Å UMARSKI LIST 7-8/1966

A FOREST-PRODUCTIVE ASSESSMENT OF SOILS IN THE REGION OF OGULIN
Summary
Investigated was a 15-year-old culture of Scots Pine (Pinus sylvestris L.),
Austrian Pine (Pinus nigra var. austriaca) and Eastern White Pine (Pinus strcbus L.)
situated within the area of the Croatian Carst, 15 km. south-east of Ogulin. The
culture lies on medium gentle to moderately steep south-facing slopes of a hilly
ground. The parent rock consist cf Middle Jurassic strata of calcareous dolomite. It
is characteristic of the local climatic conditions that the amount cf ramfall is 1500
m. m. yearly, of which 650 m. m. in the growing season. The mean annual temperature
of the air is 10,3° C and in the growing season 16,5" C.
The primary task of the investigation was to establish the productive capacity
with respect to Scots Pine of a leached relict terra rossa and a weakly illimerized
brown soil on calcareous dolomite by the help of the produced volume in the investigated
culture.
In the course of the investigation the authors came to the following conclusions:
1. Comparing the volumes produced on the described localities it was established
that the increment of the standing crop depends considerably on the tree
species and soil type.
2. On a leached relict terra rossa as compared with the weakly illimerized soil
Scots Pine achieves at 15 years of age — under other conditions being equal
— a considerably higher volume. On the basis of the diferences in the volume
increments of Scots Pine the index of the natural productive capacity was
established, which for the leached relict terra rossa in relation to the illimerized
soil amounts to 272.
3. In the same locality, i. e. on a leached relict terra rossa Scots Pine achieves
at the age of 15 years an about 2,5 times higher volume than Austrian Pine.
4. Under equal environmental conditions Eastern White Pine and Scots Pine
display up to their age of 15 years the same growth rate.
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