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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: Josip Margaletić

Uredništvo   337
Parafiscal levies – definition and who should pay them      
A new change referring to the payment of non-market forest function fees, regarded as a parafiscal tax, urges us to again discuss this problem. We read on the Entrepreneurial Portal: Although officially called "non-tax benefits", the term "parafiscal levies" has already become commonplace in the public, and 161 parafiscal levies have been listed, which is believed to take away about 2.5 % of the GDP from the nation. A more detailed explanation according to the definition of the Ministry of Finance states: "parafiscal levies are all prescribed mandatory non-tax benefits paid by companies to central state administrative bodies, local and regional self-government units or other bodies with public authority, if the payer does not receive a service, goods or right in return ...". If so, then why is the non-market forest function fee treated as a parafiscal levy? In this case it is indisputable that the payer receives a service, goods or right in return. It should be clear to everyone who reads the Forest Act and where the non-market forest functions are listed as follows: 1. protection of soil, roads and other facilities from erosion, torrents and floods; 2. impact on water regime and water quality; 3. impact on soil fertility and agricultural production; 4. impact on climate and mitigation of climate change; 5. protection and improvement of the human environment; 6. oxygen generation, carbon sink and atmospheric purification; 7. recreation, tourist and health function; 8. creation of favourable conditions for wildlife and other fauna, and 9: increased impact of protective forests and special purpose forests on biodiversity. Some of the functions provide benefits only for some individuals, while other functions provide benefits for all. The non-market forest function fee initially amounted to 0.07 % of the total annual income, in 2010 it dropped to 0,0525 %, and then in 2012 to 0.0265 %, whereas in 2018 all those who generated total income less than 3 million kuna annually were exempt from payment. Now all these with a total annual income of less than 7.5 million kuna are exempt from payment, and the percentage has dropped to 0.024. To make it clearer, let us calculate how much money it is per year - at 3 million kuna it was 795.00 kuna/year, and at 7.5 million kuna it was 1,800.00 kuna / year (what an amount!). In view of the chronology of the reduction of the non-market forest function fee and the hysteria surrounding parafiscal levies, it would not at all surprise us if, after the parliamentary elections, the government completely abolishes this, in our view, necessary and environmentally progressive tax. Regrettably, it would not be the first time that populism takes steps that are not good either for the state or for the society.
The main economic activities, including 1. production of wood forest products, 2. production of forest reproductive material and 3. production of non-wood forest products, are expected to generate income which is paid into the state budget. All this despite non-market business moves in the trade of these products and the necessary need for timely and comprehensive work on silvicultural and protection operations in the forest ecosystem, which are often "skipped" in order to maximize profit. We have repeatedly pointed out that there is no profit in forestry if we return to the forest what we have taken from it so as to leave it in the optimal state, or figuratively speaking, so as to make it "eternal". We have often discussed every one of the nine non-market functions listed above, corroborating our words with research results. The numbers are impressive and are easy to remember. Due to limited space in the column, let us only take the hydrological function; no vegetation form affects water as effectively as a forest - it balances the distribution of water in space, evenly supplies watercourses and mitigates high water waves, and affects water purity and the number of water springs. Water filtered through live and friable forest soil reaches ground courses as potable water. If we take into account the average annual rainfall in Croatia of 1200 mm and the forest area of only 2 million ha (it is larger), it is calculated that about 13 billion tons of drinking water flows from the forest. Who receives this service? Everyone, including the payer! We could continue in the same way with other non-market forest functions. Some would say, these issues have been treated at a number of forestry conferences, but we foresters speak for ourselves - and we ask our colleagues: you have been served information in this column and in other articles - why do not you spread it among your acquaintances, and why those politically active forestry experts do not raise these issues among their fellow politicians at the local, regional and even state level? We wonder, is it polite to say that you have "crawled into a mouse hole"? You answer it!
Editorial Board

