Assessment of timber extraction distance and skid road network in steep karst terrain

This study aims to define a simple and effective method to calculate skidding distances on steep karst terrain, rich in ground obstacles (stoniness and rockiness) to support decision planning of secondary and primary forest infrastructure network for timber extraction in productive selective cut forests. Variations between geometrical extraction distances and actual distances were highlighted on the operational planning level (i.e., compartment level) through GIS-related calculation models, focusing on cable skidder timber extraction. Automation in defining geometrical and real extraction distances, as well as relative forest openness were achieved by geo-processing workflows in GIS environment. Due to variation of extraction correction factors at the compartment level from a minimum of 1.19 to a maximum of 5.05 in the same management unit, it can be concluded that planning harvesting operations (timber extraction) at operational level should not include the use of correction factors previously obtained for entire terrain (topographical) categories, sub-categories or even management units

CAN BIOMASS TRIGGER AN ENERGY-WISE TRANSITION IN CROATIA AND REST OF SOUTHEASTERN EUROPE?

Šumska biomasa predstavlja važan izvor energije, čijem bi se korištenju u budućnosti trebalo posvetiti znatno više pozornosti. Biomasa u svojim tradicionalnim oblicima je i dalje vrlo važan izvor energije u većini zemalje Jugoistočne Europe, te će u doglednoj budućnosti i dalje biti tako. Međutim, sve se više koristi ne samo za proizvodnju toplinske energije, već za proizvodnju električne i rashladne energije, i to se smatra kao važan dio energijske tranzicije koja je obećavajući model s visokim ekonomskim i ekološkim prednostima. Korištenje energije biomase pruža znatne mogućnosti za otvaranje novih radnih mjesta, te tako može imati znatan pozitivan utjecaj na lokalno i nacionalno gospodarstvo. U radu se opisuje trenutnu fazu energijske tranzicije u zemljama jugoistočne Europe ti ulogu šumske biomase u njegovoj provedbi. Analizirani su primjeri i događanja u Albaniji, Bosni i Hercegovini, Hrvatskoj, Makedoniji, Kosovu i Srbiji. Uporaba biomase kao energenta u ruralnim područjim, potiče stvaranje dodatnih prihoda, povećava proizvodnost te omogućava otvaranje malih seoskih poduzeća. Iz makroekonomske perspektiv, uporaba biomase doprinosi svim bitnim elementima razvoja zemalja jugoistočne Europe.Ključni pokretači, kao i prepreke na koje se može naići pri energijskoj tranziciji u jedinicama lokalne samouprave, mogu se strukturirati kao; poticaj iz potencijala, poticaj od tržišta korištenje trgovačkih i poslovnih veza, biti prvi ili lokalni ponos, zadržati novac kod kuće.U radu je prepoznat velii broj potencijalnih skupina prepreka za korištenje šumske biomase; gospodarska ograničenja, financijska ograničenja kao ozbiljna prepreka za mnoge lokalne samouprave, društvena ograničenja, ograničenja u ljudskim resursima, ograničenja zbog transparentnosti te na kraju tehnička ograničenja.Through the history of mankind, until the mid-19th century, biomass, particularly wood, represented the most important source of energy. In many countries of Europe, the awareness of the importance of forest biomass as fuel has been closely connected to the general understanding and the realization of own and world energetic situation. Forest biomass represents an important source of energy, whose use should be paid more attention to in the future. In its traditional forms, biomass is still a very significant source of energy in most countries of the southeast Europe and it will continue to be so in the near future. However, it is more and more used not just for thermal energy production, but also for the production of electric and cooling energy which is considered as an important part of the energetic transition which is a promising model with high economic and ecological advantages. The use of biomass energy offers significant possibilities for opening new jobs, thus having a significant positive impact on the local and national economy. This paper describes the present stage of the energetic transition in the south-eastern European countries and the role of forest biomass in its implementation. Examples and events in Albania, Bosnia and Herzegovina, Croatia, Macedonia, Kosovo and Serbia are analysed. Rural development projects as well as the use of bioenergy biomass has a great potential for income generation, increase of productivity and opening of small village companies. From the macroeconomic perspective, the use of biomass contributes to all the important elements in the development of the south-eastern European countries.Key drivers as well as the obstacles which can be encountered in the energetic transition in local government units can be structured as follows; potential stimulus, refers to the most south-eastern European countries regarding their significant afforestation and forest biomass potential, market stimulus due to cost-effective accessible plants and equipment for biomass, as well as the adequate support of manufacturing firms, the use of commercial and business connections: where most of biomass trades among the south-eastern European countries and EU is carried out in integration with the forest product trade, to be first or the local pride, is an important driver in the south-eastern European countries to keep money at home is another important link with the positive perception in the use of the forest biomass. The paper recognised a significant number of potential groups of obstacles for using the forest biomass; economic limitations more favourable price of the forest biomass energy in relation to fossil fuels, financial limitations as a serious obstacle for each form of the renewable energy, social limitations are very specific for each form of the renewable energy, human resource limitations since most local governments do not have sufficient human potential, limitations due to transparency are a very frequent problem, primarily depends on the democratic power, technical limitations mostly belong to the fact that most of the equipment for using renewable energy sources and the increase in energetic efficiency from the import, has not been produced on the local level

