DIGITALNA ARHIVA ŠUMARSKOG LISTA
prilagođeno pretraživanje po punom tekstu



ŠUMARSKI LIST 13/2005 str. 49     <-- 49 -->        PDF

PRESENTATION AT THE INTERNATIONAL SYMPOSIUM Šumarski list - SUPLEMENT (2005), 40-50


THE IMPACT OF SCRUB VEGETATION OF ORIENTAL HORNBEAM
(Carpinus orientalis Mill.) ON SOIL PROTECTION
AGAINST EROSION IN CROATIA


Vlado TOPIC, Lukrecija BUTORAC*


SUMMARY: The paper presents research results of the effects of oriental
hornbeam (Carpinus orientalis Mill.) scrub vegetation on soil protection
against rain-induced erosion. Oriental hornbeam scrub covers the largest
area in the sub-Mediterranean karst region in Croatia. Research was conducted
in the period from 1999 to 2003 and encompassed sample plots B6 and B7
on the slopes of Mount Moseć near Muć. The plots have an inclination of 26°
and are built of chalky limestones overlaid by shallow brown soil (calcocambisol).
The vegetation cover on the plots ranges from 61.14 % (Plot Bi)
to 65.34 % (Plot B6). The mean height of oriental hornbeam is 1.59 m and


1.79 m respectively. Since the plots have equal geological, pedological and
vegetational characteristics and receive equal amounts and intensities of precipitation,
the scrub in sample plot B() was cut down for more detailed erosion
research in 2001. Before the scrub was cleared, the values of surface runoff
were slightly higher in Plot B?, which had a little less cover.
After the scrub in Plot B6 was cut down, but the leaf litter and the humus-
accumulative horizon were preserved, the mean annual value of surface runoff
was 24.03 mm/m2 (240.3 m3/ha), the runoff coefficient was 0.019 and soil
loss amounted to 0.00672 t/ha. In sample plot B7 with preserved oriental
hornbeam scrub, surface runoff was 19.53 mm/m2 (195.3 m3/ha), the runoff
coefficient was 0.0156 and soil loss was 0.0056 t/ha.


Key words: karst, erosion, sample plots B6 and B7, oriental hornbeam
scrub, precipitation, surface runoff, soil losses


INTRODUCTION


Forest vegetation is the most efficient factor in soil


About 95 % of the 15.383 km2 of Mediterranean


protection against accelerated, excessive erosion. A


karst in the Republic of Croatia is affected by varying


well preserved and properly managed forest is not sub


intensities of water-induced soil erosion, of which se


ject to accelerated erosion but only normal erosion in


vere erosion accounts for 40 %. Consequently, the


which soil erosion rate falls far below the erosion tole


whole area is critically threatened by erosion, while


rance level. However, the anti-erosion function of the


some parts are already completely degraded. The


forest ecosystems in the Mediterranean karst area is di


ecologically highly sensitive area in terms of erosion


minished due to their severe degradation. Nearly 60 %


risk, soil degradation and vegetation devastation con


of the area is covered with coppices, scrub vegetation,


tains 668 torrents with a total watershed area reaching


maquis and bare ground, while high forests account for


3,024 km . This makes it one of the largest torrential


only 3.7 % (Topic, 1994). Such an unfavourable


areas in Croatia (Topic and Leko 1987, M i četić


structure of the forest fund definitely enhances erosion


2000, Topic 2003). The annual soil losses, or the


processes in the area.


quantities of sediments irrevocably lost to the Adriatic
Sea, are estimated at 1,140 hectares of a 20-cm deep


* Vlado Topic, PhD, Lukrecija Butorac, BSc, soil layer. Karst soil is an indispensable natural resourInstitute
of Adriatic Cultures and Karst Amelioration,


ce, but since its production is time-consuming and dif-


PutDuilova 11,21000 Split