Milan Pernek, Marta Kovač, Nikola Lacković  UDK 630* 453 (001)
Testing of biological effectiveness of pheromones and traps for catch of mediterranean bark beetle Orthotomicus erosus (Coleoptera, Curculionidae)      
In the Aleppo pine forests at the Croatian Mediterranean in 2017, a Mediterranean bark beetle (Orthotomicus erosus) appeared in population densities that had not been recorded before and until then was not considered a significant pest in that area. Natural enemies are not able to follow a sudden increase of the bark beetle population, which results in rapid increase of drying trees. As a part of the suppression of the Mediterranean bark beetle in 2018, pheromone traps have been installed in Croatia for monitoring purposes. Although there are multiple options for applying different types of traps and pheromone preparations for the Mediterranean bark beetle, so far the differences in catches of different types of traps and their selectivity have not been investigated. In 2019, 40 pheromone traps were placed in the Forest Park ​​Marjan (Split) on 196 ha of forest area. A pairs of pheromone preparations Pheroprax and Erosowit were compared, a system of three traps (Triplet) with a single flight barrier trap as well as the modified wet flight barrier trap with a regular flight barrier trap. In addition to the average number of catches in pheromone traps, particular attention was given to selectivity. Two predator species Tanasimus formicarius and Temnochila caerulea were found in traps, with T. formicarius in insignificant quantities relative to T. caerulea. The results indicate that Erosowit exhibits significantly higher catches compared to Pheroprax and is significantly more selective. Pheroprax has a very high catches of T. caerulea predators and is not recommended for practical use. The Triplet had only slightly better catches compared to the single flight barrier trap, but also showed slightly better selectivity. The Triplet did not show the expected effect due to the amount of the catch, which was slightly higher than in the single trap, but not significantly in order to recommend their use. The wet flight barrier trap turned out not to be satisfactory as it does not produce significantly higher catches than a regular flight barrier trap, and is twice less selective. Given the additional costs (trap adaptation, fluid that needs to be changed, slower collection), this trap type is not recommended for use. Comparing the results of the catch in 2019, the number of bark beetles was found to be almost 5 times lower than in 2018.

Key words: Pinus halepensis; Erosowit; Pheroprax; Taemnochila caerulea; Thanasimus formicarius; climate changes

    PERNEK, Milan      ŠL
    Marta Kovač  
    LACKOVIĆ, Nikola    ŠL
Mladen Ognjenović, Tom Levanič, Nenad Potočić, Damir Ugarković, Krunoslav Indir, Ivan Seletković  UDK 630* 425 + 111 (001)
Interrelations of various tree vitality indicators and their reaction to climatic conditions on a european beech (Fagus sylvatica L.) plot      
Interrelations of various common beech vitality indicators (crown defoliation, foliar chemistry, radial growth) as well as their possible dependencies on climatic conditions were investigated over the course of 12 years in a mature and healthy beech stand. Our results confirm the importance of temperature variables for defoliation, as high temperatures during spring and summer months induce the increase of defoliation. The same negative influence was observed with high maximum temperatures and low precipitation during previous year summer months. Phosphorus, calcium and magnesium nutrition of beech trees suffers from high temperatures during current year summer and benefits from more precipitation. High temperatures in current year May positively influence beech radial growth, while a wide range of minimum temperatures during March and June has a negative effect. In summary, high summer temperatures and low precipitation were shown to have a negative effect on all vitality indicators, and for defoliation and nutrition this effect can last into the following year.

Key words: defoliation; foliar nutrition; radial growth; drought; vitality

    Mladen Ognjenović  
    Tom Levanič  
    POTOČIĆ, Nenad      ŠL
    UGARKOVIĆ, Damir    ŠL
    INDIR, Krunoslav    ŠL
    SELETKOVIĆ, Ivan      ŠL
Simon Lendvai, Jurij Diaci, Dušan Roženbergar  UDK 630* 242 (001)
Response of black alder (Alnus glutinosa (L.) Gaertn.) to selective thinning of various intensities: a half-century study in northeastern Slovenia      
Pure black alder stands are specific and require adapted silvicultural models. To determine the best intensity of selective thinning in such stands, research plots were established in Polanski Log in 1967. Three thinning intensities were selected: control, moderate and high. These stands are presently in a mature phase. In 1967, 1973, 1979, 1983, 1993, 1998 and 2018 diameter at breast height was measured and social status, vitality, tendency, silvicultural role, crown length and overall quality were estimated. The differences in black alder responses to thinning intensities were analysed and the results were compared with recommendations for selective high thinning and newer crop tree situational thinning models. Diameter increments were lower than expected regardless of thinning intensity. In moderately thinned plots and control plots diameter increment was the same (0.33 cm/year); high intensity thinning plots showed higher increment (0.37 cm/year). Dominant trees had slightly higher increment regardless of thinning model. Compared to thinning models with a lower number of crop trees, density and basal area of studied stands were significantly higher and diameter increments lower. We attribute the small diameter increments and small differences among thinning models to insufficient intensity and partially to inconsistent thinning. The results indicate that thinning must be of higher intensity and the largest-diameter trees which display the best vigour, quality, tendency, and which have well formed, long crowns, must be promoted from the beginning.

