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ŠUMARSKI LIST 13/2005 str. 217     <-- 217 -->        PDF

1. Tikvić. D. Puntane. 2. Zečić. D. Ugarković, Z. Seletković: TI Ili IMPACT OH MONTANE FOREST Šumarski list SUPLEMENT (2005), 202-218
of forest ecosystems. Indicators of water quality in pro- compared in order to determine the effects of forest
tected areas and in commercial forests were finally management on water quality.


RESULTS
PHYSICAL-CHEMICAL INDICATORS OF WATER QUALITY IN WATERCOURSES


Table 2 shows indicators of physical-chemical features
of water from the watercourses in the area of Papuk,
Plitvice Lakes and Velebit. With regard to pH values,
water samples in all the localities belong to the
first category (I), except in the locality of Papuk 1,
where water bordered between the first and the second
category (I and II) (Fig. 1). On average, the lowest pH
values were found in the area of Papuk and the highest
in the area of Plitvice Lakes. By localities, the highest
differences in pH values of water were found in the watercourses
of Papuk, and the smallest in the area of Plitvice
Lakes (Tabic 2). Values of pH in the watercourses
outside the forest ecosystems did not differ significan


tly from those in the forests. No differences were found
in the pH value of water between protected areas and
commercial forests.


Electrical conductivity values were the highest in
the area of Plitvice Lakes. The majority of the watercourses
were in the first (I) water category, except for
the localities Plitvice 3 and 4, which were in the second


(II) category. The localities Papuk 1 and 2 had significantly
lower values of electrical conductivity than other
localities. Higher electrical conductivity values
were found in the protected area in relation to commercial
forests, while no differences were found between
the localities in and outside the forest.
OXYGEN REGIME IN WATERCOUSES


No differences were found between the localities in
terms of dissolved oxygen values, oxygen saturation
and chemical requirements of oxygen, except for the
locality Papuk 2, which showed considerable aberration
from these indicators in relation to other localities.


In terms of dissolved oxygen, all watercourses contained
the first-category water (I), except for the sample
from the river Orljava (Papuk 2). Oxygen saturation
in the area of Papuk was slightly lower and in Plit


vice Lakes slightly higher, so three samples had water
quality of the second category (II) (Fig. 2). Chemical
oxygen consumption (COC) was similar in all the watercourses,
except for the sample from the river Orljava,
where COC values were 30 times higher than those
in other Papuk localities (Table 2). Higher COC values
indicate an increased content of hardly soluble organic
matter in water. No oxygen regime indicators were measured
in the area of Velebit.


NUTRITIVE AND ORGANIC MATTER AND MICROBIOLOGICAL
INDICATORS OF WATER QUALITY IN WATERCOURSES


Nitrates are the only nutrients found in water samples
from the watercourses. In terms of nitrate content,
the majority of the watercourses belonged to the second
category (II), except for the locality Velebit 1 and
3, whose waters were in the first category (I) (Table 3).
No differences were found between the protected area
and commercial forests, nor were they found between
watercourses in and out of forests.


The average proportion of aerobic bacteria was the
lowest in Plitvice Lakes, slightly higher on Papuk and
the highest on Velebit. All aerobic bacteria values were
within the first-category water, except the river Orljava
(Papuk 2), where the quantity of aerobic bacteria exceeded
that in other watercourses by up to 250 times. No
differences were found between the protected area and


commercial forests, whereas a significantly higher
quantity of aerobic bacteria was found in the watercourses
outside the forests compared to those in the forests.
The mineral oil content in the majority of the
samples was within the limits of the first-category water.
Only the samples from the Orljava (Papuk 2) and
the stream Veliki Tisovac (Velebit 4) had water of the
second category. Higher values of total oil quantities
were found in the watercourses outside the forests in
relation to those in the forests. Minimal values were
found in the watercourses on Velebit and on Papuk
(Fig. 4). No differences in the quantity of mineral oils
and total oils were established between protected areas
and commercial forests.


DANGEROUS SUBSTANCES AND METALS IN THE WATERCOURSES OF MONTANE CROATIA


In terms of cyanide content, water in the majority of
the watercourses belonged to the second category (II).
The least cyanide was registered in Plitvice Lakes,
while the most was found on Velebit. Velebit also sho


wed the highest differences between particular watercourses
in the same area. In terms of cyanide content,
higher cyanide concentrations were found in commercial
forests compared to those in the protected area,