, Snow and Landscape Research WSL. 34-36.
• The proportion of old stands and large-diameter trees has risen in the past decade, which is good news for biodiversity. Conversely, there is an increasing lack of young stands and sufficient regeneration, which could negatively impact forests’ protective and wood production functions.
• From an economic perspective, the age structure of Swiss forests is too old. However, from an ecological point of view, more old stands and large-diameter trees are needed. That said, stand structures are often diverse.
• Climate change calls for a further increase in structural diversity, as richly structured forests with sufficient regeneration are less vulnerable and can resume their services more quickly after disturbances. -
Allgaier Leuch B., Abegg M., Jenni R., Kunnala M. (2025) Altersaufbau und Bestandesstruktur. In A. Strauss & C. Fischer (Eds.), Waldbericht 2025. Entwicklung, Zustand und Nutzung des Schweizer Waldes. Bern; Birmensdorf: Bundesamt für Umwelt BAFU; Eidg. Forschungsanstalt für Wald Schnee und Landschaft WSL. 34-36.
• Der Anteil der alten Bestände und dicken Bäume hat in der letzten Dekade zugenommen, was für die Biodiversität positiv ist. Dagegen mangelt es zunehmend an jungen Beständen sowie ausreichender Verjüngung. Dies könnte sich negativ auf die Schutz- und Holzproduktionsfunktionen des Waldes auswirken.
• Aus ökonomischer Sicht ist der Schweizer Wald in seinem Altersaufbau zu alt. Aus ökologischer Sicht dagegen fehlen alte Bestände und dicke Bäume. Die Bestandesstrukturen aber sind oft vielfältig.
• Es gilt, angesichts des Klimawandels die strukturelle Vielfalt weiter zu erhöhen, denn reich strukturierte Wälder mit genügender Verjüngung sind weniger anfällig und können nach Störungen die Leistungen schneller wieder erbringen. -
Allgaier Leuch B., Bebi P., Lange B., Losey S. (2025) Bosco di protezione. In A. Strauss & C. Fischer (Eds.), Rapporto forestale 2025. Evoluzione, stato e utilizzazione del bosco svizzero. Berna; Birmensdorf: Ufficio federale dell'ambiente (UFAM); Istituto federale di ricerca per la foresta, la neve e il paesaggio (WSL). 97-103.
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Allgaier Leuch B., Abegg M., Jenni R., Kunnala M. (2025) Distribuzione dell'età e struttura dei popolamenti. In A. Strauss & C. Fischer (Eds.), Rapporto forestale 2025. Evoluzione, stato e utilizzazione del bosco svizzero. Berna; Birmensdorf: Ufficio federale dell'ambiente (UFAM); Istituto federale di ricerca per la foresta, la neve e il paesaggio (WSL). 34-36.
• Nell'ultimo decennio, la quota di popolamenti vecchi e di alberi grandi è aumentata, con ripercussioni positive sulla biodiversità. Mancano invece sempre più spesso popolamenti giovani e una sufficiente rinnovazione. Questo fenomeno potrebbe avere un impatto negativo sulle funzioni protettive e sulla produzione del legno.
• Da un punto di vista economico, la struttura del bosco svizzero è troppo vecchia, mentre sul piano ecologico mancano popolamenti vecchi e alberi grandi. I popolamenti presentano però spesso una struttura diversificata.
• Alla luce del cambiamento climatico, occorre incrementare ulteriormente la diversità strutturale dei boschi perché questo aspetto, unito a una sufficiente rinnovazione, li rende meno vulnerabili e in grado di riprendersi più rapidamente in seguito a perturbazioni. -
Allgaier Leuch B., Braun S., Meusburger K., Tresch S., Reinhardt M., Waldner P., Wolf O. (2025) Drinking water. In A. Strauss & C. Fischer (Eds.), Forest Report 2025. Development, condition and use of Swiss forests. Bern; Birmensdorf: Federal Office for the Environment FOEN; Swiss Federal Institute for Forest, Snow and Landscape Research WSL. 102-103.
• The groundwater from forest areas is usually of such good quality that it can be fed into the drinking water network without further treatment.
• Levels of nitrate leaching from forest soils have hardly changed in the past decade. However, they can be high in some localities, indicating an excessive nitrogen load.
• In order to lower nitrate concentrations in seepage water and thus in drinking water from forest areas, nitrogen deposition from the air must be reduced. Silvicultural measures that strengthen forests’ resilience can also reduce the risk of nitrate leaching after disturbance events. -
Allgaier Leuch B., Braun S., Meusburger K., Tresch S., Reinhardt M., Waldner P., Wolf O. (2025) Eau potable. In A. Strauss & C. Fischer (Eds.), Rapport forestier 2025. Évolution, état et utilisation de la forêt suisse. Berne; Birmensdorf: Office fédéral de l'environnement OFEV; Institut fédéral de recherches sur la forêt, la neige et le paysage WSL. 102-103.
• Les eaux souterraines des zones forestières sont en général de si bonne qualité qu'elles peuvent être injectées sans traitement dans le réseau d'eau potable.
• Le lessivage des nitrates des sols forestiers n'a guère évolué durant la dernière décennie. Il peut être localement élevé, signalant une charge excessive d'azote.
• Pour abaisser la concentration de nitrates dans les eaux d'infiltration et donc dans l'eau potable de zones forestières, les dépôts atmosphériques azotés doivent être réduits. Des mesures sylvicoles renforçant la résilience de la forêt permettent de limiter le risque de lessivage de nitrates après des perturbations. -
Allgaier Leuch B., Bebi P., Lange B., Losey S. (2025) Forêt protectrice. In A. Strauss & C. Fischer (Eds.), Rapport forestier 2025. Évolution, état et utilisation de la forêt suisse. Berne; Birmensdorf: Office fédéral de l'environnement OFEV; Institut fédéral de recherches sur la forêt, la neige et le paysage WSL. 97-103.
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Allgaier Leuch B., Bebi P., Lange B., Losey S. (2025) Protective forest. In A. Strauss & C. Fischer (Eds.), Forest Report 2025. Development, condition and use of Swiss forests. Bern; Birmensdorf: Federal Office for the Environment FOEN; Swiss Federal Institute for Forest, Snow and Landscape Research WSL. 97-103.
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Allgaier Leuch B., Bebi P., Lange B., Losey S. (2025) Schutzwald. In A. Strauss & C. Fischer (Eds.), Waldbericht 2025. Entwicklung, Zustand und Nutzung des Schweizer Waldes. Bern; Birmensdorf: Bundesamt für Umwelt BAFU; Eidg. Forschungsanstalt für Wald Schnee und Landschaft WSL. 97-103.
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Allgaier Leuch B., Abegg M., Jenni R., Kunnala M. (2025) Structure d'âge et structure des peuplements. In A. Strauss & C. Fischer (Eds.), Rapport forestier 2025. Évolution, état et utilisation de la forêt suisse. Berne; Birmensdorf: Office fédéral de l'environnement OFEV; Institut fédéral de recherches sur la forêt, la neige et le paysage WSL. 34-36.
• La part de peuplements âgés et de gros arbres a augmenté durant la dernière décennie, ce qui est favorable à la biodiversité. En revanche, les jeunes peuplements et la régénération font de plus en plus défaut. Les fonctions de protection et de production de bois de la forêt pourraient en souffrir.
• Du point de vue économique, la forêt suisse est trop vieille dans sa structure d'âge. Du point de vue écologique, elle manque au contraire de vieux peuplements et de gros arbres. Cependant, les structures des peuplements sont souvent variées.
• Au vu des changements climatiques, il importe d'accroître encore cette diversité, car des forêts très structurées avec une régénération suffisante sont
moins vulnérables et plus vite capables de fournir à nouveau leurs prestations après des perturbations. -
Allgaier Leuch B., Braun S., Meusburger K., Tresch S., Reinhardt M., Waldner P., Wolf O. (2025) Trinkwasser. In A. Strauss & C. Fischer (Eds.), Waldbericht 2025. Entwicklung, Zustand und Nutzung des Schweizer Waldes. Bern; Birmensdorf: Bundesamt für Umwelt BAFU; Eidg. Forschungsanstalt für Wald Schnee und Landschaft WSL. 102-103.
• Das Grundwasser aus Waldgebieten ist meist von so guter Qualität, dass es ohne weitere Aufbereitung ins Trinkwassernetz eingespeist werden kann.
• Die Nitratauswaschung aus den Waldböden hat sich in der letzten Dekade kaum verändert. Sie kann jedoch lokal hoch sein und weist auf eine übermässige Stickstoffbelastung hin.
• Um die Nitratkonzentrationen im Sickerwasser und damit im Trinkwasser aus Waldgebieten zu senken, ist die Reduktion der Stickstoffeinträge aus der Luft erforderlich. Mit waldbaulichen Massnahmen, die die Resilienz der Wälder stärken, lässt sich zudem das Risiko der Nitratauswaschung nach Störungsereignissen verringern. -
Bebi P., Lange B., Allgaier Leuch B., Losey S. (2025) Protection against natural hazards. In A. Strauss & C. Fischer (Eds.), Forest Report 2025. Development, condition and use of Swiss forests. Bern; Birmensdorf: Federal Office for the Environment FOEN; Swiss Federal Institute for Forest, Snow and Landscape Research WSL. 98-101.
• The proportion of protective forest with little regeneration has risen again in the past decade as protective forests have become denser and browsing by wild ungulates has remained high.
• According to the National Forest Inventory, 44% of Swiss forest is classed as protective forest, meaning that it protects people and physical assets from natural hazards such as landslides, avalanches, rockfall or debris flows.
• Increasing disturbances due to climate change will reduce the protective effect of forests in some areas. In order to minimise such adverse effects, the resilience of protective forests must be enhanced. -
Bebi P., Lange B., Allgaier Leuch B., Losey S. (2025) Protection contre les dangers naturels. In A. Strauss & C. Fischer (Eds.), Rapport forestier 2025. Évolution, état et utilisation de la forêt suisse. Berne; Birmensdorf: Office fédéral de l'environnement OFEV; Institut fédéral de recherches sur la forêt, la neige et le paysage WSL. 98-101.
• La part de forêts protectrices avec peu de régénération a encore augmenté durant la dernière décennie du fait de leur densification et d'un abroutissement
toujours intense des ongulés.
• Selon l'Inventaire forestier national (IFN), 44 % des forêts suisses sont des forêts protectrices. Elles protègent la population et les infrastructures contre les dangers naturels tels que glissements de terrain, avalanches, chutes de pierres ou laves torrentielles.
