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HR  EN   



Scientific-technical and professional journal
of Croatia Forestry Society
                         Issued continously since 1877.
       First issue of this web edition start with number 1-2/2008.
   ISSN No.: 1846-9140              UDC 630*https://doi.org/10.31298/sl

Portal of scientific
journals of Croatia
   Issued by: Croatian Forestry Society

   Address: Trg Mažuranića 11, HR-10000 Zagreb, Croatia
   Phone/fax: ++385 1 4828477
   e-mail: urednistvo@sumari.hr
   Editor in Chief: Branimir Prpić

Branimir Prpić   101
Several important dates related to environment protection were listed in an article entitled In Step with Nature, a special supplement toSensa,the magazine for a happier life.This reminded us of the great, but oftenoverlooked importance of forests, which is marked on three March dates: Forest Day on March 3,World WaterDay on March 22, andWorld Meteorological Day on March 23. The supplement gives a pessimistic outlook onthe future of our planet, which is richer by 78 million people every year. It warns of the increasing natality rateand the impending lack of food, water and energy for over one third of the human population.
The authority that highlighted and marked the three areas of environment protection mentioned above alsoproposed a logical sequence of subjects to be discussed on these three days, as well as pointed to their interdependence.According to a number of predictions, drinking water will become one of the most desired commodities in the future.We are very lucky to be the fourth richest country in Europe in terms of water.The largesupply of water is closely connected with natural state forests, which account for about 80% of all forests inCroatia.We also abound in rivers with almost natural flows. The regulation of large floodplain areas of LonjskoPolje and Mokro Polje has ensured protection against floods for the City of Zagreb and the towns, villages andhouseholds situated downstream of the rivers Sava, Kupa and their tributaries.We have also established the Nature Park of Lonjsko Polje with about 30,000 ha of lowland forests and about 20,000 ha of pastureland.The diverse plant and animal world makes this area unique in Europe.
The structure and the rich, live forest soil function as mechanical, biological and partly chemical purifiers ofprecipitation water and of flood water in lowland areas.Thus purified, the water enters underground flows andsupplies water sources.All Croatian rivers that spring in the Croatian Dinaric range are drinkable at their source,whicheo ipsorepresents huge potential of drinking water.With the addition of all their streams and forest sources, this is an immeasurable, practically priceless value which we have so far done almost nothing to put to gooduse.The Black Sea watershed, enriched by the water flows of the continental part of Croatia, is an additionalbonus.According to Mitscherlich from Otto 1994, of the overall amount of water that reaches the forest throughprecipitation, one part filters through the soil and supplies underground flows with drinking water. During thevegetation period, this accounts for 30 to 40 % and during the dormant period for 70 to 80 % of the amount.
Taking an average of 1,200 mm of precipitation in Croatia, the 2 million ha of fully canopied forests theoretically purify about 13 billion tons of drinking water annually. How much of this amount we will use depends onour needs and on good technologies.
The connoisseur who listed the days of forests, water and meteorology in this order must have had in mindthe dependence of forests on water and the influence of both on climate change and vice versa.The role of theforest, which mitigates the glasshouse effect in the atmosphere through its function of carbon sequestration,comes to its full effect here. This effect is certainly more pronounced in Croatian natural forests than in European spruce monocultures.
In addition to ensuring drinking water, the forest also stops and mitigates high water waves. Aforest willsuccessfully intercept as much as 100 mm of precipitation fallen on a single occasion.The forest will still exertits effect up to150 mm, but not over this amount.
There is a deeper intention in putting together forests, water and meteorology.We propose that the ForestDay, the World Water Day and the Meteorological Day be marked by a different institution every year in theform of a scientific symposium with Croatian and foreign cooperation.We propose that the symposium for theyear 2011 is organized by forestry, for the year 2012 by Water Management, and for the year 2013 by the StateHydro-Meteorological Office.
The time has come for holding a discussion within a broader state framework concerning irrigation of agricultural land for the purpose of producing pure ecological food. Such food will certainly find its buyers on theEuropean market.Water for irrigation should not be taken from the polluted rivers of Sava and Danube, butshould be pumped from water retentions on Psunj, Papuk and Dilj and brought to the fields by pipes using theforce of gravity.