Soil Measurements in the Context of Planning Harvesting Operations and Variable Climatic Conditions

Background and Purpose: Terrain trafficability and vehicle mobility during timber extraction are highly influenced by terrain characteristics, as well as by soil bearing capacity. Insufficient planning, too heavy vehicles, excessive traffic, poor soil knowledge, together with bad weather conditions, cause severe disturbance to forest soil. Damage to the forest ecosystem arises due to felling and timber extraction operations, regardless of the technical means used in this process. Traffic intensity plays an essential role in soil compaction because deformations can increase with the number of passes, which may lead to excessive soil disturbance. Materials and Methods: The research was conducted in Zalesina, a hilly and pre-mountainous part of Gorski kotar, Croatia, in two management units (MUs) comprising of 569.64 ha of selective beech and fir forests. Physical and mechanical properties of forest soil, essential for vehicle mobility and terrain trafficability during timber extraction are based on measuring the following soil parameters: 1) soil penetration resistance, 2) soil shear strength, and 3) current soil moisture. Measurements were made during one calendar year, on five sampling plots (three in MU "Belevine" and two in MU "Kupjački vrh") chosen on the prevailing soil types in both MUs. Results: The highest values of cone index and shear strength were recorded in July which was the warmest and driest month with only 7 rainy days. Current soil moisture was the lowest in July at φ=15.26% vol, while the lowest values of cone index were from October to January with precipitation at its climax from September to January with cumulative 1232 mm of rain and 846 cm of snow. Lower values of penetration resistance were in MU "Kupjački vrh" at 0.96 MPa, which is related to overall terrain structure of high karst and surface roughness, making the sampling of plots difficult. By comparing cone index values (CI15) and the mean values between 5 and 25 cm of depth (CI5-25), the variation coefficient indicates a lower variability of CI5-25 values on four out of five sampling plots. However, t-test showed no statistically significant difference between these soil parameters. Conclusions: Data regarding soil bearing capacity in a map form as an additional layer to other maps of stand characteristics would ensure better opportunities for planners or operators to reduce and avoid rutting and soil compaction. Measured data on penetration resistance, soil shear strength and current soil moisture have not only given in a simple and a fast manner the in situ stand conditions, but they have also shown their dependence on climatic conditions

LCA Studies in Forestry – Stagnation or Progress?

Today, LCA is one of the leading and most used tools for environmental management, but the application of LCA in forestry is still in an initial phase. Due to a high amount of different wood products which can be produced in forestry sector, production of raw material itself is not included enough in the whole LCA process. Raw wood products and biomass used to be widely declared as »carbon neutral« and renewable, but production steps have a significant influence on the environmental impact depending on machinery used, opening forest with new roads, management type (clear-cut, even-aged management or selective cut), etc. This paper gives a review of LCA studies in forestry based on three segments: harvesting operations biomass for energy road construction and maintenance

Round Wood Waste and Losses – Is Rationalisation in Scaling Possible?