• Par endroits, les perturbations accrues causées par les changements climatiques affaibliront leur effet protecteur. Pour limiter au maximum leur impact, la résilience de ces forêts doit être augmentée. -
Bebi P., Lange B., Allgaier Leuch B., Losey S. (2025) Protezione dai pericoli naturali. In A. Strauss & C. Fischer (Eds.), Rapporto forestale 2025. Evoluzione, stato e utilizzazione del bosco svizzero. Berna; Birmensdorf: Ufficio federale dell'ambiente (UFAM); Istituto federale di ricerca per la foresta, la neve e il paesaggio (WSL). 98-101.
• Nell'ultimo decennio, i boschi di protezione con scarsa rinnovazione sono nuovamente aumentati perché sono diventati più fitti e il brucamento da parte degli ungulati è rimasto a un livello elevato.
• Secondo l'Inventario forestale nazionale il 44 per cento della superficie forestale è costituita da boschi di protezione che proteggono le persone e i beni materiali da pericoli naturali come scivolamenti, valanghe, cadute di massi o colate di detriti.
• Il crescente impatto del cambiamento climatico ridurrà in parte l'azione protettiva dei boschi. Per contenere il
più possibile questi effetti negativi, occorre incrementare la resilienza dei boschi di protezione. -
Bebi P., Lange B., Allgaier Leuch B., Losey S. (2025) Schutz vor Naturgefahren. In A. Strauss & C. Fischer (Eds.), Waldbericht 2025. Entwicklung, Zustand und Nutzung des Schweizer Waldes. Bern; Birmensdorf: Bundesamt für Umwelt BAFU; Eidg. Forschungsanstalt für Wald Schnee und Landschaft WSL. 98-101.
• In der letzten Dekade hat der Anteil des Schutzwaldes mit wenig Verjüngung erneut zugenommen, weil die Schutzwälder dichter geworden sind und der Verbiss durch Schalenwild auf hohem Niveau verharrte.
• 44 % des Schweizer Waldes sind gemäss Landesforstinventar Schutzwald. Er schützt Menschen und Sachwerte vor Naturgefahren wie Rutschungen, Lawinen, Steinschlag oder Murgängen.
• Die zunehmenden Störungen aufgrund des Klimawandels werden die Schutzwirkung des Waldes gebietsweise mindern. Um solche Beeinträchtigungen möglichst gering zu halten, muss die Resilienz der Schutzwälder erhöht werden. -
Bolgè R., Cioldi F., Maineri C. (2025) Superficie forestale. In A. Strauss & C. Fischer (Eds.), Rapporto forestale 2025. Evoluzione, stato e utilizzazione del bosco svizzero. Berna; Birmensdorf: Ufficio federale dell'ambiente (UFAM); Istituto federale di ricerca per la foresta, la neve e il paesaggio (WSL). 30-31.
• La superficie forestale è aumentata solo leggermente nell'ultimo decennio, e la maggior parte dell'incremento si è registrato alle altitudini più elevate, dove i boschi hanno soppiantato l'uso agricolo.
• Il bosco ricopre quasi un terzo della superficie totale della Svizzera, ovvero 1,3 milioni di ettari. Il Sud
delle Alpi ne è particolarmente ricco con una quota del 55 per cento, mentre l'Altipiano densamente popolato raggiunge circa il 24 per cento.
• Preservare l'attuale area forestale e la sua ripartizione geografica rimarrà una sfida nelle regioni caratterizzate da una spiccata concorrenza per l'utilizzo del suolo come l'Altipiano o i fondovalle. -
Bolgè R., Cioldi F., Maineri C. (2025) Surface forestière. In A. Strauss & C. Fischer (Eds.), Rapport forestier 2025. Évolution, état et utilisation de la forêt suisse. Berne; Birmensdorf: Office fédéral de l'environnement OFEV; Institut fédéral de recherches sur la forêt, la neige et le paysage WSL. 30-31.
• L'aire forestière n'a que légèrement augmenté durant la dernière décennie. Elle s’est surtout étendue en altitude, à la place de l'exploitation agricole.
• Les forêts occupent environ un tiers du territoire suisse, soit 1,3 million d'ha. Le taux de boisement est particulièrement élevé dans le sud des Alpes, où il atteint 55%. Sur le Plateau, très peuplé, il est d'environ 24%.
• La conservation de l'aire forestière et de sa répartition spatiale restera un défi dans les régions où le sol est très convoité, comme le Plateau ou en fond de vallée. -
Bolgè R., Cioldi F., Maineri C. (2025) Waldfläche. In A. Strauss & C. Fischer (Eds.), Waldbericht 2025. Entwicklung, Zustand und Nutzung des Schweizer Waldes. Bern; Birmensdorf: Bundesamt für Umwelt BAFU; Eidg. Forschungsanstalt für Wald Schnee und Landschaft WSL. 30-31.
• Die Waldfläche hat in der letzten Dekade nur noch leicht zugenommen, wobei die Zunahme zumeist in höheren Lagen stattgefunden und dort die landwirtschaftliche Nutzung abgelöst hat.
• Rund ein Drittel der Schweizer Landesfläche oder 1,3 Millionen Hektaren sind mit Wald bedeckt. Besonders stark bewaldet ist die Alpensüdseite mit einem Waldanteil von 55 %. Im dicht besiedelten Mittelland beträgt der Waldanteil rund 24 %.
• Die Erhaltung der Waldfläche und ihrer räumlichen Verteilung wird in Regionen mit ausgeprägter Landnutzungskonkurrenz wie dem Mittelland oder den Talböden eine Herausforderung bleiben. -
Bolgé R., Cioldi F., Maineri C. (2025) Forest area. In A. Strauss & C. Fischer (Eds.), Forest Report 2025. Development, condition and use of Swiss forests. Bern; Birmensdorf: Federal Office for the Environment FOEN; Swiss Federal Institute for Forest, Snow and Landscape Research WSL. 30-31.
• The forest area has increased only slightly in the past decade, mostly at higher altitudes, where it has replaced agricultural use.
• Around a third of Switzerland’s land area, or 1.3 million hectares, is covered by forest. The southern side of the Alps is particularly heavily forested, with forest cover of 55%. On the densely populated Plateau, the proportion is around 24%.
• Maintaining the forest area and its spatial distribution will remain a challenge in regions with heavy competition for land such as the Plateau and valley floors. -
Bollmann K., Stofer S., Abegg M., Thrippleton T. (2025) Artenvielfalt. In A. Strauss & C. Fischer (Eds.), Waldbericht 2025. Entwicklung, Zustand und Nutzung des Schweizer Waldes. Bern; Birmensdorf: Bundesamt für Umwelt BAFU; Eidg. Forschungsanstalt für Wald Schnee und Landschaft WSL. 74-77.
• Die Artenzusammensetzung im Schweizer Wald verändert sich. Bei der Esche und der Kastanie sind Abnahmen zu verzeichnen, eine Zunahme bei Ahorn und Arve sowie bei der durchschnittlichen Anzahl Moos- und Schneckenarten.
• Rund 40% der Tier- und Pflanzenarten der Schweiz leben im Wald. Der Anteil der im Wald lebenden Arten ist bei Flechten, Grosspilzen, Fledermäusen und Bockkäfern besonders gross.
• Der Rückgang der Esche wird negative Auswirkungen auf die mit ihr verbundenen Lebensgemeinschaften wie Flechten, Moose und Pilze haben. Ebenso werden Klimawandel, invasive Neophyten sowie atmosphärische Stickstoffeinträge die Artenzusammensetzung im Wald weiter verändern. -
Bollmann K., Stofer S., Abegg M., Thrippleton T. (2025) Diversità delle specie. In A. Strauss & C. Fischer (Eds.), Rapporto forestale 2025. Evoluzione, stato e utilizzazione del bosco svizzero. Berna; Birmensdorf: Ufficio federale dell'ambiente (UFAM); Istituto federale di ricerca per la foresta, la neve e il paesaggio (WSL). 74-77.
• La composizione delle specie nel bosco svizzero sta cambiando. Sono diminuiti il frassino e il castagno, sono aumentati l'acero e il pino cembro e in media anche il numero di muschi e lumache.
• Circa il 40 per cento delle specie animali e vegetali della Svizzera vive nel bosco, con una quota particolarmente elevata di licheni, macromiceti, pipistrelli e coleotteri.
• Il declino dei frassini avrà un impatto negativo sulle biocenosi ad esso associate, come quelle di licheni, muschi e funghi. Anche il cambiamento climatico, le neofite invasive e gli apporti di azoto atmosferico continueranno a modificare la composizione delle specie. -
Bollmann K., Stofer S., Abegg M., Thrippleton T. (2025) Diversité des espèces. In A. Strauss & C. Fischer (Eds.), Rapport forestier 2025. Évolution, état et utilisation de la forêt suisse. Berne; Birmensdorf: Office fédéral de l'environnement OFEV; Institut fédéral de recherches sur la forêt, la neige et le paysage WSL. 74-77.
• La composition en essences change dans la forêt suisse. Le frêne et le châtaignier sont en recul, l'érable, l'arole et le nombre moyen d'espèces de
mousses et de mollusques augmentent.
• Environ 40% des espèces animales et végétales de Suisse vivent en forêt, avec une part particulièrement élevée chez les lichens, les champignons supérieurs, les chauves-souris et les capricornes.
• Le recul du frêne affectera les biocénoses qui lui sont associées, comme les lichens, les mousses et les champignons. En outre, les changements climatiques, les néophytes envahissantes et les dépôts atmosphériques azotés continueront de transformer la composition en essences des forêts. -
Bollmann K., Stofer S., Abegg M., Thrippleton T. (2025) Species diversity. In A. Strauss & C. Fischer (Eds.), Forest Report 2025. Development, condition and use of Swiss forests. Bern; Birmensdorf: Federal Office for the Environment FOEN; Swiss Federal Institute for Forest, Snow and Landscape Research WSL. 74-77.
• The species composition in Swiss forests is changing. While ash and sweet chestnut have declined, there have been increases in maple and Arolla pine and in the average number of moss and gastropod species.
• Around 40% of Switzerland’s animal and plant species live in forests, with the proportion of forest-dwelling species particularly high among lichens, macrofungi, bats and longhorn beetles.
• The decline of ash trees will adversely affect the communities associated with them, such as lichens, mosses and fungi. In addition, climate change, invasive neophytes and atmospheric nitrogen deposition are set to further alter the species composition in forests. -
Bütler R., Gossner M., Lachat T., Abegg M., Lauper B. (2025) Bois mort. In A. Strauss & C. Fischer (Eds.), Rapport forestier 2025. Évolution, état et utilisation de la forêt suisse. Berne; Birmensdorf: Office fédéral de l'environnement OFEV; Institut fédéral de recherches sur la forêt, la neige et le paysage WSL. 84-85.
