Selection from the list of topics

2018/26

2009/17–2018/26

2009/17

2004/06–2018/26

2004/06

2004/06–2009/17

1993/95–2004/06

1993/95–2018/26

1993/95

1983/85–1993/95

1983/85–2018/26

Altitude above sea level in classes of 200 m. Reference: Digital height model DHM 25 from Swisstopo

Altitude above sea level in classes of 400 m. Reference: Digital height model DHM 25 from Swisstopo

Altitudinal vegetation belts in the system used in the guidelines for monitoring the sustainability and performance of protection forests (NaiS; Frehner et al. 2005) – in ten classes, whereby the classes «hyperinsubric», «colline» and «colline with beech» and «lower and upper montane» only occur in the Southern Alps (S), the classes «submontane», «lower montane», «upper montane» only in the Northern Alps (N) and the classes «high montane», «subalpine» and «upper subalpine» on both sides of the Alps. The information is based on the altitudinal vegetation belts determined by experts (accessible forest sample plots of NFI4 on the 1.4-km network; Arge Frehner et al. 2020), as well as on the altitudinal vegetation belts modelled for the period 1981-2010 (other sample plots; Zischg et al. 2021).

Altitudinal vegetation belts in the system used in the guidelines for monitoring the sustainability and performance of protection forests (NaiS; Frehner et al. 2005), reduced to three classes. The variable represents a simplification of the NaiS altititudinal vegetation belts in six classes (NAISHSTKOMB6KL) in which the class «hyperinsubric and colline» is mearged with «submontane» to form the class «hyperinsubric, colline, submontane», the class «lower and upper montane» with «high montane» to form the class «montane» and the class «subalpine» with «upper subalpine» to form the class «subalpine». The information is based on the altitudinal vegetation belts determined by experts (accessible forest sample plots of NFI4 on the 1.4-km network; Arge Frehner et al. 2020), as well as on the altitudinal vegetation belts modelled for the period 1981-2010 (other sample plots; Zischg et al. 2021).

Altitudinal vegetation belts in the system used in the guidelines for monitoring the sustainability and performance of protection forests (NaiS; Frehner et al. 2005), reduced to six classes. The variable represents a simplification of the NaiS altitudinal vegetation belts with ten classes (NAISHSTKOMB) in which the classes «hyperinsubric» and «colline» are merged with «colline with beech» to form the class «hyperinsubric and colline» and the class «lower montane» with «upper montane» and «lower/upper montane» to form the class «lower and upper montane». The information is based on the altitudinal vegetation belts determined by experts (accessible forest sample plots of NFI4 on the 1.4-km network; Arge Frehner et al. 2020), as well as on the altitudinal vegetation belts modelled for the period 1981-2010 (other sample plots; Zischg et al. 2021).

Aspect, classified into the following five classes: North, East, South, West and indeterminate. «Indeterminate» means that the slope is ≤10%. Reference: Field Survey (MID 191: Azimut der Exposition)

Aspect, classified into the following nine classes: North, North-East, East, South-East, South, South-West, West, North-West and indeterminate. «Indeterminate» means that the slope is ≤10%. Reference: Field Survey (MID 191: Azimut der Exposition)

Basal area of standing living trees and shrubs ≥12 cm in diameter at breast height (dbh) per hectare – in four classes. Reference: Field Survey (MID 60: Brusthöhendurchmesser, MID 62: Umfang)

Type of trees and shrubs ≥12 cm in diameter at breast height (dbh) in two classes (conifers or broadleaves). Reference: Field Survey (MID 50: Baumart)

Measure of inter-tree crowding of the tree crowns in a stand. Reference: Field Survey (MID 266: Schlussgrad)

Proportions of conifers and broadleaves making up the stand structure, classified according to their proportional basal areas into four classes: pure conifer forest: 91-100 % conifers, mixed conifer forest: 51-90 % conifers, mixed broadleaved forest: 11-50 % conifers and pure broadleaved forest: 0-10 % conifers. Reference: Field Survey (MID 265: Mischungsgrad)

Stage of stand development, defined by the dominant diameter at breast height (dbhdom = dbh of the 100 largest [thickest] trees per hectare). Young growth/thicket: dbhdom <12 cm, pole timber: dbhdom 12-30 cm, young timber: dbhdom 31-40 cm, medium timber : dbhdom 41-50 cm, old timber: dbhdom >50 cm, mixed: trees of different development stages, no development stage predominant or groups of different development stages covering < 500 m². Reference: Field Survey (MID 261: Entwicklungsstufe)

