This paper presents the results of eight years of scientific research on the effect of polypropylene shelters (Tully tubes) and hydrophilic polymers on growth, survival, health and physiological ...condition of pedunculate oak seedlings ( Quercus robur L.). The experiment was established in 2014 on relative forest soil, on partially forested land in subcompartment 35a, forest management unit Kragujna, which is managed by the Forest Administration Vinkovci, Forest Office Županja. In the autumn of 2014, one-year-old bare-rooted pedunculate oak seedlings were planted as a randomized block design experiment - four blocks with four repetitions. Four types of planting were tested: seedlings without a polypropylene shelter, without the addition of Zeba hydrophilic polymer granules (S variant), seedlings without a polypropylene shelter, with the addition of Zeba hydrophilic polymer granules (SP variant), seedlings with a polypropylene shelter, without the addition of Zeba hydrophilic polymer granules (SS variant), and seedlings with a polypropylene shelter, with the addition of Zeba hydrophilic polymer granules (SSP variant). The experiment was established as a result of considering the long-term problem of difficulties in natural regeneration. Disturbances in natural regeneration are certainly caused by increasing climate changes (floods, long-term droughts, storms, hailstorms, etc.) and other unfavourable biotic and abiotic factors that cause a significant reduction in quantities and/or an almost complete absence of pedunculate oak acorn yield. Due to the aforementioned circumstances, in the very near future we will be forced to resort more often to different forms of artificial forest regeneration, such as regeneration by planting sheltered seedlings that are less exposed to risks and challenges during survival, and which have greater competitiveness in relation to other vegetation on the regeneration surface (higher growth). Nowadays, this method of regeneration is used mostly for filling in places where, for various reasons, natural regeneration has been unsuccessful on several occasions and over a long period of time, and/or where there are great difficulties in carrying out natural regeneration (floods, areas damaged by fires, game damages and competition of weeds). This paper presents the results of scientific research after five periodic measurements, i.e. after the first, second, fifth, sixth and eighth growing season. The results show that even after the eighth growing season, seedlings protected with a polypropylene shelter have greater survival rate and greater height growth than unprotected seedlings. The highest survival rate was found in seedlings protected with a polypropylene shelter, with the addition of Zeba hydrophilic polymer of 82.14% (SSP variant), while unprotected seedlings with the addition of Zeba hydrophilic polymer (SP variant) had the lowest survival rate of 62.63%. The highest growth was recorded on seedlings protected with a polypropylene shelter, with the addition of Zeba hydrophilic polymer (SSP variant) amounting to 202.75 cm, while on average the smallest seedlings were those without polypropylene shelter protection and without the addition of Zeba hydrophilic polymer (S variant), amounting to 129.02 cm.
Background and Purpose:
The declining and dieback of lowland oak forests as the result of global climate change, as well as the attack of various pathogenic organisms, industrial pollution, and other ...negative effects reduce acorn yield and will continue to do so in the future. As a result of this fact, the areas on which artificial regeneration will be applied by planting seedlings will have to be increased. The artificial regeneration process is more expensive than the natural one, so protection measures need to be applied to minimize the loss of young seedlings.
Materials and Methods:
Experimental plots were set up in the forest area of Spačva Basin. A completely randomized block design experiment in four repetitions was used, in which four variants of planting and protection of oak seedlings were examined. We tested polypropylene tree shelters and hydrophilic superabsorbent based on maize starch. Heights of the plants were measured by measuring tape, and survival was registered by numbering of dead and living plants. For statistical purposes, we have used analysis of variance (repeated measure ANOVA), which allows us to prove statistically significant difference between morphological traits of studied variants.
Results:
Two years after planting, the lowest level of survival was found in unprotected seedlings (79.5%), while tree shelters provided the best conditions for seedlings survival (88.75%). In the case with the hydrophilic granules Zeba the result is slightly worse. When analyzing average height in a particular case, significantly higher plants are recorded in cases where the polypropylene tree shelters are used. The average height, with tree shelters (128.27 cm), is more than three times higher than the unprotected seedlings (37.97 cm). The addition of hydrophilic granules did not show a statistically significant difference. In cases where the seedlings were not under the tree shelter protection, the effect of hydrophilic granules was also not statistically significant.
Conclusions:
Sheltering accelerated the height growth of the planted oaks substantially and also provided best conditions for seedlings survival. During the research period the usage of Zeba did not justify the purpose for which it was applied. Although the first results are promising in order to gain a complete insight into the potential of tree shelters it is necessary to record the changes and maintain the experiment for a further 2-3 years with quantification of other harmful factors that may appear (drought, game etc.) after which a more reliable judgment regarding their usefulness could be provided.
