Energy Return on Investment (EROI) of Different Wood Products

Energy cannot be produced without consumption of some part of the energy, and the proportions in which this occurs are a key indicator of the efficiency of the production process. Energy return on investment (EROI) of energy production shows the relationship between obtained and invested energy in the production process. This relationship is a key factor in sustainable global energy supply. Wood chips and one-metre firewood are used to produce thermal energy. Amount of energy obtained by burning depends on the moisture content and the features of the energy plant. This chapter deals with the issue of the amount of energy required to produce in the process of wood chips and one-metre firewood production and its transport to the heating plant. When calculating the energy balance, it is important to include as many input parameters as possible (parameters of energy consumption), which represents an almost impossible task because one parameter directly binds several others. According to several authors, the relationship between obtained and invested energy or EROI for energy wood is 30:1 which is a better ratio than the production of oil, for which relationship between obtained and invested energy is about 20:1. The results of study show that most of the energy during the production and supply of energy wood products from final felling of oak stands is used for fuel for machinery and vehicles in the production process. Ultimately, the relationship between obtained and invested energy is approximately 25:1 in the case of moisture content in the wood chips in the limit (market) value of 35% and the mean distance truck transportation of wood chips of 50 km. The relationship of obtained and invested energy used for one-metre firewood is bigger than 25:1 because of less invested energy which does not include machines like wood chipper. This is a satisfactory relationship, but it decreases with a greater transport distance. Such is the case when chips manufactured in Croatia, due to the lack of heat plants, are transported over long distances to neighbouring countries

Analysis of an existing forest road network

resources needed to plan these improvements, it is important to target these efforts based upon the available information. Previous research based on existing forest compartment and road network data produced the concept of a methodological study of forest accessibility. Six optimisation stages were defined. This paper deals with the first stage – Analysis of the existing primary forest road infrastructure network. This stage analyses the quantity and quality of the existing forest road network. The results of this analysis, obtained by use of Geographic Information System (GIS), help the forest manager to allocate efficiently the resources to specific forest areas. The results of the analysis are based on data that are easily obtained with GIS. The analysis model is sensitive to the situation on the ground and yet easily implemented. GIS measures of skidding distance, skidding costs and desirable accessibility are included in the model. Relative accessibility and forest road network efficiency are two important calculated results. The paper presents a detailed escription of each step of this work stage. The process is demonstrated on two mountainous Management Units within the Forestry Office Opatija, Forest Administration Buzet

Surface Accessibility with Spatial Analysis During Fire Extinguishing Procedures: Example on the Island of Vis

Background and Purpose: The existing public and forest transport infrastructure (truck forest roads) are permanent objects used when passing through forests. They also serve as a firefighter belt and provide direct access to firefighting vehicles, or are used as the starting point where firefighting teams extinguish fires or move toward remote fires. The paper identifies the existing fire road network (including public roads, forest roads, non-classified roads and fire roads) for access of firefighting vehicles during fire extinguishing interventions. Material and Methods: An analysis of the intervention rate was conducted on a dispersive sample (35 positions) from two volunteer fire associations (VFA) on the island of Vis. Also, an analysis of the surface availability to fire vehicles concerning the time of departure from the fire station was conducted, as well as the comparison with the Standard time of intervention defined by the regulations on fire department organization in the Republic of Croatia. Results: For each simulated fire location for intervention of two existing volunteer fire associations: VFA Komiža and VFA Vis, results show that for a few fire locations, despite a smaller distance from the VFA Komiža, a quicker intervention is possible from the VFA Vis (locations 4, 5 and 14), and vice versa (locations 21, 22 and 25). With the use of a New Service Area, tool intervention times regarding different areas were calculated. Intervention times were divided into intervals: 25 min. The last two categories of area are beyond reach for firefighters within the Standard time of intervention (15 min) and together they comprise to 27.88% of the total research area. Conclusions: The results of Closest Facility tool indicate that for the simulated fire position the best/fastest route is not always the shortest one, because of a significant effect of the structural elements of each road, the state of the road and the longitudinal slope of the road itself. One of the possible approaches to gain access to the area for fire-fighting, as well as to prioritize fire roads regarding maintenance/reconstruction is to improve road conditions, and thus increase the average driving speed

