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ŠUMARSKI LIST 7-8/2004 str. 44     <-- 44 -->        PDF

M. Prka: DEBLJINA KORE OBIČNE BUKVE (Fagus srlvatica L.) U SJEĆINAMA BJELOVARSKE ...
SUMMARY: Smooth and thin bark is one of very prominent morphological
features of common beech. Because of particular activity of cork cambium
(phellogen) beech bark follows thickness increment, and it does not peel off
and crack on the surface.


Research of bark of domestic tree species in Croatia started in the 1850s,
and in the beginning, species with thicker bark attracted more attention.


Structure and appearance of bark often vary considerably, even in trees of
the same species, if they grow in different conditions. Specific features of bark
variability are genetically determined. Researching bark thickness of beech
trees in the area of Bjelovar Bilogora, we noticed specific variability in beech
bark morphology.


Empiric cognitions of forestry operational bodies in the researched area
tell us that beech trees with furrowed (rough) bark are less inclined towards
creating false heartwood (kern). That assumption has not been tested primarily
because of small number of such trees in the researched area.


Of all the bark features, the most important is its thickness. That results
from the fact that we produce technical roundwood offoliaceous trees, pull it
and transport it with bark, but we measure it (take it over) and ship it without
bark. In that way, bark offoliaceous trees in technical roundwood is specific
ballast in production, which does not give financial results.


So far, research of beech bark thickness (Krpan, 1986) has established
some generally accepted regularities:


-
Bark thickness is in direct relation to tree or roundwood diameter.
-
Bark thickness decreases from the tree stump towards the top of the tree
trunk.
-
Bark thickness increases with roundwood thickness, while the percentage
of thickness and the volume decrease.
Also, poor natural settings cause greater bark thickness.
Double bark thickness was measured at breast level of the tree, then in the
middle of each log, and in the middle of every fifth round log of firewood.
Bark sample was taken from the specified places by a little axe, to make sure it
is big enough and to avoid its bruising. Bark thickness was measured by
micrometer calliper with nonius correct at 0.1 mm. Total bark thickness value
was obtained by adding the measured values of bark thickness in samples
taken from the opposite places on the roundwood cover.


The research included 2,106 sample trees on 30 research objects in total
number of 34 occasions (fellings), with 18,381 pairs were measured for double
bark thickness and breast diameter, or diameter in the middle of the item.


We researched bark thickness in relation to common beech diameter in
thinning and seeding fellings of beech-cutting areas in the economic unit
Bjelovarska Bilogora. We analysed the average percentage of bark in the volume
of technical roundwood, with regard to type of felling of seeding beech
fellings.


Data on double bark thickness in relation to breast level diameter of the
tree were equalized by regressive linear equation with very strong correlation.
Values of double bark thickness in relation to diameter in the middle of
technical roundwood and round logs were equalized according to type of
felling by regressive linear equations with strong and very strong correla


tinnv


It has been established that there are not any significant differences
between the values of double bark thickness in relation to thinning, preparatory,
seeding and final felling, so that the values of double bark thickness and


Šumarski list br. 7-8, CXXVIII (2004), 391-403