In the area of Croatian lowland forests, forwarders are usually used for extraction of timber assortments. Within the project »Systematization of norms for the production of timber assortments«, ...which was financed by the state company »Hrvatske šume« d.o.o. (»Croatian Forests« LLC), the process of development and implementation of new productivity norms for forwarders was carried out. Initially, for the execution of the research, it was necessary to gather data about technical characteristics of forwarders most frequently used in Croatia, but also around the world. The morphological analysis was performed and it was the basis for the classification of forwarders into classes. Three classes of forwarders were obtained after cluster analysis and load capacity appeared to be the most important factor. Machine performance was evaluated on 30 research sites. The standard method of time study (snap-back chronometric technique) was used. During the recording process, data of factors influencing forwarding (stand and terrain conditions) were collected. After analyzing the collected data, it was determined that the forwarding productivity depends on the forwarder class, average extraction distance, load characteristics, terrain and stand conditions. Regression analysis was used for identifying the time consumption of individual work components, and the productivity model for forwarding was developed. The obtained model was implemented into the application HsPPI. This is a part of the information system developed by IT Department of the state enterprise »Hrvatske šume« d.o.o. and is used for production planning in timber harvesting. The system is based on dBase IV databases and two main program modules. The main parts of the system are: tree marking data, assortment structure plan, production plan (felling, processing and extraction) and sales plan. Within a part of the production plan there is a module for calculating productivity norms for timber forwarding.
Background and Purpose: The process of joining the market competition by the company “Croatian Forests”, managing state forests in Croatia, is related to the transformation of the company into a ...trading company. This means that beside the biological and ecological goals in managing forests, the special attention is to be paid to business operations with the highest economic outputs, reduced costs and increased income. In order to enhance the regeneration of pedunculate oak forests in present day changing ecological and challenging economic conditions, as our proposal, is implementation of one of the artificial methods of regeneration pedunculate oak forests by planting seedlings protected with polypropylene tree shelters.
Materials and Methods: The paper deal with existing knowledge about the conditions and characteristics of two methods of oak stand regeneration and analyzed data of current norms, standards and prices for each of these methods. The analysis compared the two methods: method of regeneration with unprotected seedlings, and seedlings protected with polypropylene tree shelters.
Results and Conslusions: The research results showed that in comparison to the common seedling planting method, this method of pedunculate oak stand regeneration on difficult terrains with complex stand conditions is ecologically and economically more beneficial.
This paper deals with the present status of forest management in the Republic of Croatia with a special reference to forests managed by the company »Hrvatske šume« d.o.o. Zagreb, as well as to aims, ...tasks and methods of state-owned forest management, to conditions and trends in the number of the most significant forest machines used so far in forest harvesting. Also, the ways and activities are described by which »Hrvatske šume« d.o.o., in cooperation with the Faculty of Forestry, University of Zagreb, influence the trend of machine and technology development, as original solutions for meeting particularly demanding conditions of natural forest management.In the Republic of Croatia, the state owns 75% of the total area of forests and forest land, i.e. 2,018,987 ha are managed by »Hrvatske šume« d.o.o. »Hrvatske šume« d.o.o. carry out more than 50% of forest management activities by their own production forces and means. Therefore, the development of machines and technologies is a very significant precondition for improving business efficiency in severe terrain conditions, characterised by specific management methods. Four main criteria of suitability requirements, i.e. suitability of technical-technological solutions, can be singled out: Environmental suitability, Efficiency, Safety, Ergonomic suitability.These criteria have partly been established in line with modern international standards, applicable to conditions in the Republic of Croatia and partly by specific features of management conditions. The influence of »Hrvatske šume« on meeting the above requirements, and direct participation of »Hrvatske šume« in the development of technical-technological solutions suitable for certain conditions, have been shown on examples of development of two types of skidders and tractor assemblies for lowland forest thinning. Efforts are made to meet these requirements through tasks of the scientific-research work projects and in cooperation with the Faculty of Forestry, University of Zagreb, as well as by placing demands on and in cooperation with domestic manufacturers of machines and equipment.
