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ŠUMARSKI LIST 3-4/2000 str. 23     <-- 23 -->        PDF

J. Šalek-Grginčić: UR1-ĐIVANJI- PRIVATNIH ŠUMA HRASTA K1TNJAKA (Qiiciviis pelraea Licbl.) NA PODRUČJU... Šumarski list hr. 3 4, CXXIV (2000), 123-141


silvicultural form should be managed exclusively according to the principles used
for even-aged stands.


3. In privately owned stands, in which regular and expert management is most commonly
absent, mean trees often have smaller diameters, and at times smaller
heights than is prescribed in table values for a certain site class. For more reliable
site assessment it is necessary (for certain stand ages) to compare not only
the heights of mean trees (both table and concrete), but also check whether the
heights in height curves of concrete stands are within the boundaries of the quality
(Table 10).


Assessment will not be reliable if concrete stand height curves are compared with
Suric´s site quality height curves (Figure 10). Mean stand heights can be compared,
however, as seen in the mentioned graph.


4. Despite the fact that the stands in question have not been regularly managed, relatively
high values of basic structural elements were obtained in relation to the
compared yield tables.


The following total values of the basal area for individual stands per hectare were
obtained (Table 9): 27.1 m2 in Plot 1 (II age class), 25.0 nr in Plot 2 (III age
class), 31.6 iri in Plot 3 (IVage class), 30.5 nr in Plot 4 (Vage class), and 40.3 m2
in Plot 5 (VI age class).


The growing stocks of the stands per hectare (for timber mass of trees up to 3 cm
in diameter) are as follows: 204 m3 in Plot 1 (II age class), 272 m´ in Plot 2 (III
age class), 418 m3 in Plot 3 (IVage class), 426 m3 in Plot 4 (Vage class) and 617
m3 in Plot 5 (VI age class).


The current annual volume increment of stands per hectare is also high: in Plot 1
(II age class) it is 12.3 m´, in Plot 2 (III age class) it is 9.5 m\ in Plot 3 (IVage
class) it is 7.9 m´, in Plot 4 (Vage class) it is 9.2 m\ and in Plot 5 (VI age class) it
is 12.0 m1.


However, if structural elements of sessile oak are compared with yield tables, it
can be seen that almost all structural elements of sessile oak are lower than those
in yield tables (Tables 11, 12, 13, 14, and 15). When the distributions of breast diameters
of some species (hornbeam) are taken into consideration, then the differences
between managed stands and those mentioned are evident.


5. The yield tables by Spiranec are adequate for determining the normality of sessile
stands because timely and appropriate silvicultural procedures enable the
achievement of the sizes of structural elements that correspond to these tables.


6. The obtained data also correspond well to Cestar´s standards.


7. Since the tables of the cited foreign authors do not reflect the local ecological
conditions and since they were drawn up for both pedunculate and sessile oak,
their use is not recommended.


8. It is well known that apart from genetic factors, external factors of selection also
have a significant influence on the stand development. Therefore, expertly handled
intervention also has vital effects on the development trend. In these stands,
intervention is needed since their early youth, starting from tending and cleaning
to regular thinning treatments, which are indispensable for obtaining a better
quality increment, the formation of a stable stand structure and for preparing
them for natural regeneration.


Despite the small sizes of estates, the overall area of these forests is abundantly
large. These forests should be studied in more detail because they have an invaluable
role due both to their nonindustrial and economic functions.


The imperative of the sustainable management and the preservation of biological
diversity of the forest ecosystem demands that these forests be ensured all the prerequisites
that will enable the application of management principles aimed at improving
their condition and ensuring the sustainability of all their functions.


Key w o rds : sessile oak, forest of high silvicultural form, private forests, evena-
ged stands, site quality, growing stock, basal area, increment.