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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   389
Will a change in the ministry bring about a changein the attitude towards the forestry profession?      
We have written on several occasions about how we expected the present Government to bring the word forestry back into the name of the line ministry and to change its attitude towards forests and the forestry profession. Regrettably, this has not happened, with the final result of the forestry sector within the Ministry being at the level of parts of agriculture, vegetable growing for example, although forests cover almost half of the land area of the Republic of Croatia. Needless to say, the forest is the most complex ecosystem in the world, whose management requires supreme expertise. The Constitution itself states that, along with soil and water, the forest is a resource of particular interest for the Republic of Croatia. We do not insist that the sector minister should be a renowned forestry expert, but the state secretary or assistant minister in charge of forestry should definitely be one. The Minister should take every opportunity to get to know the profession which is a constituent part of his Ministry. The best way to do it is to attend at least several professional symposia in which the status and problems of the profession are discussed on a scientific-professional basis. We regret to say that the deposed department minister did not attend one single gathering, not even the one organized by the Croatian Academy of Sciences and Arts. This we regard as both the belittling of the profession and of the mentioned scientific institution. The only visible trace that he left in forestry was the establishment of “his” Forestry Administration at the expense of reducing the area of the adjacent Administrations. At present, the forestry department is headed by a wood technologist, which is illogical, but even worse, the forestry profession seems to approve of this. Who runs the forestry policy and do we have a good strategy for running it? Who is the forestry policy subjugated to? There is a general impression that the forestry policy is led by wood processors, and what is tragic, by wood processors in primary wood processing, who are guided by non-market conditions and who disregard the principles of sustainable management.
At the scientific-professional gathering held to mark the Days of Croatian Forestry, Oliver Vlainić, President of the Croatian Forestry Association, mentioned current problems in forestry and attitudes of the profession. We have nothing more to add to this but to ask the readers to read the reviews of the gathering in the past double issue of the journal. Clearly, the profession repeatedly warns of the alarming conditions in forestry which the competent ministry obviously does not recognize.
Considerable financial means will be required to repair the damage caused by ice and wind storms in Gorski Kotar and to remedy the situation with disastrous ash dieback and the oncoming problems with oak, the most valuable tree species in Croatia. Where to find these means if, according to the new Forest Act, the financial means from non-market forest functions fees have been significantly reduced while wood assortments continue to be sold at non-market conditions? We did not have to wait long to see how the new lady minister will treat forests and forestry by her Decision to lower the fees for forests and forest land. The value of the points was reduced by 30 to 90%, depending on the silvicultural form of the forest. To quote her words, this will accelerate investment projects, because, allegedly, many investments in which it was necessary to exclude forests or forest land from forest management plans, were called into question due to excessive fees for local or regional self-managing units. Of course, they are “not crazy” to pay to private owners, who have hundreds of thousands of hectares of abandoned and overgrown land, when the state (read: public) land is almost free of charge. For them a scrub, a thicket, maquis, and garrigue is not much of a forest anyway. The latest is the announcement of a new reduction in the non-market forest function fee by “increasing the level of total annual income from 3 000 000.00 kuna to 7 500 000.00 kuna, which was explained by a burden, both on the entrepreneurs and the administrative processing”. Due to reduced means from non-market forest functions, which are currently mainly used for demining and for the fire fighter service, very little is left for “green” operations on about one million hectares of karst. What is there left to say?
Let us talk a little bit about climate change, oxygen, carbon dioxide, erosion, potable water, recreation and environment protection in general, where the forest is one of the most important and most complex ecosystems, and about which everybody, although lacking professional education, knows everything because they all love forests.
We often mention the principle of sustainability and the insurance of the multipurpose role of a forest, which is the motto of business-making in forestry. However, the first step is to change the general belief that the forest can be used without investing into it or without returning to it a part of the benefits. Only if we do so will forests remain an eternal asset.
<br>Editorial Board