• Le volume de bois mort en Suisse a augmenté à 32 mètres cubes par hectare (m³/ha) durant la dernière décennie. L'objectif politique a ainsi été atteint dans la plupart des régions. Mais sur le Plateau, il est par endroits inférieur à 20 m³/ha.
• Ces deux valeurs ne suffisent que pour les espèces peu exigeantes. Les vieux arbres aux microhabitats très diversifiés et les gros bois morts sont encore trop rares. Des mesures s'imposent pour conserver le gros bois mort et de vieux arbres accomplissant tout leur cycle de vie.
• La demande accrue en bois pourrait menacer l'évolution positive du volume de bois mort. -
Bütler R., Gossner M., Lachat T., Abegg M., Lauper B. (2025) Deadwood. In A. Strauss & C. Fischer (Eds.), Forest Report 2025. Development, condition and use of Swiss forests. Bern; Birmensdorf: Federal Office for the Environment FOEN; Swiss Federal Institute for Forest, Snow and Landscape Research WSL. 84-85.
• The deadwood volume across Switzerland has increased to 32 cubic metres per hectare in the past decade, meaning that this forest policy objective has been achieved in most regions. On the Plateau, however, there is less than 20 cubic metres of deadwood per hectare in some regions.
• Both values are sufficient only for species with low deadwood requirements. Old trees with a wide variety of microhabitats and large-diameter deadwood are still too scarce. Measures are needed to promote large-diameter deadwood and old trees that complete their entire life cycle.
• The growing demand for wood could jeopardise the positive trend towards higher deadwood volumes. -
Bütler R., Gossner M., Lachat T., Abegg M., Lauper B. (2025) Legno morto. In A. Strauss & C. Fischer (Eds.), Rapporto forestale 2025. Evoluzione, stato e utilizzazione del bosco svizzero. Berna; Birmensdorf: Ufficio federale dell'ambiente (UFAM); Istituto federale di ricerca per la foresta, la neve e il paesaggio (WSL). 84-85.
• Nell'ultimo decennio il volume di legno morto è salito a 32 metri cubi per ettaro a livello nazionale. Questo obiettivo di politica forestale è stato quindi raggiunto nella maggior parte delle regioni. Sull'Altipiano, invece, in alcune regioni si rilevano meno di 20 metri cubi di legno morto per ettaro.
• Entrambi i valori sono sufficienti solo per le specie con basse esigenze in termini di legno morto. Gli alberi vecchi con una grande varietà di microhabitat e il legno morto di grandi dimensioni sono ancora una rarità. Servono quindi misure per promuoverli lungo l'intero ciclo di vita.
• La crescente domanda di legno potrebbe compromettere la tendenza positiva all'aumento del volume di legno morto. -
Bütler R., Gossner M., Lachat T., Abegg M., Lauper B. (2025) Totholz. In A. Strauss & C. Fischer (Eds.), Waldbericht 2025. Entwicklung, Zustand und Nutzung des Schweizer Waldes. Bern; Birmensdorf: Bundesamt für Umwelt BAFU; Eidg. Forschungsanstalt für Wald Schnee und Landschaft WSL. 84-85.
• Das Totholzvolumen hat sich in der letzten Dekade schweizweit auf 32 Kubikmeter pro Hektare erhöht. Somit ist dieses waldpolitische Ziel in den meisten Regionen erreicht. Im Mittelland gibt es aber in gewissen Regionen weniger als 20 Kubikmeter Totholz pro Hektare.
• Beide Werte reichen nur für Arten mit niedrigen Totholzansprüchen aus. Alte Bäume mit grosser Vielfalt an Mikrohabitaten und dickes Totholz sind noch zu selten. Es besteht ein Bedarf an Massnahmen zur Förderung von dickem Totholz und alten Bäumen, die den vollständigen Lebenszyklus durchlaufen.
• Die steigende Nachfrage nach Holz könnte den positiven Trend zu höheren Totholzvolumen gefährden. -
Cioldi F., Kunnala M. (2025) Growing stock. In A. Strauss & C. Fischer (Eds.), Forest Report 2025. Development, condition and use of Swiss forests. Bern; Birmensdorf: Federal Office for the Environment FOEN; Swiss Federal Institute for Forest, Snow and Landscape Research WSL. 32-33.
• The growing stock has remained constant over the past decade throughout Switzerland. However, trends varied from region to region. The growing stock increased by 12% on the southern side of the Alps and by 7% in the Alps, while on the Plateau and in the Jura it declined by 5% and 3% respectively.
• The total growing stock of living trees in Swiss forests stands at 420 million cubic metres, or 347 cubic metres per hectare. Conifers make up 68% of the growing stock and broadleaved trees 32%.
• Climate change will have a major impact on growing stock development and future tree species composition. In the Jura and on the Plateau, growing stock declines are expected to continue as a result of increased mortality and salvage logging. -
Cioldi F., Kunnala M. (2025) Holzvorrat. In A. Strauss & C. Fischer (Eds.), Waldbericht 2025. Entwicklung, Zustand und Nutzung des Schweizer Waldes. Bern; Birmensdorf: Bundesamt für Umwelt BAFU; Eidg. Forschungsanstalt für Wald Schnee und Landschaft WSL. 32-33.
• Landesweit ist der Holzvorrat in der letzten Dekade konstant geblieben. Regional waren die Entwicklungen jedoch unterschiedlich. Auf der Alpensüdseite ist der Vorrat um 12 % und in den Alpen um 7 % angewachsen. Im Mittelland und im Jura hat er um 5 % bzw. 3 % abgenommen.
• Der gesamte Holzvorrat der lebenden Bäume im Schweizer Wald beläuft sich auf 420 Millionen Kubikmeter. Das entspricht 347 Kubikmetern pro Hektare. Vom Holzvorrat entfallen 68 % auf Nadelbäume, 32 % auf Laubbäume.
• Der Klimawandel wird die Vorratsentwicklung und die künftige Baumartenzusammensetzung stark beeinflussen. Im Jura und im Mittelland werden sich die Vorratsabnahmen als Folge erhöhter Mortalität und Zwangsnutzungen voraussichtlich fortsetzen. -
Cioldi F., Kunnala M. (2025) Provvigione legnosa. In A. Strauss & C. Fischer (Eds.), Rapporto forestale 2025. Evoluzione, stato e utilizzazione del bosco svizzero. Berna; Birmensdorf: Ufficio federale dell'ambiente (UFAM); Istituto federale di ricerca per la foresta, la neve e il paesaggio (WSL). 32-33.
• A livello nazionale, la provvigione legnosa è rimasta costante nell'ultimo decennio, pur evolvendosi in modo differente a livello regionale. Al Sud delle Alpi è cresciuta del 12 per cento e nelle Alpi del 7 per cento, mentre sull'Altipiano e nel Giura è diminuita rispettivamente del 5 e del 3 per cento.
• L'intera provvigione degli alberi vivi ammonta a 420 milioni di metri cubi, ovvero 347 metri cubi per ettaro. Il 68 per cento è rappresentato da conifere e il 32 per cento da latifoglie.
• Il cambiamento climatico avrà un forte impatto sulla futura composizione delle specie arboree. Nel Giura e sull'Altipiano è probabile che la provvigione continuerà a diminuire a causa dell’aumento della mortalità e delle utilizzazioni forzate. -
Cioldi F., Kunnala M. (2025) Volume de bois. In A. Strauss & C. Fischer (Eds.), Rapport forestier 2025. Évolution, état et utilisation de la forêt suisse. Berne; Birmensdorf: Office fédéral de l'environnement OFEV; Institut fédéral de recherches sur la forêt, la neige et le paysage WSL. 32-33.
• Au niveau suisse, le volume de bois est resté constant durant la dernière décennie, mais il a évolué de façon variable selon les régions. Ainsi, il a augmenté de 12% dans le sud des Alpes et de 7% dans les Alpes, alors qu'il a diminué de 5% sur le Plateau et de 3% dans le Jura.
• Le volume total des arbres vifs dans la forêt suisse s'élève à 420 millions de m3, soit 347 m3 par ha. Il est constitué à 68% de résineux et à 32% de feuillus.
• Les changements climatiques auront une grande influence sur l'évolution du volume de bois et la composition future en essences. Dans le Jura et sur le Plateau, les reculs du volume consécutifs à la mortalité accrue et aux exploitations forcéesdevraient se poursuivre. -
Conedera M., Streit K., Abegg M., Jenni R., Lauper B. (2025) Essences non indigènes. In A. Strauss & C. Fischer (Eds.), Rapport forestier 2025. Évolution, état et utilisation de la forêt suisse. Berne; Birmensdorf: Office fédéral de l'environnement OFEV; Institut fédéral de recherches sur la forêt, la neige et le paysage WSL. 82-83.
• La culture ciblée d'essences non indigènes reste marginale dans l'économie forestière suisse. Durant la dernière décennie, la surface dominée par ces essences est passée de 0,2 à 0,7%.
• Dans certaines conditions environnementales, des espèces ligneuses non indigènes peuvent se propager de manière invasive, surtout à basse altitude. La culture d'essences non indigènes non envahissantes en tant que stratégie d'adaptation aux changements climatiques gagne en importance.
• Les risques et les chances que comporte l'utilisation de ces essences doivent être soigneusement évalués. La gestion des espèces envahissantes est à prendre en compte dans la planification forestière. -
Conedera M., Streit K., Abegg M., Jenni R., Lauper B. (2025) Nicht einheimische Baumarten. In A. Strauss & C. Fischer (Eds.), Waldbericht 2025. Entwicklung, Zustand und Nutzung des Schweizer Waldes. Bern; Birmensdorf: Bundesamt für Umwelt BAFU; Eidg. Forschungsanstalt für Wald Schnee und Landschaft WSL. 82-83.
• Der gezielte Anbau nicht einheimischer Baumarten spielt in der Schweizer Waldwirtschaft nach wie vor eine kleine Rolle. In der letzten Dekade hat sich die Fläche, auf der solche Arten dominieren, um 0,2 % auf 0,7 % erhöht.
• Unter besonderen Umweltbedingungen können sich nicht einheimische Gehölzarten invasiv ausbreiten, vor allem in tieferen Lagen. Als Strategie zur Anpassung an den Klimawandel gewinnt der Anbau nicht invasiver gebietsfremder Baumarten an Bedeutung.
