# Forest Altitudinal Zones and their Change with Climate Change A thematic map of the Atlas of Switzerland, the national atlas published by ETH Zurich. The map is drawn in the browser; this file describes it and lists its variants and links, but not the data values shown on the map. - Map: https://atlasderschweiz.ch/en/theme/forest-altitudinal-zones-and-their-change-with-climate-change/ - Short title: Forest Altitudinal Zones and Climate Change - Map id: 1007 - Categories: Landscape and Space › Landscapes/Habitats › Forest and trees - Keywords: Climate change, Forest - Published: 2022-07-20 - Last revised: 2023-04-05 - Content language: English - Other languages: [Deutsch](https://atlasderschweiz.ch/de/thema/waldhoehenstufen-und-ihre-veraenderung-mit-dem-klimawandel.md), [Français](https://atlasderschweiz.ch/fr/theme/etages-de-vegetation-forestiere-et-leur-modification-avec-le-changement-climatique.md), [Italiano](https://atlasderschweiz.ch/it/tema/fasce-altitudinali-forestali-e-loro-variazione-con-il-cambiamento-climatico.md) ## Description *Forest altitudinal zones* Plants and trees – and by extension forests – grow where their physiological properties allow and where they will not be ousted by competition. For this reason, plants of a certain species tend to grow in places with similar temperatures, availability of water or soil conditions, for example, and where these are hospitable for the plant in question. Many species only occur within certain altitude ranges because temperature decreases as the altitude above sea level increases. As such, vegetation is organised into altitudinal zones. Highly variable local factors such as cold air currents, exposure or even various soil attributes do, however, lead to deviations of several hundred metres in altitude. The altitudinal zones of woodland are defined based on the ecological behaviour of various tree species and according to structural properties of the tree population. In Switzerland, the major species of tree for determining altitudinal zones are linden, oak, chestnut and holly at the lower levels; beech, fir, pine and spruce at medium altitudes; and larch and Swiss stone pine at the tree line. In southerly aspects, the transitions between zones are usually higher up than in northerly aspects due to the warming effect of the sun. The boundaries are also higher in inner Alpine regions than at the edge of the Alps or in the lowlands as mountains generally experience greater warming. The lowest zone, known as the colline zone, extends to up approximately 600 m above sea level in the north and 900 m above sea level in the south. From this point up to approximately 1200 m or 1700 m above sea level, there is the montane zone. The upper boundary of the adjoining subalpine zone is located in Jura at the highest peaks (approximately 1600 m above sea level) or between 1900 m and 2400 m above sea level in the Central Alps. This corresponds to the climatic tree line. Especially in autumn – when the leaves of deciduous trees turn red at lower altitudes whilst the evergreen trees remain green at higher altitudes – it is easy to observe the woodland altitudinal zones. *Impact of climate change* Climate change is affecting the species of tree and thereby the woodland altitudinal zones in various respects. The most significant of these are the changes in precipitation patterns and the temperature increase. With the rising temperatures, the zones hospitable to particular species of tree are also climbing. As such, the woodland altitudinal zones are moving upwards. However, as the higher regions are only limited in extent, it is only possible to evade this partially. In particular, the highest altitude woodland types are disappearing as a result – in spite of the fact that they are beginning to extend into as yet unforested regions (rising of the tree line) – faced with the advance of climate change. The lower-lying altitude zones, by way of contrast, are experiencing an enormous expansion in area. *Modelling and visualisation method* This map represents the woodland altitudinal zones based on models for the three time periods 1975, 1995 and 2085 by the Federal Office for the Environment (FOEN). In creating it, the data were slightly simplified in the interest of achieving a more elegant representation, though without impacting the overall impression. In order to take into account uncertainties