Poštovane čitateljice i čitatelji!

Osobita nam je čast i zadovoljstvo obavijestiti vas da će se 45. međunarodno znanstveno savjetovanje FORMEC 2012 održati u Dubrovniku/Cavtatu u hotelu Croatia od 8. do 12. listopada 2012. godine pod naslovom »Concern, Knowledge and Accountability in Today’s Environment / Šumarske tehnike i tehnologije: briga, znanje i odgovornost u današnjem okruženju«. »FORestry MEChanization« (djeluje pod akronimom FORMEC od 1994. godine) međunarodna je znanstvena mreža koja proučava i promiče primjenu mehanizacije pri šumskim radovima…

This paper presents the investigation of wheel index as the parameter describing the environmental acceptability of interaction between the vehicle wheel and soil during timber forwarding (extraction) in the stand. In the Croatian lowland forests, characterized by excessive soil moisture, as stated by Anić (2001) and Poršinsky (2005), special forest vehicles, forwarders, are used for timber extraction, mainly intended for timber extraction in seeding fellings i.e. during winter (from Oct. 1 to March 30). Due to significant total mass of loaded forwarders (a medium large forwarder up to 30 tons) and frequently unfavorable soil strength in winter period, forest soil damage can occur in the form of soil deformation – formation of wheel ruts and soil compaction.
In an empirical method developed for investigating the complex wheel-soil system, or vehicle-soil system, in literature known as WES method (Waterways Experimentation Station, US Army Engineering Corps), the wheel index is used for correlating the characteristics of the vehicle and soil deformation with the soil strength. In practice, a standardized value is used for measuring the resistance of cone penetration (ASAE EP524 1999) at the depth of 15 cm called cone index (CI). Due to non-homogeneity of soil structure, Ronai (1983), Horvat (1993, 1994), Poršinsky (2005), Pandur et al. (2010), Horvat et al. (2011) noticed high data dispersion among repeated measurements of penetration characteristics.
The suitability of empirical method is also confirmed by terrain classification for performing forest operations developed by EcoWood Project (Owende et al. 2002, Ward and Owende 2003) shown in Table 1.
The objectives of this paper are to establish the actual distribution of forwarder weight (mass) by wheels (axles), determine the wheel pressure using semi-empirical expressions for the calculation of wheel pressure, determine the change of soil penetration characteristics caused by the increase of load by measuring the cone index (CI), and on the basis of the calculated wheel index estimate the environmental viability of forwarders in case of the actual timber forwarding after seeding felling.
For collecting data on soil condition, digital penetrometer Eijkelkamp Penetrologger (Fig. 2) was used with the cone base cross-section area of 2 cm2 and point angle of 30°, in accordance with ASAE S313.3 (1999) standard.
For determining the actual wheel load of the Valmet 840.2 forwarder, in this research a portable scale system WLS 101/R2K was used (BARK system-und Wiegetechnik Gmbh & CO.KG), whose calibration and development were described by Bosner et al. (2008). When measuring the axle loads, the scales were inserted into the metal platform, on which the forwarder was driven, so as to protect them from damage and in order to position the forwarder as precisely as possible on the scales to minimize the measurement error as shown in Fig. 3.
In Subcompartment 143c, the cone index was measured at 6 measurement sites (Fig. 1). At each site, 5 measurements were carried out by penetrometer. The measurement was performed vertically on wheel rut, and the measurement scheme at one measurement site with the display of the result for the measurement site 1 (door 1) is presented in Fig. 5.
The results of these measurements are the penetration curves – 5 for each measurement site, and Fig. 6 shows the results for the measurement site 1. In accordance with the standard, the values of the cone index at the depth of 15 cm were read from the diagram presented in Fig. 6. For the stand in the investigated Subcompartment, the cone index was 973 kPa – the median of all measurements. According to EcoWood terrain classification, the stand soil can be classified as (very) strong. This means that maximum value of nominal pressure exceeding 80 kPa is allowed. After felling and processing, 6 rounds were forwarded from the Subcompartment. The total load volume measured by the standard forestry method was 74.52 m3 of roundwood. By weighing the forwarder with the above described method, the total mass of the transported wood was measured and it was 68 020 kg. The average mass of the loaded forwarder was 27 340 kg.
Table 3 shows the results obtained by the calculation based on expression 1. Fig. 7 presents the values of cone index (CI) for all investigated measurement sites, while Fig. 8 presents the average values of cone index (CI) for a stand, the soil between wheel ruts and wheel ruts at all measurement sites.
The number of forwarder passes gets lower from measurement site 1 to measurement site 6. The forwarder passed 6 times through the measurement site 1 transporting a total of 68,020 kg of wood. Fig. 7 and 8 clearly show that, regardless of the number of forwarder passes, no significant volume deformation offorest soil occurred, i.e. no soil compaction was observed. This fact is contrary to the expectations, because the cone index of wheel rut and stand should be considerably different and the difference should increase with the number of forwarder passes.
The obtained high value of the wheel index (Nk > 6.25) and hence also the assessment of good forwarder mobility has been confirmed by the fact that no considerable soil compaction was observed after 6 passes of the loaded forwarder of an average mass of 27,340 kg and the same number of passes of the unloaded forwarder of an average mass of 16,003 kg. The small depth of the wheel rut is in accordance with the above conclusion.
It has again been established that the measured penetration curves and values of the cone index show considerable dispersion. Non-homogeneity of the forest soil (multi-layers, root network, etc.) considerably impede the assessment of soil strength (bearing capacity) by cone penetrometer. Therefore, it is not recommended to use the penetrometer with a small number of repeated measurements i.e. to accept the fact that the penetration characteristics should be measured »as many times as possible«, whatever it means. For this reason, it is necessary to seek more suitable methods for measuring the bearing strength and compaction of forest soil.
Even though this was not the subject of research, it has been noticed that in forwarding industrial roundwood and long length timber, the forwarder was loaded below its nominal carrying capacity due to inadequate utilization of the load space caused by different dimensions (especially length) and curvature of the wood transported.

