|At the end of 2023
The end of the year is usually the time to make an account of what has been done in the course of 12 months. We shall make a brief review of the topics dealt with in the Editorials. The volume 1-2/2023 was devoted to the lease of forest land – a relatively topical issue in the past several years. In order to enlarge the area intended for this purpose several changes and amendments were made to the former Forest Planning Regulation, and this year to the Forest Act. Facilitating and helping livestock farming created problems for forestry and other users of the area, which will need to be rectified in the future. The Editorial 3-4/2023 was devoted to March 21st, the International Day of Forests. Forests are becoming increasingly more important not only as a natural resource but also as a source of other values. This year’s theme of the International Day of Forests was Forests and Health, or Healthy Forests for Healthy People, with special focus on the health function of forests. However, the health of forests in the world and in Croatia is faced with challenges which will have to be addressed by Croatian forestry experts. The Editorial 5-6/2023 was devoted to the Faculty of Forestry and Wood Technology in Zagreb as the provider of education in the forestry and wood technology profession. Established in 1898 as the Forestry Academy, through 125 years of activity it has developed into a modern higher education institution ready to adapt to the needs of the times. This year’s short-lived July storm will be remembered as an unprecedented disaster for forests, particularly for the most valuable stands of the Spačva basin, which was dealt with in the issue 7-8/2023. The initial estimate on forest damage was 1.5 million m2 of growing stock, but it amounted to 3.5 million m2 by the end of the year. The consequences of the storm will be felt for years and regeneration of the affected stands will face enormous difficulties. The issue 9-10 was concerned with whether we should worry about the future of human resources in forestry. The attractiveness of education and employment in forestry in Croatia, along with negative demographic trends, is increasingly declining. In addition to the aforementioned problems concerning the health of Croatian forests, the future of work in these forests does not offer too much optimism.
The purpose of our editorials is not to find difficult topics in forestry but primarily to initiate changes for the better for all stakeholders of the sector, society and the state by providing reviews and opinions. Let us mark the 147th year of the publication of Forestry Journal on a brighter note. In three years, we will celebrate the impressive 150 years of uninterrupted publication of the scientific-professional and specialized journal of the Croatian Forestry Association, which ranks it among the 10 oldest forestry journals in the world. Merry Christmas, Happy New Year 2024 and lots of health, personal and business successes to all CFA members and their loved ones and to all readers of Forestry Journal! May you yourselves participate in the creation of new anniversaries with your contributions!
|IZVORNI ZNANSTVENI ČLANCI
|Damir Drvodelić, Milan Oršanić, Damir Ugarković, Mario Šango
| UDK 630* 232.3 (001)
|Comparison of vitality and laboratory germination of holm oak acorns (Quercus ilex L.)
Holm oak forests in Croatia are in various stages of degradation, and one of them is maquis, which is a less favorable stage for the germination of holm oak seeds compared to holm oak stumps or stands of high growth form. Holm oak is a xerophytic species of forest trees. From the geological base, it comes from limestone, which is the most common in our Mediterranean area, and dolomite. Begins to flower in the eighth year of life, and the seed harvest begins at the age of 12 to 15 years, and the full harvest is every 4 to 6 years. The holm oak acorn crop is variable, where three abundant acorn crops were recorded in the eight-year period. The full harvest of holm oak depends on climatic conditions, but it also differs significantly between different habitats, especially the geological base and soil type. For laboratory analyses, holm oak acorns were collected in the area of G.J. “Kamenjak” on the island of Rab. The aforementioned G.J. managed by “Hrvatske šume d.o.o.” The seeds were collected in department unit 15a, 16a, 26a and 27a in the period from 01/12/2020 to 10/01/2021. The collection was carried out using the method of shaking acorns from the trees onto mats placed under the canopy and the method of collecting fallen acorns from the ground. Assessment of seed vitality using the tetrazole method and laboratory germination was made according to the ISTA rules for holm oak. The percentage of laboratory germination was determined according to the percentage of normal seedlings that germinated normally after the 35th day of testing. The total vitality of holm oak acorns was high and amounted to 90.25 %, while the rest of 9.75 % consisted of non-vital seeds. Of the vital seeds, the largest percentage (79.50 %) consists of seeds with fully colored embryo and cotyledons. Acorns with cotyledons that has necrosis up to 1/3 on the distal part and are not connected to the embryonic cavity
was 10.75 %. In the first seven days, not a single acorn germinated, so the germination energy was 0.00 %. In the first 14 days, laboratory germination was 30.50 %, after the 21st day 76.50 %, after the 28th day 83.75 % and after the 35th day 88.50 %. The difference between the assessment of acorn vitality and total laboratory germination was only 1.75 %. The vitality assessment method is faster and cheaper than the germination test. We get the results of the vitality assessment in 18 hours, while we test the germination after 28 or 35 days. Practical procedures can be based on the results of these studies suggest testing the vitality of the holm oak and not the laboratory germination as recommended by the ISTA rules. The average germination time (MGT) was 19.91 days. There were 74.25 % of regular seedlings and 14.25 % of irregular ones. At the end of the test, 8.50 % of the visually healthy acorns did not germinate, while 3.00 % of the rotten acorns were found. The most common irregularity in the amount of 56.14 % was determined for the category of two joined seedlings, followed by necrosis of primary leaves (12.28 %) and stunted primary root (10.53 %). Other irregularities appear in less than 10,00 % of cases.
