16.4 Which Climate Change Impacts Are Relevant
for Forest Habitats and their Conservation Status
According to the EU Habitat Directive?
16.4.1 Habitat Change Following Disturbance Events
Although the frequency of large-scale disturbances within the BR is similar to other
regions, spruce-dominated forest associations are nevertheless characterised by a
particular vulnerability (Wermelinger 2004; Schu ¨tz et al. 2006). Due to the predominant occurrence on windy ridges and adjacent to treeless bog areas as well as
the frequent formation of pure stands on peats, gleys, other hydric soils and on
blocky or silicate scree material, shallow rooting spruce trees and stands are
especially vulnerable for stand-replacing disturbances.
Although these disturbances may create deadwood and valuable micro-habitats
(e.g., upturned root plates), the loss of intact stand structures will result in an area
loss subject to reporting under the Habitat Directive for the registered forest habitat
type 9410. The re-registration of a damaged stand and the subsequent evaluation of
its conservation status can only be initiated following forest management measures
or the onset of succession. The failure of spruce as dominant species will have a
long-lasting negative effect on the criteria related to habitat-typical species composition. Impairments, particularly of the forest floor and the hydrology, are likely.
Valuable spatial structures such as the fine-grained mosaic of different forest
development phases are often homogenised by large-scale disturbances and thus
depreciated. Moreover, the total loss of medium and large-diameter trees due to
disturbance events results in the worst rating with respect to spatial structures. If,
additionally, snags, biotope and over-mature trees are blown down and more or less
entirely lost, forest habitat types may be at risk of general downgrading in terms of
habitat structure. Large amounts of disturbance-induced downed deadwood, however, may at most result in a ‘good’ rating for the deadwood criterion.
In the BR, the Vaccinio-Piceetea habitats located along the bog edges within the
FFH areas DE 5330-301 ‘Schneekopf-Schmu ¨cker Graben – Großer Beerberg’ and
DE 5331-301 ‘Erbskopf-Marktal und Morast-Gabelta¨ler’ have a particularly high
risk of storm damage due to elevation, slope angle, slope direction and relative
exposition compared to the surrounding areas. Located in the Northwestern and
Eastern parts of the BR, these habitats are mostly left to develop naturally as part of
the core zone (Fig. 16.5).
Small-scale, species- or structure-specific failure of individual elements of forest
ecosystems may have no or even a positive effect on the evaluation of the conservation status of forest habitat types. This applies particularly to spatially intimate
mixtures of different forest development phases and to snags, biotope and overmature trees. The immediate post-disturbance establishment of early successional
phases of tree species typical for the respective habitat may also result in improved
ratings. Potential impairments due to small-scale disturbances will not be serious.
16 Potential Impacts of Climate Change on Forest Habitats in the Biosphere. . .
251
for Forest Habitats and their Conservation Status
According to the EU Habitat Directive?
16.4.1 Habitat Change Following Disturbance Events
Although the frequency of large-scale disturbances within the BR is similar to other
regions, spruce-dominated forest associations are nevertheless characterised by a
particular vulnerability (Wermelinger 2004; Schu ¨tz et al. 2006). Due to the predominant occurrence on windy ridges and adjacent to treeless bog areas as well as
the frequent formation of pure stands on peats, gleys, other hydric soils and on
blocky or silicate scree material, shallow rooting spruce trees and stands are
especially vulnerable for stand-replacing disturbances.
Although these disturbances may create deadwood and valuable micro-habitats
(e.g., upturned root plates), the loss of intact stand structures will result in an area
loss subject to reporting under the Habitat Directive for the registered forest habitat
type 9410. The re-registration of a damaged stand and the subsequent evaluation of
its conservation status can only be initiated following forest management measures
or the onset of succession. The failure of spruce as dominant species will have a
long-lasting negative effect on the criteria related to habitat-typical species composition. Impairments, particularly of the forest floor and the hydrology, are likely.
Valuable spatial structures such as the fine-grained mosaic of different forest
development phases are often homogenised by large-scale disturbances and thus
depreciated. Moreover, the total loss of medium and large-diameter trees due to
disturbance events results in the worst rating with respect to spatial structures. If,
additionally, snags, biotope and over-mature trees are blown down and more or less
entirely lost, forest habitat types may be at risk of general downgrading in terms of
habitat structure. Large amounts of disturbance-induced downed deadwood, however, may at most result in a ‘good’ rating for the deadwood criterion.
In the BR, the Vaccinio-Piceetea habitats located along the bog edges within the
FFH areas DE 5330-301 ‘Schneekopf-Schmu ¨cker Graben – Großer Beerberg’ and
DE 5331-301 ‘Erbskopf-Marktal und Morast-Gabelta¨ler’ have a particularly high
risk of storm damage due to elevation, slope angle, slope direction and relative
exposition compared to the surrounding areas. Located in the Northwestern and
Eastern parts of the BR, these habitats are mostly left to develop naturally as part of
the core zone (Fig. 16.5).
Small-scale, species- or structure-specific failure of individual elements of forest
ecosystems may have no or even a positive effect on the evaluation of the conservation status of forest habitat types. This applies particularly to spatially intimate
mixtures of different forest development phases and to snags, biotope and overmature trees. The immediate post-disturbance establishment of early successional
phases of tree species typical for the respective habitat may also result in improved
ratings. Potential impairments due to small-scale disturbances will not be serious.
16 Potential Impacts of Climate Change on Forest Habitats in the Biosphere. . .
251