Damir Ugarković, Željko Španjol, Ivica Tikvić, Dražen Kapučija, Ivana Plišo Vusić  UDK 630* 111 (001)
Microclimate differences in the degradation stages of holm oak (Quercus ilex L.) forests      
Maquis and garrigue are the most common degradation stages of Holm oak forests in Croatia. Disorganized and uncontrolled cutting degrades forests and changes their microclimates. Measurements were conducted in a Holm oak forest in the maquis and garrigue degradation stages, and in an Aleppo pine forest with Holm oak. The highest variations of microclimate elements were measured in the degradation stages of Holm oak. The average air and soil temperatures, precipitation, and potential evapotranspiration were highest in the garrigue stage and lowest in the maquis stage. The average volumetric soil water content was highest in the maquis stage (14.28%) and lowest in the garrigue stage (9.46%). The dry season water deficit was highest in the garrigue stage (-73.95 mm) and lowest in the maquis (-60.38 mm). Microclimate conditions in the garrigue degradation stage are less favorable for the growth and development of Holm oak than in high forest stands. The average values of microclimate elements in the Aleppo pine forest stand with Holm oak were within the average range of the microclimate elements of garrigue and maquis.

Key words: Forest microclimate; forest structure; Holm oak; degradation stages; Aleppo pine

    UGARKOVIĆ, Damir    ŠL
    ŠPANJOL, Željko      ŠL
    TIKVIĆ, Ivica      ŠL
    Dražen Kapučija  
    Ivana Plišo Vusić  
Ivan Lukić, Nikola Lacković, Milan Pernek, Christa Schafellner  UDK 630* 453 (001)
Redefinition of critical numbers of gypsy moth (Lymantria dispar L.) egg masses for pedunculate oak (Quercus robur L.) and first calculation for common beech (Fagus sylvatica L.) in Republic of Croatia      
The gypsy moth (Lymantria dispar) is one of the most important forest pests in Croatia and a primary biotic factor responsible for oak decline, especially when tree defoliation during mass outbreaks is followed by infections with the oak powdery mildew (Erysiphe alphitoides). Population dynamics of gypsy moth differs between the two main regions of Croatia. In the Continental part, outbreaks occur in cycles every 10 to 11 years, the last one was recorded from 2012 – 2014. In the Mediterranean part, outbreaks are more frequent and less synchronized between sites. Key elements for sustainable forest management are forest pest monitoring programs and the assessment of pest population densities in time and space. In the case of gypsy moth, this is especially true since protection measures should be applied properly and only when prognoses of outbreaks predict severe negative impacts on the forest stands. Gypsy moth population density assessment in Croatia is carried out by counting the egg masses along transects in the forest stand. Predictions of infestation levels, through the number of gypsy moth egg masses per tree or hectare, uses five classes. Calculations include the number of trees with at least one egg mass, expressed in percentage of total. In the case of defoliators like gypsy moth, the basis for the prediction of defoliation is the average leaf mass consumed per one larvae. According to Androić (1965) a single larva consumes 12 g leaf material, however, detailed descriptions of the experimental setup and the tree species used for the feeding trials are missing.
The aims of this paper were to (1) redefine the critical numbers of gypsy moth egg masses used so far for pedunculate oak (Quercus robur) and (2) define critical numbers for common beech (Fagus sylvatica).
Egg masses for the laboratory experiments were collected in the continental region (forest area near city of Koprivnica) in December 2015. First, larvae were fed in groups from hatching to the end of the third instar with pedunculate oak or common beech leaves. Newly emerged fourth instars were then separated and kept individually. Larvae were weighed daily from the start of the fourth instar until the prepupal stage. Mass of pupae were determined three days after pupation. Fresh leaves used for feeding were weighed daily, the unconsumed leaf remains were collected, dried and also weighed. The leaf material was changed weekly. The fresh/dry mass ratio were calculated for each week to assess the dry mass of freshly given leaves. The average dry leaf mass consumed per larva was used to calculate the critical numbers of gypsy moth egg masses per tree and stand. The average leaf mass per one tree was calculated from biomass models on a dry mass basis.
The recalculated critical numbers of gypsy moth egg masses for pedunculate oak are higher in comparison with the ones used until recently. Data relating to critical numbers of gypsy moth egg masses for common beech represent new findings for Croatia. Until recently, all defoliation predictions in common beech stands were based on data used for pedunculate oak. The higher critical numbers of gypsy moth egg masses is confirmed for the management units Ključevi (pedunculate oak) and Petrinjčica (common beech).
In this study we also redefined the the average leaf mass consumed per one larvae. New critical numbers of egg masses still require field validation during the next gypsy moth outbreak. Future research about critical numbers of gypsy moth egg masses could implement data from yield tables (site quality and ecological and economic types (EGT)) and data from the national forest inventory. Usage of currently available biomass models points out the need for further studies about average leaf mass per one tree in Croatia (Table 5 and 6), in order to calculate critical numbers of gypsy moth egg masses more precisely.