Na osnovi poznavanja dimenzijskih značajki skidera s vitlom (osnovne dimenzije, masa vozila, položaj točke težišta), razvijen je model procjene kretnosti skidera za privlačenje drva uz nagib terena ...na siguran, djelotvoran i okolišno prihvatljiv način. Model je zasnovan na graničnom nagibu kretnosti skidera temeljem vučne značajke vozila, koji povezuje dva istraživačka pristupa, 1) vozilo – teren (raspodjela sila ovisno nagibu i vučenom teretu) te 2) kotač – tlo (procjena vučnih značajki skidera temeljem indeksa kotača), uz poštivanje niza ograničenja proisteklih iz prethodnih istraživanja: i) rasterećenja prednje osovine vozila, ii) preopterećenja stražnje osovine vozila, iii) najmanje uzdužne stabilnosti skidera, iv) najmanje nosivosti šumskog tla te v) dopuštenog opterećenja pneumatika.
Rezultati simulacijskog modeliranja procjene kretnosti skidera s vitlom Ecotrac 55V opremljenoga pneumaticima 12.4-24 pri privlačenju drva uz nagib terena, značajno se razlikuju s obzirom na uvjete nosivosti podloge te masu vučenih tereta. Kod manjih tereta, mase do 1 tone, kretnost skidera određuju kriteriji/ograničenja graničnoga nagiba kretnosti vozila (vučna značajka) i okolišne pogodnosti (najmanja nosivost podloge). Porastom težine tereta, osim nosivosti šumskog tla, odlučujući ograničavajući čimbenik kretnosti postaje odnos opterećenja prednje i stražnje osovine vozila (>1 : 3,5), koji ograničava kretnost skidera na terene nagiba <33 % kod tereta od 1,5 tone, tj. <20 % kod tereta od 2 tone. Kod tereta od 2,5 tone, na kretnost skidera, utječu kriteriji najvećeg dopuštenog opterećenja stražnje osovine skidera na nagibima <7 %.
Based on the dimensional characteristics of the cable skidder (dimensions, weight, position of the center of gravity), a model was developed for estimating the mobility of the skidder during timber extraction (skidding) uphill in a safe, efficient and environmentally sound way. The model is based on the limiting slope of skidders’ mobility depending on the traction performance of the vehicle, which connects two research approaches, 1) vehicle – terrain (distribution of forces depending on the slope and load) and 2) wheel – soil (traction performance based on wheel numeric). The model is in compliance with a number of restrictions arising from previous research: i) unloading the front axle of the vehicle, ii) overloading the rear axle of the vehicle, iii) minimum longitudinal stability of the skidder, iv) minimal soil bearing capacity and v) allowed tyre load capacity.
The results of the mobility of the cable skidder Ecotrac 55V equipped with 12.4-24 tires during skidding timber uphill, differ significantly with regard to the load-bearing capacity and the load size. For smaller loads, weighing up to 1 ton, the mobility of the skidder is determined by the criteria/limits of the skidder gradeability (traction performance) and environmental benefits (minimum load-bearing capacity). As the weight of the load increases, apart from the load-bearing capacity, the decisive limiting factor of mobility becomes the load ratio of the front and rear axles of the vehicle (> 1: 3.5), which limits the mobility of the skidder on slopes <33% for loads of 1.5 tons, <20% for 2 tons. At a load of 2.5 tons, the mobility of the skidder is affected by the criteria of the maximum allowable load of the rear axle of the skidder on slopes <7%.
U radu se istražuje povezanost postupaka pridobivanja drva i kretanja natječajnih cijena drva na panju. Istraživanje je provedeno na uzorku koji obuhvaća jednu šumsku regiju u Rumunjskoj, a cilj je ...bio utvrditi u kojoj mjeri pokazatelji pridobivanja prodanog drva utječu na natječajne cijene. Korišteni podaci Regionalne uprave šuma Baia Mare (RFA Baia Mare), Maramureş (slika 1), koja se sastoji od 13 šumarija, čine ugovore o sječi kroz tri godine gospodarenja (2012–2014). Autori smatraju da se navedeni podaci mogu smatrati reprezentativnim za rumunjske uvjete te mogu poslužiti kao ogledni primjer za svrhu istraživanja u ovoj studiji. Na temelju uzorka od 1192 potpisana ugovora, koji su obuhvaćali više od 20.000 ha sječne površine i više od 600.000 m3 užite drvne zalihe, na temelju deskriptivne statistike, dobiveni su modeli predviđanja budućih natječajnih cijena, ovisno o raznovrsnosti uvjeta pri pridobivanju drva. Značajke sustava pridobivanja drva kao što su: 1. vrsta sječe, 2. veličina sječine, 3. sječna gustoća, 4. dimenzije stabla, 5. nagib terena i 6. srednja udaljenost privlačenja drva, imali su prilično slab učinak na iznose natječajnih (početnih) (
R
2 = 0,20) i prodajnih (ostvarenih) cijena (
R
2 = 0,17), što pokazuje da se preostala varijabilnost cijena može odnositi i na druge čimbenike. Nije bilo jasno izraženih odnosa između odstupanja pokazatelja u sustavu pridobivanja drva i razlika u cijeni koju su ponuđači plaćali za kupnju drva na panju. Stoga je provedena detaljnija analiza cijena kako bi se vidjelo do koje se mjere cijene mogu objasniti promjenama u odnosu na ponudu i potražnju. Analiza je pokazala da je u razdoblju istraživanja došlo do povećanja potražnje drva na panju, istodobno i uz veću potražnju za vrstama četinjača. Rezultati ove studije mogli bi pomoći šumovlasnicima/šumoposjednicima pri gospodarenju šumama, ali i privatnim poduzetnicima u šumarstvu prilikom planiranja i vođenja njihovog poslovanja.