• Beim Einsatz nicht einheimischer Baumarten müssen die Risiken und Chancen sorgfältig abgewogen werden. Der Umgang mit invasiven Arten muss in die waldbauliche Planung einbezogen werden. -
Conedera M., Streit K., Abegg M., Jenni R., Laupber B. (2025) Non-native tree species. In A. Strauss & C. Fischer (Eds.), Forest Report 2025. Development, condition and use of Swiss forests. Bern; Birmensdorf: Federal Office for the Environment FOEN; Swiss Federal Institute for Forest, Snow and Landscape Research WSL. 82-83.
• Targeted cultivation of non-native tree species still plays a minor role in Swiss forestry. The area dominated by such species has increased by 0.2% to 0.7% over the past decade.
• Under particular environmental conditions, non-native woody species may spread invasively, especially at lower altitudes. The cultivation of non-invasive, non-native tree species is also becoming increasingly important as a climate change adaptation strategy.
• The risks and opportunities of using non-native tree species must be carefully weighed up, and invasive species management must be included in silvicultural planning. -
Conedera M., Streit K., Abegg M., Jenni R., Lauper B. (2025) Specie arboree non autoctone. In A. Strauss & C. Fischer (Eds.), Rapporto forestale 2025. Evoluzione, stato e utilizzazione del bosco svizzero. Berna; Birmensdorf: Ufficio federale dell'ambiente (UFAM); Istituto federale di ricerca per la foresta, la neve e il paesaggio (WSL). 82-83.
• La coltivazione mirata di specie arboree non autoctone continua a svolgere un ruolo minore nella selvicoltura
svizzera. Nell'ultimo decennio la superficie su cui dominano queste specie è cresciuta dallo 0,2 allo 0,7 per cento.
• In particolari condizioni ambientali, le specie legnose non autoctone possono diffondersi in modo invasivo, soprattutto alle basse altitudini. La coltivazione di specie arboree esotiche non invasive sta diventando sempre più importante come strategia di adattamento al cambiamento climatico.
• Occorre ponderarne attentamente i rischi e i benefici così come il loro impiego deve essere integrato nella
pianificazione selvicolturale. -
Fassnacht F.E., Mager C., Waser L.T., Kanjir U., Schäfer J., Buhvald A.P., … Skudnik M. (2025) Forest practitioners' requirements for remote sensing-based canopy height, wood-volume, tree species, and disturbance products. Forestry. 98(2), 233-252. https://doi.org/10.1093/forestry/cpae021
Despite decades of development, the uptake of remote sensing-based information products in the forestry sector is still lagging behind in central and southern Europe. This may partly relate to a mismatch of the developed remote sensing products and the requirements of potential users. Here, we present the results of a questionnaire survey in which we questioned 355 forest practitioners from eight central and southern European countries. We aimed to learn about forest practitioners' technical requirements for four remote sensing-based information products, including information on tree species, canopy height, wood volume/biomass, and forest disturbances. We asked for practitioners’ preferences with respect to thematic and spatial detail as well as the maximal acceptable error and the temporal frequency with which the information layers would be needed. We then examined whether the education, age, and professional background affect the requirements. Preferences with respect to spatial and thematic detail were comparably diverse while more homogenous patterns could be observed for demands with respect to errors and temporal frequency. Our results indicate that for some information products such as canopy height maps, existing remote sensing technology, and workflows can match all demands of practitioners. Remotely sensed information on forest disturbances partly fulfils the demands of the practitioners while for products related to tree species and wood volume/biomass the level of thematic detail and the accuracy of the products demanded by practitioners in central and southern Europe is not yet fully matched. We found no statistically significant differences between the demographic groups examined. The findings of this study improve our understanding of matches and mismatches of the technical requirements of practitioners for remote sensing-based information products.
DOI: 10.1093/forestry/cpae021
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Fischer C., Strauss A. (2025) Bases de données. In A. Strauss & C. Fischer (Eds.), Rapport forestier 2025. Évolution, état et utilisation de la forêt suisse. Berne; Birmensdorf: Office fédéral de l'environnement OFEV; Institut fédéral de recherches sur la forêt, la neige et le paysage WSL. 23-25.
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Fischer C., Strauss A. (2025) Data basis. In A. Strauss & C. Fischer (Eds.), Forest Report 2025. Development, condition and use of Swiss forests. Bern; Birmensdorf: Federal Office for the Environment FOEN; Swiss Federal Institute for Forest, Snow and Landscape Research WSL. 23-25.
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Fischer C., Strauss A. (2025) Datengrundlage. In A. Strauss & C. Fischer (Eds.), Waldbericht 2025. Entwicklung, Zustand und Nutzung des Schweizer Waldes. Bern; Birmensdorf: Bundesamt für Umwelt BAFU; Eidg. Forschungsanstalt für Wald Schnee und Landschaft WSL. 23-25.
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Fischer C., Husistein M. (2025) Resources. In A. Strauss & C. Fischer (Eds.), Forest Report 2025. Development, condition and use of Swiss forests. Bern; Birmensdorf: Federal Office for the Environment FOEN; Swiss Federal Institute for Forest, Snow and Landscape Research WSL. 29-39.
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Fischer C., Husistein M. (2025) Ressourcen. In A. Strauss & C. Fischer (Eds.), Waldbericht 2025. Entwicklung, Zustand und Nutzung des Schweizer Waldes. Bern; Birmensdorf: Bundesamt für Umwelt BAFU; Eidg. Forschungsanstalt für Wald Schnee und Landschaft WSL. 29-39.
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Fischer C., Husistein M. (2025) Ressources. In A. Strauss & C. Fischer (Eds.), Rapport forestier 2025. Évolution, état et utilisation de la forêt suisse. Berne; Birmensdorf: Office fédéral de l'environnement OFEV; Institut fédéral de recherches sur la forêt, la neige et le paysage WSL. 29-39.
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Fischer C., Husistein M. (2025) Risorse. In A. Strauss & C. Fischer (Eds.), Rapporto forestale 2025. Evoluzione, stato e utilizzazione del bosco svizzero. Berna; Birmensdorf: Ufficio federale dell'ambiente (UFAM); Istituto federale di ricerca per la foresta, la neve e il paesaggio (WSL). 29-39.
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Kunnala M., Temperli C. (2025) Exploitation du bois et accroissement. In A. Strauss & C. Fischer (Eds.), Rapport forestier 2025. Évolution, état et utilisation de la forêt suisse. Berne; Birmensdorf: Office fédéral de l'environnement OFEV; Institut fédéral de recherches sur la forêt, la neige et le paysage WSL. 60-61.
• L'accroissement brut et l'accroissement net sont en recul dans certaines régions.
• La mortalité a fortement augmenté et atteint 25% de l'accroissement brut. Les exploitations forcées imprévues après des perturbations étaient aussi en forte hausse.
• Il est probable que des évolutions comme la hausse de la mortalité et la diminution de l'accroissement se poursuivent, avec des différences régionales. La gestion forestière sera donc de plus en plus influencée par la maîtrise de perturbations. -
Kunnala M., Temperli C. (2025) Haravesting and increment. In A. Strauss & C. Fischer (Eds.), Forest Report 2025. Development, condition and use of Swiss forests. Bern; Birmensdorf: Federal Office for the Environment FOEN; Swiss Federal Institute for Forest, Snow and Landscape Research WSL. 60-61.
• Both gross and net increment in Swiss forests are declining in some regions.
• Mortality has risen sharply and accounts for 25% of the gross increment. There has also been a big increase in salvage logging following disturbances.
• Developments such as higher mortality and reduced increment are expected to continue, with regional differences. Disturbance management will therefore be an increasingly important factor in forest management. -
Kunnala M., Temperli C. (2025) Holznutzung und Zuwachs. In A. Strauss & C. Fischer (Eds.), Waldbericht 2025. Entwicklung, Zustand und Nutzung des Schweizer Waldes. Bern; Birmensdorf: Bundesamt für Umwelt BAFU; Eidg. Forschungsanstalt für Wald Schnee und Landschaft WSL. 60-61.
• Sowohl der Brutto- als auch der Nettozuwachs sind regional rückläufig.
• Die Mortalität ist stark gestiegen und beträgt 25 % des Bruttozuwachses. Ebenfalls haben ungeplante Zwangsnutzungen nach Störungen stark zugenommen.
• Entwicklungen wie erhöhte Mortalität und verringerter Zuwachs werden, mit regionalen Unterschieden, voraussichtlich anhalten. Die Waldbewirtschaftung wird somit vermehrt durch die Störungsbewältigung mitbeeinflusst werden. -
Kunnala M., Temperli C. (2025) Utilizzazione legnosa e incremento. In A. Strauss & C. Fischer (Eds.), Rapporto forestale 2025. Evoluzione, stato e utilizzazione del bosco svizzero. Berna; Birmensdorf: Ufficio federale dell'ambiente (UFAM); Istituto federale di ricerca per la foresta, la neve e il paesaggio (WSL). 60-61.
• Sia l'incremento netto che quello lordo sono in calo a livello regionale.
• La mortalità è fortemente aumentata e corrisponde al 25 per cento dell'incremento lordo. A seguito
di perturbazioni, si è registrato anche un sensibile aumento delle utilizzazioni forzate non programmate.
• È probabile che queste tendenze continuino, seppur con differenze a livello regionale. La gestione forestale
sarà quindi sempre più improntata al controllo di questi fenomeni. -
König L.A., Mohren F., Schelhaas M.J., Astigarraga J., Cienciala E., Flury R., … Nabuurs G.J. (2025) Combining national forest inventories reveals distinct role of climate on tree recruitment in European forests. Ecol. Model. 505, 111112 (14 pp.). https://doi.org/10.1016/j.ecolmodel.2025.111112
Tree recruitment forms an essential process in forest growth models as it determines the amount and composition of the next generation of trees and, hence, the provision of forest ecosystem services over long time spans. With global change and the hereby associated changes in environmental conditions and forest management adaptations, the common static tree recruitment modelling approaches have become largely obsolete and necessitated the development of more dynamic models. Limited by the availability of data for the parameterisation of tree recruitment processes, such models have only been developed for single species or national frameworks and largely failed to detect climatic influences. In this study, we developed a dynamic tree recruitment model for Europe, utilising National Forest Inventory data from 8 countries with more than 95,000 repeated plot observations and nearly 138,000 individual tree recruitment events. We investigated the effect of forest management, forest structure, soil characteristics, nutrient deposition and five groups of weather and climate variables on the quantity and the species composition of recruiting trees. The climatic groups spanned annual averages, intra annual averages, annual variability, intra annual extremes and a combination of the aforementioned groups. The model with the combination of climate and weather variables outperformed all other groups. We found distinct climatic effects on tree recruitment quantities linked to water limitations and temperature extremes. The results as such showed that tree recruitment quantities benefit from stable climatic conditions, high precipitation and suffer from high maximum temperatures. Increasing temperatures also facilitate the share of recruiting broadleaves. The recruitment species was largely determined by the lead species in a plot, indicating the importance of seed limitation. Furthermore, the results confirm the important role of forest structure in tree recruitment and enable forest managers to steer the next generation of trees. Especially multi-species stands show a clear advantage over single species stands regarding tree recruitment quantities and diverse species compositions. Our research enables dynamic and state-of-the-art recruitment simulations across forests in Europe. It presents a reproducible method that can be applied to forest simulation modelling frameworks.