The term »loss« should be distinguished from the term »waste« commonly used by forestry practitioners to indicate the difference between gross volume (planned production based on official tariffs) and net volume (produced timber volume) of trees. Volume loss in round wood refers to the difference between the actual volume of round wood and the volume determined based on the prescribed method of measurement and calculation. As a result of prescribed scaling methods and calculations, volume losses appear due to 1) used volume equations, 2) prescribed method of measurement (i.e. measurements of length and mid-length diameter) and 3) deduction of double bark thickness. In Croatia, round wood is cross-cut and transported with bark, while logs are measured and sold without bark. In this way, the bark is an unnecessary ballast in production, but has many possible applications such as energy source, in the production of wooden boards in construction, in nurseries and horticulture, etc. The research was conducted on 225 butt-logs of sessile oak (Quercus petraea (Matt.) Liebl.) ranging in diameter classes from 27.5 cm to 67.5 cm from even-aged forests in the central part of Croatia. Deduction of double bark thickness caused a higher average loss in the volume when using Huber’s equation at 14% and when using Riecke-Newton’s equation at 13.5%. In both volume estimation methods, the loss due to double bark thickness was slightly reduced exponentially as the diameter of but-logs increased. The determined dependence of the bark thickness on diameter of butt-logs over bark indicates the need for correction of the bark deduction tables that are in operational use in Croatian forestry and are provided by trading practices, and since they are not the result of scientific research, they lead to unfair payment between sellers and buyers of round wood. Comparison analysis of the simulation of butt-logs indicated that the introduction of Riecke-Newton’s equation for estimating the volume of commercially important assortments in Croatian forestry is justified. The use of Riecke-Newton’s equation in these terms leads on average to a 6.6% higher volume of butt-logs than the use of Huber’s equation for estimating the volume of assortments

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

Studija primarnoga otvaranja šuma gospodarske jedinice Crno jezero – Marković rudine Šumarije Otočac

Kvalitetno isplanirana i u šumski ekosustav optimalno uklopljena šumska prometna infrastruktura jedan je od osnovnih preduvjeta potrebnih za današnje racionalno gospodarenje šumskim ekosustavom. Ukupna količina šumskih prometnica, njihov razmještaj u prostoru te njihove propisane tehničke značajke moraju biti dostatne za što kvalitetnije upravljanje šumom. Ako je šumska prometna infrastruktura pravilno položena u prostoru, ona omogućuje izvođenje svih zadataka predviđenih šumskogospodarskim planovima na određenom šumskom području, uz minimalne troškove njihove izgradnje i održavanja uz maksimalan učinak. U ovom radu prikazano je sadašnje stanje primarne otvorenosti gospodarske jedinice Crno jezero – Marković rudine te su predložene smjernice njezina daljnjega otvaranja s ciljem dostizanja vrlo dobre primarne relativne otvorenosti. Terenski su podaci obrađeni u računalnim programima ArcGIS 10.4 i QGIS 2.18.20. Ustanovljeno je da klasična otvorenost šuma u toj gospodarskoj jedinici iznosi 13,66 km/1000 ha, što ne udovoljava ni minimalno propisanoj klasičnoj otvorenosti koja za gorsko-planinsko reljefno područje iznosi 15 km/1000 ha. Analizirajući rezultate primarne relativne otvorenosti, zatečeno je vrlo slično stanje kao i kod klasične otvorenosti: primarna relativna otvorenost iznosi 45,05 %, što se smatra nedovoljnom primarnom relativnom otvorenošću. Nadalje, analizirana je postojeća srednja geometrijska udaljenost privlačenja drva za svaki odsjek zasebno te je utvrđeno da taj parametar na razini gospodarske jedinice iznosi 258,74 m. Pomnim planiranjem projektirano je ukupno 53,05 km novih trasa šumskih cesta, što je u konačnici rezultiralo povećanjem klasične otvorenosti šuma na 22,82 km/1000 ha, primarne relativne otvorenosti na 75,8 % te smanjenjem srednje geometrijske udaljenosti privlačenja drva na 140,55 m

Proizvodnost traktora Ecotrac 120V pri privlačenju drva u brdskom području središnje Hrvatske

