Ministerium für Ländlichen Raum und Verbraucherschutz Baden-Württemberg
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Alder and alder-ash forests are so called "azonal" forest communities. This means that the soil has a larger influence than the climate. These forests are common in the bottom of valleys, at lower slopes and in swales with permanent rivulets and lateral rivulets. They can be found in areas with moist to wet soils.
Black Alder (Alnus glutinosa) and Common Ash (Fraxinus excelsior) are the predominant tree species.
Two different soil types are specified:
Alder-ash forests are normally stream-accompanying forests. The tree and herbaceous layer acts as the connection between land and water.
This article of the ONF describes the forest communities of the alder-forests and the alder-ash-forests of the Vosges, the ecological functions of these forests and the threats posed by human impacts. Some recommendations for the management of these forests are also given.
|Fig. 1: Black Alder riparian forest (Netzenbach vallée de la Bruche – Alsace).||Fig. 2: Alder forest on the lower slopes (Schirmeck – Alsace). (Fotos: ONF)|
Alder or alder-ash forests occur over the entire Vosges (Bunt-sandstone, crystalline rock, Alsatian Jurassic rock) from colline level up to more than 1000 meters.
Their presence differs depending on the type of substrate and the type of water supply (flooding, high water, stream or standing water).
Following a survey of wet lands and streams in the public forest of the Vosges it was possible to quantify the frequency of occurrence:
The defined objective is the preservation of the alder and alder-ash forests as well as the regeneration of damaged habitats. Production is secondary in such forest communities.
Three measures have to be supported:
|Fig. 3: Swamp-Alder Forest (Northern Vosges – Alsace). (Foto: ONF)|
The classification of the alder and alder-ash forest
can, depending on the water supply, be carried out based on their function. The
forests are very complex and multifaceted forest communities. So far no
detailed descriptions of their appearance are available (work in progress: summary
of the forest types of the Alsace
+ identification key). In montane areas they occur only in small areas in non-specific
associations closely connected to nearby forest communities.
Leaflets about the Plant Sociology Classification can be downloaded
as PDF documents via the following links:
|Purple Small Reed||Calamagrostis canescens (Swamp-Alder Forest, Swamp…)|
|Bog Arum||Calla palustris (Swamp-Alder Forest)|
|Small Enchanter's Nightshade||Circaea alpina (Alder-Ash Forest)|
|Royal Fern||Osmunda regalis (Swamp-Alder Forest)|
|European White Elm||Ulmus laevis (Alder-Ash Forest)|
|Crested Wood Fern||Dryopteris cristata|
|Remote Wood Fern||Dryopteris remota|
|Marsh Fern||Thelypteris palustris|
|Yellow Star-of-Bethlehem||Gagea lutea|
|Ostrich Fern||Matteuccia struthipteris (montane Alder-Ash Forest)|