Preselection of the regional demarcation

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).

Damage to young forest plants ≥10 cm in height and ≤11.9 cm in diameter at breast height (dbh), whereby browsing is only assessed on specimens ≤129 cm in height, – in eight classess. Reference: Field Survey (MID 127: Gipfeldürre, MID 174: Verbiss des Leittriebes, MID 977: Fegeschaden, MID 987: Schälschaden, MID 184: Krankheit; MID 183: Holzereischaden, MID 185: anderer Schaden)

Species of young forest plants ≥10 cm in height and ≤11.9 cm in diameter at breast height (dbh) with individual classes for the ten most important species or species groups in Switzerland («main tree species»), as well as the classes «other conifers», «other broadleaves» and «species not assessed in all inventories». The main tree species are spruce (Picea spp.), fir (Abies spp.), pine (Pinus sylvestris, P. nigra, P. strobus, P. mugo subsp. uncinata), larch (Larix spp. ), Arolla pine (Pinus cembra), beech (Fagus sylvatica), maple (Acer spp.), ash (Fraxinus spp.), oak (Quercus spp.) and chestnut (Castanea sativa). Reference: Field Survey (MID 1051: Jungwaldpflanzenart - Zählung)

Species of young forest plants ≥10 cm in height and ≤11.9 cm in diameter at breast height (dbh) with individual classes for the ten most important species or species groups in Switzerland («main tree species»), as well as the classes «other conifers», «other broadleaves» and «species not assessed in all inventories». The main tree species are spruce (Picea spp.), fir (Abies spp.), pine (Pinus sylvestris, P. nigra, P. strobus, P. mugo subsp. uncinata), larch (Larix spp. ), Arolla pine (Pinus cembra), beech (Fagus sylvatica), maple (Acer spp.), ash (Fraxinus spp.), oak (Quercus spp.) and chestnut (Castanea sativa). Reference: Field Survey (MID 1050: Jungwaldpflanzenart - nächste Pflanze)

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 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

Size of young forest plants ≥10 cm in height and ≤11.9 cm in diameter at breast height (dbh) – in three classes (two height classes and one dbh class). Reference: Field Survey (MID 507: Jungwaldklasse)

Size of young forest plants ≥10 cm in height and ≤11.9 cm in diameter at breast height (dbh) – in five size classes (two height and three dbh classes). Reference: Field Survey (MID 507: Jungwaldklasse)

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.

Area that meets the forest definition of the NFI, i.e. is «forest without shrub forest» or «shrub forest», and can be reached on foot.

Area accessible on foot that meets the NFI's definition of forest in both NFI4 (2009-2017) and NFI5 (2018-2026), i.e. was either «forest without shrub forest» or «shrub forest».

Forest of which less than two-thirds is covered with shrubs that can be accessed on foot.

Forest that was less than two-thirds covered with shrubs and accessible on foot in both NFI1 (1983-1985) and NFI2 (1993-1995).

Forest that was less than two-thirds covered with shrubs in the five inventories NFI1 (1983-1985), NFI2 (1993-1995), NFI3 (2004-2006), NFI4 (2009-2017) and NFI5 (2018-2026) and was accessible on foot.

Forest that was less than two-thirds covered with shrubs and accessible on foot in both NFI2 (1993-1995) and NFI3 (2004-2006).

Forest that was less than two-thirds covered with shrubs in both NFI3 (2004-2006) and NFI4 (2009-2017) and could be reached on foot.

Forest that was less than two-thirds covered with shrubs in both NFI4 (2009-2017) and NFI5 (2018-2026) and is accessible on foot.

Area that meets the NFI's definition of 'forest', i.e. is «a forest without shrub forest» or «a shrub forest».

Area that meets the NFI's definition of forest in both NFI4 (2009-2017) and NFI5 (2018-2026), i.e. was either «forest without shrub forest» or «shrub forest».

Forest that was less than two-thirds covered with shrubs in the four inventories NFI2 (1993-1995), NFI3 (2004-2006), NFI4 (2009-2017) and NFI5 (2018-2026), was accessible on foot and could be stocked, i.e. did not contain forest roads, recreational facilities, streams, avalanche paths, etc.