Development of a new method for assessing condition of forest road surface

U radu se analizira nova metoda za procjenu stanja površinskog sloja šumskih cesta mjerenjem vibracija. Istraživanje je provedeno na dijelu šumske ceste tijekom vožnje vozila opremljenog mjernim uređajem kojim se mjere vibracije u sve tri osi, položaj i brzina vozila te vrijeme. Ispitivanja su provedena u oba smjera vožnje na dijelu ceste s različitim frekvencijama mjerenja, tlakovima u gumama i brzinama vožnje. Na temelju rezultata mjerenja stanja površinskog sloja šumske ceste preporučuje se frekvencija snimanja od 10 Hz, brzina vozila od 20 km/h te tlak u gumama od 2 bara.A new method for assessing condition of forest road surface layers by vibration measurements is analysed in the paper. The research was conducted on a forest road segment while driving a vehicle equipped with a measuring device for determining vibrations in all three axes, vehicle position, vehicle speed, and time. Tests were performed in both driving directions of the forest road segment using different measuring frequencies, tyre inflation pressures, and driving speeds. The recording frequency of 10 Hz, vehicle speed of 20 km/h, and tyre inflation pressure of 2 bars, can be recommended based on the forest road surface measurement results

Current Status and Perspectives of Forestry Entrepreneurship in Croatia

Background and Purpose: The relevance and importance of forestry entrepreneurship is constantly increasing, especially in countries with high transition dynamics in forestry sector. In Croatia, forestry entrepreneurs have in short time become an indispensable part in the performing of harvesting and other types of forestry operations. This paper presents the current status and perspectives of forestry entrepreneurship in Croatia. Materials and Methods: Based on the analysis of the available data from various sources (normative state acts, Forestry Chamber’s official registries, databases and documents, state forestry company business reports etc.), this paper provides an overview of the legal and institutional framework for the activities of private entrepreneurs in Croatian forestry with particular attention to licensing forestry contractors and the role of the Croatian Chamber of Forest and Wood Technology Engineers (Forestry Chamber). Results and Conclusions: The paper explains the activities, tasks, organization structure and formal bodies of the Forestry Chamber. The licensing model is also presented together with the formal criteria and minimum conditions which forestry entrepreneurs have to fulfill in order to acquire a license for forest work operations. Structural characteristics and the profile of forestry entrepreneurs is given by the number, size and type of business, the type of forest operations for which they are licensed, and the volume of work that they are performing for Croatian Forests Ltd, the state forest company. Finally, the paper includes some reflections on the perspectives and possibilities for improving the status of entrepreneurship in Croatian forestry

