prilagođeno pretraživanje po punom tekstu

ŠUMARSKI LIST 13/2005 str. 32     <-- 32 -->        PDF

S. Malić. I. Aiiic, M. Oršanic: SILVICULTURAL TREATMENTS AIMliD AT IMPROVING THE ANTI-EROSION ... Šumarski list - SUPLEMF.NT {2005), 17-30
The second case involves regeneration of a transitional
forest, when the elements of a climatogenic forest
community are successfully regenerated under the
canopy of the pioneer pine stand. In this case, regeneration
must be performed using the methods under the
crown cover of the old trees, usually with shelterwood
cuts in small areas (Anić 2003). The small areas may
be in the form of circles, or less frequently in the form
of strips. Their density, area and form should be listed
in a carefully executed silvicultural plan, which should
also contain a cartographic scheme of the initial regeneration
areas, logging directions and methods of area
enlargement, in dependence of the tree species being
regenerated and the geomorphology of the whole regeneration
area. Regeneration begins in the initial regeneration
area, which is gradually expanded and joined
with another using one of the cutting methods: shelter-
wood cutting or marginal cutting. When young natural
generation is insufficiently dense, regeneration may be
a combination of natural and artificial regeneration.
Artificial regeneration requires the use of seedlings
and seeds in the quantities prescribed for a given tree
species (Matić 1949).

The third case relates to regenerating a stand with
pioneer tree species, which is usually Aleppo pine or
black pine. On steep, erodible slopes, regeneration is
accomplished in small circular areas. The canopy can
be severely broken since these arc pioneer, heliophilic
tree species. On mildly sloping terrains the size of initial
regeneration areas may be larger.

Indirect conversion of degraded forms is actually a
natural process of their progressive development. This
process is enhanced and supported with active protection,
which will be discussed later.

Direct conversion of a silvicultural form usually denotes
the conversion of a forest stand of a low silvicultural
form into a stand of a high silvicultural form by
regeneration. It is performed with the shelterwood method
and commonly involves the combination of natural
and artificial regeneration. This procedure is applied
in many old pubescent oak coppices in Croatia
(Matić etal. 1996).

Active protection comprises procedures aimed at
protecting forests and degraded forest forms in the Mediterranean
area from those factors which have been
the agents of degradation processes. These procedures
are primarily preventive measures against fires, illegal
and uncontrolled felling, browsing and grazing. In higher
degradation forms (a transitional form between
maquis towards a low forest and in a thicket-like low
forest), it is possible to apply tending treatments with
cleaning, which accelerates and regulates the process
of direct conversion of a degraded form. This is particularly
important in the sites in which the forest stands
are intended to perform anti-erosive and water-protective

All the above silvicultural operations should be
planned and carefully performed to achieve the highest
quality. The quality of silvicultural procedures must be
the only control measure (Matić 1989). The speed of
execution or the number of the procedures without regard
for quality may save money in the short run, but
will lead to forest degradation and increased cost of forest
improvement in the long run. Damage that may be
incurred usually has long-term consequences.


The two principal groups of silvicultural treatments
are tending and regeneration. The goal of forest tending
is to regulate and sustain an optimally structured
forest stand in natural and undisturbed site conditions.
These conditions must be maintained in all stages of a
stand´s development. Tending affects both the stand
structure and the site. A well-tended forest ecosystem
is capable of optimal fulfilment of its commercial and
non-commercial functions (ecological and social). The
anti-erosion and water-protective functions are among
the most important ecological functions that a well-
tended forest ecosystem provides.

The vital task of regenerating a forest is to preserve
the forest soil from adverse impacts which may cause
degradation processes. The forest soil is protected with
a permanent cover of the stand´ crown canopy. This is
why forests should be regenerated under the crown cover
using the shelterwood system or the selection sys

tern. Regeneration over small areas should be recommended.

Since its beginning, the Croatian forestry has advocated
the natural approach to forests. This approach
involves natural forest regeneration with the shelter-
wood method and the maintenance of the optimal
structure of the forest stand with tending. This has resulted
in exceptionally natural forests capable of fulfilling
their commercial and non-commercial functions.
Their naturalness is one of the prime reasons for which
the Croatian forestry has earned recognition for ecological
production of mercantile timber from all its forests.
Even more importantly, Croatia is one of the richest
European countries in potable water. Forests
grown and tended according to the principles of the Zagreb
School of Silviculture are one of the main reasons
for such a favourable condition.