A considerable part of the Atlantic coastal dunes is covered with woodland (34.7% in 1993), but only a small part of this (3.7%) is to be considered natural (see: Natural dune woodland). In the past extensive afforestation has been used to stabilise dunes throughout Europe. As a consequence this is supposed to be the main cause of coastal dune habitat decline along the Atlantic shores (see: Woodland management, Reduction of exotic plantation). Nowadays these afforestations seem to have three major functions: (i) recreation; (ii) wood production and (iii) sand stabilization. The planting of artificial forest composed of non-native species can additionally change the hydrological systems, with serious consequences for the ecosystems of wet valleys and lakes and for the seepage volumes into related habitats (1, 2).
 

 1 – Natural dune woodland

Seen from the naturalist point of view ‘coastal woodland’ means any spontaneously grown woody vegetation (trees and shrubs) which is indirectly, but strongly influenced by the sea. Coastal woodlands can physiognomically be characterised in two ways:

(1)  The external structure. Seen from the outside of the formation, the effect of wind and sea drift create a so-called ‘windmorphose’, which means a progressive degradation of the wood volumes to the point that it flattens down to the coastal grassland level.
(2)  The internal structure. Seen from the inside, characteristics depend essentially on the general bioclimate. Refering to this, three main types with transitional stages can be distinguished in Europe: the Tayga type, the Moderate type and the Mediterranean type.

 All remaining natural coastal dune woodlands are suggested to be protected. Only a small part of all the dune woodlands is considered to be natural and this part contains a considerable variety of natural woodlands types. In general only very small fragments are left (2).
 

 2 - Woodland management

In addition to the remaining natural woodlands, considerable parts of the coastal dunes are covered with semi-natural woodlands. Existing semi-natural woodlands could form a basis for the restoration of natural woodland because they often contain a species composition very similar to natural woodlands. It is even practised to manage coniferous forests with more subtle management techniques with positive results (see: Coniferous forest management in the Amsterdam Water Supply Dunes, The Netherlands). Furthermore, EU-subsidies for planting native trees on agricultural land have been increased (2).

 3 - Reduction of exotic plantations

Plantations of exotic/alien species, especially conifers, have been subject to much critisism (see: invasive species control). The evergreen canopy of the pine monocultures traps precipitation and reduces groundwater recharges as well as the conifers should enhance the problem of desiccation caused by excessive evaporation. The needles of the trees are highly acidic and accelerate the natural decalcification process in the calcium-rich dunes. And at least, densely planted forests impede the development of indigenous vegetation because of the darkness under the canopy. Therefore the removal of these plantations will make dune systems more natural. In the Netherlands, a new approach towards conifers has been adapted. The calcium rich and moist conditions of many dune areas in The Netherlands are highly valued in Dutch nature conservation. The acidifying impact and desiccation of conifer plantations is therefore highly undesirable. The new approach conserves old conifer trees (older than 60 yrs), they have significant ecological value. Many of the younger forests will be transformed towards vegetations containing more indigenous dune species (3). In the Anholt Desert, Denmark, several methods to remove pine forest were compared in a restoration programme.

References:

1. Doody (2000; in press): Coastal conservation and management. An ecological perspective.
2. Tekke, R. & A. Salman (1993): Coastal dune woodlands along the Atlantic & North Sea shores. EUCC. Leiden. (BNF93).
3. Swart, B. (1998): Coniferous forest management in The Amsterdam Water Company Dunes. Coastline 98/4: 4-6.