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ŠUMARSKI LIST 9-10/2008 str. 31     <-- 31 -->        PDF

N. Pernar, D. Bakšić, V. Bobić, I. Perković: STANJE TLA U MIKRODEPRESIJAMA ŠUME ŽUTICA Šumarski list br. 9–10, CXXXII (2008), 405-417
phenomena, resulting from the disturbed ecological balance, are associated
with intensive commercial activities in the area during the period mentioned

The basic hypothesis is that the ecosystem has undergone complex disturbance,
which is associated with the following: oil well fluid spills in the past
40 years, hydrological changes resulting from a dense road network built to
serve the needs of the oil-gas field and forest management. To a lesser extent,
it is also linked with hydrological and microbiological changes associated
with occasional retention of floodwater.

The purpose of our research was to identify some possible causes of these
occurrences from the aspect of chemical and biological soil condition. We
focused on the analysis and monitoring of chemical and biological properties
of the surface soil in the lowest localities (microdepressions). Phosphorus
and potassium concentrations and trace elements were investigated, and so
were mineral oils and total lipoidal substances, as well as microbiological
activity. The research is based on twice-yearly measurements of the above
parameters in 14 points in those microdepressions whose location (e.g. in
relation to some possible contamination with oil well fluids), as well as the
occurrence of pedunculate oak dieback has led us to conclude that they represent
micro-sites most exposed to the mentioned impacts.

Although the forest of Žutica is a homogeneous area in geographic and
relief terms, the surface part of the soil in this forest has proved to be physiographically
highly heterogeneous. With regard to oil carbohydrates, the soil
is not contaminated over larger areas. Therefore, contamination as such is
not considered responsible for tree dieback over larger areas.

Permanent sources of pollution at the level of very weak contamination
are associated with restored mud ditch, but they are probably not reflected on
the wider Žutica area. Microbiological parameters indicate populations of
adapted micro-organisms which ar The concentration of trace elements in the
soil is within geogenic values, whereas some occasional anomalies occur in
the locations which have been recovered after oil well fluid spills.

K e y w o rd s : forest soil, contamination soil, forest Žutica.