Professor Emeritus Branimir Prpić, Ph.D.

    PRPIĆ, Branimir    ŠL
Zečić,Ž., D. Vusić, M. Prka, S. Klepac  UDK 630* 377 (001) 103
Influence of Skidding Road Slope on Productivity of Skidding Timber Assortments with Tractor Timberjack 240C in Selective Forests      
Summary: This paper presents results of research of Timberjack 240C tractor equipped with double-drum winch Adler HY16 in skidding timber asortments up and down the slope in selective felling.
The work site is situated on the altidude between 870 m and 1097 m. Harvesting density was 51.86 m3/ha. Structure of growing stock was: 74.29 % of fir, 22.87 % of beech and 2.84 % of other hard broadleaves.
Ž. Zečić, D. Vusić, M. Prka, S. Klepac: UTJECAJ NAGIBATRAKTORSKOG PUTANAPROIZVODNOST ...Šumarski list br. 3–4, CXXXIV (2010), 103-114
Harvesting phases of felling and processing were time-separated from skidding.
Research was conducted using time and work study method. Time consumption of each work component was measured by snap-back chronometry method. Lenght of skid roads was gradually measured on uniform slope segments by GPS. Coordinates of points, where the longitudal slope changes, were recorded by GPS as well. Slope of each individual segment was calculated using the difference in altitude of slope change points and the related lenght.
While skidding, the tractor was travelling exclusively by two skid roads (figure 4 and table 1). Average skid slope is expressed in percents, in the direction of loaded tractor travel. Average slope of recorded turns was calculated by weighting the related slope with the travel lenght. Average skidding distance was calculated as an average of recorded loaded trevel lenghts of each turn.
Load records are shown in table 2. Significant difference in average load on skid trail 1 (5.043 m3) and on skid trail 2 (3.715 m3) is evident. By each turn difference in productivity of skidding on skid road 1 and skid road 2 increases by 1.328 m3. During the research 75.650 m3of beech wood asortments, and 115.994 m3of fir wood asortments were skidded on skid road 1. On skid road 2 18.607 m3of beech wood asortments an 44.549 m3of fir wood asortments were skidded. By multiplying achieved volumes with density of fresh beech wood (1,07 t/m3) and fresh fir wood (0,98 t/m3) average load masses on skid road 1 (5.122 t) and on skid road 2 (3.739 t) were calculated.
Variable times (travel loaded and unloaded by skid roads and landing, line pulling and winching) were analysed by mathematical and statistical methods (figure 6, figure 7 and figure 8). All other effective times were regarded as fixed and calculated as averages of recorded time (figure 11).
During the research average daily output of 36.40 m3/day was achieved with average total time consuption of 404,59 min/day. The said total time consumption makes 84.59 % of legal working time (480 min). With full utilisatin of legal working time, at the same organization of work, the productivity would increase by 15.41%.
During the research the tractor accomplished 76.46 % of total time as efective time with delay time of 23.54 %. In effective time per turn, for skidding distance of 500 m, fixed times take 17.36 min and variable times take 18.97 min. Effective time per turn, for skidding distance of 500 m, is 36.34 min. With determined allowance time factor of 1,22 total time is 44.42 min. Average travel speed on skid roads is 3.56 km/h for unloaded tractor and 3.50 km/h for loaded tractor. Average travel speed on landing is 4.65 km/h for unloaded tractor and 4.93 km/h for loaded tractor, on average distance of 65 m. Average speed of line pulling is 0.97 km/h and average speed of winching is 0.86 km/h. Standard time of skidding on skid road 1 ranges from 5.32 min/m3(100 m) to 13.17 min/m3(1000 m) with average load of 5.04 m3. For skkiding on skid road 2 standard time ranges from 7.22 min/m3(100 m) to 17.88 min/m3(1000 m) with average load of 3.72 m3.
Daily output ranges from 90.27 m3/day for skkidnig distance of 100 m to 36.45 m3/day for skidding distance of 1000 m, when skkiding on skid road 1, and from 66.50m3/day to 26.85 m3/day when skidding on skid road 2 for the same distances. For skidding distances from 100 m to 1000 m skidding cost ranges from 31.83 kn/m3 to 78.83 kn/m3, for skid road 1 and from 43.20 kn/m3to 107.01 kn/m3for skid road 2.
Timberjack 240C tractor belongs to a group of highly-efficient special forest timber skidding machines. The principle of load size effect, as one of the key factors of timber skidding, on skidding productivity in different skidding distances has been proven by this detailed research. Hence, by increasing the load volume the productivity of this tractor is significantly increased, thus lowering the cost per unit, in this case by 26.34 %. Considerably lower timber skidding cost when skidding down the slope should be regarded as one of the capital elements in planning and construction of secondary forest network.