regarding the future development of climate change, two scenarios are considered for 2085. These are based on climate models that make different assumptions regarding temperature increase and precipitation change. The “moderately dry” scenario assumes average warming of 1.8°C (northern Switzerland) or 2.3°C (southern Switzerland) and a reduction in precipitation of 4.0% (northern Switzerland) or 0.5% (southern Switzerland) for the months of April to August, which are climatically relevant to the growth of trees. The second and more drastic “dry” scenario assumes average warming of 4.4°C (northern and southern Switzerland) and a reduction in precipitation of 17.0% (northern Switzerland) or 24.9% (southern Switzerland) and leads to correspondingly more dramatic changes. Both future scenarios for 2085 anticipate significant shifts in area in the woodland altitude zones. This is based on the assumption that a new area would be characterised by climatic conditions broadly similar to those of the current area and that the woodland ecosystems that occur there would therefore roughly correspond to today’s. However, the big question of whether all species will be able to migrate from their old home territory to new ones in good time remains unresolved. At higher altitudes in particular, appropriate soils would also have to form. In this regard, there is a great deal of uncertainty as to what woodland will actually look like in the future woodland altitudinal zones. ## Sources - Huber et al. (2019): [Modellierung der Vegetationshöhenstufen und der Areale von Buche und Tanne für die Schweiz](http://www.monikafrehner.ch/joomla/SZF%20170%20%282019%29%2006_Huber.pdf) - [RCP-Szeanrien](https://wiki.bildungsserver.de/klimawandel/index.php/RCP-Szenarien). Bildungswiki Klimawandel - Frehner et al. (2005): Nachhaltigkeit und Erfolgskontrolle im Schutzwald. Bundesamt für Umwelt - Baltisberger & Nyffeler (2018): [Höhenstufen](http://www.balti.ethz.ch/pdf/Hoehenstufen.pdf) - Urmi (2011): [Höhenstufen](https://www.swissbryophytes.ch/index.php/de/mehr-ueber-moose/gebiet/die-vegetation). Swissbryophytes ## Data sources - (2019): [Modellierung Waldhöhenstufen](https://map.geo.admin.ch/?lang=en&topic=ech&bgLayer=ch.swisstopo.pixelkarte-farbe&layers=ch.bafu.wald-vegetationshoehenstufen_2085_weniger_trocken,ch.bafu.wald-vegetationshoehenstufen_1995,ch.bafu.wald-vegetationshoehenstufen_1975,ch.bafu.wald-vegetationshoehenstufen_2085_trocken&layers_opacity=0.75,0.75,0.75,0.75&E=2524340.78&N=1238579.51&zoom=1). BAFU/OFEV/UFAM/FOEN ## Data owners - [FOEN](https://www.bafu.admin.ch/bafu/de/home/amt/kontakt-und-standort-des-bafu.html) ## Citation The terms of use ask to name the Atlas of Switzerland and the data owners, and to keep the source references in exports, screenshots and embeds. Cite the map as: > Atlas of Switzerland (2023): Forest Altitudinal Zones and their Change with Climate Change. ETH Zürich. Map data © FOEN. https://atlasderschweiz.ch/en/theme/forest-altitudinal-zones-and-their-change-with-climate-change/ ## Variants The map has 4 variants. Levels: variant → time. The `u` value of a variant selects it in the links below. - 1975 - 1975: `u=AEIAAAEx` (default) - 1995 - 1995: `u=ABUAAAEy` - 2085: less dry - 2085: `u=A6sAAAEz` - 2085: dry - 2085: `u=A6sAAAE0` ## Links Replace `{u}` with the `u` value of a variant above, or leave out `u={u}` for the default variant. The map opens at its full extent; a link cannot set the map position. - Map: https://atlasderschweiz.ch/en/theme/forest-altitudinal-zones-and-their-change-with-climate-change/?u={u} - Short link, stays valid when the title changes: https://atlasderschweiz.ch/en/t/1007/?u={u} - Side by side with another map: https://atlasderschweiz.ch/en/comparison/?lt=1007&lu={u}&rt={id of the other map}&ru={u of the other map, or leave out} Embed in another website (allowed by the terms of use, as long as the source references stay visible): ```html ``` In the embed URL, `dm` sets what is shown: `e` the map with its title bar (default), `p` also the values of an object clicked on the map, `m` only the map with a button that opens it in the atlas. `ig=1` (default) lets the map react to scrolling and dragging only after a click into it, `ig=0` right away. The size can be changed in `style`. For the use and citation of maps and data, see the [terms of use](https://atlasderschweiz.ch/en/terms-of-use/).