Key words: forest pest; population density; egg masses; larvae

    LUKIĆ, Ivan    ŠL
    Nikola Lacković  
    PERNEK, Milan      ŠL
    Christa Schafellner  
Muammer Şenyurt, Ilker Ercanli  UDK 630* 524 (001)
A comparison of artificial neural network models and regression models to predict tree volumes for crimean black pine trees in Cankiri forests      
In this study, it is aimed to use and compare Artificial Neural Network (ANN) models for predicting individual tree volumes for of Crimean Black Pine trees within the Cankiri Forests. The single and double entry-volume equations and the Fang et al. (2000)’s compatible volume equation based on the classical and traditional methods were used by 360 Crimean Black Pine trees to obtain these tree volume predictions. To determine the best predictive alternative for ANN models, a total of 320 trained networks in the Multilayer Perceptron (MLP) and a total of 20 trained networks in the Radial Basis Function (RBF) architectures was trained and used to obtain the individual tree volume predictions. On the basis of the goodness-of-fit statistics, the ANN-based on MLP 1-9-1 including dbh as an input variable for single entry volume predictions showed a better fitting ability with SSE (2.7763), (0.9339), MSE (0.00910), RMSE (0.0954), AIC (-823.25) and SBC (-1421.81) than that by the other studied volume methods including dbh as an explanatory variable. For double entry volume predictions, including dbh and total height as input variables, ANN based on MLP 2-15-1 resulted in better fitting statistics with SSE (0.8354), (0.9801), MSE (0.00274), RMSE (0.0523), AIC (–579.55) and SBC (–1788.11).

Key words: Tree Volume Prediction; Artificial Neural Network; Single and double volume equations; Segmented taper equation

    Muammer Şenyurt  
    Ilker Ercanli  
Tomislav Sedlar, Tomislav Sinković, Ivana Perić, Andrej Jarc, Srđan Stojnić, Bogoslav Šefc  UDK 630* 812 (001)
Hardness of thermally modified beech wood and hornbeam wood      
There is increasing number of products made of termally modified wood (mainly floor coverings) in wood market. Thermal modification at temperatures above 160 °C in oxygen free environment is known to alter the physical and mechanical properties of wood, among others. In this work, change in Brinell hardness of beech wood and hornbeam wood subjected to 200 °C in oxygen free environment for 48 hours was investigated in relation with unmodified wood of the same species. Beech and hornbeam were selected because of the impacts of climate change as well as future predictions on the distribution of beech and hornbeam in South East Europe. Wood hardness was investigated on cross, radial and tangential sections. The dependence of wood hardness on wood density was also shown. All measurements were performed at 12% EMC (equilibrium moisture content) of wood. The average values of Brinell hardness of termally modified beech wood and hornbeam wood were significantly different and smaller than the average values of unmodified beech wood and hornbeam wood. As expected, thermal modification caused weight reduction and consequently, decrease in the density of beech wood and hornbeam wood. Applied thermal modification reduced Brinell hardness of beech wood cross section for 3%, radial section for 15%, and tangential section for 25%. Applied thermal modification reduced Brinell hardness of hornbeam wood cross section for 6%, radial section for 18%, and tangential section for 13%.
Applied thermal modification negatively influenced Brinell hardness on all three sections of investigated beech wood and hornbeam wood. The recorded decrease in hardness still does not hinder the use of such modified wood in non-load-bearing wood structures and wood flooring.

