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ŠUMARSKI LIST 13/2005 str. 70     <-- 70 -->        PDF

K. Gubka: THE STRUCTURE OF THE FOREST STAND WITH A SOIL CONSERVATION FUNCTION Šumarski list SUPLEMENT (2005), 61-68
changing from a vertically differentiated stand structure
to a horizontally leveled forest stand. This is manifested
by a marked decrease of the counts of individuals
in the lowest (fourth) tree class where during a ten-
year period about 100 individuals aborted. On the other
hand, the share of codominant trees (second tree class)
considerably increased. Natural regeneration of tree
species at the investigated locality is very good. The
seed crop of sycamore (Acer pseudoplatanus) and Norway
maple (Acer platanoides) is usually spontaneous,
but due to a strong shading, survival rates of maples are
very low. Applying a targeted selection of individual
trees and small groups, it is possible to achieve a vertically
and horizontally differentiated tree community
with a maximum functional efficiency. During the period
1994 - 2004, the representation of individual tree
species changed negligibly.


The change of the stand structure with altitude results
in a change of ground vegetation. According to
N i č (2004), these stands represent a typical example
of hollow and scree communities with predominance
of nitrophilous species. The cover of the plant synusia
is relatively low (30 %) because of the influence of the
terrain shape and a stony surface. According to Prof.
Zlatnik, the community belongs to the nitrophilous
edaphic-trophic order C. In spite of a rich representation
of noble hardwoods of average quality, majority of
these communities are protection forests, considering a
high share of gravel and stones in the soil itself and on
the soil surface.


From the point of view of soil, altitudinal change
was reflected in soil characteristics, mainly in the
depth, colour and chemical composition of soil. Rich
rooting mainly in the upper soil layers is one of the prerequisites
of the stability of the ecosystem concerning
soil erosion.


The soil state is shown in the analysis of the soil
probe.


The inspection of the forest revealed that the static
stability of the forest stand is reduced, so that the function
of the forest stand is endangered.


There are several reasons:


In the upper part of the forest stand, where oak is


predominating due to a vegetation inversion, there


are places where several trees died because of fun


gal disease. These groups are gradually breaking up


and canopy is opening. Formation of larger groups


with significantly reduced stocking decrease the re


sistance of the surrounding forest stand against


abiotic factors mainly winter, snow and hoar frost.


There were windbreaks of beech in the hollows,


mainly beneath the view point. These windthrows


may be caused by several factors:


Long-lasting rains and gusty winds. Long-lasting
rains destabilize the soil, roots are weaklym anchored
and an accidental strong wind can throw such
trees, whereby a chain reaction can appear.


Heavy snowfall on soil which is not frozen followed
by gusty winds.
These localities become later starting point for soil
erosion or soil slide.
Terminal breaks which decrease canopy closure are
caused by hoar frost and snow combined with wind
According to the Forest management plan, the forest
stand is 165 years old. There are, however, also
much older individuals, reaching physiological senility.
They die away, break up, so that they form larger
or smaller gaps in the canopy. This also can affect
the stability of the upper tree layer.


This state indicates a necessity to form the internal
forest stand structure, avoid leaving the forest stand
without intervention relying on autoregulation.


It is necessary to apply technological practices and
measures which ensure a dynamic development of the
forest stand with a stable structure, whereby its functional
efficiency must be preserved.


We recommend:
To realize thoroughly sanitary cuttings
Not to allow clear cutting, mainly along the
slope line
Not to apply uniform shelterwood system


Applying group shelterwood system of regeneration
to form vertically and horizontally differentiated
tree community (Baden shelterwood cutting,
group shelterwood system)
To accomplish tree felling during the winter, on
snow or on frozen soil to prevent erosion, and to use
cableway systems for skidding
Where skidding is impossible, to leave trunks in the
forest stand oriented along the contour line
The rests after felling should be laid in the contour
line direction


To achieve natural regeneration everywhere
possible
On places where generative regeneration is impos


sible, it is important to achieve vegetative regeneration
(coppice)
Places without sufficient natural regeneration must
be completed by planting or combined regeneration
Young forest stand must be protected against game
damage


Not to perform any earth works on the vulnerable
terrain.