DIGITALNA ARHIVA ŠUMARSKOG LISTA
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|ŠUMARSKI LIST 3-4/2008 str. 43 <-- 43 --> PDF|
S. Matić, D. Delač: UZGOJNI ZAHVATI KAO MJERA POVEĆANJA VRIJEDNOSTI PRIVATNIH ŠUMA ...
wing stock in the stand. If the growing stock is higher than normal, cutting intensity
should not exceed 30 %. If it is lower, cutting intensity may be reduced
to 15 %. This is borderline intensity which should not be exceeded. This means
that cutting should be postponed until another cutting cycle is over, in this
case another 10 years. Higher or lower intensities could endanger the selection
structure, i.e. the increment, regeneration and stability of the selection
stand. Inappropriately applied intensities cannot maintain a selection stand
in the optimal structural conditions which will ensure maximal production
and optimal regeneration. Regrettably, this is one of the most serious current
problems in selection management and selection forests.
Beech and spruce stands which have officially been classified as uneven-
aged stands and which have not been managed selectively but with selection
cuts show a negative developmental trend. This kind of management results in
decreased growing stock, absence of natural regeneration, reduced tree quality
and lower increment.
In such stands management based on regular principles should be organized
over small areas (each structural unit – special silvicultural treatment)
Silvicultural treatments are spatially divided over small areas. In other
hh structural unit represents a special part of the stand which requisilvicu
res a specia
ll silvicultural treatment. They are spatially separated but temporally
Management with shelterwood cuts in small areas with a longer regenerachieve
tion period achieves
dd spruce forests. This type
o gooof regeneration
aa good yield of seeds of the
principal and other tree species and the survival of their young generation
Regeneration in regular forests is generally done in 3 cuts (preparatory,
seed and final) and less frequently in 4 or 5 cuts, where subsequent cuts are
introduced. The preparatory cut is undertaken with 20 % intensity and the
seed cut with 50 % intensity in a good seed year. The remaining wood volume
is cut as needed, either with one or two subsequent cuts or, more frequently,
with one final cut.
Regular forests are tended throughout the life cycle of the stand, that is,
until the shelterwood cuts are applied. Tending consists of the following stages:
tending of the young growth after the final cut, cleaning in the developmental
stage of the young growth and saplings, and tending with thinning.
Tending of the young growth after the final cut is usually done once only,
while cleaning or negative selection is done once or twice until the moment
the stand reaches its maximal height increment. At this stage future trees are
identified, which in beech and spruce forests takes place around the age of 30.
At this age stands may be tended with thinning.
Coppices of beech, pubescent oak and other hard broadleaves are regenerated
with shelterwood cuts. The goal is to convert a coppice into the forest of
high silvicultural form or seed forest.
Regenerating a coppice with clearcutting and planting conifer species is a
serious mistake. Conifers
ss may be planted in degraded forest soils which have
lost the properties that
tt provide the parent climatogenic stand with optimal
conditions for growth and development.
Coppices should be tended throughout the rotation period.
The tending stages in a coppice include reducing the number of poor quality
and superfluous shoots on the stump, tending coppices with cleaning or
negative selection, and tending coppices with thinning or positive selection.
In the current economic and social conditions in Croatia arable areas are
systematically being reduced and the size of abandoned agricultural land is
Šumarski list br. 3–4, CXXXII (2008), 121-146