Časopis Mehanizacija šumarstva počeo je izlaziti 1976. godine. Uglavnom je izlazio četiri puta na godinu. Od 2005. godine pravni su sljednici časopisa Mehanizacija šumarstva časopis Croatian Journal of Forest Engineering (CROJFE) i časopis Nova mehanizacija šumarstva (NMŠ). CROJFE izlazi dva puta na godinu (30. lipnja i 31. prosinca) na engleskom jeziku uz naslove i podnaslove, opise slika i tablica te širi sažetak rada na hrvatskom jeziku. NMŠ izlazi jednom u godini (31. prosinca) na hrvatskom jeziku uz naslove i podnaslove, opise slika i tablica te kraći sažetak rada na engleskom jeziku.
U časopisu NMŠ želimo objavljivati stručne članke, pregledne članke, prethodna priopćenja, ali i znanstvene radove iz područja šumarskoga inženjerstva koji će kontinuirano pridonositi uspješnijoj razmjeni informacija, predstavljanju ideja i vizija…

In the mid 1980s, a clear need arose in the Croatian forestry for the development of a domestic mid-sized forest tractor weighing up to 4 t, which had to meet at least two requirements: (a) have characteristics suitable for skidding timber produced during thinning operations and sanitary fellings (dead trees, tree breakage under snow, wind, ice, etc.) as well as fuel wood and industrial wood and (b) take part in ground skidding of timber with winch or with one end suspended on choker line, somewhere between medium and heavy skidders, as the share of the harvesting volume of thinnings used to reach half the total annual harvesting volume. In the late 1980s, the first generation of domestic skidders, weighing up to 4 t, appeared. After about 50 ECOTRAC V-1033F skidders had been produced, the production was halted due to new circumstances in the Croatian economy in the early 1990s. However, attempts were made to find a new, second generation skidder with improved ergonomic characteristics. Many circumstances contributed to the acceleration of the third generation tractors. This paper describes the prototypes of the second and third generation of these medium forest skidders.

Keywords: medium skidder, biodiesel fuel, one lubricant for all tractor components, ergonomic characteristics

This paper shows the results of research of exploitation characteristics of single-drum radio-controlled farmi-winch Tajfun EGV 60A in preparatory and final cut, as well as prototype of radio-controlled farmi-winch Tajfun 2×50 kN in thinning operations. The winches were installed on an adapted farm tractor Steyr 8090a. The stand age was 60, 90 and 110. Beech technical wood and industrial longwood, processed in accordance with cut-to-length method, were mainly skidded. Slopes ranged between 33 % and 70 % in thinning operations, between 10 % and 70 % in preparatory cut and they were up to 30 % in final cut. Time study was carried out by snap-back chronometry method, as well as a detailed analysis of tractor and winch effective time consumption. Interest was focused on the analysis of the work offarmi winches, whose testing was made for the first time in the Croatian forestry. Effective time of tractors and winches was established in timber skidding and winching on a skid trail, in the stand and at a roadside landing. The speeds required for pulling the chocker and load winching were investigated. The consumption of winch effective time per piece of roundwood averages 2.48 min/pcs in thinnings, 2.82 min/pcs in final cut and 3.20 min/pcs in preparatory cut. The effective time consumption of winch per volume unit is 13.08 min/m³ in thinnings, 11.27 min/m³ in preparatory cut and 8.47 min/m³ in final cut.

Keywords: farmi-winch, farm tractor, effective time, thinnings, regeneration fellings, broadleaves, slope