Key words: cost; productivity; skidder; skidding; slope

    ZEČIĆ, Željko      ŠL
    VUSIĆ, Dinko    ŠL
    PRKA, Marinko      ŠL
    Klepac, Saša
Ostrogović, M.Z., K. Sever, I.Anić  UDK 630* 231 (001) 115
Influence of Light on Natural Regeneration of Pedunculate Oak (Quercus roburL.) in the Maksimir Forest Park in Zagreb      
Summary: In a forest park Maksimir, in a mixed forest stand of Pedunculate Oak and Common Hornbeam (Carpino betuli-Quercetum roboris/Anić 1959/ Rauš 1969), influence of light conditions on number and quality of young oak growth was investigated. Experimental plot covered two regeneration gaps and the space between, including the trees in a different stage of development (seedlings, saplings and young trees). Measurements were taken in the winter 2006 and spring 2007 in a single plot within the stand. The plot was divided in 105 sub-plots of 1.5 m x 1.5 m and on each sub-plot height (cm), tree length (cm), ground level diameter (mm) and last five height increments (cm) were measured. Parallel to the measurement, evaluation of stem quality, crown form and tree health state was conducted. Spatial distribution of old grown trees at the plot area, together with crown projections, was recorded. At each sub-plot a hemispherical photograph was taken. Average annual relative values of diffuse and direct light for different development stages of Pedunculate Oak were determined. Depending on the values of diffuse and direct light, four microsites (marked: A – D) with different light conditions were defined.
Results indicate that natural regeneration in naturally occurring gaps could be considered successful. Average number of trees per square meter was 8.3. Species composition of naturally occurring young trees in the gap indicates a continuation of the same forest community, namely mixed forest stand of Pedunculate Oak and Common Hornbeam with a smaller share of Wild Cherry (Prunus aviumL.), Hedge Maple (Acer campestreL.), Norway Maple (A.platanoidesL.) and Lime (Tiliasp.). Mixed forest stands are of great biological and ecological value, but also attractive to the park visitors. Maintaining them and their stability is a main management goal in this forest park. However, in naturally occurring gaps in the absence of silvicultural treatments the quality of young trees is questionable. High density of young growth at our plot resulted with high tree slenderness coefficient of 97,7. Share of deformed tree stems was significant (30.3 %), as well as share of badly developed tree crowns (44.3 %). Great abundance of weed vegetation was recorded and can be attributed to the lack of silvicultural treatments during regeneration. Chi-square test showed statistically significant dependence of number of young oak growth in different development stages with respect to the light conditions at microsite. Lower values of direct and diffuse light (microsite C) correspond with great number of oak seedlings. Surviving of oak seedling in low light conditions confirms the fact that in first few years oak is shade tolerant. However, great abundance of oak saplings at microsites A (lower values of direct and higher values of diffuse light) and D (higher values of direct and lower values of diffuse light) indicates that oak, when it arrives to the stage of saplings, favours higher light conditions. This is further corroborated at microsite B (with high values of direct and diffuse light) where young oak trees were most abundant. Quality of oak saplings and young trees was better at microsite B. Young oak trees grown in high light conditions obtained greater height increment and stem verticality. High positive correlation is obtained between Pedunculate Oak average height increment and average values of direct light (r = 0,5809).