A survey of timber harvesting operations and tendering prices was conducted in a representative forest region of Romania aiming to see to what extent the harvesting parameters of the sold harvesting stacks affect the tendering prices. Based on a sample of 1192 contracts, accounting for more than 20,000 harvested hectares and for more than 600,000 harvested cubic meters, descriptive statistics of harvesting conditions and tendering prices were computed and prediction models of tendering prices as a function of harvesting conditions were estimated. Harvesting factors such as the felling type, sold volume, removal intensity, tree size and pruning condition, slope and extraction distance had rather a low effect on the initial (adj.
R
2 = 0.20) and final tendering prices (adj.
R
2 = 0.17) showing that the remaining variability could be related to other factors. No obvious relations were found between the variation of harvesting factors and the variation of the difference in price paid by the contractors to buy the wood. As a consequence, a more detailed price analysis was conducted to see to what extent prices can be explained by the demand and supply evolution. Although the evolution of the prices and negotiated quantities may be considered confusing in the context of a normal market supply and demand, the analysis revealed that the stumpage market demand increase during analyzed years and there was a bigger demand for conifers species. The results of this study could be of help for both, the forest management and harvesting contractors in shaping and conducting their businesses. In addition, the study gives detailed statistics on the forest operations practices and conditions under the Romanian forestry, being of help for comparisons with other regions.
Pri svakom je planiranju, pa tako i pri planiranju mreže šumskih prometnica, vrlo važno poznavati postojeće stanje, odnosno imati detaljan i točan uvid u postojeću mrežu šumskih prometnica područja ...zahvata otvaranja šuma, što omogućuje registar šumske prometne infrastrukture. Želi li se valjano procijeniti kvantiteta postojeće šumske prometne infrastrukture (gustoća šumskih prometnica), potrebno je jasno i nedvosmisleno definirati kriterije određivanja gustoće postojeće šumske prometne infrastrukture.U hrvatskome šumarstvu, trenutno važeće kriterije za određivanja gustoće primarne šumske prometne infrastrukture definiraju »Tehnički uvjeti za gospodarske ceste« (Šikić i dr. 1989), koji su u sažetom obliku uključeni u Pravilnike o uređivanju šuma (NN 111/06, NN 141/08) te (NN 79/15). Spomenuti su kriteriji nedovoljno precizni i nejasni te šumarskim stručnjacima prepuštaju donošenje niza subjektivnih odluka.Kako bi se izbjegla/smanjila svaka subjektivnost, dobili objektivni podaci te omogućila usporedivost izračunate gustoće primarne šumske prometne infrastrukture različitih gospodarskih jedinica, prišlo se izradi potpuno novih kriterija koji će poslužiti za precizno, objektivno i transparentno određivanje gustoće primarne šumske prometne infrastrukture. Kriteriji su razvijeni i detaljno opisani u okviru Obrasca za izradu Elaborata učinkovitosti mreže šumskih prometnica – primarne šumske prometne infrastrukture, koji je sastavni dio Pravilnika o provedbi mjere M04 »Ulaganja u fizičku imovinu«, podmjere 4.3. »Potpora za ulaganja u infrastrukturu vezano uz razvoj, modernizaciju i prilagodbu poljoprivrede i šumarstva«, tipa operacije 4.3.3. »Ulaganje u šumsku infrastrukturu« iz Programa ruralnog razvoja Republike Hrvatske za razdoblje 2014. – 2020. (NN 106/15, 65/17).U radu su na ortosnimkama prikazani te združeni sa fotografijom (slikovni dio registra primarne šumske prometne infrastrukture iz studije slučaja) najčešći/karakteristični primjeri primjene kriterija pri određivanju gustoće primarne šumske prometne infrastrukture.