DOI: 10.1016/j.ecolmodel.2025.111112
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Kükenbrink D., Marty M., Rehush N., Abegg M., Ginzler C. (2025) Evaluating the potential of handheld mobile laser scanning for an operational inclusion in a national forest inventory – A Swiss case study. Remote Sens. Environ. 321, 114685 (15 pp.). https://doi.org/10.1016/j.rse.2025.114685
Close-range remote sensing technologies show great potential to support national forest inventories (NFIs). Mobile laser scanning (MLS) has performed especially well in recent studies, as it is capable of fast data acquisition while still delivering accurate information on NFI-relevant variables (e.g. tree position, diameter at breast height [DBH]). However, the performance of MLS acquisition under challenging conditions (e.g. steep terrain, dense understorey vegetation) has rarely been addressed. Here, on 29 NFI plots distributed over the entire country of Switzerland and representing various terrain and forest conditions, we evaluated the use and performance of handheld MLS acquisition, using a GeoSLAM ZebHorizon laser scanner, to deliver analysis-ready (with minimal occlusion) point clouds and to estimate primary tree variables such as tree position and DBH. Data acquisition was successful for all tested Swiss NFI plots. The average time needed for point cloud acquisition of a 50 × 50 m sample plot was 13.13 min. Over all tested NFI plots, we achieved a tree detection rate of 82.6%, with a relative root mean square error (RMSE) of 7.25%, a mean absolute error of 2.0 cm and a systematic prediction error (SPE) of 1.0 cm for DBH estimation. The terrain gradient had an especially strong influence on the accuracy of DBH estimation. Occlusion, as a metric for point cloud capacity to hold forest structural information for the entire canopy volume, was minimal when the suggested acquisition pattern was followed, at 9% on average for the entire canopy volume. However, the level of occlusion increased in the upper part of the canopy (> 10 m above ground), to 15% on average.
Overall, handheld MLS effectively produced analysis-ready point clouds within the 15-minute acquisition time limitation for a 50 x 50 m area, even under challenging conditions, showing promise for future use in the Swiss NFI. However, the current accuracy of MLS-estimated forest variables like DBH and tree detection is insufficient to replace conventional measurements within an established NFI. Despite this, estimating NFI-relevant variables, even with lower accuracy, and expanding the area of measured tree variables could improve information on forest functions and services (e.g., protection and biodiversity), currently not possible to derive from NFI data due to the limited plot size. In the future, MLS-acquired point clouds could (1) shift from expert-assessed to more quantitative and reproducible variable estimation, and (2) enhance NFI with variables difficult to measure conventionally. This could open new pathways for assessing and monitoring forest structural diversity nationally and provide valuable calibration and validation data for large-scale forest assessments from airborne or space-borne acquisitions.DOI: 10.1016/j.rse.2025.114685
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Margolis E., Wion A., Abatzoglou J., Daniels L., Falk D., Guiterman C., … Yocom L. (2025) Spatiotemporal synchrony of climate and fire occurrence across North American forests (1750–1880). Glob. Ecol. Biogeogr. 34(1), e13937 (14 pp.). https://doi.org/10.1111/geb.13937
Aim: Increasing aridity has driven widespread synchronous fire occurrence in recent decades across North America. The lack of historical (pre-1880) fire records limits our ability to understand long-term continental fire-climate dynamics. The goal of this study is to use tree-ring reconstructions to determine the relationships between spatiotemporal patterns in historical climate and widespread fire occurrence in North American forests, and whether they are stable through time. This information will address a major knowledge gap required to inform projections of future fire.
Location: North American Forests.
Time Period: 1750–1880 CE.
Major Taxa Studied: Trees.
Methods: We applied regionalisation methods to tree-ring reconstructions of historical summer soil moisture and annual fire occurrence to independently identify broad- and fine-scale climate and fire regions based on common inter-annual variability. We then tested whether the regions were stable through time and for spatial correspondence between the climate and fire regions. Last, we used correlation analysis to quantify the strength of the fire-climate associations through time.
Results: We found that broad-scale historical patterns in climate and fire have strong spatial coherence. Although climate and fire regions vary over time, large core areas of the regions were stable. The association between climate and fire varied through time and was strongest in western North America, likely due to a combination of factors, such as the magnitude of drought frequency and severity, as well as varying use of fire by human communities.
Main Conclusions: The historical perspective gained through tree-ring reconstructions of climate and fire patterns and their association suggests that climate-driven synchrony of fire across large areas of the continent in recent decades is not unprecedented, will likely continue into the future, and may exhibit similar spatial patterns.DOI: 10.1111/geb.13937
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Moser B., Abegg M., Kupferschmid A.D., Nikolova P., Scherrer D., Thrippleton T., Jenni R. (2025) Regeneration. In A. Strauss & C. Fischer (Eds.), Forest Report 2025. Development, condition and use of Swiss forests. Bern; Birmensdorf: Federal Office for the Environment FOEN; Swiss Federal Institute for Forest, Snow and Landscape Research WSL. 78-79.
• The density of young trees has decreased in the past decade as the regeneration areas created by storms Vivian and Lothar have grown over again. Ungulate browsing is also influencing the species composition in many regions and reducing the regeneration density. Both young-growth and adult populations of ash north of the Alps and of sweet chestnut in Ticino have declined.
• Natural regeneration is the dominant form of regeneration in Swiss forests, accounting for 90.9% of the total regeneration area. This reflects the economic and ecological advantages of natural regeneration in close-to-nature forest management.
• Species-rich tree regeneration is necessary to ensure forest’s resilience to disturbances and its ability to adapt to climate change. -
Moser B., Abegg M., Kupferschmid A.D., Nikolova P., Scherrer D., Thrippleton T., Jenni R. (2025) Rinnovazione. In A. Strauss & C. Fischer (Eds.), Rapporto forestale 2025. Evoluzione, stato e utilizzazione del bosco svizzero. Berna; Birmensdorf: Ufficio federale dell'ambiente (UFAM); Istituto federale di ricerca per la foresta, la neve e il paesaggio (WSL). 78-79.
• Nell'ultimo decennio la densità dei giovani alberi è diminuita perché le aree di rinnovazione create dalle tempeste Vivian e Lothar sono tornate a essere invase dalla vegetazione. Anche il brucamento della fauna selvatica influenza la mescolanza delle specie in molte regioni e riduce la densità di rinnovazione. Nei popolamenti di frassino al Nord delle Alpi e di castagno in Ticino sono diminuiti sia gli alberi giovani che quelli adulti.
• Nel bosco svizzero domina la rinnovazione naturale, che in termini di superficie rappresenta il 90,9 per cento della rinnovazione complessiva e riflette i vantaggi economici ed ecologici della selvicoltura naturalistica.
• Per garantire la resilienza del bosco alle perturbazioni e la sua capacità di adattarsi al cambiamento climatico, è necessaria una rinnovazione degli alberi ricca di specie. -
Moser B., Abegg M., Kupferschmid A.D., Nikolova P., Scherrer D., Thrippleton T., Jenni R. (2025) Régénération. In A. Strauss & C. Fischer (Eds.), Rapport forestier 2025. Évolution, état et utilisation de la forêt suisse. Berne; Birmensdorf: Office fédéral de l'environnement OFEV; Institut fédéral de recherches sur la forêt, la neige et le paysage WSL. 78-79.
• La densité des jeunes arbres a diminué durant la dernière décennie, les surfaces de régénération créées par les tempêtes Vivian et Lothar ayant été recolonisées entre-temps. Dans de nombreuses régions, l'abroutissement influence lui aussi la composition en espèces et réduit la densité du rajeunissement. Les peuplements de frênes dans le nord des Alpes et de châtaigniers au Tessin ont diminué tant pour le recrû que pour les arbres adultes.
• Dans les forêts suisses, la régénération naturelle représente 90,9% de la surface totale de régénération. Cette prédominance reflète les avantages économiques et écologiques de sa mise en oeuvre dans la sylviculture proche de la nature.
• Une régénération riche en espèces est nécessaire pour garantir la résilience de la forêt lors de perturbations et sa capacité d’adaptation aux changements climatiques. -
Moser B., Abegg M., Kupferschmid A.D., Nikolova P., Scherrer D., Thrippleton T., Jenni R. (2025) Verjüngung. In A. Strauss & C. Fischer (Eds.), Waldbericht 2025. Entwicklung, Zustand und Nutzung des Schweizer Waldes. Bern; Birmensdorf: Bundesamt für Umwelt BAFU; Eidg. Forschungsanstalt für Wald Schnee und Landschaft WSL. 78-79.
• Die Dichte der Jungbäume hat in der letzten Dekade abgenommen, indem die von den Stürmen Vivian und Lothar geschaffenen Verjüngungsflächen wieder zugewachsen sind. Auch der Wildverbiss beeinflusst in vielen Regionen die Artenzusammensetzung und reduziert die Verjüngungsdichte. Die Bestände der Esche nördlich der Alpen und der Kastanie im Tessin haben sowohl beim Jungwuchs als auch bei den adulten Bäumen abgenommen.
• Im Schweizer Wald dominiert die Naturverjüngung mit einem Flächenanteil von 90,9 % an der Gesamtverjüngung. Dies ist Ausdruck der ökonomischen und ökologischen Vorteile der Naturverjüngung im naturnahen Waldbau.