Keywords: wood extraction, forwarder, environmental suitability, wheel numeric

Due to stand and extraction factors in selective forests of Croatia, the primary transport of wood is mostly carried out by skidders. Most of the skidders used in Croatian forestry are equipped with a double-drum winch. Out of 45 Timberjack 240C skidders, 30 are equipped with a double-drum, and 15 with a single-drum winch. The volume ranging between 0.25 mil. m³ and 0.30 mil. m³ of round-wood is annually skidded with these machines, mainly in hilly and mountainous regions of our country. This study was set up to determine the difference in productivity of single-drum winch skidders (SDS) and double-drum winch skidders (DDS). By applying work and time study, the work process of timber skidding by half-length method in selective cut was recorded. The differences between the speeds, final time consumption and load volume were analyzed by a t-test. Daily outputs were calculated based on an eight-hour work day. It was found that the achieved daily output of the skidder equipped with a single-drum winch, at distances from 100 m to 800 m, was lower from 11% to 9% than the daily output of the skidder equipped with a double-drum winch.

Keywords: timber skidding, productivity, Timberjack 240C

Technologies and work methods in forestry during the 20^th century developed either gradually or suddenly, caused mostly by the use of new machines and devices. Sudden development of means of work also influenced the Croatian forestry, where the contemporary way of forest management imposes the need to mechanize forest works with the tendency to increase productivity, decrease costs and humanize the work. One of those sudden changes happened fifty years ago – it was caused by the implementation of the motor-manual felling and processing with chainsaws.

This paper is a contribution to the knowledge of chainsaw history, from its early beginnings to 1960, when the first phase of Croatian timber harvesting had been mechanized in only couple of years.

Keywords: chainsaw, development history

Design of forest roads is a very important phase in the management of forests and forest resources. Designing a forest road consists of two subphases. The first, field subphase, involves the collection of field data that are necessary for making the Forest Roads project. The second, office subphase, consists of input data obtained by field survey in the computer program and of data processing for the main Forest Roads project with all the relative documentation (Lepoglavec et al. 2010). Using computer programs has greatly reduced the time required to design and print forest road projects. There are various programs for the design of public roads that can be used for the design of forest roads but »RoadEng« is one of the few programs that has been developed primarily for the design of forest roads. »RoadEng« is a design software package developed by the Canadian company »Softree«, and it can be used as a supplement to other design programs or as a standalone tool. It is user fiendly and also very interactive. Anyone can use »RoadEng« without being a CAD expert designer, because »RoadEng« is focused on engineering, and not on CAD.

It consists of three modules:

• Survey/Map – used to input all the data collected in the field for a range of future forest roads or just information about zero line. This Module has 8 main menus with their submenus, each having a different function related to the definition of input and data format.
• Terrain – a tool for defining the field of recorded data, mapping, design and analysis of cable lines. It provides options for the processing of various forms of topographical and other maps. This module consists of 8 main menus with their submenus.
• Location – the most complex module of this software package, used for completing the design of forest roads and the final result of this module is the complete design of forest roads with all the project documentation. The data to be processed in this module are downloaded from other modules of this software package or some other sources.