Key words: Brinell hardness; thermally modified wood; beech wood; hornbeam wood

    Tomislav Sedlar  
    SINKOVIĆ, Tomislav    ŠL
    Ivana Perić  
    Andrej Jarc  
    Srđan Stojnić  
    ŠEFC, Bogoslav    ŠL
Anamarija Jazbec, Mislav Vedriš, Ksenija Šegotić  UDK 630*945
Analysing the duration of studyng on undergraduate studies et the Faculty of forestry, University of Zagreb      
Although forestry is often considered as a traditional field of applied science, it resumes its importance in context of increased awareness of climate change and benefits coming from natural ecosystems. Updated and contemporary study programmes are needed to ensure an adequate education on managing forest ecosystems and its products.
A better insight in student background and their motivation for studies are welcome to improve the study programmes and also to find the ways how to help students achieve better results. A case study research was carried out to measure success of studies by duration of studies and average grades achieved, with possible causes. Three undergraduate study programmes on Zagreb Faculty of Forestry were analyzed (Forestry N=94, Urban forestry N=54 and Wood Technology N=39), with data acquired from a questionnaire among forestry graduate students on the same faculty academic year 2016/2017. A Factorial ANOVA was performed to test differences between the studies, and a multivariate linear regression for the influence of predictor variables on the duration of study.
Although this profession is associated with people from rural areas, about one third of all students comes from the capital city (Figure 1). Students of Wood Technology (DT) are mostly coming from vocational schools (70%) while Forestry (ŠO) and Urban Forestry (UŠ) students are mostly from gymnasiums (67% and 83%). For about 91% of students main motivation was a personal sake rather than a family interest (9%). Average scores and the duration of study on three study programmes have not been proven significantly different between the studies, nor between male and female students (Table 5). A longer time of study is proven to negatively correlated with the average grades on all study programmes: ŠO (r = -0,56), UŠ (r = -0,55) and DT (r = -0,38) (Table 4.). Statistically significant predictor for duration (with logarithmic transformation) on all study programmes in regression analysis was the average grade, with negative sign, thus leading to a shorter study time. Additional statistically significant predictors for ŠO were obtained grant and personal motivation (negative sign), and for DT were sex, obtained grant, and type of high school (Table 6).

Key words: academic performance; average grade; duration of study; regression analysis; study programme