U radu su prikazani rezultati istraživanja proizvodnosti rada skidera Ecotrac 120V na privlačenju drva poludeblovnom metodom iz proredne i dovršne sječine. Terensko je istraživanje provedeno studijem rada i vremena. Razlike u obujmu tovara, brzini vožnji, izvlačenju užeta i privitlavanju te razlike u utrošku vremena pojedinih radnih zahvata na sječini i rada na pomoćnom stovarištu istražene su t-testom. Za radne zahvate za koje je utvrđena značajna razlika između promatranih sječina u daljnjim su izračunima primijenjene individulne prosječne vrijednosti za pojedinu sječinu, dok su kod ostalih radnih zahvata izračunate nove, zajedničke prosječne vrijednosti. Utrošci vremena vožnji izračunati su na temelju prosječne brzine i udaljenosti privlačenja. Utvrđena je značajna razlika između obujma tovara iz proredne i dovršne sječine. Razlike su u utrošku vremena najočitije u skupini radnih zahvata na sječini, a nastaju kao posljedica različite udaljenosti izvlačenja užeta i privitlavanja tovara. Projektirani dnevni učinak u dovršnom je sijeku prosječno 21 % veći nego u prorednoj sječi uz prosječno 26 % niže jedinične troškove. Detaljnom analizom utrošaka vremena pojedinih radnih zahvata utvrđeno je da na razliku u proizvodnosti i troškovima bitan utjecaj imaju sječna gustoća sastojine i prosječan obujam posječenoga stabla. Različita sječna gustoća utječe na različit utrošak vremena rada na sječini i posljedično na ostvarivi dnevni učinak. Na proizvodnost rada skidera uz sječnu gustoću još veći utjecaj ima prosječni obujam posječenoga stabla jer omogućuje formiranje tovara zadovoljavajućega obujma na kratkoj udaljenosti privitlavanja vezivanjem manjega broja komada, često uz upotrebu samo jednoga bubnja vitla. Stoga se može zaključiti da mogućnost postizanja najvećih učinaka u zadanim sastojinskim i eksploatacijskim uvjetima leži u optimalnom odnosu između veličine tovara i vremena utrošenoga pri radu na sječini koje je nužno za njegovo formiranje

The effectiveness study of primary forest road traffic infrastructure – an alternative to study of primary forest opening or just a short-term solution?

Planiranje šumskih prometnica, kao prva, nezaobilazna i vrlo važna faza uspostavljanja optimalne/najbolje moguće mreže primarne šumske prometne infrastrukture na terenu, može biti na: 1) strateškoj, 2) taktičkoj te 3) operativnoj razini. Strateško i taktičko planiranje odnose se na planiranje cjelokupne mreže primarnih šumskih prometnica, dok se operativno planiranje odnosi na planiranje pojedinačne šumske ceste. Rezultat taktičkog planiranja primarnih šumskih prometnica je, ili bi bar trebala biti, Studija primarnog otvaranja šuma pojedine gospodarske jedinice (dalje: Studija).Nepostojanje (pod)zakonske obveze izrade Studije, dokumenta u kojemu bi se objedinili svi rezultati rada pri taktičkom planiranju primarne šumske prometne infrastrukture na razini gospodarske jedinice, predstavlja velik problem pri optimizaciji primarne šumske prometne infrastrukture, poglavito neotvorenih ili nedovoljno otvorenih šuma. Unatoč čestom ukazivanju na navedeni problem, ali i na mogućnosti njegova rješavanja/umanjenja, kroz značajan broj radova različitih autora koji su se u svojem znanstvenom radu bavili problematikom otvaranja šuma, rezultati istraživanja i konkretne preporuke do danas nisu naišle na širu primjenu u operativnome šumarstvu.Tijekom izrade Programa Ruralnog razvoja Republike Hrvatske za razdoblje 2014.–2020. (dalje: Program), EU je zatražila od Republike Hrvatske da osmisli dokument kojim će se analizirati i ocijeniti kvantiteta i kvaliteta prostornog rasporeda primarne šumske prometne infrastrukture određene gospodarske jedinice, utvrditi potreba daljnjega primarnog otvaranja šuma, definirati položaj idejnih trasa planiranih šumskih prometnica te uskladiti gustoća mreže primarnih šumskih prometnica na taktičkoj razini s preporučenim vrijednostima pojedinog reljefnog područja na strateškoj razini planiranja primarne šumske prometne infrastrukture.U okviru 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) (dalje: Pravilnik) se nalazi prilog 1 – Obrazac za izradu Elaborata učinkovitosti mreže šumskih prometnica – primarne šumske prometne infrastrukture (dalje: Elaborat), koji je u potpunosti zadovoljio postavljene kriterije EU.U radu se: 1) kritički raščlanjuju osnovne sastavnice Elaborata s posebnim naglaskom na njegovu sastavnicu B. – Analiza postojeće mreže primarne šumske prometne infrastrukture, 2) detaljno pojašnjava metodologija izrade registra primarne šumske prometne infrastrukture, 3) opisuju novodefinirani kriteriji određivanja gustoće primarne šumske prometne infrastrukture, 4) u odnos se radi međusobne usporedbe dovode Elaborat i Studija, te 5) donose se preporuke o budućim aktivnostima usmjerenima ka poboljšanju taktičkog planiranja primarne šumske prometne infrastrukture.The Effectiveness Study of Primary Forest Road Traffic Infrastructure – an alternative to Study of Primary Forest Opening or just a short-term solution?Planning forest roads, as the first, inevitable and very important stage in establishing optimal i.e. best possible primary forest traffic infrastructure network, can be on: 1. strategic, 2. tactical and 3. operational level. Strategic and tactical planning level relate to planning of the entire primary forest road network, while operational planning refers to the planning of an individual forest road. The result of the tactical planning of primary forest roads is, or at least should be, the Study of Primary Forest Opening of an individual management units (hereinafter: The Study).The absence of legal obligation in producing the Study, the document in which all work results of tactical planning primary forest traffic infrastructure, at the management unit level, would be consolidated, is a major problem in the optimization of primary forest traffic infrastructure, particularly in unopened or insufficiently opened forest areas. Despite frequent emphasizing to this problem and the possibilities of its solving/reduction, a significant number of papers by various authors who have in their scientific work dealt with the issue of forest opening, research results and applicable recommendations are still not used broadly in practical forestry.While establishing Program of Rural Development in Republic of Croatia in period from 2014 to 2020, EU authorities have requested from Croatian authorities a document which includes analysis and evaluation data, regarding the quantity and quality of the primary forest traffic infrastructure network spatial distribution of a specific management unit, which will determine the need of further primary forest opening, which will also define concept design alignment of planned forest roads and will accord primary forest road density at the tactical level with the recommended values of individual relief area categories on the strategic level of primary forest traffic infrastructure planning.In 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 Republic of Croatia in period from 2014 to 2020 (NN 106/15) (hereinafter: The Bylaw) holds an appendix No. 1 – Form for the Effectiveness Study of Primary Forest Road Traffic Infrastructure (hereinafter: The Effectiveness Study), which was completely satisfactory to EU authorities’ requests.This paper will: 1) critically analyze the basic components of the Effectiveness Study with special emphasis on the component B – Analysis of the existing primary forest traffic infrastructure network, 2) explain in details the methodology of primary forest traffic infrastructure registry production, 3) describe the newly defined criteria for determining density of primary forest road infrastructure, 4) define the relationship and differences of the Effectiveness Study and the Study of Primary Forest Opening, and 5) give recommendations on future activities aimed at improving tactical planning of primary forest traffic infrastructure