This paper presents the research of possibilities of use of wheel numeric, as a satisfying parameter that describes the environmental acceptability of interaction between vehicle wheels and soil in off-road timber extraction.The wheel numeric is a non-dimensional parameter (factor), which describes the interaction between the loaded wheel and soil, and its intent is to calculate arithmetically the number by which the capability of a vehicle’s mobility is assessed regardless of the consequences, based on vehicle geometric values, mass distribution, dimensions and pneumatic stiffness. This parameter can be easily measured/calculated by simple on-site measurement of soil cone index and by use of semi-empiric expressions for contact pressure.The analysis of the ratio between wheel numeric and rut depth, which can be easily measured and represents the most conspicuous consequence of the vehicle’s adverse effects on soil, showed that the wheel numeric is a suffi¬ciently good parameter for its assessment and therefore also for the assessment of the environmental acceptability. In order to get a better understanding of this problem, the basic components of the wheel numeric as well as models of diferent authors for their calculation are exemplified by a 17-ton forwarder Timberjack 1710B. The deficiency of the use of semi-empiric expressions for the calculation of wheel/soil contact pressure, as well as insufficient level of understanding of the dynamic distribution of vertical loads of a forest vehicle in different terrain conditions, especially in timber skidding, require further research in this direction.

Keywords: vehicles for timber extraction, wheel numeric, environmental acceptability

This paper gives a survey of cable systems used for primary transportation of roundwood, which are divided as follows: forest winches, highlead, and forest skylines. Special attention is focused on forest skylines through the description of their technical components, components of tehnical functions, classification with respect to different criteria, survey of models of forest skylines most frequently used today and their development trends. The field of application of forest skylines is shown in the light of the latest functional terrain classification, referred to in reference literature, for carrying out forest works in an efficient and environmentally sound way, elaborated within ECOWOOD project.

Comparison of efficiency between timber yarding carried out by forest skylines and timber skidding in the area of hilly-mountainous forests and forwarding in the area of lowland forests of Croatia, showed poor cost effectiveness of forest skylines in relation to ground based systems of timber extraction, but also their environmental friendliness, which should be evaluated in future.

Keywords: timber yarding, forest skylines, functional terrain classification

Planning of forest roads should be the first and most important phase of a complex procedure for establishing an optimum density of forest roads network. Modern techniques, technology and methods of work, primarily personal computers, appropriate software packages, GIS, GPS, etc. provide the possibility to make various simulations, analyses, comparisons and finally the selection of the most favourable solutions. What is the current situation in Croatia, are there certain problems in forest opening, how to act in future, what direction to follow – these are only some of the topics discussed in this paper. The basic conclusions can be summarised in the recommendation that the approach to planning of forest roads should be highly serious and systematic with the application of all available techniques, technologies and methods of work that could be of help in reaching fair, timely and reasonable decisions. Such an approach would result in a variety of direct and indirect benefits, and to do so strict legal frameworks, laws and regulations, should be defined.

Keywords: planning of forest roads, primary forest roads, secondary forest roads, study of forest opening, Forestry Chamber

Timber transport performed by forest truck units is an auxiliary activity within the basic activities of forest exploitation. This activity implies high production costs and is increasingly subject to market competition, and as such, efforts are being made to increase its efficiency and to enable this activity to respond to market challenges.

The load of forest truck units most commonly used to transport timber in Croatia is restricted and determined primarily and exclusively by legal provisions prescribed by the Regulations on Technical Characteristics of Vehicles in Road Transport (OG 92/05). The possibility of increasing overall efficiency and reducing costs of timber transport primarily lies in increasing the load capacity and reducing the weight of forest truck units through various measures. In addition to increasing the usable truck load, increasing transport speed with a higher number of cycles and shorter transport time can also result in the transport of greater quantities of timber. Finally, in addition to transport speed, the rate of loading and unloading is also imperative, and is greatly associated to the work capacity and quality of the crane.

When restructuring the company Hrvatske šume (Croatian Forests), care must be taken that a strategic part of timber transport by forest truck units be left within its system due to specific working conditions and biological-technical characteristics of timber being transported (high quality timber, biological deadlines, decay). In creating the future organization in the restructuring of the company Croatian Forests (Hrvatske šume), care must be taken that a strategic part of timber transport with forest truck units remain under its system due to the specific working conditions and biological-technical characteristics of the timber being transported (high quality timber, biological deadlines, decay).

Keywords: truck transport units, Hrvatske šume d.o.o., legal framework, load efficiency, increasing productivity, decreasing costs