Key words: black alder (Alnus glutinosa (L.) Gaertn.); thinning; diameter increment; traditional selection model; situational thinning model

    Simon Lendvai  
    Jurij Diaci  
    Dušan Roženbergar  
Besim Balić, Ante Seletković, Ahmet Lojo, Aida Ibrahimspahić, Jusuf Musić, Admir Avdagić, Velid Halilović  UDK 630* 516 (001)
Model for estimation merchantable wood volume of spruce (Picea abies Karst) in Canton 10, Federation of Bosnia and Herzegovina      
For assessment of growing stock in B&H forestry praxis as scientific baseline we are using volume tables and tariffs (Drinići dr. 1990). Having in mind the fact that these are constructed based on volume coefficients of the trees taken from German tree volume tables, which originate from single-age assortments, it is justified to suspect that by applying these tables one will get certain differences in quantity of large wood mass related to the actual status of those volumes. It is known that trees of the same tree species coming from single-age assortments are more full-bodied because they have larger volume coefficients compared to the trees of the same species from variable aged and selection forest assortments. That is why the objective of this research is to find “the best” regression model for levelling of volume of large wood of spruce, as dependent variable depending on diameter at breast height and tree height, as independent variables. To achieve this objective we have selected 377 model trees of spruce that were measured in felled condition on wider area of state owned variable aged assortments in Canton 10 (Livno Canton). To determine volume of large wood of trees we applied section method with sections of uneven absolute lengths (most often from 1 – 2 m). For levelling of volumes of large wood depending on diameter at breast height and tree height we applied method of multi-regression analysis. Quality of levelling and appropriateness of tested models was evaluated on the basis of determined values of basic statistical indicators for characterisation of the strength of correlation connections. The best values of the parameters showed model: V7=a0+a1d1,3+a2h+a3d1,3h+a4d1,32+a5 d1,32h with determined determination coefficient: R2 = 0,99 and size of standard regression error: Sey=0,245 m3. By testing significance of differences between actual/real tree volumes from the sample and volume of those trees determined by application of selected regression model by using t-test of pairs, no statistically significant differences were recorded. Average percentage of deviation was -0.44%. That means that in average we get 0.44% lower volumes comparing to the actual volumes in the sample of 377 spruce trees which shows that this regression model is usable for application in practice, because that average percentage is less than 1%. Statistically significant differences were recorded between volumes of trees of selected regression model and volume tables and models of other authors (Stojanović i dr. 1978; Banković i dr. 2003; Špiranec, 1976.). Those deviations vary in the range from 2.53% up to 22.7%. The largest deviations were determined exactly in model that is used in B&H (Stojanović i dr. 1978) and are in amount of 22.7% while the lower deviations were determined for volumes estimated by using model created for spruce trees from Sub-Alpine belt for area of Kopaonik (Banković i dr. 2003) and those amount to 2.53%.

Key words: spruce; merchantable wood volume; regression model; nonlinear regression; two-entry volume tables