Promjene nekih vrijednosnih kriterija šumskih radnika u 15-godišnjem razdoblju

U radu se prikazuju rezultati ispitivanja mišljenja i stavova proizvodnih šumskih radnika. Svrha je istraživanja bila ispitati i obrazložiti neke vrijednosne kriterije šumskih radnika te prikazati njihove eventualne promjene u 15-godišnjem razdoblju. Istraživanje je obavljeno anketiranjem uz pomoć unaprijed pripremljenoga, odnosno 1998. godine prvi put provedenoga upitnika. Anketiranje provedeno tijekom 2012/13. godine i usporedba s rezultatima iz 1998. godine omogućili su uočavanje promjena u nekim pokazateljima za dvije promatrane, vremenski udaljene skupine ispitanika. Ispitivanja su obuhvatila: (1) opće i socioekonomske pokazatelje radnika, (2) odabir profesije, osposobljavanje za rad i poželjne osobine radnika, (3) procjenu zaštite zdravlja i sigurnost radnika, (4) vrijednosne i tehnološke kriterije prema radu, (5) zaštitu prava iz rada zaposlenika, (6) svakodnevne interese radnika i očekivanja u neposrednoj budućnosti, (7) ocjenu istraživanja, strukture upitnika i sadržaja pitanja. Rezultati istraživanja u jednom dijelu pokazatelja: a) odražavaju određena povoljna kretanja i pozitivne pomake ostvarene u promatranom razdoblju – sigurnost i zdravlje radnika, odnos prema radu, odabir profesije i sl.; b) upućuju na zaustavljanje nepovoljnih trendova – djelotvornost organiziranosti radilišta, eksploatacijsko stanje strojeva; c) upućuju na daljnje pogoršanje stanja ili nastavak nepovoljnih kretanja – pad životnoga standarda, osposobljavanje za rad u šumi, svakodnevna psihička opterećenja radnika i dr

Mobilne aplikacije – korisna inovacija u šumarstvu?

Razvojem i napretkom mobilne tehnologije promijenila su se gledišta u prikupljanju, obradi i interpretaciji različitih terenskih podataka u svim strukama, pa tako i u šumarstvu. U obavljanju stručnih šumarskih poslova mobilne aplikacije dosada nisu zamijenile tradicionalne šumarske instrumente i postupke. Međutim, na tržištu se pojavljuje sve veći broj aplikacija koje su namjenski razvijene za šumarstvo ili koje se osim u drugim područjima također mogu koristiti i za obavljanje nekih šumarskih zadaća. S tim u vezi, u ovom se radu daje pregled mobilnih aplikacija koje je moguće primijeniti u šumarstvu. Prikazane aplikacije odabrane su, uz postavljene kriterije, pretraživanjem digitalnih servisa Google Play i App Store. Nakon opisa namjene i načina rada odabranih aplikacija posebno su istaknuta njihova glavna obilježja te pozitivne i negativne strane svake pojedine aplikacije. Cilj je rada procijeniti u kojoj mjeri mobilne aplikacije doista mogu biti korisna inovacija u šumarstvu. Prikazom odabranih aplikacija pružaju se spoznaje o tome je li u šumarstvu moguća profesionalna primjena mobilnih aplikacija

Mogućnosti primjene gabiona

Gabioni su žičane košare ispunjene kamenom, ali ispuna može biti i od drugoga materijala (cigla, drvo, ukrasno staklo). Počeci upotrebe takvih sustava sežu još u najranije civilizacije, a svoju su primjenu zadržali do danas. Tri su osnovna oblika gabiona: gabionska košara, gabionski madraci i vrećasti gabioni. Gabionske košare uglavnom služe (Brooks i Nielsen 1992) kao potporni ili ogradni zid, a rjeđe kao stabilizacija. Gabionski su madraci svojevrsni žičani »jastuci« ispunjeni kamenim materijalom koji služi za oblaganje riječnih korita, kanala, potoka i bujica radi regulacije vodenih tokova i sprečavanja erozije tla. Vrećasti gabioni (gabionske vreće) u posljednje se vrijeme najčešće upotrebljavaju pri radovima na učvršćivanju korita rijeka i podnožja nasipa. Gabioni danas služe u mnogim područjima ljudske djelatnosti, a najvažniji je doprinos zaštitna funkcija pri regulaciji vodotokova i pokosa na cestama. Stabilizacija i utvrđivanje nasipa gabionima potvrđuje njihovu široku primjenu. Dodatan je doprinos i njihova dekorativna funkcija zbog koje se upotrebaljavaju pri uređenju okoliša. Zbog široke mogućnosti primjene gabione danas priznaje većina inženjera diljem svijeta kao standardni građevinski materijal. Prednosti i nedostaci primjene gabiona polazna su točka u njihovoj upotrebi te poticaj za daljnja istraživanja