Diameter at breast height (dbh) of trees and shrubs ≥12 cm dbh - in classes of 4 cm. Reference: Field Survey (MID 60: Brusthöhendurchmesser, MID 62: Umfang)

Diameter at breast height (dbh) of trees and shrubs ≥12 cm dbh, classified in main diameter classes. Reference: Field Survey (MID 60: Brusthöhendurchmesser, MID 62: Umfang)

Diameter at breast height (dbh) of the trees and shrubs ≥12 cm dbh – in ten classes. Reference: Field Survey (MID 60: Brusthöhendurchmesser, MID 62: Umfang)

Indication as to whether introduced woody species (tree- or shrub-like neophytes) ≥12 cm in diameter at breast height (dbh) dominate the growing stock, i.e. account for at least 50% of the growing stock, classified into the three classes: «not dominated by introduced species», «dominated by introduced species other than black locust», «dominated by introduced, invasive black locust». Black locust is the only invasive introduced species that has been recorded separately in all NFI inventories to date. The classification as «invasive» corresponds to the publication «Alien species in Switzerland» of the Federal Office for the Environment (FOEN) from 2022 (UW-2220-E). Reference: Field Survey (MID 50: Baumart, MID 1018: Baumzustand, MID 60: Brusthöhendurchmesser, MID 62: Umfang)

Diameter at breast height (dbh) of the 100 largest (thickest) standing living trees and shrubs ≥12 cm dbh per hectare – in eight classes. Reference: Field Survey (MID 60: Brusthöhendurchmesser, MID 62: Umfang)

Mean diameter at breast height (dbh) of the 100 largest standing living trees ≥12 cm in diameter at breast height (dbh) per hectare – in five classes. Reference: Field Survey (MID 60: Brusthöhendurchmesser, MID 62: Umfang)

Combination of the 18 groups of NaiS site types, each with a similar objective for the main tree species (NAISGGROB20), into 10 large associations known as «forest formations». *As the characterisation of the site types in the NaiS-NFI project is on a small scale, it is possible that non-forest site types such as meadow, pasture and rock may be present in sample plots that are classified as «forest» in NFI. Similarly, «forest without shrub forest“ may also contain «shrub forest» site types.

Intensity of forest management, classified in three classes according to site quality and the time of the last treatment. Reference: Forest Service Survey (MID 607: Anzahl Jahre seit dem letzten Eingriff); modelled site quality (total growth performance according to Keller 1978)

Classification of forests into 12 classes («types») according to their development, structure and management. Unlike in the 17-class forest-type classification, in this 12-class classification all development stages (from young growth to timber) are subsumed in the class «uniform high forest». Reference: Field Survey (MID 255: Nutzungskategorie, MID 257: Waldtyp nach Aufnahmeanleitung LFI, MID 260: Waldform, MID 267: Bestandesstruktur, MID 261: Entwicklungsstufe)

Classification of forests according to their establishment, structure and management into 17 classes («types»). In contrast to the forest typology with 12 classes, the forest typology with 17 classes defines each development stage (young growth to timber) as an individual class. Reference: Field Survey (MID 255: Nutzungskategorie, MID 257: Waldtyp nach Aufnahmeanleitung LFI, MID 260: Waldform, MID 267: Bestandesstruktur, MID 261: Entwicklungsstufe)

Classification of the forest according to the forest decision and accessibility into the three classes «accessible forest without shrub forest», «inaccessible forest without shrub forest» and «shrub forest».

Type of forest in two classes: «forest without shrub forest» or «shrub forest». Reference: Field Survey (MID 816) or - if the forest is inaccessible – aerial photo interpretation

Land cover, classified as one of three categories: 'forest without shrub forest', 'shrub forest' and 'non-forest', based on the NFI forest definition. Reference: Field Survey (MID 816), or if inaccessible, aerial photo interpretation.

Classification of trees and shrubs ≥12 cm in diameter at breast height (dbh) into two classes according to their dbh: «not giant» (dbh ≤80 cm) or «giant» (dbh >80 cm). Reference: Field Survey (MID 60: Brusthöhendurchmesser, MID 62: Umfang)

Zones around groundwater wells and groundwater recharging facilities that are designated by the canton as in the public interest for protecting drinking water. How strict the property restrictions and/or management requirements are depends on the protection zone,. The variable reflects the protection zone categories applicable since 2016 in accordance with Art. 121 of the Waters Protection Ordinance (SR 814.201) and the status of designation by the cantons on 8 July 2022 (download of data from geodienste.ch).