    Besim Balić  
    SELETKOVIĆ, Ante      ŠL
    Ahmet Lojo  
    Aida Ibrahimspahić  
    Jusuf Musić  
    Admir Avdagić  
    Velid Halilović  
Hüseyin Ogfuz Çoban, Halis Bereket  UDK 630* 432 (001
Visibility analysis of fire lookout towers protecting the Mediterranean forest ecosystems in Turkey      
Urgent detection of fire and precise identification of its location are of critical importance for success of first response to fight forest fire. Forest fire lookout towers are main observation system and used in a sophisticated way to detect forest fires in Turkey. The objective of this study was to conduct visibility analysis of fire lookout towers deployed in mountainous Mediterranean forest region of Turkey, thereby assess their effectiveness. It is necessary to determine functionality and capacity of these towers to protect forest environment. Visible and invisible areas from towers were identified by using Geographic Information System and high resolution digital elevation data. In visibility analysis, scanning was performed with a rotation of 360 degrees at the 18 kilometres radius from the point where a lookout tower was located. Roads in this region are one of the elements that can be used in fire observation. People traveling on these roads may report forest fires by using cell phones. In this sense, the efficiency/effectiveness of the towers have been associated with forest road traffic. Therefore, visibility analysis of roads was also performed to check the observation capabilities from roads. Although there are 37 fire lookout towers in this area, where coniferous tree species such as brutian pine and black pine that are highly vulnerable to fire are dominantly distributed, 40% of forests are in parts that are not visible and 15% of them are at high risk of fire. More than 100 thousand hectares of fire-sensitive forest area in this region could not be controlled by the towers. The network of towers could view 56% of the overall area and 59% of the forest areas. People using the roads contributed to the lookout system by 11% and ensured that 70% of the forest area in this region was visible when combined with the towers. On the other hand, 59% of 523 thousand hectares of forest land that were not visible from the roads were visible from the towers. It was emphasized that the participatory behavior of people who lived in forests and used inner forest roads were an important part of the fire observation system. We recommend that the GIS-based methodologies including digital camera systems and remote sensing technologies in addition to the conventional lookout towers with a view to planning the economically, technically and operationally optimal fire lookout system.

Key words: viewshed analysis; fire risk; fire sensitivity; forest fire; forest road; Isparta

    Hüseyin Ogfuz Çoban  
    Halis Bereket  
Željko Španjol, Boris Dorbić, Nikola Vrh, Ivana Gašparović, Ivan Tolić, Milan Vojinović  UDK 630* 187 + 174
Vegetative and dendrological characteristics of Hober forest park in Korčula      
A systematic research of biological and ecological characteristics of the overall Hober area and Hober forest park itself has not been performed thus far. Structural characteristics of the stand were included only in The Management Plan for Hober Forest Park (2006-2015). Forestry issues were addressed in the paper by Vojinović (1997). Dendrological research was included in the papers by Denich and Draganović (1985), Vojinović (1997), Fabris (2001) and Onofri (2002). Its overall inventory records are missing.
The current condition of Hober forest park is characterised by its neglect and no landscape design in terms of both forest vegetation, dendrological, horticultural and garden and architectural content. Moreover, there is conceptual indefiniteness of the overall Hober area.
Hober forest park in terms of vegetation belongs to the forest community of the Aleppo pine and Holm oak (Querco ilicis – Pinetum halepensis Loisel 1971). It is primarily due to vegetative and structural unevenness that 7 experimental surfaces were placed in the forest park itself and 4 more outside of it. A comprehensive vegetation and structural analysis was intended for the selection of individual areas, in order to provide their description and present their condition, which can subsequently be used for the purpose of zoning the area.
According to the analysed research the Aleppo pine prevails in the layer of trees on the surfaces 1, 2, 3 and 9; Holm oak on the surfaces 4 and 5 and Common cypress on the surfaces 6 and 7. Laurestine is the most common species in the shrub layer, which appears on all the surfaces. Then there are green olive trees with broad leaves and mastic trees. The tree layer prevails with the exception of the surfaces 8, 10 and 11 where there is maquis. It is evident that in developed stands the tree layer and the shrub layer are almost equally dense. The latter is not the case on the surface 6, partially on the surface 9 and the surface 10 where maquis prevails and the surface 11, which is a natural succession of forest vegetation on abandoned agricultural surfaces. With the exception of maquis, there is a very high wood volume which, depending on stand development, ranges from 100 to even 270 m3/ha. The number of trees is also very large and it ranges from 1,000 to 2,700 per hectare. All this data indicates no landscape design and absence of any silvicultural work.
The objective of this paper is to explore vegetative, dendrological, silvicultural and structural characteristics of the overall Hober area. They are the primary indicators of the condition and will provide the guidelines for its future biological and spatial valorisation.

Key words: Hober forest park; vegetative characteristics; structural characteristics; dendroflora

    ŠPANJOL, Željko      ŠL
    Boris Dorbić  
    Nikola Vrh
    Ivana Gašparović  
    Ivan Tolić
    Milan Vojinović