Otvorenost gospodarske jedinice Belevine, NPŠO Zalesina, i prijedlog daljnjega otvaranja

Jedan od preduvjetâ potrebnih za racionalno gospodarenje šumskim ekosustavom svakako je kvalitetna šumska prometna infrastruktura. Nedovoljna otvorenost i nepovoljan razmještaj u prostoru primarne i sekundarne prometne infrastrukture stvara probleme u gospodarenju šumama te poskupljuje pridobivanje drva. U ovom je radu prikazano sadašnje stanje primarne i sekundarne otvorenosti gospodarske jedinice Belevine te srednje stvarne udaljenosti privlačenja drva na razini odjela/odsjeka. Iznesen je i prijedlog daljnjega otvaranja prostorno izdvojenoga odjela 18. Odjel 18 najmanje je otvorena površina te gospodarske jedinice (GJ) i u potpunosti je okružen privatnim površinama. U raščlambi parametara otvorenosti istraživanoga područja primijenjeni su programi ArcGIS 10.1 i QGIS 2.14.3. U istraživanoj GJ srednja stvarna udaljenost privlačenja drva iznosi 156,7 ± 127,3 m, s najvećom udaljenosti od 762 m i ukupnim faktorom privlačenja drva od 2,02. Analiza faktora privlačenja drva na razini odjela/odsjeka GJ Belevine dala je širok raspon podataka, od najmanjih 0,32 do najvećih 3,25, što postavlja upitnim primjenu pretvorbenih faktora na najnižoj operativnoj razini. Nakon predložene rekonstrucije poljskoga puta u šumsku cestu smanjena je srednja geometrijska udaljenost privlačenja drva odjela 18 (478 m ® 253 m), odnosno njegovih pojedinih odsjeka: 18a (373 m ® 254 m), 18b (509 m ® 214 m) te 18c (677 m ® 344 m)