Key words: development stages; direct and diffuse light; quality of young Pedunculate Oak growth.; regeneration gap

    Ostrogović, Maša Zorana    ŠL
    Sever, Krunoslav
    ANIĆ, Igor      ŠL
Jambreković,V., R. Despot, M. Hasan  UDK 630* 841 (001) 125
The Overview and Evaluation of Phytosanitary System in CompaniesAuthorised for the Treatment and Marking of Wooden Material for Packaging in International Trade      
Summary: Because of the portability of the quarantine pests away from their usual area, under the auspices of the World Trade Organization (WTO) and the World Organization for Food and Agriculture (FAO), International standard ISPM 15 was made and accepted. ISPM 15 provides methods of treating wood packaging in international traffic which application reduces the risk of entering and / or spread of harmful quarantine organisms using the wooden material. By adoption of The rules of the phytosanitary requirements to be met by wood packaging material in international transport (Pravilnik o fitosanitarnim zahtjevima kojima mora udovoljavati drveni materijal za pakira nje u međunarodnom prometu, NN 14/06), Republic of Croatia also incorpo rated standard ISPM 15 into their legislation. During the five-year activities phytosanitary system was established, and 84 companies are authorized to independently conduct heat treatment (HT) and to mark wooden packaging materials. Companies are well distributed throughout Croatia, which allows the Croatian economy unimpeded international trade of goods. During phytosanitary inspection, in the 67 authorized companies it has been found that all the companies properly carry out the heat treatment, while the main problems arise in the development of the Manual of authorized companies, traceable records, maintaining and certifying measuring equipment and marking of wooden packaging materials in international commerce. Observed deficiencies are mainly internal in character and have not caused adverse effects in international traffic. Following record of phytosanitary inspection, companies are obliged to remove the perceived shortcomings before the next inspection.

Key words: heat treatment (HT); ISPM 15; marking; phytosanitary inspection; phytosanitary system; wooden material for packaging

    JAMBREKOVIĆ, Vladimir    ŠL
    DESPOT, Radovan    ŠL
    HASAN, Mario    ŠL
Pezdevšek Malovrh, Š., L. Zadnik Stirn, J. Krč  UDK 630* 682 (001) 139
Influence of Ownership and Property Structure on Willingness of Private Forest Owners to Cooperate      
Summary: Private forest management is, particularly in Slovenia, far from optimal. The reason lies in the diversity of ownership and property structure. In addition, Slovenian private forest owners are not adequately organized and associated to manage their forests. The willingness of private forest owners to cooperate was evaluated using the questionnaires. The sample (n=700) included equal shares of associated and non-associated owners. Forty-six percent of questionnaires were returned. The results of the survey analysis showed that 39.1 % of private forest owners were members of forestry associations (associated), 19.9 % owners showed willingness to cooperate i.e. to join a forestry association and 41.0 % of the sampled forest owners were unwilling to cooperate. Based on the data obtained through the survey we have studied the relationship between ownership and property conditions in regard to the willingness of forest owners to cooperate. The Chi-square test showed the statistical significance of the relationship between the size of forest property and the willingness of owners to cooperate. Further, the results of multivariate logistic regression showed that it is necessary to search for private forest owners who are willing to cooperate in the group of forest owners who are younger than 50 years, who own more than 10 ha of forest land and live in common household with the co-owners.

Key words: bivariate and multivariate analysis; forest owners’ cooperation; logistic regression; ownership and property conditions; private forests; statistical models

    Pezdevšek Malovrh, Špela    
    Zadnik Stirn, Lidija    
    Krč, Janez    
Posarić, Darko  UDK 630* 440 + 450 151
The most Important Reasons for the Loss of Pedunculate Oak (Quercus roburL.) from Forest Stands up to First Thinnings      
Summary: During the process of natural regeneration of pedunculate oak (Quercus roburL.) forests, and later during a growth of young plants, up to the age of approximately 20 years of old, many oak plants die out. This paper will not deal with those oak trees which, in the struggle for light with other oak plants die during the growth of the stand. This is a normal, natural process. Paper will deal with the reasons for excessive loss of oak plants and disruption of the normal tree species ratio in lowland oak forests and ways to prevent these losses.
Many unfavorable factors are causing a decline of oak plants. Their sequencing and/or synergic action is a reason that many oak plants die out. If the natural regeneration of the stand is well managed, and if the adverse impacts are controlled all the time to the first thinnings, it is very likely that there will be a high quality oak stand. However, if the foresters come too late with the protection of the stand at any stage of its growth, or even fails to do it, oak plants suffer. It is therefore very important to protect and tending young stand well up to the age of the first thinnings.
The adverse impacts that endanger oak plants are numerous and diverse. The most harmful are retaining surface water, small forest rodents (especially vole species – Figure 4) and competitive weed vegetation (Figures 3 and 5). Some influences are under the permanent supervision and there is a quality protection against them (e.g. Oak mildew – Microsphaera alphitoidesGriff. et Maubl.) and because of that they are not causing much damage, although they are potentially very dangerous. Some others are underestimated and therefore their harmful impact occurs, especially after the removal of the old stand by final cut, when monitoring and control of the young stand are not so intensive as they were during the regeneration process. A need for permanent professional supervision and control of the stands state is the most important conclusion of this work, because they are a prerequisite for timely and proper response to the observed adverse impacts.
Keywords: the die out of oak plants, seedling stage, sapling stage, young forest, prop stage, retaining surface water, small rodents, vegetation of weeds, monitoring the situation of stands.