• Um die Resilienz des Waldes bei Störungen sowie die Anpassungsfähigkeit an den Klimawandel zu gewährleisten, ist eine artenreiche Baumverjüngung erforderlich. -
Parks S.A., Guiterman C.H., Margolis E.Q., Lonergan M., Whitman E., Abatzoglou J.T., … Yocom L.L. (2025) A fire deficit persists across diverse North American forests despite recent increases in area burned. Nat. Commun. 16, 1493 (13 pp.). https://doi.org/10.1038/s41467-025-56333-8
Rapid increases in wildfire area burned across North American forests pose novel challenges for managers and society. Increasing area burned raises questions about whether, and to what degree, contemporary fire regimes (1984–2022) are still departed from historical fire regimes (pre-1880). We use the North American tree-ring fire-scar network (NAFSN), a multi-century record comprising >1800 fire-scar sites spanning diverse forest types, and contemporary fire perimeters to ask whether there is a contemporary fire surplus or fire deficit, and whether recent fire years are unprecedented relative to historical fire regimes. Our results indicate, despite increasing area burned in recent decades, that a widespread fire deficit persists across a range of forest types and recent years with exceptionally high area burned are not unprecedented when considering the multi-century perspective offered by fire-scarred trees. For example, 'record' contemporary fire years such as 2020 burned 6% of NAFSN sites—the historical average—well below the historical maximum of 29% sites that burned in 1748. Although contemporary fire extent is not unprecedented across many North American forests, there is abundant evidence that unprecedented contemporary fire severity is driving forest loss in many ecosystems and adversely impacting human lives, infrastructure, and water supplies.
DOI: 10.1038/s41467-025-56333-8
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Puliti S., Lines E.R., Müllerová J., Frey J., Schindler Z., Straker A., … Astrup R. (2025) Benchmarking tree species classification from proximally sensed laser scanning data: introducing the FOR ‐ species20K dataset. Methods Ecol. Evol. 16(4), 801-818. https://doi.org/10.1111/2041-210X.14503
1. Proximally sensed laser scanning presents new opportunities for automated forest ecosystem data capture. However, a gap remains in deriving ecologically pertinent information, such as tree species, without additional ground data. Artificial intelligence approaches, particularly deep learning (DL), have shown promise towards automation. Progress has been limited by the lack of large, diverse, and, most importantly, openly available labelled single-tree point cloud datasets. This has hindered both (1) the robustness of the DL models across varying data types (platforms and sensors) and (2) the ability to effectively track progress, thereby slowing the convergence towards best practice for species classification.
2. To address the above limitations, we compiled the FOR-species20K benchmark dataset, consisting of individual tree point clouds captured using proximally sensed laser scanning data from terrestrial (TLS), mobile (MLS) and drone laser scanning (ULS). Compiled collaboratively, the dataset includes data collected in forests mainly across Europe, covering Mediterranean, temperate and boreal biogeographic regions. It includes scattered tree data from other continents, totaling over 20,000 trees of 33 species and covering a wide range of tree sizes and forms. Alongside the release of FOR-species20K, we benchmarked seven leading DL models for individual tree species classification, including both point cloud (PointNet++, MinkNet, MLP-Mixer, DGCNNs) and multi-view 2D-based methods (SimpleView, DetailView, YOLOv5).
3. 2D Image-based models had, on average, higher overall accuracy (0.77) than 3D point cloud-based models (0.72). Notably, the performance was consistently >0.8 across scanning platforms and sensors, offering versatility in deployment. The top-scoring model, DetailView, demonstrated robustness to training data imbalances and effectively generalized across tree sizes.
4. The FOR-species20K dataset represents an important asset for developing and benchmarking DL models for individual tree species classification using proximally sensed laser scanning data. As such, it serves as a crucial foundation for future efforts to classify accurately and map tree species at various scales using laser scanning technology, as it provides the complete code base, dataset, and an initial baseline representative of the current state-of-the-art of point cloud tree species classification methods.DOI: 10.1111/2041-210X.14503
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Queloz V., Conedera M., Boris Pezzatti G., Sautter M., Stroheker S., Abegg M., … Blaser S. (2025) Danni al bosco. In A. Strauss & C. Fischer (Eds.), Rapporto forestale 2025. Evoluzione, stato e utilizzazione del bosco svizzero. Berna; Birmensdorf: Ufficio federale dell'ambiente (UFAM); Istituto federale di ricerca per la foresta, la neve e il paesaggio (WSL). 50-53.
• L'aumento delle temperature e dei periodi di siccità comportano un maggior rischio di incendi boschivi. L'effetto combinato di questi fattori abiotici e dei parassiti autoctoni e alloctoni comporta eventi dannosi nuovi sia per tipologia che per dimensioni.
• Spesso gli alberi dei boschi sono indeboliti e in aree isolate o localizzate deperiscono a causa di cambiamenti
del clima, incendi, grandinate, complesse fitopatologie o diffusione di specie invasive.
• Affinché il bosco possa continuare a fornire le sue prestazioni sono essenziali specie arboree più resistenti
al cambiamento climatico e agli organismi nocivi anche per la loro provenienza. -
Queloz V., Conedera M., Boris Pezzatti G., Sautter M., Stroheker S., Abegg M., … Blaser S. (2025) Dégâts aux forêts. In A. Strauss & C. Fischer (Eds.), Rapport forestier 2025. Évolution, état et utilisation de la forêt suisse. Berne; Birmensdorf: Office fédéral de l'environnement OFEV; Institut fédéral de recherches sur la forêt, la neige et le paysage WSL. 50-53.
• La hausse des températures et la multiplication des périodes de sécheresse accroissent le danger d'incendie de forêt. Les effets combinés de ce type de
facteurs abiotiques et d'organismes nuisibles indigènes et exotiques causent des dégâts d'une nature et d'une ampleur inédites.
• En bien des endroits, les arbres sont affaiblis et ont subi des pertes isolées ou étendues résultant des changements climatiques, d'incendies de forêt, de la grêle, de maladies complexes et de la pression d'espèces envahissantes.
• Les essences et provenances plus résistantes aux changements climatiques et aux organismes nuisibles sont indispensables pour que la forêt puisse continuer de fournir ses prestations. -
Queloz V., Conedera M., Pezzatti G.B., Sautter M., Stroheker S., Abegg M., … Blaser S. (2025) Forest damage. In A. Strauss & C. Fischer (Eds.), Forest Report 2025. Development, condition and use of Swiss forests. Bern; Birmensdorf: Federal Office for the Environment FOEN; Swiss Federal Institute for Forest, Snow and Landscape Research WSL. 50-53.
• Higher temperatures and more frequent droughts are increasing the risk of forest fires. The combined effects of such abiotic factors and of native and non-native harmful organisms are generating new types and dimensions of damaging events.
• Forest trees are weakened in many places, and single trees – or in some cases large areas of forest – have died as a result of climate change, forest fires, hail, complex tree diseases and the pressure of invasive species.
• Tree species and provenances that are more resistant
to climate change and harmful organisms are essential to ensure that forests can continue to provide their services. -
Queloz V., Conedera M., Boris Pezzatti G., Sautter M., Stroheker S., Abegg M., … Blaser S. (2025) Waldschäden. In A. Strauss & C. Fischer (Eds.), Waldbericht 2025. Entwicklung, Zustand und Nutzung des Schweizer Waldes. Bern; Birmensdorf: Bundesamt für Umwelt BAFU; Eidg. Forschungsanstalt für Wald Schnee und Landschaft WSL. 50-53.
• Erhöhte Temperaturen sowie die Häufung von Dürreperioden haben eine Zunahme der Waldbrandgefahr zur Folge. Kombinierte Effekte von solchen abiotischen Faktoren und einheimischen und gebietsfremden Schadorganismen führen zu in Art und Dimension neuartigen Schadereignissen.
• Die Waldbäume sind vielerorts geschwächt und infolge von Klimawandel, Waldbrand, Hagel, komplexen Baumkrankheiten und dem Druck invasiver Arten vereinzelt oder lokal flächig abgestorben.
• Baumarten und Herkünfte, die gegen Klimawandel und Schadorganismen resistenter sind, sind unerlässlich, damit der Wald weiterhin seine Leistungen erbringen kann. -
Reinosch E., Backa J., Adler P., Deutscher J., Eisnecker P., Hoffmann K., … Oehmichen K. (2025) Detailed validation of large-scale Sentinel-2-based forest disturbance maps across Germany. Forestry. 98(3), 437-453. https://doi.org/10.1093/forestry/cpae038
Monitoring forest areas with satellite data has become a vital tool to derive information on disturbances in European forests at large scales. An extensive validation of generated maps is essential to evaluate their potential and limitations in detecting various disturbance patterns. Here, we present the validation results of forest disturbance maps generated for four study areas in Germany using Sentinel-2 data from 2018 to 2022. We apply a time series filtering method to map annual forest disturbances larger than 0.1 ha based on spectral clustering and annual change magnitude. The presented method is part of a research study to design a precursor for a national German forest disturbance monitoring system. In this context, annual forest change areas are used to estimate affected timber volume and related economic losses. To better understand the thematic accuracies and the reliability of the area estimates, we performed an independent and extensive validation of the annual product using 20 validation sets embedded in our four study areas and comprising a total of 11 019 sample points. The collected reference datasets are based on an expert interpretation of high-resolution aerial and satellite imagery, including information on the dominant tree species, disturbance cause, and disturbance severity level. Our forest disturbance map achieves an overall accuracy of 99.1 ± 0.1% in separating disturbed from undisturbed forest. This is mainly indicative of the accuracy for undisturbed forest, as that class covers 97.2% of the total forest area. For the disturbed forest class, the user’s accuracy is 84.4 ± 2.0% and producer’s accuracy is 85.1 ± 3.4% for 2018 to 2022. The similar user’s and producer’s accuracies indicate that the total disturbance area is estimated accurately. However, for 2022, we observe an overestimation of the total disturbance extent, which we attribute to the high drought stress in that year leading to false detections, especially around forest edges. The accuracy varies widely among validation sets and seems related to the disturbance cause, the disturbance severity, and the disturbance patch size. User’s accuracies range from 31.0 ± 8.4% to 98.8 ± 1.3%, while producer’s accuracies range from 60.5 ± 37.3% to 100.0 ± 0.0% across the validation sets. These variations highlight that the accuracy of a single local validation set is not representative of a region with a large diversity of disturbance patterns, such as Germany. This emphasizes the need to assess the accuracies of large-scale disturbance products in as many different study areas as possible, to cover different patch sizes, disturbance severities, and disturbance causes.
DOI: 10.1093/forestry/cpae038
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Rogiers N., Hagedorn F., Thürig E. (2025) Carbon stock. In A. Strauss & C. Fischer (Eds.), Forest Report 2025. Development, condition and use of Swiss forests. Bern; Birmensdorf: Federal Office for the Environment FOEN; Swiss Federal Institute for Forest, Snow and Landscape Research WSL. 37-39.
• The absolute carbon stock of forest biomass has remained almost constant over the past decade.
