DIGITALNA ARHIVA ŠUMARSKOG LISTA
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ŠUMARSKI LIST 1-2/2009 str. 38     <-- 38 -->        PDF

Ž. Zečić, I. Stankić, D. Vusić, A. Bosner, D. Jakšić: ISKORIŠTENJE OBUJMAI VRIJEDNOST DRVNIH ...Šumarski list br. 1–2, CXXXIII (2009), 27-37


According to the assessment of forest condition in Croatia (ICP FORESTS)
for the year 1999, undamaged fir trees accounted for only 14.3 %, whereas
severely damaged trees accounted for as much as 63.8 %. Severe damage
denotes crown needle loss ranging from 26 % to 99 % (Potočić and Seletković
2000). Particularly high participation of damaged fir trees of 81.6 % was
recorded in Gorski Kotar in 1999, while only 3.8 % were healthy fir trees. The
results of field research suggest that the portion of damaged fir trees is constantly
increasing. Thus, as much as 88.4 % of severely damaged trees were
recorded in 2004 (Vrbek et al. 2008). The value of wood assortments of dead
trees from salvage cuts is lower compared to those obtained from regular silvicultural
treatments in healthy selection stands. The goal of this research is to
analyze the quantity, quality and value of wood volume obtained from salvage
cuts of silver fir in a selection forest.


The research was conducted in the area of Gomirje forest administration
within the management unit of “Potočine – Crna Kosa”. The management unit
extends over northern and north-eastern slopes of Mt. Velika Kapela at altitudes
between 339 and 1,200 m. The compartment covers an area of 36.00 ha.
The management class is a managed forest of silver fir and common beech with
a total growing stock of 339 m3/ha. The growing stock of fir is 112 m3/ha. There
are 304 trees per hectare, of which 157 are silver firs. To investigate fir trees
during salvage cuts, breast diameters and heights were measured on every blazed
tree and crown damage was directly assessed using the ICP FORESTS methodology.
Trees marked for cutting were divided into two classes (degrees) of
crown damage (“3b” and “4”). Crown damage for class “3b” ranges between
81 % and 99 %, while class “4” represents completely dry trees (Figure 3). The
volume of each marked tree was calculated according to the Schumacher-Hall
expression.


Values of wood and timber assortments change in accordance with changes
in the society, on the market and in economic relations, and in accordance
with the application of new technologies and impacts of other factors (Rebula
1996). Value analysis of the obtained wood volume is made by determining
the price of every single timber assortment. The price of every single piece of
roundwood corresponds to the valid pricelist of the main forest products. The
pricelist is used to calculate the price of roundwood from forests owned by the
Republic of Croatia during the sale of standing trees (“on the stump”) to contractual
buyers. Value coefficients were established in accordance with
mutual relations of price classes in relation to the most represented price
class, which was taken as 1.00. The results were expressed by the relative
value ratio of timber assortments produced from trees in crown damage classes
“3b” and “4”.


Figure 3 shows distribution of dead silver fir trees in compartment 7b with
regard to crown damage degree. Diameter classes range from 17.5 cm to


77.5 cm. The lowest number of trees, i.e. only one tree, was in the largest diameter
class, while the majority of the trees were in the diameter class of
47.5 cm. A total of 200 trees with average breast diameter of 48 cm and average
height of 29.4 m were marked and processed. A comparison of the total
marked volume determined with the Schumacher-Hall form and the volume
taken from the mentioned tables is given in Figure 5. The comparison wasmade on the basis of individual and total tree volume. According to Šurić, the
total volume of marked trees was 491.93 m3, according to Schuberg it was
570.32 m3, and according to Schumaher-Hall it was 570.95 m3. Statisticallysignificant differences (for p<0.05) were found in Šurić – Schuberg and Šurić
– Schumacher – Hall relations, whereas insignificant difference was found in
the comparison of volume of Schuberg – Schumacher–Hall.