Atlantic hazel - habitat management

Note: For more detail and advice about the different management options for Atlantic hazel, take a look at chapter 5    (examples) and chapter 6    (advice) of the free Scottish Natural Heritage publication 'Atlantic Hazel'.

Individual hazelwoods have different histories of management and therefore have different management recommendations. The main hazelwood types are:

• Closed canopy, multi-stemmed stands of pure hazel
• Scattered stools in pasture (a broad, catch-all category)
• Antique, veteran hazel stools
• Hazel in woodlands (including ravines)

Further details of these four types and specific management requirements are given in the above 'Atlantic Hazel' chapter downloads. The rest of this page provides a summary of the main management activities that can have a negative and positive impact on Atlantic hazel biodiversity.

NEGATIVE MANAGEMENT

Coppicing: Disrupts the natural dynamics of hazel stools that are important for biodiversity. All lichens, fungi and bryophytes growing on the hazel and removed with the cut stems will die. Coppicing destroys ecological continuity, resulting in loss of species dependent on this, e.g. mostly lichens of the smooth bark Graphidion community, but also the larger, leafy-lobed lichens of the Lobarion community. Coppicing removes shade and reduces humidity to the detriment of species that rely on these conditions, e.g. Atlantic bryophyte. Fungal diversity is know to be lower in coppiced hazel.

Continuous heavy grazing: Disrupts the natural dynamics of hazel stools that are important for biodiversity. It also leads to loss of habitat structure and ultimately of entire hazel stools. Natural regeneration by producing new shoots from the base of the stool is constantly thwarted by grazing. Hazel stools develop unstable growth forms on few stems, with an unnaturally elevated canopy, prone to wind-blow. Ground flora is trampled and poached while excessive dunging producing nutrient-enriched conditions. Species dependent on continuity of habitat conditions within an old-growth stand may be lost.

Long-term exclosures: Can disrupt natural processes of the habitat by excluding occasional light grazing; this leads to a closing-in of glades and build up of rank vegetation. The gladed edges to hazel stands are compromised and lost to dense, thicket regeneration.

'Scrub' clearance: Destroys the habitat.

Unsuitable siting of cattle feeding stations: Causes localized intensive use of areas that results in ground flora being trampled and poached. Excessive dunging produces unnaturally high levels of nutrient-enrichment that is harmful to biodiversity.

Rhododendron ponticum : Invasion by this non-native evergreen shrub results in a general loss of biodiversity through the effects of over-shading, and toxic leachate from leaf-litter.

POSITIVE MANAGEMENT

Light seasonal grazing: Light grazing will ensure glades are kept open, an important habitat feature that benefits a range of wildlife within the hazel habitat; there may be some slight damage to stems, and some basal regeneration will be browsed, but the level should be sustainable.

Re-introduction of grazing into hazel stands that were formerly fenced to exclude all grazing: This must be a gradual process, i.e. domestic animals must have access to easy bite as well as struggling through thickets, where animal welfare may be compromised. The aim would be to restore glades within a stand that had closed up into thicket regeneration.

Encourage hazel expansion: Managing grazing to enable isolated hazel stands or widely spaced clumps to form an integrated habitat (without compromising glade or woodland edge habitats), needs to be carefully managed.

Planting hazel to replenish a severely reduced habitat: Using hazelnuts locally sourced, and carefully propagated in a nursery (protected from mice and vole predation), and planted out as well-established saplings, initially protected by Tuley tubes has been successfully carried out, e.g. at Taynish NNR.

MANAGEMENT THAT WILL HAVE LOW IMPACT IF GUIDELINES FOLLOWED

Selective stem cutting: A more ecologically sensitive and sympathetic way of harvesting stems from Atlantic hazel; selective cutting enables the internal integrity of individual stools to be maintained (and their associated biodiversity), and the cohesion of the stand as an ecological unit.

Short periods of intensive grazing: Atlantic hazel has a natural ability to respond to over-grazing for short periods, but extended continuous heavy grazing reduces viability of the stool and the stand.

Short periods of no grazing: A respite period from grazing results in a general thickening-up of the stand, and can be useful to allow recovery from periods when over-grazing may have reduced viability within the stand; however, subsequent reintroduction of grazing at low to moderate levels is recommended to keep glades open.