• At 269 tonnes of carbon per hectare, Swiss forests have the highest relative carbon stock in Europe. The carbon stock is around 119 tonnes per hectare in living trees and around 150 tonnes per hectare in deadwood, the organic layer and soil.
• Forests and wood use will continue to play a role in tackling climate change, but this will require resilient and climate-adapted forests. -
Rogiers N., Hagedorn F., Thürig E. (2025) Kohlenstoffvorrat. In A. Strauss & C. Fischer (Eds.), Waldbericht 2025. Entwicklung, Zustand und Nutzung des Schweizer Waldes. Bern; Birmensdorf: Bundesamt für Umwelt BAFU; Eidg. Forschungsanstalt für Wald Schnee und Landschaft WSL. 37-39.
• Der absolute Kohlenstoffvorrat der Waldbiomasse ist in der letzten Dekade nahezu konstant geblieben.
• Mit 269 Tonnen Kohlenstoff pro Hektare hat der Schweizer Wald den höchsten relativen Kohlenstoffvorrat in Europa. In den lebenden Bäumen beläuft er sich auf rund 119 Tonnen pro Hektare. In Totholz, organischer Auflage und Boden sind es rund 150 Tonnen pro Hektare.
• Auch in Zukunft sollen der Wald und die Verwendung von Holz zur Bewältigung des Klimawandels beitragen. Um dies zu gewährleisten, sind resiliente und klimaangepasste Wälder nötig. -
Rogiers N., Hagedorn F., Thürig E. (2025) Riserva di carbonio. In A. Strauss & C. Fischer (Eds.), Rapporto forestale 2025. Evoluzione, stato e utilizzazione del bosco svizzero. Berna; Birmensdorf: Ufficio federale dell'ambiente (UFAM); Istituto federale di ricerca per la foresta, la neve e il paesaggio (WSL). 37-39.
• In termini assoluti, le riserve di carbonio legate alla biomassa del bosco sono rimaste costanti nell'ultimo
decennio.
• Con 269 tonnellate di carbonio per ettaro, il bosco svizzero ha il valore relativo di riserva di carbonio più alto di tutta Europa. Gli alberi vivi ne contengono circa 119 tonnellate per ettaro; nel legno morto, nell'orizzonte organico e nel suolo questo valore sale a circa 150 tonnellate.
• Anche in futuro il bosco e l'utilizzazione di legname devono contribuire a ridurre le conseguenze del cambiamento climatico. Per questo sono necessari boschi resilienti e adattati al clima. -
Rogiers N., Hagedorn F., Thürig E. (2025) Réserves de carbone. In A. Strauss & C. Fischer (Eds.), Rapport forestier 2025. Évolution, état et utilisation de la forêt suisse. Berne, Birmensdorf: Office fédéral de l'environnement OFEV; Institut fédéral de recherches sur la forêt, la neige et le paysage WSL. 37-39.
• Les réserves de carbone absolues de la biomasse forestière sont restées quasi constantes durant la dernière décennie.
• Avec 269 tonnes de carbone par hectare (t C/ha), la forêt suisse contient les stocks relatifs les plus élevés d'Europe. Environ 119 t C/ha sont stockées dans les arbres vifs, et 150 t C/ha dans le bois mort, l'horizon organique et le sol.
• La forêt et l'utilisation du bois devront encore contribuer à l'avenir à la gestion des changements climatiques. Seules des forêts résilientes et adaptées au climat peuvent le garantir. -
Rougemont V., Portier J., Stadelmann G., Aubry M. (2025) Approches suisse et française pour l'adaptation des forêts aux changements climatiques. Schweiz. Z. Forstwes. 176(1), 44-47. https://doi.org/10.3188/szf.2025.0044
Les forêts suisses et françaises font face à des défis similaires liés aux changements climatiques. Des outils sont nécessaires pour guider les gestionnaires forestiers dans l'adaptation de leurs pratiques. La Suisse utilise une approche stationnelle basée sur les types de stations avec l'outil Tree App, tandis que l'Office National des Forêts, gestionnaire des forêts publiques françaises, se concentre sur les niches climatiques des essences avec l'outil Zoom 50. Malgré leurs différences, les deux approches visent à anticiper les changements climatiques et à adapter la gestion forestière en conséquence. Favoriser davantage d'échanges franco-suisses permettrait d’intéressantes synergies et apprentissages.
DOI: 10.3188/szf.2025.0044
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Saurer M., Gessler A., Grossiord C., Abegg M., Augustin S., Schaub M. (2025) Einfluss des Klimawandels auf Gesundheit und Vitalität. In A. Strauss & C. Fischer (Eds.), Waldbericht 2025. Entwicklung, Zustand und Nutzung des Schweizer Waldes. Bern; Birmensdorf: Bundesamt für Umwelt BAFU; Eidg. Forschungsanstalt für Wald Schnee und Landschaft WSL. 54-55.
• Die Häufung von warmen und trockenen Jahren wird zunehmend zu einer Belastung für den Wald. Selbst Baumarten, die bisher als trockenresistent galten, leiden darunter.
• Zwischenergebnisse des fünften Landesforstinventars zeigen eine Zunahme von geschädigten Bäumen. Hauptursachen sind Insekten und Krankheitserreger sowie Windwurf und Vitalitätsverlust nach Trockenheit.
• Das Bundesamt für Umwelt (BAFU) und die Eidg. Forschungsanstalt für Wald, Schnee und Landschaft (WSL) haben Werkzeuge zur Baumartenwahl im Klimawandel entwickelt. Wichtige Massnahmen sind die Förderung von Mischwäldern und die Erhöhung der genetischen Vielfalt der Wälder. -
Saurer M., Gessler A., Grossiord C., Abegg M., Augustin S., Schaub M. (2025) Impact of climate change on health and vitality. In A. Strauss & C. Fischer (Eds.), Forest Report 2025. Development, condition and use of Swiss forests. Bern; Birmensdorf: Federal Office for the Environment FOEN; Swiss Federal Institute for Forest, Snow and Landscape Research WSL. 54-55.
• As hot, dry years become more frequent, forests are placed under stress. Even tree species previously considered drought-resistant are suffering as a result.
• Interim results of the fifth National Forest Inventory show an increase in damaged trees. The main causes are insects and pathogens as well as windthrow and loss of vitality after drought.
• The Federal Office for the Environment (FOEN) and the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) have developed tools for selecting tree species in a changing climate. Key measures include promoting mixed forests and increasing the genetic diversity of forests. -
Saurer M., Gessler A., Grossiord C., Abegg M., Augustin S., Schaub M. (2025) Influence des changements climatiques sur la santé et la vitalité. In A. Strauss & C. Fischer (Eds.), Rapport forestier 2025. Évolution, état et utilisation de la forêt suisse. Berne; Birmensdorf: Office fédéral de l'environnement OFEV; Institut fédéral de recherches sur la forêt, la neige et le paysage WSL. 54-55.
• La multiplication d'années chaudes et sèches pèse de plus en plus sur la forêt. Même des essences réputées jusqu'ici résistantes à la sécheresse en souffrent.
• Les résultats intermédiaires du cinquième inventaire forestier national montrent une hausse des arbres endommagés, principalement en raison d'insectes, d'agents pathogènes, de chablis et de pertes de vitalité dues à la sécheresse.
• L'Office fédéral de l'environnement (OFEV) et l'Institut fédéral de recherches sur la forêt, la neige et le paysage (WSL) ont développé des outils pour un choix d'essences adaptées aux changements climatiques. La promotion de forêts mélangées et l'augmentation de la diversité génétique des forêts sont des mesures importantes. -
Saurer M., Gessler A., Grossiord C., Abegg M., Augustin S., Schaub M. (2025) Influenza del cambiamento climatico sullo stato fitosanitario. In A. Strauss & C. Fischer (Eds.), Rapporto forestale 2025. Evoluzione, stato e utilizzazione del bosco svizzero. Berna; Birmensdorf: Ufficio federale dell'ambiente (UFAM); Istituto federale di ricerca per la foresta, la neve e il paesaggio (WSL). 54-55.
• La frequenza di anni caldi e secchi sta diventando sempre più problematica per il bosco. Ne stanno risentendo anche le specie un tempo considerate resistenti alla siccità.
• I risultati intermedi del quinto Inventario forestale nazionale indicano un aumento degli alberi danneggiati,
soprattutto a causa di insetti e agenti patogeni ma anche per schianti da vento e perdita di vitalità in seguito alla siccità.
• L'Ufficio federale dell'ambiente (UFAM) e l'Istituto federale di ricerca per la foresta, la neve e il paesaggio
(WSL) hanno sviluppato degli strumenti per selezionare specie arboree adatte al cambiamento climatico. Le principali misure consistono nella promozione dei boschi misti e nell’incremento della loro diversità genetica. -
Schafer A., Suter Thalmann C.L., Schweier J., Thees O. (2025) Use of wood as a material and for energy. In A. Strauss & C. Fischer (Eds.), Forest Report 2025. Development, condition and use of Swiss forests. Bern; Birmensdorf: Federal Office for the Environment FOEN; Swiss Federal Institute for Forest, Snow and Landscape Research WSL. 120-123.
• Over the past decade, the end use of wood, including imports, has increased to around 11 million cubic metres per year.
• Use of wood as a material is tending to decline compared with its use as an energy source, but still accounted for around 41% in 2021.
• A large proportion of energy wood comes directly from forests. The quantity of such wood has increased by 20% in the past decade. The additional potential of forest energy wood that could be harnessed in the future is around 0.8 million cubic metres or 2.3 terawatt-hours of final energy per year. -
Schaub M., Beyeler S. (2025) Health and vitality. In A. Strauss & C. Fischer (Eds.), Forest Report 2025. Development, condition and use of Swiss forests. Bern; Birmensdorf: Federal Office for the Environment FOEN; Swiss Federal Institute for Forest, Snow and Landscape Research WSL. 43-55.
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Scherrer D., Abegg M., Jenni R., Thrippleton T. (2025) Caractère naturel. In A. Strauss & C. Fischer (Eds.), Rapport forestier 2025. Évolution, état et utilisation de la forêt suisse. Berne; Birmensdorf: Office fédéral de l'environnement OFEV; Institut fédéral de recherches sur la forêt, la neige et le paysage WSL. 80-81.
• Environ 20% des forêts sont inexploitées depuis plus de 50 ans. La plupart se trouvent dans les Alpes, où elles occupent 46% de l'aire forestière, suivies des Préalpes (36%). Sur le Plateau en revanche, 97% des forêts ont été exploitées au cours des 50 dernières années.
• Les peuplements peu naturels ont encore diminué. Mais les forêts en phase de sénescence, particulièrement précieuses pour la biodiversité, font encore défaut, surtout à basse altitude.