Areas in higher and lower altitude zones classified according to the system used for altitudinal vegetation belts in the guidelines for monitoring the sustainability and performance of protection forests (NaiS; Frehner et al. 2005). The boundary between the higher and lower altitudes runs between the «upper montane» and «lower montane» levels on the Northern Alps and between the «high montane» and «upper/lower montane» levels to the Southern Alps. The information is based on the altitudinal vegetation belts determined by experts (accessible forest sample plots of NFI4 on the 1.4-km network; Arge Frehner et al. 2020), as well as on the altitudinal vegetation belts modelled for the period 1981-2010 (other sample plots; Zischg et al. 2021).

Located in/outside a groundwater protection zone. The cantons demarcate groundwater protection zones around groundwater wells and groundwater recharging facilities to protect drinking water where this is in the public interest. The indicator variable combines the various protection zone categories in force since 2016 in accordance with Art. 121 of the Waters Protection Ordinance (SR 814.201) into one class. Data status: 8 July 2022 (download from geodienste.ch).

Classification of trees and shrubs ≥12 cm in diameter at breast height (dbh) into the three classes: «introduced tree species», «native tree species» and «indeterminable and/or shrub species». Introduced tree species are tree species that have been intentionally or unintentionally introduced by humans into habitats outside their natural range. With this classification attribute, which is used in all inventories, the Japanese larch (L. kaempferi) and introduced arboreal willow species are not counted as introduced tree species, because they are recorded together with related native species in certain inventories. The Japanese larch (Larix kaempferi), for example, is grouped together with the European larch (L. decidua). Reference: Field Survey (MID 50: Baumart)

Introduced tree species ≥12 cm in diameter at breast height (dbh), recorded in all the Inventories, classified into the eight classes: Austrian pine (Pinus nigra), Weymouth pine (Pinus strobus), Douglas fir (Pseudotsuga menziesii), red oak (Quercus robur), non-native poplars (Populus [other introduced]), black locust (Robinia pseudoacacia), other introduced tree species (including sequoia, redwood, thuja, cedar, tree-of-heaven, horse-chestnut, tulip-tree). The remaining woody species (native tree species and all shrub species) are summarised in one class.

Correspondence between the actual proportion of conifers in a stand and the postulated natural proportion of conifers in the corresponding potential natural vegetation (PNV). Reference: NaiS site types, aggregated into groups with similar mixing and regeneration objectives («Gfein») according to the NaiS-NFI project (Arge Frehner et al. 2020) for the PNV; classification of the proportion of conifers according to the Kienast method; Field Survey (MID 50: Baumart, MID 60: Brusthöhendurchmesser, MID 62: Umfang)

Number of natural hazard processes that can occur simultaneously in forest designated «protection forest» by the cantons (as of 2022) according to the harmonised criteria of SilvaProtect-CH (as of 2022). The following four natural hazard processes can be considered: rockfall, avalanches, hillslope debris flows/landslides, channel processes. Reference: GIS data from the FOEN, 2022

Number of standing living trees and shrubs ≥24 cm in diameter at breast height (dbh) – in classes of 100. Reference: Field Survey (MID 60: Brusthöhendurchmesser, MID 62: Umfang, MID 1018: Baumzustand)

Number of standing living trees and shrubs ≥36 cm in diameter at breast height (dbh) – in classes of 100. Reference: Field Survey (MID 60: Brusthöhendurchmesser, MID 62: Umfang, MID 1018: Baumzustand)

Number of standing living trees and shrubs ≥12 cm in diameter at breast height (dbh) per hectare – in classes of 100. Reference: Field Survey (MID 60: Brusthöhendurchmesser, MID 62: Umfang, MID 1018: Baumzustand)

Classification of forest stands according to the dominant diameter at breast height (dbhdom), i.e. the 100 largest (thickest) standing living trees per hectare, as: «old timber stand» (dbhdom >50 cm) or «not old timber stand». Reference: Field Survey (MID 60: Brusthöhendurchmesser, MID 62: Umfang)

Forest ownership, classified according to the two categories: 'public' and 'private'. Reference: Forest Service Survey (MID 365: Eigentum)

