Swiss Alpine forest communities

In the high-montane and subalpine zone with its typical site characteristics, specific forest communities occur. Every forest community is characterized by its forest-building tree species (link to the glossary) and by some characteristic herbs, ferns and mosses.

Only a few specialized tree species climb to the high-montane and subalpine zone and build forest communities there. Some single pioneer trees occasionally occur in these zones as well, but they are not forest-building tree species. We call these occasionally occurring tree species (link to the glossary). The forest limit is formed by coniferous tree species of the subalpine zone in most regions of the Swiss Alps. Only in a few regions can we also find stands of deciduous trees at the forest limit.

Due to the mixture of tree species in a forest we differentiate three types of forests:

• Mixed coniferous trees forests (link to the glossary)
• Mixed coniferous and deciduous trees forests (link to the glossary)
• Single-species forests (link to the glossary)

In the list below, the most important forest-building trees of the high-montane and subalpine zone are described. The occurrence of these tree species depends on different altitudinal and physiological limits. Some tree species grow as a kind of dwarf shrubs at the so called Krummholz limit.
 

Fagus sylvatica (beech):

• Climbs up to the high-montane zone of the Northern Alpes at about 1600m
• Occurs in the Northern Alps and in the Jura mountains at the tree limit on single sites only
• Regionally forms the timberline in the Southern Alps (Ticino) at c. 1600m where due to the humid insubric climate and to the plant geography (line Bellinzona-Maggia valleys), the highly competitive Picea abies (Norway spruce) does not grow.

1 - Beech (Fagus sylvatica) and silver fir (Abies alba) forming a high-montane forest in the Northern Alps and Jura mountains (Switzerland).

Abies alba (silver fir):

• Forest limit at c. 1700m, tree limit at c. 1900m
• Never forms the timberline in the European Alps
• Mostly occurs together with other tree species in mixed forests
• Likes climate conditions with humid air

2 - Silver fir (Abies alba) - Norway spruce (Picea abies) forest in the Swiss Plateau (Canton of Aargau, Switzerland).

Pinus sylvestris (Scots pine):

• Very wide-ranged coniferous tree species which climbs to the high-montane zone at about 1700m
• Does not form the timberline in the Swiss Alps
• Competitive in warm, dry places as well as on wet and acid soils
• Forms open, single-species forests in continental regions

3 - Montane Scots pine (Pinus sylvestris) forest (Weissenstein, Southern Tyrolian Alps).

Picea abies (Norway spruce):

• Forms wide-ranged, single-species forests
• Forms the timberline in the Prealps and in the less continental Central Alps
• Forest limit c. 2100m, tree limit c. 2300m

4 - Subalpine Norway spruce (Picea abies) forest during winter (San Bernardino, Lago Dosso, Grisons, Switzerland).

Larix decidua (European larch):

• Forms the inner and Southern Alpine timberline
• Likes very continental, dry, sunny climate
• High frost resistance
• Climbs to the highest forest sites (tree limit c. 2500m)

5 - Group of European larches (Larix decidua) growing in the subalpine zone (Val Müstair, Grisons, Switzerland).

Pinus cembra (Alpine stone pine):

• Forms the inner Alpine timberline in many cases together with Larix decidua (European larch)
• Likes very continental, dry, sunny climate
• High frost resistance
• Forest limit c. 2370m, tree limit c. 2450m

6 - Alpine stone pine (Pinus cembra) forming a subalpine coniferous forest together with European larch (Larix decidua) in yellow autumn coloration (Val di Camp, Grisons, Switzerland).

Pinus mugo ssp. uncinata (mountain pine):

• Occurs in single-species forests
• Competitive on poor, dry or wet soils
• High frost resistance
• Forms the timberline in the Central Alps (e.g. Swiss National Park)

7 - Mountain pine (Pinus mugo ssp. uncinata) forming subalpine single species forests (Ofenpass, Grisons, Switzerland).

Pinus mugo ssp. mugo (dwarf mountain pine):

• Forms the Krummholz limit in the Central Alps
• Grows mainly on poor, dry or wet soil
• Typical on screes of calcareous or dolomitic rocks
• Occurs in high altitudes instead of Pinus mugo ssp. uncinata (mountain pine)

8 - Dwarf pine (Pinus mugo ssp. mugo) building the krummholz zone at the tree limit on dolomitic screes (Munt la Schera, Grisons, Switzerland).

In the following interactive animation, use the above clues to create one or more examples of the 8 most important forest communities in the upper-montane and subalpine zone of the Swiss Alps.

Click on one or more trees (symbols) from the available species to "plant" it in the box below, if you think that it could be a forest-building tree in the community you are creating. Try to choose realistic combinations.

Clicking on the trees within the box will remove them from the community. Click the check button to see if your self-created community is possible and get more information about it. Click the reset button to try again.  

29 August 2011
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