    Anamarija Jazbec  
    VEDRIŠ, Mislav      ŠL
    Ksenija Šegotić  
Jelena Nedeljković, Mirjana Stanišić, Dragan Nonić, Mersudin Avdibegović, Marta Curman, Špela Pezdevšek Malovrh  UDK 630* 111
Climate change governance in forestry and nature conservation: institutional framework in selected see countries      
Global environmental and ecological problems such as climate change and other related issues (e.g. biodiversity losses) do not recognize state boundaries. Therefore, intentions to address these problems require a multi-actor, multi-sector and multilevel approach. The concept that enables joint effort against these problems implies an active participation of all stakeholders, establishes the rules for shared responsibilities and strives to make efficient and effective procedures for addressing these issues is known as “governance” (Mutabdžija, 2012).
Climate change and occurance of extreme events are presenting a threat to the natural resources, exposing the vulnerabilities of current resource governance regimes, including also forestry and nature conservation. The occurance of extreme events in last several years thretened the natural resources and impacted the forestry sector in all four selected countries of Southeast Europe (Bosnia and Herzegovina, Croatia, Serbia, and Slovenia). This has provided a further arguments for understanding the institutional framework for climate change governance in forestry and nature conservation as important element in dealing with uncertanties posed by the climate change challenges on natural resources.
Hence, the aim of the paper is to examine the institutional frameworks of forestry and nature conservation, as well as the attitudes of respondents about the competences of the relevant institutions and organizations, to identify the need to improve the existing framework and to evaluate their interests and impacts in climate change governance.
In this research were used individual, structured interviews as a research technique in collecting the primary data. The questionnaire consisted of 22 questions, divided into 5 groups. For the purposes of this paper, responses to questions related to institutional frameworks for climate change governance in forestry and nature conservation are analyzed. The sample consisted of 29 representatives (Federation of Bosnia and Herzegovina – 8, Croatia – 6, Serbia – 10, Slovenia – 5) from public administrations and services in forestry and nature conservation, enterprises and organization for forest and protected area management, educational and research organizations, and non-governmental organizations. The respondents were selected by judgemental sampling.
Current institutional framework for climate change governance comprises of various institutions and organizations in all analyzed countries (Table 1). In selected countries, there is a clear division of responsibilities between public administration institutions in forestry and nature conservation (these institutions are directly or indirectly are related to forestry). There is a number of common primary objectives within the given competencies common to the same organizational category (Table 2), in all four countries. Despite current institutional and organizational variaty and competency alignment between different institutions and organizations, there is a need for further improvement of institutional framework for climate change governance through cooperation and coordination, accross different sectors, institutions and organizations, as stated by the respondents attittudes (Table 3 and 4). Respondents attitudes towards the interest and influence of institutions/organizations on climate change governance are mostly showing a visible interest but indicating challenges in providing suitable inflluence (Table 5). Also, visible discrepancy in assessment of the interest and influence of institutions and organizations on climate change governance is between the respondents from Slovenia and Croatia at one side and respondents from Federation of Bosnia and Herzegovina and Serbia at the other side, indicates differences in inclusion of climate change challenges accross different competency levels. Regardless of the category of institutions and organizations, the respondents recognized the importance of the investigated issues and they assessed its interest as “high” and “very high” (Table 6).
Further development of suitable institutional frameworks for climate change governance in forestry and nature conservation needs additional attention especially in the field of multilevel coordination between different actors and their activities, as well as the acknowledgment of potentially significant influence forestry sector might have in climate change governance.

Key words: institutional framework; climate change governance; forestry; nature conservation; Southeast Europe