Key words: island of Rab; tetrazole method; ISTA rules; normal seedlings; abnormal seedlings
DRVODELIĆ, Damir ŠL
ORŠANIĆ, Milan ŠL
UGARKOVIĆ, Damir ŠL
ŠANGO, Mario ŠL
|Nera Bakšić, Darko Bakšić
| UDK 630* 114 (001)
|Forest floor fuel loads in holm oak (Quercus ilex L.) and pubescent oak (Quercus pubescens Willd.) forests
The application of newer remote sensing methods, such as aerial and terrestrial lidar scanning and the use of "Structure-from-motion" (SfM) photogrammetry, complemented field data collection and enabled 3D mapping of forest fuel layers, greatly simplifying and improving their characterization. However, these methods are not suitable for quantifying forest floor characteristics. For this purpose, it is still necessary to collect data using classical field methods, determining the presence of subhorizons and their depth, while the characteristics of the forest floor: bulk density, load, carbon concentration and carbon stock are determined in the laboratory.
Therefore, it is still common practice to create regression equations that allow operatives to determine the amount of available forest floor fuel and the carbon stock it contains based on the depth of the forest floor, which is an easily measurable variable, or to determine forest floor loading by subhorizon and overall. Forest floor information is used in models for predicting forest fire behavior and spread, in fire effects models, in planning and monitoring mechanical fuel reduction, in quantifying fuel consumption and smoke emissions, in quantifying carbon stocks, in describing habitat and its productivity, and in planning for preparedness. As stands of holm oak (Quercus ilex L.) and pubescent oak (Quercus pubescens Willd.) are located in the Mediterranean part of Croatia, where the risk of forest fires is the highest, and the previously published data on the forest floor are not suitable for the models, the main objectives of the research were to determine the depth, bulk density and load of individual subhorizons of the forest floor and to create regression equations that allow estimating the amount of available fuel in the
forest floor based on its depth. Sampling of forest floor in holm oak stands (60, 90 and 100 years old) was conducted on the islands of Lastovo and Mljet, while sampling in pubescent oak stands (53 and 90 years old) was conducted in Dugopolje and Biograd na Moru. The amount of forest floor and OC stock in old stands of holm oak and pubescent oak is twice as small as in old stands of Aleppo pine and Dalmatian black pine. This suggests that pine stands have a significantly greater amount of potentially available fuel in the forest floor and are therefore potentially more at risk from fire, but also that they store twice as much carbon in the forest floor. In this study, for the first time in Croatia, bulk densities of individual subhorizons of the forest floor were determined for holm oak and pubescent oak and regression equations were created that allow estimating the amount of available fuel in the forest floor based on its depth per subhorizon and overall. The results of this research have practical value in simpler quantification of forest floor fuel loading, which is important for operational use of models to predict forest fire behavior and spread, but they can also be used in other models mentioned earlier.