Ownership of the forest, categorised according to the 7 types 'federal government', 'canton', 'municipality', 'citizens' community', 'corporation', 'individual private ownership' and 'company'. Reference: Forest Service Survey (MID 365: Eigentum)

Tree species group (conifers or broadleaves) with the larger basal area. For the calculation, the standing living trees and shrubs ≥12 cm in diameter at breast height (dbh) were taken into account. Reference: Field Survey (MID 1018: Baumzustand, MID 50: Baumart, MID 60: Brusthöhendurchmesser, MID 62: Umfang)

Main tree species with the largest basal area. For the calculation, the standing living trees and shrubs ≥12 cm in diameter at breast height (dbh) were taken into account. Reference: Field Survey (MID 1018: Baumzustand, MID 50: Baumart, MID 60: Brusthöhendurchmesser, MID 62: Umfang)

Type of the most important forest function relevant for managing the forest according to forest plans or an assessment by the local forest service during NFI4 (2009-2017). Reference: Forest Service Survey (MID 911: Vorrangfunktion 2)

Type of the most important forest function relevant for management according to forest plans or an assessment by the local forest service during NFI5 (2018-2026). Reference: Forest Service Survey (MID 911: Vorrangfunktion 2)

Presence of the primary function «nature and landscape conservation», classified into the four classes: «landscape protection», «nature conservation», «game protection» or «other» according to forest plans or an assessment by the local forest service during NFI5 (2018-2026). Reference: Forest Service Survey (MID 911: Vorrangfunktion 2)

Presence of the primary function: «nature conservation» according to forest plans or an assessment by the local forest service during NFI5 (2018-2026). Reference: Forest Service Survey (MID 911: Vorrangfunktion 2)

Proportion of conifers in the basal area of standing living trees and shrubs ≥12 cm in diameter at breast height (dbh) – in four classes. Reference: Field Survey (MID 60: Brusthöhendurchmesser, MID 62: Umfang)

Area in/outside a forest that provides protection against avalanches which the cantons designated «protection forest» according to the harmonised criteria of SilvaProtect-CH in 2022. Reference: GIS data from FOEN, 2024

Area in/outside a forest that provides protection against channel processes which the cantons designated «protection forest» according to the harmonised criteria of SilvaProtect-CH in 2022. Reference: GIS data from FOEN, 2022

Area in/outside a forest that provides protection against hillslope debris flows/landslides which the cantons designated «protection forest» according to the harmonised criteria of SilvaProtect-CH in 2022. Reference: GIS data from FOEN, 2023

Area in/outside a forest that provides protection against rockfall processes which the cantons designated «protection forest» according to the harmonised criteria of SilvaProtect-CH in 2022. Reference: GIS data from FOEN, 2025

Area inside/outside the protection forest that the cantons had designated in 2022 according to the harmonised criteria of SilvaProtect-CH (Losey & Wehrli 2013). In 2022, Canton Aargau had not yet designated its protection forest. Reference: GIS data from FOEN, 2022

Terrain topography - in five classes. Reference: Field Survey (MID 192: Relief)

Type of forest reserve («natural forest reserve», «special forest reserve“ or «other forest»), based on the forest reserves as designated by the cantons (as of 2023) and the forest/non-forest decision of the respective Inventory. Reference: GIS data from FOEN, 2023, and Field Survey (MID 816) or – if the forest is inaccessible – aerial photo interpretation

Production capacity of the site in kilograms per hectare and year based on the total mean increment (TMI) according to Keller (1978) - in four classes. Low: TMI ≤1500 kg/(ha/year), moderate: TMI 1501-3000 kg/(ha/year), good: TMI 3001-4500 kg/(ha/year), very good: TMI >4500 kg/(ha/year).

