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ŠUMARSKI LIST 5-6/1997 str. 32     <-- 32 -->        PDF

S. Matić, B. Prpić: PROGRAM NJEÜE, OBNOVE I ODRŽAVANJA TE EKOLOŠKE I SOCIJALNE FUNKCIJE PARK SUMA...
SUMMARY: Today´s park forests of Zagreb are the remnants of the ancient
natural forests that covered today´s urbanized Zagreb area. This paper describes
17 parks covering altogether 1,258.55 ha, while all park forests of Zagreb
amount to 2,400 ha.


Greatly retaining their natural composition, Zagreb park forests stretch
along the Sava valley and the southeast hillsides of the mountain Medvednica.
On the hills grow the sessile-flowered oaks and submontane beeches. In the
Sava valley thrive the pubescent oak forests, while the willow and poplar associations
appear wherever there are floods.


Woven throughout the city, these precious forests raise the question of how
to tend them. Protected by law, though not by their genesis, structure and development,
they do not differ from the classical management forests, except for
the management targets. Park forests serve only for ecological and social purposes,
i.e. hydrology; fight against erosion and pollution; in terms of their climatic,
recreational and health functions.


The silvicultural topics of this paper have been dealt with in phases, which
include the revitalization steps such as improvements of the soil for natural regeneration,
and if necessary, artificial supplements, young stand protection,
tending of young trees and stands by clearing and thinning, as well as other
operations that improve the social and ecological forest functions.
Suggestions for silvicultural care of all 17 park forest areas have been given.


The ecological and social forest functions are described with the criteria
for the evaluation of the generally valuable functions, so that the total value of
all 17 areas amounts to over 4 billion kunas (1.13 billion DEM).


The following conclusions have been made after the research done in the
Zagreb park forests:
1) The management methods used for park forests and those for common


forests differ by their targets. The latter improve the technical value of the
trees while supporting the value of the ecological and social forest functions.
In the park forests, the focus of the operations is the improvement of their ecological
and social values. Crucial is the maintenance of the biological diversity
by supporting the mixed stands consisting of the trees corresponding to the
given habitat.


2) In order to stimulate the binding of the carbon dioxide and the release of
oxygen in the process of photosynthesis, a high producibility of the ecologically
balanced forest stand should be sustained. This target can be met by normal
measures of the classical silviculture, adjusted to the purposes of the park


forest.
3) Even-aged or regular park forests, either low, medium or high in their
silvicultural form, should be renewed in a combined way. In most cases,this is
done by the procedures of the regeneration cuts on small areas combined with
the regeneration through fringe cuts with relatively long regeneration periods.
The reason for regeneration is the physiological age of the trees with the disturbance
of the physiological processes, which reduces the ecological forest
value (reducedphotosynthesis, increased transpiration and breathing).
4) Single social functions of the park forests should be thoroughly investigated
for their quantification in terms of planning forest protection (soil treading,
tree damage, etc.).
5) Considering the extremely unfavourable chemical impacts of the wet
toxic sediments, the damage degrees on the selected bio-indicative points
should be established before deciding on the change of habitat and the appropriate
measures.


Šumarski list br. 5-6, CXXI ( 1997), 225-242