Key words: holm oak; pubescent oak; forest floor; forest floor fuel loads; carbon stocks
BAKŠIĆ, Nera ŠL
BAKŠIĆ, Darko ŠL
|Mirzeta Memišević Hodžić, Sulejman Sinanović, Dalibor Ballian
| UDK 630*164 (001)
|The relationship of growth characteristics and wood quality on the experimental plot of larch
Larch (Larix decidua) showed good growth and adaptability to ecological conditions in Bosnia and Herzegovina. The research aims to determine the variability of the morphological traits of larch in the seed stand near Kakanj, the variability at the beginning of heartwood formation, and correlations among these properties.
In the larch seed stand, established by seedlings 2+0 in 1979, an area of 0,45 hectares was set aside. The heights and breast height diameters of the trees were on that area were measured in 2002 and 2020, and the basal area and volume were calculated. In 2020, the trees were drilled at breast height with a Presler drill to measure the proportion of heartwood. Average values of all properties for 2002 and 2020 were calculated. The ten, five and one best trees were selected according to the properties of breast height diameter, height, basal area, volume, and the intensities of selection for these traits were calculated. The Pearson correlation coefficient among all investigated traits were calculated.
The average breast height diameter of 41-year-old trees was 24,6 cm, average height 21,8 m, basal area 0.0499m2 and volume 0.3745 m3 (table 1), while in 2002. the average breast height diameter was 15,5 cm, height 18,2 m, basal area 0,020 m2, and volume 0,128 m3 (table 1). Between 2002 and 2020, there was an overtaking of trees in breast height diameter and height and thus the base and volume (table 2). The average larch tree starts heartwood formation at the age of 14 years (table 1). The earliest heartwood formation occurs in the sixth year (tree 495) and the latest in the 32nd year (table 4). Pearson coefficient showed a high positive correlation between breast height diameter and height in 2002 (table 9), which means that trees with a good height increase also have a good thickness increase. As a result, the correlation between breast height diameter and basal area and breast height diameter and volume, height and basal area, height and volume, and basal area and volume are statistically significant. Pearson’s correlation coefficient for the year 2020 showed a negative correlation between the beginning of heartwood formation and all other traits (table 10), i.e., trees that formed heartwood earlier have higher values of growth traits.
The results will be used in the selection processes of larch individuals with good height and thickness growth and early heartwood formation.
Key words: European larch; morphological properties; core formation; selection
Mirzeta Memišević Hodžić
|Biljana M. Nikolić, Katarina Mladenović, Ljubinko Rakonjac, Slobodan Milanović, Marija M. Marković, Srdjan Bojović, Nevena Čule
| UDK 630*164+272 (001)
|Influence of crown exposure on the morphological needle traits of nine conifers
The aim of this research was to investigate if the crown exposure of some conifers influenced to needle properties. The leaf morphological traits of sixty-six trees of nine conifers: Atlas cedar, Austrian pine, Blue spruce, Douglas fir, European spruce, European yew, Serbian spruce, Silver fir, and White fir, from six Belgrade parks, were analyzed. Five needles were measured from each of the four main crown exposures. Length, width, area and perimeter of needles were investigated. Species, parks in which they were found, as well as crown exposures, differed mostly in needle length and needle width. Correlations between measured needle traits were determined by linear regression analysis. Strong positive correlations were found between the length, perimeter, and area of needles. The differences among the species in terms of light requirement determine species for individual planting as light-loving or partial shade species (Atlas cedar, European spruce, Serbian spruce, Blue spruce, Austrian pine and Douglas fir), or for group planting as shade-loving species (Silver fir, White fir and European yew).
Key words: conifers; correlations; exposure; needle morphology; parks
Biljana M. Nikolić
Marija M. Marković
|Jovana Devetaković, Milutin Đilas, Ivona Kerkez Janković
| UDK 630*164
|Stocktype impact on survival and growth of one-year old Quercus pubescens seedlings on the edge of Panonnian basin
Querqus pubescens has relatively wide distribution in Europe, but dominated forests are quite common in South Europe, while they are confined to warm microclimatic conditions in central Europe. On the edge of the Panonnian basin Q. pubescens is mainly found on the edge of its native range, in isolated populations which have an important role in examining the adaptive potential, especially considering that the forest-steppe and sub-mediterranean climate is predicted to be the dominant climate in some regions of Central Europe in future. There are very limit knowledge about Q. pubescens forest establishment and restoration in continental climate today. This study provides information about stocktype effect on seedlings success after outplanting in very competitive conditions. Although bareroot seedlings were larger in the nursery, container seedlings had better survival and growth on the field. Generally, low survival rate for both stocktypes (mean survival 47.60 %; container seedlings 55.41%; bareroot seedlings 41.41%) can be assessed as consequence of uncompetitive seedlings and lack of vegetation control.