    Jelena Nedeljković  
    Mirjana Stanišić  
    Dragan Nonić  
    Mersudin Avdibegović  
    Marta Curman  
    Špela Pezdevšek Malovrh  
Ivana Plišo Vusić, Irena Šapić, Joso Vukelić  UDK 630* 181.6 + 187
Identification and mapping of Natura 2000 forest habitat types in Croatia (II) – 91F0, riparian mixed forests of Quercus robur, Ulmus laevis, Ulmus minor and Fraxinus angustifolia; 91L0, Oak-hornbeam forests of the illyrian area      
The article describes the 91F0 and 91L0 Natura 2000 habitat types in Croatia. It containes 11 types according to the National Habitat Classification of Croatia (NHC).
The 91E0 habitat type extends to northern Croatia, in the river valleys of Sava and Drava, to approximately 100,000 ha. It consists of forests dominated by Quercus robur in admixture with Fraxinus angustifolia, Alnus glutinosa and Ulmus minor. Carpinus betulus and mesophilic species are absent. The habitat is wet, with a high level of groundwater. Floods are periodic and do not last long.
According to the NHC, type 91F0 includes phytocenoses:
                E.2.2.1. Genisto elatae-Quercetum roboris caricetosum remotae Horvat 1938
                E.2.2.2. Genisto elatae-Quercetum roboris caricetosum brizoides Horvat 1938
                E.2.2.3. Genisto elatae-Quercetum roboris aceretosum tatarici Rauš 1975
                E.2.2.4. Genisto elatae-Quercetum roboris carpinetosum betuli Glavač 1961
Habitat type 91L0 comprises of two groups of syntaxons: pedunculate oak and hornbeam communities and sessile oak and and hornbeam communities. Pedunculate oak and hornbeam forests grow on the highest parts of the lowlands of Croatia. The ground is fresh, the groundwater level is lower than in the 91F0 type, and in floral composition there is a significant share of Central European mesophilic species.
Sessile oak and hornbeam communities grow in hilly belt of continental Croatia, predominantly in brown forest soils of neutrophil character. The main tree species are Quercus petraea, Carpinus betulus, Acer campestre, Prunus avium and Fagus sylvatica. Within the shrub and herb layer the Illyrian floral element is significant, with species Lonicera caprifolium, Staphylea pinnata, Epimedium alpinum, Erythronium dens-canis, Helleborus atrorubens, Vicia oroboides and others.
According to the NHC, type 91L0 includes phytocenoses:
Pedunculate oak and hornbeam communities (Carpinion betuli)
                E.3.1.1. Carpino betuli-Quercetum roboris typicum Rauš 1975
                E.3.1.2. Carpino betuli-Quercetum roboris fagetosum Rauš 1975
                E.3.1.3. Carpino betuli-Quercetum roboris quercetosum cerris Rauš 1971
                E.3.1.4. Carpino betuli-Quercetum roboris tilietosum tomentosae Rauš 1971
Sessile oak and and hornbeam communities (Erythronio-Carpinion)
                E.3.1.5. Epimedio-Carpinetum betuli /Ht. 1938/ Borhidi 1963)
                E.3.1.6. Festuco drymeiae-Carpinetum Vukelić ex Marinček 1994)
                E.3.1.7. Anemone nemorosae-Carpinetum Trinajstić 1964
This article contains a description, area of distribution in Croatia, and diagnostic indicators for each habitat type. For each type related types are listed, the corresponding code according to EUNIS-classification, and literature in which is described in more detail. The article is intended for forestry experts, for identification and mapping of forest habitat types.

Key words: 91F0 and 91L0 Natura 2000 habitat types; oak forests; National habitat classification; Croatia

    Ivana Plišo Vusić  
    Irena Šapić  
    VUKELIĆ, Joso      ŠL
Damir Drvodelić, Igor Poljak, Ivan Perković, Mario Šango, Katarina Tumpa, Ivana Zegnal, Marilena Idžojtić  UDK 630* 232.3
Laboratory germination testing of the sweet chestnut (Castanea sativa Mill.) according to ISTA rules      
The paper presents the results of laboratory germination testing and morphological characteristics of sweet chestnut (Castanea sativa Mill.) seedlings. The research samples were collected in the sub-Mediterranean region of Croatia, and the working sample for germination testing was 8×25 seeds. Prior to germination testing, the seeds were stored in a refrigerator for three months at 3°C. The percentage of laboratory germination was established according to the percentage of regular seedlings which germinated normally after 27 days of testing. The testing was carried out in a laboratory under the conditions prescribed by ISTA (International Seed Testing Association). A digital photo camera was used to take photos of all abnormal seedlings, which were then catalogued with their pictures and descriptions. The results of this research are very useful for nursery practice and can be applied in producing plants from seeds, rootstocks for grafting, and further raising of seedlings to be grown in plantations.

Key words: sweet chestnut; seedling morphology; normal seedling; abnormal seedling; germination; forest nursery

    DRVODELIĆ, Damir      ŠL
    Igor Poljak  
    PERKOVIĆ, Ivan      ŠL
    ŠANGO, Mario    ŠL
    Katarina Tumpa  
    Ivana Zegnal  
    IDŽOJTIĆ, Marilena      ŠL