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ŠUMARSKI LIST 13/2005 str. 31     <-- 31 -->        PDF

S. Matić, 1. Anić, M. Oršanić: SILV1CULTURAL TREATMENTS AIMED AT IMPROVING THE ANTI-EROSION ... Šumarski list SUPLEMRNT (2005), 17-30
FORESTS OF THE MI HTERRANEAN AREA


In no other Croatian area is the issue of anti-erosion
and water protection forest function as important as in
the Mediterranean region. The forests in this area have
for centuries been exposed to intensive anthropogenic
influences. These influences commonly involve bad
forest use, including, for example, irrational and uncontrolled
felling for the purpose of obtaining raw timber
material for a variety of needs, browsing and grazing,
the removal of duff and leaf litter, slashing branches
and pollarding, burning and clearing forests for
agricultural areas, converting forests and forestland to
meet the needs of infrastructure, tourism, viniculture,
olive-growing and similar. In combination with fires,
the specific climatic conditions and the erosive soils,
these long-lasting influences have gradually led to the
general degradation of Mediterranean forest ecosystems.
The morphology and the silvicultural and structural
characteristics of forest stands have been disturbed,
and so have the vitality, stability, productivity, the
ability of natural regeneration and the capacity of fulfilling
all the functions expected from a Mediterranean
forest ecosystem.


The Croatian forest experts investigated and described
different degradation forms of Mediterranean forests
many years ago (Petračić 1942, 1938, Anić
1966, 1963, 1942, 1942a, Marčić 1955). The sequence
of the Mediterranean forest ecosystems in the process
of regression and progression, as well as their dynamics
were also established (Anić 1959, Rauš 1987, Matić
et al. 1997). Even more importantly, the answers to
the question concerning the treatment of each degradation
form aimed at changing their development into a
progressive direction were provided by Matić et al.
1997, 1996, Matić and Rauš 1986.


Mediterranean forests pose a permanent challenge to
forestry, especially in terms of afforesting wasteland,
garrigues, pseudogarrigues and scrub, tending and regenerating
newly-established and the existing forest
stands and actively protecting the degraded forest forms
such as maquis, pseudomaquis and scrub. These are the
most important silcivultural treatments which should be
renewed in order to improve the anti-erosive and water-
protective functions of the forests in this area. One of
the crucial preparatory activities to be performed before
the application of the above treatments is to draw up a
management plan. A management plan is the first and
the basic step in the management of Mediterranean forests
and especially in the management of degraded
forms of holm oak and pubescent oak forests (maquis,
pseudomaquis, garrigues, pseudogarrigues, scrub, thickets,
and mild and severe wasteland).


Afforestation is a permanent activity; only by increasing
the areas under forests is it possible to increase
the non-commercial and commercial value of Mediter


ranean forests. Preparatory activities have particular
importance with regard to the fact that the area to be afforested
in the Mediterranean karst in Croatia covers
almost 400,000 ha (Matić andPrpić 1983). In order
to perform these activities satisfactorily, it is necessary
to plan the whole procedure carefully, select priority
areas to be afforested, choose the time and the tree species
for afforestation, prepare the soil, plan working
techniques and control the quality of performance.
Among others, priority in afforestation should be given
to those forest areas in which the newly-established
stands will have a distinctive anti-erosive and water-
protective role. One of the best examples in Croatia is
the project of afforesting and improving the torrential
area of Senjska Draga (Ivančević 2003).


In order to fulfil their commercial and non-commercial
functions, the stands derived from afforestation
or regeneration of old stands should not be allowed
to develop spontaneously; on the contrary, they
should be tended since their earliest youth. For example,
some possible tending activities in young forest
cultures may include ridging, fertilizing and mulching
the soil around the young plants. In addition, protection
measures against adverse abiotic (wind, fires, sun
scorch and sea spray) and biotic (goats, sheep, fungi
and pests) factors should be applied, as well as restocking,
cleaning and thinning.


Regeneration of Mediterranean forests usually comprises
the following cases:


1.
regenerating stands with climatogenic tree species
2.
regenerating stands with pioneer tree species and simultaneous
complete or partial replacement of a
pioneer with a climatogenic tree species (complete
or partial substitution of the stand form)
3.
regenerating stands with pioneer tree species without
substitution
4.
indirect conversion of degraded forms
5.
direct conversion of silvicultural forms.
The first case is also the rarest. The holm oak forest
of Kalifront (including the area of Dundo) on the island
of Rab, covering approximately 1,000 ha, is probably
the largest preserved complex of this size in the whole
Mediterranean region. It is very rare to come across
examples of regeneration of old holm oak stands. Past
research in Croatia has shown that, with regard to susceptibility
of holm oak seedlings to sudden changes in
the light conditions and moisture in the regeneration
area, regeneration should be accomplished with the
shelterwood method and with gradual dosages of light
in accordance with the needs of the seedlings and the
young growth (M at i ć and Rauš 1986, Prpić 1986,
Krejči andDubravac 2004).