This software package was intentionally developed in the form of three separate modules because each module can work separately and can be used by different users, depending on their needs. The program is interactive, which means that any change in one detail is reflected in all road sections and on the diagram of earth masses.

Keywords: software package »RoadEng«, modules, design, forest roads

The paper presents the concept of eco-efficiency in business management and analyzes the possibilities of applying eco-efficiency indicators in forestry. It explains the correlation between environmental and financial performance of enterprises and provides classification and review of the main eco-efficiency indicators: energy intensity indicator, water intensity indicator, waste intensity indicator, indicator of global warming and ozone depletion. The overview of foreign models and experiences included the Canadian and Swiss examples with the recommendations and guidelines for monitoring environmental performance in business operations, and methodologies developed in these countries used for identifying, measuring and monitoring environmental indicators. The paper also included the SWOT analysis of the application of eco-efficiency indicators in forestry. The aim of this paper is to show the significance and contribution of eco-efficiency indicators in assessing the performance of enterprises, to process the methodology of developing and standardizing eco-efficiency indicators, and to examine the possibilities of their application in forestry.

Keywords: company eco-efficiency, eco-efficiency indicators, forestry, forest enterprises

This paper presents the current situation and condition of forests in the Polish forestry. The overview of forest management includes a review offorest resources and their characteristics, ownership structure of forests andforest lands, age structure of stands and species composition. Description is given of the production function of the Polish forests, timber felling, and organization of state forestry, as well as other aspects of forest management in Poland. This paper also provides a comparison of some indicators with the forestry in Croatia and other European countries.

Keywords: forestry, forest management, condition of forests, growing stock, annual cut, Poland

U Krakówu i Krynici od 26. do 29. lipnja 2011. godine održano je međunarodno znanstveno savjetovanje pod naslovom »Technology and Ergonomics in the Service of Modern Forestry« u organizaciji Odjela za šumarstvo i pridobivanje drva Šumarskoga fakulteta Poljoprivrednoga sveučilišta Hugo Kollataj u Krakówu i u suorganizaciji Regonalne uprave državnih šuma u Radomu. Savjetovanje je održano pod pokroviteljstvom IUFRO-a, razreda 3, radne grupe 3.03.00. Ergonomija u šumarstvu (Forest Ergonomics) i rektora Poljoprivrednoga sveučilišta u Krakówu…

Na Fakultetu šumarstva i okolišnih znanosti (University of Freiburg, Faculty of Forest and Environmental Sciences) Sveučilišta u Freiburgu održano je od 26. rujna do 1. listopada 2011. godine međunarodno znanstveno savjetovanje o razvoju kompetencija u šumarstvu. Savjetovanje je obuhvatilo različite teme: struktura i razvoj profesija i zanimanja u šumarskom sektoru, njihov utjecaj na zapošljavanje i ruralni razvoj različitih zemalja, uloga izvoditelja radova u šumarstvu te šumarski poduzetnici kao partneri u šumskom radu, razvoj kompetencija – formalno stjecanje znanja i neformalno učenje u šumarstvu, program općega i praktičnoga osposobljavanja šumarskoga radnoga kadra te povezani projekti i akcije (CONCERT, ECC, CeFCO i sl)…

FORMEC (eng. FORestry MEChanization, http:// formec.boku.ac.at) međunarodna je mreža znanstvenika i istraživača koji promiču i proučavaju primjenu mehanizacije u šumskim radovima. Prvo je savjetovanje održano daleke 1966. godine u Zvolenu (tadašnja Čehoslovačka). Polazna ideja organizatora ovakvih znanstvenih skupova bila je pružanje prilike znanstvenicima iz istočne i srednje Europe za prikupljanje znanja, poticanje rasprave o položaju šumarskoga inženjerstva, produbljivanje spoznaja iz te znanstvene discipline, te svladavanje prepreka koje se pojavljuju zbog različitih razina mehaniziranosti tehnologija pridobivanja drva u raznim zemljama. Znanstvena savjetovanja FORMEC u posljednje vrijeme održavaju se i u zemljama srednje i zapadne Europe (Italija, Njemačka, Češka) radi očuvanja i poboljšanja suradnje te razmjene iskustava među istraživačima…