出版社：Arbeitsgemeinschaft Forstliche Standorts- und Vegetationskunde (AFSV)
摘要：Investigations were performed in the New Red Sandstone region of the `High
Spessart´ in north-west Bavaria (Lower Franconia District), which is famous for
extensive beech (Fagus sylvatica) forests on historical woodland sites
with continuous tradition of broadleaved tree-cover. Under cool-humid and
mild-winter upland conditions (`submontane/oceanic´) the beech achieves its
maximum competitive power and tends to form pure stands of acidic beech forest
(L u z u l o - F a g e t u m, upland-form). The main goal was to evaluate the
effects of the `Rothenbuch concept´, only 15 years after its implementation, on
the diversity of structures and biodiversity. For this purpose mature stands of
Beech (located in Rothenbuch) managed according to the guidelines of the concept
were compared with conventionally managed stands (located in Altenbuch). Targets
of the concept are protection of trees occupied by eyries of tree-breeding
birds, retention of at least 10 ecologically valuable trees per hectare,
conservation and accumulation of an average 10 m³ dead wood of over 20
centimeters dbh per hectare (excluding stumps and canopy dead wood).
Implementation of the concept in forest management follows the principle “before
an old tree is removed, a balance must be made between the estimated yield of
timber, silvicultural necessity and the tree’s ecological value”. In Rothenbuch
and Altenbuch 30 grids of 1ha (bird study; rare forest structures with a
clustered distribution) and 25 circular plots of 0.1ha (other groups and more
frequent structures) were installed. Birds were surveyed at the time of
incubation by quantitative grid mapping. Saproxylic beetles were sampled by
flight-interception traps and time-based manual capture. Snails and
wood-inhabiting fungi were surveyed by standardized collections on 15 of the 25
circular sample plots. Three null hypotheses were tested: (i) Rothenbuch concept
has as yet had no effect on quality and quantity of lying and standing deadwood
structures and habitat trees (ii) Rothenbuch concept has as yet had no effects
on abundances and species richness of floral and faunal species indicator groups
(iii) Rothenbuch concept has as yet had no effects on abundances and species
richness of endangered species dependent on temporal continuity of tradition in
habitats and structures The follow up study revealed no significant differences
between the two sites in terms of the quantity of habitat trees (i.e. living
trees with mulm- and rot-holes, rotten crown sections and dead knots, crevices
etc.). However, we recorded increased deadwood resources at the Rothenbuch site:
lying stems, standing snags and larger diameters. Consequently, more bird
species and individuals were present there. We found a particularly pronounced
difference in hole-nesters, whereas for birds linked to particular wood
structures only a trend was observed. According to a species indicator analysis
the following sensitive bird species were found to be significantly more
frequent and constantly present at Rothenbuch: middle-spotted woodpecker, great
tit, redbreast, grey woodpecker, pied and collared flycatcher, marsh tit and
blackcap. On the other hand only common chaffinch proved to be a faithful
species in Altenbuch. Species numbers and abundances of terrestrial molluscs and
saproxylic beetles were also significantly increased at Rothenbuch, including
endangered species listed in red-data books. Moreover, higher numbers of species
and abundance of wood-inhabiting fungi were recorded. The results correlated
with the increased deadwood resources in Rothenbuch. However, the unchanged low
numbers of habitat trees and the lack of important indicator species prove that
the period of 15 years was not sufficient for the appearance of habitat trees
with suitable microstructures. The frequency of deadwood is furthermore still
inadequate for a broader re-colonization by the scattered relict species of
virgin forest which are considered to be closely associated with primeval
structures and features. In the meantime the concept of the Bavarian state
forestry organisation (NEFT 2006) has gone one step further in setting a target
dead wood volume of at least 40 m³ per hectare for beech stands older than 140
years, and complete removal of stands older than 180 years from utilization.
