NFI Results

1993/95–2018/26

1993/95

1983/85–2018/26

1983/85

Altitude above sea level in classes of 200 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 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)

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.

Land cover classified into the two classes: «forest» (i.e. forest without shrub forest or shrub forest) and «non-forest» according to the forest definition of the NFI. Reference: Field Survey or, in if inaccessible – aerial photo interpretation

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).

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

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.

Division of Switzerland into 14 regions (2 in the Jura, 3 on the Plateau, 3 in the Pre-Alps, 5 in the Alps and 1 in the Southern Alps). The economic regions are a subdivision of the production regions according to economic-geographical criteria.

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.

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».

Accessible forest without shrub forest («a.f.w.s.f.»), i.e. forest that is less than two-thirds covered with shrubs and can be accessed on foot, which is situated in a forest that the cantons designated «protection forest» in 2022 according to the harmonised criteria of SilvaProtect-CH (Losey & Wehrli 2013).

Accessible forest, i.e. «forest without shrub forest» or «shrub forest» that can be accessed on foot and is situated in a forest that the cantons designated «protection forest» in 2022 according to the harmonised criteria of SilvaProtect-CH (Losey & Wehrli 2013).

Area designated in both the NFI4 (2009-2017) and the NFI5 (2018-2026) as «accessible forest», i.e. «forest without shrub forest» or «shrub forest» that can be accessed on foot and is situated in a forest that the cantons designated «protection forest» in 2022 according to the harmonised criteria of SilvaProtect-CH (Losey & Wehrli 2013).

Area designated in the five Inventories NFI1 (1983-1985), NFI2 (1993-1995), NFI3 (2004-2006), NFI4 (2009-2017) and NFI5 (2018-2026) as «accessible forest without shrub forest», a.f.w.s.f. i.e. «forest without shrub forest» that can be accessed on foot and is situated in a forest that the cantons designated «protection forest» in 2022 according to the harmonised criteria of SilvaProtect-CH (Losey & Wehrli 2013).

Area designated in both NFI4 (2009-2017) and NFI5 (2018-2026) as «accessible forest without shrub forest», a.f.w.s.f. i.e. «forest without shrub forest» that can be accessed on foot and is situated in a forest that the cantons designated «protection forest» in 2022 according to the harmonised criteria of SilvaProtect-CH (Losey & Wehrli 2013).

Forest, i.e. «forest without shrub forest» or «shrub forest», that is situated in a forest that the cantons designated «protection forest» in 2022 according to the harmonised criteria of SilvaProtect-CH (Losey & Wehrli 2013).

Area that, in both the NFI4 (2009-2017) and the NFI5 (2018-2026), conforms with the NFI's definition of «forest», i.e. «forest without shrub forest» or «shrub forest», and is situated in a forest that the cantons designated «protection forest» in 2022 according to the harmonised criteria of SilvaProtect-CH (Losey & Wehrli 2013).

Forest that is more than two-thirds covered with shrubs. Shrub forests include Alpine alder and pine forests in particular, but also hazel forests and similar stands. Reference: Field Survey (MID 576: Deckungsgrad Sträucher), and sometimes also aerial photo interpretation