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ŠUMARSKI LIST 13/2011 str. 264     <-- 264 -->        PDF

E. Paladinić, D. Štimac, H. Marjanović, I. Balenović, M. Z. Ostrogović: SUŠENJE OBIČNE JELE (Abies alba Mill.) ... Šumarski list – Posebni broj (2011), 248-263


Forest Administration Branch Delnice i.e. forest area affected by intensive fir
trees dieback. The stands in focus represent main fir-beach forest community
in Gorski Kotar, Abieti-Fagetum illyricum Ht. Research activities on field
data acquisition were started in forest management unit “Brloško”. Data
about forest compartments included in research are presented in Table 1.


Results of research and discussion. Firstly, the results of H1 are presented
and discussed. Statistically significant differences between planned and realised
volumes were confirmed for veneer assortment, for all forest compartments
except one. The results were expected because five of seven compartments are
considered as stands of significantly disturbed health condition, where possibility
for production of high quality timber assortments from fir trees is minimal.
Another fact considerably affects on differences between planned vs realised
timber assortment structure is assortments tables, according to which each
tree with dbh higher than lowest threshold for veneer class gets certain veneer
volume from tree volume. Veneer volume participates in the whole sample of
produced timber assortment volume with 0.59 %, and concerning forest compartments
from 0.00 % to maximum 3.01 % (see Table 2).


T-test results for 1st class saw logs confirmed discrepancies between realised
and planned quantities for all forest compartments except compartment
no.15 in forest management unit “Brloško” (t value is 0.80). Volume of 1st
class saw logs participates in the whole sample of produced timber assortment
volume with 5.85 % to 35.95 %, concerning forest compartments. Different
from previous, t-test for 2nd class saw logs confirmed discrepancies between
realised and planned quantities for three forest compartments, two representing
category of good health condition, and one category of worse health condition
(table 3). Volume of 2nd class saw logs participates in the whole sample
of produced timber assortment volume with 13.93 % to 31.28 %, concerning
forest compartments. Testing volume of 3rd class saw logs confirmed discrepancies
between realised and planned quantities for four forest compartments
(two in category of good health condition, and two in category of worse
health). This assortment class after pulp-wood and firewood has the highest
share in whole sample volume of assortment classes. Volume of 3rd class saw
logs participates in the whole sample of produced timber assortment volume
with 16.29 % to 36.90 %, concerning forest compartments.


The most frequent timber assortment is pulp-wood and firewood category,
leading by number of logs. This fact is in line with disturbed wood quality of
standing fir trees which are in process of dieback or completely dead trees in
the felling moment. Analysing discrepancies between realised and planned
quantities for this assortment category, tests confirmed statistically significant
difference for all forest compartments except one. Tested wood volume of the
category participates in the whole sample of produced timber assortment volume
with 6.38 % to 54.41 %.


Recovered wood (i.e. wood residue) assortment is problematic because of
its technical inapplicability. This assortment category consisted of small number
of pieces, and according to assortment tables each tree gets certain volume
of the assortment (so called wood waste). This discrepancy is supported
with T-test results confirming significant differences between realised and
planned quantities for all forest compartments. Hence, further consideration
of the recovered wood assortment was cancelled.


Regarding to obtained results, it can be concluded that H1 is accepted because
statistically significant differences have been confirmed for majority of
tested combinations. Testing H2 by ANOVA and T-test, for each assortment
class were confirmed differences between assortment volume variances comparing
two health categories of stands (table 4). Other words, the relationship