Slope in classes of 20%. Reference: Digital height model DHM 25 from Swisstopo

Slope in classes of 40%. Reference: Digital height model DHM 25 from Swisstopo

Age of the stand – in classes of 20 years. Reference: Field Survey (MID 264: Bestandesalter)

Age of the stand – in classes of 40 years. Reference: Field Survey (MID 264: Bestandesalter)

Density of a stand – in four classes. The Stand Density Index (SDI) is calculated on the basis of the number of stems per hectare of trees and shrubs ≥12 cm in diameter at breast height (dbh) and the mean diameter. Reference: Field Survey (MID 60: Brusthöhendurchmesser, MID 62: Umfang, MID 1018: Baumzustand)

Mechanical resistence of a stand to abiotic and biotic stresses within the next 10 to 20 years – in three classes. Reference: Field Survey (MID 310: Gesamtstabilität)

Vertical structure (stratification) of a stand, defined on the basis of the degrees of cover of the upper, middle and lower layers. Reference: Field Survey (MID 267: Bestandesstruktur)

Number of years since the last silvicultural treatment – in classes of ten years. Silvicultural treatments include harvesting and tending interventions, planting and afforestation, as well as sanitary and safety interventions. Reference: Forest Service Survey (MID: 607: Anzahl Jahre seit dem letzten Eingriff)

Number of years since the last silvicultural treatment in classes of five or ten years. Silvicultural treatments include harvesting and tending interventions, planting and afforestation, as well as sanitary and safety interventions. Reference: Forest Service Survey (MID: 607: Anzahl Jahre seit dem letzten Eingriff)

Sample plots with/without extensive traces of forest fire (e.g. burnt ground vegetation, charred parts of tree or soil layers) on the interpretation plot (50 × 50 m). Reference: Field Survey (MID 203: Spuren von Waldbrand)

Sample plots with/without traces of landslides (e.g. a toe or crack, and trees leaning uphill) on at least 100 m² of the interpretation area (50 × 50 m). Reference: Field Survey (MID 193: Rutschung)

Sample plots with/without traces of livestock pasturing in the relevant stand on the interpretation area (50 × 50 m). Traces could be: presence of pasturing livestock, faeces, fresh tracks, resting places, torn hairs and traces of browsing or fraying, and indication of the livestock class in the case of pasturing. Reference: Field Survey (MID 204: Beweidungsart)

Sample plots with/without current traces of rockfall on the interpretation plot (50 × 50 m). Reference: Field Survey (MID 195: Steinschlag)

Sample plots with/without traces of snow movement, i.e. snow creep, snow sliding or avalanches on the interpretation area (50 × 50 m). Reference: Field Survey (MID 202: langsame Schneebewegung und MID 400: Lawinenspuren)

Classification of trees and shrubs ≥12 cm in diameter at breast height (dbh) as standing or lying, and as living or dead. Reference: Field Survey (MID 58: Bemerkungen, MID 1018: Baumzustand)

Type of trees and shrubs ≥12 cm in diameter at breast height (dbh). The three most common species or species groups in Switzerland (spruce - Picea spp.; fir - Abies spp.; beech - Fagus sylvatica) are in individual classes, while the remaining species are classified as «other conifers» or «other broadleaves». Reference: Field Survey (MID 50: Baumart)

Type of trees and shrubs ≥12 cm in diameter at breast height (dbh) – in 56 classes. The species (or species groups) not explicitly listed are subsumed in the classes «other conifers», «other broadleaved trees» and «other shrubs». Reference: Field Survey (MID 50: Baumart)

Classification of trees and shrubs ≥12 cm in diameter at breast height (dbh) into standing or lying. Reference: Field Survey (MID 58: Bemerkungen, MID 1018: Baumzustand)

Type of stand establishment, with natural and artificial regeneration distinguished. Reference: Field Survey (MID 275: Verjüngungsart)

Demarcation of Switzerland into five regions (Jura, Plateau, Pre-Alps, Alps and Southern Alps) with relatively uniform growth and timber production conditions. The production regions were established by the Federal Office of Forestry long before the first National Forest Inventory (NFI1, 1983-1985). With a small exception along Lake Geneva, the boundaries of the production regions still follow the municipal boundaries of the time. Unlike the NFI, the Forestry Statistics of the Federal Statistical Office don't use the production regions as demarcation but rather the forestry zones, whose boundaries are somewhat different.

Demarcation of Switzerland used in NFI for protection forest analyses. The six protection forest regions were derived from the economic regions by combining individual regions according to natural and statistical criteria.

Regional demarcation with the cantons as a unit, with the two half-cantons, Basel-Land and Basel-Stadt, combined into one canton for statistical reasons.

Demarcation of Switzerland into six regions with similar flora and fauna. The six regions correspond to the basic categories in the publication «The Biogeographical Regions of Switzerland», which was published by FOEN in 2022.

Regional demarcation with the forest districts as a unit. This variable was implemented in the year 2024 and is based on a survey with the cantonal forest services in the years 2022/2023.