Original scientific paper
SURFACE RAINFALL FLOWOFF AND SOIL EROSION IN FOREST ECOSYSTEMS OF ALEPPO PINE
Vlado Topić
; Institut za jadranske kulture i melioraciju krša, Split
Lukrecija Butorac
; Institut za jadranske kulture i melioraciju krša, Split
Goran Jelić
; Institut za jadranske kulture i melioraciju krša, Split
Abstract
Forest vegetation provides the best protection of soil against accelerated, excessive erosion.
In a well preserved and properly managed forest there is no excessive erosion, only
normal erosion in which the rate of soil erosion is far below the erosion tolerance. However,
a severe degradation of forest ecosystems in the Mediterranean karst area of Croatia considerably
diminishes their anti-erosion function. Nearly 60 % of the area is covered with coppice
forests, scrub, maquis and bare ground, while high forests account for only 3.7 %. Such
an unfavourable structure of the forest fund aggravates erosion processes in this area.
Of the entire Mediterranean karst areas in the Republic of Croatia covering 15,383
km2, about 95 % are affected by varying intensities of water-induced soil erosion, of which
40 % refer to severe erosion. Accordingly, the area is at a high risk of erosion while some of
the regions are already completely degraded. In this highly vulnerable area with respect to
erosion, soil degradation and vegetation devastation, as many as 668 torrents have been recorded
with a total watershed amounting to 3,024 km 2 , which makes it one of the largest
torrent areas in Croatia. The annual soil loss, or sediment quantites irrevocably lost to the
Adriatic Sea, is estimated at 1,140 hectares with soil layers of 20 cm. Soil, an indispensable
natural resource that is painstakingly produced over long periods, makes the issue of its protection
the primary concern. With this in mind, the Adriatic Culture and Karst Amelioration
Institute in Split started scientific research on karst soil erosion and protection in 1964. In
1971, the first experimental plots with measuring instruments were established in torrent
watersheds of the Mediterranean karst. The goal was to obtain original data on essential
characteristics of water-induced soil erosion using up-to-date stationary methods. The plots
are at different inclinations with varied geological and pedological characteristics and they
support a diverse plant cover.
The paper shows the research results of the influence of forest ecosystems of Aleppo
pine (Pinus halepensis Mill.) on surface flowoff of rainfall and protection of soil from erosion.
The research was done in the mouth of the torrent Rupotine near Solin, Ku~ine, on experimental
plots B8 and B9, in preserved and burned stands of Aleppo pine, inclination 20°
and 26° in the period from August 2002 to August 2004.
In preserved stands of Aleppo pine of complete stand, on inclination 26° (plot B8) in the
first year of research, from August 2002 to August 2003, surface flowoff amounted to 6,23
mm/m2, soil loss 0,043 t/ha. On burned area, inclination 20° (plot B9) in that period the
yearly value of flowoff amounted to 35,51 mm/m2 , soil loss 19,93 t/ha.
In the second year of investigation, from August 2003 to August 2004. yearly value of
surface flowoff on the plot under Aleppo pine stand amounted to 4,25 mm/m2, soil loss
0,00022 t/ha. On the burned area, with renewed forest vegetation, in the third year after
the fire, yearly value of surface flowoff amounted to 8,4 mm/m2, soil loss 0,080 t/ha.
Keywords
karst; erosion; experimental plots; Aleppo pine stands; burned area; rainfall; surface flowoff; soil loss
Hrčak ID:
26018
URI
Publication date:
24.9.2006.
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