    POSARIĆ, Darko    ŠL
Ivančević, Vice  UDK 630* 902 159
The Rich Museum Tradition of Croatian Forestry Continues - On the occasion of opening the Forestry Museum in Krasno, the first in our country      
Summary: The establishment of the Forestry Museum in Krasno in 2005, the first of the kind in Croatia, filled a large void in museum presentation of the forestry profession. This event was shortly followed by the opening of the Forestry Museum in Bošnjaci in 2007. These two museums cater for three important segments of our forestry; high selection forests and littoral karst (Krasno) and lowland regular forests (Bošnjaci). Their foundation marked a big step towards more progressive museum presentation of our forestry and wider popularization of our profession. Visitors to the Forestry Museum in Krasno are given the opportunity to gain insights into forestry through past periods. Still, the activity of the Museum needs to be complemented with detailed research into the history of forestry by means of organizing professional gatherings, collecting new exhibits and documentation, introducing up-to-date presentation techniques and possibly enlarging the museum.
However, such “regional“ forestry museums can in no way replace one central forestry museum in Zagreb. One such museum used to be housed in the Forestry Home in Zagreb from 1898 to the end of World War II. The non-existence of a central museum which would present the entire forestry of our country is a big handicap for our profession. This is the reason that its reopening in the former premises in Zagreb takes priority. Furthermore, it is a debt of the current generation of foresters towards our forerunners, but also towards the entire forestry profession.
We have selected some of the most important data from the meticulously described holdings and principal exhibits in the Forestry Museum in Krasno. The museum in situated on the ground floor of an old but renovated building of Krasno Forest Office. It contains four rooms and a corridor with a sanitary block in the area of 131 m2. Together with a smaller, detached porch of 34 m2, the overall area amounts to 165 m2. A total of 357 exhibits have been collected, of which 162 relate to different written documentation (pictures, maps, studies, ledgers, specialized books, brochures and others) and 195 exhibits show a variety of work equipment (instruments, tools, appliances and products). The library contains 556 items in all (326 books and 230 brochures). Satisfaction with the work of the Krasno Forestry Museum to date and a keen interest shown by the wider public commit us to invest further effort into enlarging its contents and following the presented recommendations.

Key words: exhibit; forestry disciplines; Forestry Museum in Krasno; work equipment; written documentation

    IVANČEVIĆ, Vicko    ŠL
Roša, Jadranka  UDK 630* 892 169
Steps to the Eco-label for Therapeutical Herbs andAromatic Plants      
Summary: Diverse relief and various climatic features have influenced on development of great number of plants species in Croatia. A therapeutical herbs and aromatic plants has always played important role in traditional medicine. Recently there are growing interests in collecting and producing therapeutical herbs and aromatic plants, what is an effected by ecological approach and protecting of environment and health. About 170 therapeutical and aromatic plants are collected or producing in Croatia. Natural geographical and soil conditions in Croatia make possible successful growth health and aromatic plants. Only plants cultivated on ecological manner or collected from clean area without sources of pollution in their neighborhood have particular validity. Republic of Croatia has good condition related to protected area and biological diversity and lot of the therapeutical herbs and aromatic plants that are very valuable ecological products.

Key words: biological diversity; Croatia; ecological label (eco-label); ecological production; therapeutical herbs and aromatic plants

    ROŠA, Jadranka      ŠL