Key words: stocktype; survival; growth; lack of vegetation control; restoration
Ivona Kerkez Janković
|Martina Đodan, Robert Bogdanić, Marija Gradečki-Poštenjak, Sanja Perić
| UDK 630*232.3
|Production of broadleaves forest planting material in the Republic of Croatia from 2017 to 2021
Analysis of nursery production contributes to better planning of production and silvicultural activities. Availability of planting material is crucial for many actors in forestry science and practice. According to Law on forest reproductive material Croatian Forest Research Institute conducts expert supervision and collects data on production programme and process for every nursery in Croatia (Figure 1). This enabled statistical analysis of total amounts of planting material production per nursery, ownership and tree species in recent five-year period. Comprehensive ovierviews and analysis of nursery production are limited for the last three decades, while there is also a lack o recent scientific publications and activities dealing with nursery production issues in Croatia. Aims of this paper are: (1) to give a production overview according to tree species, ownership and nursery, (II) to determine if amount and production programme is harmonised with growing needs of practical forestry and recent international scientific knowledge, (III) to give general guideliness for planning of production programmes for broadleaves in Croatia. Nursery production data used for production analysis is part of electronic database, which was established (based on expert supervision documentation) in period 2009-2011 by Đodan and Perić. Croatian Forests Ltd. are single producer of forest planting material in Croatia. Figure 2 gives overview of the size of nurseries in Croatia. Production of broadleaves planting material in respected period drops, while more detailed insight of production per nursery points to Cernik, Limbuš, Oštarije, Zdenački gaj and Višnjevac as the biggest producer in Croatia (Figure 3). Total broadeleaves production in five year period spannes from 12.373.091 pcs. (2021) to 21.654.920 pcs. (2019) (Table 1), with slight drop. Total production of Quercus spp. in respected period amounts to 62.245.950 pcs., while pedunculate and sessile oak participate in total oak production with 98,49% share. Other oaks in production are Quercus pubescens Willd., Quercus cerris L. and Quercus ilex L. In the same period total of 12.574.160 of Narrowed leaved ash was produced, with continuous annual increase. In 2021, due to significant dieback of transplanted ash seedlings (during restoration activities) Croatian Forests Ltd. limit and then stop ash production. Share of European beech varies (from 5,5% in 2018 to 13,8% in 2017) and with its total production of 7.505.337 seedlings takes forth place in braodleaves production. Conducted analysis showed predominance of small number of tree species in production (pedunculate oak, sessile oak, common beach and narrow-leaved ash), which points to the conclusion that natural regeneration is strongly dependant on nursery production. Only small share (less than 5%) of other tree species is represented in production. Share of forest fruits, non native tree species (even highly productive and more resistant then domestic ones), pioneer species (used for growing needs of forest restoration) is relatively low. Importance of quality forest seed as prerequisite of successful nursery production is high, as well as importance of selection of apporpriate provenances and feature of forest planting material. Nursery production programmes need to be harmonised with real needs in practical forestry. Nevertheless, there is even stronger need of setting quality, multi-year nursery production plans, which will include a strong response to forthcoming challenges and threats, reduce risks in practical forestry and take into account international (scientific and expert) efforts, actual EU policies and growing needs of forestry and other sectors.
Key words: nursery production; forest reproductive material; broadleaf; production programme.
ĐODAN, Martina ŠL
GRADEČKI-POŠTENJAK, Marija ŠL
PERIĆ, Sanja ŠL
|Saša Bogdan, Ida Katičić Bogdan, Martina Temunović
| UDK 630* 232.3
|On the use of foreign forest reproductive material for the regeration of local stands of pedunculate oak from the stand points of a genetics