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ŠUMARSKI LIST 7-8/2011 str. 31     <-- 31 -->        PDF

D. Kajba, J. Domac, V. Šegon: ESTIMATION OF SHORT ROTATION CROPS POTENTIAL IN THE REPUBLIC ... Šumarski list br. 7–8, CXXXV (2011), 361-370


cludes a total of 65 soil types based on current utilisation
and soil characteristics.


After taking into account the current land utilisation
and eliminating the land which is already used for agricultural
purposes as well as forested land, the following
results regarding the maximum land availability in
Croatia are obtained:


Estimation of potential


Theoretical potential –
Based on pedological study of agricultural areas,
specialized pedological maps of the Republic of Croatia
and a hydropedological map were constructed
which designate potential areas for the cultivation of
agricultures.The Croatian agricultural sector also offers
potential possibilities for renewable energy production
through biofuel production in uncultivated
areas.Apart of the areas with temporarily unsuitable
soils (611 324 ha) and areas with permanently unsuitable
soils (806 648 ha) could be used for the establishment
of short rotation cultures of forest tree species in
the period of 15 years at most.
Taking into account the various soil characteristics
which define limiting factors for energy crops production,
the available area is further reduced.This area is
then used in order to obtain the theoretical potential for
energy crops cultivation in Croatia.
The main results can be summarized as follows:


Forest area suitable for energy crops – out of the
maximum of 180 000 ha (uncovered forest land), a
total of 51 200 ha was estimated to be suitable for
SRC


Agricultural areas with moderately suitable soils
and limited soil suitability – out of the maximum of
900 000 ha a total of 617 100 ha was estimated to be
suitable for SRC.


Technical potential –


Forest area suitable for energy crops – maximum of
approximately 180 000 ha (unstocked forest land,
suitable for forests, seeTable 3)


Agricultural areas with moderately suitable soils
and limited soil suitability – maximum of approximately
900 000 ha (seeTable 2, area with moderately
suitable soil and area with limited soil
suitability)


– Procjena potencijala
Teoretski potencijal
Of the total forest area suitable for energy crops,
about 31 000 ha are heavy hydromorphous clay type of
soils and 20,200 ha are slightly better clay type of soil.


Therefore, the production of about 8 t DM per ha*y
on average can be expected in the area of 31 000 ha,


-1


with this average rising to 11t DM per ha*y in better
sites.Although some tested clones show the production


-1


higher than 20 t DM per ha*y , it is more realistic to
expect the average production mentioned(Kajba et
al. 1998, 1999a, 1999b, 2004, 2007a, 2007b, Kajba
2009).This estimate does not envisage the use of any
intensive agrotechnical measures (additional nutrition
during the first two-year rotation cycles, pest control,
and others).


On average, based on the testing and research conducted
in Croatia described within the previous chapters,
with six rotations (six cutting operations executed two
years apart) a maximum average production of 12 t DM
per ha/y can be expected on the agricultural area with
moderately suitable soils and limited soil suitability.


Taking into account the limitations and mentioned
values, the total yield corresponding to the theoretical
potential amounts to 7 874 200 t DM/y.Applying the
standard energy content for willow wood of 18.4
MJ/kg DM (FAO 2004) this translates into 144.9 PJ/y.


Tehnički potencijal
The estimation of the technical potential is based on areas within parts of Dalmacija, Istra, Gorski kotar
the theoretical potential presented in the previous chap-and Lika (partly mountain areas with too steep incliter,
while taking in consideration the status and limita-nation for effective harvesting).
tions of technology for harvesting energy crops which


Even though Croatia is not yet a member of the Eucan
be applied in Croatia. These considerations are


ropean Union, its Nature protection act has already immainly
derived from the type of soil and terrain as in


plemented many mechanisms that transpose the EU
certain cases the terrain configuration and soil type


Habitats Directive provisions in regards to naturally
practically limit and or prohibit the use of harvesting


pretected areas. Specifically, Croatia will have to pro-
machinery. Specifically, the following areas were iden


pose sites for the Natura 2000 Network for over 250
tified as unsuitable for harvesting short rotation crops


species and 70 habitat types that occur in Croatia. Up to
in Croatia:


now around 1000 possible sites have been identified


areas within or in the vicinity of alluvial deposits which have been put out to public consultation.
near the main Croatian rivers and their confluents;
After taking into account the location and area of



areas within parts of Posavina, Podravina and Poku-the Natura 2000 sites, as well as the areas unsuitable
plje (swampy areas near rivers Sava, Drava and Kupa); for harvesting, and deducing it from the numbers pre