In any planning, so even when planning the network of forest roads, it is an imperative to know the existing situation, and to have a detailed and accurate insight into the existing forest road ...network of the forest area in the process of opening, usually enabled by the forest traffic infrastructure registry. To validate the quantity of the existing forest traffic infrastructure (road density), it is necessary to precisely and unambiguously define the criteria for determining the density of existing forest traffic infrastructure.
In Croatian forestry, the currently valid criteria for determining the density of primary forest traffic infrastructure are defined by the »Technical Requirements for Economic Roads« (Šikić et al. 1989), which are summarised in the Forestry Management Regulations (NN 111/06, NN 141/08) and (NN 79/15). The criteria mentioned are insufficiently precise and unclear, which leaves the forestry experts to make a series of subjective decisions in calculating the density of primary forest traffic infrastructure.
To avoid/reduce any subjectivity, to obtain objective data and to make comparability of the calculated primary traffic infrastructure density of different management units, a set of completely criteria have been developed that will serve to accurately, objectively and transparently determine primary forest traffic infrastructure density. The criteria have been developed and described in detail in the Form for the Effectiveness Study of Primary Forest Road Traffic Infrastructure, an integral part of the Bylaw on measure implementation M04 »Investments in physical assets«, by-measure 4.3 »Grant for investments in development, modernization and customization of agriculture and forestry«, operation type 4.3.3. »Investments in forest infrastructure« from the Program of Rural Development in the Republic of Croatia in the period from 2014 to 2020 (NN 106/15, 65/17).
The most frequent/characteristical examples of the application of criteria in determining the primary forest traffic infrastructure density are presented in the paper based on orthophoto maps together with photographs (image part of the primary forest traffic infrastructure registry from case studies).
Pri svakom je planiranju, pa tako i pri planiranju mreže šumskih prometnica, vrlo važno poznavati postojeće stanje, odnosno imati detaljan i točan uvid u postojeću mrežu šumskih prometnica područja zahvata otvaranja šuma, što omogućuje registar šumske prometne infrastrukture. Želi li se valjano procijeniti kvantiteta postojeće šumske prometne infrastrukture (gustoća šumskih prometnica), potrebno je jasno i nedvosmisleno definirati kriterije određivanja gustoće postojeće šumske prometne infrastrukture.
U hrvatskome šumarstvu, trenutno važeće kriterije za određivanja gustoće primarne šumske prometne infrastrukture definiraju »Tehnički uvjeti za gospodarske ceste« (Šikić i dr. 1989), koji su u sažetom obliku uključeni u Pravilnike o uređivanju šuma (NN 111/06, NN 141/08) te (NN 79/15). Spomenuti su kriteriji nedovoljno precizni i nejasni te šumarskim stručnjacima prepuštaju donošenje niza subjektivnih odluka.
Kako bi se izbjegla/smanjila svaka subjektivnost, dobili objektivni podaci te omogućila usporedivost izračunate gustoće primarne šumske prometne infrastrukture različitih gospodarskih jedinica, prišlo se izradi potpuno novih kriterija koji će poslužiti za precizno, objektivno i transparentno određivanje gustoće primarne šumske prometne infrastrukture. Kriteriji su razvijeni i detaljno opisani u okviru Obrasca za izradu Elaborata učinkovitosti mreže šumskih prometnica – primarne šumske prometne infrastrukture, koji je sastavni dio Pravilnika o provedbi mjere M04 »Ulaganja u fizičku imovinu«, podmjere 4.3. »Potpora za ulaganja u infrastrukturu vezano uz razvoj, modernizaciju i prilagodbu poljoprivrede i šumarstva«, tipa operacije 4.3.3. »Ulaganje u šumsku infrastrukturu« iz Programa ruralnog razvoja Republike Hrvatske za razdoblje 2014. – 2020. (NN 106/15, 65/17).
U radu su na ortosnimkama prikazani te združeni sa fotografijom (slikovni dio registra primarne šumske prometne infrastrukture iz studije slučaja) najčešći/karakteristični primjeri primjene kriterija pri određivanju gustoće primarne šumske prometne infrastrukture.
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