• Sur le Plateau, moins de 30% de l'aire forestière présente un caractère naturel. La part élevée de forêts peu naturelles accroît les risques, car ces peuplements sont plus vulnérables aux perturbations dues à la sécheresse et aux organismes nuisibles, dont la fréquence augmentera avec la progression des changements climatiques. -
Scherrer D., Abegg M., Jenni R., Thrippleton T. (2025) Naturalness. In A. Strauss & C. Fischer (Eds.), Forest Report 2025. Development, condition and use of Swiss forests. Bern; Birmensdorf: Federal Office for the Environment FOEN; Swiss Federal Institute for Forest, Snow and Landscape Research WSL. 80-81.
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Scherrer D., Abegg M., Jenni R., Thrippleton T. (2025) Naturnähe. In A. Strauss & C. Fischer (Eds.), Waldbericht 2025. Entwicklung, Zustand und Nutzung des Schweizer Waldes. Bern; Birmensdorf: Bundesamt für Umwelt BAFU; Eidg. Forschungsanstalt für Wald Schnee und Landschaft WSL. 80-81.
• Rund 20 % der Waldfläche wurden seit über fünfzig Jahren nicht mehr genutzt. Die meisten dieser Wälder befinden sich in den Alpen, wo sie 46 % der Waldfläche ausmachen, gefolgt von den Voralpen mit 36 %. Im Mittelland dagegen wurden 97 % der Waldfläche in den letzten fünfzig Jahren genutzt.
• Naturferne Bestände haben weiter abgenommen. Trotzdem fehlen insbesondere in den Tieflagen Wälder in späten Entwicklungsphasen, die für die Artenvielfalt besonders wertvoll sind.
• Im Mittelland sind weniger als 30 % der Waldfläche naturnah. Der hohe Anteil an naturfernen Wäldern birgt mehr Risiken, da diese Bestände anfälliger für
Störungen durch Trockenheit und Schadorganismen sind, die beim fortschreitenden Klimawandel häufiger auftreten werden. -
Scherrer D., Abegg M., Jenni R., Thrippleton T. (2025) Seminaturalità. In A. Strauss & C. Fischer (Eds.), Rapporto forestale 2025. Evoluzione, stato e utilizzazione del bosco svizzero. Berna; Birmensdorf: Ufficio federale dell'ambiente (UFAM); Istituto federale di ricerca per la foresta, la neve e il paesaggio (WSL). 80-81.
• Circa il 20 per cento delle aree boschive non viene utilizzato da oltre 50 anni. La maggior parte (46 % della superficie forestale) si trova nelle Alpi, seguite dalle Prealpi (36 % della superficie forestale). Sull’Altipiano, invece, il 97 per cento dei boschi negli ultimi 50 anni è stato utilizzato.
• I popolamenti fuori stazione si sono ulteriormente ridotti. Tuttavia, soprattutto a quote basse, mancano boschi in fase avanzata di sviluppo, così preziosi per la biodiversità.
• Sull'Altipiano meno del 30 per cento della superficie forestale è seminaturale. L'alta percentuale di boschi
non in stazione comporta maggiori rischi, in quanto i popolamenti sono più suscettibili alle perturbazioni
causate da siccità e organismi nocivi, destinati a verificarsi con maggiore frequenza con l’avanzare del cambiamento climatico. -
Schulz T., Ohmura T., Bütikofer J., Husistein M. (2025) Federal support for forestry. In A. Strauss & C. Fischer (Eds.), Forest Report 2025. Development, condition and use of Swiss forests. Bern; Birmensdorf: Federal Office for the Environment FOEN; Swiss Federal Institute for Forest, Snow and Landscape Research WSL. 114-115.
• Since 2016, federal funding has been geared towards climate change adaptation, including greater support for forest tending measures in areas not classed as protective forest.
• Federal funding for forest tending measures were raised on an exceptional basis in the period 2021–24, owing to stronger and more diverse climate impacts, particularly as a result of drought years.
• The Integral forest and wood strategy 2050 will enable better coordination of forest policy and wood resource policy, and places federal funding for forests on a new political footing. -
Schweier J., Kammerhofer A.W. (2025) Harvesting. In A. Strauss & C. Fischer (Eds.), Forest Report 2025. Development, condition and use of Swiss forests. Bern; Birmensdorf: Federal Office for the Environment FOEN; Swiss Federal Institute for Forest, Snow and Landscape Research WSL. 59-69.
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Suvanto S., Esquivel‐Muelbert A., Schelhaas M.‐J., Astigarraga J., Astrup R., Cienciala E., … Pugh T.A.M. (2025) Understanding Europe's forest harvesting regimes. Earth Future. 13(2), e2024EF005225 (20 pp.). https://doi.org/10.1029/2024EF005225
European forests are being shaped by active human use and management, and by harvesting of wood in particular. Yet, our understanding of how forests are harvested across Europe is limited, as the real harvest regimes are not well described by currently available data. Here, we analyse recent harvests, as observed in permanent plots of forest inventories in 11 European countries, totaling to 182,649 plots and covering all major forest types. We (a) characterize harvest regimes through the frequency and intensity of harvest events spatially across Europe, and (b) build models for the probability and intensity of harvest events at the plot-level and examine the links to potential drivers of harvest, including the pre-harvest forest structure and composition, climatic, topographic and socio-economic factors, and past natural disturbances. The results revealed notable variation in harvest regimes across Europe, ranging from high-frequency and low-intensity harvests in eastern Central Europe to low-frequency and high-intensity harvests in the north, with different strategies emerging in regions with similar total harvest rates. The harvest regimes were strongly driven by country-level variation, emphasizing the role of national-level factors. Pre-harvest forest properties were important drivers for the intensity of harvest, whereas the probability of harvest was more related to socio-economic factors and natural disturbances. The presented quantification of the forest harvesting regimes provides much needed detail in our understanding of the contemporary forest management practices in Europe, providing a baseline against which to assess future changes in management and strengthening the knowledge-base for decision-making on European level.
DOI: 10.1029/2024EF005225
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Wolf O., Temperli C. (2025) Forest ecosystem services. In A. Strauss & C. Fischer (Eds.), Forest Report 2025. Development, condition and use of Swiss forests. Bern; Birmensdorf: Federal Office for the Environment FOEN; Swiss Federal Institute for Forest, Snow and Landscape Research WSL. 66-67.
• Forests provide a variety of services that enhance the public’s safety and well-being. They provide protective, economic and welfare functions.
• The provision of forest ecosystem services incurs costs that have until now only been partially covered. These services can be valorised and monetised using indicators and expert-based valuation systems.
• Demand for forest ecosystem services will continue to rise as forests are increasingly used for recreational activity. This is likely to result in conflicts in the provision of different forest ecosystem services. -
Wolf O., Temperli C. (2025) Prestations forestières. In A. Strauss & C. Fischer (Eds.), Rapport forestier 2025. Évolution, état et utilisation de la forêt suisse. Berne; Birmensdorf: Office fédéral de l'environnement OFEV; Institut fédéral de recherches sur la forêt, la neige et le paysage WSL. 66-67.
• La forêt fournit une multitude de prestations qui contribuent à la sécurité et au bien-être de la population. Elle remplit les fonctions protectrice, économique et sociale.
• La fourniture de ces prestations occasionne des coûts qui n'ont été que partiellement couverts jusqu'ici. Des indicateurs et des systèmes experts d'évaluation permettent de les mettre en valeur et de les monétiser en vue de leur indemnisation.
• La demande de prestations forestières va encore augmenter au vu de l'évolution des loisirs en forêt. La fourniture de certaines d'entre elles créera probablement des conflits d'objectifs. -
Wolf O., Temperli C. (2025) Prestazioni del bosco. In A. Strauss & C. Fischer (Eds.), Rapporto forestale 2025. Evoluzione, stato e utilizzazione del bosco svizzero. Berna; Birmensdorf: Ufficio federale dell'ambiente (UFAM); Istituto federale di ricerca per la foresta, la neve e il paesaggio (WSL). 66-67.
• Il bosco fornisce una serie di prestazioni a beneficio della sicurezza e del benessere della popolazione. Adempie alle funzioni protettive, economiche e ricreative.
• Questi servizi causano costi finora solo parzialmente coperti. Per compensarli, è possibile valorizzarli e monetizzarli con l'ausilio di indicatori e sistemi di valutazione basati su opinioni di esperti.
• La domanda di prestazioni è destinata ad aumentare in considerazione delle crescenti attività del tempo libero che si svolgono nel bosco, ed è lecito attendersi anche conflitti tra i diversi obiettivi. -
Wolf O., Temperli C. (2025) Waldleistungen. In A. Strauss & C. Fischer (Eds.), Waldbericht 2025. Entwicklung, Zustand und Nutzung des Schweizer Waldes. Bern; Birmensdorf: Bundesamt für Umwelt BAFU; Eidg. Forschungsanstalt für Wald Schnee und Landschaft WSL. 66-67.
• 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. -
Strauss A., Fischer C. (Eds.) (2025) Forest Report 2025. Development, condition and use of Swiss forests. Bern; Birmensdorf: Federal Office for the Environment FOEN; Swiss Federal Institute for Forest, Snow and Landscape Research WSL. 159 p. https://doi.org/10.55419/wsl:37786
The Forest Report 2025 is the third publication of its kind, with previous versions appearing in 2005 and 2015. It is aimed at experts and anyone interested in forest and wood-related issues. The report provides an overview of the condition and development of Swiss forests over the past ten years and assesses the outlook for all relevant areas against the backdrop of advancing climate change. With a structure modelled on Forest Europe reports, the Forest Report sets out internationally comparable results and serves as a benchmark publication. It uses a broad range of data from long-term surveys to answer important questions for society, economic players and policymakers.
Der Waldbericht erscheint 2025 zum dritten Mal nach 2005 und 2015. Er richtet sich an Fachleute und an eine am Thema Wald und Holz interessierte Leserschaft. Der Waldbericht ist eine Gesamtschau über Zustand und Entwicklungen des Schweizer Waldes in den letzten zehn Jahren und gibt einen Ausblick für alle Themenbereiche im Hinblick auf den fortschreitenden Klimawandel. Mit seiner an den Berichten von Forest Europe orientierten Struktur liefert der Waldbericht international vergleichbare Ergebnisse und dient als Referenzpublikation. Er beantwortet anhand einer breiten Datenbasis aus Langzeiterhebungen wichtige Fragen für Gesellschaft, Wirtschaft und Politik.DOI: 10.55419/wsl:37786