Wet Woodlands

Importance for wildlife

Wet woodlands provide diverse conditions which support a wide range of plants, invertebrates, birds and mammals. The high humidity and presence of damp bark support a range of mosses and liverworts. An extremely large number of invertebrates are associated with alder, birch and willow and fallen dead wood in streams or fens provides specialised habitats.

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Factors affecting habitat in Suffolk

• Loss of woodland through restoration to other conservation land uses, such as fen or reedbed.
• Poor management changing the structure, scrub invasion, a lack of regeneration and loss of diversity.
• Unusual flooding events leading to loss of water quality and changes in fauna and flora composition, occasional flooding is part of the normal cycle that the habitat is adapted to cope with.
• Colonisation by invasive non-native species such as Himalayan Balsam.
• Removal of moss-covered trees, deadwood, old or diseased trees, removing important habitats.
• Water pollution and nutrient enrichment from agricultural run-off.
• Water abstraction and drainage lowering the water table.

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Habitat management advice

• Maintain ‘naturalness’ of woods where possible, avoiding sudden and drastic modifications.
• Leave any wet areas such as streams and ponds undisturbed.
• Manage woodlands according to the UK Forestry Standard
• The felling of wet woodland trees may need approval from the Forestry Commission

Notes

National Vegetation Classification is a common standard developed for nature conservation agencies containing a comprehensive classification and description of the plant communities of Britain, systematically named and arranged and with standardised descriptions for each.

National Vegetation Classification (NVC) stand types found in Suffolk

1. W1: Grey Willow – common marsh-bedstraw woodland Salix cinerea – Gallium palustre woodland
2. W2: Grey Willow – downy birch – common reed woodland Salix cinerea – Betula pubescens – Phragmites australis woodland
3. W4c: Downy birch – purple moor-grass woodland Sphagnum sub-community Betula pubescens – Molinia caerulea woodland Sphagnum sub-community
4. W5: Alder – greater tussock sedge woodland Alnus glutinosa – carex paniculata woodland
5. W6: Alder – common nettle Alnus glutinosa – Urtica dioica woodland

These stands are found on flood plains as successional habitats on fens and mires, along rivers and streams, by flushes and in peaty hollows. The wet woodlands on the boulder clay in Suffolk tend to be considered as part of the ash – field maple – dog’s mercury woodland Fraxinus excelsior – Acer campestre – Mercurialis perennis woodlands (W8 in the NVC) and are excluded from this factsheet.

The strongholds for wet woodlands are Suffolk Broads, the Waveney and Little Ouse Valleys and the Suffolk River Valleys ESA.

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Vision for Suffolk

1. Improve knowledge of extent and quality of wet woodland.
2. Maintain the existing extent of wet woodland to ensure no net loss.
3. Re-create wet woodland as opportunities arise.
4. Encourage the restoration and improvement of degraded wet woodland.

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Where to find further information

• Buglife – advice on managing BAP habitats
• Buglife – Notable invertebrates (pdf)
• Forest Research – The Management of semi-natural Woodlands (pdf)
• JNCC – Habitat Description (pdf)
• JNCC – The National Vegetation Classification (NVC)
• MAGIC website – interactive mapping information including designations
• Making Space for Nature, a Review of England’s Wildlife Sites and Ecological Network 16 Sep 2010. Chaired by Professor Sir John Lawton CBE FRS. Defra website (pdf)
• Natural England – Traditional orchards information notes
• Natural Environment White Paper June 2011 – The Natural Choice: securing the value of nature (pdf)
• Peterken, G.F., 1981 Woodland Conservation and Management. London: Chapman and Hall.
• Rackham, O. 1980 Ancient Woodland. London: Arnold.
• Suffolk Wildlife Trust – Habitats Explorer
• Woodland Trust – Wet Woodland

* all the links marked (pdf) have been gathered into an Issuu stack

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Images: 

• Alder Carr at Syleham Road
• Siskin by Neil Rolph (Flickr)
• Chicken of the woods on Alder by Paul Kitchener (Flickr)
• Otter by Neil Rolph (Flickr)

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